BBC contrarian top 10

There is an interesting, if predictable, piece up on the BBC website devoted to investigating whether there is any ‘consensus’ among the various contrarians on why climate change isn’t happening (or if it is, it isn’t caused by human activity or if it is why it won’t be important, or if it is important, why nothing can be done etc.). Bottom line? The only thing they appear to agree about is that nothing should be done, but they have a multitude of conflicting reasons why. Hmm…

The journalist, Richard Black, put together a top 10 list of sceptic arguments he gathered from emailing the 61 signers of a Canadian letter. While these aren’t any different in substance to the ones routinely debunked here (and here and here), this list comes with the imprimatur of Fred Singer – the godfather to the sceptic movement, and recent convert from the view that it’s been cooling since 1940 to the idea that global warming is now unstoppable. Thus these are the arguments (supposedly) that are the best that the contrarians have to put forward.

Alongside each of these talking points, is a counter-point from the mainstream (full disclosure, I helped Richard edit some of those). In truth though, I was a little disappointed at how lame their ‘top 10′ arguments were. In order, they are: false, a cherry pick, a red herring, false, false, false, a red herring, a red herring, false and a strawman. They even used the ‘grapes grew in medieval England’ meme that you’d think they’d have abandoned already given that more grapes are grown in England now than ever before (see here). Another commonplace untruth is the claim that water vapour is ’98% of the greenhouse effect’ – it’s just not.

So why do the contrarians still use arguments that are blatantly false? I think the most obvious reason is that they are simply not interested (as a whole) in providing a coherent counter story. If science has one overriding principle, it is that you should adjust your thinking in the light of new information and discoveries – the contrarians continued use of old, tired and discredited arguments demonstrates their divorce from the scientific process more clearly than any densely argued rebuttal.

397 comments on this post.
  1. CC:

    I would like to comment on your claim that the argument about the reliability of climate models is false. In fact your statement is just as much an opinion as the statement of the sceptics. Predicting a warmer climate is very easy for a model, as CO2 just alters the radiative balance of the planet, but as an expert in boundary layer meteorology and land-atmosphere interactions, I have to admit that I am totally not convinced about the details that are given in the IPCC report.

    For instance, the knowledge about processes in stable conditions (at night, polar regions) is very poor, and many papers show the failure of the common surface parameterizations in these conditions. Also the success of parametrizations of convection and microphysics on a global model scale is still limited. These limitations have a large effect on the forecasts of precipitation and therefore on soil moisture.

    I agree on the prediction of the warming trend, but as it comes to the water cycle, I agree with the skeptics. The statement is thus not false, but I would classify it as disputable.

    I am slightly disappointed that the tone of the articles on realclimate is getting more and more arrogant, something that is not appropriate for good scientists as (most of) you are.

    [Response: There is a world of difference between acknowledging that models are imperfect (which they are) and claiming that they are fundamentally unreliable without mentioning what is being talked about. Do models reliably match the cooling during subsequent to the Pinatubo eruption? Yes. Do they reliably predict a northward shift in tropical rain bands during the mid-Holocene? Yes. Do they predict last glacial climates as cold as observed based on their included physics? Yes. etc. etc. Do they reliably project rainfall changes in the New York in 20 years time - probably not. Thus statements that are absent of nuance as in the 'sceptic' point put forward by Singer are indeed false, and not just a matter of opinion. What is being implicitly asserted is that modelling is a dangerous waste of time, rather than the fundamental way in which our theories of climate and climate change can be quantified and evaluated. Apologies for the anti tone of late - we will have more of substance soon. - gavin]

  2. Caspar Henderson:

    “So why do the contrarians still use arguments that are blatantly false?” Because politics, not science, is what’s at issue here. George Soros recently analysed some of the methods: One influential technique – which Republican pollster Frank Luntz says that he learned from 1984 – simply reverses meanings and turns reality on its head. Thus, Fox News calls itself “fair and balanced,” and Karl Rove and his acolytes turn their opponents’ strongest traits into their achilles’ heels, using insinuations and lies to portray opponents’ achievements as phoney.

  3. gharman:

    As a journalist that frequently writes about Global Warming issues in Texas, I have never fallen into the trap of providing “equal time” in a scientific debate when one position is obviously manufactured and/or manipulated. If there are published alternative viewpoints about aspects of current science, that is another matter. However, the out-and-out deniers that really make no effort to understand basic climate science to begin with — only their high-volume misinformed positions — simply don’t find room in my stories.
    I recently broke a personal practice of mine to engage in an online conversation with a homegrown denier in San Antonio. Most reporters I know learned their lesson a long time ago about this, that is is a hopeless endeavor. (Click on “What Lies Ahead” at http://sacurrent.com/chismelibre/forum.asp?FORUM_ID=45 to read the discussion in full.)
    I was struck by the fact that even on the fundamentals there was zero elasticity in this fellow’s debate. No movement.
    I’ve come to the conclusion that two elements seem to keep deniers in their fringe camps: a general lack of understanding of the scientific method and peer-review process (that’s across the U.S. population, I’m afraid), and the power of attachment, ie. the cultural/social identity, which seems to keep people from straying too far from familiar territory.
    That is: it takes more than access to good science to win over a denier. It takes a more fundamental shift on their part first.

  4. Erik Hammerstad:

    And today the BBC brings a story by John Christy talking about the problems of mortals and the inadequacy of modelling and the IPCC process at http://news.bbc.co.uk/1/hi/sci/tech/7081331.stm But the BBC balances by bringing a contrarian view by Martin Parry at http://news.bbc.co.uk/1/hi/sci/tech/7082088.stm

  5. Beast Of Bodmin:

    @Erik Hammerstad: I also notived http://news.bbc.co.uk/1/hi/sci/tech/7081331.stm, via a post at a Swiss-based forum I frequent: http://www.englishforum.ch/international-affairs-politics/4867-global-warming-whats-behind-9.html#post131897

  6. bjc:

    Given the level of precision that is used in model-based predictions of temperatures, precipitation and sea level, aren’t the limitations in the models problematic. That is not the same thing as saying not to use models: it simply says that the full range of uncertainties needs to be acknowledged.

  7. Stephen Berg:

    Excellent work, Gavin! Keep it up!

  8. Jim Galasyn:

    Christy says

    …our own research indicates that alarming changes in the key observations are not occurring.

    What does he think about the recent acceleration in the Greenland ice sheet and polar ice melts?

  9. Timo:

    The reason why I am a “sceptic” is because my gut feeling says that humans aren’t able to change course of Nature. The Earth has its own systems to cope with anamolies and will correct them at the appropriate time and place. And people will adapt to these “hick ups” of Mother Nature. History has proven that over and over again.

    Humans do influence the Earth (including its climate), no question about that. However, the question is; how much, in what sense, good or bad and does is it really harmful? Mother Nature is indifferent and will take its own course, irrespectively what humans will do trying to change that. Mother Nature is too big to fight against. Therefore, people will have to adapt to climate change, whatever direction it will take. It is like Judo; it is the principle of using one’s opponent’s strength against him and adapting well to changing circumstances

    The other reason for being a “realist” is the passionate way climate change (i.e. AGW) proponents claim to be right and the so-called deniers to be wrong. If a topic is becoming to passionate, mistakes can be made quite easily. And this applies for both sides.

    The most disturbing thing is the secretiveness regarding data, methods, codes and other information. If scientists are reluctant or completely unwilling to share this information which others, I am becoming suspious. If I (or others) am not allowed to analyse data and methods, how should I be convinced that you are right and I am wrong. Especially, given the fact that I have learned that climate is a natural phenomenon.

    For the time being I will remain to be a “climate realist”, adapt to a “warmer” world and further rely on Mother Nature and common sense. By the way: I am living in the Netherlands, close to the coast and a couple of meters below sea level. And I am not really concerned about disastrous sea level rise

    Thank you.

  10. Helen:

    At the end of John Christy’s article (http://news.bbc.co.uk/1/hi/sci/tech/7081331.stm) he states,
    ‘Atmospheric carbon dioxide continues to increase due to the undisputed benefits that carbon-based energy brings to humanity. This increase will have some climate impact through CO2′s radiation properties.
    However, fundamental knowledge is meagre here, and our own research indicates that alarming changes in the key observations are not occurring.’

    What ‘alarming changes in the key observations’ could he be referring to?

    We are seeing a global temperature rise at what we think is an unprecedented rate, rapid melting of glaciers and ice sheets, it seems we don’t know enough about variability in ocean circulation to say either way.. So what are these ‘key observations’ he’s talking about?

  11. Keith:

    OK. I’ve held this in for long enough. Let me start by saying that I’m a
    organic chemist working in the drug industry and work at the interface
    between biology and chemistry. So I have perhaps an interesting view on all this.

    Let’s start with the consensus thing since that’s easy to dismiss. Having a consensus view is not a scientific
    proof. A consensus opinion in science is a herd mentality. It’s poor science. This seems to be the mentality prevelant
    in the world of climate change. Now of course you could all be correct
    on AGW but consensus doesn’t make it so. Even data driven consensus. Do
    I have any evidence of this? Why yes as it happens.

    Not so long ago the scientific consensus was that peptidic ulcers were
    caused by excessive acid production in the stomach. This was backed by
    acres of scientifc work done in academia and industry. Indeed, Glaxo
    made huge amounts of money with a treatment that worked. All was well.
    The consensus seemed a pretty safe bet. Of course then these two crazy
    Aussies published a paper suggesting it was cause by a bacteria, H.
    Pylori. Oh how the scientific community laughed. That wasn’t the consensus. But then, 10 years
    later it was finally proved that they were indeed correct and then
    another 11 years before they were rewarded with their well deserved
    Nobel Prize for medicine. Scientific consensus. And we all know, as
    scientists, that this type of thing is pretty common, just not so well
    publicised. Sorry, but as a rule of thumb I’d say the scientific consensus is more
    often wrong than right. So I think we should very much put to bed the
    idea that scientific consensus has any scientific merit.

    My final point comes back to the old fav of models. The drug industry
    has spent a considerable amount of money, time and effort trying to
    design drug molecules in computers as well as modelling a massive amount of multifactorial data. And whilst some PR departments might
    show pretty pictures of the latest cancer cure being designed in a
    computer the reality is somewhat different. Even the very simplest
    molecular design experiments involving ligand and enzyme fail the vast
    majority of the time. Utterly. Even if we have a working example,
    efforts to apply it to a new system fail for unaccountable reasons. At
    molecular level we are, frankly, nowhere. This state of affairs though is better than where we
    were 20 years ago but still quite a long way from the dream. These models too always do very well when the are asked to explain historical data. We too also split out large datasets, use half to train the model and test it on the other set to check that it works. Man, a massive number of the learning (genetic algorithms etc) algorithism that you are using were first used in the drug industry. Guys, we’ve spent a fortune and we’ll continue to since it’s always cheaper and quicker than the real experiment. But that’s the rub. You have to do the experiment. The physical one. Recreate the whole system for real. Models are sold by modellers as the answer to a problem when in general they function as a means of generating new hypotheses to test in a real experiment. They serve very little real use going forward other than the reduce the actual number of experiments I will go out and do. And that, it seems, is the problem we have here. The only real experiment is one going forward which you clearly can’t do very easily. So I sympathise with the problem here. But that’s the key. The physical experiment. And, I really strongly feel that as somebody who uses models all time you have to be really for nature to really throw a curve ball at you. Frequently. This story isn’t done yet by a long way.

    I came to this site a quite skeptical on AGW. I still have some doubts
    about the quality of the data and I think the use of modelling should be
    taken with several large grains of salt. However, you have done much to
    correct many of the untruths which I’d previously thought correct. And I
    do believe that the environment is worth something and shouldn’t be
    abused. I simply do not share the consensus view that we can model what
    is going to happen in 50 years time with any level of certainty. Nature isn’t that easy.

  12. Glen Raphael:

    The counter on #6 (“It’s the sun”) includes a claim that puzzles me. The text says:

    As there has been no positive trend in any solar index since the 1960s (and possibly a small negative trend), solar forcing cannot be responsible for the recent temperature trends.

    I don’t see how the conclusion follows from the premise. Let us suppose that (according to some measurement) solar activity was on an increasing trend until the 1960s and then leveled off at a threshhold level that was unusually high by historical standards. Couldn’t that put the temperature situation out of balance such that the planetary temperature keeps increasing subsequently?

    One could imagine that there’s some range of solar output our system can adapt to with cloud feedbacks, increased storms and such but when we get outside that range the planet can’t adapt in quite the same way and as long as solar output remains at its new level the planet keeps getting warmer (or cooler) until some new feedback mechanism kicks in and we reach some new equilibrium state. In that case, the solar increase until 1960 could still be causing an increase today.

    Why is this not a possibility?

    [Response: Because you would expect a rapid warming at the beginning of the period and gradually slower cooling as you get closer to equilibrium - the exact opposite to the behaviour seen. Plus there are other signatures of solar forcing that are not seen - the stratosphere should be warming, not cooling if the solar idea was correct. The cooling however is exactly what is predicted by GHGs. - gavin]

  13. Frank:

    I have to agree completely with the first comment and disagree with the reply given by the author of the post. Models are not reliable, that means, when they are used to forecast global warming the forecast is subject to inadequate parameterization of physical processes, therefore the results of the model can only be trusted to the extent that we understand these inadequacies.

    One can argue whether asking for reliability is unnecessary from a political point of view (and maybe impossible to attain in a model), but that is certainly not the same thing as asking for everybody to agree that models are reliable (when they are simply not). Science people tend to think that no credit should be given to the right answer for the wrong reasons. We know models are deficient to the extent that our knowledge of key physical processes is deficient. Why then force people to think that global warming is going to occur based on model “evidence”? Is not the main reason for using models that we want to learn how the climate system works?

    The author mentions that models are able to match the cooling due to the Pinatubo eruption (among other successes). I am interested in the nuances of this affirmation. Do we know reasonably well what was the aerosol composition after the eruption? Do we know good parameterizations of the aerosol radiative effects? Or is the model match of the cooling more an exercise in fitting the aerosol properties so that we obtain the observed cooling. Do models reproduce reliably the vertical temperature change and spatial distribution after the Pinatubo eruption or only the mean surface cooling?

    [Response: You fall into the same false dichotomy as Singer. The idea that there are simply two classes of model "reliable" or "unreliable" is just not correct. It depends entirely on what it is you want to know about. The climate models are pretty reliable at global mean changes, variations as a function of latitude and for large scale phenomena - they are not reliable for short term, local projections. If you want to have a heuristic test for what you should rely on and what you shouldn't, ask two questions - do the different (somewhat independent) models give the same response? and are there good observational and theoretical understandings for this response? If the answer is yes, then that's a pretty good guess. If not, then the question is not yet resolved. This isn't perfect and all the models could agree and still be wrong (due to some key piece of physics that everyone is missing) - there was an example of this in the Antarctic ozone hole which came as a surprise to everyone.

    You make one other mistake - we don't think that global warming is going to continue simply because models say so. That result is purely a function of our ever increasing burden of greenhouse gases - specifically CO2, our knowledge of radiative transfer (which is pretty good) and our assessment from past history for how sensitive the climate is (see here). No models required (though they do help).

    With respect to Pinatubo, I recommend a section in our recent paper which discusses just that. Pinatubo was pretty well observed and so we know what the aerosol load was, what the relevant aerosol size distribution was, what the impact on the short wave and long wave was, how much cooling there was, how much reduction in water vapour and how the wind patterns reacted (a more positive winter NAO). All of these features emerge from model simulations and the match to observations is very strong. - gavin]

  14. Michael:

    Gavin, what is your response to the idea that climate science is in its infancy? You come across as very sure of yourself. Your hesitance to look at your own work with a grain of salt is practically forcing your audience to look at you with a grain of salt. I am not referring to the AGW vs deniers scuffle, but to your positions on climate sensitivity, the MWP, and your trust in climate simulations.

    [Response: Possibly adolescence rather than infancy, but my apparent confidence in debunking obvious rubbish is not very relevant to dealing with real issues. In my own work, I am daily made aware of the shortcomings of our understanding - in proxy records, aerosol physics, turbulence to name but a few areas. And I like to think that my papers are extremely up-front about potential problems - so much so they are frequently quoted back to me as if I didn't write them. On climate sensitivity, I think a lot of evidence points to something around 3 deg C being the most likely and hoping for a small number or panicking due to to the potential for a larger number are not sensible positions. The MWP is pretty much irrelevant for understanding either forcing or responses or internal variability since the error bars on everything mean that nothing is usefully constrained. Climate simulations are simply quantitative workings out of our basic assumptions - they work pretty well (which comes as a surprise if you are involved in building them), and they get better as you improve the basic physics. I trust them as far as they match up to observations - and in the paleo climate they do surprisingly well. - gavin]

  15. Lawrence Brown:

    This is a lot of the same old same old on the part of the contrarians. Either The data isn’t good,the use of 1998 instead of the trend before and since, or computer models are imperfect (hello! what isn’t). Water vapor as a forcing rather than a feedback, and,of course, the Sun.

    These arguments have been debunked and refuted many times over. Gavin asks “So why do the contrarians still use arguments that are blatantly false?” Maybe the now famous statement by Jack Nicholson’s character in ‘A Few Good Men’ applies- “They can’t handle the truth!”

    [edit]
    Further enhanced greenhouse warming isn’t unstoppable,yet, but another 4 years of mostly voluntary measures by the World’s largest emitter of GHG’s will take us pretty close to that catastrophe waiting to happen.

  16. Dave Rado:

    Re. #12, and Gavin’s reply, I wish Richard Black’s counter had made the point about the stratosphere cooling, and also about nights warming more relative to days and winters warming more relative to summers, and so on, as I think it is the multiplicity of different strands of indisputable evidence such as this is what will convince laymen.

  17. Dave Rado:

    Re. Keith, #11, please read Spencer Weart’s histories of Simple Models of Climate, and of General Circulation Models of Climate, as they will open your eyes, if you are as open-minded as you appear to be. Of course there are lots of uncertainties, the biggest one being what human emissions will be in the future; but the uncertainty ranges are clearly stated in the IPCC reports.

  18. Alastair McDonald:

    Of course the models match Pinatubo. The scientists have had over ten years to get the parameters right. But they still have not solved the tropical lapse rate problem, nor did they get the speed of melting of the Arctic ice correct. Moreover they still cannot reproduce the rapid climate changes at the start and end of the Younger Dryas or any of the other Dansgaard-Oeschger events.

    Just as the sceptics will not admit they are wrong, the same is true of the scientists. It is pointless telling a sceptic that AGW (anthropogenic greenhouse warming) is a danger, and it is pointless telling a modeller like Gavin that his model is wrong. No one ever admits they are wrong because it means losing face. See “How to Win Friends and Influence People” by Dale Carnegie.

    What is happening is that the scientists are defending their models against the sceptics instead of looking to see why they are wrong. Meanwhile the world is racing towards another rapid climate change and catastrophe!

    [Response: Nice one alistair... How might you explain that the predictions of cooling from Pinatubo were done prior to them being recorded? (http://pubs.giss.nasa.gov/abstracts/1992/Hansen_etal.html ) - gavin]

  19. Dennis:

    Your Statement:

    So why do the contrarians still use arguments that are blatantly false? I think the most obvious reason is that they are simply not interested (as a whole) in providing a coherent counter story.

    My response:

    They are speaking to their audience. Those people don’t read science blogs. The audience believes anything that sounds like a rebuttal right or wrong, truth or fiction. I spoke to a flight crew member perhaps a pilot or co-pilot, not stupid individual. But he said “sir the planet has been changing for millions of years”. I told him ” I know, I am a geophysicist, every dramatic shift in climate has had dire circumstances for extant life!”. He gave me a blank stare, and walked away (no new data accepted period). What to do?

  20. Doug:

    Keith complains of a “herd mentality” among those who perceive anthropogenic global warming. I think I know what he’s talking about, but I don’t think it applies to the climate science community. I work in forest conservation in the northwest U.S. and I regularly confront herd mentality among those who profit from logging. They see chainsaws as the solution to every problem in the forest. These herd thinkers tend to really latch onto an idea and block contrary ideas from their thinking. Example: excess fuel in the forest must be removed by logging rather than by reintroducing fire. Whereas the climate science community actually seem to exhaustively explore possible alternative explanations for their observations. This is healthy science.

  21. Frank R:

    Gavin,

    I agree with you that models cannot be classified as reliable and unreliable without a proper context. That said, reliability of models can only be called for when one expects to take action using model results. This is the political use of the model. The scientific use of the model is attempting to shed light into the workings of nature. For this particular use, reliability is not really important, as long as one is keeping track of “the potential problems”.

    I am reading the Pinatubo section of the paper, and I have to say that I like better your moderate scientific prose when it comes to the uncertainty in the aerosol content and properties, than the tone of certainty that is implied on your blog comments ;)

  22. Dave Rado:

    Gavin wrote in response to post #13:

    You make one other mistake – we don’t think that global warming is going to continue simply because models say so.

    Part of the problem here is that I have frequently heard climate scientists on TV and radio programmes, when asked how we know for sure that current warming is “man-made”, reply: “because the models do not match the observed data unless human-emitted CO2 is taken into account.” I think taking that line is a big mistake, as you say there is plenty of evidence apart from the models, especially radiation physics; but this line is s used by a lot of climate scientists when talking to laymen.

  23. cce:

    Off topic. Maybe this has been posted before, but has anyone seen this particular piece of lunacy?

    http://www.longrangeweather.com/Long-Range-Weather-Trends.htm

  24. Alastair McDonald:

    Nice one Gavin! You are right – the Pinatubo match was a good fit.

    However it was caused by changes in solar radiation due to a dust cloud, not changes in greenhouse gases. Therefore it was not a good test of modelling greenhouse gases See “The Dust Settles on Water Vapor Feedback” Anthony D. Del Genio Science 26 April 2002:
    Vol. 296. no. 5568, pp. 665 – 666 DOI: 10.1126/science.1071400

    Yet it was claimed as a success by the anti-sceptics, and you are still claiming it as a success. There is a spinning of the science to support your models, and dismissal as irrelevant any anomalies such as the tropical lapse rate which could point to errors. I have to agree with the point made by CC in #1 “that is not appropriate for good scientists as (most of) you are.”

  25. Joe Duck:

    Gavin: The climate models are pretty reliable at global mean changes, variations as a function of latitude and for large scale phenomena – they are not reliable for short term, local projections. If you want to have a heuristic test for what you should rely on and what you shouldn’t, ask two questions – do the different (somewhat independent) models give the same response? and are there good observational and theoretical understandings for this response? If the answer is yes, then that’s a pretty good guess. If not, then the question is not yet resolved. This isn’t perfect and all the models could agree and still be wrong (due to some key piece of physics that everyone is missing)

    Gavin thanks – this statement was *extremely* helpful to my understanding of how modellers view the climate models and why the model data can have problems but still strongly suggest AGW.

  26. Richard Ordway:

    “I simply do not share the conscensus view that we can model what is going to happen in 50 years time with any level of certainty. Nature isn’t that easy.”

    You are gravely mistaken, misinformed and do not know what you are talking about. Why don’t you read here first before making broad pronouncements on something you obviously know nothing about.

    Future climate model results have ranges- not specifics because there is no consensus on specifics.

    http://www.realclimate.org/index.php/archives/2007/07/green-and-armstrongs-scientific-forecast/

    Where in the world did you ever get an idea that “with any level of certainty” the scientific community predicts what exactly is going to happen?

    If you mean a conscensus that the Earth’s average surface temperature is going to increase over the next century, then you are right.

    Literally, with the increasing forces involved, you or anyone else has to dream up a counterbalancing force of equal or greater magnitude…maybe an asteroid or Yellowstone…but even then they would have to be extremely large…the added Co2 and Methane would probably still remain doing their work after the “incident” was over.

    As they say, barring an extrordinary “biblical event”(sorry), there are simply no forces strong enough to accomplish this…and no one on Earth in their wildest imaginations can think up or even come close to proving that any large enough “reasonable” forces exist to counterbalance GW no matter how hard they have tried.

    Jeees, do you have any idea at all the magnitude of the forces involved that are powerful enough to have changed the Earth’s average surface temp by 1 degree F in 100 years???

  27. caerbannog:


    he consensus seemed a pretty safe bet. Of course then these two crazy
    Aussies published a paper suggesting it was cause by a bacteria, H.
    Pylori. Oh how the scientific community laughed. That wasn’t the consensus. But then, 10 years
    later it was finally proved that they were indeed correct and then
    another 11 years before they were rewarded with their well deserved
    Nobel Prize for medicine. Scientific consensus. And we all know, as
    scientists, that this type of thing is pretty common, just not so well
    publicised….

    And how did those Aussies ultimately prevail? Did they write op/ed puff-pieces for right-wing political rags? Did they go on conservative talk-radio shows to complain about how they were being repressed? Or did they succeed in convincing their peers by producing outstanding research that was published in peer-reviewed journals?

    To make a credible case, you are going to have to show us some outstanding research challenging AGW that the deniers have published in peer-reviewed journals. Nobel Laureates don’t earn their laurels by publishing puff-pieces in the Wall-Street Journal or the American Spectator.

  28. Mary C:

    Re 9. Timo – First I think you have to get rid of the idea of something called “Mother Nature”. There is no such being, just physical laws within which or through which our universe is bound to operate and which scientists are constantly striving to understand. Human beings are simply one aspect of that universe, also constrained by those same physical laws.

    There seems to be a belief that it is arrogant to say that something so insignificant within the greater scheme of things as man can have an impact on the operation of that universe. And that, I daresay, is indisputably true. But, nevertheless, man has the capacity to impact a tiny speck of that universe through his actions. If you doubt that something insignificant can change the earth, then you are unaware of history of the earth as it is understood by scientists today. The earth is not a static place, unchanged and unchanging since the birth of the universe 13.5 billion years ago or even since its own birth 4.5 billion years ago. All those physical laws keep it in a constant state of change. And one of the changes was brought about by bacteria:

    “It is widely believed that 2000 million years ago the cyanobacteria—oxygen eliminating photosynthetic prokaryotes that used to be called blue-green algae…effected one of the greatest changes this planet has ever known: the increase in concentration of atmospheric oxygen from far less than 1% to about 20%. Without this concentration of oxygen, people and other animals would have never evolved”
    Margulis, Lynn and Karlene V. Schwartz. Five Kingdoms, 2nd edition. W. H. Freeman and Company 1988. p28.

    Human release of additional carbon dioxide into the atmosphere is unlikely to bring about the kind of profound change that the advent of significant quantities of free oxygen into the atmosphere had. Life will not disappear, and even human life will most likley continue, until, as you indicate, still greater changes may wipe it out completely. But the changes that could be brought about because CO2 will act within the atmosphere as the physical laws say it must may very well have consequences that will be painful for humanity and that could destroy the world as we know it today. Given that fact and given the fact that we have some good ideas on how we could reduce the extra CO2 we are currently putting out, why should we not make an effort to eliminate or at least minimize a threat?

  29. Richard Ordway:

    # 11. Ok, Keith. re. “peptidic ulcers proves that scientific consensus is bogus.”

    Gavin puts his time and reputation on the line with this blog and cites multiple, exact world-wide publicly-available references as all *real* scientists do.

    So you now do the same, Keith. Give us verifiable references (internet links that we can click on) to verify what you are talking about.

    I couldn’t even find a definition of the phrase “peptidic ulcers” when I checked internet sources for “peptidic ulcers” for five minutes (maybe it exists, but I could not find the defintion.)

    At best, this is an extremely rare subject, at worst a strawman.

    So, give your clickable references and then we can talk…

  30. Svet:

    The response to “2. IF THE AVERAGE TEMPERATURE WAS RISING, IT HAS NOW STOPPED” is “cherry-picking”. What troubles me is that the HadCRUT3 Global surface temperatures graph does show a distinct leveling off over the last six years. I know that you shouldn’t just look at a few years in isolation but six years does seems a long time when you consider that the dramatic warming took place in the ten years of the nineties. My question is hypothetical. If six years is not enough to be significant then what length of time will be significant? Put another way, if the leveling off continues for another four years will it then be significant?

    (I know that the GISS graph doesn’t show this leveling off and I suppose looking at the Hadley Centre figures is a kind off cherry picking. However, you have to choose one or the other and the Hadley Centre is a respected organization isn’t it?)

  31. Majorajam:

    Good post. The embarrassing lack of internal consistency in ‘skeptic’ community arguments is the most reliable way a lay person such as myself can begin to know what to believe. For example, early on in my education, I came to one former Harvard professor’s blog and read a post that cited three studies that contradicted the theory of AGW, (or should that be in scare quotes?)- entitled something to the effect of, ‘so much for a consensus on peer reviewed literature’. All well and good except in one problem: each study patently contradicted the other, (in one it was the sun, another the oceans, and the third, well, it was all a figment of our imagination). Neither this former professor nor his minions of educated sounding (and rather rabid) commenters so much as noted the peculiarity in the thread. So it is certainly useful to the lay person to highlight this overwhelming red flag, as it gives them evidence they can relate to and does not resort to beating them over the head with arguments from authority (consensus, consensus, consensus!), necessary though these can sometimes be.

    If I may though, though I understand their demise has heretofore been greatly exaggerated, (mimicking their claims), the power of denialist arguments over the public and policy seems to be waning, (witness a full week of major network programming in the United States, American Football included). What isn’t waning are the, IMO, badly flawed economic arguments against mitigation, and, frankly, more effort needs to be expended here to justify anything resembling a policy with teeth (e.g. mandated/operative targets). The Stern Review was a notable failure in establishing the necessary economic analytical framework: any CBA that can be shown to depend largely on the relative merits of esoteric discounting parameters is dead on arrival. The most promising route for getting somewhere in that regard is an approach that better describes the real world issues, (issues that Stern highlighted but didn’t directly model), a la what Weitzman has done, (though we don’t know for sure what types of answers we would get, his approach would likely auger for more aggressive policy than a standard CBA). However, James Annan has raised questions about the modeling of the climate in this work.

    Pursuant to the objections he has raised, I have two questions for the blog moderator(s) (read your response to my question in the other thread Gavin- thanks), and/or anyone else who can give me a good answer: if you are modeling average temperatures as a scalar of emissions over the maximum timescale that could be considered relevant for current emissions policy- say two centuries- is it best to describe that scalar as an uncertain single point estimate or an uncertain distribution of scalars? I wasn’t able to determine this from what I read of the certainty of uncertainty thread.

    Secondly, is it at all possible, given the current state of the science, to come up with any estimates of the magnitude and timing of long-term feedbacks- what Annan and Hargreaves have treated as forcings in their work that places very tight limits around climate sensitivity? One that could be employed in economic modeling. The question applies both to estimates and error bars around timing of these effects kicking in, timing around how long they will take to come to full fruition if relevant, (such as with ice sheet melt), and the magnitude of their effect on climate if they did. I’m not expecting a long answer actually, just a sense of how limited is the knowledge.

  32. Ray Ladbury:

    I have never understood the seeming comfort that denialists take in trying to discredit the models, as if they were somehow discrediting the hypothesis of anthropogenic causation thereby. In reality, the case for anthropogenic causation does not depend in any way on the models. There is simply no doubt that climate change is occurring, and there is no other credibel driver that could provide the energy driving that change. Indeed the models are the only thing that limits the risks posed by climate change? How else would we know to expect 3 K per doubling and not 10 K per doubling? How else do we allocate mitigation resources effectively? Lack of certainty is not an excuse for inaction–let alone for complacency.

  33. PJB:

    Re 11: I don’t understand how people can continue to pull the “scientific consensus is not scientific proof” card. Don’t people who make this statement understand that scientific consensus is the closest thing we will ever get to proof? Taking that road might as well be an argument against the whole of science and the means by which we come to accept anything as fact. The question “is there scientific consensus?” is asked by laymen, like myself, to feel confident that conclusions like AGCC, are made with an acceptable degree of certainty. Oreskes’ paper was designed to be a reasonable response of Science to this question. The IPCC exists specifically to this purpose (assuming policy makers are people). Unless I’m mistaken, scientific consensus is not a consensus of opinion (as you seem to imply with your herd mentality comment), but one of the actual science. The results of one paper help verify those of another, climate models help verify the basic assumptions of the science. This synergy that results when results do not contradict one another reduces the uncertainty. Throw in the peer review process, and the fact that many scientific papers go out of their way to challenge the conclusions of others, and you’ve got a pretty solid system. So while there may be many questions within climatology that remain to be answered, didn’t Oreskes’ paper do a reasonable job of letting us laymen know how well we can gauge the (un)certainty of the response to our question, “does the Science agree that AGCC is real?” A slightly less objective answer would come from the question “is the Science really sufficient to support this conclusion?” What’s the IPCC for again?

  34. Kevin:

    Keith (#11):

    In your example 2 scientists published an alternative view going against the consensus. and they convinced enough people that enough evidence was built to support their view. Now there is a different consensus and the two scientists have a nobel prize.

    Are you saying that climate scientists are all so scared of going against consensus that there aren’t a few in the world willing to try for a Nobel prize by proving everyone wrong? If not, then why aren’t there scientists publishing contrarian papers for everyone to laugh at, but be unable to prove wrong?

    Additionally, a new consensus has now arisen in your example. Does this mean if someone publishes a paper against the new consensus they should be immediately given the Nobel prize, or perhaps more research be done? If that further research proves to be wrong, what does this mean for the consensus?

    You may be a scientist, but do you understand the scientific method? All theories in science are theories of consensus – the theory with the most supporting evidence is the theory of the consensus. If you want to knock it down you don’t just throw out more theories, you need facts that contradict or are unexplained by the current theory. And the new theory has to explain the old facts and the new facts.

    So far climate sceptics have been unable to find contrary facts or really even explain all of the current facts.

  35. petefontana:

    What is an “entrainment coefficient”? Can anyone explain why it matters so much to the climate and climate models?

    http://www.pnas.org/cgi/content/abstract/104/30/12259?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=Association+of+parameter%2C+software+and+hardware+variation+with+large+scale&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

    Thanks in advance.

    [Response: In the tropics, the surface heating by the sun makes the atmosphere unstable. Convection results. Because of the large amounts of water vapour, clouds will form during that process and release more heat leading to further convection. The end result is a cumulus tower that can reach the tropopause (and a lot of rain). These moist convective plumes are highly turbulent and so they 'entrain' dryer air from outside the plume as they rise. To entrain means to gather air up from the environment and mix it with the plume. The entrainment coefficient in the Hadley Centre model controls how much air from outside the plume mixes in. If it is small, the plumes are smaller and rise higher, if it is large, the plumes are fatter but do not rise as high. This effects the cloud amount, upper tropospheric water vapour, temperature values and the Hadley circulation and so the climate can be quite sensitive to it's value. In the real world, things are not this simple and different plumes will have different entrainment rates - more sophisticated parameterisations use a spectrum of plumes to do a better job of this - however, I think it's fair to say that there isn't a really good theory that predicts what the entrainment should be in any particular circumstance in the models. - gavin]

  36. Chris C:

    RE 24

    No one said Pinatubo was a demosntration of GHG forcing, but a demonstration of model adequacy. The problem is that ‘skeptics’ won’t be happy unless they can have another planet Earth which we can use for experiment and have time-travel capability. Until then, bashing models, and using worn-out arguments will keep happening.

    Chris

  37. cat black:

    I find it generally shocking that the scientific community is not allowed to have a “consensus” when confronting a set of observations. How else are we to proceed with the work except to agree that the data is 1) real and 2) reflective of nature? And if it is real and represents natural realities then why can we not all, as intelligent people, agree (pending new observations) on a rational explanation for the observations? Science is a process, not a product as such, and it loops around endlessly taking new input and creating new ideas on the fly. This is a feature, not a bug, and it allows us to make provisional assessments and MOVE ON. The only reason someone would have trouble with that is if they think of the world in terms of unchanging absolutes, as if there can only be One Truth and not, instead, a working set of theories and a cloud of old and new observations that both support theory and yet point in additional fruitful directions.

    Likewise, when I hear someone say “well how can people possibly change climate? It makes no sense to me” as if that, in itself, is both the question and the answer, and to miss the obvious relevant fact that there are 6 billion of us, and all our unsleeping machines, and our cities and factories, working unceasingly in the effort, and then my head wants to explode with their narrow and self serving, relentless stupidity.

    I understand that there are dense scientific theories involved, and a crushing quantity of data and observations, and that this is overwhelming to anyone without the time and education to wade through it. But given that, and not saying that every single living human must understand entirely the total of the work, cannot people who are not able to wrap their heads around it simple — oh say — accept the current theory, and it’s inherent implications for policy, and otherwise STFU?

    Seriously. John Coleman (The Weather Channel) claims to have (I paraphrase) read dozens of scientific papers, spoken to many scientists, and thought about the question “a lot” and he is now convinced that AGW is a scam. My god, what an ego. Free speech issues thrown aside, what gives him the privilege to trash talk the life’s work of thousands of dedicated men and women who have probably already *forgotten* more about climate theory than John Coleman will ever know in his entire life?

    It’s really just anti-science rearing its head. So long as science, medicine and technology generate more stuff to buy people are happy. But once it turns up something troubling the ad homs start, it’s strawmen at every corner, and “who really trusts all that voodoo science anyway” all over the farm. Look people, you screwed up, OK? We all screwed up. Data is in, evidence all over the place. Things are falling apart around our ears. Time to face the music. It was a nice ride while it lasted, nothing lasts forever, thems the breaks. Get over it. Think about that whole “what is a solar economy anyway” question and really apply yourself to the answer, because like it or not, kick and scream all you like, doesn’t matter, the party is over.

  38. wayne davidson:

    Bravo BBC! Great idea to find any insights behind all that contrarian bluster. I suspect that the low level of response to the reporters survey shows a certain degree of hesitation, perhaps healthy scepticism about a stance melting like Arctic Ocean ice in July.

    The question about models being flawed is not fair, because they pointed current warming in the right direction for decades, they have not changed projecting this warming trend despite a contrarian inspired certainty , inescapable variation, which requires a profound cooling trend to come any day, month or century, a perfect non argument presented to sway lethargic politicians in not changing their present pollution embracing course. Models represent all we know about the atmosphere, they forecast next few days temperatures with astounding precision, anti model chaps may have forgotten that they also project cyclone/hurricane tracks with unheard of precision compared to a few decades ago. All we know is perhaps not all there is, exploration through observation is not enough mingled with academic theory (models), there are many integrations left to do, I suggest doing more work in horizontal observations rather than always with data from vertical profiles. The two have to match, and I have found proof that vertical data extrapolations are not reconciled with horizontal observations.

  39. EricM:

    RE: 23
    Disregarding the references to volcanoes and solar irradiation, what is your objection to the graph? Why is it lunacy? Is the simple cyclical plot of temperature versus time over the last 4500 years wrong? If not, then you should print it out and tape it to the wall as a daily reminder of why there are so many “skeptics” about AGW. Many scientists get so wrapped up in the technical discussion of radiative forcings, feedback mechanisms, the reliable of modelling, etc, etc, that they lose sight of the forest for the trees. This type of chart is way too basic to “explain” what is going on and is thus disregarded. The layman, however, looks at the simple temperature versus time chart and says, “by golly, looks like we’re warmin up – nothin near the peak though. Hey Bubba, grab me another beer will ya?”
    I think Timo in 9 has it right. Most people see a cycle that’s happened before, not a crisis. Mother Nature will adapt. So will we.

  40. Edward Greisch:

    I could use some help with http://www.alternet.org/environment and other places on AlterNet. I direct the readers of http://www.alternet.org/environment to RealClimate once in a while. I try to convince them that AGW requires some really drastic changes and get resistance just like what RealClimate is always fighting. I think that there are several types of reasons for the resistance. Some of the reasons:

    The coal industry has a gross income of $100 BILLION per year. That $100 BILLION per year could be easily sunk by the nuclear industry unless people can be persuaded that nuclear power is dangerous. That $100 BILLION per year could also be decimated if people got serious about AGW. Do the coal companies have an incentive to lead people astray? Yes. Is $100 BILLION per year enough incentive? Yes. Can the coal industry afford to hire doctors, economists, environmentalists, web site designers, computer scientists, psychologists, advertising agencies, authors, publishers and lots of other people on $100 BILLION per year? Of course. Can the coal industry afford to set up hundreds of web pages on hundreds of computers in hundreds of locations and “game” the search engines on $100 BILLION per year? Yes. And they do.

    People try to use the web to find truth rather than doing it the hard way: getting an education. The search engines do not understand the web pages they find. They are just machines. They have no idea of whether or not the web pages they find tell the truth. In the US, we have “freedom of speech,” which means that nobody has to prove that anything is true before publishing it. The result is that lies get published far more than the truth. The average person is completely clueless and believes whoever seems to have the most authority. How hard is it to find the truth on the web? Very hard. Gavin, if you teach any courses, are they FREE on the web or do you charge tuition? If they were free, would they be easy and fun like cartoon shows, the level most people are willing to watch? Is your university library on the web as free downloads or do students have to pay outrageous prices for textbooks? Do you game the search engines like the coal companies do? If you look into how search engines sort out web pages, you will find out that they do mathematics on the number of links, etc. to figure out who the authority is. Search engines don’t ask human scientists for evaluations.

    Of course, the evolutionary design of the human brain is also a barrier to sanity.

  41. Edward Greisch:

    There has been another confirmation of the idea that we will cause our own extinction in about 200 years if we don’t stop AGW. Extinction of Homo Sapiens is such a dire possibility that no such chance is tolerable. Severe action must be taken even on scant evidence. Here are the URLs again on how it happens:

    http://www.geosociety.org/meetings/2003/
    prPennStateKump.htm

    http://www.astrobio.net/news/modules.php?op
    =modload&name=News&file=article&sid=672

    http://www.astrobio.net/news/modules.php?op
    =modload&name=News&file=article&sid=1535

    http://www.sciam.com/article.cfm?articleID=00037A5D-
    A938-150E-A93883414B7F0000&sc=I100322

    http://www.astrobio.net/news/article2509.html

    http://astrobio.net/news/modules.php?op=
    modload&name=News&file=article&sid=
    2429&mode=thread&order=0&thold=0

  42. jacob l:

    you might want to compare the bbc’s questionnaire to that of Steve Milloy
    bbc skeptic questionnaire
    I thought the bbc’s was much better.

  43. gator68:

    Keith,
    You story about the ulcers is a good one. However, before the evidence came out about the virus, why shouldn’t someone believe ulcers were caused by excess acid? Especially if someone made a drug based on this idea that worked? And what changed — was it bloggers complaining, or people doing experiments and publishing results?

    If the theory of AGW were untrue, all the deniers have to do is show where it is wrong. Do the science. Publish data. Instead, we see propaganda by non-experts promoting a mish-mash of conflicting arguments. This isn’t a case of “consensus” science vs. brave mavericks. This is a case of an evidence-based theory being confronted by evidence-less politics.

  44. pete best:

    Hang on, the debate is over in some parts of the world. Europe for one as plans are afoot post kyoto etc to cut emissions significantly in principle and hopefully in reality. The UK is ratifying a climate change body and written into law on emissions cuts. USA and Asian governments recognise threat and have some current possibility of acting equally across all 52 states.

    Real climate has always been pragmatic and If I understand your position right it is that with significant emissions control started by no later than 2015 (400 ppmv first realistic 2C warming probability) and resulting in no more than 450 ppmv ultimately (as this is the guaranteed 2C minimum rise by this CO2 level) we can then stop rises from going above this temperature.

    All the major players now accept mainstream warming is occuring mainly because it is only 20 years since the human signal has arisen from natural variability.

    The contrarians are losing the battle but will we be in time is the issue for me.

  45. John:

    #1 I must say I have to agree with your statement. I think a key ‘sceptics’ argument is that computer models are easy to get right in hindsight, but harder to get right looking forward. The trick, of course, is to make a model predicting the future which actually comes true. I think more people would believe the global warming theory if any of the IPCC models actually got it right. One only has to look at the 2001 IPCC forward looking forecast to see how wrong it was. Current global temperatures (2007) are below the ENTIRE RANGE predicted in that report.

    [Response: This is just not correct. 2007 is on track to be the 2nd warmest year on record and the long term trend of ~0.2 deg C/decade is exactly in line with projections. The specific projections from TAR are compared with obs in Rahmstorf et al (2007, Science) and show a very good match to trends. It should go without saying that individual years are subject to 'weather' noise variations, but I don't think you even need to invoke that here. - gavin]

  46. Douglas Wise:

    I agree with everything written by Keith in #11. I, too, started reading this website, sceptical for exactly the same reasons as Keith, and, like him, have become less so. Keith requires a real experiment to validate the models and points out the obvious difficulty of undertaking such. However, it occurs to me that there may be extant data that would allay most of my prevailing doubts. Having asked for it in a previous thread, I received no satisfactory response. If I may, I’ll try once more.

    I accept that CO2 is a greenhouse gas and that combustion of fossil fuels and deforestation have resulted in and will continue to result in atmospheric increases not seen in the previous 650000 years. In theory, this should lead to greenhouse warming which may be exacerbated by a positive water vapour feedback. The former will certainly happen but its extent may or may not have been exaggerated by the models. I lack the knowledge , experience and probably intelligence to make a useful judgement. I must therefore accept what I’m told by the model experts as an article of faith or look for corroboration from real data. The data that I think would convince me relate to changes in brightness temperatures as measured from space in various ranges of the infrared spectrum.

    I have read that the brightness temperature of infrared in the CO2-relevant band is 215K, that in the water vapour bands 275K and that passing to space unimpeded by greenhouse gases is 288K. I would expect the last figure to remain constant. With increasing CO2, I would expect the figure of 215K to be reducing. Given positive feedback from water vapour, I would also expect the figure of 275K to be falling. Are my assumptions valid? If they are, is there evidence for falling brightness temperatures? If not, why not?

    I would be extremely grateful for a response from Gavin or anybody else who is an authority on this subject.

  47. Rikard:

    Gavin responded thus:
    [Response: Because you would expect a rapid warming at the beginning of the period and gradually slower cooling as you get closer to equilibrium - the exact opposite to the behaviour seen. ... - gavin]

    As you have heard before, one of the sceptics arguments is the mismatch between warming (starting in the late 70:s) and the rapid increase of man-released CO2 (starting in 1945). Thus, they can refute your argument with the same argument you use for refuting them. Any comments?

    Also, the arguments from the “cosmic ray” theorists refers to a particular kind of solar activity, which peaked in the late 1990:s (particles of 10 GeV as derived from measurements of impacts in ion chambers, see eg Ahluwalia, 1997). While your argument refutes general solar activity as a sole climate driver, it doesn’t address this particular competing hypothesis. Can you further your argument in this respect?

    [Response: I'm not the one claiming that there is only a single driver for climate change. You need to take everything into account (including solar). When you do, the offset in the 1940s to 1970s is small. But if you take out GHGs and increase solar to anything you like, you still don't get a match with the recent observations. You just can't get an accelerating trend in the last couple of decades if your forcing stopped growing in 1960.

    The Ahluwalia curve (which is pushed very strongly and uniquely by Nir Shaviv) is made up of two separate cosmic ray curves (neither of which show a trend) but are offset. They are stitched together so that the 'trend' comes from starting at the lower curve and ending with the higher one. No continuous record shows any such increase. It is, to say the least, unconvincing. - gavin]

  48. Keith:

    Wow. It’s good to see that I have provoked a debate. Firstly let me apologize, Richard, that my typing was not as good as it should be. It is Peptic ulcer rather than peptidic ulcer. That should clarify things as far as looking at the story online as to how this story developed.

    http://digestive.niddk.nih.gov/ddiseases/pubs/hpylori/#1

    As for the two Nobel winners the story is summarised here

    http://nobelprize.org/nobel_prizes/medicine/laureates/2005/press.html

    The story goes that Barry Marshall and Robin Warren, in order to prove, to a skeptical scientific community, their theory, actually drank a suspension of H pylori so as to get an ulcer and then showed that treatment with antibiotics cleared the ulcer.

    So caerbannog and Ricahrd, there’s my clickable links. Oh and H pylori isn’t a virus. It’s a bacterium. Totally different.

    Thanks to Dave Rado for the links. Fabulous summary of some of the work and I recognised some of the methods that we use to attempt to computationally describe biological data. I wish I could respond with some decent links to similar issuse in my field but sadly most of the journals are subscriber only and expensive. J Med Chem tends to be the best and the cheapest if your particular institution has access. Oh and thanks for suggesting I was open minded. Much appreciated.

    I think though that a few people have misunderstood my point. I am agreeing that properly published data is the only way to go. On the other hand consensus is simply a majority view which can often turn out to be incorrect. There is no need to be so defensive. I also accept that the consensus could be correct but that is exactly why it should be tested. It’s a little sad though that my scientific integrity is being challenged when I am actually doing using the scientific method. Generate hypothesis. Test to generate data. Check hypothesis, revise and tests again. And keep going round that loop. But being part of or not of a consensus view is not in the scientific method. It is a view that is shared but has no actual scientific value in the end. As I think Our Nobel prize winner above demonstrate.

    I accept that the climate is changing, I just query whether this can be quantified with any certainty in a computer model without the experiment being done. Personally, as somebody who spends a considerable amount of time doing experiemnts in the lab I am uncomfortable with the level of experimentation that is being done (that is a personaly opinion that you are free to ignore). I find it tiring that this gets reduced to a slanging match and people get characterised as right wing oil lovers. This is a scientific debate and I am trying to give you an indication of my experience as an end-user of models.

    I actually sit right next to our molecular modeller at work. We’ve spent the last 4 years trying to understand exactly how our drugs are working on a molecular basis. This type of thing is supposed to be pretty well understood from a scientific point of view, but for 4 years we’ve got nowhere. The models gave a plausible and self consistent answer but when we subsequently tested it further they always failed. Eventually, what was happening was revealed to us in a crystal structure and all our ideas and models were wrong. It turns out that the protein rearranged itself to accomodate the drug; the so-called induced fit method. At which point we realised why 4 years of comupter modelling and testing ahd got us nowhere. My point is that sometimes nature does things which simply cannot be predicted by modelling. It’s not a freak event or the hand of God or any such nonsense. It’s that sublte interplay of biology, chemistry and physics that cannot be explained until after(!) you’ve had the eureka moment or that one piece of data. That is the nature of real wet dirty science. Models are great but they are no substitute for the real thing.

    So sorry folks, I think the models are still likely (in my experience) to be wrong and possibly by some margin. But keep going, please, becuase it’s quite clear that something is happening and so it’s important to keep testing the hypothesis. I am skeptical, yes, but I respect the difficulty of the work. I did not intend to suggest that the work was bogus. I just come at this from a different angle and with a different experience of models. I had just hoped that it might be valuable for one discipline to hear the experiences of another and maybe go away and reflect. For me I have found this site to be tremendously valuable and I’ve learned a lot. I’d hoped that might be a two way process.

    Over to you….

  49. guthrie:

    #11, Keith- I’d love to have a second earth to experiment upon, but the ethical protocols preclude me sentencing 7 billion humans to be experimented upon. (Not to mention the lack of a second planet)

    So, since your gold standard is physically and ethically impossible, are you prepared to accept the physical experiments on infra-red absorption of CO2, and on other parts of the physics of the climate? Then, if you accept them, will you accept 20 years worth of modelling that is trying, and apprently succeeding in continual improvement?
    What would convince you that they can model 50 years ahead in climatology with worthwhile accuracy?

  50. David Thorpe:

    I don’t know if you’ve come aross tis hoax perpetrated on scientifically illiterate contrarians in the last week?

    I was interviewed for BBC World Service’s Newshour last night about it – which you can listen to for a while on their website (the 20.00 hrs edition, about 20 minutes into the programme).

    Two points I made especially: I wish the sceptics would spend more time looking at the evidence for global warming and not waste their time with conspiracy theories: there aren’t any. And the writer of the hoax is anonymous because we may be thinking of another. Our message is – look carefully at the evidence.

    It is also talked about on today’s blog at http://lowcarbonkid.blogspot.com/

    In case you missed the hoax, it’s written up here: http://commentisfree.guardian.co.uk/david_thorpe/2007/11/wishful_thinkers.html

  51. Chip Knappenberger:

    Gavin,

    Maybe you could explain how this was calculated (from the “response” to “sceptic argument 1″:

    Globally, there is a warming trend of about 0.8C since 1900, more than half of which has occurred since 1979.

    A linear trend from 1900 through 2006 of the HadCRUT3v data (since this was the BBC, I’ll assume this was the dataset employed) indeed yields about 0.8ºC of warming (0.764, actually). Since 107 years went into the linear calculation, and since 28 of those years are from 1979 to 2006, then 28/107=0.26, or about 26% of the rise has been since 1979. If you fit a second order polynomial through the data from 1900 to 2006, you also get an overall rise (as measured as the difference between the 2006 fitted temperature and the 1990 fitted temperature of about 0.8ºC (0.766, actually), about 36% of which comes in the period 1979-2006. So where exactly does the value “more than half” come from? Surely the overall change from a linear fit from 1979-2006 (~0.49ºC) cannot be compared to the overall change from a different linear fit from 1900-2006 (~0.8ºC)—this would ignore anything that happened in the middle (think 1.5 cycles of a saw-tooth as an extreme example)!

    Also, re: your response to comment #45, the same HadCRUT3v data shows that through September, the average global temperature anomaly for 2007 ranks 6th all-time, I would hardly characterize that as “on-track to be the 2nd warmest year on record” (unless you know something that I don’t about temperature during October and November!).

    -Chip Knappenberger
    to some degree, supported by the fossil fuels industry since 1992

    [Response: I know of your penchant for linear trends, but your claim about the warming since 1979 based on a linear fit since 1900 is, umm, odd. GISTEMP will have 2007 as the second warmest year - I'd do the trends but the server seems to be down. The difference between HADCRUTv3 and GISTEMP is likely to be in their assessment of Arctic trends - included in GISTEMP but not in HADCRUTv3. - gavin]

  52. Keith:

    Guthrie, I actually pointed out the obvious difficulties in doing the forward experiment so your point is fair. Ethically, I guess we’ll need to find a rodent populated earth AND non-rodent, non-human one. Think that might be tricky :-)

    Seriously, (sort of) my guess would be to do some kind of box experiment where we try to creat a small scale earth in a sealed environment. Obviously, this is prohibitively expensive as well as quite a challenge from an experimental design point of view but it migth be possible. In fact, if one were to be able to have two (hey what the hell!) then you could test forcings in dulpicate or with a negative control. But this is fantasy at this stage. I guess what I’m trying to say is that perhaps a more even handed view of models should be considered. Less black and white. But I understand the difficulties in doing that since the more irrational skeptics will sieze on the smallest chink in the amrour as a means of saying the whole thing is wrong. So, you are right that I’m going to have to make do with the models for now until a realistic experiment is designed.

    I’m afraid, though, that my experiences as a medicinal chemist mean that I’m quite battle scarred as far as models go and there’s not much you can do to convince me that we should soley rely on a model for our output. We’ll just have to disagree on that one.

    And in 50 years time we can see who was closest to the truth.

  53. SecularAnimist:

    gavin wrote: “So why do the contrarians still use arguments that are blatantly false?”

    First of all, their audience is not scientists, it is the general public.

    Second, their purpose is not to establish the truth, it is to keep the public sufficiently confused about the reality and/or seriousness of anthropogenic global warming that the public will not demand urgent action from governments and corporations to address it by pursuing a rapid phase-out of fossil fuels, which would reduce the trillion-dollar profits of the fossil fuel corporations.

    For twenty years and counting they have been very successful, and continue to be successful in the USA, as demonstrated by the energy legislation now before the US Congress, where legislators are about to remove most support for efficiency and renewable energy — including the existing tax credits for solar and wind — and maintain subsidies for the fossil fuel industry.

    You may be familiar with the “big lie” theory of propaganda: repeat a lie (and the bigger and more audacious the lie the better) over and over again, and people will come to believe it is true just because they have heard it so many times.

    There is an element of that in the propaganda of the climate change deniers, and it has been very effective. That’s why you repeatedly encounter the same thoroughly debunked lies over and over again, coming from “grassroots” climate change deniers like those who post comments here. What’s important is not providing a “coherent” story, but simple repetition of the same scripted talking points over and over and over again, until “everyone knows” things that aren’t true.

  54. SecularAnimist:

    Keith wrote: “And in 50 years time we can see who was closest to the truth.”

    There is already more than enough empirical evidence from actual observations of what is actually happening to the Earth’s climate and biosphere right now as a result of anthropogenic warming to “see who is closest to the truth.” If you are uncomfortable with models, then take a look at the empirical evidence. If anything it is more alarming than the models.

  55. Carl:

    Re:39
    It’s “lunacy” because that curve does not represent the history of the global mean temperatures to the best of our current knowledge. It’s a cartoon with a mix of correct data (probably volcanic eruptions), spurious data (global temperature) and ad hoc curve fitting.

  56. Jim:

    Re #12

    Glen, I’ve made the same comment several times.

    The expected rapid warming in the early part of the 20th century might have been diminished by the global dimming aerosols. Only now with that problem being reduced is the true solar effect being felt.

    I’m not one to say “It’s all the sun.” I think there is still a big GHG effect. However, we can’t use GHG to explain the Medieval Warm Period (even if it wasn’t as warm as it is now) so variations in solar output is used to explain it. Yet somehow mysteriously with all of the solar proxies indicating similar solar activity now as during the MWP apparently this time the sun is declared to have almost no effect on the warming.

  57. John:

    #45
    Gavin – thanks for the reply … but we need to get this straight … from the UK met office global surface T database you can go and read the data.

    http://hadobs.metoffice.com/hadcrut3/diagnostics/global/nh%2Bsh/index.html

    I’ll list the global surface T averages last 10 years (anomalies above the 61-90 mean) :
    1998 : 0.515
    1999 : 0.262
    2000 : 0.238
    2001 : 0.400
    2002 : 0.455
    2003 : 0.457
    2004 : 0.432
    2005 : 0.479
    2006 : 0.420
    2007 : 0.441 (thru September)

    Now given that the October 2007 global sea anomalies (from HadSST2) are the lowest since December 2000 (and for the southern hemisphere its the lowest since 1995) I think we can expect the 2007 average figure to drop lower by year end.

    So some observations on this, that anyne can see :
    - 2007 will be 4th or cooler (not second)
    - temperatures have been basically flat since the IPCC 2001 report.
    - and if you plot these numbers on the 2001 IPCC graph (which you can see on p34 of the SPM) you will see they fall below the whole range of model predictions. Why can’t we just admit it – we didn’t properly articulate the range of uncertainty in 2001.

    Now as scientists I can see why we get frustrated that we are unable to convince people more fully. I get it. For those of us that genuinely believe there is a problem we are in a terrible bind. We are caught betwen our intellectualism and our humanity. We can’t be both right AND give out good news. For the rest of the world this is all great news – its no wonder we can’t get people to sell their SUV’s and stop flying in planes. People aren’t stupid – they can read graphs too.

    And if you stand back from the details and see whats happening now – respected scientists standing up and saying “we may be wrong”. And its right to say that …but what do we is fora like this – we belittle, we condescend and we are arrogant. Is it so hard to say that we will all be much better off if we are wrong ? And say we might be.

    [Response: As I mentioned above, 2007 will #2 in the GISTEMP record - but regardless, IPCC and all climate model projections are for the long term forced trend - not the value in any one year. The std. dev. about the trend for any model run or the real world is around 0.15 deg C and thus even with the HADCRU numbers the 2007 temp is well within the expected range. IPCC has never made any statements that concern the expected annual numbers (they have always discussed long term trends), and so your comment about 'our' failure to communicate makes no sense. The rest of your comment is simply bizarre (respected scientists standing up?): I do not suppose to speak for you, and you should not suppose to speak for me (or IPCC). I, and they, can speak for ourselves. It would indeed be better if AGW was not a problem but wishing it, don't make it so. - gavin]

  58. Nick Gotts:

    re #51 Keith “Seriously, (sort of) my guess would be to do some kind of box experiment where we try to creat a small scale earth in a sealed environment.”

    That would surely be just another kind of model, in something close to the sense that term is used in biomedical science: “an animal model of depression” or whatever. That is, your proposed “small scale earth in a sealed environment” could give useful information (whether enough to justify the effort and cost is another matter), but there could not be, any more than there is with computational models, any guarantee that the experimental system included all the important properties of the target system. Indeed, I can already almost hear the sceptics/denialists/contrarians pointing out all the ways the two differ, and why results for the experimental system tell us nothing whatever about the target system.

    The basic atmospheric physics of greenhouse gases is well-understood and experimentally validated, so if increased CO2 is not causing a rise in temperature, we need a mechanism to prevent it doing so (and no plausible mechanism has been proposed). The computational models we have can reproduce specific features of past behaviour, and have been used to make pretty good predictions years ahead. There are good criteria (see a recent inline, by Gavin I think, on the “Is the ocean carbon sink sinking?” thread) for which aspects of these model outputs we should regard as highly likely to hold, and these aspects include crucial ones such as the anthropogenic role in recent warming, and the approximate value of the sensitivity parameter (for which there is independent evidence from past climate changes). If these models are anywhere near right, action is urgent. Tell me Keith, is there any reason why anyone should give anything like as much weight to your anecdote about models in chemistry not always giving the right answer (hardly a surprise to anyone who has done computational modelling of any kind), as to the considered views of the vast majority of climate scientists, as expressed in the relevant scientific literature?

  59. John N-G:

    #48 Keith – Many an interesting interdisciplinary discussion has foundered on the different meanings of the word “model” among the disciplines. Let’s see if we can find the analogues between your models/experiences and ours. Correct me if I mischaracterize yours.

    Your colleague’s model was fundamentally based on molecular structure and was found to be wrong because it made an invalid assumption: that the molecular structure was static. Thus it was invalid at its core.

    The core of climate models is the laws of physics governing the behavior of the atmosphere and the oceans. These aspects are “unlikely” to be invalid.
    But where the laws of physics let us down are the processes that cannot be simulated in that way with present models, because they are too small (convection, cloud microphysics, etc.) or indescribable through fundamental laws (climate-biosphere changes) or because we don’t know how to properly describe them (ice sheet dynamics). These areas (of parameterization) are the primary source of climate model uncertainty.

    Because we can’t run the experiment on a parallel Earth, we deal with the uncertainty in multiple ways. First, the models are tested to see whether they accurately describe today’s climate. Second, the models are tested to see whether they accurately describe past climate change. Third, many different research groups create their own models, using a variety of different assumptions in the parameterizations (while these don’t necessarily span the range of parameterization uncertainty, they give a sense of the sensitivity to parameterizations) and the Hadley Centre, for one, has begun running ensembles of simulations using a range of plausible parameterizations. Work on model validation and parameterization continues vigorously to this day.

    We can only check the validity of these things for present and past climate, so as CO2 kicks us into a climate situation for which there’s no prior reliable data, the uncertainty in the modeling output grows (for example, what if most of the Arctic sea ice goes away in the next decade). But the fundamental physics will not change (the CO2 molecule will not change shape and alter its radiative characteristics), so the average of the projections of the variety of climate models that have been validated against past climates is still the best guess for the future. The uncertainty is a fundamental part of that projection, and there’s no basis to think that the smaller-climate-change tail of the distribution is any more likely than the larger-climate-change tail.

  60. Rikard:

    Gavin, thanks for your answer. I looked at Nir Shavivs webbsite and at Ahluwalias paper. First, Nir Shaviv gives other solar proxies (10Be and averaged sunspot numbers) that apperently peaks in the late 1990s just as the juxtaposed neutron count. Is he at fault?

    Secondly, while I agree there is uncertainties in the neutron count, I disagree that the Yakutsk series shows no trend. Clearly, the trend is a flat high level in the 60:s and early 70:s and down in late 70s to 90s. And the correlation in the overlapping period was striking. Is there more or other data available to refute the connection of 10 GeV cosmic rays and temperature?

    [Response: None of the continuous records of cosmic rays show a recent upward trend. 10Be doesn't either - the Dye 3 record he shows has a trend in the earlier part of the century, but the South Pole record is flat - both of them cannot be a correct representation of the 10Be production - but in neither case is there a continuing trend. The discussion about which energy cosmic rays is irrelevant since the modulation of GCR at all energies is governed by the solar magnetic field. Which is the reason why they all correlate with the sunspots of course. There is no theory that allows for one kind of GCR to increase while all the others stay flat. - gavin]

  61. cce:

    Re: 39

    In addition to the points from #55, did you look at their graph of temperature from 1880? It’s a bit . . . strange. Where are they getting this stuff?

  62. J.S. McIntyre:

    re 52

    “Seriously, (sort of) my guess would be to do some kind of box experiment where we try to creat a small scale earth in a sealed environment.”

    They tried something like that in the Arizona Desert (though it was focused on reproducing a closed biological system). The first go of it didn’t work too well, though it looks like the University of Arizona has taken it over…

    http://en.wikipedia.org/wiki/Biosphere_2

  63. guthrie:

    KEith, the small problem is that we can’t wait 50 years to see which is correct. If we do, we’ll run out of time to do anything about it.
    So at the very least, we can encourage efficiency measures and spend money on technological improvements, because these will be gains for us even if it turns out (somehow) that global warming is all the suns fault and starts going into reverse.

  64. Chip Knappenberger:

    re: 51

    Gavin,

    I only threw out a couple of possibilities of how one may calculate the temperature changes over different time periods. Since you helped edit the article, I am wondering what sort of analysis shows that “Globally, there is a warming trend of about 0.8C since 1900, more than half of which has occurred since 1979.” No apples-to-apples comparison that I could come up with (linear or polynomial using the HadCRUT3v data) gives that answer.

    -Chip

  65. Barton Paul Levenson:

    Timo writes:

    [[The reason why I am a “sceptic” is because my gut feeling says that humans aren’t able to change course of Nature.]]

    It’s better to rely on empirical evidence than on gut feeling.

    [[Mother Nature is indifferent and will take its own course, irrespectively what humans will do trying to change that. Mother Nature is too big to fight against.]]

    “Too big” is a quantitative term. How big is Mother Nature compared to us, and what index are you using to compare them? Where global warming is concerned, here’s an interesting statistic for you — 38% of the carbon dioxide in the air has been added by artificial processes.

    [[The most disturbing thing is the secretiveness regarding data, methods, codes and other information. If scientists are reluctant or completely unwilling to share this information which others, I am becoming suspious. If I (or others) am not allowed to analyse data and methods, how should I be convinced that you are right and I am wrong.]]

    All the information you want is publicly available, but to learn it you have to put in a little study time. Nobody is trying to conceal anything. If you want raw data, try the NASA GISS or NOAA or Hadley Centre web sites.

    [[By the way: I am living in the Netherlands, close to the coast and a couple of meters below sea level. And I am not really concerned about disastrous sea level rise]]

    Maybe if you lived in Bangladesh…

  66. Keith:

    Nick. Thanks for the eloquent reply. Yes, I think the analogy you suggest is exactly correct. I’d see the small scale earth experiment as being similar to an animal experiment. And you are right that that is also somewhat unsatisfactory. However, I believe it to be far superior to a virtual experiment. From my perspective, we simply aren’t allowed to put a drug anywhere near a human until it’s been in animals. Nobody is allowed to use a the results of a comuptational experiment as a means of justifying that a compound is dosed in man. The sequence tends to be: test compound in cells, computationally decide which ones look good according to a parameter set and then go into animals before we go to man. The computers tend to be used to reduce numbers to more manageable and cheapers levels in a “rational” fashion.

    As for whether my anecdote should carry any weight, well induced fit has been seen in other systems, particularly protein kinases. And I you’d find a number of medicinal chemists with even dimmer views on our ability to predict anything. I doubt you believe that. But it sounds like you think I am some kind of right wing crank or fake and I see no logical way of disproving that over this forum.

    For induced fit see

    http://jb.oxfordjournals.org/cgi/content/abstract/140/3/305

    It’s quite common and unpredictable. Protein folding is one of life’s great mysteries and has yet to reveal it’s secrets. We certainly cannot take an amino acid sequence and genuinely predict strcuture and function. You’d think that we could, the molecular forces are well understood, but we’re often wrong.

    See

    http://pipeline.corante.com/archives/2007/10/29/what_we_dont_know_about_enzymes.php and follow the link to Reetz’s paper.

    Actually, Derek is well regarded and has much to say about the problem in my field with modelling. Just opinions though that come from experience. See

    http://pipeline.corante.com/archives/in_silico/

    But feel free to ignore my anecdote. It won’t get published for ages anyway. Legal departments get in the way of that sort of thing.

    John NG. Thanks. You are right that initially we did assume that the protein was static. That’s what most people had seen with this particular protein. Then, another group published a new structure 2 years ago showing a large domain movement. This new structure also failed our molecule, but it did make us look much more at protein mobility. It’s one of the big problems in this particular field but there are models available to computationally move the protein systematically. However, the calculations are substantial when you take into acount the total number of conformations for an amino acid and then try to attach them together. It HAS ben done but it’s one heel of an undertaking. And, yet again that failed. The reality was that the changes were subtle; most of the protein stayed unchanged but 3 moved and he presto, a working drug. So I’d say that the hypothesis was not invalid. We’re looking at well characterised physical processes; van der waals, hyrdrogen bonding, entropy, solvation and so on. This is hardly new.

    I’ll give you a new analogy that I mentioned earlier. What we do is very very expensive and the further you go the more expensive it gets ($1bn pre drug and counting). So what we try to do is predict what compounds are going to make it through the process. Like climate change we have a whole host of factors to consider with varying uncertainties. Some are easy to fix, like solubility or logD and others like toxicology are a bit more difficult. So again there are similarities with climate change. And to be honest, we get it wrong a great deal of the time. Drug attrition rates are pretty terrible. 1 in 10 compounds will make it through Phase III (we’re maybe 7-10 years in to the project by then!). There’s a hell of lot of chemistry and biology to consider in climate change and I doubt if anybody has much of a handle on that bit given our own experience. If you doubt this particular situation I suggest you check out Pfizer who have lost a couple of compounds late in the day and immense expense. And Pfizer love their models so you can bet that there were green lights across the board before it tanked. So experiments backed up with models failed, pretty spectacularly. Makes you think?

    We too generate models using historic datasets. We split it in two, generate the model and then see if it fits the unused dataset before going forward. We do the sensible stuff and check the r2s and everythign looks great. And more often than not these models break down very quickly. It’s worth pointing out that they very often work at the start but then start to fail as you get outside the area you started in (which is maybe where I see the issue with climate models breaking down but that’s my own view). We’re doing very similar stuff to yourselves. I could go on here about how models often don’t work very well but I’m getting tired of this to be honest.

    Perhaps I could turn to your field for a second to give another example of where things can change in unpredictable ways in science. Ozone layer depletion. Well understood right? Well, sort of. Turns out that chlorine peroxide which has long thought to be the main culprit doesn’t do what it’s supposed to according to the theory. I t should be reactive and short lived. Eh. It isn’t and it’s pretty clear now that the mechanism (not the resutl I might add!) of ozone depletion is in need of a rethink. See

    http://www.nature.com/news/2007/070924/full/449382a.html

    I actually think this is a fantastic piece of work. A really good scientific puzzle that need to be looked at. But it goes to show how even apparently well understood processes turn out to be more complicated.

    So don’t be surprised if some of the basic processes in climate change turn out to be a little more complicated than you thought. I admit I could be entirely wrong and you might be absolutely correct but it is good for the scientific community to keep testing its hypotheses.

    Now, I truly believe the work that you are all doing is top notch. Peer reviewed by the best minds out there. But please excuse me if I’m just a little skeptical of them and their accuracy.

  67. Barton Paul Levenson:

    Keith writes:

    [[Let me start by saying that I’m a organic chemist working in the drug industry and work at the interface between biology and chemistry. So I have perhaps an interesting view on all this.

    Let’s start with the consensus thing since that’s easy to dismiss. Having a consensus view is not a scientific proof. A consensus opinion in science is a herd mentality. It’s poor science.]]

    It’s hard to believe you’re “a organic chemist” [sic] if you don’t know how to distinguish the scientific consensus on a subject from a “herd mentality” and think science has anything at all to do with “proof.”

    Do you also think it’s a “herd mentality” (and thus, presumably, unreliable) that scientists believe relativity is true? Or quantum mechanics? Or evolution?

    [edit - please no ad homs]

  68. Keith:

    Guthrie. Spot on. I agree. Energy conservation and sensible use of resources is fine. I just support that because resources are finite and I hate watching the natural world being ripped down or polluted. Just because I query the models and so forth doesn’t mean that I want to drive around in SUV. So perhaps we can fianlly agree on something eh….

  69. Barton Paul Levenson:

    Michael writes:

    [[Gavin, what is your response to the idea that climate science is in its infancy?]]

    Wasn’t it Louis Agassiz who confirmed that there was once an ice age, way back in the 19th century? (Now, of course, we know that there were many ice ages.) And Jean-Joseph Fourier who posited the greenhouse effect back in 1827? Quantum mechanics, by way of contrast, is a hundred years younger (to the year if you go by Werner von Heisenberg’s 1927 work). No doubt there’s a lot more to learn about climate, but the field is hardly in its “infancy.”

  70. Timo Hämeranta:

    To 11. Keith:

    You are right, and honest modellers have now admitted that they are unable to predict anything sure for decades to come.

    Please see e.g.

    - IPCC AR4 2007 WGIII SPM, last sentence:
    ”the future is inherently uncertain”

    Cox, Peter M., and David B. Stephenson, 2007. A Changing Climate for Prediction. Science Perspective Vol. 317, No 5835, pp. 207-208, July 13, 2007

    Smith, Doug M., Stephen Cusack, Andrew W. Colman, Chris K. Folland, Glen R. Harris, and James M. Murphy, 2007. Improved Surface Temperature Prediction for the Coming Decade from a Global Climate Model. Science Vol. 317, No 5839, pp. 796-799, August 10, 2007, online

    Stainforth, David A., M.R. Allen, E.R. Tredger, and L.A. Smith, 2007. Confidence, uncertainty and decision-support relevance in climate predictions. Philosophical Transactions of the Royal Society A Vol. 365, No 1857, pp. 2145-2161, August 15, 2007

    and finally:

    Green, Kesten C., and J. Scott Armstrong, 2007. Global Warming: Forecasts by Scientists versus Scientific Forecasts. Energy & Environment, draft September 8, 2007, online

    “We audited the forecasting processes described in Chapter 8 of the IPCC’s WG1 Report to assess the extent to which they complied with forecasting principles. We found enough information to make judgments on 89 out of a total of 140 forecasting principles. The forecasting procedures that were described violated 72 principles. Many of the violations were, by themselves, critical.

    The forecasts in the Report were not the outcome of scientific procedures. In effect, they were the opinions of scientists transformed by mathematics and obscured by complex writing. Research on forecasting has shown that experts’ predictions are not useful. We have been unable to identify any scientific forecasts of global warming. Claims that the Earth will get warmer have no more credence than saying that it will get colder.”

    To Gavin Schmidt: my current position is as follows:

    “So far, we have to wait at least to the 2010s to see whether the sceptics or the ‘mainstream’ scientists are right.

    The IPCC modelers are hoping to include biosphere correctly in their models only in the next report 2013, and perhaps thereafter properly the internal variations, clouds and extraterrestrial influences….

    I suspect we have to wait for definitive answers still more, obviously to the 2020s.

    It’d be honest and fair when all the debaters admit huge uncertainties still remain and concerning actions to tackle climate change it’s all about precaution only.

    I have nothing against precaution, but I call it precaution, and not a proven scientific fact.”

    Cheers

    [Response: But a decade ago, people (you?) said the same thing. Meanwhile, the planet has continued to warm at the rate predicted. And yet apparently the 'answer' is still a decade away. In fact, if you are so open-minded, what about this document you wrote only 3 years ago? In it you definitively claim that "CO2 does not drive climate", "there is no polar amplification" etc. No uncertainties there! - gavin]

  71. steven mosher:

    he mailed out a questionaire to 61 people.

    “Fourteen of the group filled in the questionnaire”

    Milloy’s stunt was utterlyand stupendously pathetic. I was glad to see you expose it’s stupidity. Sad that you link something exclipsing Milloy’s junk.

    This is as retarded as the Milloy piece and if you recognized the stupidity of the latter it is merely craven not to recognize the stupidity of the former.
    This is worse than attacking a stupid editor in Ely for his math error while excusing Gore for his error about
    “evacuating” island nations.

    Having hung around in the halls of the sceptics for some time I can tell you there is no consensus whatsoever. NONE. Every time I listen to another sunspot nut I want to stick knitting needles in my eyeballs. Figuratively of course. At some point perhaps a taxonomy of sceptical concerns and sceptical aproaches would be helpful. Some scepticism is mere obsfucation.
    Some is methodological. Some is ignorance.

    Anyway, I’m sceptical that a poll of 61 sceptics has any value whatsoever, except as a pretext for an article. Funny, the author didnt discuss ODEs

  72. dhogaza:

    I’m afraid, though, that my experiences as a medicinal chemist mean that I’m quite battle scarred as far as models go and there’s not much you can do to convince me that we should soley rely on a model for our output.

    Why do you think climate science relies solely on models?

  73. Ray Ladbury:

    Rikard,
    Galactic cosmic rays cause upsets in memories, etc. on satellites. Folks in my field have been following these since the ’70s–no clear trend–lots of fluctuations, but no trend. The other thing to keep in mind is that the mechanism proposed for this “forcing” is, to say the least, speculative. It effectively tries to explain the unknown in terms of the unknown–hardly scientific. Greenhouse gas forcing is well understood and well established. Indeed, if we were to find GCR forcing were important, it is unlikely that the forcing due to CO2 would be the parameter to give. Rather, you’d probably see adjustments to aerosols or some other forcer that we don’t know as well. Given this fact, I don’t understand why you would adopt the speculative over the known.

  74. wayne davidson:

    #53, Contrarian audience is mainly for politicians who should rely on the best science possible before tackling any given problem. Climate science is of course marred by their contentions. The plan is plant doubt, a bad weed which slows down considerably any possible action. The vast majority of people, who actually enjoy the outside world, have noticed for themselves that something is strange with their climate, any contrarian trying to convince them otherwise looks like a snake oil salesman.

  75. John Mashey:

    Keith:
    You are over-generalizing from experience with the limits of one kind of modeling and applying it to others where you may not have first-hand experience. Some problems in molecular biochemistry modeling are *way harder* than those involving physics & chemistry properties in bulk.
    [I used to help design and sell a lot of computers used in modeling, including mechanical, weather,climate, molecular, and medical.]

    If you turn your thermostat up, it’s fairly easy to predict that the average temperature will rise, and this doesn’t need computer models at all.
    It’s much harder work to do a fluid dynamics and radiation model of your house, and predict the exact temperature rise in each part of the house, and bound the uncertainty. That does take computer modeling.

    Nobody tries to model the future location of every O2 molecule in the house.

    1) I recommend:
    Supercomputing and the Transformation of Science (Scientific American Library)
    by Kaufmann and Smarr. (very cheap from Amazon, and a beautiful book). Even though it’s old (~1993), and there’s been a lot of progress, the models of that era were already plenty good enough for useful work.

    2) If you generally distrust computer modeling:
    a) Do not ride in a modern car.
    b) Do not fly in a modern airplane.
    c) Stay our of newer big buildings and off newer bridges.

    3) Historically, for each problem, the state of modeling evolves:
    First, no one can build a computer model that is very useful.
    Second, there is enough science and enough resolution (if a gridded problem) to start getting useful results.
    Third, as the science and/or the resolution improve, the results keep getting better.
    Fourth, at some point, the results are good enough that one has encoded all of the relevant science well enough, and has enough resolution, that one need go no further.

    But, the progress varies by discipline. Some mechanical-engineering problems were in good shape by the early 1990s. They even got inexpensive enough to get excellent results by the mid-1990s, such as crash codes for modeling automobile crashes.

    Physics modeling generally has a longer practical history than biochemical, and especially medical. Some of the latter problems are really hard.

  76. Ray Ladbury:

    Keith,
    You appear to have some misconceptions regarding both models and the scientific method–particularly as it relates to the physical sciences. The example you quote re. H. Pylori and Ulcers is an example of a success of scientific consensus rather than a failure. The fact is that there was fairly strong evidence establishing stress as being associated with ulcers. There was little evidence to begin with establishing causation by H. Pylori. It took time to accumulate the evidence, so it took time to change the consensus. Where’s the problem.
    WRT anthropogenic causation of climate change, the situation is quite different. Here there is no other hypothesis that has any support from the available evidence. There are multiple independent lines of evidence establishing the value of CO2 forcing at ~3 K/doubling. And the greenhouse effect has been known since the mid 1800s and understood in its modern context since the 1960s. As I said above, if you were to discover a new forcing mechanism, the thing to give would probably not be the magnitude CO2 forcing, but some portion of the theory less well understood–e.g. aerosols.
    Skeptics love to quote George Box, who said, “All models are wrong.” They forget that he went on to say,”Some models are useful.”
    Climate models are useful because they can be used to bound the amount of change we can expect, and therefore the risk and the level of mitigation that is appropriate. Climate models are the only bulwark against alarmism. The fact that we are warming is indisputable. There is no credible dispute to the attribution of that warming to anthropogenic causation simply because there is no credible alternative mechanism in terms of known physics. This in no way requires any validation from models. All the models do is show that indeed anthropogenic ghg are a sufficient cause and establish a guide for what to expect in the future.

  77. Aaron Lewis:

    Re # 11
    Scientific Proof? No such thing! Good scientific theories make predictions that can be tested; their predictions have been tested; and the theories make predictions that can be used with confidence. For example Newton’s Law of Gravitation works very well at low speeds and is easy to use. At higher speeds, predictions made by the Theory of Relativity are closer to observed results. Neither theory has been “proved” except that each has been tested many times; and, with some care, one can have confidence in each theory’s predictions. The old theory about stomach ulcers did make some useful predictions; the new bacterial theory makes more useful predictions.

    AGW has made predictions that were sufficiently close to observed conditions that many scientists feel that other predictions by the AGW theory are much better than those made by any other theory, model, astrologer, priest, or the Farmer’s Almanac! Is AGW proven? No more than the Law of Gravitation is proven! Is it the best we have? YES! Is it useful? YES! Is it going to get improved and changed so that it can make better predictions? YES!

    Can we have confidence in AGW’s current predictions? Maybe. Perhaps due to social pressures, the full impact of the AGW Theory has not been communicated. What we have here, is a failure to communicate!

    Of course there are skeptics and deniers out there. There are still people that want creationism/ intelligent design taught as science!. When a substantial part of the population reject a scientific theory as powerful and useful as Evolution, we cannot expect all of the population to accept a theory as complex as AGW. Nor, can we expect better science education as long as we have a president that accepts intelligent design as a “scientific theory” (rather than as religious teaching.)

    The full impact of AGW is not going to be communicated until we have a POTUS that takes science seriously. We are not going to have real action to combat or mitigate global warming until the full impact of AGW is communicated.

  78. Richard Ordway:

    Keith,

    Thank you for your references and clearing up the spelling.

    Some thoughts on the global warming (climate change, climate distortion, global change) scientific consensus and opinion:

    From: Peer-reviewed Journal “Science”: “The Scientific Consensus on Climate Change.”

    “The scientific consensus might, of course, be wrong. If the history of science teaches anything, it is humility, and no one can be faulted for failing to act on what is not known. But our grandchildren will surely blame us if they find that we understood the reality of anthropogenic climate change and failed to do anything about it.

    Many details about climate interactions are not well understood, and there are ample grounds for continued research to provide a better basis for understanding climate dynamics. The question of what to do about climate change is also still open. But there is a scientific consensus on the reality of anthropogenic climate change. Climate scientists have repeatedly tried to make this clear. It is time for the rest of us to listen.”

    “The scientific consensus is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC). Created in 1988 by the World Meteorological Organization and the United Nations Environmental Programme…”

    “IPCC is not alone in its conclusions. In recent years, *ALL* (emphasis mine) major scientific bodies in the United States whose members’ expertise bears directly on the matter have issued similar statements.”

    http://www.sciencemag.org/cgi/content/full/306/5702/1686

    From Wikipedia:

    For groups endorsing the GW peer-reviewed science:

    “Contents
    1 Statements by concurring organizations
    1.1 Intergovernmental Panel on Climate Change (IPCC) 2007
    1.2 Joint science academies’ statement 2007
    1.3 Joint science academies’ statement 2005
    1.4 Joint science academies’ statement 2001
    1.5 U.S. National Research Council, 2001
    1.6 American Meteorological Society
    1.7 American Geophysical Union
    1.8 American Institute of Physics
    1.9 American Astronomical Society
    1.10 Federal Climate Change Science Program, 2006
    1.11 American Association for the Advancement of Science
    1.12 Stratigraphy Commission of the Geological Society of London
    1.13 Geological Society of America
    1.14 American Chemical Society
    1.15 Engineers Australia (The Institution of Engineers Australia)

    2 Noncommittal statements
    2.1 American Association of State Climatologists
    2.2 American Association of Petroleum Geologists (AAPG)

    3 Dissenting statements”

    Wikipedia-

    http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change

    From RealClimate.org:

    http://www.realclimate.org/index.php?p=86

    http://www.realclimate.org/index.php?p=80

    My other thought on this is that, when I went to the US pubmed.gov and typed in “peptic ulcer”, there were 3683 published papers on peptic ulcers starting with the date 1904 “Peptic Ulcer of the Jejunum.” Since it was, you say, a consensus, people did not seem to be examining alternatives very much.

    In climate change, however, even before a consensus, there has been a mad scramble around the world since the 1970s at least, to disprove GW with almost unlimited funding from the oil coal, gas and transportation industry in the peer review system.

    In the peer-review literature, there is simply no contrary evidence to global warming that stands up in the literature going back to 1824 (1824 “MEMOIRE sur les temperatures du globe terrestre et des espaces planetaires” in the Annales de Chimie et de Physique) (Jean Baptiste Fourier-Academy–Mémoires de l’Académie Royale des Sciences de l’Institut de France VII. 570-604
    (1827)Http://www.wmconnolley.org.uk/sci/fourier_1827/fourier_1827.html#text (Photocopies of orginal text)
    and continuing with John Tyndall (Heat as a Mode of Motion) (1863http://gallica.bnf.fr/ark:/12148/bpt6k559569

    MIT and the University of Virginia climate scientists (Lindzen and Michaels) have made careers of deliberately discrediting the peer review science in the peer-review process …without success…as have many others.

    In other words, GW is probably one of the most heavily researched fields in recorded peer-reviewed literature…and it stands up well.

    Perhaps the final word goes to realclimate.org on this…

    “The skeptic attitude to consensus usually starts with “there is no consensus”. That’s wrong, and they usually retreat from it to “but consensus science is meaningless”, and/or “consensus has nothing to do with science”. The latter is largely true but irrelevant. The existence of the consensus doesn’t do a lot to determine what science is done; it doesn’t prevent contrary lines being explored.
    But the consensus view does come into the tricky interface between science and policy, and science and the media.”

    http://www.realclimate.org/index.php?p=86

  79. Timo Hämeranta:

    Gavin,

    we have discussed for years, we have debated and I have also defended a few of yr views, but don’t try to pretend otherwise:

    you do know I always refer to peer-reviewed studies, ten years ago, three years ago, and today.

    I’m middleman of knowledge: both neutral, ‘mainstream’, alternative, critical and sceptical studies and views.

    Contrary to yr assertion, when sometimes I have endeavored to present my personal views I always have stressed the huge uncertainties.

    So far, the following conclusion 12 years back is still valid:

    “…we interpret our results to mean that overall uncertainty about the geophysics of climate change is not likely to be reduced dramatically in the next few decades.”

    Ref: Morgan, M. Granger, and David W. Keith, 1995. Subjective judgements by climate experts. Environmental Science & Technology Vol. 29, No 10, pp. 468-476, October 1995

    Last Friday Peter Huybers correctly stated: “We should be humble about how much we know about the climate system”.

    You too, dear Gavin.

  80. Ray Ladbury:

    Anyone who describes scientific consensus as a type of “majority voting” or “herd mentality” merely casts doubt on their understanding of science. Indeed, I question whether such people even know any scientists. I have always had managers describe working with me and my fellow scientists as an exercise in herding cats. If you get 5 scientists together at a conference, they won’t be able to agree on pizza vs. Chinese. I mean most of these guys think they’re smarter than all of their peers. How in the hell would you expect them to suddenly meekly say, “Oh, everybody else says so, so it must be true?” Every scientist is competing with every other scientist for funding, for attention, for prestiege… You don’t get that being part of a herd.

  81. tamino:

    Re: #51, #64 (Chip Knappenberger)

    I am wondering what sort of analysis shows that “Globally, there is a warming trend of about 0.8C since 1900, more than half of which has occurred since 1979.”

    Either you’re really confused, or you’re being disingenuous in order to cause confusion.

    You’re quite ignoring the fact that neither a linear nor a quadratic fit to the temperature time series comes close to capturing the actual signal. Since you seem to like polynomials, I fit a 16th-degree polynomial to NASA GISS monthly temperature data from Jan. 1880 to Jul. 2007. The result: smoothed temperature anomaly at 1900.0 = -0.2104, at 1979.0 = 0.0530, at 2007.0 = 0.5663. Of the total 0.7767 change from 1900 to 2007, fully 0.5133 occurs from 1979 to 2007. That’s 66% — well over half.

  82. CobblyWorlds:

    #39 Eric M

    Regarding the graphs at Long Range Weather, to whose defence you leap.

    Where is graph 1 (2500 – 2007) sourced from?
    i.e. http://www.longrangeweather.com/images/GTEMPS.gif
    Where comparable, it seems to me to bear no relationship to any of the 11 peer-reviewed studies that it might have drawn upon. e.g. http://www.globalwarmingart.com/wiki/Image:2000_Year_Temperature_Comparison_png

    Where is graph 2 “Global Mean Temperatures Graph since 1880″ sourced from?
    i.e. http://www.longrangeweather.com/images/gtemps2.gif
    It seems to me bear no relationship to either:
    CRU: http://www.cru.uea.ac.uk/cru/data/temperature/
    GISS: http://data.giss.nasa.gov/gistemp/graphs/ (Land Ocean Index)
    GHCN: http://lwf.ncdc.noaa.gov/img/climate/research/trends/glob_jan-dec_pg.gif

    Are you sure you’re thinking sceptically?

    Are you sure we can adapt with >6bn people to carry with us?
    (I think it’s possible we can – but we’ll lose and impoverish many on the way)

    #34 Svet
    “An intercomparison of trends in surface air temperature analyses at the global, hemispheric, and grid-box scale” Vose et al 2005 GRL Vol32.
    They state:
    “In short, the three surface temperature analyses
    depict similar rates of warming over long time scales, and
    discrepancies in recent decades are largely consistent with
    differences in methodology.”

    Cherry Picking is when you prefer without giving good cause. If you can find good reason to prefer CRU/GHCN then you may be able to draw a defensible position. However 2 points of caution:

    1) I wasted years fobbing myself off at each apparent short term abatement of the warming trend. It never came and there is no reason to expect it as far as I can see now.

    2) Pay close attention to what is hapening in each hemisphere, there’s a lot more ocean in the Southern Hemisphere, ocean damps warming because it takes a lot of energy to warm.
    GISS hemispheric plots here: http://data.giss.nasa.gov/gistemp/graphs/Fig.A3.lrg.gif

  83. Timo Hämeranta:

    When you will discuss anthrop vs natural causes of current warming, please see about the Sun:

    In summary, … it should be acknowledged that most of the Sun-climate coupling mechanisms have still not
    been incorporated into the large-scale computational climate models. Consequently, these models are incapable of handling such a complex of coupled mechanisms and are
    not able to disentangle the indirect solar contributions to climate change from each of them and might easily underestimate the Sun-induced climate change by misidentifying the primary causes of various mechanisms.”

    Ref: Scafetta, Nicola, and Bruce J. West, 2007. Phenomenological reconstructions of the solar signature in the Northern Hemisphere surface temperature records since 1600. J. Geophys. Res. – Atm., 112, D24S03, doi:10.1029/2007JD008437, November 3, 2007, online

    They conclude (contrary to the IPCC):

    “the Sun might have contributed up to approximately 50% (or more if ACRIM total solar irradiance satellite composite is implemented) of the observed global warming since 1900.”

    Further, please notice the astonishing, excellent correspondence between certain proxy temperature records and sunspot activity during the Holocene, incl. last 150 yrs thermometer data, in the new study

    Usoskin, Ilya G., Sami K. Solanki, and G.A. Kovaltsov, 2007. Grand minima and maxima of solar activity: new observational constraints. Astronomy & Astrophysics Vol. 471, No 1, pp. 303-307, August III 2007, online

    As far as I can see, climate sensitivity (i.e. 2 x CO2) is, well, still in need of more scrutiny (to put it nicely).

    [Response: None of these studies have anything to say about sensitivity - these are related to forcings, and in any case the S+W paper is methodologicially flawed (previous posts ad nauseum). -gavin]

  84. Peter McGrath:

    As one of the people who emailed the BBC link in, glad to see it got some airtime. Grapes: we have a vineyard in Leeds (53 deg 45 north), Yorkshire, England and it’s doing rather well. We could probably manage further north still but for a large belt of acid soiled uplands.

  85. Deech56:

    RE: Keith – I have read your comments with interest. I, too, have been involved in pharmaceutical research (including working in the house that Tagamet built) but in the biological realm as an investigator. The one thing I have learned is that models based on living things are shaky at best. One hears all the time that computers should be used to study living organisms (I have also been an IACUC chair), but the laws governing any given response are not well understood. I would give anything for biological models to have the predictive power of models based on physical laws like the ones Gavin works with. Throw in difference between “animal models” and the human condition and one could come away feeling that models are worthless. Unfortunately, this would be too much of an generalization.

    What one should focus on, though, is how well the models predict actual conditions. One needs only to look at the IPCC reports and the recent Hansen paper to see how well these models (some of which are decades old) done. We are living the experiment right now and we can see some of the predictions (rate of rise, stratospheric cooling, polar effects, aerosol effects). If you want to pick apart the climate models, then look at the predictions and measurements of climate, not protein folding. To infer that the climate models are incorrect because other models have failed doesn’t get us very far. But I am glad you posted. This is an excellent site with which to stay current. Maybe there can be some discussion about models in general – the good, the bad, and the ugly,

  86. Rikard:

    Referring to my earlier question on cosmic rays, do you say that the record Nir Shaviv shows (with a clear upward trend in the 20th century) is one of two sets, and the other one shows no trend? If so, are you sure that there cannot be a difference depending on where on earth you measure; cosmic rays do have a direction? (Playing devils advocate here…I just want to get to the bottom ;-)

    Similarly there are ample opportunities for a difference in variation of energies of incoming cosmic rays and hence we could allow for the possibility that more 10 GeV rays would hit the earth regardless of what the sun does?

    [Response: Different detectors have different thresholds and due to the latitude and altitude of any station, will record different amounts of GCR. The Ahluwalia records are from Cheltenham/Fredricksburg and Yakutsk - neither of which show a trend, though over the overlap period they are correlated (as they would be to any other GCR record). They do have an offset of unknown origin (unknown to me that is). In merging the two records Ahluwalia multiplied one record by a factor to get a similar amplitude change but only over the period of overlap prior to renormalising. This makes absolutely no sense and all the trend is due only to that procedure.

    If you are discussing the 10Be records, then yes, Shaviv only shows one out of two that come up to the present day (ish). This might not be his fault since he took the figure from Wikipedia which itself does not show both, but anyone familiar with the literature would know about the South Pole record - indeed there is an exchange in QSR this month on how best to interpret the different records (Mueschler et al, Bard et al, 2007). Finally, there is no evidence that the interstellar GCR spectrum has any energy dependent decadal variations. - gavin]

  87. Chip Knappenberger:

    Gavin, re your response to Comment 12:

    Not that I am advocating a solar explanation for recent temperature trends, but isn’t it rather a bit more true to say the observed stratospheric cooling is much closer to what is predicted by ozone depletion? According to Ramaswamy et al. (Science, 2006) well-mixed GHGs don’t come anywhere close to producing the recent stratospheric temperature decline. Thus is seems that your statement that “The cooling however is exactly what is predicted by GHGs” is a bit of a reach. No?

    -Chip

    [Response: MSU4 (lower strat) is mostly driven by ozone depletion, cooling in higher levels (SSU) is dominated by CO2. - gavin]

  88. Steve Bloom:

    Re #70 (TH): Timo, as I was reading your response I was recalling that it was only recently that you had a much different position. Thanks to Gavin for saving me the trouble of finding one of the many suitable smoking guns. That series of tubes sure is convenient!

    A couple of clean-up points:

    Regarding climate model predictions (in the sense of a forecast), there has only been one so far (very recently and from the Hadley Center IIRC). We’ll know how they did in about five years. I don’t know if there’s a formal distinction between what the models do (projections) and forecasts, but as I understand it the difference is along these lines: A given model is run many times to establish what the global surface temperature increase is likely to be by 2100. While the runs all land within a reasonable range of (e.g.) 3C in 2100, looking at any individual year there’s too much variation between the runs to say anything useful. A forecast, by contrast, would be based on seeing some degree of agreement between runs.

    Regarding Green + Armstrong, it’s yet another study from libertarian economists who know nothing about climate science. IOW, it’s comfort food for denialists and is uncoincidentally published in a disreputable “journal” that specializes in such things.

  89. Keith:

    OK. I give up. [edit] My typing may be poor but my qualifications to cal myself an synthetic organic chemist are considerable. 1st class degree in chemistry followed by a DPhil at Oxford, a post-doc at UPenn and several years in the industry (we don’t publish mate, too busy publishing patents!). I feel pretty comfortable with my abilities as do my coworkers.

    [edit - I have cleaned up some prior ad homs and in here. Leave it at home people]

    John Mashey and Ray Ladbury. Thanks. They are fair criticisms or my rationale. I would point out that planes and cars that are designed in a computer are subsequently tested in real life before being approved. So real experiments still matter. Proof is an interesting concept from a mathematical and philoshopical point of view. I think it’s important to distinguish between hypothesis, theory and so forth. You’re right that there is no such thing as absolute proof (although maths might be different!) but we need to try to get close. Models certainly do not constitute proof but they are on the way I agree. My beef is simply with the concept of being able to predict reliably what is going to happen in 50 years. I’m not scientifically convinced that the models are that great. Sorry, but that’s my view and perhaps using my own experience is not a fair comparison but it is what it is.

    Ray, about consensus views. It’s not science. Plain and simple. I’m sure that there are as many buzz topics in climate research that people follow and jump on the bandwagon as there are in my field. Man, chemistry is full of failed research areas that were the next big thing and didn’t live up to expectations. That’s a herd mentality and a consensus. Fair point to say the H pylori thing is an example of consensus working. It’s just that it was the second consensus that proved to be correct most of the time. That’s my point. We could go through several revisions of the consensus in climate change. I’m not directly criticising people who buy the consensus I just think we should recognise the dangers (and advantages) of it!)

    Deech56. Fair enough. I take your point. Ahh tagamet. Better than Zantac but marketed poorly. So they say. But all part of one big happy(?) family now. The models do do quite well, I just query whether they will fail over a longer period of data collection as my own models in my area have.

    I can see that many people here are fiercely protective of their models and views so I’m not going to post any more but I will continue to read since I have learned a great deal from many of the articles. I actually thought that was the point of the site; to educate and stimulate debate.

    I’m off to do some science.

  90. Peter Houlihan:

    Keith,

    Consensus in science can hardly be dismissed as a type of herd mentality. Rather it is what lifts a hypothesis to the level of theory.

    In biology we have a strong consensus that evolution explains both changes in the gene pool of a population and gives rise to new species. The consensus is not based on a vote taken by biologists, but rather by multiple lines of independent evidence (genetics, paleontology, developmental biology, etc.) all converging on the same basic mechanism. What converges is the thousands of independent research programs that work on the subject.

    Something similar has happened with regards to climate science.

    Your example of peptic ulcers is good example of consensus in science operating as it should. A consensus forms based on the best available information, and then a new set of data comes along that overturns the current paradigm. All science is provisional.

  91. John Nielsen-Gammon:

    #66 Keith – Accepting your analogies, now what? Clearly pharmaceutical companies have not decided that their models are worthless and stopped using them; they remain one piece of the puzzle despite their uncertainties. We also don’t conclude that because consensus views of certain diseases have turned out to be wrong, we may as well ignore all other consensus treatment protocols.

    Let me suggest an important distinction: in the case of molecular models for drugs, your hard-earned experience tells you that finding a drug molecule that does the trick is very hard. Say for argument’s sake that only 1 in 100,000 molecules will be useful, and the computer model is 99.99% accurate. Then 9 out of 10 molecules predicted as useful by this highly accurate model will actually be busts. Because a successful molecule is an extremely rare event, model failures will essentially be unidirectional and the model is untrustworthy by itself.

    Climate models, on the other hand, are constrained in important ways by energy balance and other physical processes. We know they’re reasonably accurate on a global scale for small, testable, perturbations to the current climate. There will undoubtedly be surprises in the future analogous to the ozone hole surprise in the early 1980s. (For the realclimate discussion of the chlorine peroxide issue, see here.) But the reference point is not an expectation of no climate change (the drug will fail unless proven otherwise) but an expectation of climate change consistent with both observed sensitivity and sensitivity from the simplest box models.

  92. Lawrence Brown:

    One of the factors that gives me confidence of the validity of the computer models is that when models are started from past conditions and are run to the present the models that don’t include anthropogenic actions don’t reproduce the observed climate past the middle of the 20th century, but the models that do include anthropogenic burning of fossil fuels do reproduce observed climate right thru the 20th century. (See Houghton, 3rd Editon, fig. 5.22.

    Not only do the models reproduce the observed climate, but the human element needs to be included to faithfully obtain this. Because climate scientists admittedly don’t understand evey detail related to climate doesn’t mean we should throw our hands in the air and declare them ineffective. On the contrary,there is a great deal of general agreement,from different climate models projecting a warming trend.

  93. Keith:

    Forgot one thing Barton. I an entitled to my anonymity. That is my choice. I haven’t published since my post-doc days due to the secretive nature of pharmaceutical research. However, I AM a peer reviewer for the American Chemical Society and the RSC. So I know how it works. And I’m quite sure that in the field of climate research there’s as much crappy work that gets published as gets published in my field (Elsevier journals anybody!). So don’t hide behind the peer-review crap. Science gets published so that it can be reviewed by the wider scientific community. It’s quality is only as good as the scientist and the reviewer. It shouldn’t work that way; reviewers could be better, but that’s the sad reality of it. So, open question. What journal in climate research is the best and which journals publish stuff that make you suck air through your teeth? To be fair, I’ll say that J Organic Chem is good for us and Tetrahedron Letters is dodgy. I have papers in both. ;)

  94. Julian Flood:

    quote Jeees, do you have any idea at all the magnitude of the forces involved that are powerful enough to have changed the Earth’s average surface temp by 1 degree F in 100 years???unquote

    Comment by Richard Ordway — 13 November 2007 @ 8:07 PM

    Oddly enough I have a rough idea. To offset AGW we need to produce 10^20 droplets per second of seawater at a micron size.

    The surface area of a 1-micron drop is 3.14 x 10-12 m2
    and the surface tension of sea water is 0.078 N/m so the very minimum energy is 2.45 x 10 -13 Joules per drop. This amounts to only 245 kW to cope with present world annual CO2 increases.
    So that’ll be 245 * whatever kW hrs.

    Next!

    (for those interested in cooling the planet, Google on Latham and Salter’s paper on using albedo increase.)

    JF
    Actually I just scrounged a section from Salter and Latham’s paper. Highly recommended.

  95. SecularAnimist:

    Timo Hämeranta wrote: “we have to wait at least to the 2010s to see whether the sceptics or the ‘mainstream’ scientists are right”.

    You omit a third possibility, which is that by the 2010s we will see that the so-called “alarmists” are right, and by then it will be much too late to avert a global catastrophe.

  96. SecularAnimist:

    Aaron Lewis wrote: “We are not going to have real action to combat or mitigate global warming until the full impact of AGW is communicated.”

    Which is exactly why the fossil fuel corporations spend millions of dollars paying the global warming deniers to endlessly repeat the falsehoods and distortions that are the subject of this thread: to simply make enough noise to drown out the science and ensure that the full impact of AGW is not communicated.

  97. SecularAnimist:

    Keith wrote: “I’d see the small scale earth experiment as being similar to an animal experiment [...] From my perspective, we simply aren’t allowed to put a drug anywhere near a human until it’s been in animals.”

    And yet, we are presently conducting a full-scale earth experiment, in which we are injecting a “drug” (CO2) into the entire Earth’s biosphere, where it is affecting the biosphere’s “metabolism”, and thus every ecosystem and every living thing on Earth, in ways that we have every reason to expect will be severely harmful.

    By the drug testing standard you mention, those who propose to build an energy economy based on burning fossil fuels should be required to perform whatever “small scale earth experiments” are required to prove that CO2 emissions are safe, before they are allowed to burn the first lump of coal or gallon of gasoline in the open air.

    Unfortunately it’s too late for that. It’s as though someone was talking about performing animal safety tests on a drug that has already been given to every human being on Earth.

  98. Dave Rado:

    Re. Sven, #30, in addition to the point CobblyWorlds made in #82, see also Tamino’s article Garbage is Forever.

  99. Dave Rado:

    Re. Ray, #32:

    I have never understood the seeming comfort that denialists take in trying to discredit the models, as if they were somehow discrediting the hypothesis of anthropogenic causation thereby. In reality, the case for anthropogenic causation does not depend in any way on the models.

    Yes, but see here. It’s partly the fault of climate scientists communicating badly to the public, in my opinion.

  100. Steve Bloom:

    Re #83 (TH): Over at Tamino’s Open Mind blog recently, there was a lengthy discussion on the solar stuff from leading solar physicist Leif Svalgard. He made numerous comments in two threads (here and here). Among other things, he has concluded that it is unlikely that solar irradiance varies enough to be a significant influence on climate. Period. Here he details the fatal errors of S+W (2007).

    Regarding Usoskin et al (2007), I’m not sure what Timo thinks he’s reading. The main result of this paper is to show that the long-term solar cycles are unpredictable. In terms of climate, the authors make no claim, and a quick glance shows why not: Yep, we’re in a grand maximum now, and there was indeed a grand minimum sort-of around the time of the mostly-nonexistent (globally) LIA, but going a little farther back we get l) pretty low activity at the time of the alleged MWP and, most fatally to your argument, 2) no correlation at all with the Holocene Thermal Maximum. IOW, the paper says the opposite of what you would like it to. Grasping at the last 150 years in the face of all that other evidence is a little pathetic, especially given the unquestionable discorrelation of the last few decades.

  101. Larry:

    NOVA show last nite stated 1/3 to 1/2 of American believed in creationism (and the earth is 4,000 years old?). Good luck explaining GW to them.

  102. Richard Ordway:

    Timo wrote: “So far, the following conclusion 12 years back is still valid:”

    Timo, in my opinion, your thoughts scare me and are in my opinion flawed. You seem to think that science is locked in a time warp like Star Trek. It isn’t. It moves forward…and in the case of global warming at warp speed.

    Your thinking is locked at a certain past event in time. However, the time is 2007.

    Since 12 years ago the science has only become more clear, has answered the critics with hard evidence and the opposing science has no evidence left.

    Since twelve years ago, the IPCC, and other national bodies have issued ever stonger statements as the science has advanced.

    Even some traditional deniers are throwing in the towel: such as many big oil companies in the face of overwhelming evidence…and in the face of an extremely hostile (to GW) seven year Republican Congressional majority and administration.
    http://www.msnbc.msn.com/id/18054970/

    As wikipedia states, “Dissenting statements:
    With the release of the revised statement by the American Association of Petroleum Geologists, no scientific bodies of national or international standing are known to reject the basic findings of human influence on recent climate.”…except perhaps you.

    This does not mean that GW is not being legitimately scrutinized…only recently (Nov. 2007) a study came out questioning that clouds might affect GW more than we had thought (ie, slow it down)-but remember, one study is going to have to overturn a body of evidence built up since 1824. http://www.agu.org/pubs/crossref/2007/2007GL029698.shtml

  103. Lawrence Brown:

    Re #97 Dave Rado says:”Yes, but see here. It’s partly the fault of climate scientists communicating badly to the public, in my opinion.”

    Then instead of listening to the climate scientists, let them listen to Pogo Possum- “We have met the enemy and he is us!” Seriously, the general public can comprehend a lot when motivated, and the motivation for action is becoming more evident with each passing season. I can’t believe that people are incapable of understanding that only the models that include human caused effects are capable of reproducing the observed climate of the last three or four decades.

  104. Phil. Felton:

    Re #95 rebuttal of Keith “Keith wrote: “I’d see the small scale earth experiment as being similar to an animal experiment […] From my perspective, we simply aren’t allowed to put a drug anywhere near a human until it’s been in animals.”

    And yet, we are presently conducting a full-scale earth experiment, in which we are injecting a “drug” (CO2) into the entire Earth’s biosphere, where it is affecting the biosphere’s “metabolism”, and thus every ecosystem and every living thing on Earth, in ways that we have every reason to expect will be severely harmful.”

    This was exactly the point I was going to make with the additional proviso that : the untested experiment is being carried out while warnings from the computer models suggest deleterious effects, the experiment continues and some of the predicted effects are observed, and still the experiment continues while further warnings emerge from the modelling!

  105. Imran Can:

    Gavin – I completely agree that the purpose of the pT predictions is about long term trends (ie. 2100). And itsa shame the informations about the standard deviation isn’t stated on the graph (see page 34):
    http://www.ipcc.ch/pub/un/syreng/spm.pdf

    What is stated is “the grey region shows the range of results from the full range of the 35 SRES scenarios ….”

    Even my 8 year old daughter can plot the last 10 years on this graph and see that they fall below this range (below the grey area). So for the general public (who have access to this report) all they can see is that the scenarios all overestimated the problem – at least up to 2008. They don’t see ‘standard deviations’ – they don’t see the words that say ‘ignore the short term, – just look at the 2100 figures’. Can’t you see what the credibility problem is here ?

    And my remark about respected scientists is on people like John Christy – see recent news article ..
    http://news.bbc.co.uk/2/hi/science/nature/7081331.stm

    Now when you combine all these elements, is it any wonder the general public just isn’t that worried …. ??

    [Response: a) the public are plenty worried, b) I'm very impressed at your eight year old, since she would need to squeeze the eight data points into less than a square millimeter on the graph on p34 and her ability to detect a significant difference would require a scanning electron microscope. The fact is that trends of ~0.2 deg C/decade were predicted even as far back as 1988, and have indeed come to pass - your 8 year old's drafting skill notwithstanding. - gavin]

  106. Ray Ladbury:

    Keith, You are not talking about scientific consensus. Scientific consensus deals with the question of how strong a statement one can make without outrunning the evidence. It is always conservative. Example: there is consensus that climate sensitivity is between ~2.2 and 4.5 degrees per doubling of CO2. That is supported by multiple lines of evidence and so is hard to dispute. There is no consensus about how climate change will affect hurricanes, even though there is evidence that suggests some increase in severity and many in the community believe this is a logical outcome. It is known that the IPCC forecasts of ice melting are too conservative, but no consensus can be reached yet as to how they should be corrected. This is not a case of a bunch of guys getting together over beers and saying, “So, what do you think?” Consensus is essential to the scientific method, because it is the only way to dilute subjective personal opinion. The way to measure scientific consensus is not to take a poll, but rather to look at what scientists are publishing–and alternatives to anthropogenic causation are nowhere to be found in peer reviewed journals. Another way to measure scientific consensus is to look at position statements by the national academies and by professional societies. With the new statement issued by the American Association of Petroleum Geologists, there is now not a single professional or scientific society that dissents from the consensus that humans are changing climate–I will say that one again: Petroleum Geologists!!! Don’t you think that the evidence would have to be overwhelming to cause them to back down?
    I have noted this before, but in 18th century London, the ghost of Newton was so strong that it kept English scientists flailing away at Newton’s failed corpuscular theory of light while their counterparts on the Continent followed Huygens and his wave theory. The result was that optics in England lagged decades behind optics on the continent. In the mid 20th century, the most famous and influential scientist of the day, Einstein, bitterly opposed the indeterminacy of quantum mechanics. Yet physics marched around him and ultimately over him. The difference: by the mid 19th century, the importance of scientific consensus had been realized.
    When anti-science types want to attack science, consensus is where they attack. This is true on the right (climate denialists and creationists) or on the left (Paul Feyerabend and his scientific anarchists). Consensus is one of the keys to why science works, because at its core is the agreement by scientists to judge based on the evidence and not on their personal interest or preference.

  107. Pat Cassen:

    We should all heed carefully Timo’s post #9. It is as clear and articulate an expression of a faith-based position as one can find, a position at the heart of many a sceptic’s view. As such, it is immune to scientific (evidence-based) argument, and is probably assailable only by the impact of contradictory circumstances experienced at a very personal level, such as those presently encountered by Arctic dwellers (or perhaps by falling in love with someone of the opposite view).

    I would no sooner argue against Timo’s faith than I would argue against his or her religion. Nevertheless, we are obligated to explain, in as straightforward and dispassionate manner as possible, the scientific basis of AGW, and why we believe that the scientific conclusions demand mitigating policy. And we should certainly continue to correct the abundant misrepresentations of the science, both faith-based and fraudulent. There are still plenty of folks out there, many in positions of authority, who value scholarly endeavor and respect the basic integrity of the scientific process, despite all its weaknesses.

  108. Ray Ladbury:

    Imran Can, Maybe you shouldn’t rely on 8 year olds for you scientific understanding?

  109. EricM:

    RE: 82

    Using your peer reviewed reference with a different (longer) time scale clearly shows the cyclical nature of temperature versus time, and picking any of the eight plots except one, clearly show past temperature peaks higher than today. http://www.globalwarmingart.com/wiki/Image:Holocene_Temperature_Variations_Rev_png

    I was not defending the particular chart used, which I agree is highly unscientific. The point I was attempting to make is that it is very difficult for highly educated, technically sophisticated experts, many of whom post here, to convince a goodly portion of the population that there is a problem, let alone a crisis, when all a contrarian has to do is pull out a simple long term temperature chart showing the earth has “survived” numerous warm cycles in the past.

    [Response: Please read the excellent text that goes along with that picture and think about how robust that graph actually is. Now think about where an extra 3 degrees or so of global warming by 2100 (under BAU) will put us relative to this previous 'warm cycle'. Still complacent? - gavin]

  110. Ellis:

    Here, Here to more substance. I, for one, would appreciate more on the science of AGW and less on the apparent stupidity of skeptics. I am pretty sure that the requirements for respectable scientists include abidance to logical infrences and skeptisism toward any result until such result has been verified by independent sources. As to consensus, this is a fallacy of logic, argumentum ad populum, and as Wiki says for fallacy, “A fallacy is a component of an argument that is demonstrably flawed in its logic or form, thus rendering the argument invalid in whole.” As for verifiable results, the lack of data archiving in the climate science field is astonishing and continues, for me, to be one serious stumbling block in accepting theory as fact. For any science to move foreward there needs to be transparency with data and results, especially for those trying to audit the work. It seems obvious to me that if a scientist is willing to publish papers on any subject that they are confident in their results and should want others to try to disprove any part of their hypothesis. The failure to disprove only adds to the robustness of the results.
    Which brings me to the failure of skeptics to disprove AGW. The theory of AGW rests only on one principle, as far as I can tell, that the warmth of the past century is outside the bounds of natural variability. Natural variability is the only axiom that any skeptic needs. AGW is a theory, and as such needs to prove departure from the axiom of natural variability. Thus, the burden of proof is on the scientists of AGW to provide facts in support of their conclusions, and not on the skeptic.

    [Response: This is a fallacy. Given that Snowball Earth and the Cretaceous hothouse clearly delineate the bounds of natural variability, your argument is equivalent to saying that nothing less dramatic than the freezing over of the oceans or the raising of the temperature by 10 deg C or so can possibly be attributed to any forcing. This is absurd. The issue is not whether any climate change was bigger or smaller than today's - it is whether it can be explained, and whether that explanation has validity today. So while orbital forcings, giant volcanoes, asteroids, Heinrich events etc. have all caused dramatic climate changes in the past, none of them are relevant to today. Just because large forest fires have occurred naturally in the past, does that imply that arson cannot happen? Or that if we see someone walking away from a fire with an empty kerosene can and some matches, we can't logically infer that he may have had something to do with it? - gavin]

    As far as the proof now presented for the departure from natural variability, we have temperature reconstructions and CO2 levels presented through ice cores. If we look at the spaghetti graph of IPCC 4 we find that the proxy data, not the observed temperatures that is superimposed over the proxies, remains within the structure of natural variability, with the understanding that most of the proxy data has not been updated to 2006. Perhaps, the updates would show the depature, maybe they would not, either way there is really no way to know until someone actually goes out and get their hands dirty, and publish the results, and archives the data. As to the ice core record of CO2 levels in the past I am very dubious, especially the wont of people to compare atmospheric levels to the ice below the firn. Ice dynamics, as is everything related to climate science, is a tricky thing to be sure of, and I for one will feel alot more comfortable in the proclimation of anomylous CO2 readings in the past hundred years once we can compare the results of Mauna Loa, since around 1960 with ice cores beneath the firn. I believe that information will be available within about 20 years from now and is much anticipated.

    As a postscript, I would like to add that in looking around for scientists that did not abide by logic and verifiable results I instantly thought of the cold fusion debacle of the late 80′s. I was ready to brand, Fleishman and Pons as scientists who commited fraud in their actions and deeds, only to stumble upon
    http://www.wired.com/wired/archive/6.11/coldfusion.html?pg=1&topic=&topic_set=
    You would think upon reading the article that this would be an area of great intrest, especially now, with the search for alternative fuel. But, alas this work falls outside of the consensus and has very few avenues for funding and for publication.

    [Response: Indeed.... - gavin]

  111. James Linder:

    The peptic ulcer scenario is interesting. Consensus was amongst doctors who believed ‘The Explanation’ even though it was wrong, not amongst scientists who believed by informed thought, test, models and theory.
    Also when Mss Barry J. Marshall and J. Robin Warren made their discovery they were not proclaimed heros, it took years to be accepted. Methinks that if AGW was found to have a fatal flaw then Gavin et al and most readers here would be at the front of the queue saying ‘Houston we have a problem …’

  112. Ray Ladbury:

    EricM, you seem to have thought this about halfway through. According to any “periodicity” in the plots, we ought to be cooling. Instead, we are warming–SHARPLY! This suggests that we are moving outside of the conditions under which all of human civilization evolved.

  113. Dave Rado:

    Re. #103,Lawrence Brown, you misunderstood my point. I was not suggesting that “people are incapable of understanding that only the models that include human caused effects are capable of reproducing the observed climate of the last three or four decades.” I was commenting on the Ray’s and Gavin’s point that many laymen think erroneously that the only strong evidence for AGW is the models and that if the models were to turnout to be unreliable the whole theory would collapse. They blamed this misconception on the so-called “sceptics”. I blame it at least partly on the fact that many climate scientists on TV and radio programmes, when asked how we know for sure that current warming is “man-made”, reply: “because the models do not match the observed data unless human-emitted CO2 is taken into account.” IOW they erroneously imply to the uneducated that that is the only strong evidence that we have.

  114. Steve Reynolds:

    Does anyone here think most of this is money well spent (chiefly on ethanol)?

    “Between now and 2012, biofuel subsidies will total more than $92 billion, according to a recent report conducted under the auspices of the Global Subsidiaries Initiative.”

    http://www.news.com/8301-10784_3-9816534-7.html?tag=head

  115. Richard Ordway:

    re “And my remark about respected scientists is on people like John Christy” -

    Errr, John Christy is respected? He has some questionable conflicts of interest and a history of ignoring published data in his findings:

    http://www.exxonsecrets.org/html/personfactsheet.php?id=903

    Please do a realclimate.org site search on John Christy and a Google search.

    The IPCC has Christy, in part, to include all, ahem, viewpoints…to the IPCCs credit.

  116. Steve Bloom:

    Re #109 and reply: Just to add that EricM might want to also consider the state of the planet the last time things were that warm. The next graph doesn’t quite get us to +3C, although it does get us firmly out of the Pleistocene, all the way through the Pliocene and to the end of the Miocene. That should do for all of the ice outside the East Antarctic ice sheet (=> about 14 meters of sea level rise among other symptoms), and probably a bit of the EAIS as well, so call it 20 meters total.

    Going to the next graph, we can finally locate our +3C spot about 12 million years ago in the mid-Miocene. Notice anything happening just then? If we actually stabilize at that level, probably some of the EAIS will remain. It’s really hard to know exactly how much, so let’s split the difference and figure that our +3C gets us 50 meters (= about 160 feet) total sea level rise. Just a little warmer and that EAIS remnant goes, bringing us up to the grand total of 80 meters or so (= about 260 feet). Have a look at these maps for the consequences.

    Unlikely-sounding, you say? Well, bear in mind that the Pleistocene has been an almost uniquely cold era in the Phanerozoic (the era of complex life that started about 550 milion years ago, shown in this final graph), and that the planet has been free of significant permanent ice for something like than 80% of that period. I mention this last point not because it proves anything directly, but to observe that it’s unlikely that there’s some factor we don’t know about that will do us the favor of keeping the planet cold.

    Finally, I think it would be helpful for you (and anyone else who hasn’t) to read this article by Jim Hansen, who goes into the short-term risks and outlines some of the steps we need to take to avoid the worst of it.

    (PS — Many thanks again to Robert Rohde for producing these lovely and useful graphics.)

  117. EricM:

    RE: reply to 109, 112, and 116

    From the (agreed) excellent text that goes with the picture:
    …it should also be noted that the 2004 measurement is from a single year (see Image:Short Instrumental Temperature Record.png for comparison to other years). It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times but are unresolved by the resolution available in this figure. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot.

    Not complacent, no. Just not willing to call the current situation a crisis, nor willing to believe the earth is so fragile that it will be permanently “damaged” by the current rise in antropogenic GHG’s, thereby warranting immediate and drastic changes in lifestyle.

    I fully support efforts to continue the AGW research, and I fully support (and advocate for) taking realistic steps to reduce our carbon footprint and develop alternative energy sources. My biggest pet peeve with most advocates of global warming crisis theory is that any “acceptable” solution has to meet thier pre-concieved green agenda, and they refuse to consider viable existing solutions using current technology. If AGW is so potentially catastrophic, why aren’t we building nuclear and hydroelectric plants just as fast as we can? We could cut our carbon footprint by 40% in 10 years!
    However, I also support the right of countries like China and India to fully develop and use thier carbon based energy reserves to increase the standard of living of thier people. With a higher standard of living comes better health, better education, greater environmental awareness, and more political stability. I see those as very tangible global benefits that must be entered into the global equation as offsets to the negatives of AGW. Who knows, maybe the man who will finally develop the clean energy source that will replace fossil fuels once and for all is a peasant boy in central China who is just now getting electricity from the new coal fired power plant down the valley.

  118. Lawrence Coleman:

    I’ve been spurred to write again after seeing an article about this years summer artic ice melt. It’s grown by 23% sinve 2005. Now ther’s only just over 4 mil sq kms of permanent ice and that’s getting weaker and more fragile by the day. I recommend this site be devoted to discussion on how to mitigate this imminent catastophe rather than bicker over the different fetaures of the deckchairs on this titanic.

  119. Mike Donald:

    Just 10 contrarian debunks from the beeb? The skepticalscience link has a list of 47 contrarian debunks of them and pretty well explained IMHO.

    BTW realclimate’s excellent compendium pairs “John Cross” with Skeptical Science.

    http://www.realclimate.org/index.php/archives/2007/05/start-here/

    Minor typo I think. Should be John Cook?

    http://www.skepticalscience.com/argument.php

    #105 #115
    That Christy chappie. Wasn’t he in TGGWS? Hardly something he’ll put in his CV I daresay.

  120. John Mashey:

    #89 Keith

    The point of my comments was:
    1) One can be an expert in a domain that uses modeling.
    2) One can have a very accurate opinion about the usefulness or lack thereof of modeling in that domain.

    3) But no matter how expert in one domain, over-generalizing to others is very dangerous. I really don’t understand repeatedly asserting the non-working of climate modeling by someone who doesn’t have relevant experience, and I’m sorry, but biochemical modeling isn’t the same, just like I said.

    4) “I would point out that planes and cars that are designed in a computer are subsequently tested in real life before being approved.”

    I’m sorry, that sounds good, but I suspect you haven’t worked closely with the people who do this, have you … and yet, you are *sure*. I don’t think anyone has been challenging your biochem expertise [I certainly haven't], but you keep denying the expertise of people who are as expert in their domains are you are in yours. Why?

    As a matter of ACTUAL FACT, car companies routinely do crash simulations of numerous cases that they *never, ever* try in real life. Of course they all do some real tests, but they do far more simulations than real crash tests, and they make design changes based on the results, because the simulations have proven good enough. [And cars are *way* safer, by the way. Oddly, sometimes removing metal makes a car safer in some crashes.] Look up: virtual crash test dummy.

    They do all this in order to improve performance or reduce weight, which means retaining safety, but lessening over-engineering. Likewise, airplane companies simulate all sorts of things that they never test in real life.

    [This isn't theoretical or something I read somewhere. At one point, almost every car company used computers I helped design to run crash codes, and I used to visit them regularly, as well as Boeing, and actually, a majority of the big pharmas, talking to people who did molecular modeling, so I had some idea of the differences in difficulty.]

    *PLEASE* go read that Kaufmann&Smarr book.

  121. Rikard:

    Gavin, you claim that “…In merging the two records Ahluwalia multiplied one record by a factor to get a similar amplitude change but only over the period of overlap prior to renormalising. This makes absolutely no sense and all the trend is due only to that procedure.”

    Ahluwalia justifies his multiplication with a conclusion that there must be something wrong with the measurements from Yakutsk in solar cycle 19, as the data fit for cycle 20. If so, it seems more reasonable to truncate the series and not use the faulty data. But even if he would have done that he would still get trends in the data, but with less certainty (as the matching overlap would be reduced to some ten years. And if the Yakutsk series is taken at face value the GCR crew can still claim a strong correlation to recent cooling and warming. Don´t we have better arguments against the GCR-climate link?

    You further reply “… Finally, there is no evidence that the interstellar GCR spectrum has any energy dependent decadal variations….”. Shall I understand that as that we have evidence that the GCR spectrum does not have energy dependent decadal variations (in which case it is a nice torpedo against the hypothesis that GCRs are being responsible for recent warming) or do you mean only what you say (in which case it is reduced to an open question)?

    [Response: Two points, and now i'm starting to repeat myself so this will be the last time: No individual record shows any trend. Yakutsk does not show a trend. Cheltenham does not show a trend, Climax does not show a trend, etc. Taking systematic offsets and amplitude variations between them and creating a 'trend' is not a valid procedure. As to whether the interstellar background GCR has decadal variability that is independent in only the energies that we have no knowledge of and that fit a post hoc idea of what might affect clouds is special pleading on a galactic scale. I'm not an astrophysicist and so my knowledge of GCR sources is small, but as I understand they must emerge from very high energy events like supernova remnants and the like. That doesn't allow much room for increases in one kind without increases in others. - gavin]

  122. CobblyWorlds:

    #117, EricM.

    I agree, we’re not yet at a crisis point, but as we’re not at equilibrium with the temperature increase to be expected from our emissions so far. And the faster we emit, the longer we continue to emit, the longer we will have to reach equilibrium and the greater our warming commitment will be. For us to consider ourselves in control of the process we must bear in mind we’re operating with a latency between our reaction and the results of our actions.

    Yes the Earth will survive. But the Earth (biosphere) has survived the Permian Triassic extinction and the KT extinction – the Earth may survive such events, but they would be terrible for our species/civilisation. From my reading it seems to me that our best analogue for what we’re doing now is the Permian Triassic event, except we currently seem to be proceeding along that path much faster than when that event happened (i.e. the initial CO2 release from Vulcanism – that we’re now doing with our emissions).

    As our emissions have had such an impact on the carbon cycle that it’ll take hundreds of years to substantially reduce the CO2 in the atmosphere/ocean following a cessation of emissions (Archer). By the time we get to around 6degC global warming, (ocean thermal inertia allowing) we may be committed to continental shelf methane clathrate outgassing – which would cause a substantial further hike in temperature. We have only used less than 10% of the available fossil fuel reserves (mainly coal), in doing so we have caused an observed warming of around 0.8degC with a further ongoing warming commitment on topm of that.

    I agree that all people have the right to develop, we in the “developed” world are simply leading the way. Once I learnt enough of this science to form an opinion I realised my former scepticism was wrong, and that my former “Thatcherite with Fukyama sympathies” position was not sustainable in the face of evidence.

    These figures are a bit dated, but:
    UK emissions and per-capita.
    http://cdiac.esd.ornl.gov/trends/emis/uki.htm
    US emissions and per-capita.
    http://cdiac.esd.ornl.gov/trends/emis/usa.htm
    China emissions and per-capita.
    http://cdiac.esd.ornl.gov/trends/emis/prc.htm
    India emissions and per-capita.
    http://cdiac.esd.ornl.gov/trends/emis/ind.htm

    The US per capita emissions are about 5 tons Carbon per person. But lets leave that aside and look at the UK, which is only 3 tons C per person. I’m British and I have a good standard of living on only a modest wage.

    India (~1.2bn people) is rising towards 0.3 tons Carbon per person.
    China (~1.3bn people) is rising rapidly over 1 ton Carbon per person.
    So even if they only aim for 3 tons per person as opposed to 5 tons, it still implies a massive increase in overall emissions. Note that the UK seems to have got it’s emissions under control after the 1950s – before taking comfort in that, note also that we’ve “exported” much of our manufacturing base, which was once substantial. Note also that much of China and India’s emissions increase is due to industry – they still have a substantial body of the poor that can only aspire to emitting close to the national “per capita” figures.

    We can agree in principle that all have the right to the empowerment and personal health and comfort afforded by modern technology liberated by the free-market. But in face of the figures the path we are following as a species is not sustainable. I have no solution to that problem, I consider it insoluble. But I cannot ignore hard evidence to suit what I may wish for.

  123. Barton Paul Levenson:

    Keith writes:

    [[What journal in climate research is the best ]]

    It doesn’t work that way. They concentrate on different things. If you want a sample of the top climatology journals, try the Journal of Geophysical Research — Atmospheres, the Journal of the Atmospheric Sciences, and the Monthly Weather Review (which, despite the title, publishes a lot on climatology).

    [edit]

  124. TonyN:

    Gavin: Are you going to post on the Christy article also in the BBC pages on sceptics?

  125. Timo Hämeranta:

    About Arctic sea ice please see:

    Morison, James, John Wahr, Ron Kwok, and Cecilia Peralta-Ferriz, 2007. Recent trends in Arctic Ocean mass distribution revealed by GRACE. Geophys. Res. Lett., 34, L07602, doi:10.1029/2006GL029016, April 4, 2007

    “…The spatial distribution and magnitude of these trends suggest the Arctic Ocean is reverting from the cyclonic state characterizing the 1990s to the anticyclonic state that was prevalent prior to the 1990s. ”

    Nasa news November 13, 2007

    “The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.”

  126. Timo Hämeranta:

    Layman participants and readers of this blog have surely identified the Current State of Climatology:

    “The research found that the climate change discourse in the UK today looks confusing, contradictory and
    chaotic. For every argument or perspective, whether on the scale of the problem, its nature, seriousness,
    causation or reversibility, there is a voice declaring its opposite. The conclusion must be that the battle is
    not won: climate change is not yet an issue that is taken for granted. It seems likely that the overarching
    message for the lay public is that in fact, nobody really knows.”

    Ref: Ereaut, Gil, and Nat Segnit, 2006. Warm Words: How are we telling the climate story and can we tell it better? Institute for Public Policy Research (IPPR) publication, August 3, 2006

    False confidence we see all the time, but scientifically speaking uncertainty is the only sure thing.

    For 30 yrs policymakers are recommended to reduce GHG emissions, more precisely the developed countries should reduce their emissions in order the developing countries could rise their standard of living without reductions.

    The recent IEA World Energy Outlook 2007 has ruined this plan, if global reductions should be carried out.

    When I concentrate in the CO2 in the atmosphere, I have wondered how obsolete all these suggestions are.

    Whether or not CO2 emissions are dangerous in future please think again:

    Is it really necessary to leave unused the fossil energy?

    Is there really no other solutions(s)?

    Well, 30 years ago no, nowadays yes.

    And I’m not thinking geoengineering the atmosphere or pumping CO2 into boreholes.

    Human ingenuity has already solved this problem.

    With interest I follow when the newest innovations gain the publicity and support they truly deserve.

    Our Future is Bright.

    This is my final contribution to this blog.

  127. pete best:

    Re #118, dont you mean its shrunk by 23% ?

    re #116, is the 2C threshhold 400 or 450 ppmv and is James Hansen telling us that 1 more degree from year 2000 levels (0.8 C) which means around 1.8 C come 2040 at 0.2 c per decade all that we can realisitically hope for ?

    It is going to take until 2040/2050 to have mitigated CO2 by 80% globally whatever solution(s) we use. This would mitigate 3C but not 2C. The other worrying thing is the sheer rate of CO2 accumulation in the atmosphere. Regardless of what has gone on before in previous ages and epochs noting compares to the rate of change being experienced today. This may prove to be a significant factor.

  128. Imran:

    #105, 108
    Guys – thanks for the comments :) … indeed it does require a slight ‘zoom’ for an 8 year old to be able to plot the points …. but it can be done and the fact that its done by an 8 year old doesn’t detract from the observation … the points fall below the range shown in the report. Which is a credibility problem for the IPCC.

    But I do agree that over the last decades the temperature has gone up – although when I was doing some basic geometry calculations with my 12 year old daughter on the STEEPEST part of the slope during the last century (which was 1975-2005 if you want to double check) we could only get the data to support a 0.18 deg/decade. I guess its ok to round it off to 0.2 and call it a trend.

    http://www.globalwarmingart.com/wiki/Image:Instrumental_Temperature_Record_png

  129. catman306:

    Stossel (20/20) serves up the contrarian message
    http://onlineathens.com/stories/111507/opinion_20071115003.shtml

  130. GlenFergus:

    #105

    I’m rather older than 8, but I can draw graphs.

    Here’s the TAR SPM Fig 10b with HadCRUT3v through June 2007 plotted. I’ve zoomed in and shifted the temperature axis across for clarity. If anything, the IPCC 2001 predictions are looking a touch low, if anything…

    [Response: Note that the zero line on that graph is '1990' - to avoid adding too much noise, I'd calculate the anomalies from the 1985-1995 mean (which is not the raw numbers in the HADCRU data). Regardless - I doubt that anyone will have drawn conclusions from such a exercise - 8 years old or not. - gavin]

  131. TonyN:

    Timo #126

    Here’s another couple of quotes from the IPPR’s ‘Warm Words’.

    To help address the chaotic nature of the climate change discourse in the UK today, interested agencies now need to treat the argument as having been won, at least for popular communications. This means simply behaving as if climate change exists and is real, and that individual actions are effective. The ‘facts’ need to be treated as being so taken-for-granted that they need not be spoken.
    The disparity of scale between the enormity of climate change and small individual actions should be dealt with by actually harnessing this disparity. Myth (which can reconcile seemingly irreconcilable cultural truths) can be used to inject the discourse with the energy it currently lacks.

    This is great advice for UK politicians who really want to change the public’s attitude to climate change and they seem to be doing just what the IPPR suggest.

  132. Keith:

    John. I hoped not to get pulled back into this but….

    I think you have misunderstood my point. I agree that it is not directly possible to transfer my knowledge of chemical and biochemical models to climate models. Directly. I’m not that stupid. However, cross fertilisation of ideas between disciplines is possible and desirable. I, personally, have found it immensely stimulating to try to get to grips with many of the topics discussed on this forum. All I was trying to do was suggest that the problems that we face in the med chem world may have some relevance in yours. It is always good to question your hypothesis. Which is what you are saying climate modellers do and I’m questioning whether that is being done sufficiently. That’s it. I am not disputing the current warming observations. I am not a denier. I am skeptical and have some legitimate questions. So far I have been met with a wall of “no our models are great. They predict really well”. Not one person has said “That’s an interesting observation, Keith. Let me think. Yes, an experiment is a idea but here are the problems and this is why the models are OK at this stage but yeah you make a fair point etc…..” It is a totally polar debate. There are many people, like myself, who have scientific expertise but who have doubts and queries and to be honest being ranted at doesn’t make me sympathetic to your views. It’s as bad as listening to outright deniers in fact.

    As for your car model discussion. I didn’t suggest that models weren’t used. One of my old buddies from my PhD days works (she’s a phys chemist) for Jaguar on this very thing, so I do have more than a passing knowledge but nowhere near that of yourself. They very rarely have to redesign a crash structure that worked in the computer but didn’t in an actual crash test. Relative to climate it’s a simple model and the training dataset is large and varied. So,a great model. But they STILL go and do the actual crash at the end. Just to be sure. So there we have an example of a model that works almost perfectly. We have models in pharma that don’t. So where is the experiemntal work to show where the climate model is? And that is my point, even if it seems to be unresolvable becasue the experiment can’t be done. That is why I am a little skeptical on the output of the models. But look on the bright side, I’m very close to being a believer. Just one experiment!

    I read the Kaufmann book during my DPhil. Hard going for me but interesting. My skills are tuned to taking a problem and working backwards to best figure out how to solve it from the start. We take the end result and figure out how we got there and then go do it. It seemed to me that the book (and modelling) was about the reverse (certainly in terms my sense of what that means, but retrosynthesis is something a lot of people just can’t get their head around) so it was tough going but valuable.

    It is shocking, however, that a field that should involve a number of disciplines seems to be so defensive / aggressive and so closed to the thoughts of others with different experiences outside that domain. Depressing all round really.

  133. TonyN:

    Re #131

    The trouble is that scepticism is part of UK culture and it will be very difficult to dispel. In fact a recent MORI poll showed that only about 20% are totally convinced that anthropogenic climate change is happening. And it gets worse. There are people over here who mis-interpret what the IPPR are advising in the quotes above (#131). They think that what ‘Warm Words’ really tells the politicians is, ‘Don’t mention your doubts in front of the children, just keep on feeding them faerie tales’. They even question why the authors feel that it is necessary to put ‘facts’ in quotation marks.

  134. Hank Roberts:

    Tony, you’re looking at “political science” — public policy research — from IPRR.
    Quotes like those make people think political science is an oxymoron.

  135. Lawrence Brown:

    Re #113- Point taken. The general needs to know that the temperature record and proxies such as tree rings, ice cores,boreholes, and coral reefs are corroborating indicators of change, as well. The temperature record,itself, shows a steep rise in the last few decades of the 20th century.

  136. Chip Knappenberger:

    Re: Comment 81:

    Tamino,

    Interesting analysis. I would have supposed that a 16th order polynomial would have been over fit… I suppose the BBC reporter Richard Black could have used a 16th order polynomial as the basis for his statement, but I imagine that Gavin probably would have talked him out of it, as I would have hoped Gavin would have talked him out of comparing the 1979-2006 rise with the 1900-2006 rise since the post-1979 rise was more or less linear while the post-1900 rise was more complex and thus the comparison is out of context. One could just as well argue that the 1900-1945 rise accounted for more than half of the overall rise, but that would seem to produce a paradox…

    -Chip

  137. Charles Muller:

    Concerning recent trends for global surface temperature, it’s hard to say there’s a huge warming. The question is not to compare with 1998, but to observe a stagnation in the past six or seven years. There may be many causes for that – for example natural variability, CH4 atmospheric stagnation since 2000, end of global brightening, etc. So, it’s not presently a real challenge for AGW theory (or for a strong component of anthropogeneic forcing in recent trend).

    But for sure, if surface temperatures were to stay as quiet as they are since 2001 for a decade or more, I guess this would require an explanation, because human forcings are growing each year, and with an increasing rate according to IPCC 2007. Knight et al. 2007 recently suggest (in Science) from a better-tuned short-term predictive model that half of the years after 2009 will be warmer than 1998 : we’ll see.

    Thereafter, Hadley Center data (I took them because there’re more congruent with UAH and RSS low troposphere trends, and with WMO annual statement, than Nasa Giss).

    Hadley data / Anomaly vs 1961-90
    2001 : 0.406
    2002 : 0.455
    2003 : 0.465
    2004 : 0.444
    2005 : 0.475
    2006 : 0.423
    2007 : 0,430 (9 months)

  138. Chuck Booth:

    Re # 76 Ray’s response to Keith (# 11) ” There was little evidence to begin with establishing causation by H. Pylori. It took time to accumulate the evidence, so it took time to change the consensus.”

    Not only was there little evidence the bacteria might cause ulcers, there was very good reason to think they couldn’t possibly be the cause had anyone considered it: The high acidity (pH

  139. pete best:

    http://environment.newscientist.com/article/dn12925-china-on-target-to-meet-renewable-energy-goal.html

    renewables increase significant but so does fossil fuel use due to increasing energy demand levels.

  140. dean_1230:

    Re #130

    One problem with the linked plot is that you’re extrapolating at the same rate that’s been experienced over the last 30 years. One thing this graph clearly shows is that such an extrapolation is clearly a risky thing to do. If the graph was truncated at the year 1940 and the same method was applied, then the resulting temperature rise would be well over 1°C. It’s not that it couldn’t happen as has been hypothesized, but that there’s evidence in the recent past of it NOT happening as proposed.

    Likewise, concerning the recent (100 yr) temperature data (using the HadCRUT3 plot earlier referenced), what was the forcing function for the time period 1910-1940? It is my understanding that the cooling of the 40s and 50s was due to volcanic activity, but what was the earlier temperature rise due to? It’s not, from what i understand, due to CO2 (at least the magnitude of temperature rise vis-a-vis the increase in CO2 levels doesn’t match current understanding).

    This plot also shows that the claim that the temperature is rising “faster than ever before” isn’t exactly accurate. From 1910 through 1941, the global temperature rose from approximately -.55°C to 0.03°C (0.58°C) or 0.0187°C/year. From 1976 to 2006, the temperature rose from -0.14°C to 0.45°C (0.59°C) or 0.0197°C/year. Ok, so it is slightly higher, but it is well within that which has been seen before and which is NOT being attributable to CO2 increases.

  141. David B. Benson:

    Keith (132) — Have you explored the Start Here link at the top of the page? Have you read the AIP Discovery of Global Warming linked in the Science section of the sidebar?

    These ought to get you started understanding the actual experiments and observations which are then encorprated in modern general circulation models.

    Also, a paper by Abe-Ouchi/Segawa/Saito describes modeling the entire last ice age from the Eem to the Holocene. Quite a severe test, I should think.

  142. Marcus:

    Keith: Part of the reason why people are reacting poorly is that you keep setting up strawmen and repeating the favorite arguments that denialists always use.

    For example, your first post claimed that consensus is “poor science” when in fact, science is built on consensus. Otherwise, every scientist would have to redo every single fundamental experiment done in the past century before they could move on to do even a simple new experiment. Occasionally the consensus is substantially wrong – but that is a rare event. Ulcers and plate tectonics are the two examples that everyone brings up as examples of consensus totally missing the boat. More often, the consensus just needs to be modified around the edges – eg, newtonian mechanics being modified by relativity. If you are an expert in a field, then you always keep an eye out for anomalous results, because proving the consensus wrong is an instant ticket to fame. But for fields where you are _not_ an expert, then it would be extreme hubris to assume that your intuition is superior to the consensus of experts in the field.

    To move on to your other point about models, there are multiple strawmen you pose: first, that AGW theory depends solely on models. This is in no way true – there is plenty of non-computational evidence, including predictions made in the 19th century. Second, that modelers assume their models are perfect: this requires ignoring the wide range of uncertainty demonstrating in every plot of model ensemble runs. And most modelers recognize that in addition to parameterizations that we can bound, there may exist surprises and feedbacks that we either do not have sufficient knowledge to model (eg, ice shelf collapse) or may not even know exist yet. However, these unknowns are as likely to be negative as positive, which the denialists who bring up uncertainty always forget to mention. Third, you claim that models are always tested by experiment: I will point out that no one will ever test an airplane that 9 out of 10 models claim will crash. In your own sphere, I will point out that the Mayo group at Caltech does a fair job at solving the reverse protein-folding problem computationally. And just as there are rare examples where consensus has been proved wrong, I will also point out that there are (also rare) examples where models or theory have proved more reliable than experimental data: the ozone hole is one, Marcus Theory for photosynthesis is another, and corrections to satellite temperature data is a third. Fourth, and finally, you claim that there are “no experiments” for our models, but there are a number of “natural experiments” which have been used, Pinatubo being the most well known example, but models are continually tested against historical datasets.

  143. Chuck Booth:

    Got it: I was using an illegal symbol!

    Re # 76 Ray’s response to Keith (# 11) ” There was little evidence to begin with establishing causation by H. Pylori. It took time to accumulate the evidence, so it took time to change the consensus.”

    Not only was there little evidence the bacteria might cause ulcers, there was very good reason to think they couldn’t possibly be the cause had anyone considered it: The high acidity (pH 1-3) of the stomach contents and the near absence of viable bacteria in the stomach contents pretty much ruled out any likely role of bacteria (of course, some bacteria do survive the trip through the stomach – that is how we get food poisoning). It wasn’t until Robin Warren and Barry Marshall started looking at stomach lining biopsy samples (old published results and new samples) that they found H. pylori living in contact with the stomach lining (epithelium) under a protective layer of mucous (Warren, J.R. 1984 Lancet, June 4; Marshall B. 1984, Lancet, June 4). And the presence of H. pylori was correlated with the occurence of gastric ulcers. As it turns out, only an estimated 80% of gastric (peptic) ulcers are directly attributed to H. pylori, and excess stomach acid is considered the cause of some gastric ulcers (along with other contributing factors, such as decreased resistance of the stomach lining to acid; continued use of nonsteroidal anti-inflammatory drugs (NSAIDS), such as aspirin, ibuprofen, and naproxen; and smoking) (http://www.med.umich.edu/1libr/aha/aha_gasulcer_crs.htm).
    So, the reason that Marshall and Warren were able to overturn the prevailing consensus view on the cause of stomach ulcers is that they were very observant and very persistent (and Marshall was very brave in drinking a bacterial culture). And the prevailing view wasn’t entirely wrong. That is why there is a market for proton pump inhibitors (http://en.wikipedia.org/wiki/Proton_pump_inhibitor).

  144. Marcus:

    Dean_1230: Our extrapolation does not come from “extending a line” but rather from fundamental underlying physical processes resulting from understanding the likelihood of continued CO2 emissions, effects of the resulting increased radiative forcing, rates of ocean heat uptake, etc. The warming from 1900 to 1940 had a significant natural component (see Figure 4 from the Summary for Policymakers in either the 3rd or 4th Assessment Reports). There was no apriori reason to have expected said natural component to continue increasing (and indeed, it did not).

    On your 2nd point: Could you repeat your analysis using a 5-year moving average? Using the GISS dataset I get a rate of temperature increase from 1976 to 2004 that is double that of 1910 to 1941 when using such a moving average, which given year-to-year natural variability is much superior to taking single year differences (though I think the GISS dataset shows more recent warming than the HadCrut3 because of Arctic inclusion, so perhaps it is a dataset difference: indeed, looking at HadCrut3 the difference is only a 14% increase even with the moving average).

  145. John Mashey:

    re: #132 Keith
    [I am of course not a climate modeler, although I used to help sell supercomputers to them.]
    =======
    To finish off the car issue: they certainly do real crash tests, but the real crashes they do are a minuscule fraction of the virtual crashes. For example, at one point in the design of some model of the Ford Taurus:
    a) If there was a crash at a particular narrow range of angles
    b) The virtual crash test dummy pitched forward
    c) then bounced back
    d) and at that point, the left roof strut collapsed in such a way as to smash its skull.
    If I recall right, they actually fixed this by removing metal. They gave us a terrific visualization of this. Of course, these days, they do a lot more, as the crash test dummies come in much more varieties, and are much better simulations of humans.

    ======
    From what I can see, from the literature, and from talking to people, climate science modelers are always talking about uncertainties and trying to bound them, and always talking about effects of different scenarios, and doing sensitivity analyses. When I was talking to people to NCAR or GFDL, or NASA, or… there were plenty of discussions of the form:

    1) We have some data, we feel good about X, we wish we had more of Y.

    2) We have rock-solid scientific knowledge HERE, and we’re sure of that, and we’re not so sure of THERE.

    3) For THIS, we already get good results from your computers, and the main issue is improving scientific understanding. For THAT, we desperately need more Gigaflops, and when can we get a Terabyte of main memory? I.e., for problems where better resolution is really needed to see the effects.

    Anyway, maybe some climate scientists trust models with no careful evaluation, but I just haven’t seen that.

    =====
    However, the likely problem you’re running into is, that if you go back to original post, you unfortunately came across as saying:
    - models don’t work in your domain, so they’re untrustworthy in general
    - consensus is usually wrong [and use an example often used by denialists:
    Google: scientific consensus ulcer climate

    And people hear this all the time, from a range of people from possibly-reasonable ones who are new to this domain, and those who are clearly denialists, paid or otherwise.

    I'm amazed that folks like Gavin are as patient as they are.

    Let me pick two theories closer to your domain:

    1) Evolution
    2) Smoking increases the risk of disease in humans

    Is there a consensus among bioscience/medical researchers that those are correct?

    Do you subscribe to them? Why? You wrote:
    "Sorry, but as a rule of thumb I’d say the scientific consensus is more
    often wrong than right. So I think we should very much put to bed the
    idea that scientific consensus has any scientific merit."

    Has evolution (overall) been proved by a simple physical experiment? {well, I guess one could argue for Sabin vaccine as an example, maybe, but that's about the same as seeing the absorption effects of CO2 in humid or dry air, which people have done.]

    How about smoking? As far as I know, nobody has done the simple physical experiment of taking two groups of 12-year-olds, telling one group to smoke for the next 40 years, predicting how many will get sick (much less which ones), and waiting to see. [Of course, they do their best with epidemiological studies to simulate that effect.]

    I would claim that the consensus on AGW among professionals is every bit as strong as those regarding evolution and smoking. Of course, in all 3 cases there are a few dissenters plus a strong contingent of outright denialists.

    Finally, here’s a very thoughtful piece of Naomi Oreskes on the general nature of consensus and proof in science, using this as an example:

    http://www.ametsoc.org/atmospolicy/documents/Chapter4.pdf

  146. Philippe Chantreau:

    Re 132: the experiment is happening as we speak, Keith. Of course, by the time the results will all be in and duly analyzed, the available options may be quite limited. So what do we do?

  147. TonyN:

    Re 134: Hank Roberts

    Hank: I really agree with you, although I’m not so sure about the ‘oxy’ bit. What worries me is that when you look at the Acknowledgments section of Warm Words (page 4) it appears that the project was funded by big oil. Can they be trusted?

  148. tamino:

    Re: #136 (Chip Knappenberger)

    Interesting analysis. I would have supposed that a 16th order polynomial would have been over fit… I suppose the BBC reporter Richard Black could have used a 16th order polynomial as the basis for his statement, but I imagine that Gavin probably would have talked him out of it, as I would have hoped Gavin would have talked him out of comparing the 1979-2006 rise with the 1900-2006 rise since the post-1979 rise was more or less linear while the post-1900 rise was more complex and thus the comparison is out of context. One could just as well argue that the 1900-1945 rise accounted for more than half of the overall rise, but that would seem to produce a paradox…

    I said earlier that either you were confused, or you were trying to cause confusion. I see now that the latter is true, and the former may be as well.

    It doesn’t matter what smoothing method you use, as long as it has enough degrees of freedom to capture the actual signal on decadal time scales. The 16th-order polynomial suffers from minor overfitting, especially at the edges. However, trend analysis indicates that the correct polynomial order for this time scale is 8th-order. I also applied a low-pass filter, a “running polynomial” fit, and a wavelet transform. Also, 1945 isn’t really the peak mid-century year for smoothed GISTEMP data, 1943 is a better (slightly warmer) choice.

    For the 8th-order polynomial, 1900-1943 is only 26% of the 1900-2007 difference, while 1979-2007 is 64%.

    For the lowpass filter, 1900-1943 is only 40% of the 1900-2007 difference, while 1979-2007 is 56%.

    For the running polynomial fit, 1900-1943 is only 36% of the 1900-2007 difference, while 1979-2007 is 67%.

    For the wavelet transform, 1900-1943 is only 37% of the 1900-2007 difference, while 1979-2007 is 66%.

    In every case the 1900-1943 (or 1945 if you prefer) change is LESS than half the 1900-2007 change. In every case the 1979-2007 change is MORE than half the 1900-2007 change.

    Your attempt to characterize the relative warmings 1979-2007 (or 1900-1943) relative to 1900-2007 using a straight line or parabola is naive at best, disingenuous at worst. All you really have to do is look at the data to know that this is wrong.

    Your continued protests, in the vain hope of casting a pall over Gavin’s claim that “more than half the warming has occured since 1979,” is …

  149. Steven Marx:

    As a teacher of a college course in argumentation and research focussed for several weeks on the issues of climate change, I refer students to your site for resources of information and persuasion. I also refer them to climate sceptic websites and require them to compare and analyze reasoning on both sides. As an organizer of Focus the Nation (http://focusthenation.org), I try to educate all members of my community about the seriousness of the problem and get them to take political action to do something about it.

    In both those capacities, the most persuasive and powerful of climate sceptics I’ve come across is Marlo Lewis. He’s an employee of the right-wing Competitive Enterprise Institute and a darling of National Review for whom he writes regularly and of the right-wing blogosphere. He seems knowledgeable and good humored and he doesnt write with the hysteria of many of his allies. He was apparantly sent an email last summer by the head of the Renewable Energy Institute that has been widely publicized as evidence of the effort of climate change activists to intimidate sceptics.

    Despite his prominence, a search of your site and of the web provides no discussion of his work or his role, other than to dismiss it because of the source of his funding. I find this an inadequate critique to present to students who are sincerely looking to find ways to make up their own minds.

    Has anyone associated with Real Climate read, analyzed and written about Marlo Lewis?

  150. CobblyWorlds:

    #125 Timo Hämeranta,

    This year’s “weather event” that provoked the massive loss hasn’t been attributed to CO2 forcing. But that neglects the role of AGW in bringing about the conditions for such “weather” to “take advantage” of the ice cap state and precipitate rapid changes.

    That paper you cite is about oceanic mass – i.e. water. i.e. http://www.agu.org/sci_soc/jh/2007-04-16.html#two

    Rotherock/Zhang’s modelling work suggests an underlying trend of ice loss due to surface warming that precedes the “shift” in the AO.
    http://psc.apl.washington.edu/zhang/Pubs/rothrock_zhang_2004JC002282.pdf

    Rigor and Wallace find a role for changes in the AO in the rapid loss since the 1990s.
    http://seaice.apl.washington.edu/IceAge&Extent/Rigor&Wallace2004.pdf

    I thought the initial changes in the Arctic in the 1990s were attributed to the mode of the Arctic Oscillation (AO) and that Baldwin has reported a downward propagation of mode changes from the stratosphere. So I am puzzled as to what you mean with regards the ocean.

    Due to the loss of perennial ice (which by definition takes years to re-grow) and the underlying warming trend, the damage has already been done. Unlike many other climatic systems the ice-cap has a substantial multi-annual memory in the state of the perennial ice, which seems to me to best viewed as a damping factor. Lessen that damping factor and we see an increase in ice area loss rate under the influence of summer ice-albedo feedback.

    As an aside:
    I just cannot believe the equine flagilation to which the sun has been subject.

    To re-iterate Gavin’s assertion that there is no trend in neutron counts: http://cr0.izmiran.rssi.ru/clmx/main.htm
    Scroll down, select your period, and plot whatever periods you want. You can also go hunt around the other sites on the links. And if you’ve forgotten what the temperature has done over the period you’re looking at see my post 82 for links to graphics of the 3 main(only?) land/ocean datasets.

    Anyone know what the spikes are around 03:00-06:00 and 14:00-2100 28/02/55? You can get that in hourly resolution.

  151. Keith:

    John. OK. Now I understand the aggressive nature of some of the commenting. I stand by my analysis of the models though. We’ll just have to disagree on that one. My argument around experimentation is about the forward experiment. The prediction part. We too have models that explain huge amounts of data but when new data is generated they fall over. That’s why I find this debate so interesting. I haven’t seen anything being done that explains why they are so different and are able to predict the future with such small errors. I shall read some more. There could be some great stuff in there for my own work that I simply haven’t fully grasped.

    Evolution. Ah I love this debate. The intelligent design bozos just don’t get it. I work with bacteria and viruses and see them mutate every day under selective pressure. Evolution is all about selective pressure. There;s considerable debate about whether selective pressure is pure evolution since it’s not random, you are putting a forcing(!) onto the system. The random bit is where some molecular biologists get worked up but I see it in terms of the selective pressure forcing a random mutation in order for the organism to maintain function and not die. So yes we can watch evolution in action particularly in the field of viruses and bacteria where the experiments are easier. So the consensus works here. Evolution in action. Fantastic stuff.

    Smoking. This is a curious one. I think that a number of groups have pretty much shown the toxicology makeup within tobacco smoke and the effect on lung cells in vitro and in vivo. It’s a pretty clear experimental result that certainly supports the epidemiology (sp?). Although the one part that is curious is why it has more effect one some people than on others. SNPs are the current fav target for this observation but there’d no consensus yet. But the experiment using smoke on real (non-human) living animals is pretty clear. Not done much now except in some countries where that animal experiment is seen as ethical. I think it’s pointless myself. The data is pretty clear here.

    Marcus. I can agree with you but I might add that I view that science is build on data and observation. Otherwise we wouldn’t have the urge to keep doing experiments and discovering something new. Which is why I turn up every day to work. I’m doing something that nobody has ever done before or even thought of. Which is nice! Oh and Mayo’s work is cool but he picks the easy proteins that have good sequence homology with proteins of known structure. He’s had a few shockers where’s he’s got the structure right(ish) and then got the function totally wrong. That’s why Reetz’s more recent work was so outstanding (and confusing)

    David B. Yip. indeed I have read the bit at the start. That’s how I started reading this site.

    Oh and Chuck. Thanks. It’s a great story. Fantastic piece of science and a well deserved Nobel Prize.

    But I think I’m done commenting now. It seems to be far too polarised for my liking. I was taught in my earlier scientific career to be inquisitive and questioning. I still think that’s a good thing. But thanks for all the info and the comments everybody. Good luck with those models. I watch with interest.

  152. Ray Ladbury:

    Keith,
    On the one hand, you say that you want some sort of “experiment”. What would you suggest? Much of the physics that goes into the models has its basis in the lab, but evidently that is not enough for you. The thing is that it is rather difficult to fit a planet into a laboratory. We have no experiments that support plate tectonics. We have no lab experiments to support much of Earth science, astronomy, astrophysics… We do have lab experiments to support some, but not all of the tenets of evolution. Even my thesis experiment in particle physics could not be described as yielding unambiguous experimental results–they had to be interpreted statistically. In short, science has moved beyond your limited view of it–and it still works. Inductive science is every bit as valid as laboratory science, and it yields conclusions every bit as strong. Moreover, even with laboratory experiments, ultimately, we must conclude what the experimental results support. I strongly urge you to learn more about the scientific method. It will make it easier for you to appreciate research outside your field of expertise as well as making you a better chemist.

  153. Svet:

    Re: #82 CobblyWorlds
    “the three surface temperature analyses depict similar rates of warming over long time scales, and discrepancies in recent decades are largely consistent with differences in methodology.”

    The problem of course is that HadCRUT3 and GISS are telling totally different stories for period 2001-2007. If “differences in methodology” can do this then something is very wrong somewhere. What can the layman do when confronted with two such different stories? If this discrepency is not quickly resolved in an objective, credible fashion then intelligent discussion of the subject is going to become very difficult. “Sceptics” will favour HadCRUT3 and “believers” will choose GISS and both will have perfectly defensible positions but nothing will be resolved.

    [Response: look at the maps. it is readily apparent where there are differences, and why. No mysteries there.... - gavin]

  154. Steve Bloom:

    Re #125 (original comment by Timo reproduced below for convenience):

    Timo, IMHO the kind of trick you just tried to pull is very disrespectful of others. You imply something momentous about the sea ice trend, but a look at the NASA press release (and notice how I link to the document I’m quoting so others can easily confirm what I say?) finds this passage:

    ‘”While some 1990s climate trends, such as declines in Arctic sea ice extent, have continued, these results suggest at least for the ‘wet’ part of the Arctic — the Arctic Ocean — circulation reverted to conditions like those prevalent before the 1990s,” he added.’

    IOW, nothing at all about the sea ice. Imagine that.

    The paper actually is very interesting, but the reason a press release was issued six months after the paper was published was to announce that the AO now seems to be flipping back to the 1990s state. Its main point is that the warming trend hasn’t yet taken complete control of the Arctic Oscillation:

    ‘Morison said data gathered by Grace and the bottom pressure gauges since publication of the paper earlier this year highlight how short-lived the ocean circulation changes can be. The newer data indicate the bottom pressure has increased back toward its 2002 level. “The winter of 2006-2007 was another high Arctic Oscillation year and summer sea ice extent reached a new minimum,” he said. “It is too early to say, but it looks as though the Arctic Ocean is ready to start swinging back to the counterclockwise circulation pattern of the 1990s again.”

    ‘Morison cautioned that while the recent decadal-scale changes in the circulation of the Arctic Ocean may not appear to be directly tied to global warming, most climate models predict the Arctic Oscillation will become even more strongly counterclockwise in the future. “The events of the 1990s may well be a preview of how the Arctic will respond over longer periods of time in a warming world,” he said.’

    I’d really like to know how you managed to read an opposite meaning into this material. If it’s just that you didn’t understand it, I think you need to get out of the climate science gate-keeping business.

    Original comment by Timo:

    About Arctic sea ice please see:

    Morison, James, John Wahr, Ron Kwok, and Cecilia Peralta-Ferriz, 2007. Recent trends in Arctic Ocean mass distribution revealed by GRACE. Geophys. Res. Lett., 34, L07602, doi:10.1029/2006GL029016, April 4, 2007

    “…The spatial distribution and magnitude of these trends suggest the Arctic Ocean is reverting from the cyclonic state characterizing the 1990s to the anticyclonic state that was prevalent prior to the 1990s. ”

    Nasa news November 13, 2007

    “The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.”

  155. Timothy Chase:

    On “Scientific Consensus”

    There is a great deal of interdependence between scientific disciplines – I have pointed out as much in relation to Duhem’s thesis previously. Typically, if someone is to test a given advanced theory, there will be a great number of other, earlier scientific conclusions which one will have to presuppose are true, even though it is at least “possible in principle” that evidence at some point may be discovered which would require that individual to abandon one of those background assumptions.

    The test of a hypothesis M will generally be of the form if A&B&C&…&M then e, and M is regarded as failing the test if not e. But if any of the background assumptions were in fact false, then M might be true with not e or false with e, and the test would be an invalid test of M for either the purpose of confirmation or disconfirmation. Or to put it another way, in principle at least, the test is a test not of M but always of A&…M.

    *

    Likewise, the more broadly integrative theories will rely upon the conclusions in a wide variety of disciplines, implications in a wide variety of of disciplines and have explanatory power in a wide variety of disciplines. At the same time, modern science requires a large division of cognitive labor. It is divided into fields, disciplines, sub-disciplines and sub-sub-disciplines. Few people can achieve any real expertise in more than a handful or so areas.

    As such, while someone may be able to state as a matter of their own expertise that a given theory or (narrower) theoretical principle which cuts across a wide variety of disciplines is well-supported by the evidence in their field as a matter of their own expertise, they will generally be unable to do so in a variety of other fields where that theory or principle applies. Likewise, they will generally tend be unaware of many of the issues which had previously decided in favor of the principles which their discipline takes for granted – except at a fairly cursory level.

    As such, experts throughout the scientific endeavor generally have to rely upon points that are at least tacitly dependent upon a form of scientific consensus — whether they are aware of this or not. Its unavoidable.

    But at the same time, it generally isn’t something which they have to be all that aware of – precisely because the principles which have become part of the well-established consensus are well-established. We generally become self-consciously aware of expert consensus and the need for it only at the interface between the scientific community and the broader community in which it is embedded.

    *

    There have been points at which the very notion of a “scientific consensus” has come under attack, and no doubt there will be in the future. Typically, such attacks will rely upon an equivocation between appealing to a scientific consensus and “appeal to the majority,” or alternatively, assume that an appeal to the scientific consensus is an appeal that is independent of the actual evidence upon which a decision should be based.

    However, the scientific consensus is a consensus of experts, each acting as an expert alongside other experts in his or her own field. These experts are gathering evidence, generating theories, forming hypotheses, making predictions – and testing theories – and their views become relevant to and incorporated into the consensus on a given issue only to the extent that their area of expertise is relevant to that conclusion. As such, the scientific consensus is evidence-based.

    It is not simply a form of an “appeal to the majority.” It is, in essence, an appeal to a congress of individuals who are acknowledged and tested experts in their respective fields – where the weight given to any voice is a matter of the relevance of the expertise.

    Given the collective extent of those fields, this exposes the conclusions to a far larger body of evidence and tests than would be possible by means of any one field considered in isolation from the rest. Consequently, the justification for a conclusion arrived at by means of the congress can be far greater than that which the conclusion would receive if it were simply supported by only one or a handful of disciplines.

  156. Julian Flood:

    quote Actually I just scrounged a section from Salter and Latham’s paper. Highly recommended. unquote

    Ooops, silly me. That should be 10^18 drops/sec, but I suppose that was so obvious no-one bothered to correct me.

    From the same paper: For a given amount of water, a large
    number of small droplets make clouds reflect more than a small
    number of large drops. Increasing global cloud albedo by only
    1.5% would produce a cooling sufficient to offset the warming
    due to a doubling of current CO2.

    Google on Palle. See the reduction in albedo in the Earthshine observations and ponder why it’s getting warmer. (Then you can wonder why the albedo is dropping and, as I did, wonder about pollution of the ocean surface reducing droplet production and — just thought of this — the increase in critical relative humidity caused by surface changes on the CCN. But I digress.)

    It’s getting warmer because it’s getting sunnier.

    JF

  157. Richard Ordway:

    Okay, More about all this peptic ulcer stuff and global warming consensus.

    The old peptic ulcer consensus appears to have been partly right anyway, and then it was peer-review (seemingly working extremely slowly on the issue in this case (no one really saw a big need to challenge it) which added to the knowlege to complete the story.

    Wikipedia states (and to refute this you need links and just not “I work on this in the lab so I know better than you do” response).

    Wikipedia states under the heading of “Peptic Ulcers”:

    “As much as 80% of ulcers are associated with Helicobacter pylori, a spiral-shaped bacterium.

    Tobacco smoking, blood group, spices and other factors that were suspected to cause ulcers until late in the 20th century, are actually of relatively minor importance in the development of peptic ulcers.
    [4]
    Ulcers can also be caused or worsened by drugs such as Aspirin and other NSAIDs. Wikipedia
    http://en.wikipedia.org/wiki/Peptic_ulcer

    Okaaaay, so what we got here?

    1) The old consensus theory was of relatively minor importance…but still a factor nonetheless…so all those “consensus quacks” were not totally wrong and indeed right in some cases.

    2) ~80% of the ulcers are caused by the nasty helicopter errr (Helicobacter pylori-sorry, I used to fly). Wow, that leaves 20% that are not. So again, our consensus quacks are not all wrong.

    “Ulcers (peptic, I presume) can also be caused or worsened by drugs such as Aspirin”. Hmmm, that is not our “helicopter” super bug either.

    The bottom line is that the consensus view was *partly right*…and it was by peer-review that the other 80% or so came out.

    This global warming issue is and has been since the late 1960s at least, by contrast, actively and massively investigated even now in peer-review…

    but the challenges do not stand up even though the challengers have had almost unlimited funding (from the eager (desperate) energy and transportation industry, that the last I heard earns over one billion dollars a day (for excess cash to spend on dailiances like funding competing scientists).

    So, this peptic ulcer, thingie, in my opinon, is a strawman…like comparing apples and oranges.

  158. GlenFergus:

    #130

    Whoops, fixed now.

  159. Rod B:

    A little belated aside: Lawerence Brown’s (15) use of “the now famous statement by Jack Nicholson’s character in ‘A Few Good Men’ applies- “They can’t handle the truth!”’ to refute the so-called deniers seems a little odd, being as how Nicholson was the authoritative liar in ‘A Few Good Men’.

  160. Ellis:

    110
    [Response: This is a fallacy. Thanks fot the warning.

    Given that Snowball Earth and the Cretaceous hothouse clearly delineate the bounds of natural variability, your argument is equivalent to saying that nothing less dramatic than the freezing over of the oceans or the raising of the temperature by 10 deg C or so can possibly be attributed to any forcing. This is absurd.
    The use of a straw man is not going to dissuade me from my opinion.

    The issue is not whether any climate change was bigger or smaller than today’s - it is whether it can be explained, and whether that explanation has validity today. So while orbital forcings, giant volcanoes, asteroids, Heinrich events etc. have all caused dramatic climate changes in the past, none of them are relevant to today. I am not sure that it follows that none of them are relevent today. Our climate is defined by the orbital forcings, however, I understand your point that these forcings change little on centennial time scales.

    Just because large forest fires have occurred naturally in the past, does that imply that arson cannot happen? No, but does an arson's match in San Diego imply global warming?

    Or that if we see someone walking away from a fire with an empty kerosene can and some matches, we can’t logically infer that he may have had something to do with it? - gavin]

    I don’t object to the claim that a dissproved alternate theories bolsters your stance, I do object when this is taken as proof of your theory.

  161. Hank Roberts:

    Google Scholar finds:
    http://www.agu.org/cgi-bin/wais?ii=A43B-01
    2007 Joint Assembly

    “AB: The Earth’s albedo is one the least studied of the fundamental climate parameters. The albedo is a bi-directional property, and there is a high degree of anisotropy in the reflected light from a given surface. However, simultaneously observing all points on Earth from all reflecting angles is a practical impossibility. Therefore, all measurements from which albedo can be inferred require assumptions and/or modeling to derive a good estimate. Nowadays, albedo measurements are taken regularly either from low Earth orbit satellite platforms or from ground-based measurements of the earthshine in the dark side of the Moon. But the results from these different measurements are not in satisfactory agreement. Clearly, the availability of different albedo databases and their inter-comparisons can help to constrain the assumptions necessary to reduce the uncertainty of the albedo estimates. …”

    and

    “The Darkening of the Earth’s Albedo at High Northern Latitiudes During 2006 as Measured by MISR

    “AB: The deseasonalized anomalies in the time series of globally averaged top-of-atmosphere spectral albedos measured by MISR have now been analyzed from 2000 through 2006. The initial record from 2000 through 2005 showed little in the way of significant anomalies. However, a significant decrease was detected during mid 2006. This anomaly disappeared by the end of 2006 and does not appear to be an instrumental or sampling aberration. The 2006 anomaly is restricted to latitudes north of 40° during late Spring and early Summer, and is large enough to affect the global annual average. …”

  162. Larry:

    Re # 116

    I don’t follow the graphs you reference, about 12 million years ago it shows anti-artic reglacialtion?? Not melting?

  163. Joseph O\'Sullivan:

    The contrarians might be fighting away in the public and legislative arenas, but they are getting walloped in the courts.

    The latest is the Federal Courts rejection of the new mileage standards
    http://www.nytimes.com/2007/11/16/business/16fuel.html?_r=1&ex=1352955600&en=f428086d78492032&ei=5088&partner=rssnyt&emc=rss&oref=slogin

    For analysis
    http://warminglaw.typepad.com/my_weblog/

    This follows the court’s acceptance of climate science under the Clean Air Act at the Supreme Court, state’s right to regulate greenhouse gases in Vermont, the effects of anthropogenic global warming on the ecosystem involving corals and polar bears and Pat Michaels withdrawal as an expert witness.

    The one thing the legal system has that scientists might appreciate is the concept that losing parties can’t keep fighting. The courts tell them that they have lost and they have to get over it. Too bad the legal concept of finality can not be applied to other areas.

  164. Wayne Davidson:

    #125 and 150. It was quite clear, the weather systems preceding and during the big ice melt, especially the pressure systems, were quite familiar, nothing new there. By simple logic,
    if the systems were similar, then why the big melt of 2007? The answer is temperature,
    giving a true departure from recent experience, temperature anomalies were strongly consistently warmer. The same pressure system of this summer past, a generally wide anticyclone, is still here now, resurfacing the Arctic ocean with very thin ice, but over the last recent years the temperature landscape was dramatically different, despite similar pressure dynamics. It was not the first time a wide anticyclone dominated North of Alaska during summer, yet the ice melted massively, unlike many previous years. The only possible conclusion: more heat was circulated in the usual ways through the pressure systems .

    Gavin cited 2007 on track to be #2 warmest worldwide, now imagine if a Low pressure was persistently North of Alaska precluding the melting of millions of kilometers of extra ice, 2007 would have been #1 warmest if it wasn’t for the clear summer Polar air. Ongoing data show the Arctic atmosphere in general warmer at multiple levels, the only source of extra heat above the surface is tri atomic gases and their feedback companion water vapour. Remember the solar argument completely flunks when average temperatures are about 10 degrees C above in near darkness., there are no other explanations or observations identifying another source of heat, not even the ocean, at best -1 C warm during much of the year.

  165. Imran Can:

    #130
    “I’m rather older than 8, but I can draw graphs.”

    Glen – obviously not – you forgot to correct for the fact that the 2001 IPCC graph has a baseline of 1990 … as opposed to a 1961-1990 mean basline for the HadCrut data. Maybe you could re-post the graph with the points correctly plotted ?

    But I tend to agree with Gavin – there is nothing definitive about these points (even though they are below the range) because the recent flat period of 6 or 7 years doesn’t mean the overall AGW theory is wrong. But it does remind us that we have to act with a little humility and remember to keep our uncertainty ranges wide.

  166. Keith:

    Oh God. I just can’t seem to get away from this.

    Ray. You are right that many areas of science where experimentation is difficult and so we have to reply on statistical methods and so forth. My point has been, all along, that I am uncomfortable with the a heavy reliance on models. That is based on my own experience in my area which may or may not have relevance in the field of climate change. I should point out that I am not actually trying to deny AGW or suggest that the work that is being done is flat out wrong. I simply have some doubts about the ability to predict the climate in 50 years with what I see as a limited data set. I’d love to see more physical experiemnts done to test the models. As someone pointed out earlier, the predictions could actually turn out to be too conservative and we may be underestimating things. That is a greater concern than us getting away with not much happening. That is what I am trying to get at. It’s truly superb work that you can computationally generate a model which fits so much data. It’s the bit after that where thigns get interesting. The prediction bit. That is the meat of this area in my opinion. The really interesting bit. In my own field there are literally dozens of ways of making a molecule using known methods and techniques that have data and consensus and everything you could possible want. But the real challenge is actually doing it. Because sadly, as soon as we try to do anything complicated the known reactions often fail (despite having maybe 100 years worth of experimental exmaples on other substrates)and we have to try out dozens of new routes to solve the problem (that’s actually one of the massive appeals for me). Small changes make big differences. It’s the reason why nature makes Brevotoxin B in minutes (after a few million years evolution!)and KC Nicolaou and his group took more than 10 years using synthetic methods and numerous routes.

    So going forward I’d argue that my view is not limited, Ray. It may be different to yours but if you were so work in my field you might see that our bias is heavily weighted towards experimental science. We’re absolutely nowhere in terms of applying physics to describe apparently simple chemical reactions. Ahmed Zewail has shown that even some of the most basic ideas we had were incorrect when applied to our most simple reactions so perhaps you can understand why I struggle to be comfortable with there being less experiments done in your field.

    I suspect that your view of the scientific method and mine are not the same as a result of the respective fields we work in but I agree that it would be instructive to look in more depth at your methodologies since clearly you generate, collect and interpret data differently. Perhaps you would be willing to do the same and consider how it differs outside of your own field? Maybe you could learn something yourself? You never know. Good luck with the research.

  167. Barton Paul Levenson:

    Keith writes:

    [[So,a great model. But they STILL go and do the actual crash at the end. Just to be sure. So there we have an example of a model that works almost perfectly. We have models in pharma that don’t. So where is the experiemntal work to show where the climate model is? And that is my point, even if it seems to be unresolvable becasue the experiment can’t be done. That is why I am a little skeptical on the output of the models. But look on the bright side, I’m very close to being a believer. Just one experiment!]]

    The crucial experiments were done in 1859 by John Tyndall. Google for that.

  168. Barton Paul Levenson:

    Dean posts:

    [[It is my understanding that the cooling of the 40s and 50s was due to volcanic activity, but what was the earlier temperature rise due to? ]]

    The cooling of the 1940s and ’50s was due to aerosols created by industrial activity, not volcanoes. The global warming from 1900 to 1940 is partly attributable to the sun, which increased slightly in luminosity over that period.

  169. Barton Paul Levenson:

    Keith writes:

    [[I was taught in my earlier scientific career to be inquisitive and questioning.]]

    Implying, of course, that we (and perhaps climatologists in general) are not.

  170. Barton Paul Levenson:

    JF writes:

    [[It’s getting warmer because it’s getting sunnier.]]

    Except that it isn’t getting sunnier. We’ve been measuring Total Solar Irradiance with satellites for decades. The Sun hasn’t gotten noticeably brighter in 50 years.

  171. Anthony Hawes:

    I am a scientist who performs experiments to test hypothesis, in a field with very few variables. We regularly attempt to model outcomes, albeit with limited algorithmic scope, an always fail to adequately reflect the real world outcomes. Sure sometimes we get in the ballpark – and perhaps that is what is being argued here by the author – that the ballpark ain’t a bad result in the climate change field. But hang on – we can’t even relably model climate days ahead (often not the carpark). Surely the extreme complexity in the climate system will never be adequately modelled for future outcomes? Please note that I am desperate to know where the AGW issue is headed as it will directly affect my business. There is a large body of data, and so much of it conflicting (even in the IPCC reports – each of which I have read completely). So, I direct readers to this link (http://hadobs.metoffice.com/hadat/images.html) which for me is the crux of the issue: that is, the emperical data is not all that convincing wrt AGW. Actual data is a wonderful thing and my extensive reading on the subject of the temperature record suggests the link is the most reliable data source around. Warmer it is getting but out of control?
    Can anyone comment on this data?

  172. Cobblyworlds:

    #160 Ellis,

    Gavin was clearly not engaging in a Straw-Man argument.
    Hothouse – Snowball is the natural range of the Pharenozoic. In order to support your argument you must specify what bounds of natural variability you are referring to. So as you seem not to prefer the bounding Gavin points out, perhaps you could define what you see as “the bounds of natural variability”.

    You state (with respect to orbital forcings, giant volcanoes, asteroids, Heinrich events etc) that: “I am not sure that it follows that none of them are relevent today.” If you are not sure then it implies that you have reason, thus you should be able to detail such reason in terms of mechanism and evidence…
    In other words – please do so.

    You state: “The theory of AGW rests only on one principle, as far as I can tell, that the warmth of the past century is outside the bounds of natural variability.”
    AGW clearly does not rely upon the current warming being outside the bounds of Holocene variance.
    The physics of CO2′s impact on OLR suggest that the more CO2 we put in the atmosphere the more warming we will have. So if by evidenced mechanism and supporting observations we can establish good cause to finger CO2 as the culprit, then it matters not whether we have left the bounds of Holocene variability. What matters is whether atmospheric CO2 levels can be driven high enough to attain that state in the future. I don’t need to be contending with an actual housefire to spot the danger of a smouldering cigarette in a waste-paper bin. (That’s an analogy – housefires and cigarettes are not significant factors in AGW)

    Then you take Gavin’s clear analogy and attempt to dismiss by taking it literally. Which whilst worth noting is unworthy of comment.

    The ball is clearly in the “Sceptics” court, I use quotes because I don’t think that there are real sceptics of the theory of AGW anymore (denial is not scepticism). The intelligent sceptics have long since moved from claiming the current warming isn’t due to CO2 onto questioning what the impacts will be and whether it’s worth acting. The “Sceptics” must provide coherent alternate theories that explain observations. They must produce sound alternate explanations for observed changes, stating “natural” is no more an explanation that Intelligent Design’s “God did it”.

    So where does this leave us?

    We have warming, backed up not only by a range of different measuring techniques – from boreholes to satellite thermal emission from the atmosphere, but also by the global average trend in water vapour changes. The increase in ocean heat content shows that the warming is significant. So why is there a warming if not due to CO2?

    We have concomitant observations that are expected with CO2 (diurnal range, vertical profile of changes – stratospheric cooling, tropospheric warming). So why do we have these observations if not due to CO2?

    To dismiss CO2 you have to address this pattern. If CO2 isn’t to blame, what is causing the warming and the observations I outline? The stance “It must be anything but CO2″ does not constitute a theory.

  173. Imran:

    #158
    Glen – I don’t think you got it right on your second attempt either. Let me walk you thru it …. maybe we can just do 1 point …. say 2006. The HadCRUT average for 2006 is 0.42 (anomaly above te 61-90 mean). But the difference between the 1990 value (which is the IPCC graph baseline) and the 61-90 mean is ~0.25. So the point you need to plot on the IPCC2001 graph is 0.42-0.25 = 0.17. For the year 2006. Try plotting that.

    Its not hard, but I guess sometimes we get the answer we want to get.

  174. Chip Knappenberger:

    Re comment: 148.

    I must hand it to you, Tamino. You’ve managed to coax more warming out the period from 1979 to 2006 than any other analysis I’ve ever seen. Since the BBC’s Richard Black gave the total rise from 1900 to 2007 as 0.8ºC, your four 8th order polynomial fit methods yield on average a 1979-2006 temperature rise of about 0.51ºC (with one solution producing as much as 0.8ºC *0.67=0.54ºC of warming. Since the difference between the absolute greatest anomalies (0.526 in 1998 and -0.037 in 1985) is 0.563 in non-endpoint years (from the HadCRUT3v), you are doing pretty well to produce a solution yielding 0.54ºC.

    In your various non-linear (and sometimes smoothed) analyses of the overall period, 1900-2006, the behavior during the middle years from 1945 to 1979 acts to reduce the estimates of the temperature rise between 1900-1945 and raise the estimates of the rise from 1979-2006 from those values that would be calculated from looking only at those periods independently.

    As you mentioned, all you really have to do is look at the data to know that the post 1978 rise is not greater than the early century rise. Move the starting point back a few years or wait a few more years for warming temperatures to continue and the story will certainly be different. But as of right now, the temperature rise from 1979 to 2006 is not greater than the temperature rise from say, 1910 to 1945 (however you care to fit those periods independently).

    -Chip

  175. Keith:

    No Barton I was not implying that at all. You really do want to get those digs in don’t you. [edit]
    I was merely stating that I am inquisitive about this particular issue which I why I have chosen to comment, read source material and participate in this discussion. I think it’s quite clear that that modellers ask questions too. Try not to be too paranoid mate.

  176. Nick Gotts:

    re #171 (Anthony Hawes) “But hang on – we can’t even relably model climate days ahead (often not the carpark).”

    You’ve read all the IPCC reports and you still don’t know the difference between weather and climate? How did you manage that? I do not know whether tomorrow will be warmer than today here, but I would bet a substantial amount that 16th August 2008 will be warmer than today (I live in Scotland). So you see, changes over a longer period are not always more difficult to predict.

  177. Andre:

    #172 CW, That’s not how it works. perhaps you remember the core business of the scientific method. The falcification. “Science is what we have learned about how to keep from fooling ourselves.” – (Richard Feynman).

    So the bottom line is that the anthropogenic global warming hypothesis can be considered scientifically feasible if no-one is able to falsify it. There is no need to provide a competing hypothesis.

  178. Paul Middents:

    #149 Steve Marx asks “Has anyone associated with Real Climate read, analyzed and written about Marlo Lewis?”

    Gavin was asked last year whether he might comment on Lewis response to the 2006 Time Magazine issue devoted to climate change. He responded:

    “I doubt it. The number of red-herrings, strawmen and simply incorrect statements would challenge even our abilities to keep up with…. ”

    Lewis’ focus seems to be on limiting any climate change response to free market inspired technical innovation. He invokes Lomborg and proudly notes in his bio that Rush Limbaugh and G. Gordon Liddy commentary has been inspired by his ideas. His CV is a complete guide to the denialist repertoire. Real Climate has addressed every one of his “scientific” arguments.

    Lewis is a political “scientist” with nothing to say of value on the science of climate change. Real Climate is a forum primarily devoted to the science even though many discussion threads wander into the politics of responding to climate change.

    I would suggest that Dr. Marx assign his students the task of analyzing Marlo Lewis writings. Other web forums address the politics of climate change and solution/mitigation and should offer some excellent arguments refuting his points. You might submit the best of their efforts to the administators of this forum as a possible entry or more appropriately to one of the forums devoted to the political and economic implications of climate change.

  179. J.C.H.:

    I think posts by John N-G (59.) and John Nielsen-Gammon (91.) pretty much box you in the canyon. You can say you jumped over the mountain to escape, but I don’t think you did.

    Is that the John to whom you were responding in your post (151.)?

  180. Stephen Berg:

    Re: #174, “I must hand it to you, Tamino. You’ve managed to coax more warming out the period from 1979 to 2006 than any other analysis I’ve ever seen. Since the BBC’s Richard Black gave the total rise from 1900 to 2007 as 0.8ºC, your four 8th order polynomial fit methods yield on average a 1979-2006 temperature rise of about 0.51ºC (with one solution producing as much as 0.8ºC *0.67=0.54ºC of warming. Since the difference between the absolute greatest anomalies (0.526 in 1998 and -0.037 in 1985) is 0.563 in non-endpoint years (from the HadCRUT3v), you are doing pretty well to produce a solution yielding 0.54ºC.”

    Chip, Tamino’s estimation of the warming since the late 1970s is quite accurate when you observe this graph:

    http://en.wikipedia.org/wiki/Image:Instrumental_Temperature_Record.png

    To calculate the ~0.5ºC warming since 1978 or so, one can see an average anomaly of -0.1ºC (taking the five year anomaly for smoothness) in 1978 and a +0.45ºC (five year average) anomaly in 2004 when using the 1961-1990 mean temperature. If you do the simple math, 0.45ºC-(-0.1ºC)=0.55ºC. Therefore, Chip, Tamino is not out to lunch in their assessment.

  181. tamino:

    Re: #174 (Chip Knappenberger)

    I’ve got to hand it to you, Chip. You’ve got really big “stones” to tell such a tall tale.

    For your information, I didn’t “coax” anything at all. I simply applied very well-known smoothing methods and reported the results. And only one of the methods I applied was an 8th-order polynomial.

    For those who want to take a look for themselves, look here.

  182. James:

    Re #166: [My point has been, all along, that I am uncomfortable with the a heavy reliance on models.]

    But the basics of AGW theory do not rely on models: they’re just to get a better picture. To take one of the analogies, we can say, sans model, that if you drive a car into a brick wall at speed, then it’s going to wind up as a crumpled mass of sheet metal. A good model would tell you which panels crumple and in which directions, and so allow the design of a car in which the passengers might survive the crash. Still, if you happen to be the driver, the best advice is to avoid hitting the wall in the first place :-)

    Likewise with AGW: without any more model than Arrhenius’ pencil & paper, we can say that adding this extra CO2 is going to cause problems. The models attempt to refine the limits on how big the problems will be, and how soon they’ll happen. In either extreme, with perfect models or no models at all, it’s still better not to hit that wall.

  183. Nick Gotts:

    Re #171 (Anthony Hawes) “So, I direct readers to this link (http://hadobs.metoffice.com/hadat/images.html) which for me is the crux of the issue: that is, the emperical data is not all that convincing wrt AGW. Actual data is a wonderful thing and my extensive reading on the subject of the temperature record suggests the link is the most reliable data source around. Warmer it is getting but out of control?”

    I’m no expert, but the trends in these graphs look pretty convincing to me – particularly the fact that the stratosphere is cooling while the surface and troposphere are warming, as expected if greenhouse gas emissions are responsible for the change. As for “getting out of control”, well assuming you mean “almost gone too far for us to stop”, how would such a graph tell you whether that was the case? A central concern is that there are may be “tipping points” beyond which specific positive feedbacks kick in and AGW becomes far harder to halt – but having any idea how what these might be and how close we might be to them demands knowledge of the climate system, not just looking at what’s happening to the wiggly lines on a few graphs.

  184. CobblyWorlds:

    #177 Andre,

    I don’t undertsand what you are trying to say here. AGW is clearly falsifiable.

    The ongoing most obvious test of falsification for the AGW enhanced greenhouse effect would be if CO2 levels continue to rise but temperatures did not rise. It is a keystone prediction of the theory that more CO2 causes a radiative imbalance in the Earth that causes temperature to rise towards a new higher equilibrium. However as we know that things like ocean mixing, aerosols and other extraneous factors could cause a cooling even with increasing levels of CO2 we’d have to consider the caveats (which as always are all important).

    So far that most obvious falsification is failing – the warming continues. As for the other 2 predictions (without recourse to models) that can be used to test falsification:

    The Stratosphere should cool as outgoing long wave flux through the Stratosphere is reduced
    Observed and ongoing.

    The diurnal range should narrow as night-time heat loss is reduced by reduced outgoing long wave floux reduction.
    Observed up to just after 1980 then stalled. This may appear to falsify, but Wild et al* offer an explanation that suggests another factor (increasing daytime surface insolation) is at play. And if anyone else reading this thinks that’s a cop out, consider the case of a magnet picking up iron filings – that doesn’t falsify the law of gravity.

    Copy of Wild et al linked to in my post 12 here: http://www.realclimate.org/index.php/archives/2007/11/global-dimming-and-global-warming/langswitch_lang/sw
    but note my correction post 21.

    There remains doubt on certain issues – notably practical impacts that the future will bring. It remains my “opinion” that this is the most important issue we face, it’s worth taking a war time approach and really acting on it, but that is mere opinion. The certainty is on the issue of there being a role for CO2 in the current warming (last 30 years at least), the only reasonable answer is yes. And from CO2-warming linkage we can be pretty sure that as we’re emitting more CO2, for as long as we continue to do so, the planets global average temperature will go up.

    To quote from the page you linked to:
    “At the moment, Relativity is once again the only theory still standing. But there’s no way to guarantee that it will stay on top. It isn’t proven. Like all other scientific theories, it is forever tentative.”
    So it is with AGW.

    The ball remains in the contrarists court.
    And a real game of Tennis involves actually hitting it over the net, not shuffling around bouncing the ball off the court. ;)

  185. Steve Bloom:

    Re #162 (Larry): What it shows is that when temps dropped to about 3C warmer than now it was possible for the Antarctic (actually just the EAIS) to reglaciate; i.e., if we let things get back up to that temperature for any significant period of time, we should expect to see it start to destabilize. We are now on a path toward such temperatures, which is why Hansen argues they have to be avoided. Please read this.

  186. Steve Bloom:

    Re #181 (Tamino): Strictly speaking I think they’re lumps. :)

  187. Timothy Chase:

    Since Karl Popper’s “Principle of Falsifiability” is coming up again (Andre’s 177, CobblyWorlds’ 184 and my own 155) …

    Do Scientific Theories Ever Receive Justification?
    A Critique of the Principle of Falsifiability

    Karl Popper states, “Now in my view there is no such thing as induction. Thus inferences to theories, from singular statements which are ‘verified by experience’ (whatever that may mean), is logically inadmissible. Theories are, therefore, never empirically verifiable…

    “But I shall certainly admit a system as empirical or scientific only if it is capable of being tested by experience. These considerations suggest that not the verifiability but the falsifiability of a system is to be taken as a criterion of demarcation. In other words: I shall not require of a scientific system that it shall be capable of being singled out, once and for all, in a positive sense; but I shall require that its logical form shall be such that it can be singled out, by means of empirical tests, in a negative sense: it must be possible for an empirical scientific sytem to be refuted by experience,” (Popper, “The Logic of Scientific Discovery,” 2nd ed., 40-41).

    Now these statements, taken together, require some analysis. Induction, at the simplest level, is normally taken to use the truth of singular statements which are verified by experience to provide justification for general statements. And when the justification for a given general statement is regarded as sufficient, the general statement is regarded as true. This is the general nature of induction. However, Popper is opposed to this view.

    *

    Popper states his opposition in terms of using induction to justify theories rather than individual statements, but this makes little difference. Theories are composed of statements, and to say that one cannot ever regard a theory which has stood the test of induction as true is to say that one can never regard the statements which compose the theory as being true: if all of the statements which compose the theory are true, then one would have no reason to deny the status of truth to the theory itself.

    To see why, let a theory be expressed by the set of statements {h1,h2,h3,…,hn}. Assume that each of the statements in this set is true. Then the theory may expressed by the statement h1&h2&h3&…hn. The truth of this statement necessarily follows from the truth of the statements which compose it. Thus Popper’s Principle of Falsifiability is wide open to a criticism stemming from what is called “Duhem’s Thesis”: the principle of falsification runs into problems since scientific statements are presummably never regarded as true.

    *

    According to Duhem’s Thesis, no empirical hypothesis H can be used to make empirical predictions unless it is conjoined with one or more auxilary hypotheses A. Thus when we use an experiment to test H, where H&A is used to predict an experimental outcome S, the failure to obtain S falsifies H&A. But an isolated experiment does not allow you to determine whether H is false, A is false, or whether both H and A are false. Thus no single test can falsify H by itself.

    However, we can state this even more strongly in the case of the principle of falsification. Since no hypothesis is ever regarded as true, no hypothesis can ever be shown to be false. And if one takes as one’s unit of meaning to be theories instead of hypotheses, one will find that present theories are generally tested by presupposing the validity of theories which have stood the test of time. Unless one assumes that one’s background theories are true, one cannot falsify the theory which is in the foreground, i.e., the theory which one is presently testing. However, the above analysis calls for some examples. I will provide three.

    *

    In my first example, I will be considering a problem involving Newton’s gravitational theory. In his day, the explandatory power of his theory was considered amazing. Given the highest degree of accuracy available in the 1600s, his theory was able pin-point the trajectories of all the planets but one: there existed a minute discrepancy in rotation of the perhelion of Mercury. This one fact was not regarded as in any way falsifying Newton’s theory, though. To test his theory, it had been necessary to bring in other assumptions. For example, when his theory was first checked against the orbit of Mercury, it was assumed that Mercury was the closest planet to the sun. Rather than throwing out Newton’s theory, this assumption was modified.

    For a while, it was thought that there existed a planet Vulcan inside Mercury’s orbit which disturbed this orbit in just such a way as would account for the discrepancy between the original theoretical prediction and the experimental observation. On the basis of this hypothesis, astronomers searched the heavens for the hypothetical planet. As things happened, the additional hypothesis that Vulcan existed turned out to be wrong and Newton’s gravitational theory was abandoned in favour of Einstein’s gravitational theory, in part on the basis of this early experimental evidence, but also on the basis of additional experimental evidence which came after the formulation of Einstein’s theory. Does this mean that Newton’s gravitational theory should have been abandoned in the first place rather than being saved by means of an “ad hoc” hypothesis?

    The Principle of Falsifiability not withstanding, no it does not.

    A similar proceedure was used to predict and ultimately discover the existence of Neptune on the basis of how this outer planet disturbed the orbit of Uranus. Newton’s gravitational theory simply proved to powerful to abandon as hastily as the Principle of Falsifiability would have required. Besides, other explanations of the failure of this one prediction were still possible even once planet Vulcan failed to turn up. For example, a hypothetical oblateness of the sun, and if measurements of the sun’s profile disproved this, then one could hypothesise a rotation in the sun’s interior which would give rise to an oblateness of the distribution of the sun’s mass that would exist only within the sun’s interior, leaving no appreciable evidence at the sun’s surface. Or would it? One might have to ask a student of stellar dynamics.

    When the original conflicts were discovered between Newton’s gravitational theory and the experimental evidence, its discovery was the result not only of Newton’s gravitational theory, but also certain implicit assumptions, assumptions which were not necessarily even stated, but were, in effect, a kind of theoretical background to Newton’s theory. As a result of the predictive power of Newton’s theory under a wide range of circumstances, the scientists of Newton’s age thought it best to modify the background assumptions rather than abandon this powerful theory. With the hindsight made possible by our own advanced age, we may conclude that with respect to Vulcan they were wrong, but in the case of Neptune, they were right. But in both cases, their approach was most reasonable.

    *

    Now I will begin my second example. Roughly at the time that Darwin, it was considered a recognised fact that the earth and the sun couldn’t be more than a few million years old: the only fires known were chemical fires, and alternatively, the only other source of energy which we could conceive of for the sun was due energy being released as the result of gravitational collapse. On the basis of the latter, Lord Kelvin calculated that the age of the sun had to be in the range of millions of years, not thousands of millions. This required evolution to take place at a rate which seemed unlikely.

    Similarly, a geologist discovered evidence that the rocks of the earth were in many cases older than the limit on the earth’s age based upon the calculation involving the sun. In addition, the theory of continental drift was proposed to account for similarities in the shapes of the continents: these enormous land masses seemed to have shapes which could fit together like pieces of a puzzle, but the fit was not perfect, and once again the apparent age of the earth seemed to count against the theory. Another problem with this theory was that there existed no known engine for the hypothesised movement of the continents: as far as scientists of the time knew, the earth was essentially one giant, solid rock. Volcanos were simply a small, irrelevant side-issue.

    However, special relativity, which was originally put forward to account for experimental results involving the motion of light, required an equivilence between mass and energy which suggested that chemical fires were not that efficient. The study of subatomic particles lead to the recognition that nuclear fires could exist which would be much more efficient than chemical fires. Nuclear fusion made it possible for us to recognise that the sun is much older than we originally thought it was.

    Nuclear fission explained the generation of heat internal to the earth’s surface, and this made it possible for us to recognised the fact that the continents are afloat on a sea of molten rock which exists beneath the earth’s crust. This provided us with a means to explain continental drift. In addition, both botany and zoology discovered similar populations at just the places the theory of continental drift argued were where the continents had once been together.

    New evidence and once highly-controversial theories were fitting together like the continents once had. They were providing us with a unified view of our world. Whereas Karl Popper’s fallibilism viewed distinct theories as being tested against evidence independently of one-another, the history of science has shown a remarkable degree of interdependence between distinct theories existing in highly disparate areas of human knowledge.

    *

    With my last example, I will be considering Newtionian mechanics. If one stead-fastly held to Popper’s Principle of Falsifiability, one result contrary to prediction would be enough to falsify this theory. With this in mind, one could easily conclude that Newtonian mechanics has been falsified many thousands of times over in high school physics classes. Students perform experiments which quite regularly “falsify” this theory every year. But why is it that whereas this would be enough to discount the theory if the experiments were being performed by expert experimental physicists, this is not enough when the experiments are being performed by young students?

    When one explains this difference in terms of the different levels of training and reliability, one is bringing in psychological considerations to explain the results of physical experiments. Thus one can argue that there is a sense in which the science of physics depends upon the science of psychology.

    *

    I will draw from this analysis three conclusions.

    First, if one accepts induction, some element of coherentialism is required: there exists an interdependence between the justification of the distinct statements which compose a theory. Second, there exists an interdependence between the justification of a foreground theory and its background theories. Third, in science, one must regard many statements as true even if the justification of these statements does not admit of absolute certainty. Much of our knowledge is corrigible.

  188. CobblyWorlds:

    Marlo Lewis ?

    Hmmmm

    http://www.renewamerica.us/columns/mlewis/050929
    Marlo Lewis says:
    “The increasing frequency of hurricane activity in the Caribbean and Gulf of Mexico since 1995 is due to a natural, multidecadal shift in the Atlantic Ocean thermohaline circulation (THC), the oceanic “conveyor belt” that pulls warm water from the tropics northward to the British Isles.”
    THC or Gyre?
    Anyway he doesn’t mention Holland and Webster “Heightened tropical cyclone activity in the North Atlantic: natural variability or climate trend?”
    Pdf from the Royal Society here: http://www.pubs.royalsoc.ac.uk/media/philtrans_a/Holland%20and%20Webster%201.pdf
    Holland & Webster say:
    “42% of the observed 0.678C increase in hurricane season SSTs in the NATL
    since 1906 can be attributed with a high degree of confidence to anthropogenic
    gases introduced into the atmosphere.”
    Although the most interesting argument is in part 4 with respect to a possible natural role. Too involved for quote mining.

    Marlo Lewis says:
    “More important, global warming was not responsible for Katrina’s destructive fury. Any tropical storm traversing waters of 82 degrees Fahrenheit or warmer has the potential to become a category 4 or 5 hurricane. Gulf waters routinely exceed that temperature in August, and did so long before mankind began using fossil fuels.”

    Holland and Webster say:
    “Furthermore, equatorial developments increased sharply in 1995 in association
    with the marked increase in Atlantic SSTs since 1970, which Santer et al.
    (2006) have demonstrated to be largely due to greenhouse warming. Kossin &
    Vimont (in press) have related this to a warming phase of theAMM,which
    included the equatorward shift in formation and which they conclude could
    be influenced by greenhouse warming….
    ….The increase in equatorial developments places a substantially larger
    number of cyclones in a region that is conducive to sustained intensification,
    and this has been the dominant cause of both the trend in major hurricanes and
    the recent heightened activity.”

    Not a good one for me to pick – Hurricanes are not really my thing, but there’s not much science on that site as well (I’m just a hobbyist learning this stuff). As for the hurricane/AGW linkage – a promising hypothesis IMHO.

    On this page
    http://www.renewamerica.us/columns/mlewis/050408
    Lewis talks about CO2 not being a pollutant, and fertilization of crops, on those I don’t really know (don’t know if I care) – to me that’s not the point anyway. A tiger cub might be a benefit in controlling mice around your farm – but one day that cub will grow up and may take a liking to your livestock. Cost benefit analysis must consider timescales and the nature of the beast.

  189. dhogaza:

    But the basics of AGW theory do not rely on models: they’re just to get a better picture.

    Keith has been told this at least three times in this very thread.

    Keith – are you listening?

  190. Vera B:

    My understanding of this forum is that it is primarily for climatologists to educate the public and avoid disinformation. There are some good posts here, but as a newcomer to this forum (but not this debate) I must say the vitriol is a distraction. There may be contrarians posting under assumed names, but you have to take the high road. Assume all posts are legitimate. Posts links to earlier discussions for those of us late to this site. By all means keep posting links to peer reviewed articles. Quit demonizing skeptics – my mother is one. (OK, she watches Fox news – I can’t stop her!). Please remember that many people trust the news, not realizing that they must sell to stay in business – and controversy sells. You would make more converts by far answering every post calmly and logically. And repeatedly.

  191. David B. Benson:

    Anthony Hawes (171) — Click the Start Here link at the top of the page and read it. Then click the link to the AIP Discovery of Global Warming pages in the Science section of the sidebar.

    After reading these pages, you will likely agree that AGW is occurring.

    And in my inexpert opinion, it will be horrendously bad.

  192. dean_1230:

    RE 144

    Being asked to use averaged numbers rather than single dates, i went to the HadCRUT3 dataset and found the following:

    5 Year Central Moving Average:

    YEARSPAN : Delta T
    1910-1941: 0.5556
    1976-2004: 0.5938
    difference of 0.04°C
    % difference of 6.43%

    9 Year Central Moving Average
    YEARSPAN : Delta T
    1907-1941: 0.5524
    1971-2002: 0.6041
    difference of 0.0517°C
    % difference of 8.56%

    So all the uproar about the fastest rising ever is basically because of 0.05°C increase spread over more than 30 years. To claim that that is a significant difference is truly misleading. It’s not, especially when the variability/accuracy of the numbers are no greater than 5% to begin with.

    By the way, I went with a 9 year moving average because I wanted an equal number of years on either side of the center. Also, you ‘ll notice that I changed the years included to pick the highest and lowest points over these areas rather than a specific timeframe.

  193. dean_1230:

    Re #174 & #180

    The 0.55°C rise from the late 70s through today is accurate. But what is INACCURATE is the use of 1900 as the start date for the warming. The start date, depending on which averaging method you use, is around 1907-1911 and is as much as 0.15°C lower than the average at 1900.

    The difference between the highpoints and the lowpoints of the two warming episodes is almost identical (within 0.05°C). To say that 60% of the warming has happened in the last 30 years is clearly misleading. To infer that we’re warming faster over the last 30 years than we’ve ever warmed before is just as misleading. We are warming at the same rate as the early 20th century.

    [Response: actually, going with your 9-year running mean changes, it looks like the rate is 20% higher now (since the period of years is shorter - 31 vs 34 - in the recent larger change). - gavin]

  194. Chip Knappenberger:

    Re 181:

    Or, you all could have a look at the HadCRUT3v data here.

    -Chip

  195. dean_1230:

    Re 194 & 181

    Herein lies the rub… there is a significant difference between the two data packages (HadCRUT3 & GISS). If you use HadCRUT3, the temperature rise we’re currently undergoing is the same in magnitude as was seen in the early 20th century. IF you use GISS, it’s greater (by about 0.2°C)

    Since both of these are accepted temperature datasets, what does that say about our ability to accurately measure the global temperature?

  196. dean_1230:

    Re: the response to #193:

    But it’s still only 0.05°C, which is insignificant compared to the accuracy of the data. There’s more difference between which of the accepted data sets you use (GISS vs HadCRUT3) than the difference in warming if you use the HadCRUT3 dataset.

  197. John Mashey:

    re: #166 keith
    Keith says:
    “We’re absolutely nowhere in terms of applying physics to describe apparently simple chemical reactions. Ahmed Zewail has shown that even some of the most basic ideas we had were incorrect when applied to our most simple reactions so perhaps you can understand why I struggle to be comfortable with there being less experiments done in your field.

    I suspect that your view of the scientific method and mine are not the same as a result of the respective fields we work in but I agree that it would be instructive to look in more depth at your methodologies since clearly you generate, collect and interpret data differently. Perhaps you would be willing to do the same and consider how it differs outside of your own field? Maybe you could learn something yourself? You never know. Good luck with the research.”

    Now, that is a reasonable comment that may actually lead to fruitful discussions. As it happens, I’m fortunate to have at least talked to researchers in both domains over some years. [I used to visit big pharmas, who visualized molecules in conference rooms with 3D glasses ... of course, visualyzing molecules was the *easy* part.]

    Maybe Keith can suggest good references, but for now, Wikipedia suffices:
    http://en.wikipedia.org/wiki/Molecular_modelling
    http://en.wikipedia.org/wiki/Protein_folding

    Let me expand the discussion in #145 [about data, science, computing] by considering models, approximations, and usefulness.

    Many models (whether computer or otherwise) describe the real world, and act as approximations to it. People usually seek the highest-level (simplest) model that provides useful results, and historically, we generally got simplest ones first, discovered places where they didn’t work, and had to go deeper. The standard example is Newton -> Einstein -?> (unified theory)

    For instance, chemistry got a *long* way before quantum mechanics or computers, even without modeling the quantum chemistry at the next level underneath, or the quantum physics below that.

    On the other hand, in the domain Keith is talking about, for predictions to be useful, they essentially need to model very deep properties, and they have to give *exact* (in essence, digital) results, not averages (i.e., more like analog).

    For instance, this is easily seen in protein folding: see the first chart in the Wikipedia entry on Protein Folding.

    This is a nightmare: you start with a (relatively) simple linear chain of amino acids, i.e., something you can specify. This then “folds” into a particular physical shape (or can, under various circumstances one of several), and extremely important characteristics of the resulting shape matter. This takes many steps, but in general, under the same conditions, the same starting point will yield the same final result, which is a good thing for life on Earth.

    To be useful, a model of protein folding yields an *exact* result: a specific 3D configuration. If the model is really good, its result matches what happens in the real world. If the model is not quite good enough, it may mis-model one step of many in the folding process, in which case the result it predicts can be TOTALLY DIFFERENT, and in no way resemble what actually happens in the real world. The Wikipedia entry shows how incredibly far off they are from being able to do what they’d like.

    There is no equivalent of getting a prediction like:

    “Given XYZ assumptions, and known physics, we’d predict that the 5-year average in 2050 would be N degrees higher, +/- M.” That’s a bulk prediction with a distribution, and it’s a very useful prediction. It doesn’t mean that new data won’t modify it.

    At one extreme, some models predict:
    - bulk properties
    - distributions of results
    - are looking for approximations that are “good enough”
    - try to improve resolution over time

    For instance, climate science deals with an inherently noisy system, only expects to make predictions about averages across a few years, and for relatively large geographic areas.

    In the middle are models (like the cars, for example), that need to make detailed predictions to be useful, but:
    - more detailed approximations give better answers
    - there usually aren’t terrible discontinuities in the results, given small changes to inputs

    I.e., they don’t get results like:
    - If you do a headon crash at 5MPH, everybody is fine.
    - But at 6MPH, or at a 1degree angle off headon, the car blows up and eveyone dies. [Despite the Taurus example I mentioned earlier].

    In semiconductors, simulations of circuits and power are somewhat like this as well, or at least have been. They’re approximations.

    At the other extreme, a model, to be useful, must match reality essentially *perfectly* (at some level of abstraction), and even a small error somewhere can yield totally different results.

    In semiconductors, *logic* simulation is like that. Given a description of the logic, a logic simulator produces an exact answer [normally, pass/fail] for a given input. It *never* says “Passes this specific test at 95% confidence level”: if a chip designer saw that, they’d flee in terror.

    At least some of the modeling in Keith’s domain is like that.

    ====
    Anyway, that’s my quick (I’ve got to get ready for trip) take on it.

    Given where Keith’s coming from, I can sympathize with his concern …

    but really: many simulations of the real world (including climate)
    - small perturbations of inputs usually yield small perturbations of outputs
    - ensembles and sensitivity analyses can be useful
    - don’t need exact results, distributions are fine
    - error bars actually make sense

    and there are plenty of cases in molecular modeling where those aren’t true.

    So, does that make more sense?

  198. Svet:

    RE: Gavin’s response to #153
    “look at the maps. it is readily apparent where there are differences, and why. No mysteries there…. – gavin”

    Gavin, I assume that you are referring to the fact that the difference is in the Artic. Also, in another thread you have said. “There is a difference in how the[y] interpolate between data stations, particularly in the Arctic – HadCRU does not estimate Arctic ocean temperatures from nearby coastal data, while the GISS analysis does – given the warmth of the Arctic in recent years, that gives make the GISS anomalies slightly warmer.”

    Ok – there is no mystery but nonetheless I believe there is a problem. What GISS is doing is either valid or it is not. If it is valid then why has the Hadley Centre not corrected their methodology?

    Looking at it from another angle, the implication is that almost all of the warming in the last six years has been in the Artic. Is this what the models predict?

  199. Barton Paul Levenson:

    Keith writes:

    [[I simply have some doubts about the ability to predict the climate in 50 years with what I see as a limited data set.]]

    So does everybody else, since we can’t predict what emissions will be over that period. But given a predicted pattern of emissions, and assuming so many volcanoes go off, and so on, we can predict. Nobody has a crystal ball. Celestial mechanics comes closest, but even that has its limits.

    What this has to do with listening to the models when they tell us we’re in serious trouble escapes me.

  200. dean_1230:

    Re the response to 193:

    Gavin, how did you get 20%? The total difference in temperature between the two periods is 0.05°C.

    By the way, I calculated the percentage by taking the difference between the two temperature rises (0.04°C for the 5 yr average case) and dividing it by the temperature rise between 1976-2004 (0.5938°C) then multiplying by 100. That gave me 6.8% difference between the two warming periods. the 9 year average using the same method gave me 8.5%. So there’s a 2% difference solely due to which averaging technique you use.

    I also did a 5 & 10 year weighed average using the 5 & 10 previous years. The difference there was 3% for the 5 year case and 12% for the 10 year case. Clearly, when the choice of averaging technique used is generating larger deviations than what the actual difference is, any conclusions are inherently suspect.

    Can anyone claim that the data is so accurate that these differences and percentages are outside the error band of the data? If not, then there’s no statistically significant difference between these two warming periods.

    [Response: You said the rate of warming - that is the delta T divided by the time period. In the later period, you have a bigger delta T and a shorter time - that makes the rate faster (0.19 degC/dec vs. 0.16 degC/dec i.e. by 20%). But before this gets out of hand, remember that the only claim made in the original comment - which it should be said I did not originate - is that the warming in recent decades is more than half of the century long trend. It is, and robustly so, as Tamino demonstrates. - gavin]

  201. Barton Paul Levenson:

    Anthony Hawes writes:

    [[But hang on - we can’t even relably model climate days ahead (often not the carpark). ]]

    You have weather confused with climate. Weather becomes chaotic quickly and can’t be accurately predicted more than a week or two in advance at most. Climate is a global or regional average of weather over a period of 30 years or more, and is basically deterministic. An example to illustrate the difference: I don’t know what the temperature will be tomorrow in Cairo, Egypt (weather). I can be fairly sure that it will be hotter than in Stockholm, Sweden (climate).

  202. Mike Sigman:

    Given the NASA revelation in the last day or two that the Arctic warming is mainly a function of current variability, there are a lot of people with egg on their face at the moment. I’d like to ask the poster of #8 to think about the same question he posed for John Christy… what do you think about the Arctic melt now?

    [Response: Do you have a link? This is very unlikely to be true. - gavin]

  203. J.C.H.:

    http://www.foxnews.com/story/0,2933,311884,00.html

    [Response: Typical. You are better off reading the real paper and press release. In them you will find no information about the ice changes - this study is purely concerned with ocean circulation differences - which do indeed have a strong decadal variability. The trend in sea ice however, does not. - gavin]

  204. Anthony Hawes:

    There have been two posts (176. and 201.) criticising me regarding the difference between weather and climate – I understand fully the difference between the two. My point is that the level of complexity in weather is actually LESS THAN the level of complexity in the climate models, and furthermore our understanding of weather systems is BETTER THAN our understanding of the climate system. The argument is like that of economic modellers: that is, the day to day variability of the stock market is just noise, its the long term trends that are important – PROBLEM, the long term trends CANNOT be modelled. And I am sure (hope) the climate scientists here agree that climate is vastly more complex than the stock market. Any way – I hate analogies.

    By the way, it is a typical reaction that I get when I want to know more about the data link I posted (http://hadobs.metoffice.com/hadat/images.html) – attack the man not the data (especially post 176.). The last 5 years certainly don’t support the projections from the models.

  205. Hank Roberts:

    > certainly don’t support

    Have you informed the people there what you’re asserting based on those images? They ask you to let them “know when you use them and for what purposes” — they might even drop by and say whether they agree with your interpretation.

  206. John Mashey:

    re: #204 Anthony
    The climate is constrained by the laws of physics, unlike the stock market, which occasionally at least breaks the law of gravity.

    You apparently don’t believe in laws of physics, or you think the economists have similar laws.

    Due to some modest operations research background, I was one of the people at SGI pushing (successfully, for a while, anyway) into economic modeling, Wall Street modelers, etc.

    I used to talk to them, just as I talked to climate modelers AND weather modelers.

    My experience does not accord with what you say, but maybe you have some relevant experience. If so, since you make strong statements, rather than asking questions, perhaps you can explain the basis for your assertions. I understood the domain difference between Keith’s and climate scientists’ models, but I don’t understand why you’re saying what you’re saying.

  207. J.C.H.:

    “- PROBLEM, the long term trends CANNOT be modelled. …” – Anthony Hawes

    What are some examples of things you think are not understood about the climate system that would prevent climate models from making accurate predictions of long-term trends?

  208. Raplh Smythe:

    Very interesting. Going from .03% of the atmosphere to .04% of the atmosphere, a trace gas that’s part of an incredibly complex, not totally well understood system, yanking it out because it looks correlated to the .7 C upward temperature anomaly trend and then attributing a cause/effect relationship to that. What about the IPCC’s land usage part of this, seems rather convenient to ignore it. Or the particulate aspect of fossil fuel usage. Even more odd is the fact that for the last 400K years the temperature has had +2 -8 C swings and oxygen18, sulfur, temperature, carbon dioxide and solar strength all move at once.

    Other than models that make assumptions, is there any other evidence that there is a cause/effect relationship between two of the variables in the system? That putting .01% more carbon dioxide into the atmosphere makes the asymmetric stretching and bending vibrational mode behaviors of it create a net .7 degrees of heat on a trend over a century+ (ignoring any lag) after removing everything else from the equation?

    Yes, I’m familiar with what ModelE says, but what else supports that? Please don’t mention melting ice or receding glaciers visually confirming it, that can be explained by particulates and ocean current and wind and the increased temperatures, just as particulates moderate the effects of other GHG and the weather patterns of the system. There seems to be a lot we don’t know in this equation, and it seems to jump to conclusions. Is making this conclusion now simply because it’s the best information we have, and we know how carbon dioxide acts well, and any explanation is better than none?

  209. Hank Roberts:

    Raplh, are you the same person who posted this?
    http://www.realclimate.org/?comments_popup=473#comment-56083

  210. David B. Benson:

    Raplh Smythe (208) — Click on the link at the top of the page labeled Start Here. I also recommend the pages in the AIP Discovery of Global Warming site. The link is in the Science section of the sidebar.

    Reading these will anwer many of your questions.

  211. dean:

    Re the response to 200:

    But to put the current rate in perspective, to say that that rate is well beyond what Nature can do herself is disingenuous. It most assuredly is not as can be clearly shown by looking at the data from 1910-1941. You must assuredly realize that the difference between the two rates over 100 years is a measly 0.3C (which I still maintain is statistically insignificant especially given the discrepancies between the GISS & HadCRUT3 datasets).

    Simply put, HadCRUT3 does not support the conclusion that the rate of rise in the current temperature data is greater than that which nature has done in the past.

  212. Steve Bloom:

    Re #s 202/3: Gavin, I nailed Timo on this little misinterpretation back up in #154. With only a couple hundred comments in this thread so far, *surely* you didn’t forget? :)

    Note to Mike Sigman (#202): There are a fair number of people out there, Timo e.g., who have made a cottage industry out of misinterpreting climate science papers from a denialist POV. Such people frequently make claims about this or that important aspect of the science being challenged by the paper, but that pretty much always turns out not to be the case. More rarely you’ll get a scientist making a similar claim about their own paper, but generally they too turn out to be wrong (see e.g. the Stanhill paper discussed in the next thread). So if in future you see such a claim floating around out there, by all means feel free to ask about it, but try to ask rather than tell.

  213. David donovan:

    Chris K and Dean

    It looks like what you are doing is determining the slope of a noisy signal by simply picking an somewhat arbitrary `low point’ and pairing that with a `high point’. This is not considered good practice even in 1st year physics labs ! IMHO your claims seem very silly.

  214. Raplh Smythe:

    Hank, yes. The other post was about China mostly (and policy decisions involving them and others). Have I said anything that’s demonstratably incorrect? If so I will adjust. I believe that unless we can get both China and India to get on board, anything else is rather too little. Perhaps I’m just more pessimistic than I should be. I also think that it doesn’t matter what the details are; alternative fuels are good things if they don’t have unintended consequences. I think that’s where we should spend our time and energy rather than argue about proving an average of less than 1 ppmv per year causes less than .01 degree per year rise. Regardless of the relationship. And who isn’t for clean air and clean water?

    David, think as if you are grand poobah in charge of environmental policy for the US. You’re aware that the CO2 levels went from .03% to .04% and massive changes to our environment on the ground have been made, and that particulates in the air are cooling and on the ground are warming, and it’s been 125 years to get from there to here. You know that methane contributes, and that there’s some sort of cycle going on involving all these things interacting with clouds and water vapor and the heat/CO2 content of the oceans. You know the global mean anomaly has gone up .7 C over that time as a composite of land and sea sampling over time. You know that in the past, the variation’s been as big as 10 degrees and that the 5 major indicators all follow. In addition, most of the information is from models using assumptions about some of the more poorly understood variables in the system.

    Instead of getting something like that, they are told “CO2 levels are up 33% since the start of the industrial era and there is dangerous warming going on, and it’s accelerating.”

    Overstating the case is, I think, counterproductive. And how many pages long is AR4? I just think the focus is on the wrong things.

  215. Raplh Smythe:

    BTW, I totally agree with gavin in the comment in #1: We know the models are imperfect, but unless we can define what it is we’re talking about, making blanket statements about the worth (or lack thereof) about the model is meaningless. We have to be more specific about what the issue is, and how it’s taken into account or not. Vague generalizations are meaningless, and the idea that we can throw out the model just because we don’t understand the function of x very well is disingenious to say the least.

  216. Ray Ladbury:

    Ralph Smythe, That is the most astonishing mish-mash of misinformation (disinformation?) I’ve seen in awhile. Do you think that by throwing out words like “particulates” and mentioning a few random elements–all with no context–that you can gain some credibility here? Guess you were wrong. Look, if you want to learn about the science, you came to the right place, but try to figure out what it is that you don’t understand and ask questions. Don’t try to fool experts by blabbering CSI-style gibberish.

  217. James:

    Re #204: [The argument is like that of economic modellers: that is, the day to day variability of the stock market is just noise, its the long term trends that are important - PROBLEM, the long term trends CANNOT be modelled.]

    Nonsense! I can give you a workable model of the stock market “climate” in one sentence: “In the long run, the stock market will increase in value about 7% per year, after inflation”. I could even give you a fairly amateurish explanation of why, if I felt like typing a few paragraphs.

  218. Ray Ladbury:

    Keith, Twenty years ago, James Hansen predicted 20 years of warming. The subsequent 20 years have included the 13 warmest years in the past 125 years or so. That was a prediction. The probability of it occurring by chance is infinitesimal. The Mt. Pinatubo eruption was put into the models–no tweaking of parameters, no data fitting–and the models nailed it.
    Look, I work on radiation effects in semiconductors. When I test a 1 Gbit DRAM (as I just did), I am looking at only a few of the millions of state vectors in the state machine. If I wanted to test all of them, I would be testing for 15 years. I have to use modeling. Do I validate my results? You bet yer ass. But climate models are being validated continually.
    And in any case, the reality of anthropogenic climate change depends in no way on the models. All the models do is tell us the sensitivity will likely be 3 K per doubling and not 10 K per doubling. They are the only way we have to limit our estimate of the risk we face.
    Science works, Keith, and it works in more than just chemistry and physics. The scientific method can be applied in ways and to problems Galileo and Francis Bacon never dreamed of. Maybe you should learn how it works.

  219. Ray Ladbury:

    Anthony Hawes said “PROBLEM, the long term trends CANNOT be modelled.”

    Gee, tell that to Warren Buffett–or hell to anybody who has been investing in their 401K. Anthony, the key to investing is not to look at the day-to-day variations (the weather), but rather at the average trends. And these CAN BE predicted and modeled. Can I tell you the temperature on Jan. 1, 2100. Of course not. Can I tell you that it is likely to be warmer than on Jan. 1, 2000. Yup! You are projecting your own ignorance onto the rest of the world–and climate scientists do not share it.

  220. Wayne Davidson:

    #203 Fox news…. Really ? They have news????

    #208…

    .04% hey? How about ozone? Knock all of .01% of it and what happens?

  221. John N-G:

    #218 “The probability of [Hansen's prediction verifying] by chance is infinitesimal.” Infinitesimal only if you assume annual global temperatures are white noise rather than red. I suspect the chances of a substantial 20-year warming trend at that point were somewhere around 1 in 10. Not infinitesimal, but still impressive. Someone with more time than I (Tamino?) should do the math.

    #179 I believe the “John” was John Mashey.

    [Response: John--actually this raises a number of interesting, and non-trivial considerations. If one uses the raw lag-one autocorrelation coefficient of the global mean surface temperature series (for hadcrut3 global mean 1850-2006, rho=0.87) one gets a decorrelation (e-folding) timescale of about 8 years, and a natural 20-year warming trend can arise quite readily given the red noise null hypothesis. However, the estimate of rho is arguably greatly inflated by the presence of long-term trends that are anthropogenically forced. In fact, if one compares the spectrum of global or hemispheric mean temperature with the spectrum of the best-fit AR(1) process, one finds that the low-frequency variability is far to great to be explained by an AR(1) null hypothesis. One way around this is to use a robust approach to fitting the AR(1) spectrum to the spectrum of the actual series. This yields a far smaller decorrelation timescales of about 1 year (see e.g. Mann and Lees, 1996), making a 20 year warming trend far more unlikely under the red noise null hypothesis. Yet another approach would be to use a coupled model forced by natural radiative forcing changes alone. Using a simulation of the NCAR CSM 1.4 coupled model forced by natural solar and volcanic radiative forcing (Ammann et al, 2006) over AD 850-1800, I get rho=0.6 (varies somewhat for any given 150 year period), which leads to an estimate of tau = 2 years, making a natural 20 year warming trend again unlikely. Someone w/ more time on their hands could calculate the probability distribution of 20 year warming trends based on the above alternative estimates of the noise decorrelation timescale. - mike]

  222. Laphroig:

    Barton, Re 201

    This issue of weather/climate gets a bit irksome. My difficulty is that we simple do NOT have any direct experience of climate, what we actually, and only, experience is weather, and we do that in the eternal “now” of consciousness. Weather is “real”, climate is an abstraction, based on memory (terribly spotty, and often downright creative). Of course we add various systems that attempt to augment memory by inserting some sort of “objective” devices (thermometers) or systems (record keeping and adjustments) to counter the pure subjectivity of sense experience. And those abstractions are far simpler than the reality of the experience of weather. They basically consist of temp, wind and humidity. What about all the little variables like, how old you are, what you’re doing, and with whom, when you last ate, what you drank the night before, what you’re wearing etc. If it gets a little warm, it’s also a whole easier to adjust a few of these than, say, change the climate.

    Now, as a set up for a question, a few months ago we (family members) performed a little experiment. At a point on the highway 2 about 15-20 minutes from the southern outskirts of Edmonton we had friends park at the side of the road to wait till they received our phone call when we got about 10 blocks into city. When we separated both of our car outside temperature readings were the same. When we phoned them our temp reading was four degrees warmer, whereas theirs remained constant. So direct experience tells me that within about 20 miles (on basically flat prairie, and with no obvious weather changes), there was a significant change in temperature between two close points in the same time.

    Discounting the UHI issue here is my question. In an anything-is-possible world what size would the grids have to be so that the earth’s temperature would be based on the whole earth, i.e. that the temperature in any one grid would vary no more than, say a degree from its adjacent grids? If memory serves (and that’s a stretch) a really accurate survey could probably be made with a sample of 12 to 15 hundred, but would also require that each of these world wide grids would have an equal chance of selection and all would be selected by chance.

    Then to get over the quibbling about things like min/max etc., maybe we do this on an hourly basis, changing half the sample each hour, for a year or so ( a sort of tempersherry—eecchhh!).

    Now I realize that this way of monitoring of the earth’s real temperature may be a bit gold platted, but on a scale of 1 to 10 (10 being this one) what score would you give to those that are being used today?

    Thank you.

  223. Ellis:

    172
    CW-Gavin was clearly not engaging in a Straw-Man argument.
    Hothouse – Snowball is the natural range of the Pharenozoic. In order to support your argument you must specify what bounds of natural variability you are referring to. So as you seem not to prefer the bounding Gavin points out, perhaps you could define what you see as “the bounds of natural variability”.

    First, Gavins’ bounds of natural variability is not the straw man. His, “your argument is equivalent to saying that nothing less dramatic than the freezing over of the oceans or the raising of the temperature by 10 deg C or so can possibly be attributed to any forcing.” is a perfectly constructed straw man, completed with the conclusion that my point is absurd. I am not even sure if it is possible to disprove natural variability with extremes of natural variability, but, if it will make you feel better when I wrote the comment I was refering to the Holocene.

    CW- You state (with respect to orbital forcings, giant volcanoes, asteroids, Heinrich events etc) that: “I am not sure that it follows that none of them are relevent today.” If you are not sure then it implies that you have reason, thus you should be able to detail such reason in terms of mechanism and evidence…
    In other words – please do so.

    I am not sure that it follows is a nice way of saying you are wrong. The rest of what I wrote, “Our climate is defined by the orbital forcings, however, I understand your point that these forcings change little on centennial time scales.” I believe makes clear that I was able to infer Gavins’ meaning. For further reading about the mechanics that are the overriding facets of the climate system please see http://en.wikipedia.org/wiki/Milankovitch_cycles.

    CW-You state: “The theory of AGW rests only on one principle, as far as I can tell, that the warmth of the past century is outside the bounds of natural variability.”
    AGW clearly does not rely upon the current warming being outside the bounds of Holocene variance.

    Technically, you are correct AGW can exsist within the boundries of Holocene variability. However, as you state, “What matters is whether atmospheric CO2 levels can be driven high enough to attain that state in the future.” Thus, eclipsing natural variability, and if you really believe that the argument for AGW is not being driven by the departure from the normal, then I humbly suggest that you are not following the story.

    CW-Then you take Gavin’s clear analogy and attempt to dismiss by taking it literally. Which whilst worth noting is unworthy of comment.

    “Just because large forest fires have occurred naturally in the past, does that imply that arson cannot happen?” Is not an analogy, it is a non sequitur, and my sarcasm is an appropriate response. Perhaps you were refering to the next line from Gavin,” Or that if we see someone walking away from a fire with an empty kerosene can and some matches, we can’t logically infer that he may have had something to do with it?”
    To which I responded, “I don’t object to the claim that a dissproved alternate theories bolsters your stance, I do object when this is taken as proof of your theory.”
    Is this not reasonable?

    CW-You state,”We have warming, backed up not only by a range of different measuring techniques – from boreholes to satellite thermal emission from the atmosphere, but also by the global average trend in water vapour changes. The increase in ocean heat content shows that the warming is significant.”

    Now it is your turn, please direct me to water vapor trends and ocean temperature trends. Also, the expression we have warming is meaningless without a starting point, for the holocene we are actually cooling.

    CW-We have concomitant observations that are expected with CO2 (diurnal range, vertical profile of changes – stratospheric cooling, tropospheric warming).

    Is the stratosphere cooling because of CO2? This graph shows very strong correlation between observed cooling and total ozone.
    http://www.giss.nasa.gov/research/features/tango/ozone_temperature_graph.gif
    Perhaps, you could direct me to the graph of stratospheric CO2 content versus observed temperatures and we can compare and contrast?

    CW-To dismiss CO2 you have to address this pattern. If CO2 isn’t to blame, what is causing the warming and the observations I outline? The stance “It must be anything but CO2″ does not constitute a theory.

    Excellent, now you can set up a straw man just like a bona fide climate scientists.

  224. Roger Coppock:

    Why do fossil fools tell obvious lies? The strategy is to provide
    static. You’ll see the same strategy from the local baseball fans
    when the opposing team is at bat. Constant senseless banter
    prevents an opponent from concentrating. “Hay batter, hay batter,
    batter, batter, SWING,” replaced by, “Mediaeval warm period,
    cooling since 1998, computer models . . .”

    Note that these lies live in their own underworld. You don’t see
    the fossil fuel industry using them to defend themselves from
    environmental lawsuits. You won’t see these obvious lies from
    US major party presidential candidates, regardless of how much
    money the industry has contributed to their election campaigns.
    In both venues, facts are carefully checked and there are
    penalties for telling obvious lies.

  225. Jim Eager:

    Re Anthony Hawes @ 204: “There have been two posts (176. and 201.) criticising me regarding the difference between weather and climate – I understand fully the difference between the two.”

    Yet you still wrote “we can’t even relably model climate days ahead,” a favorite rhetorical throw-away of AGW “skeptics” and outright denialists.

    Why?

  226. Barton Paul Levenson:

    Ralph Smythe writes:

    [[Going from .03% of the atmosphere to .04% of the atmosphere, a trace gas that’s part of an incredibly complex, not totally well understood system, yanking it out because it looks correlated to the .7 C upward temperature anomaly trend and then attributing a cause/effect relationship to that.]]

    You are misunderstanding something fairly basic here. The greenhouse effect does not depend on an observed correlation. It is a matter of radiation physics. If you put more of a greenhouse gas in a planet’s surface, then the surface must become hotter, unless some countervailing process is blocking it. The theory of global warming depends on radiation physics, not on observations of climate.

  227. dean:

    Re: 213

    David, actually I did as I was asked to do by Marcus (see #144), namely do a 5 and 10 year average of the data rather than a single point. I did not just take a low and high point and run with it.

    I looked at the results and I just came to a completely different conclusion than the rest of this community. Namely, than when using the HadCRUT3 data, the temperature change we’re seeing isn’t outside the natural variation as had been claimed.

    Instead of just saying i don’t know what i’m doing, why not look at the numbers I’ve posted and figure out how i’m misinterpreting things. In doing so, I challenge you to explain how the differences between datasets is immaterial when delta between datasets is significantly larger than the delta I’ve documented.

  228. John N-G:

    #221 Mike, thanks for the detailed response. “…raises a number of interesting, and non-trivial considerations” Does it ever, and I did not acknowledge that complexity in my first comment.

    Your answer is colored by a signal detection background, while mine is colored by experience with forecast verification.

    First off, we must define the a priori knowledge and a “no-skill” forecast. If the “robust” estimate of the red-noise spectrum is used, the success of the forecast is no more than a demonstration that low frequency and/or secular signals are present, i.e. signal detection. But the successful Hansen forecast is intended to stand for something much stronger: that the significant very low frequency and quasi-secular signals are predictable (using a physical model with appropriate forcings). In that context, the forecast must be verified against the assumption that the very low frequency and quasi-secular signals are unpredictable, that is, part of the red noise spectrum. Thus it seems to me that the raw lag-one autocorrelation is more appropriate here for determining the skillfulness of the forecast.

    (There’s probably a good journal article to be written about this, if you want to discuss it offline.)

    [Response: Sure thing John, would be very happy to discuss this further offline :) - mike]

  229. Hank Roberts:

    Google: hadcrut3 stoat

    William has posted several times about taking averages from this data set; the CA folks have been arguing about his postings a lot lately.
    That may be spilling over into this thread, just guessing.

    This thread from Nature may help (albeit it’s well seasoned with, um, various uniquely personal theories in the comments).
    http://blogs.nature.com/climatefeedback/2007/09/some_climate_change_fallacies.html

  230. Jim Eager:

    Re Raplh Smythe@ 2008: “Very interesting. Going from .03% of the atmosphere to .04% of the atmosphere, a trace gas that’s part of an incredibly complex, not totally well understood system, yanking it out because it looks correlated to the .7 C upward temperature anomaly trend and then attributing a cause/effect relationship to that.”

    What’s interesting is that you choose to describe atmospheric CO2 as a mere “trace gas” comprising only .03% to .04% of the total atmosphere, a favoured rhetorical tactic employed by “skeptics” and out right denialists in an attempt to minimise the role of CO2 specifically and of greenhouse gasses in general.

    By this measure water vapor, which varies as a proportion of the atmosphere depending on temperature and altitude, comprises a high of around 4%. Methane (CH4), the third most common greenhouse gas, constitutes a miniscule .00017% of the atmosphere, while nitrous oxide (N2O) stands at .00003%. Man-made chloroflourocarbons (CFCs) and a host of other trace gases comprise slightly less at around .000025%, and ozone (O3) is even smaller at .000004%. In other words, all greenhouse gases combined comprise only 4.040229% of the atmosphere.

    Yet these gasses are responsible for warming Earth’s surface and lowest portion of the atmosphere by around 33°C, which is clearly all out of proportion to their percentage of the atmosphere. It’s therefore far more instructive to describe CO2 in terms of the greenhouse effect it accounts for and how important its increase is, as opposed to its percentage of the total atmosphere.

    H2O makes up the largest portion of total greenhouses gasses by far, accounting for between 36% and 66%* of the greenhouse effect, but It can only increase in the atmosphere as temperature increases–any excess simply precipitates out as rain, snow or ice within days.

    CO2 is second, accounting for between 9% and 26%* of the greenhouse effect. it is relatively long-lived in the atmosphere (50-200 years or more), and since 1750 (the pre-industrial era) atmospheric CO2 has increased by nearly 38% and is still rising rapidly, almost entirely due to anthropogenic causes (burning of fossil carbon fuels, cement production, land use changes), slowing of natural carbon sinks as they approach saturation, and emission from frozen soils as they thaw.

    CH4 is third, accounting for 4-9% of the greenhouse effect. Methane, which is ~21 times as powerful a greenhouse gas as CO2, is relatively short-lived in the atmosphere (~12 years), yet it has increased by 152% since 1750, also mostly due to anthropogenic causes (agriculture, animal husbandry, coal, oil and gas extraction), plus, it breaks down into CO2 in the atmosphere, so its carbon continues to be part of a greenhouse gas.

    O3 accounts for 3-7%. Tropospheric O3 has increased due to anthropogenic emissions, but stratospheric O3 has decreased due to CFCs and HCFCs.

    N2O only accounts for around 1.3-3%, but it is ~310 time more powerful than CO2 and relatively long lived (120 years). It has risen by 18% since 1750.

    CFCs, which did not exist before mid-C20, are an entirely new addition. They are 5000 to 14000 time more powerful than CO2. Fortunately they really are trace gasses.

    *The reason for the large range is the overlap in wavelenghts that H2O and CO2 absorb.

    So, the next time someone tries to assert that CO2 is only a harmless “trace” gas, keep all this in mind.

  231. David B. Benson:

    Raplh Smythe (214) — As there are several Davids here, I don’t know whether your remark was directed to me or not. Since you fairly clearly didn’t do the assigned reading, :-) I’ll respond just to

    Instead of getting something like that, they are told “CO2 levels are up 33% since the start of the industrial era and there is dangerous warming going on, and it’s accelerating.”

    CO2 is now 385 ppm, was 280 ppm, so I hope the correct ratio, 1.375, is communicated. This results in a radiative forcing of about 1.5 W/m^2 and it is dangerous, particularly to marine organisms. It is accelerating in that the CO2 concentration now goes up about 2 ppm per year, as opposed to about 1 ppm per year in the 1990s.

    To illustrate the magnitude of just the CO2 problem, about half of the total radiative forcing, it is estimated that humans have added about 500 billion tonnes (Gt) of carbon to the active carbon cycle by burning fossil fuels and net deforestration. Bringing the radiative forcing due to CO2 down to the level experienced in 1950 (1/2 of today’s) requires permanently sequestering about 350 Gt as well as eliminating or sequestering the yearly addition of about 8.4 Gt. If accomplished, the net radiative forcing would be about 3/4 of the current value, still substantial.

  232. CobblyWorlds:

    “if you really believe that the argument for AGW is not being driven by the departure from the normal, then I humbly suggest that you are not following the story.”
    Of course we’ll leave the bounds of Holocene variability, just give us a chance. We’ve only got round to using under 10% of the extractable reserves of fossil fuels. And we have a warming commitment for what we’ve done so far. That said I’m glad we at least now agree that whether things are out of natural variability (specifically holocene) is not critical to the science. And with regards the “story” – I just read the science.

    Milankovitch cycles.
    These are demonstrably not causing the current warming. Sorry, I use that wiki page as an aide memoire – no news for me there.
    The actual changes in forcing (typically given at 65degNorth) due to precessional components are small and happen way too slow e.g. Roe “Indefence of Milankovitch” pdf http://earthweb.ess.washington.edu/roe/Publications/Roe_Milankovitch_GRL06.pdf – note figure 2. The actual lattitudinal insolation changes are amplified by changes such as ice sheet response causing albedo change as a positive feedback.
    In Hansen et al “Trace Gasses and climate Change” figure 3 demonstrates that you need to include GHGs to get close to the temperature variations observed in the ice-ages. http://pubs.giss.nasa.gov/docs/2007/2007_Hansen_etal_2.pdf

    Non-sequitur?
    “Just because large forest fires have occurred naturally in the past, does that imply that arson cannot happen?” – Gavin
    Could be translated as:
    Just because natural factors have caused changes in the past, that does not mean that the changes we see today cannot be due to humans.
    Surely you don’t think that’s a non-sequitur?

    Temperature trends etc.
    I’m so tempted to refer you to google (I’ve been used as a contrarist fact-gopher before). ;)
    But as you ask so nicely:
    Oceans – I recomend the Levitus et al study of ocean temperatures and heat content – Warming of the World Ocean, 1955-2003. Available from the 2005 collection on this page: http://www.nodc.noaa.gov/OC5/indpub.html
    Humidity – only got a paper version – Met Office UK work has shown little/no(?) change in relative humidity but an increase in specific humidity. The point is that’s an expected signature of warming. i.e. it really is warming.
    3 main surface datasets. See my post 82 above for graphs.
    And here from the Met Office is the LoStrato/Tropo/Surface compared: http://hadobs.metoffice.com/hadat/images/update_images/global_upper_air.png

    Statospheric ozone.
    The graph you linked to is from this page: http://www.giss.nasa.gov/research/features/tango/
    The legend for that graph clearly states it is for the Arctic.
    Ozone levels are higher at the poles: http://www.ccpo.odu.edu/SEES/ozone/class/Chap_1/index.htm (4.2 Distribution of Ozone by Season and Location) Because there’s more ozone in the Arctic than at lower latitudes it does not surprise me that there’s a close correlation between it’s loss rate and temperature. But on this page: http://www.gfdl.noaa.gov/aboutus/milestones/ozone.html you’ll see a study of the contribution of O3 and greenhouse effect cooling by GFDL.
    The mesosphere is cooling – ozone is not a significant factor there. But a reduction in outgoing longwave flux due to the enhanced greenhouse effect can cause such a cooling. There’s a plain-english rundown here: http://www.wunderground.com/education/strato_cooling.asp
    So yes, there is a contribution from O3, but the greenhouse effect also has a substantial contribution. By the way, CO2 doesn’t have an impact on the stratospheric trends by virtue of it’s presence in the Stratosphere. Most of the enhanced greenhouse effect is seen within the low-mid troposphere. Strato cooling by ozone is due to reduced absorption of UV with less ozone. Strato cooling by GHGs is due to a reduction in the net upwards flux of IR. Increased solar radiation would imply a warming of all levels of the atmosphere.

    And finally, to dimiss CO2 you really DO have to address the phenomena it explains, I am not being difficult here. It’s impossible to prove absolutely that a theory is correct. The work in considering a theory hangs upon attempts to refute it – stacks of that has been done in primary peer-reviewed science – and the theory of the enhanced greenhouse effect is stronger for it.

  233. Keith:

    John Mashey.

    Thank you, thank you, thank you. I have just that light bulb moment where for the first time somebody has actually give me an explanation that makes sense rather than just shouting at the top of their voices. Yes, John, that’s exactly right, we do need what is in effect a binary result. Your explanation of why climate models are in less need of such definitive, absolute results makes things much clearer. I can see how over time a model might evolve but still give the same overall result. I won’t say that I understand fully why that is; I’d need to do a lot more reading round the subject, but it makes sense. Perhaps it’s the difference between accuracy and precision. Anyway, thank you. I have a MUCH better feel to what is being discussed and why the fields are more different than I’d imagined. Superb. A great explanation. Thanks mate!

  234. Theo H:

    I’m a real layman when it comes to all this on computer modeling.

    OK, so a _very_ simple question. If computer modeling is not to be the way future climate is to be predicted, what is/are the alternatives?

    Theo Hopkins.

    (Or should the UK’s Met Office Chief Scientist, who lives just round the corner from me, tap on the glass of a barometer as he settles at his desk each morning?)

  235. David B. Benson:

    My comment #231 — Oops! Wrong arithmetic. Removing that much carbon from the active carbon cycle gets the CO2 radiative forcing down to about 1/3 of today’s value, for a total radiative forcing of about 2/3 of today’s value.

    Theo H (234) — Why not use computer modeling to predict future climate?

  236. gringo:

    Among the many vague “cooling is coming” statements I found on the Net there is this:
    ” I still think, personally, that once the ocean’s deep water currents change, that we will see a cold trend, (after the heat up).”

    I’m not a scientist and I don’t know anything about the link between global mean temperature and ocean currents. What do you think this guy was talking about?
    Does the IPCC take this possibility into account or this is just more BS from contrarians?

  237. Ray Ladbury:

    Gringo, Well… first, I’d like to ask why your correspondent thinks the deep-water currents will change…and why it is more likely that the change will increase cooling, rather than warming. I know of no reason to expect either. The whole thing sounds like a Cubs fan saying “Wait ’til next year…”
    It is true that the deep oceans represent a huge heat reservoir, and if you started having a large amount of overturn of cold water to the surface, it could cool things off for awhile. However, what happens when the warm surface water starts warming the deep oceans? You might start getting clathrates sublimating, increasing methane in the atmosphere, and that would warm things up again really fast. Your correspondent would seem to be involved in the time-honored activity we call wishful thinking.

  238. gringo:

    Ray,

    As it usually happens, he didn’t explain why he thinks what he thinks. But isn’t this view similar to that of William Gray?
    And since 2006 was just the sixth warmest year on record and 2007 will also be cooler than several previous years ( I guess due to La Nina as the Jan-Apr period was warmest on record according to NOAA) don’t you think the contrarians will use this as evidence that some natural factor now overwhelms GHG forcing?

  239. Concerned of Berkeley:

    Have you guys addressed this paper yet?

    “Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
    Version 3.0 (September 9, 2007)” by
    Gerhard Gerlich and Ralf D. Tscheuschner

    http://www.arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v3.pdf

    [Response: Some links here: http://www.realclimate.org/wiki/index.php?title=G._Gerlich_and_R._D._Tscheuschner - It's garbage. - gavin]

  240. Chuck Booth:

    Re # 222 Laphroig: “we actually, and only, experience is weather, and we do that in the eternal “now” of consciousness. Weather is “real”, climate is an abstraction, based on memory (terribly spotty, and often downright creative).”

    By that logic, anything that happened more than a fraction of second ago, such as our “experience” with this morning’s weather, is based on memory (terribly spotty, and often downright creative). Fortunately, people have been keeping detailed records of temperature, humidity, barometric pressure, rainfall, the times of germination and flowering of plants, the geographical distribution of plants and animals, the departure and return of migrating birds, etc, at many locations for a long time, in some cases for centuries. Plus, there are slow-growing animals and plants whose tissues record average growth conditions at fixed locations over decades or centuries; together with modern weather recording networks on land, in the ocean, and in the atmosphere, these data allow climatalogists to generate detailed records of climate at diverse geographical locations on the planet, and to account for geographical variations, such as urban heat islands, when estimating mean values for a region or the entire globe.

  241. Rod B:

    Gavin, re your response to 203: What did the NASA press release mean, then, by “…The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.” ?

    [Response: Exactly what it says. The ocean circulation changes have a significant decadal variability, but the sea ice shows a much stronger trend that is likely tied to GW. - gavin]

  242. Lawrence Coleman:

    If you were watching An Inconveneint truth al Gore mentions that in eons past the great lakes are remmenants of a huge inland fresh water sea that broke the banks on the Nova Scotia side of Canada, trillions of gallons of fresh water was released into the ocean, effectively stopping the Great ocean conveyor, this had the effect of plunging huge parts of the nothern hemisphere into a snap ice age that lasted a thousand years or more. The area east of nova scotia is where the sea is saltier and thus more dense and begins sinking and moving south at the bottom of the atlantic whilst the less salty ocean currents run over the top heading north just west of ireland. When this massive flood of fresh water diluted the saltier water about to head south it jammed the conveyor and in as little as ten or so years europe and north america was plunged deeply into a severe ice age. Now what do expect happens when the increasing ice melt from greenland enters the ocean?? No-one knows! It could trigger the conveyor to slowdown or stop completely. My guess is that it wont stop since the ice melt is happing at a slower pace than the sudden surge from americas great lakes region.

  243. Lawrence Coleman:

    f you took measurments many thousands of years back you will see cyclical changes in the ice shhet thickness and area, but are small ripples when you compare them with the disturbng trend seen now… a 23% reduction in area in two short years. We are no in a situation where positive feedback loops are heterdyning on other positive feedback loops causing dramatic instability.

  244. Hank Roberts:

    > he didn’t explain why he thinks what he thinks

    I searched out the one page where you found that belief about ocean currents. I’d suggest starting somewhere else.*

    “Start Here” link at top of page; Science links in right side.

    ________
    * Remember, this is the Web, not Usenet (“the way to get good information on the Usenet is to post what you think and await correction”). On the Web, anybody and everybody’s got more opinions than you can shake a stick at, and few people try to teach.

  245. Lawrence Coleman:

    But to be a devils advocate to my own question over whether the ice melt from greenland will cause the ocean conveyor to change it’s ways is this point; With less and less ice covering the north polar region the sea gets warmer and less dense..so the ocean current coming north past the west coast of europe and ireland will have less cooling thus less salt concentration and thus less sinking…so the ocean conveyor could well stop altogether but over decades I think, not suddenly. What will probably happen soon if it’s not happening already is that the speed of the conveyor will gradually slow down…so one major canary in a coalmine..will be if we see an accelleration in the retardation of speed of this deep ocean current..time to get very sweaty palms and forhead.

  246. gringo:

    Hank,

    Ok but what about 2006 and 2007 being cooler than several previous years?
    Moreover the UK Met office recently predicted that
    “temperatures will stall because of natural climate effects that have seen the Southern Ocean and tropical Pacific cool over the past couple of years.”

    “The forecast from researchers at the Met Office’s Hadley Centre in Exeter reveals that natural shifts in climate will cancel out warming produced by greenhouse gas emissions and other human activity until 2009″

    http://www.guardian.co.uk/environment/2007/aug/10/weather.uknews?gusrc=rss&feed=science

    It’s not too hard to predict what the denial camp will do if there won’t be record breaking year until 2010.

    And just what are these “natural climate effects” which have cooled the Southern Ocean and tropical Pacific?

  247. Øyvind:

    People keep referring to scientific consensus as it was the same as the Conclave reaching a consensus of the new Pope before sending out white smoke, or that me and my buddies reach a consensus of leaving the pub due to intoxication and a common realization that we must get up for work the next morning.

    Well, the layman definition of consensus may include these examples. In science it is rather less democratic. A theory reaches consensus by constantly being evaluated for its success-rate. Consensus may be reached when a high-level theory successfully explain a matrix of lower-level theory-structures. The greenhouse gas (GHG) theory is such a theory (in reality the top-level theory that IPCC has as consensus should probably be denoted ‘theory of climate change’ or something similar, however I will keep GHG here). The GHG-theory allows theories from i.e. physics, chemistry, biology and geology to interact inside one coherent understanding at the same time while sustaining all fundamental scientific laws (i.e. gravity, radiation, friction etc). If a branch of science identify an area where the global warming theory yield conflicting or even impossible consequences, the theory of GHG is regarded under attack. However, such inconsistencies are not enough to falsify the theory. The continued success of the theory in other and more substantial areas safe-guard the theory, while studies are carried out to try to resolve the mismatch or a new and better top-level theory (the sun-volcano alone theory?) start to explain the different science branches and data-matrix. This is what commonly is known as ‘normal science’.

    What does this philosophical reflection do under this post? I think that BBC and Gavin’s post fundamentally explain why there is such a strong consensus of the GHG-theory. There simply exists no over-arching consistent theory that can do what the GHG-theory enables in terms of revealing insight and explanation of such a wide web of sub-disciplinary theories, hypotheses and data. As long as the ‘sceptics’ keep throwing around stand-alone hypothesis (often without publishing them) there simply exists no alternative. A scientific theory must explain a large subset of inter-woven sub-theories and hypotheses. This is the largest challenge for the sceptic community: Join all the bits and pieces together into a coherent theoretical alternative. And remember, this new theory can not only explain the last 100 years, it must shed equal insight on glacial climate, the Tertiary warmth (i.e. it must be general). The theory must thus be time-independent. The theory must furthermore give predications that can be tested while acknowledging all scientific laws etc etc. This is the only scientific approach – and one that every “consensus-scientist” follows every day by critically gaining data, developing theoretical consequences and creating, testing and refuting hypotheses.

    I believe this may illustrate the difference between the scientific consensus that IPCC represent and the sceptical alternative. In the first case consensus is reached by scientists from different disciplines acknowledging that their respective theories and data are best (not perfectly!) explained by the GHG over-arching and constantly evolving theory (biologists have consensus regarding evolution as their top-level evolving theory). That for example 19 000 sign some petition is “hand-raising consensus” where any individual may have any of multiple (and conflicting/inconsistent) reasons to sign. This does not, however, provide coherent scientific insight or explanation and is thus scientifically valueless.

  248. Anthony:

    I have a few questions:

    1. Will the increase in water vapour caused by AGW expected to result in an increase in cloud cover?
    2. To what extent do the current models used by the IPCC factor in the albedo effect of clouds. I realise they are part of the models, but do the models allow for a change in cloud cover similar to the way they allow for changes in snow cover.
    3. Is there a definitive source (preferable a paper) on changes in global cloud cover in the last few decades?
    4. This is a bit of a supplementary question that has been on my mind over the last 6 months: The models didn’t predict the current non-warming (and likely cooling this year – la Nina?) back in 2002. I realise they aren’t (weren’t) capable of showing short term variations, but as mentioned in post 246. the Hadley Centre seems to be able to predict changes at a much higher resolution – only 4 years. Does this Hadley model show the 6 year plateau we have just experienced and if so, to what was the cause attributed?

    I look forward to your replies.

  249. Ray Ladbury:

    Gringo, Oh they will certainly argue that way–just as they take every cooling after an El Nino year to mean the end of the warming epoch. But denialists are not evidence based–they will find ways of arguing their position in contravention of the evidence no matter what. As the history of quantum theory shows, when people adopt unreasonable positions–even people as brilliant as Einstein–science marches around them. You have to go with the preponderance of evidence.

  250. Dan W:

    Lawrence Coleman (#242, 243),

    The IPCC agrees with you.

  251. Hank Roberts:

    Gringo, use the ‘Search’ box, top of the page; for example

    http://www.realclimate.org/index.php/archives/2007/01/el-nino-global-warming-and-anomalous-winter-warmth/
    and
    11ºC warming, climate crisis in 10 years?
    http://www.realclimate.org/index.php?p=115

  252. tamino:

    Re: #246 (gringo)

    Ok but what about 2006 and 2007 being cooler than several previous years?

    Using GISS data, 2007 is on track to be the 2nd-hottest year ever, second only to 2005.

    And the idea that every year should set a new record is nonsense. Statistically, we expect most years *not* to set a new record since the “scatter” in annual averages is about five times as large as the trend.

  253. san quintin:

    Gringo
    I think that Tamino has a recent post suggesting that 2007 is likely to be the second warmest year on record…after 2005.

  254. Rod B:

    Gavin, re 241. I’ll grant that you certainly know how to read NASA’s words better than most. But which “large changes seen in Arctic climate in recent years” that are now maybe not thought to be a result of GW were they referring to?

  255. wayne davidson:

    #252, Tamino, #2 worldwide, #1 for the Northern Hemisphere, despite all the heat required to melt all that extra Polar ice. Don’t know why there is a difference between the Met office and NASA, but do know (by observations in the Arctic) that NASA is right…

  256. Hank Roberts:

    Wayne, you might find the difference in the models here (not sure, I think I recall that Met and NASA differ in how much data they incorporate concerning polar latitudes)
    http://curry.eas.gatech.edu/ARCMIP/

    Arctic Regional Climate Model Intercomparison (ARCMIP) aims to improve the simulation of the Arctic regional climate in numerical models. The primary ARCMIP activities focus on coordinated simulations by different regional climate models and general circulation models. Output from these models are compared and evaluated using observations from satellites, in situ measurements and field experiments. The first ARCMIP intercomparison Project is using data obtained in 1997/1998 during the SHEBA (Surface Heat Budget of the Arctic Ocean) http://sheba.apl.washington.edu/.

  257. Geoff Wexler:

    #Andre 177
    “So the bottom line is that the anthropogenic global warming hypothesis can be considered scientifically feasible if no-one is able to falsify it.”

    Writing as a non expert …..
    Although I am not a fully paid up Popperian , I don’t think that the above remark does justice to the falsification idea. Here are some thoughts:

    1. Different theories are more or less falsifiable. Theories which are almost non falsifiable fall on the wrong side of Popper’s demarcation line which mean that he would describe them as non-scientific. That conclusion is subjective and may be controversial. Anyway my point here is just to consider some examples. The most falsifiable theory is one which claims to be exact. Examples are relativity , quantum mechanics or nearly exact laws like the conservation of energy or second law of thermod. In all these cases a tiny anomaly may not be acceptable and might falsify the theory.

    2. Andre’s phrase “if no-one is able to falsify it” concerns itself with quite a different issue i.e. whether we can should worry about the theory’s predictions not whether the theory is scientific. Notice that I did not write whether the theory is “right” because that language has to be replaced with words like “well corroborated”

    3. Applied science often uses approximations and has “loose joints” it is harder but not impossible to falsify than the basic theories just mentioned (called Gold Standard theories by Penrose) just mentioned. They can be typically easier to corroborate (and thus harder to falsify) because of the error bars involved. Engineering and climatology fall into this category. That does not mean that they are non-scientfic. But if a particular such theory has too many adjustable parameters (I am not saying that it does) it would make it that much worse from the standpoint of Popper. First principles theories are less flexible and hence more falsifiable. Thus in sold state physics you can esily fit the phonon spectrum of one solid by a bedstead model (lots of springs) provided you have enough parameters but it is preferable if you can start from first principles. In climatology an example might be clouds ; they are supposed to be hard to understand from first principles basic physics ; if they are parametrised it is important that this process does not provide too much freedom otherwise the “theory” would be reduced to curve fitting. This practice is not necessarily flawed; but it might restrict the applicability of the output. (Vague thought unfinished).

    4. Comment 187 by Timothy Chase. Interesting. I prefer your examples to those rather trivial examples of auxiliary hypotheses given by Popper.

    5. Falsifiability and climate models ? (here is where my amateurish approach might show through). Consider a projection of the warming by say 2030. What is this? I think that this might be better thought of as a singular statement not a universal one. i.e as prediction not a universal theory consisting of an infinite number of predictions. That would mean that the asymmetry between falsification and verification does not apply. Wait until 2030 amd see. Singular statemnts cane be verified as well as falsified. (Popper does discuss this sort of thing).

    You can also think of this projection in terms of the falsifiability criterion but I don’t like the resulting argument . This is how it would go: You would need a whole pile of planets. You would have to interpret the climate model as a “universal synthetic statement” (sorry Popper’s jargon). The theory would apply to every planet. So having tested it on a thousand planets and found that it worked every time a skeptic could come along and say “climate change is not a fact; induction is not rigorous, the next time you use your model it might break down !

    Perhaps a better argument would go like this: Test the model over one decade. Result is false.
    Check that is data OK. Conclusion ; cannot use model for next 20 years . Definite conclusion.
    OR result it true. Cannot be sure that model will work over 20 years but encouraged to try it. Conclusion now indefinite; this demonstrates the asymmetry principle.
    It works again. Model is even more likely to be useful for next 20 years. This shows both the asymmetry and the practical value of the inductive method which most people use.

    6. Falsifiability and initial conditions. Yet another complication. Climate change depends on the emissions and the aerosols etc. etc. Popper discusses all this as a mixture of singular statements (the data) and the universal statements (the theory). If a test on this fails what have you falsified? It could be the initial conditions , it could be the theory.

    7. Consensus. (Not in the index of Popper’s book). In my view this is just another version of the induction problem. To be absolutely sure you need a consensus over an infinite number of publications. Logically impossible. But notice that the best approximation is a consensus at a late date i.e covering a lot of research.

    Incidentally Keith’s statement in #11
    i.e. “as a rule of thumb I’d say the scientific consensus is more
    often wrong than right.”

    should be restated as “… is more likely to be replaced by a contrary consensus within N years than to survive intact”

    This version can tested, but as John Mashey has implied this generalisation would be more applicable to a young subject and some of the main conclusions concerning global warming are not young.

    With apologies for saying the obvious in a long winded way. That is what discussions about Popper seem to involve. I think that the only point of significance is the obvious one that too many adjustable parameters can be dodgy.

  258. Ike:

    I read the BBC article, and I had one question regarding number 7. Why do you not think that the skeptic’s view on this is correct? What does it matter if there is more CO2 now than there was before? If CO2 has always risen after temperature has, why should it be different now, no matter how much more CO2 is in the atmosphere?

  259. Steve Bloom:

    Re #254: Rod, the badly phrased sentence you keep quoting was written by a NASA PR person who was trying to make the research results sound as important as possible (and also IMHO covering a little bit for the fact that the purpose of the press release was to announce new results appearing to show the reversal of the trend discussed in the April paper). The “large changes” refer to the AO itself.

  260. J.C.H.:

    Rod B.

    This is the original post:

    Given the NASA revelation in the last day or two that the Arctic warming is mainly a function of current variability, there are a lot of people with egg on their face at the moment. I’d like to ask the poster of #8 to think about the same question he posed for John Christy… what do you think about the Arctic melt now?

    [Response: Do you have a link? This is very unlikely to be true. - gavin]

    I went and found a news source of the type that might lead somebody to misinterpret the study’s findings to such an extent. I found it on Fox, which was my first choice.

    From the NASA press release it sounds like some people had speculated that variations in AO might be caused by GW. On google scholar I’ve been trying to find a study that makes that claim, but so far no luck. It would be interesting to find out just how strongly GW was presented as a possible cause.

    The original post jumped to claiming the Arctic warming and melting is being caused by the reversals in Arctic ocean circulation, and not by AGW, or at least I think that is what he was saying.

    if you read this carefully, I think you can see how the seeds for the weeds of misconception were planted by FOX:

    Perfectly Natural

    Many global warming activists point to changes in the arctic icecap as proof of the dangerous effects of man-made global warming. Now a report from NASA’s Jet Propulsion Laboratory says those changes are in fact the result of natural ocean circulation patterns. A team of scientists used satellite and deep-sea pressure gauge data to monitor ocean patterns.

    Says team leader James Morison of the University of Washington’s Polar Science Center — “Our study confirms many changes seen in upper Arctic Ocean circulation in the 1990s were mostly decadal in nature, rather than trends caused by global warming.”

    The study was done on Arctic oscillation and Arctic Ocean circulation, not the ice cap.

    I thought this was the most interesting paragraph from the Nasa press release:

    Morison cautioned that while the recent decadal-scale changes in the circulation of the Arctic Ocean may not appear to be directly tied to global warming, most climate models predict the Arctic Oscillation will become even more strongly counterclockwise in the future. “The events of the 1990s may well be a preview of how the Arctic will respond over longer periods of time in a warming world,” he said.

    That old man AGW just keeps rollin’ along right back into the picture.

  261. wayne davidson:

    Thanks Hank, there has been a remarkable increase in Arctic temperatures
    since the Sheba project. 1997-1998 marked the beginning of noticeable Arctic climate change, with every subsequent year having something new or unusual to behold. It got really stranger in 2004-2006 period when Arctic stations started to report unheard of near +10 C monthly anomalies, interspersed at many locations, making it obvious that the heat was on really strong at least in one region. It all culminated to the great melt of the summer of 2007. All in line with a substantial increase in tempertatures, not what was often said from contrarian sources, a levelling of the temperautre trend, nothing resembles to temperatures as usual here, every Arctic location was warming, assymetrically or at times the entire region simultaneously. A temperature anomaly chart not showing this growing trend should be seriously questionned.

  262. Eli Rabett:

    Wayne, let us hope it culminated this September. The scarier thought is that it did not.

  263. Timothy Chase:

    wayne davidson (#261) wrote:

    All in line with a substantial increase in tempertatures, not what was often said from contrarian sources, a levelling of the temperautre trend, nothing resembles to temperatures as usual here, every Arctic location was warming, assymetrically or at times the entire region simultaneously. A temperature anomaly chart not showing this growing trend should be seriously questioned.

    I am able to perceive depth only because my eyes do not see quite the same things. The differences between Hadley and Nasa can be useful so long as we keep in mind what they are. I presume Hadley wanted to preserve the continuity with the earlier historical record, and if so that may very well justify their approach.

  264. Timothy Chase:

    J.C.H. (#260) wrote:

    I thought this was the most interesting paragraph from the Nasa press release:

    Morison cautioned that while the recent decadal-scale changes in the circulation of the Arctic Ocean may not appear to be directly tied to global warming, most climate models predict the Arctic Oscillation will become even more strongly counterclockwise in the future. “The events of the 1990s may well be a preview of how the Arctic will respond over longer periods of time in a warming world,” he said.

    That old man AGW just keeps rollin’ along right back into the picture.

    Sounds to me like a classic case of projection…

    If this picture were applicable to the real climate system, it would imply that anthropogenically forced changes in climate would project primarily onto the principal patterns of natural variability, even though such natural variability may occur predominantly on timescales much shorter than that of the imposed forcing.

    [... and later]

    On the basis of the approach presented here, it is possible that this bias is a response to anthropogenic forcing (recent model integrations confirm a strong effect of anthropogenic forcing on the Arctic Oscillation).

    Signature of recent climate change in frequencies of natural atmospheric circulation regimes (abstract only)
    S. Corti, F. Molteni, and T. N. Palmer
    Nature 398, 799-802 (29 April 1999)
    http://www.nature.com/nature/journal/v398/n6730/abs/398799a0.html

    ;-)

  265. Timothy Chase:

    Geoff Wexler (#257) wrote:

    4. Comment 187 by Timothy Chase. Interesting. I prefer your examples to those rather trivial examples of auxiliary hypotheses given by Popper.

    The argument is essentially that of Pierre Duhem. Duhem’s Thesis, 1892.

    Preceded Popper’s first formulation of the Principle of Falsifiability by approximately 50 years, and if correct demonstrates that it is unworkable, strictly speaking.

    *

    However, I like the idea of a theory being “more or less falsifiable.”

    In essence, one could reinterpret Popper’s Principle of Falsifiability along weaker lines and argue that it is a normative principle in accordance with which scientific theories out to be constructed so that they are as close to being falsifiable as possible. And what would this mean? That they should strive to make risky, specific predictions, where by “risky,” one means predictions such that if the theory is not correct, the predictions would have a small probability of being true.

    *

    Geoff Wexler (#257) wrote:

    7. Consensus. (Not in the index of Popper’s book). In my view this is just another version of the induction problem.

    How about consciousness? What evidence do you have for distinguishing between what you are aware of and the you that is aware? But if such a distinction is not taken for granted, will it make any sense to speak of “theory” or “methodology”?

    Geoff Wexler (#257) wrote:

    To be absolutely sure you need a consensus over an infinite number of publications. Logically impossible. But notice that the best approximation is a consensus at a late date i.e covering a lot of research.

    Within the context of either induction or consensus, I don’t worry about being “absolutely sure.” This is the reason why I specifically conclude 187 with the sentence:

    Third, in science, one must regard many statements as true even if the justification of these statements does not admit of absolute certainty. Much of our knowledge is corrigible.

    *

    But to approach this from a different perspective and setting aside Duhem for the moment, is the Principle of Falsifiability itself falsifiable? Would it be able to perform its role as a principle for the demarcation of scientific discourse from other forms of discourse if it were falsifiable?

    Popper thought that other forms of discourse (e.g., regarding art, philosophy, or ethics) were meaningful. A good thing, too, since the Principle of Falsifiability would only appear to be able to perform its role of demarcation if it were either a universally recognized tautology (which it clearly isn’t) or a normative principle stating in essence how science ought to be done — which is of necessity not falsifiable.

    *

    In any case, I would argue that at any given moment, the individual is quite limited in terms of what they can articulate in words or thought. There is a great deal which they must simply take for granted in order to live and think in the world, a great deal which remains tacit. Their senses are part of their means of awareness, but so is their personal history, and so too is the society into which they were born and live.

    Likewise, when formulating a test for a given theory so that it may be “testable,” generally there will be a great deal which must be taken for granted, assumed to be true. That is the consensus, and that is the function of consensus in science. Elements of the consensus may of course be brought into question and subject to tests, as well, but never the totality — except as a philosophic exercise.

    *

    This of course brings us back to Duhem’s thesis. Given the role of the consensus, science is fallible, but it can also be self-correcting.

  266. Geoff Wexler:

    re #258 (Ike).

    Short answer : Because time and speed are of the essence in all dynamical problems. In addition the measured rise in CO2 has been shown to be man made and has not come out of the oceans as in the past (Discussed somewhere on Realclimate). Just one piece of evidence is that the oceans are not liberating CO2 now is that they are becoming less alkaline (acid ocean effect).

    But the skeptics could end up by being right in a way which would not please them (or anyone else).

    There are already signs that the oceans are taking up less CO2. If it gets much warmer these sinks could turn into sources just as they were in pre-history. The same could happen with other sinks. So some way down the line (centuries ?) it might once more appear that temperature changes lead CO2 changes. But that would not stop the physics; it would still be true that CO2 would create more warming. This double cause and effect happens in all positive feedback loops. The novel feature of that one would that it would have been initiated by humans in contrast to earlier ones which were started naturally (e.g by orbital changes of the Earth)

    Incidentally Gavin’s introductory reply to the BBC on this point includes the word “irrelevant”. I don’t quite agree. The trouble is that quite a few well educated people have asked me about just this point (not the others) and they didn’t like the official answers they found on web sites(compare Ike above). This is because they had to choose between two incomplete accounts. Yes it is irrelevant to the attribution of recent warming but not to people’s view of the bigger picture. The lag is essential evidence for climatological theory not against it as argued in GGWS and elsewhere. I think the judge in the recent “Al Gore trial” in the UK was similarly irritated by too much abridging.

    I wrote a longer answer (no doubt too long) which is available in Section 5 of the document at

    http://zcarb.net/wordpress//uploads/ggws.html

    (Incidentally I included an argument based on breaking down the CO2 into two terms one of which always precedes the temperature. So the statement that CO2 follows the T is never quite right; it depends on which of two terms is dominant)

  267. Ray Ladbury:

    Re 258. Ike, indeed rising temperatures will probably ultimately cause natural sources to rise–a positive feedback that may represent a point of no return for climate change. There is already evidence of this happening from peat bogs in Siberia. The difference is that most previous warming epochs didn’t start with greenhouse gas warming–the outgassing merely acted to intensify and prolong the warming event. Where the denialists err is in assuming that this means greenhouses can’t be a cause of warming.

  268. Lawrence Coleman:

    Re 258 Ike. Again if you have seen an inconvenient truth which incidentely had been widely applauded amongst climate scientists for being very very accurate; you would have seen the graph for CO2 vs Temp over the past 650 thousand years. the two practically mirror each other..they are very chiral indeed! Ask gavin why CO2 leads temp as I’m not the best person to ask. The fact remains that CO2 and Temp are inseparable and one directly affects the other.

  269. dean_1230:

    re #265

    Just a question. are we sure this warming trend started with GHG-warming? if you look at more than a 30 year view, the current warming trend started in the early 1800s and really took off in the early 1900s. There was a modest colling from 1940-1970, but the warming trend is almost 200 years old where the CO2 rise didn’t really take off until the mid-1900s.

  270. Dan W:

    dean (# 269)

    Fossil carbon emissions began around 1800 (with the industrial revolution) but didn’t really get going until after 1900:
    http://en.wikipedia.org/wiki/Image:Global_Carbon_Emission_by_Type.png

    AGW didn’t really get going until after 1900:
    http://en.wikipedia.org/wiki/Image:2000_Year_Temperature_Comparison.png

    The 1940-1970 period was affected by unrestrained coal particulate emissions that were reduced in most of the industrialized nations after the 1970s. These emissions including sulfur dioxide have strong climate cooling properties, but have much shorter atmospheric lives than CO2. After the 1970s most of them “fell out” of the atmosphere but most of the CO2 didn’t and won’t for a long time.

  271. Ray Ladbury:

    Dean_1230, there is certainly some doubt about the origin of warming prior to ~1950. However, reasonable variations in solar radiation coupled with anthropogenic emissions can explain them quite will. Solanki has shown that even if you assume that ALL the warming prior to 1970 (I think) was due to solar activity, you can’t reproduce the warming since. Also, remember that forcing is logarithmic in CO2 concentration.

  272. Hank Roberts:

    dean_1230, don’t assume the trend results from only human activity; the trend is the result of all the forcings, including human activity.

    See the ‘Start Here’ link and the AIP History (left side of page under Science) for the information to help you answer your question.

    You can check your assumptions too, by looking the numbers up, for example:
    http://www.blackwell-synergy.com/doi/abs/10.1034/j.1600-0889.1999.t01-3-00002.x

    “… carbon dioxide (CO2) emissions from fossil-fuel use for the years 1751 to the present. The time series begins with 3 × 106 metric tonnes carbon (C). This initial flux represents the early stages of the fossil-fuel era. The CO2 flux increased exponentially until World War I. The time series derived here seamlessly joins the modern 1950 to present time series. Total cumulative CO2 emissions through 1949 were 61.0 × 109 tonnes C from fossil-fuel use, virtually all since the beginning of the Industrial Revolution around 1860. The rate of growth continues to grow during present times…”

  273. Hank Roberts:

    One more for Dean:
    http://gcmd.nasa.gov/records/GCMD_CDIAC_CO2_EMISS_MODERN.html

    The first half of the fossil fuel so far burned was burned before about 1970, when the Clean Air Act first limited dirty smoke from coal plants to some extent. The second half since 1970 has been burned somewhat cleaner, though the ‘third half’ burned in India and China is pretty dirty again.

  274. David B. Benson:

    Geoff Wexler & Timothy Chase — Most interesing posts. It sounds to me that you are both approaching the Bayesian view of science.

  275. Laphroig:

    Re#240: Chuck, thank you for your review of the great variety of those things I had in mind when I wrote the sentence immediately following the one you quoted (in #222), which reads, “Of course we add various systems that attempt to augment memory by inserting some sort of “objective” devices (thermometers) or systems (record keeping and adjustments) to counter the pure subjectivity of sense experience.”

  276. Raplh Smythe:

    Ray Ladbury. If you think “CO2 levels are up 33% since the start of the industrial era, there’s warming, it’s bad, and it’s caused by CO2 and we have to do something” is a detailed explanation of what’s going on, you’re certainly entitled to your opinion. Or were you not trying to disagree that land-use chaanges, aerosols and soot have an impact on climate as do CO2 and methane et al? Just to make myself clear: I am NOT trying to argue CO2 isn’t a forcing, since it is. Okay?

    Wayne Davidson. Are you really trying to compare a substance measured in parts per billion to one that that’s measured in parts per million, and that aren’t similar in either behavior or chemistry? I’m not trying to dispute that GHG are a big part of what’s going on, I’m simply saying up that CO2 = higher temps is an incomplete picture of what’s going on, and ignoring all else is not particularly helpful either in understanding the big picture or influencing policy.

    Barton Paul Levenson. I’m not misunderstanding anything, I agree with you when you say “unless some countervailing process is blocking it”. That’s my point about land-use changes, aerosols and soot and so on, and ignoring the GHG. Soot on ice makes it melt faster. Sulphur in the air reflects sunlight. Questions: How much energy does 100 ppmv extra CO2 create? How much energy do melting clouds absorb? How much energy does water chaning to water vapor absorb? How much energy does 1050 ppbv extra CH4 create? And so on and so forth.

    So we model them and we get an idea of what the system is doing. And the system is not just 1 thing. Does anyone dispute that? What are we arguing about?

    Jim Eager. I didn’t say it was a harmless trace gas, just that it was a trace gas. I’m not disputing its effects nor that we’re causing additional amounts of it. I’m simply saying there are other non-GHG factors to consider. That the half-life of methane is 7 years and it’s 20% of the radiative forcing is just as interesting as carbon dioxide etc, but ignoring the other factors is like ignoring the GHG. It’s a system.

    David B Benson. I don’t disagree with you. I wasn’t trying to really discuss CO2 but since that is what everyone seems to focus, I used it. I could have said CH4 or O3. That’s not the point, it’s not all there is in the system. Let me boil down what I’m saying “There are other factors to consider besides GHG.” That’s it. Not trying to say component x does or does not do y. Does my bringing it up brand me as making an ideological point? Because I’m not. I’m just saying you can’t ignore the -0.2 to -0.8 W/m² radiative forcing range suphates, the +0.1 to +.04 of black carbon, or the effects of sea-salt aerosols and how they differ between the hemispheres. Do we really need to discuss the basics instead of the mitigation and adaptation strategies?

    Or does anyone disagree with

    While the radiative forcing due to greenhouse gases may be determined to a reasonably high degree of accuracy… the uncertainties relating to aerosol radiative forcings remain large, and rely to a large extent on the estimates from global modelling studies that are difficult to verify at the present time.

    That’s all I’m saying. Sorry if it’s nonsense and misinformation to anyone. Or does everyone just like to ascribe motivations, talk past each other, and argue about the details?

  277. CobblyWorlds:

    JCH,

    Try these papers re the AO and ice melt.

    Rothrock & Zhang, 2004, “Arctic Ocean sea ice volume: What explains its recent depletion?”
    http://psc.apl.washington.edu/zhang/Pubs/rothrock_zhang_2004JC002282.pdf
    I quote:
    “By separating the ice response into thermally and
    wind-forced components we find that the thermal component
    of the response shows the volume of both undeformed
    and ridged ice rather steadily declining since the 1960s. The
    wind-forced component unexpectedly does not exhibit a
    decrease of ridged ice, but it does exhibit a highly varying
    but continually decreasing amount of undeformed ice.”

    Rigor & Wallace, 2004, “Variations in the age of Arctic sea-ice and summer sea-ice extent.”
    http://seaice.apl.washington.edu/IceAge&Extent/Rigor&Wallace2004.pdf
    I quote:
    “The transition to an Arctic Ocean dominated by
    ‘young’ ice occurred abruptly in 1989–1990 when the
    AO-index was over 2 standard deviations above normal.
    The reverse transition from present day conditions to a state
    like that which prevailed prior to 1989, with large areal
    coverage of old, thick ice, would obviously take much
    longer…

    …The winter AO-index explains as much as 64% of
    the variance in summer sea-ice extent in the Eurasian sector,
    but the winter and summer AO-indices combined explain
    less than 20% of the variance along the Alaskan coast,
    where the age of sea-ice explains over 50% of the year-toyear
    variability. If this interpretation is correct, low summer
    sea-ice extents are likely to persist for at least a few years.
    However, it is conceivable that, given an extended interval
    of low-index AO conditions, ice thickness and summertime
    sea-ice extent could gradually return to the levels characteristic
    of the 1980’s.”
    Or they could go t’other way. ;)

    And as I was reminded of this recently (here at RC) and it addresses a possible anthropogenic role in the AO behaviour: Shindell et al 1999 “Simulation of recent northern winter climate trends by greenhouse-gas forcing.”
    http://pubs.giss.nasa.gov/abstracts/1999/Shindell_etal_1.html
    I quote:
    “we use several different climate-model
    versions to demonstrate that the observed sea-level pressure trends,
    including their magnitude, can be simulated by realistic increases in
    greenhouse-gas concentrations. Thus, although the warming appears
    through a naturally occurring mode of atmospheric variability, it
    may be anthropogenically induced and may continue to rise. The
    Arctic Oscillation trend is captured only in climate models that
    include a realistic representation of the stratosphere, while changes
    in ozone concentrations are not necessary to simulate the observed
    climate trends.”
    (I’m sure I’ve read something more recent and better than that – but I can’t put my finger on it.

    By the way the seaonal sea ice plot is well worth looking at in tandem with all this.
    Top right of this page at Cryosphere Today: http://arctic.atmos.uiuc.edu/cryosphere/

    Now I really must desist from posting and get back to reading.

    #265 Timothy Chase,
    I’m not ignoring you’re earlier post – I just can’t think of an intelligent thing to say in response, so I’ll just drag my rhetorical knuckles – I still “like” theories to make falsifiable predictions.

  278. Hank Roberts:

    Raplh, you wrote: “… yanking it out because it looks correlated…”

    That’s why people suggest you use the “Start Here” link at the top of the page, and the AIP History link (first one under Science).

    Your belief that the concern is based on just eyeballing the charts — your belief that the change in CO2 just ‘looks correlated’ — is the odd bit that stands out in what you wrote.

    Why do you believe that’s the reason that people attribute climate change to changes in CO2? Do you get that from some source you consider reliable? Did you read that somewhere you trust?

    Because the links people are pointing to will give you the history of how CO2 has been studied and the reasons for the concern.

    Anyone reading RC for a little while has come across the Feynman quote: “Science is what we have learned about how to keep from fooling ourselves.”

    CO2 is connected to global warming by a lot of work, not by “… yanking it out because it looks correlated …”

    That wasn’t what you meant? You could say so and move on. We’ve all misspoken and corrected ourselves (with eager help from our fellow readers here) from time to time.

    Sounds like you agree on all the other point of fact so far raised.

  279. CobblyWorlds:

    #223 Ellis
    Very sorry, my post #232 was a reply to you #223.

  280. Timothy Chase:

    CobblyWorlds (#257) wrote:

    #265 Timothy Chase,
    I’m not ignoring you’re earlier post – I just can’t think of an intelligent thing to say in response, so I’ll just drag my rhetorical knuckles – I still “like” theories to make falsifiable predictions.

    Not a problem.

    I will emphasize the interdependence which exists between scientific theories, and strictly speaking this is incompatible with Popper. (See comment 187.) The emphasis I place upon a tacit expert consensus (comment 155) is an outgrowth of my recognition of this interdependence. However, like foundationalism, naive theories of induction focus on the role evidence while omitting the role of counterevidence, and we need to consider the role of both in the scientific method. Popper brought to our attention the role that counterevidence plays in the the scientific method and this insight should be preserved. We can do this by regarding falsifiability not as a matter of either/or but as a matter of degree.

    You seem to already be doing this:

    1. Different theories are more or less falsifiable. Theories which are almost non falsifiable fall on the wrong side of Popper’s demarcation line which mean that he would describe them as non-scientific. That conclusion is subjective and may be controversial. Anyway my point here is just to consider some examples. The most falsifiable theory is one which claims to be exact. Examples are relativity , quantum mechanics or nearly exact laws like the conservation of energy or second law of thermod. In all these cases a tiny anomaly may not be acceptable and might falsify the theory.

    Comment 257

    But in this case, it might be better to speak of testability rather than falsifiability, and disconfirmation rather than falsification. And then we would indeed be moving in the direction of “the Bayesian view of science” – as David A. Benson suggested earlier. (See 274.)

  281. Rod B:

    re 259, 260: Steve, you say that a PR guy got it a little less than technically accurate or puffed it up a bit. I guess I can accept that, though I would expect NASA to be much better at their PR than that. So be it.

    JCH, I’m having trouble following your argument (not even totally sure which side of the fence….). But assuming you’re in support of the NASA piece you do a tremendous amount of tap dancing to get around the simple fact that, if the piece did not refer to ice melt then it simply got over-hyped by PR, ala Steve above. Blaming Fox for the “misread” is simply ludicrous. You try way too hard.

    Since we’ll never know for sure the PR puffery sounds logical and I’m willing to let it be as kind of a no-op. Besides, this is detracting from a bunch of interesting posts in this thread.

  282. Raplh Smythe:

    Hank. By “yanking it out” I meant “treating it as a single un-related variable” or some such.

    I do in no way dispute that (depending on source) it is 9-26% of the greenhouse effect, has a radiative forcing of about 1.49-1.83 watts per square meter, a global warming potential of 1 and a measured amount of almost 400 ppmv. Just like I don’t dispute that water in all its forms is 90% of the effect but that we can’t directly influence the concentration of water vapor. However, we do influence clouds, by the same mechanism by which we produce the CO2 etc. Don’t think 169 ug/m3 of particulates in Cairo Egypt has a bearing on anything there? If you want to talk about 33% more carbon dioxide, why not 150% more methane, about a quarter of the radiative forcing of well mixed GHG? Why leave off nitrous oxide and the chlorflorocarbons? Why not look at the 5 other things rather than burning fuel for transportation that create carbon dioxide? There’s more to worry about and other compounding factors here.

    All I’m saying is CO2 doesn’t exist in a vaccuum. It’s disturbing to me that it’s accelerated from about a 1% a year to 3% a year since the ’90s, sure. If the percentages hold, and CO2 is 10% of the GE, then it’s gone from ~6% of the GE since the early 1800′s. Is it the only thing to be concerned with? No.

    I’d imagine I get my information from the same place you do. Unless you’ve moved onto the AR4 which I have not. For example
    http://www.grida.no/climate/ipcc_tar/wg1/fig6-6.htm
    http://www.grida.no/climate/ipcc_tar/wg1/237.htm
    http://www.grida.no/climate/ipcc_tar/wg1/251.htm

    And so on. Or http://en.wikipedia.org/wiki/Greenhouse_gas
    I’m supposing that they’ve got info on there that’s newer than the TAR.

    Look at this graph and tell me what you take out of it:
    http://upload.wikimedia.org/wikipedia/commons/7/77/Vostok_420ky_4curves_insolation.jpg

    More for ya.

    http://en.wikipedia.org/wiki/Greenhouse_effect
    http://en.wikipedia.org/wiki/Image:Atmospheric_Transmission.png
    http://en.wikipedia.org/wiki/Image:Solar_Spectrum.png
    http://www.globalwarmingart.com/images/thumb/b/bb/Holocene_Temperature_Variations_Rev.png/350px-Holocene_Temperature_Variations_Rev.png
    http://en.wikipedia.org/wiki/Image:Phanerozoic_Carbon_Dioxide.png

    I’m just asking why all the focus on CO2, and wondering if it’s useful to focus on, or if there are better things to advance policy. The science is settled.

    Let me try this again. “CO2 is not the only variable.” That’s all I’m saying.

  283. Steve Bloom:

    Re #281: Rod, actually I do blame Fox for the mis-read since the release did include an explicit statement that the melt trend was not implicated in the changes being discussed.

  284. ray ladbury:

    Ralph, CO2 is the variable that we have changed that has caused the problem. It stands to reason that by reversing those changes we would alleviate the problem with the least unanticipated, adverse effects. CO2 is the 2nd most important gas, and the only one we can reduce that will significantly reduce warming. CO2 is extremely long-lived, and other “knobs” we can turn are much shorter lived. We understand the physics of CO2, but much less so that of aerosols and other variables. Other “knobs” likely have other adverse effects. In short, everything we understand about climate suggests that by messing with the system any more than you have to, you will likely cause as many problems as you solve.

  285. Hank Roberts:

    Raplh, here: http://www.giss.nasa.gov/research/news/20020919/chart1.jpg
    Here: http://www.giss.nasa.gov/research/news/20020919/

    “.. the ‘alternative’ scenario will not be easy to achieve. It requires that the world begin to reverse the growth of true air pollution (especially ‘soot’ and the gases that control surface ozone, including methane) and also that we flatten out and eventually begin to decrease CO2 emissions.”

    That’s just one example. There are many others in the current science.

    You’re arguing against a strawman or a myth. Not the scientists, not those of us here who are just reading the science to try to learn, not even the trolls here, claim CO2 is the only variable.

    If someone told you that writers at RC say CO2 is the only variable, they lied — setting up a game of “let’s you and them fight.”

    Ain’t so. Nobody will defend that strawman.

  286. Chuck Booth:

    Re # 275 Laphroig commenting on my post # 240:

    Yes, I read that sentence, but you seemed to be dismissing, or trivializing, those measurements when you wrote “And those abstractions are far simpler than the reality of the experience of weather. They basically consist of temp, wind and humidity.” My point was that an understanding of climate is based on more than just temperature, wind, and humidity data. I would suggest, though, that a climate scientist’s understanding of climate as a physical phenomenon probably does not include “all the little variables like, how old you are, what you’re doing, and with whom, when you last ate, what you drank the night before, what you’re wearing etc.”

  287. J.C.H.:

    Rod B.,

    Look at what FOX said:

    “Many global warming activists point to changes in the arctic icecap as proof of the dangerous effects of man-made global warming. Now a report from NASA’s Jet Propulsion Laboratory says those changes are in fact the result of natural ocean circulation patterns. …”

    What changes in the arctic icecap (solid) have scientists been saying are caused by AGW? Perhaps the melting is one they had in mind. Can you agree to that?

    Are they not saying the NASA report exonerates man-made global warming in causing dangerous changes in the arctic icecap by falsely stating the report says the cause of those dangerous changes is natural ocean circulation patterns?

    The report says no such thing. The report is mostly about water, not ice.

  288. Lawrence Coleman:

    Re: Rod B
    Here again the matter is one of extent, sure there have always been periods where the artic ice cap’s thickness has varied, even the thickness of the ice and density. However if you take a graph and measure the extent of ice melt all over the world, greenland, antartica, patagonia, europe etc etc you will see an undeniable similarity in every one of them, sure some ice because of it’s density, latatide and altitude may take longer to melt than others..but I’d bet if you took a density mesurment of the ice at various depths of all these regions you will see a similar rate of change..one that the density is getting softer and softer. The changes at the artic mirrors what is happening in antartica, the italian and swiss alps, new zealand, siberia, lapland and greenland to name but a very few. You would have to have boulders in your head if you cant see an irrefutable connection between all of those. Back to ‘extent’…the extent of melting and the time frame NOW compared to the cyclical ripples of melt that have always occurred in time past is massive, ‘UNPRECEDENTED’. Those scientists on the artic out there in boats are constantly seeing huge chunks of ice come away that are thousands and thousands of years old..not the result of cyclical melting and refreezing..but eons old!

  289. Hank Roberts:

    Tobacco?

    http://www.newsdaily.com/Science/UPI-1-20071119-14575400-bc-us-heartsmoking.xml

    “Non-smoker heart attacks down after ban
    Nov. 19 (UPI) — After an Indiana county smoking ban was implemented, heart attack hospital admissions dropped 70 percent for nonsmokers — but not for smokers, a study found.” (vs. matched control)

    Ice density — that’s what GRACE does.
    Patagonia Icefield melting observed by Gravity Recovery and Climate Experiment.
    Geophys. Res. Lett., Vol. 34, No. 22, L22501. 10.1029/2007GL031871
    http://www.agu.org/pubs/current/gl/

  290. Jim Eager:

    Re Raplh Smythe @ 276: “So we model them and we get an idea of what the system is doing. And the system is not just 1 thing. Does anyone dispute that? What are we arguing about?”

    Good question. No one here has ever or would ever assert that CO2 is the only factor. So why have you implied that anyone has?

  291. Rod B:

    Et al: Here again is the direct quote from the Summary of the NASA report: “…The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.” Now any non-convoluted person could easily see that NASA was referring to the most recently discussed Arctic phenomenon — ice melt [as seemingly supported by Lawrence in 288]. They could also easily accept with minimal fuss, maybe after an explanation, that NASA was talking about something else that was once contended to be a result of AGW but now is uncertain, or that NASA was referring to something totally different, or that NASA PR mis-spoke a bit. But accepting what NASA wrote is not what they wrote, or understanding what the PR public notice said requires a PhD in climatology is beyond the pale. Tap dance all you want, but it is what it is. It is no stretch in the least to see that almost anyone would naturally read it as Arctic ice melt, even if that proves to be incorrect.

    I simply asked what NASA meant. I got two plausible, acceptable, and simple answers, one from Gavin (well, half an answer from Gavin). Why is everybody else so vociferously presenting these terribly complex defenses?

  292. Barton Paul Levenson:

    Relph Smythe posts:

    [[I’m just asking why all the focus on CO2]]

    Because that’s what’s causing most of the problem.

  293. J.C.H.:

    Excerpt from recent abstract:

    “The mean time series shows quite coherent structure. The mean series shows the Medieval Warm Period (MWP) and Little Ice Age (LIA) quite clearly, with the MWP being approximately 0.3°C warmer than 20th century values at these eighteen sites. …” – http://www.ncasi.org/publications/Detail.aspx?id=3025

    Excerpt from an earlier abstract:

    “These results suggest that 20th Century warming trends are plausibly a continuation of past climate patterns. Results are not precise enough to solve the attribution problem by partitioning warming into natural versus human-induced components. However, anywhere from a major portion to all of the warming of the 20th Century could plausibly result from natural causes according to these results. Six of the models project a cooling trend (in the absence of other forcings) over the next 200 years of 0.2–1.4 °C. …” – http://tinyurl.com/3xgtyk

    I wasn’t alive during the MWP, and I don’t expect any of my progeny, or theirs, will live through it either. Professor Loehle seems to think I’m wrong.

  294. Hank Roberts:

    Rod, Gavin and others are responding to the fake science claim from Fox News, not arguing with you. See 202 and 203 above.

  295. Raplh Smythe:

    Jim, I’m talking about the subject in general, not singling out people here, nor everyone. I started this with a rhetoical question. Why are those focusing on CO2 as if it’s the only thing in the system. I didn’t accuse you or Real Climate or anyone of saying it was. I take issue with blanket statements as if they were fact, when they’re made, by whomever makes them. There are some that do, right?

    Barton, “causing most of the problem” is too simplistic. What problem are you talking about? I’m guessing the observed warming trend. What do you mean by most? I’m guessing more than 50%, which is true if you’re talking only about the GHG part of it (not including ozone). But what about pollution? Does carbon dioxide reflect sunlight like sulphur does? Does it make ice melt faster than soot?

    It would be true to say that “CO2 is about 60% of the greenhous gas portion of radiative forcing.” or that “By itself, CO2′s radiative forcing equals that of the other anthropogenic greenhouse gasses and ozone.” You could also say “The radiative forcing of CO2 is about equal to the radiative forcing of the net anthropogenic component, if you remove every other factor.”

    At least if you’re using this chart: http://en.wikipedia.org/wiki/Image:Radiative-forcings.svg

    Would fossil fuel usage that created another 100 ppmv of CO2 (along with all the rest of the positive and negative forcings) result in more positive forcing on the net?
    Would reduction in output and sequestration of 100 ppmv of CO2 change things and result in a net negative forcing or would the rest of the system adjust? Depending on how much reduction (everything else in the system would, theorhetically be reduced) and how much sequestration (which would only remove CO2), balanced against the chemical reactions of things with each other.

    I don’t know. And I don’t care. The specifics are moot — the question now is how and what to implement to reduce anthro-GHG and pollution and how to spur that into action in an efficient cost effect way that gets results.

  296. Ray Ladbury:

    Rod, what is at issue is the implication that “change” seen in the Arctic are due to processes other than climate change. Both the press release and the Faux News report are vague wrt what changes they mean and are to be criticized for that. The implication of the Fox report–and the way the report was received in the blogosphere–were than AGW is not important in the polar regions–a statement contrary to fact.

  297. Raplh Smythe:

    Ray, Hank, then we’re in agreement. I’m simply stating there are other factors, not accusing anyone of claiming there’s not (except if they do!). It’s a statement not an argument. I’m not saying that the people writing here said that CO2 was the only variable. I’m saying it appears to me that in general it gets too much focus. Which in my opinion doesn’t advance the case for action.

    The policy focus should be the sum of anthro-GHG in total and pollution (different effect, same basic cause), while factoring out whatever part of this is land-use changes (or at least acknowledging it contributes to climate change as well.)

    Burning less fuel or cleaner forms of fuel (or using PVs, turbines, water), using new technologies to reduce the output of the dirtier forms of producing energy et al, halting deforestation, and the like, takes care of both the anthro-GHG and pollutant problems at the same time, and does not rest upon what the specifics are. If it makes sense, various components can be sequestered. As I said, the science is settled. It’s time to move on and frame the data and conclusions in terms of getting action done.

    My belief is you talk about the net gain in radiative forcing, which results in warming temperatures, and what the climate, economic, and health effects are of both the warming and of the pollution created. Then you have policy discussions to determine the cost/benefit ratio of various actions to halt or reverse various aspects. Then you implement them. Because we know it’s warming and what’s causing it.

    “Human activities—primarily burning of fossil fuels and changes in land cover—are modifying the concentration of atmospheric constituents or properties of the surface that absorb or scatter radiant energy.”

  298. J.C.H.:

    Actually, I think the NASA press release is specific:

    “Reporting in Geophysical Research Letters, the authors attribute the reversal to a weakened Arctic Oscillation, a major atmospheric circulation pattern in the northern hemisphere. The weakening reduced the salinity of the upper ocean near the North Pole, decreasing its weight and changing its circulation.

    “Our study confirms many changes seen in upper Arctic Ocean circulation in the 1990s were mostly decadal in nature, rather than trends caused by global warming,” said Morison.

    “While some 1990s climate trends, such as declines in Arctic sea ice extent, have continued, these results suggest at least for the ‘wet’ part of the Arctic — the Arctic Ocean — circulation reverted to conditions like those prevalent before the 1990s,” he added. …”

  299. David B. Benson:

    Here is a cost effective way that gets results:

    http://biopact.com/2007/11/fuelcell-energy-sells-three-biogas-fuel.html

  300. Hank Roberts:

    Raplh, now you’re asking if we might make things better, instead of worse, if we sped up burning fossil fuel.

    Another rhetorical question? I doubt anyone is asserting that.

    Best advice — ignore rhetorical questions, they’re just trolling.

  301. Raplh Smythe:

    David B Benson, thanks for the link. Cool stuff.

    Hank, you have gotten the opposite of what I’m saying (and this isn’t rhetorical). What person could possibly make any kind of coherent argument that speeding up burning fossil fuels would make things better? That’s silly.

    I’m saying focus on implementing policy and economic measures that cut pollution, which involves cutting the use of fossil fuels by conservation and stricter standards/increased efficiency, cleaning the output of what is still used, and replacing as much as possible with fuel cells, hybrid vehicles, electric vehicles, PV cells, wind turbines…

    I think it’s better to just focus on cutting pollution and let that take care of the anthro-GHG aspect of this combination issue, rather than discussing minutia like if CO2 radiative forcing is a little more than 50% of the anthro-GHG as a whole or not. Who cares. Discussing if the radiative forcing of nitrate aerosol is -.5 -.03 -.02 or -.22 does nothing towards reducing emissions. Who cares. Does sequestering CO2, regardless of how bad it is or not, reduce polution? Probably not. Does reducing fossil fuel usage reduce pollution and anthro-GHG at once, regardles of how bad CO2 is or not? Yes.

    Then the issue is framed in terms of reducing pollution by reducing emissions rather than contentious details.

    I believe framing it in terms of emissions and pollution would get more traction, and be a better way to compel action then going around in circles about what .25 means compared to .50 (or whatever)

    “Human activities—primarily burning of fossil fuels and changes in land cover—are modifying the concentration of atmospheric constituents or properties of the surface that absorb or scatter radiant energy.”

    That means the focus should be on lessening, stopping or reversing those aspects of burning fossil fuels and changes of land cover which result in perceived or likely detrimental effects to the concentration or properties, not quibbling over esoterics.

    My top detrimental of each category are pollution and deforestation.

  302. Rod B:

    Jeeeeze. JCH, you inadvertantly (sic) left off another: “…The results suggest not all the large changes seen in Arctic climate in recent years are a result of long-term trends associated with global warming.” And as I said, this one doesn’t require a PhD to read. (Though I might be off in guessing NASA press releases and PR summaries are written for the general public.) You guys are just hell-bent to show that NASA did not write what they wrote. Amazing! Especially since it is at worst a teeny-tiny insignificant roadbump in the AGW debate.

    Hank says, “…Rod, Gavin and others are responding to the fake science claim from Fox News, not arguing with you.”

    I’m befuddled. Gavin and others answered my question(s) directly. What on earth is the problem??

  303. J.C.H.:

    In the report the large changes not associated with AGW are large changes in water circulation. Arctic Ocean circulation is a large part of the Arctic climate.

    What additional large changes in the Arctic climate is the report attributing to variations in a decade-long time scales?

  304. Hank Roberts:

    Raply asked:

    > Would fossil fuel usage that created another 100 ppmv of CO2
    > (along with all the rest of the positive and negative forcings)
    > result in more positive forcing on the net?

    Yes. Burning more fossil fuel will increase the committed warming.

    Wait for it: http://pubs.giss.nasa.gov/abstracts/inpress/Hansen_1.html

  305. Raplh Smythe:

    Hank, that looks like a good paper. I’ll see if Dr. Hansen can make a compelling case for the first sentence, which seems a bit overstated, and I’m interested to see what he has to say about the subject in the last sentence. I certainly agree fossil fuels are the main driver of climate change and that we need to minimize whatever negative impacts they have.

    As far as your answer of yes, you seem to be saying that fossil fuel = CO2 and CO2 = warming after all is said and done, in the overall equation.

    I’m not saying you’re wrong about your opinion in that conclusion you’ve reached. What’s your estimate of when the next 100 happens and what the anomaly will be at that time in light of all the other factors in the process and the uncertainties involved?

  306. Steve Bloom:

    Re #s 302/3: That “large changes” phrase was just the writer’s attempt to avoid the reader interest-killing alternative of using the term “Arctic Oscillation” right up front and then immediately having to define it, while also avoiding saying “circulation” for a third time in the first paragraph. Of course just saying “circulation” or “large changes” doesn’t define Arctic Oscillation very well either, thus the confusion. The fact that the bit disconnecting the sea ice trend from the AO was buried way down in the body of the release was no help, but as I implied in another comment (that doesn’t seem to have appeared yet) a responsible journalist will look for wrinkles like that before going with the story. In particular, a responsible journalist would wonder why “large changes” was used if reference was being made to the sea ice trend.

  307. Raplh Smythe:

    Just so you know, my own ballpark on this (holding everything constant ratio-wise, % CO2 added per year, all non-C02 AGHG and O3 at the same rates, and predicting the future by the past) is a total of 800 ppmv and another +2.2 C within 33 years. That of course makes a lot of assumptions, which may or may not be warrented. Including the assumption my calculations are correct!

    So 100 is another +.53 C anomaly in about 8 years. It remains to be seen how correct the models are, what society and technology will do over the next 8 years, and how correct the assumptions have been.

    I still say focusing on anything other than reducing pollution as the goal and considering the methods to do so is rather spinning one’s wheels. But that’s just my opinion.

    Check it out in 2015.

  308. larry W:

    I have not had time to read all the above posts, but find them very interesting. As an engineer I like to look at the overall picture first. Global warming is much preferred to cooling because it increases all the components necessary for life: water, carbon dioxide, and heat. With world population increasing this is very important. With laws of thermodynamics, as more people generate more heat, does it not take a temperture rise to get it to leave earth?
    Getting a little more specific: The IPCC graph on Global Mean Temperature since 1850 leaves me with one impression other than the long term upward slope. Namely, the period 1910 to 1945 has at least the same upward slope as the last 25 years yet this is not mentioned with any significance. A downward and flat cooling period followed 1945. The Hadley Centre global mean temperature has been quite flat for the last ten years and the ocean temperatures seem flat also. What does your model say about this when the news media says we have more rapid heating?
    I hear no media talk about how the Clean Air Act is being applied around the world and what it will do to warming. One researcher said if we applied removal of sulfur from all world fossil fuels we can expect global warming equal to that expected from carbon dioxide. We certainly know sulfur dioxide’s influence better that CO2 given the cooling experience in the 70′s and various volcanos.
    Gore’s glacier data failed to say that glaciers started receeding in the early 1800′s and have continued at about the same long term rate. Where did the heat come from to cause the early glacier melt? Now excessive ocean level rise being blamed on ice melting. The total polar ten year survey using all best availabe melt calculated an amount equal to about 10% of ocean level rise and about 2 inches from melt per hundred years. Again not what the media publishes.
    Why am I sceptical? I have not heard one word of this data getting to the general public and all I see is all the scare tactics being thrown out and the news papers calling carbon dioxide a pollutant.
    Your point has been made about CO2 now do something significant about it and direct your billions of research dollars to solving the few nuclear power problems that the public has been scared to death about. The world has over 600 nuclear plants moving toward construction while the US finally gave one the green light to move forward. If we had put all the dollars that our wars are costing into building nuclear power we would shortly be free of foriegn oil and terriorism would fade to nothing. Oil went from $40 to $10 when we had the last plant building surge.
    Lastly, if your global warming group is truely worried about warming and not just forcing a cut back on our life style then lets put more work on putting reflective compounds into the upper atmosphere. The studies I have read said the cost is reasonable.
    I have gone on long enough to explain why many of my professional friends have lost faith based on the garbage we get in the news.
    If our nation is forced into the very expensive renewable enery we will become a second rate nation with the life style of the poor getting worse. Our state has already mandated that 15% of all new electrical capacity be from renewable, yet most have made that decision on what they read in the papers. Coal plants that can give the lowest cost power are being force to drop plans even if it uses the very expensive gasification route.
    Thanks for your time and comments would be gladly accepted.

  309. Chuck Booth:

    Re # 308 Larry W “I have gone on long enough to explain why many of my professional friends have lost faith based on the garbage we get in the news.”

    Then why not read what the scientific journals are saying (Science, Nature, Proc. of the Royal Society, Proc. of the NAS, etc), and the scientific organizations such as the NAS and the Royal Society, and the ICPP reports? They all have websites with free news updates, and some key journal articles are open access. Don’t rely on newspapers to filter the scientific news for you – they aren’t necessarily trying to mislead you, but their #1 objective is to sell newspapers.

  310. Hank Roberts:

    Quickly, just one reader here, reply to Larry’s many questions:

    > have not had time to read
    The “start here” link at the top of the page and “History” link under Science are good starts.

    > world population
    Direct energy production (waste heat) from all human activity is tiny compared to the increase in heat trapped by increasing greenhouse gases. Numbers are available, someone will recall what to search on.

    > slopes
    http://scienceblogs.com/stoat/2007/05/the_significance_of_5_year_tre.php

    You’ll also find discussion of the variation; old dirty coal before 1970; Clean Air Act limiting aerosols from US coal plants.

    > media/Clean Air Act
    That is only a US law, not copied in China or India where the new coal burning is increasing. At that more southerly latitude, aerosol/solar chemistry differs. This decade, background CO2 is higher, committed heating is already built in that the new dirty plants don’t overcome. Coal produces sulfate, acid rain, as well.

    >Gore failed
    What’s your source for your information, now, on this? Tell us what your source is and why you consider it reliable, and we may be able to comment on whether it has been reported correctly in the media. Which glacier data do you refer to? Which “total polar ten year survey” do you refer to?

    > Why am I skeptical?
    Everyone is. That’s why we’re here, all of us. The true believers are elsewhere pounding the drums for whatever they consider unassailable truth. Well, some visit occasionally. But they never have references to check.

    > Reflective compounds
    Try the Search box at the top of the page

    > Our nation … our state … lowest cost

    Cost includes those downwind, thus Clean Air Act and the recent Supreme Court decision, if you’re in the USA. External costs are starting to be accounted for. This makes the free market work. It bothers those who were profiting by externalizing costs.

    > even if it uses … gasification
    Gasification isn’t the same as sequestration or even control of output.

    What did someone (stockholders? regulators?) “force to drop plans” specifically? Pointer to actual story?

  311. Barton Paul Levenson:

    [[I’m not saying that the people writing here said that CO2 was the only variable. I’m saying it appears to me that in general it gets too much focus.]]

    No, it really doesn’t. The vast majority of global warming is due to increased CO2. If that increase had not happened, we would not be seeing significant global warming from about 1970 on.

  312. Barton Paul Levenson:

    [[Lastly, if your global warming group is truely worried about warming and not just forcing a cut back on our life style then lets put more work on putting reflective compounds into the upper atmosphere.]]

    With unknown side effects? And allowing the oceans to die through continued acidification? I have a better idea — reduce CO2 output in the first place.

  313. Gary Moran:

    Sorry if I’ve double posted, seemed to disappear:

    The hypothesis of AGW shouldn’t be couched in the words of certainty, and we should be careful of expensive policy decisions based on it. The evidence is primarily circumstantial: we are currently in a warming phase; while climate reconstructions favoured by RC show CWP to be unprecedented, other proxy studies show greater variability and there is a divergence problem between proxies and the current temperature series; paleoclimatology seems to show a reasonable split for the role of CO2 in the climate of the Phanerozoic; GCMs are useful tools in trying to understand what may be happening, but they are not reasonable evidence by themselves; surprisingly the underlying physics is far from certain, there seem to be multiple high level explanations of the atmospheric greenhouse effect, a reliance on a non physical concept termed “radiative balance”, and possible mis-applications of laws (e.g. Kirchhoff’s law of thermal radiation). The moderate (and I would guess predominate) sceptical view: that AGW is occuring, but that climate sensitivity will be at the low end of the spectrum, and will not be cataclysmic; is entirely reasonable.

    [Response: This is simply one fallacy after another. Current concerns about CO2 pre-date all proxy reconstructions and do not rely on anything being unprecedented. Please read - http://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/ for a background on all this. - gavin]

  314. James:

    Re #308: [Global warming is much preferred to cooling because it increases all the components necessary for life: water, carbon dioxide, and heat.]

    Actually that’s not so, if you consider all life. 3/4 of the Earth’s surface is water, and colder ocean waters are generally much more productive than tropical seas.

    Even on land, things aren’t nearly as simple as warmer=better. The Sahara is considerably warmer than the Yukon Delta, yet over the course of a year which do you think supports more life?

    Lastly, life tends to adapt to local conditions over the course of many thousands of years. Change those conditions quickly, in any way, and you’re going to disrupt the system.

  315. J.C.H.:

    steve bloom, others,

    I’m a lay person, so I can easily get off course on this stuff. The author of the study seems to me to be talking about Arctic Ocean circulation as being something distinct from (but related to) AO, which I understand to be a measurement of atmospheric pressure. Reading around the net, it seems some are discussing AO and Arctic Ocean circulation as identical things. I think I understand the relationship between the two, but not if they are one in the same thing.

    Does the report negate the following, which is from the same university:

    “The Arctic Oscillation has been in a primarily moderate to high phase during the last decade or more, and the only way to reproduce this tendency in the oscillation using a numerical climate model is if you include the observed increase in greenhouse gases in the model. …” – http://uwnews.org/article.asp?articleID=7070

    I guess I’m wrong, but I don’t interpret Morison’s quote, which he limits to the wet part of the Arctic, which I take him to mean specifically the Arctic Ocean water (liquid – he was using, among other things, ocean-bottom sensors), as applying specifically to anything about the Arctic climate system that is either frozen or gaseous. Am I totally off base on this? If so, please help me a out a bit.

  316. Rod B:

    re 306 (Steve): “…That “large changes” phrase was just the writer’s attempt to avoid the reader interest-killing alternative of using the term “Arctic Oscillation” ………. ”

    Which is what was explained to me a jillion posts ago, and what I accept, including the …..s above. I’m not going to skewer a writer for inadvertently screwing up an otherwise arcane technical nuance so as to make it readable. I’m just amused with the contortions and gyrations that others are going through to claim it was never written.

    I agree that journalists ought to verify stories, but it’s holding them up to the pristine ultimate level to say they should have bored into the body and between the lines and drawn their own expert conclusions to determine if the official “opening” statement was right or wrong. Seems like a unique and extreme standard. But I’m not really defending Fox. From their standpoint I don’t care.

  317. Raplh Smythe:

    Actually Barton, the vast majority of what is going on is due to carbon dioxide, ozone, and the other AGHG from fossil fuels (aborbing more IR et al), the feedbacks of water vapor in the process, pollution from fossil fuels (increasing the albedo of the atmosphere, interacting with clouds, being deposited on ice and decreasing its albedo, and being deposited in the oceans), and the clearing of areas that don’t normally absorb much heat in the ground (grasslands, forests, jungles) into ones that do (cities, farmland, roads). These are not separate issues and it doesn’t help every treating them like they are.

    Laboratory results showing what CO2 does, or models showing its part in climate are not the entire story. I don’t think it’s helpful to pay any attention to it alone. What creates CO2 (or CH4 or…) creates pollution, why deal with one of the AGHG and ignore the rest of it? To the “average person” ‘reducing pollution’ is probably a much better argument than ‘reducing carbon dioxide’.

    1. Focusing on and/or bickering over the role of 100 ppmv is counter-productive. Emotional points carry more weight.
    2. Logic is almost always beaten by emotion or perception.
    3. The details (CH4 or whatever) distract from the issue (slowing/halting/reversing detrimental climate change).
    4. 100 ppmv = +.7 anomaly is too simplistic in any case.
    5. The IPCC recognizes particulates and land use changes are an important consideration in this. We should too, and change our focus.

    I suggest interested parties look here for more factors to deal with in the system:

    http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/atmosphere/
    http://lwf.ncdc.noaa.gov/oa/climate/gases.html
    http://www.met.tamu.edu/class/old_atmo629/Week7%20Feedback%20Mech.ppt
    http://www.grida.no/climate/ipcc_tar/wg1/127.htm
    http://www.grida.no/climate/ipcc_tar/wg1/160.htm
    http://modis.gsfc.nasa.gov/data/atbd/atbd_mod03.pdf

    Radiative Forcing of Climate Change
    http://www.grida.no/climate/ipcc_tar/wg1/212.htm

    Anthropogenic aerosols scatter and absorb short-wave and long-wave radiation, thereby perturbing the energy budget of the Earth/atmosphere system and exerting a direct radiative forcing.

    It ain’t just CO2. It’s all I’m saying.

  318. Hank Roberts:

    Nobody thinks it’s just CO2.

    But we have to reduce CO2 regardless of climate because of ocean pH.

    Reducing CO2 is the “no regrets” strategy that helps everything else.
    There’s no way to reduce the other problems while leaving CO2 growing.

  319. Raplh Smythe:

    Hank, for somebody that says CO2 isn’t the only issue, you seem to focus on it quite a bit.

    Not important. How do you reduce CO2? By cutting the things people do to create extra. What is that? Primarily by burning fossil fuels, which also creates pollution.

    Reducing the burning of fossil fuels reduces “the other problems” while keeping CO2 from growing.

    We can’t attack CO2 without attacking the cause, burning of fossil fuels. Are you going to phrase it in “reduce CO2″ or “cut pollution”, that’s the issue here. I don’t care which you use, as long as it’s the one that will influence people more.

    The issue isn’t what the acid/alkaline ratio of the oceans is, or how fast the 2.4% of the water in polar ice caps and glaciers on Earth is melting, or what 1000 extra ppbv of methane would do, or what .03 to .04 of carbon dioxide would do.

  320. Hank Roberts:

    All those issues are of scientific concern. You want a discussion of framing and political tactics, I guess. I can’t help you here. Try anywhere in scienceblogs.com.

    “CO2 and other greenhouse gases” names the problem.
    http://www.pewclimate.org/global-warming-basics/

    Say “pollutants” and what’s the response?
    You can look this stuff up. For example

    http://www.google.com/search?q=tactics+for+controlling+pollution+by+greenhouse+gases

    You’ll start prolonged debates with arguments such as:
    pollutants aren’t legally controlled in their jurisdiction, or
    only new sources are subject to the laws and they’re grandfathered, or, well, this:
    http://news.independent.co.uk/world/americas/article3166414.ece

  321. Raplh Smythe:

    Yes, Hank. Good stuff. But I wouldn’t dare of trying to even argue the political minefields of the sources you’ve sited (if there’s anything more dicey than climate change, it’s politics and religion). I know there are a lot of “contrarians” out there, as in the topic of this post! But I’m just saying the science part has become a detail in the political arena and that’s where everything needs to focus. No matter how difficult the game, it has to be played at this point, not standing there in the huddle debating the next play while the other team scores.

  322. J.C.H.:

    “I’m just amused with the contortions and gyrations that others are going through to claim it was never written. …” – Rod B.

    Glad you were entertained.

    I had seen the report referred to on several blogs as proof global warming was not happening. There was a post from somebody talking about egg on the face, and gavin asked for a link, so I posted one. Prior to that moment, I didn’t know AO from BO.

    I have been reading about AO and ocean currents and ice movements and types of ice and ice extent, etc. all day and now understand what steve bloom is saying.

    I am curious if anybody has an opinion about the early AO indication and the bet.

  323. Hank Roberts:

    Plenty of science yet to do. Example:
    http://www.pnas.org/cgi/content/extract/104/47/18353

  324. Frank Warner:

    I’m a little confused about #7 on the list. The BBC says it’s irrelevant; this post says it’s a red herring; Al Gore made a big deal about it; an earlier post on RC supported Al Gore’s position.

    Recap: The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?

  325. Tim McDermott:

    re 308: Your point has been made about CO2 now do something significant about it and direct your billions of research dollars to solving the few nuclear power problems that the public has been scared to death about. (emphasis mine)

    It is always interesting to see where people think tax dollars are being spent. In five minutes with Google, I found that the FY 08 budgets for NASA earth sciences (which includes lots of non-climate stuff) is ~1.5B$. NOAA’s climate research is ~250M$. The entire NSF research budget is ~5B$.

    The DOE research budget (where non-military nuke research lives) is ~4B$.

    Nuclear energy has always had a pretty fat budget.

  326. Hank Roberts:

    #7 — here: http://illconsidered.blogspot.com/2006/02/co2-lags-not-leads.html
    http://illconsidered.blogspot.com/2006/03/geological-history-does-not-support.html

  327. wayne davidson:

    #322, The bet is trivia. of only amusement value, its fun, like anything from Fox news is funny, but AGW subject is very serious. Anyone claiming the great melt of 2007 as just an anomaly, does not understand, perhaps not aware, of present Arctic Ocean ice coverage laced with thousands upon thousands of extra unfamiliar leads, amongst a huge area of thin ice. This is truly unknown territory, begging the question, how could this Ice cap ever return to normal? Certainly not in one year. Momentum is for melting, and some forget big time, the great melt occurred during a solar minima, it gets warmer from here folks.

    What I find intriguing is the apparent similarity with pressure systems, some call it AO, , but why would they be similar? Given tremendous temperature changes, it is fascinating that they are familiar, leaving to the very possible event , as happening right now again, “warmer winds from the North”, Arctic Oscillations at +20 C….

  328. Timothy Chase:

    Frank Warner (#324) wrote:

    I’m a little confused about #7 on the list. The BBC says it’s irrelevant; this post says it’s a red herring; Al Gore made a big deal about it; an earlier post on RC supported Al Gore’s position.

    Recap: The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?

    Let’s take a look:

    7. A CARBON DIOXIDE RISE HAS ALWAYS COME AFTER A TEMPERATURE INCREASE NOT BEFORE

    Sceptic:
    Ice-cores dating back nearly one million years show a pattern of temperature and CO2 rise at roughly 100,000-year intervals. But the CO2 rise has always come after the temperature rise, not before, presumably as warmer temperatures have liberated the gas from oceans.

    Counter:
    This is largely true, but largely irrelevant. Ancient ice-cores do show CO2 rising after temperature by a few hundred years – a timescale associated with the ocean response to atmospheric changes mainly driven by wobbles in the Earth’s orbit. However, the situation today is dramatically different. The extra CO2 in the atmosphere (35% increase over pre-industrial levels) is from human emissions. Levels are higher than have been seen in 650,000 years of ice-core records, and are possibly higher than any time since three million years ago.

    Climate scepticism: The top 10
    Last Updated: Monday, 12 November 2007, 11:55 GMT
    http://news.bbc.co.uk/2/hi/in_depth/629/629/7074601.stm

    I think that particular response could have been clearer.

    The main point is that scientists do not argue that the relationship between temperature and atmospheric carbon dioxide is one-way but instead that there exists positive feedback between the temperature and atmospheric carbon dioxide.

    *

    Raise the temperature and the capacity of the ocean to absorb carbon dioxide or even hold onto the carbon dioxide which it has is diminished – like soda which becomes warm and loses its fizz. Raise the level of carbon dioxide and you diminish the rate at which thermal radiation is lost from the climate system so that the only way that the amount being radiated from the system can equal the amount entering the system is for the climate system to become warmer.

    When the temperature goes up first due to increased solar radiation, the consequent rising level of carbon dioxide will amplify the initial forcing, causing the temperatures to go still higher. When the carbon dioxide goes up first, the rising temperature will result in more carbon dioxide entering the atmosphere — pushing the temperatures up further. It doesn’t really matter where the initial forcing which disturbs the system comes from so much as the fact that there exists positive feedback once the system becomes disturbed — until the system finds the new equilibrium.

    *

    Moreover, there are times in the earth’s history in which a change in the level of carbon dioxide came first. Perhaps the best example is from 251 million years ago with the eruption of a siberian supervolcano. This raised the level of carbon dioxide in the atmosphere to around 3000 ppm, driving up the temperatures, and the result was the greatest extinction found in the paleoclimate record, wiping out perhaps 96% of all marine species and 70% of all land species.

    This is what is known as the Permian-Triassic Extinction, but sometimes it will simply be refered to as the Great Dying. For a while the dominant life form on land appears to have been fungus. Even among surviving species, generally more than 99% of their populations were wiped out. The biosphere didn’t really begin to recover for several million years.

    *

    Incidentally, you will notice that my explanation was a great deal longer than any of the explanations that were given in that piece. It can be difficult to explain things economically without sometimes losing important details.

  329. Barton Paul Levenson:

    Frank Warner writes:

    [[The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?]]

    In a natural deglaciation, temperature rises first and CO2 follows, but CO2, being a greenhouse gas, raises the temperature further. We are not seeing that now. For the past 200 years or so CO2 has led temperature. Two different processes are involved. In a natural deglaciation, the CO2 is coming primarily from the ocean. In the present warming, it’s coming primarily from fossil fuels.

    The fact that warming in the past has been natural does not mean it has to be natural now. That would be like saying, “people have died naturally for thousands of years, so this guy with the twenty bullet holes in him must have died naturally.”

  330. Rod B:

    J.C.H., “….I had seen the report referred to on several blogs as proof global warming was not happening.”

    Therein lies the rub. Clearly many skeptics will not take my position but instead latch on to the molehill and make a mountain out of it. I understand that and the dilemma it causes. But I can’t help it; nor does it change what was written and what a very natural and common interpretation of the writing is. Instead of the contortions to change what was written, which makes you protagonists look silly, you should just claim it for what it is, tell the rabid set of us skeptics to stuff it, and then move on.

  331. dean:

    Re #271-273

    While you’ve given me good resources to CO2 increases (which i do not question in any way), I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate? Solar forcing tracks amazingly well over the last 200 years and if the earth is now just equalizing from the peak solar forcing of the 50s, it’s not tough at all to extrapolate that this is what’s causing the temperature rise.

    it certainly matches the 400 year trend much better than CO2 levels.

  332. Rod B:

    Raplh (??) and Hank, this comment question might go against my overall position, but assuming Raplh’s contention is correct (all things ought to be addressed), doesn’t the practicality say to focus on CO2 since that’s what we seem to know more about its causes and fixes. Even as poor (IMO) as that is, isn’t it more than we know about methane, ozone, etc., at least in the GW scenario?

  333. Jim Eager:

    Re Frank Warner @ 324: “The Ice records show CO2 lags temperature in geological history. How does this make the case of future increases of CO2 causing temperature rise…or is it irrelevant?”

    This is one of the most common questions/points raised by both skeptics and those just seeking to understand the mechanism of climate change alike.

    In the case of those who simply don’t yet understand that CO2 is a demonstrated greenhouse gas that can increase temperature both as a feedback and as a direct forcing, simple clear explanations like those given by Hank, Timothy and Barton should help clear up any misunderstanding, along with pointers to sources like Spencer Weart’s The Discovery of Global Warming @ http://www.aip.org/history/climate/index.html

    In the case of skeptics, however, the lag in the glacial record between temperature and CO2 is thrown out as a challenge, as if they were just playing a game of ‘gotcha’ and the lag negates all that we know about the physics of CO2 as a greenhouse gas. The fact that CO2 can act as a positive feedback and raise temperature further either never enters their mind, or is deliberately ignored, since it hardly supports their “gotcha.” The only thing one can do in that case is point out the error in their argument in hopes of preventing them from leading others astray.

  334. Jim Eager:

    Re dean @ 331: “I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate?”

    But it’s not, as has been discussed here many, many times in numerous posts and comment threads. See here:
    http://www.realclimate.org/index.php/archives/category/climate-science/sun-earth-connections/langswitch_lang/sp

  335. Paul:

    re # 308 “Terriorism would fade to nothing” My Westie wants to know why SHE is being blamed now…

  336. Timothy Chase:

    dean (#331) wrote:

    Re #271-273 [Ray Ladbury and Hank Roberts]

    While you’ve given me good resources to CO2 increases (which i do not question in any way), I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate? Solar forcing tracks amazingly well over the last 200 years and if the earth is now just equalizing from the peak solar forcing of the 50s, it’s not tough at all to extrapolate that this is what’s causing the temperature rise.

    it certainly matches the 400 year trend much better than CO2 levels.

    Actually, best estimates given by the Nasa GISS, it would appear that forcing due to well-mixed greenhouse gases have been a better match for temperature than solar forcing virtually every year since 1880 — with the one exception being that of 1881.

    Please see the graphs at:

    Forcings in GISS Climate Model
    http://data.giss.nasa.gov/modelforce

    … as well as the data at:

    Global Mean Effective Forcing (W/m2)
    http://data.giss.nasa.gov/modelforce/RadF.txt

    … and of course the technical papers which are linked to at the bottom of the first.

    *

    Well-mixed greenhouse gases would be principally carbon dioxide, methane and nitrous oxide — in that order. Nasa is of course omitting water vapor since it is a feedback which amplifies the effects of the well-mixed greenhouse gases, not a forcing. Finally, with the leveling off of methane and aerosols in recent years, carbon dioxide has been a better match for temperature since the late 1970s. Moreover, solar forcing has been essentially flat since the early 1950s.

    With the diminishing effects of reflective aerosols since the 1970s, one can most clearly see the weakness of the case for solar forcing being the primary determinant of the rise in temperature during the twentieth century. Since the 1970s, temperatures have accelerated. According to Tamino’s statistical analysis, even once one accounts for autocorrelation, the acceleration of global temperature in the past 15 years relative to the preceding 15 has been statistically significant.

    Now you have invoked latent warming, resulting from the increase in solar forcing prior to the 1950s. However, latent warming necessarily decelerates over time, falling off roughly as an exponential function of time, whereas the temperature increase has accelerated. As such, in logic, the latency of solar forcing cannot be invoked.

    *

    Finally, I appreciate the fact that you speak of “forcing” which belongs to a conceptual framework in which rather than attempting to reduce “the cause” of trends in temperature to a single factor, we recognize the existence of multiple causal factors. However, I am then puzzled by the fact that you then attempt to reduce “the cause” of trends in temperature to the single factor of solar forcing. I find this especially puzzling when you require trends in carbon dioxide over the past four centuries (thus including the 1600s) to be a better match for temperature before carbon dioxide can (in your view) be regarded as a causal factor.

    Industrialization became a factor only within the past two centuries, and became a major factor only with the consequent rise in the gobal population — which happened primarily during the twentieth century. The rise in the level of carbon dioxide, and its consequent dominance as the primary forcing driving the rise in global temperature was largely a function of this industrialization.

    PS

    If you want people to realize that you are responding to them, it might be good for you to respond a little sooner. Either that or actually include their names in the post itself. I strongly doubt that Ray Ladbury and Hank Roberts still remember the actual numbers of their posts — particularly after a little more than three days after the last of these posts.

  337. Chuck Booth:

    This should be a more authoritative rebuttal of the AGW skeptics’ talking points:

    http://www.royalsoc.ac.uk/page.asp?id=6229

    Climate Change Controversies – A simple guide

    The Royal Society has produced this overview of the current state of scientific understanding of climate change to help non-experts better understand some of the debates in this complex area of science.

    This is not intended to provide exhaustive answers to every contentious argument that has been put forward by those who seek to distort and undermine the science of climate change and deny the seriousness of the potential consequences of global warming. Instead, the Society – as the UK’s national academy of science – responds here to eight key arguments that are currently in circulation by setting out, in simple terms, where the weight of scientific evidence lies…

    [If someone has already posted this link, I apologize for overlooking it]

  338. Ray Ladbury:

    Dean, re: #331, If you had bothered to read Solanki’s work on solar forcing, you would have found that it is totally inadequate to explain the current warming trend.
    You also state: “Solar forcing tracks amazingly well over the last 200 years and if the earth is now just equalizing from the peak solar forcing of the 50s, it’s not tough at all to extrapolate that this is what’s causing the temperature rise.”
    Perhaps it is “not tough at all” if one is ignorant of the science or if one is willing to abandon conservation of energy. Since that is not the case for me, I find it quite tough indeed. Maybe you can help me. First, as Timothy has pointed out, insolation by itself is inadequate as a source of energy. Where did all the energy come from? Second, if Earth is “now just equalizing,” that would presume that all the energy now heating the atmosphere, surface and oceans was hidden somewhere for the last 50 years, and that this reservoir must now be cooling. Just where is this reservoir of heat? How did it remain undetected? Why did it take 50 years to “equalize”?
    Look, Dean, you can wave your hands until you levitate, or you can go actually work through the science and see that it is credible. If you have questions, the moderators (who are experts in the field) are good about answering them. If you don’t have the physics background for this, or if you don’t want to invest this much effort, then you are stuck at some point relying on authority. And if you are going to rely on authority, why in the hell would you take that of nonexperts when the experts are backed up by endorsements for every scientific professional society that has taken a position at all?

  339. dean:

    Timothy (#337)

    I apologize for the slowness in posting my response. But sometimes life gets in the way of non-critical intellectual discussions (and since this is more of a hobby than a job for me, it is non-critical).

    I still disagree that GHG shows a better match for temperatures over the last few hundred years. While you mention the work Tamino did on GISS, if you use HadCRU data, your result is debatable. Specifically, the HadCRU data shows that the warming in the early 20th century was equal to what we’re seeing today. It’s commonly accepted here that GHG weren’t the cause of that warming period.

    It’s also accepted that aerosols caused the cooling from the 50s to the 70s.

    So what does this mean to me? well, i see the most likely scenario playing like this: the sun was relatively quiet throughout the 16th & early 17th centuries. The as it started to come out of it’s quiet phase, the temperature started to rise, albeit with a significant lag behind the solar forcing (up to 50 years). the solar forcing undulated for about 150 years at levels much lower than today’s value and concurrently, the earth warmed some and cooled some. Then in the first half of the 20th century, the sun got serious. That resulted in the steep temperature rise of the first half of the century.

    But then something happened… something man-made. Aerosols. This ‘artifically’ cooled the earth by reflecting away the solar heating (do i have that right? aerosols increase albedo?). but man figured out aerosols were a problem so man eliminated them and now the effect of a really active sun is once again being felt. hence, we see a major temperature rise even tho we don’t see the corresponding increase in solar output.

    Mayby this thought experiment will help understand my point: imagine that your oven is set to 150 degrees F. you take a pan of tap water (room temp of about 75 degrees) and put it in the oven. you start measuring the temperature of the water. after 5 minutes, you pull the pan out and put it in the freezer for 3 minutes. Then back into the oven. The resulting temperature vs time plot will look much like the 20th century temperature plot. It will start with a strong temperature rise (initial entry into the oven), followed by a slight decline (the freezer), followed by an even stronger temperature rise. It’s clear that the first entry didn’t get the water to equilibrium, so the second temperature rise ends at a higher point.

    Why does this not match the data?

  340. John Finn:

    Gavin

    In response to an earlier post (#239) you claim that the G&T paper is “garbage”. I’ve now read the paper (twice) and checked out the ‘rebuttal’ links to which you refer. While it’s probably fair to say that some of the points made by G&T are open to debate I wouldn’t describe them as garbage. I am intrigued, though, by an issue raised in the paper. That is, the discrepancy between the average amount of solar energy (240 w/m2) received by the “non-greenhouse” earth and the properly calculated (rather than the assumed –18 deg C) effective temperature.

    The generally accepted effective temperature of 255K (-18 deg C) would, I suppose, be correct if the earth were a uniform flat disk but it is clearly not correct for a sphere. I always assumed any difference would be relatively small, but G&T show, by integrating temperatures over a static globe, that the effective temperature is –129 deg C. This does seem to raise some doubts about the greenhouse theory which says that the greenhouse effect is responsible for raising the average global temperature by 33 degrees.

    [Response: But this kind of thing is exactly why G&T is garbage. The standard calculation for the effective temperature explicitly takes into account the difference between the disk and the sphere (the factor of '4' which is the ratio of the different surface area). That is a global mean calculation of course, but the difference using a realistic distribution of surface temperature is very similar (that is actually what GCMs calculate). However, G&T's bizarre -129 comes from assuming a local instantaneous radiative balance at every point on the globe and then averaging the the resulting temperatures. Since half the planet is always dark, the local radiative temperature is 0 Kelvin (!) there - hardly a realistic calculation for the Earth. This neglects both the effects of thermal inertia and heat transports which are correctly integrated into the standard global mean calculation. Thus with much more mathematics than is necessary (they have a full derivation of the ratio of the surface areas of the sphere and disk - woo hoo), G&T manage to come up with a completely irrelevant calculation that is supposed to overturn all conventional thinking. That is simply garbage. - gavin]

  341. James:

    Re #338: [And if you are going to rely on authority, why in the hell would you take that of nonexperts when the experts are backed up by endorsements for every scientific professional society that has taken a position at all?]

    Ray, I realize your question is rhetorical, but maybe some people need the answer spelled out: Because the experts aren’t giving them the answer they want :-)

  342. Barton Paul Levenson:

    dean writes:

    [[ I still question why CO2 is the culprit this time when solar forcing seems a much more obvious candidate?]]

    Because solar forcing isn’t a much more obvious candidate. The present global warming can’t be caused by the sun. There are four major reasons for this.

    1. The solar constant has not increased appreciably for 50 years. We’ve been measuring it from satellites like Nimbus 6 and -7 and the Solar Maximum Mission.

    2. Increased sunlight would heat the stratosphere first. But we’re seeing stratospheric cooling. Partly this is due to ozone depletion, but the increase in greenhouse gases accounts for the rest of the effect.

    3. Increased sunlight would heat the equator more than the poles (Lambert’s cosine law). Instead we’re seeing polar amplification, which, again, was predicted by the climate models.

    4. Increased sunlight would raise daytime temperatures more than nighttime temperatures (obviously). But nighttime temperatures are increasing faster than daytime. This makes sense if increased atmospheric opacity from higher greenhouse gases is holding in heat at night.

  343. Jim Galasyn:

    Thanks to Barton in 342 for his cogent and concise refutation of the solar forcing argument.

  344. Phil. Felton:

    Re Gavin’s response to #340: The assumption that G&T make works fairly well for the sunlit surface of the moon (i.e a Lambertian profile) which has no atmosphere at all, and has an ~28 day rotation period. Mars with it’s much thinner atmosphere doesn’t have a Lambertian profile.
    BRIGHTNESS TEMPERATURES OF THE LUNAR SURFACE: S. L. Lawson and B. M. Jakosky, Lunar and Planetary Science XXX

    [Response: Like I said, relevance to Earth = 0. - gavin]

  345. Hank Roberts:

    Hey, speaking of experts not giving the answers they want, the inimitable Benny Peiser just featured this in his CCNet email:

    “Craig Loehle has published a study in [Energy & Environment] indicating that trees rings are not reliable for determining past temperatures. Loehle focused on the Medieval Warm Period (MWP) (1000 – 1400) which is not shown in tree rings….”

    Yep. We know it happened, so, since the trees didn’t record it, that proves the tree rings are wrong.

    Oy. Another E&E headbanger.

  346. Ralph Smythe:

    Rod B, #332, yes. I can’t even spell my own name correctly, why would anyone listen to me! :)

    Seriously though, not accusing anyone of focusing on CO2, but overall, it is unimportant to the discussion, in and of itself. A simplistic statement like “Rising CO2 levels since the start of the industrial era is causing a dangerous rise in average temperatures.” makes most folks go glassy eyed, I’d think. You have to know your audience. If somebody knows that CO2 is half the AGHG component, and that the cause of AGHG is fossil fuels, they might wonder why we’re not talking about reducing the burning of fossil fuels in the context of all AGHG and pollution instead of one of the AGHG. (And don’t forget land use changes.)

    Does any person not familiar with either the science or the contentiousness of climate change have their emotional buttons pushed by phrasing it in terms of carbon dioxide? Those that take a look deeper into this might question why .0003 to .0004 (.0000008 a year) of CO2 is important, if a 5.6 millidegrees C a year is a big deal, if one causes the other, or if the current trend will continue. I’m a proponent of “what if” and I certainly think these are issues at least to consider. My entire point, consider what conclusions that others not well involved might come to.

    I’m not arguing these things are not important, or asking about the science. I’m questioning how the issue is put forth.

    So, no, no matter how much we know about how CO2 acts, regardless if in practice, theory, models, or laboratory experiements, it shouldn’t be either the focus or even a topic. If the cause/effect is “CO2/temperature” then the more important relationship is “fossil fuels/CO2″. Or more accurately, “fossil fuels = AGHG + pollution”, or “fossil fuels + land-use changes = warming”.

  347. Tim McDermott:

    Ralph (346),

    You seem to be arguing in circles, and not very rigorous circles at that. You don’t want AGW to be presented as a CO2 problem, but as a fossil fuel (and a some other things) problem. The trouble with your approach is that you have factored out two sources of CO2 and want to feature them as the causes of AGW. Land use is part of AGW because when we convert forest to farmland, the CO2 that the forest held in the soil gets released. You forgot cement production, which is a huge source of CO2. As we reduce the release of fossil carbon, most of the other GHGs are going to be reduced as well.

    And I think that I don’t agree with you that “fossil fuels” is less eye-glazing than “carbon dioxide.” The reason people’s eyes glaze over is they think the entire subject is unimportant, and dull. Even high school drop-outs will pay attention to discussions of CO2 when they start to understand that it threatens their children and grandchildren. The entire denialist community is dedicated to putting that understanding off as long as possible.

  348. dean:

    Re 342

    Point by point…

    1. so what. If we weren’t at thermal equilibrium due to solar forcing in 1950, then we had not reached the temperature the sun was trying to bake us to. After the rise in the 1910-1945, the sun didn’t shut off. so the temperature should have stabilized at a new temperature (with the appropriate lag due to inertia of the system). but it didn’t. It cooled. Why? because the aerosols didn’t allow the energy from the sun to be absorbed. But man realized that aerosols were pollutants so we removed them. now we have an earth that’s returning to equilibrium. But it’s not the temperature in the 50s, its higher because we never reached equilibrium from the early 20th century solar forcing.

    Tim (in post 336) said that the latent heat drops off over time. I agree. but where this is a problem is with the temperature data between 1940 and 1950. The solar forcing that drove temperature up in the early century continued but the temperature suddenly dropped. why? because of aerosols. this pushed the earth farther from the equilibrium temperature and therefore the speed of rise increased once the aerosols were removed (which, by the way, was over time and not instantaneous)

    2. let me think about this one…

    3. But what doesn’t match here is that the poles (plural) aren’t warming. Only the north pole is. And the fabled “northwest passage” has been open before only to close back. there is nothing new in what we’re seeing. It’s all happened before (in recent recorded history) and most likely will happen again. The north pole warming and the south pole not warming goes against the climatic models, doesn’t it? not only that, none of the models predicted the massive melt-off this year. So something other than what’s in the models caused it (or if it’s in the models, then it’s not accurately modeled).

    4. But aren’t there questions as to the accuracy of that data? specifically, the weather station locations in urban areas (and don’t try to tell me that cities aren’t heat islands… ok, you can try, but i will not believe that because it just doesn’t make sense … I’ve leaned up against enough buildings after the sun’s set only to feel the bricks still radiating heat).

  349. Ray Ladbury:

    Ralph Smythe, How would you suggest the argument be couched if not in terms of the sound science? Look, cheap fuels have distorted the global economy to an absolutely absurd degree. Here in Maryland, I can buy tropical fruits like durian, pineapple, mango and papaya (not exactly compact) more cheaply than I can buy locally produced apples and pears! That would argue that there are hidden costs not being paid by the consumer. Do you expect people to rally around such an economic argument? All I can say is that if humans are too stupid to understand the science, they’d better get a helluva lot smarter quickly.

  350. Timothy Chase:

    dean (#339) wrote:

    Timothy (#336)

    I apologize for the slowness in posting my response. But sometimes life gets in the way of non-critical intellectual discussions (and since this is more of a hobby than a job for me, it is non-critical).

    I still disagree that GHG shows a better match for temperatures over the last few hundred years.

    As I pointed out (336) it is invalid to expect CO2 to be more closely correlated with global temperature than solar variability prior to the industrial revolution. You may be attempting to reduce the trends in temperature to either solar variability and aerosols or carbon dioxide, but climatologists acknowledge the existence of several forcings — and with the cummulative effects of industialization, prior to 1880, solar variability tended to be a greater forcing than greenhouse gases, but not the only forcing. Relative to 1880, the only year in which solar variability was a greater forcing than greenhouse gases was 1881.

    dean (#339) wrote:

    While you mention the work Tamino did on GISS, if you use HadCRU data, your result is debatable. Specifically, the HadCRU data shows that the warming in the early 20th century was equal to what we’re seeing today.

    If you use HadCRU then the past fifteen haven’t shown a noticable increase. However, HadCRU specifically omits the arctic. GISS does not. As such, GISS is a more accurate assessment of the global average temperature — if one is specifically looking for the global average.

    dean (#339) wrote:

    It’s commonly accepted here that GHG weren’t the cause of that warming period.

    Actually it is commonly accepted that carbon dioxide wasn’t the main driver of the earlier warming period. Solar variability was stronger in the earlier half of the twentieth century than carbon dioxide. However, greenhouse gasses (or if you wish, simply carbon dioxide and methane taken together) had a greater forcing than solar variability. And according to the GISS data that I supplied you with in 336, they have been since 1882 relative to 1880 — as I indicated earlier.

    dean (#339) wrote:

    It’s also accepted that aerosols caused the cooling from the 50s to the 70s.

    Actually there were only six years of statistically significant global cooling from 1945-1951.

    Please see:

    Hemispheres
    August 17, 2007
    http://tamino.wordpress.com/2007/08/17/hemispheres

    dean (#339) wrote:

    So what does this mean to me? well, i see the most likely scenario playing like this: the sun was relatively quiet throughout the 16th & early 17th centuries. The as it started to come out of it’s quiet phase, the temperature started to rise, albeit with a significant lag behind the solar forcing (up to 50 years). the solar forcing undulated for about 150 years at levels much lower than today’s value and concurrently, the earth warmed some and cooled some. Then in the first half of the 20th century, the sun got serious. That resulted in the steep temperature rise of the first half of the century.

    There would be no lag of 50 years. As I have stated in 336, latent warming is strongest at the time of the increase in forcing and declines after that asymptotically over time — roughly as an exponential function of time.

    dean (#339) wrote:

    But then something happened… something man-made. Aerosols. This ‘artifically’ cooled the earth by reflecting away the solar heating (do i have that right? aerosols increase albedo?). but man figured out aerosols were a problem so man eliminated them and now the effect of a really active sun is once again being felt. hence, we see a major temperature rise even tho we don’t see the corresponding increase in solar output.

    In essence, reflective aerosols increase the albedo, but normally I believe the two are distinguished for conceptual reasons.

    dean (#339) wrote:

    Mayby this thought experiment will help understand my point: imagine that your oven is set to 150 degrees F. you take a pan of tap water (room temp of about 75 degrees) and put it in the oven. you start measuring the temperature of the water. after 5 minutes, you pull the pan out and put it in the freezer for 3 minutes. Then back into the oven. The resulting temperature vs time plot will look much like the 20th century temperature plot. It will start with a strong temperature rise (initial entry into the oven), followed by a slight decline (the freezer), followed by an even stronger temperature rise. It’s clear that the first entry didn’t get the water to equilibrium, so the second temperature rise ends at a higher point.

    Why does this not match the data?

    Offhand I can think of six reasons…

    First, we know that without the greenhouse effect, the average temperature of the earth would be -18 C rather than 15 C as a matter of simple physics. Clearly the greenhouse effect exists. As such, your single factor analysis (or two-factor, since you admit the role of reflective aerosols) is simply invalid.

    Second, the reason why we conclude that carbon dioxide is the primary forcing in the recent rise in temperature isn’t simply one of correlation. We know from spectral analysis that it absorbs and emits thermal radiation. We know its distribution in the atmosopheric column.

    We can measure it’s emissions at different altitudes. We can image those emissions from satellites at a variety of altitudes, measure it from planes, balloons and the surface. We have spectral measurements of atmospheric constituents at over a million different wavelengths. As such, the forcing due to carbon dioxide is well-known. We can do the same with solar variability, and while the exact effects of aerosols are more uncertain given their diversity and distribution, no such difficulties exist in the case of solar variability or carbon dioxide.

    As such, for the forcings due to solar variability and carbon dioxide are given with considerable accuracy by the GISS data I referred you to:

    http://data.giss.nasa.gov/modelforce/RadF.txt

    In watts per square meter, forcing due to well-mixed greenhouse gasses relative to 1880 was 1.6053 in 1978 and was 2.7487 in 2003. Given the leveling off of methane, the good majority of the difference between the two years is carbon dioxide. Forcing due to solar variability relative to 1880 was 0.2232 in 1978 and was 0.2233 in 2003. Not much of a difference between the two years, is there? Clearly, relative to 1880, the increase in forcing due to well-mixed greenhouse gasses (principally carbon dioxide and methane) has exceeded that of solar variability.

    Third, there is the fact that with statistical analysis, we can directly measure the greenhouse effect of water vapor and the fact that above 85 F in the tropics, and moreover, showe that there exists a super greenhouse under clear sky conditions where downwelling thermal radiation due to water vapor increases more rapidly than upwelling thermal radiation relative to temperature.

    I quote:

    At sea surface temperatures (SSTs) larger than 300 Kelvin, the clear sky water vapor greenhouse effect was found to increase with SST at a rate of 13 to 15 watts per square meter per Kelvin. Satellite measurements of infrared radiances and SSTs indicate that almost 52 percent of the tropical oceans between 20 N and 20 S are affected during all seasons….

    Satellite studies (8–10) have found that for clear skies and SSTs above 298 K, the spatial variation of Ga with SST, dGa/d(SST), exceeds the rate of increase of sea surface emission, ds(SST)4/d(SST) = 4σ(SST)3. For a tropical SST of 300 K, 4σ(SST)3 ~ 6.1 W m-2 K-1. This effect, termed the “super greenhouse effect” (11), occurs in both hemispheres during all seasons. It is also observed for interannual variations of Ga with SST during the El Nino in the tropical Pacific (12). Observations in the tropical Atlantic ocean (11) show that the clear sky downwelling infrared flux incident on the surface (Fa-) also increases faster than the surface emission with increasing SST. The net result is further warming of the surface, which in turn induces additional heating of the atmosphere column above.

    Direct radiometric observations of the water vapor greenhouse effect over the equatorial Pacific Ocean
    F.P.J. Valero, W.D. Collins, P. Pilewskie, A. Bucholtz, and P.J. Flatau
    Science, 274(5307), 1773-1776, 21 March 1997

    If one admits the existence of a greenhouse effect due to water vapor, one must admit a greenhouse effect due to carbon dioxide since the physical principles involved are the same — and the actual spectra themselves are virtually derivable from quantum mechanics. And given spectral analysis of carbon dioxide, we know that as you increase the levels of carbon dioxide, you increase the downwelling thermal radiation.

    Fourth, there is the diurnal temperature difference which has been on the whole decreasing roughly since 1950. This cannot be explained by solar variability. It can be explained by the diminished ability of the climate system to lose energy by means of thermal radiation.

    Please see:

    http://img37.picoodle.com/img/img37/5/11/23/timothychase/f_diurnalzugsm_a6bddcb.jpg

    Fifth, given an enhanced greenhouse effect, we would expect the trend in summer temperatures to be greater than the trend in winter temperatures. With the enhanced greenhouse effect we expect the opposite. The trend in winter temperatures has been greater over the twentieth century.

    Sixth, increased solar variability would result in the warming of the stratosphere. Given the greenhouse effect we would expect the stratosphere to have a cooling trend. The latter is the case.

    Please see:
    HadAT: globally gridded radiosonde temperature anomalies from 1958 to present
    http://hadobs.metoffice.com/hadat/

    … and especially:

    Frequently used HadAT graphics
    http://hadobs.metoffice.com/hadat/images.html

    I hope this helps…

  351. Jim Eager:

    Re Jim Galasyn @ 343: “Thanks to Barton in 342 for his cogent and concise refutation of the solar forcing argument.”

    Never the less, dean persists in tilting at this particular windmill in not one, but two different threads at the same time.

  352. Hank Roberts:

    Re “Fifth” — I think a word’s wrong or lost there.

  353. Timothy Chase:

    Hank Roberts (#352) wrote:

    Re “Fifth” — I think a word’s wrong or lost there.

    Arrgh!!

    Thank you, Hank.

    In 350 I should have written:

    Fifth, if it were due to solar variability, we would expect the trend in summer temperatures to be greater than the trend in winter temperatures. With the enhanced greenhouse effect we expect the opposite. The trend in winter temperatures has been greater over the twentieth century.

    I do that sort of thing too often… Oh well. I will keep working on it. Rereading before I hit the “Postt”.

  354. Timothy Chase:

    Barton Paul Levenson (#342) wrote:

    2. Increased sunlight would heat the stratosphere first. But we’re seeing stratospheric cooling. Partly this is due to ozone depletion, but the increase in greenhouse gases accounts for the rest of the effect.

    It is worth pointing out that the physical principles behind ozone depletion resulting in the cooling of the stratosphere is still a matter of absorption and emission — like the warming of the surface by the absorption of thermal radiation by the greenhouse gasses in the troposphere and emission of thermal backradiation to the surface. Where ozone has its greatest effect, it warms the atmosphere due to the absorption of ultraviolet radiation — before that radiation gets the chance to reach the surface and is converted into longwave radiation.

    If he admits to ozone having a greenhouse effect in the stratosphere, then he has to admit that carbon dioxide will have a greenhouse effect in the troposphere. Likewise, without amplification by greenhouse gasses (primarily water vapor, but carbon dioxide as well), solar variability would not be able to account for much of the swings in temperature that we find in the paleoclimate record that resulted from variations in the earth’s orbit.

    Anyway, if people want to see the effects of the different greenhouse gases in terms of the cooling or warming of the atmosphere at various altitudes, I would suggest:

    Radiation & Climate: Major Projects
    Line-by-line calculation of atmospheric fluxes and cooling rates 2
    http://www.aer.com/scienceResearch/rc/m-proj/abstracts/rc.clrt2.html

    They will notice that the direct effect of carbon dioxide is principally one of cooling the atmosphere, not warming it. This is because the radiation which is emitted by carbon dioxide has on the balance the effect of cooling the atmosphere (due to emitting backradiation to the surface and thermal radiation to space) but warming the surface — with the troposphere being warmed principally by thermals and evapotranspiration.

    For a basic energy balance diagram, people might check out:

    The Energy Balance and Natural Climate Variations
    http://www.cara.psu.edu/climate/climatechangeprimer-pr4.asp

  355. Timothy Chase:

    dean (#348) wrote in response to Barton pointing out that solar variability has been flat for more than fifty years:

    Re 342
    1. so what. If we weren’t at thermal equilibrium due to solar forcing in 1950, then we had not reached the temperature the sun was trying to bake us to. After the rise in the 1910-1945, the sun didn’t shut off. so the temperature should have stabilized at a new temperature (with the appropriate lag due to inertia of the system). but it didn’t. It cooled. Why? because the aerosols didn’t allow the energy from the sun to be absorbed. But man realized that aerosols were pollutants so we removed them. now we have an earth that’s returning to equilibrium. But it’s not the temperature in the 50s, its higher because we never reached equilibrium from the early 20th century solar forcing…

    Given the fact that land temperatures increased by nearly one degree celsius (0.8 C) from 1960 to 2000, for solar brightening to be responsible for the rise in temperature after the “flat period” from 1952 to 1975 during which aerosols were a major factor, it would have to be greater than the solar dimming within the same 1960-2000 period. However, solar dimming outweighed solar brightening over this period.

    Please see:

    Recent solar brightening cannot supersede the greenhouse effect as main cause of global warming, since land temperatures increased by 0.8 C from 1960 to 2000, even though solar brightening did not fully outweigh solar dimming within this period.

    Impact of global dimming and brightening on global warming
    Martin Wild, Atsumu Ohmura, and Knut Makowski
    GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L04702, doi:10.1029/2006GL028031, 2007

    Incidentally, they include the reduction in diurnal temperature difference (or greater warming trend for night rather than day) in their analysis and provide the following explanation as to why it exists:

    Note that daytime temperatures are less sensitive to radiative changes than nighttime temperatures, since the radiative energy at the surface can be distributed more effectively by the turbulent fluxes of sensible and latent heat within the predominately convective daytime boundary layer, than during the predominantly stable nighttime conditions [Ohmura, 1984; Dai et al., 1999].

    (ibid.)

    Obviously the same sort of argument works for winter vs. summer trends in temperature. It is also worth noting that one of Ohmura’s current projects involves the measurement of increasing backradiation due to an enhanced greenhouse effect.

    *

    However, it is also worth pointing out that at this point we apparently do not have enough data to robustly conclude that solar brightening has occured.

    Please see:

    4. Conclusions

    [17] To summarize we show that there is a robust “global dimming” signal (by which we mean reduced globally averaged SWD) in climate models over the 20th Century. Overall, global mean model and satellite observational trends are smaller than previously reported for single sites or partial-global averages. This signal is attributable to the increased anthropogenic aerosol load rather than cloud feedbacks. However, over shorter decadal timescales, climate and SWD variability is dominated by cloud cover changes mainly associated with ENSO-related variability. Hence we conclude that recently reported evidence for “brightening” does not necessarily signify a general reversal of the 20th Century dimming trend due to reduced air pollution since the attribution of these changes in the presence of significant intrinsic variability is extremely difficult. Hatched regions denote at 95% confidence level.

    20th century changes in surface solar irradiance in simulations and
    observations
    A. Romanou, B. Liepert, G. A. Schmidt, W. B. Rossow, R. A. Ruedy, and Y. Zhang
    GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L05713, doi:10.1029/2006GL028356, 2007
    http://pubs.giss.nasa.gov/docs/2007/2007_Romanou_etal.pdf

    *

    In his point-for-point response, with respect to the cooling trend in the stratosphere, dean (#348) wrote:

    2. let me think about this one…

    *

    dean (#348) wrote:

    3. But what doesn’t match here is that the poles (plural) aren’t warming. Only the north pole is. And the fabled “northwest passage” has been open before only to close back. there is nothing new in what we’re seeing. It’s all happened before (in recent recorded history) and most likely will happen again. The north pole warming and the south pole not warming goes against the climatic models, doesn’t it?

    It would seem to me that there is plenty of warming — along the West Antarctic Peninsula. In fact it is experiencing the highest trend in temperature found anywhere in the world.

    Likewise, it would appear that the Antarctic troposphere is warming somewhat rapidly in the winter.

    Please see:

    Significant Warming of the Antarctic Winter Troposphere
    J. Turner, T. A. Lachlan-Cope, S. Colwell, G. J. Marshall, W. M. Connolley
    SCIENCE, 31 MARCH 2006, VOL 311, 1914-17

    … which is available at:

    Science – Significant Warming of the Antarctic Winter Troposphere
    Posted on: March 31, 2006 6:28 AM, by William M. Connolley
    http://scienceblogs.com/stoat/2006/03/science_significant_warming_of.php

    … and we know that Antarctica is experiencing mass balance loss — losing more ice over time than it gains, and that melting has occured recently within 310 miles of the south pole.

    Please see my earlier comment 106 to the post Climate Insensitivity. I include additional links to sources there.

    Likewise, I would suggest checking out my comment 135 in the same thread as it explains why some of Antarctica is cooling. But to put it briefly, in part it is largely isolated from the rest of the globe by the Antarctic circumpolar current, the stratosphere is lower and at times in contact with the surface, particularly given the transantarctic mountain range, and the temperature differential between the stratosphere and the troposphere due to increased cooling of the stratosphere as the result of ozone depletion results in stronger winds. However, I also point out that nearly all of the South Ocean is experiencing warming.

    *

    dean (#348) wrote:

    not only that, none of the models predicted the massive melt-off this year. So something other than what’s in the models caused it (or if it’s in the models, then it’s not accurately modeled).

    Gavin has dealt with that before. Actually the models do produce similar runs to what we are seeing in the Arctic Ocean. You just don’t see it when you average the runs. However, no one claims that the models are perfect. Still need to work on aerosols, clouds, the carbon cycle, etc.. But we are making progress in all of these areas.

    *

    dean (#348) wrote:

    4. But aren’t there questions as to the accuracy of that data? specifically, the weather station locations in urban areas (and don’t try to tell me that cities aren’t heat islands… ok, you can try, but i will not believe that because it just doesn’t make sense … I’ve leaned up against enough buildings after the sun’s set only to feel the bricks still radiating heat).

    With respect to the Urban Heat Island effect distorting surface temperature readings there is the little problem that satellite measurements of the lower troposphere show essentially the same trend.

    Please see:

    Satellite temperature measurements
    http://en.wikipedia.org/wiki/Satellite_temperature_measurements

    Apparently climatologists know how to correct for the biases due to the Urban Heat Island effect — beyond what is taken care of by a Cool Park Island effect.

    Please see:

    Abstract

    All analyses of the impact of urban heat islands (UHIs) on in situ temperature observations suffer from inhomogeneities or biases in the data. These inhomogeneities make urban heat island analyses difficult and can lead to erroneous conclusions. To remove the biases caused by differences in elevation, latitude, time of observation, instrumentation, and nonstandard siting, a variety of adjustments were applied to the data. The resultant data were the most thoroughly homogenized and the homogeneity adjustments were the most rigorously evaluated and thoroughly documented of any large-scale UHI analysis to date. Using satellite night-lights derived urban/ rural metadata, urban and rural temperatures from 289 stations in 40 clusters were compared using data from 1989 to 1991. Contrary to generally accepted wisdom, no statistically significant impact of urbanization could be found in annual temperatures. It is postulated that this is due to micro- and local-scale impacts dominating over the mesoscale urban heat island. Industrial sections of towns may well be significantly warmer than rural sites, but urban meteorological observations are more likely to be made within park cool islands than industrial regions.

    Assessment of Urban Versus Rural In Situ Surface Temperatures in the Contiguous United States: No Difference Found
    Thomas C. Peterson
    Journal of Climate, VOL. 16, NO. 18, 15 September 2003
    http://www.ncdc.noaa.gov/oa/wmo/ccl/rural-urban.pdf

    That paper is a modern classic.

    *

    Now before closing, I should focus for a moment on that point which I think is most important: we understand the physics behind the greenhouse effect. We aren’t simply going off of some funny correlation between the trend in temperature and carbon dioxide. Moreover, we can actually observe greenhouse gases emitting thermal radiation.

    But let’s make this fun. I won’t write about it. I will give you the images and motion videos. Here are a few links showing what we can get from spectral analysis of unwelling infrared radiation when you have satellites that can take readings on over two thousand different channels…

    Products – AIRS Carbon Dioxide
    NASA AIRS Mid-Tropospheric (8km) Carbon Dioxide
    http://www-airs.jpl.nasa.gov/Products/CarbonDioxide/

    Multimedia Animations
    http://airs.jpl.nasa.gov/Multimedia/Animations/

    Visualization of the global distribution of greenhouse gases using satellite measurements, by Michael Buchwitz. The Encyclopedia of Earth. Posted July 31, 2007
    http://www.eoearth.org/article/Visualization_of_the_global_distribution_of_greenhouse_gases_using_satellite_measurements

    For more links, check out comment 555 to the RealClimate » Part II: What Ångström didn’t know post.

    *

    Oh — I had also mentioned the fact that we have a database which includes over a million different spectral lines: the HiTran database (or “HIgh-resolution TRANsmission molecular absorption” database). The following interview with the gentleman in charge will tell you more about it…

    An interview with:
    Dr. Laurence Rothman
    http://cfa-www.harvard.edu/hitran/

    Enjoy.

  356. John Finn:

    Ok, sorry – it’s my fault. “Tongue-in-cheek” comments are clearly best delivered verbally rather than in type.

    Regarding Gavin’s response to my post (#340)

    No, Gavin, I wasn’t really suggesting that -129 deg C is the true effective temperature – neither do G&T. In your reply, you say

    That is a global mean calculation of course, but the difference using a realistic distribution of surface temperature is very similar (that is actually what GCMs calculate).

    This refers to the factor ‘4’ ratio calculation. But the G&T calculation is also a global mean calculation – of sorts. It just happens to be a calculation of a static (non-rotating) globe. The difference between the 2 calculations being the way in which solar energy is distributed – though the average is still the same. The G&T calculation is just an extreme example.

    The point is that the real (or any non-uniform) “non-greenhouse” global mean temperature will always be less than the radiation effective temperature of 255k. This, as the G&T paper states, is “a consequence of Holder’s inequality”.

    I know you know this since you claim that GCMs use a realistic distribution and get a “similar” result (to the 255K) . But how similar? And what is the real (greenhouse-included) mean temperature. You can’t get away from the fact that even if all major (known) climate factors remained constant (on average) – mean global temperatures could still vary.

    [Response: 255 K is the true effective emitting temperature, but in the real world there isn't one emitting layer and so calculating its average temperature doesn't make sense. You can only compare observables - the actual temperature distribution horizontally and vertically or the LW fluxes. G&T's calculations are just irrelevant. - gavin]

  357. John Finn:

    Hank

    Re: #345

    Yep. We know it happened, so, since the trees didn’t record it, that proves the tree rings are wrong.

    Actually there are very good reasons for thinking that tree rings do not capture climate fluctuations.As a thought experiment take a tree from the Malaysian rain forest (average annual temp ~26 deg C) and “replant” it in the western sahara (average annual temp also ~26 deg C). Does it grow the same in both locations. Tree rings, at best, simply capture temperature contribution to growth and even then only over a limited interval, e.g. it can get too warm for the tree to thrive.

    BPL Re:#342

    2. Increased sunlight would heat the stratosphere first. But we’re seeing stratospheric cooling. Partly this is due to ozone depletion, but the increase in greenhouse gases accounts for the rest of the effect

    How do we know the strat is cooling? It wouldn’t be from satellite data would it?

  358. Timothy Chase:

    John Finn (#356) wrote:

    Hank

    Re: #345

    Yep. We know it happened, so, since the trees didn’t record it, that proves the tree rings are wrong.

    Actually there are very good reasons for thinking that tree rings do not capture climate fluctuations. As a thought experiment take a tree from the Malaysian rain forest (average annual temp ~26 deg C) and “replant” it in the western sahara (average annual temp also ~26 deg C). Does it grow the same in both locations. Tree rings, at best, simply capture temperature contribution to growth and even then only over a limited interval, e.g. it can get too warm for the tree to thrive.

    You are right of course. Temperature by tree ring proxy is done by measuring the width of the rings. The wider the rings the higher the temperature. However, this assumes that you have sufficient moisture. If the years are drier in under higher temperature, the rings can’t grow as wide. So tree rings have limited use. At that point you have to rely upon other proxies.

    John Finn (#356) wrote:

    BPL Re:#342

    2. Increased sunlight would heat the stratosphere first. But we’re seeing stratospheric cooling. Partly this is due to ozone depletion, but the increase in greenhouse gases accounts for the rest of the effect

    How do we know the strat is cooling? It wouldn’t be from satellite data would it?

    Both by satellite measurements and by balloon. Balloon measurements are somewhat less reliable, but it helps to have both as a double-check. Over the United States we have roughly 70 radiosonde stations which send up balloons twice daily that reach 30 km, bursting at 10 mb. They take a variety of measurements along the way.

    Please see:

    RADIOSONDES — An Upper Air Probe
    http://www.aos.wisc.edu/~hopkins/wx-inst/wxi-raob.htm

  359. Jerry:

    To those people who seem to think that we KNOW what the solar flux was doing prior to careful satellite measurements, I would suggest that you take a look at Foukal, et al., 2004: A stellar view of solar variations and climate. Science, 306, 68-69. It is especially telling that the very folks who first came up with solar irradiance reconstructions now admit that previously calculated increases were too large by a factor of five.

  360. Larry:

    Paint the Earth White??

    If reflecting light is so important in the Artic, maybe try it else where along with reducing emissions?

    Dust farmland with some sort of white organic matter when not growing, make highways white, buildings reflective etc.?

  361. Jim Galasyn:

    Re Larry’s suggestion in 360, you might call this approach “albedo management,” and indeed there are places undertaking such projects. Switzerland, for example, has been placing large blankets of mylar over its glaciers to reduce the melt rate.

  362. Phil McCracken:

    I live just 20 miles from the ocean at an elevation of 200 feet. I estimate I have 40 years to live. Should I worry?

  363. David B. Benson:

    Phil McCracken (362) — Not due to sea stand rise. Other things to worry about tho’.

    Food and water supply, sufficient energy…

  364. Jim Eager:

    Re dean @ 348: “And the fabled “northwest passage” has been open before only to close back. there is nothing new in what we’re seeing.”

    Yes, the northwest passage certainly has been open before, many times in fact, but do you even have a clue where the northwest passage lies?
    See: http://www.marine.fm/en/nwpmapen.htm
    Note how it turns south at Resolute to head down Peel Sound and then hugs the coast all the way west.

    But we didn’t just see the northwest passage become ice free this summer.
    Have you bothered to look at the images and animations of this year’s melt to see the extent of the melt and where it lies in relation to the northwest passage?
    See: http://nsidc.org/news/press/2007_seaiceminimum/20070810_index.html

    Nothing new, indeed.

    Get a clue, dean. And while your at it, tell us how the Sun managed to do that while at solar cycle minima.

  365. Steve Bloom:

    Re #364: Jim, the map you linked shows the historical NWP that is known to open occasionally. It is not the one that’s discussed as a potential major shipping route, though. That one involves going straight through rather than taking the sharp left at Resolute, and opened this summer for the first time in the historical record. The northern route is preferred because it remains entirely within international waters, although it is within Canada’s economic zone. I suspect that because the southern route is so tight it may also be problematic for heavy ship traffic. Hopefully Wayne Davidson will read this and correct anything I didn’t get right.

  366. Hank Roberts:

    Dean, what are you relying on as a source for your information?
    Are you reading what you’re posting somewhere, that you consider a reliable source, and bringing them here and stating them as facts?
    I assume you are not doing all the work all by yourself in the library to get what you believe to be true. Who do you trust, whose work are you quoting from? Why do you consider your source to be reliable?

  367. Jim Eager:

    Re Steve Bloom @ 365: “Jim, the map you linked shows the historical NWP that is known to open occasionally. It is not the one that’s discussed as a potential major shipping route, though. That one involves going straight through rather than taking the sharp left at Resolute, and opened this summer for the first time in the historical record.”

    Indeed, Steve: http://nsidc.org/news/press/2007_seaiceminimum/images/20070920_extent.png

    But since, as you write, this is the first time in the historical record that the direct route through the McClure Straight has opened then it cannot be the one that dean referred to, since he states that it has been open before and that it being open is nothing new.

    As to the McClure route lying in international waters, that is something Canada strenuously disagrees with.

  368. Hank Roberts:

    Also useful found via NSIDC:

    “the Polar Science Center at the University of Washington’s Applied Physics Laboratory has created an animation of the 2007 sea ice thickness and extent (c) based on a combination of models and observed data. The animation shows the region of thick (greater than 3 meters [10 feet]) ice. In past decades, this thick ice spread across much of the central Arctic Basin. Recently, it has retreated to a narrow band along the northern Greenland and Canadian coasts …”

    http://psc.apl.washington.edu/zhang/IDAO/summer2007_arctic_seaice.gif

    This animation currently goes through October 31st, when sea ice began to recover. It’s quite stunning to see how _thin_ the ice is.

  369. David B. Benson:

    Here are some links which may prove useful regarding denialist arguments:

    http://en.wikipedia.org/wiki/Fallacy_of_many_questions
    http://en.wikipedia.org/wiki/Ignoratio_elenchi
    http://en.wikipedia.org/wiki/Argumentum_ad_baculum
    http://en.wikipedia.org/wiki/Fear%2C_uncertainty_and_doubt
    http://en.wikipedia.org/wiki/Logical_fallacy

  370. anonymous:

    global warming is a world wide issue and we all need to help out to keep our world from someday (maybe a hundred years, but SOMEday) falling apart.
    we need to take global warming seriously.
    and, David B. Benson, wikipedia is so not reliable. you could have changed it to your likes for all we know, whether you agree or disagree.

  371. Hank Roberts:

    Anonymous 3:56pm, “for all we know” isn’t correct; you can check.
    http://wikiscanner.virgil.gr/

  372. Steve Bloom:

    Re #367: You’re entirely correct as far as I know, Jim. Some of dean’s confusion may have been legitimate since a lot of the discussion in the media failed to distingush between the two, but if he had checked any of the original sources he could have avoided that. Hank’s continuing point about the advisability of checking sources before just saying stuff remains relevant. Dean should be advised that using denialist sites for sources (as I suspect he did in this instance) will lead quickly to this sort of confusion.

  373. Ray Ladbury:

    Anonymous, #370. Actually, I have found Wikipedia quite good wrt scientific subjects. This is also the conclusion of a study last year that found Wikipedia as accurate as Brittanica on matters of science. Do you have data suggesting otherwise?

  374. David B. Benson:

    Ray Ladbury (373) — Yes, Wikipedia can be a good place to start, but it is often the case that other sources should also be checked. (Same applies to any first source.)

    In any case, the links are to forms of incorrect ‘reasoning’ or argumentation, not science. Look good enough for me, not being rhetorician.

  375. larry W:

    Reply to some comments on my posting #308: Comments with the reference to follow- Glaciers have been shortening at nearly a constant rate for the last 180 years. ( Oerlemanns, J. (2005) Science 308,675-677. Sea level has been increasing at about 7 inches per century for the last 150 years with intermediate trends of 9,0,12,0,and 12 inches per century, respectively. (et al.(2006) J.Geophysical Res. 111. & (2004) Marine Geodesy 27, No. 1-2,79-94.
    Global Mean Temperature from 1910 to 1945 shows nearly the same slope as the last 25 years. The period 1940 to 1980 covers the war period and the periods of fossil fuel use with high sulfur content. (Frequently Asked Questions for IPCC Summary) FAQ 3.1 Figure 1.
    Contribution of sulfur removal to earth warming: According to model calculations by Brasseur and Roeckner (205) complete improvement in air quality could lead to a decadal global average surface temperature increase by 0.8 K on most continents and 4 K in the Artic. Further studies by Andreae et al. (2005) and Stainforth et al. (2005) indicate that gobal average climate warming may even surpass the hightest values in the projected IPCC global warming range of 1.4-5.8 degree C (Cubasch et al., 2001)
    Summary: Both glacier melting and sea level rise history both point to heating before significant carbon emissions. Recent rises in temperature are most likely due to both carbon dioxide increases and sulfur removal with the latter having better life experience support. Finally, the Hadley Centre Global Mean Surface temperature has been flat for the last five years. For the reasons above and many others, like a poor closing to the carbon balance and the under water volcanic activity, I am still in the camp that things are much more complex than just calling carbon dioxide a pollutant and going for its throat.

  376. Ray Ladbury:

    Re 375. So, Larry, where’s all the energy coming from that is raising temperatures so much and melting all this ice? It is not greater solar irradiance. And increased solar irradiation would not explain why nightime lows are increasing faster than daytime highs. Do you have a model, or do you just wave your hands a lot and hope nobody notices that you are creating energy out of nothing?

  377. Hank Roberts:

    > things are much more complex than just calling carbon dioxide

    See Gavin’s inline response to Nick, re this same strawman setup:
    http://www.realclimate.org/index.php/archives/2007/11/a-phenomenological-sequel/langswitch_lang/in#comment-71395

    Nobody thinks it’s simple.

  378. larry W:

    Re #376 I guess I can turn the question around and ask where did the heat come from for the period 1910 to 1945 when it had nearly the same slope as the last 25 years? The glacier receeding rate and ocean level rise data I assume is correct. The period 1945 to 1980 is relatively flat and marks the period of the war and the burning of fossil fuels without much sulfur removal. David I. Stern studied global sulfur emissions from 1850 to 2000 with a peaking between 1975 and 1990 and then a sharp drop. Sulfur is not the only component to cooling but it is probably the greatest.
    When looking at the Radiative forcing of climate for the period 1750 and 2005 shown in FAQ 2.1, Figure 2 I see a lot of uncertainty in the total aerosol component. The cloud albedo effect has a maximum negative of -1.8 which is about the same as the CO2 maximum. I have a gut feeling the removal of sulfur is causing a lot of the rise of temperature blamed on CO2. Sulfur clears has a more data to back up its cooling effect. Yes CO2 is contributing but not as much as the public thinks.
    I still feel a warmer earth with enhanced growth rates of plants with higher CO2 is not a bad thing. I just returned from South Africa where they have miles and miles of pine forest that once was grass land. Pine trees have a very positive growth rate response to increased CO2 (40%).Driving up energy cost for the poor is worse and can have an adverse effect on our country’s economic health. Based on the Nanotechnology publications I get we should have competitive solar power within 20 years. Chinese companies are jumping into the solar power game and will probably beat us to the punch. Couple that with the big push for nuclear power in China and we will have our hands tied trying to be competitive.
    Where is the heat coming from? Not sure but the ocean is a large body of water surrounded by and covering volcanoes still to be discovered. Have you seen the picture of a saiboat plowing through volcanic ash floating on the surface? Very scary as he had thought he had run aground with nothing on the charts. The earth molten center is very active and is due for a magnetic field switch and this movement can be shifing the heat loss distribution around the globe. Very complex.

  379. Barton Paul Levenson:

    larry W writes:

    [[The earth molten center is very active and is due for a magnetic field switch and this movement can be shifing the heat loss distribution around the globe.]]

    The average geothermal flux at Earth’s surface is about 0.087 watts per square meter. By way of contrast, the flux absorbed from the sun by the Earth system is 237 watts per square meter. Divide A by B to get the ratio of importance as far as Earth’s climate goes.

  380. Ray Ladbury:

    Larry W, your post is an excellent example of why scientists shouldn’t listen to laymen when it comes to scientific matter. It is a mish-mash of technological optimism, obfuscation and trial balloons with no consideration as to their relative magnitudes. First, whether it is solar power or nuclear power, it will take decades before either can supply even a significant fraction of global energy needs. And solar still has to resolve the energy storage/backup issue before it is viable. It never ceases to amaze me how people can assume that technology will save us even as they cut back on basic research on which that technology would have to be based.
    So it’s the oceans, huh? Well, then why are the oceans getting warmer, too? This one doesn’t fly. Most of the Ocean is actually quite cold.
    And your idea about the energy coming from Earth’s core is laughable. First, we’d be able to measure such a large increase. Second, the magnitudes are not even close.

    More generally, you seem to want to explain the unknown in terms of the unknown. That’s not science, but rather rationalization for complacency.

  381. Mary C:

    Re 378. Can somebody please clarify for the layman the difference in reliability between a “gut feeling” and the gazillions of measurements, reams of research, and scientific theories used by climate scientists? This seems to be part of the problem for the general public. As far as I can tell, a lot of people seem to think that denialists’ “gut feelings” are in opposition to the climate scientists’ “gut feelings”. Obviously, the latter have forgotten all about other warming possibilities than CO2 such as solar irradiance, cosmic rays, and heat from within the earth, so let’s go with the more understandable–and more comfortable–set of “gut feelings”. Quite seriously, I think that many people, including sometimes scientists from other disciplines, have absolutely no idea what the conclusions of the climatologists are based upon, hence, their difficulty in accepting the case for AGW and the ease with which they can be swayed by denialist arguments. Not sure how the scientific community can get around this problem since reeling off numbers and explaining theories will most likely only cause many people’s eyes to glaze over while the denialist explanations frequently seem like, well, common sense.

  382. Ray Ladbury:

    Mary C. When in doubt, I try to go back to basics–start with conservation of energy. It takes energy to increase the temperature of a body as big as Earth. It takes energy to melt all that ice. Where is that energy coming from? Well, if you’re a scientist, you start looking at the sources of energy that go into the climate. Very quickly, you see that it cannot be the Sun, since total solar irradiance has been flat or decreasing when we’ve had the most warming recently. The next most important contributor of energy to the climate is the greenhouse effect. Water vapor has such a short residence time in the atmosphere and fluctuates so much that it’s not a good candidate to explain a long-term, steady rise in temperature. However, the 2nd most important ghg is CO2–and that’s a very good candidate. It is also a candidate where we understand the physics very well. You can continue thus and find that CO2 really is the key, and that the other mechanisms really don’t come close.
    The bottom line, though, is the energy has to come from somewhere. Even if you say “it’s all natural”, you have to have an energy source, or you don’t have a scientific theory. Right now, there’s only one theory–anthropogenic CO2.

  383. larry W:

    Thanks guys but you still did not answer the most important question I posed and that is what caused the increase in the temperature for the period 1910 to 1945 that has very close to the increase rate as the last 25 years. Also, no one wants to answer the sulfur removal effect. I agree CO2 is a green house gas and has an influence, but something else is at work and we should not stop looking. Clearly global mean air temperature has been flat for four years and global sea temperatures may be dropping slightly. I want real data and not model predictions. Thanks

  384. Ray Ladbury:

    Larry W,
    No one answered them because they are not directly relevant. We did not have a globe bristling with instrumentation in 1910 as we do now, so we do not know all the contributors. Increased solar activity played a role–and CO2 was increasing rapidly then as well (remember the contribution is logarithmic in CO2 content). As to sulfur, whatever the source, it stays in the atmosphere for a few months to a few years. CO2 stays for hundreds of years. Oh, and the models are based on real data. Learn something about them.

  385. Barton Paul Levenson:

    larry w writes:

    [[Thanks guys but you still did not answer the most important question I posed and that is what caused the increase in the temperature for the period 1910 to 1945 that has very close to the increase rate as the last 25 years.]]

    The most likely primary cause for the early 20th century warming is the increase in solar luminosity which took place at that time.

    [[ Also, no one wants to answer the sulfur removal effect. I agree CO2 is a green house gas and has an influence, but something else is at work and we should not stop looking. Clearly global mean air temperature has been flat for four years]]

    You don’t determine a trend from four points. Not when you have over 120 available.

    [[ and global sea temperatures may be dropping slightly.]]

    Says who? What’s your source for this statement?

    [[ I want real data and not model predictions. Thanks]]

    Then go to the NOAA and NASA GISS sites and download the data files.

  386. SecularAnimist:

    larry W wrote: “Based on the Nanotechnology publications I get we should have competitive solar power within 20 years. Chinese companies are jumping into the solar power game and will probably beat us to the punch.”

    That much of what Larry W wrote is true.

    According to WorldWatch Institute, global production of photovoltaic cells “has risen sixfold since 2000 and grew 41 percent in 2006 alone” and “grid-connected solar capacity … increased nearly 50 percent in 2006.” WorldWatch notes that in 2006, “China passed the United States … to become the world’s third largest producer of the cells — trailing only Germany and Japan … China’s leading PV manufacturer, Suntech Power, climbed from the world’s eighth largest producer in 2005 to fourth in 2006 … China, with its growing need for energy, large work force, and strong industrial base, could drive dramatic reductions in PV prices in the next few years, helping to make solar competitive with conventional power even without subsidies.”

    Regarding new PV technologies, WorldWatch notes that “supply shortages have led manufacturers to find ways to use polysilicon more efficiently, and have accelerated the introduction of new technologies that do not rely on purified silicon and are inherently less expensive to manufacture. So-called thin film cells can be made from amorphous silicon and other low-cost materials, and companies developing these technologies have recently become the darlings of Silicon Valley venture capitalists. Although in the past, thin film cells have not been efficient enough to compete with conventional cells, today over a dozen companies — including Miasole, Nanosolar, and Ovonics — are competing to scale up production of low-cost solar modules that can be churned out like rolls of plastic.”

    With regard to wind power, WorldWatch Institute reports that “global wind power capacity increased almost 26 percent in 2006″ and that “the 15,200 megawatts of new wind turbines installed worldwide last year will generate enough clean electricity annually to offset the carbon dioxide emissions of 23 average-sized U.S. coal-fired power plants”.

    The rapid and accelerating worldwide growth of solar and wind generated electricity is definitely one bright spot in the overall CO2 emissions picture. The imminent availability of mass-produced ultra-cheap thin-film photovoltaics has the potential to further accelerate the growth of solar electricity and indeed to revolutionize the production, distribution and use of electricity, much as the personal computer revolutionized “data processing” and the cell phone revolutionized telecommunications.

    In the industrialized world, demand-side changes — elimination of waste, energy conservation and improvements in efficiency — are still the best, fastest and cheapest ways to reduce energy-related carbon emissions. In the developing world, the best, fastest and cheapest way to provide low-carbon electricity to meet growing demand is a rapid expansion of solar and wind generating capacity.

  387. larry W:

    Thank you #386. You did a fantastic job demonstrating my point that solar power is here and growing very rapidly, expecially in China. With regard to the comment on storage of electricity batteries are getting better as are inverters to convert to AC. Most systems now connect to the grid with flow in both directions.

    Response to #384. You are correct that if we wanted to remove all CO2 added by man it might take 100 years, but the time to reduce 50% is much shorter. Again a log function. So now past temperature data is not directly revelant, but should we not have to put some faith in data that has many corrections applied. So I can assume that solar activity is the major influence in the temperature change and CO2 had an influence that greatly decreaed after 1945.

    Response to #385: The global temperature came from Hadley Centre and I used just the last 4 years but it has in fact been only lightly up since 1997.
    The sea temperature data can from NASA/NOAA website 09.21.06 Titled: Short-term Ocean Cooling Suggests Global Warming ‘Speed Bump’ They did a very comprehensive massing of all avialble data from 1993 to 2005. Over 1993 to 2003 the temperature increase 0.016 F/yr yet from 2003 to 2005 it dropped 0.027 F/yr. An e-mail to Swally for an update came back with the comment that they found some data collection error and the trend from 2003 is now flat to slightly down with the corrections waiting for publication.

    I still need answers to the glacier references and sea level rise rates I quoted.

  388. Ray Ladbury:

    Uh, Larry, do you have even the foggiest notion what you are talking about? The half life of CO2 in the environment is closer to 800 years if I recall correctly. And it decays exponentially, so it takes a long time to return back to its previous value.

    And no I didn’t say past climate is irrelevant, just that there are more uncertainties to energetics than we have now. You can assume whatever you want since you aren’t a scientist and so not bound to follow evidence. Feel free to be wrong.

  389. Barton Paul Levenson:

    larry w continues on the same path as before:

    [[The sea temperature data can from NASA/NOAA website 09.21.06 Titled: Short-term Ocean Cooling Suggests Global Warming ‘Speed Bump’ They did a very comprehensive massing of all avialble data from 1993 to 2005. Over 1993 to 2003 the temperature increase 0.016 F/yr yet from 2003 to 2005 it dropped 0.027 F/yr. ]]

    Larry, we have direct temperature data going back to 1850. You can’t tell the overall trend from three-four years, ten years, or eleven years. It is IRRELEVANT that temperature declined from 2003 to 2005. That is simply not a large enough sample size.

    You have to use all the data. Not just a bit of it that seems to support your idea.

  390. larry W:

    Response to # 388. Your are right I am not a scientist just an engineer. I read an article that said if we stopped all input by man today it would take 100 years to remove 99% but a lot fewer years to remove 50%. This sounded reasonable if we include only the interaction between plant life and the ocean surface. If you include the total ocean volume and subsurface land CO2 it is much more complex. The earthobservatory.nasa.gov/Library/Carboncycle/printall.php gives an estimated carbon balance with fuel and land use inputing 7.1GT per year. They estimate 3.2 GT goes to CO2 build up and 2.0 GT to the ocean. They state that the scientist do not know what heppens to the leftover 1.9GT. However, the comment was made that several scenarios could cause the land to uptake more carbon dioxide than is released each year. In a subsequent publication on the BOREAS project,they now believe that a lot of the missing carbon is being taken up by areas above 40 degrees N latitude which cuts the middle of the US. The BOREAS project saw the average uptake of 30 grams/sq meter but also some Aspen going over 200 grams. What is your 800 year calculation based on and where do you get your data on the carbon balance?

    [Response: 800 years is more like the right number, and even then, there's about 20% of the anthropogenic CO2 still stuck in the atmosphere (and the ocean, of course is acidified). Take a look at some of the articles by Dave Archer on RealClimate, on the subject of CO2 lifetime. Then read some of his scientific papers. That will get you a start. He also has an accessible book on this subject for the lay reader coming out from Princeton U. Press. --raypierre]

  391. veritas36:

    Gavin,

    Can you resolve for me this discrepancy?
    Singer has listed himself as ’1962-1964, (First) Director, National Weather Satellite Center’ http://www.sepp.org
    But this NOAA web page refers to David Simonds Johnson as “the founding director of the National Weather Satellite Center”
    http://preserveamerica.noaa.gov/week06/johnson_pioneer.html
    ??

  392. CobblyWorlds:

    #390 Larry,

    Just browsing, if I have the wrong end of the stick ignore me.

    a) On the CO2 levels and Gavin’s comment.

    As a start I’d recommend Archers’ “Fate of fossil fuel CO2 in geologic time”
    http://geosci.uchicago.edu/~archer/reprints/archer.2005.fate_co2.pdf
    e.g.
    “A mean atmospheric lifetime of order 10^4 years is in
    start contrast with the “popular” perception of several
    hundred year lifetime for atmospheric CO2. In fairness, if
    the fate of anthropogenic carbon must be boiled down into a
    single number for popular discussion, then 300 years is a
    sensible number to choose, because it captures the behavior
    of the majority of the carbon. A single exponential decay of
    300 years is arguably a better approximation than a single
    exponential decay of 30,000 years, if one is forced to
    choose. However, the 300 year simplification misses the
    immense longevity of the tail on the CO2 lifetime, and
    hence its interaction with major ice sheets, ocean methane
    clathrate deposits, and future glacial/interglacial cycles.”

    Then after that try reading “Long term fate of anthropogenic carbon” Montenegro et al, also from Archer’s publications page.
    http://geosci.uchicago.edu/~archer/reprints/montenegro.2007.fate_CO2.pdf
    e.g.
    “The average
    perturbation lifetime of 1800 years is much longer than the
    300–450 years proposed by some other studies [Archer et
    al., 1997; Archer, 2005]. Given the large differences in
    model type and experiment set up between the present and
    previous experiments, these comparisons should be made
    with care. While there still is a great deal of uncertainty at
    these longer timescales, our results indicate that the long
    term consequences of anthropogenic climate change may be
    much greater than previously thought.”

    The details are unclear (as so often), but the broad message remains: In terms of the timescales of human history our “Terraforming” experiment is very likely irreversible.
    Welcome to the Anthropocene. ;)

    b) On the recent abatement of the warming, this might help:
    http://www.sciencemag.org/cgi/content/abstract/317/5839/796 Hadley Centre DePreSys study: “Our system predicts that internal variability will partially offset the anthropogenic global warming signal for the next few years.”
    And from a photocopy of a summary of the paper:
    “In the DePreSys forecast, internal variability offsets the effects of anthropogenic forcing in the first few years, leading to no net warming before 2008 (Fig. 4). In contrast, the NoAssim forecast warms during this period. Regional assessment to February 2007 (fig. S8) indicates that this initial cooling in DePreSys relative to NoAssim results from the development of cooler anomalies in the tropical Pacific and the persistence of neutral conditions in the Southern Ocean. In both cases, the DePreSys forecast is closer to the verifying changes observed since the forecast start date. Both NoAssim and DePreSys, however, predict further warming during the coming decade, with the year 2014 predicted to be 0.30° ± 0.21°C [5 to 95% confidence interval (CI)] warmer than the observed value for 2004. Furthermore, at least half of the years after 2009 are predicted to be warmer than 1998, the warmest year currently on record.”
    i.e. “natural” factors in the Pacific and Southern Ocean are indicated as being responsible for the abatement.
    Reference to the HADCRU Global Near Surface dataset seems to support this. http://www.metoffice.gov.uk/research/hadleycentre/CR_data/Monthly/HadCRUGNS_3plots.gif
    Notice the reduced Southern Hemisphere trend, whilst the Northern Hemisphere shows nothing unusual.

  393. David B. Benson:

    CobblyWorlds (392) — Likely enough irreversile, unless we figure out a way to convince people to put the fossil carbon back in the ground. The technical means are available. So far, the will to do so on a massive scale is not. :-(

  394. Mark:

    Re: Ike [If CO2 has always risen after temperature has, why should it be different now, no matter how much more CO2 is in the atmosphere?]

    Well, take a measurement. Do the measurements in the past show temperature rises before or after CO2 rises IN THIS CASE?

    Before.

    In this case.

    It doesn’t matter if three thousand years ago, CO2 rose after temperatures did because, basically, it is no longer three thousand years ago. So now that we know (by measurement, not model) that CO2 is preceeding temperature change (where’s the 800 year old rise in CO2 otherwise?) what has changed. Well, dino’s didn’t have oil wells, cars, refrigeration etc, so maybe that is the reason. Why would it have an effect? Because those processes require burning fossil fuels which release CO2.

    The odd thing about that sceptic argument is that it is taking what they complain about AGW scientists are doing: assuming that because this model is right in the past, it must be right in the future and not waiting to see if measurements agree. However, for the sceptics, it’s that in the past CO2 lagged behind temperature and so this is what must be happening now, without having a butchers at the measurements. Worse is that the sceptics could go back and see the measurement record rather than having to wait to see them, since they argue the CO2 increase was in the past and the temperature increase is in the present, whereas AGW is saying CO2 is now (measured) and temperature increase is in the future (cannot measure it now).

    Daft, innit.

  395. Mark:

    Re: Ralph 305: How about asking “what will happen if we reduce CO2 by 100ppm” and then try to get there. If AGW is true, then this stops us getting to a bad situation (unless we’ve passed a tipping point, which is what the models are trying to find out). If AGW is incorrect then we’ve got a cleaner planet.

    Industry believes that this is bad and the sceptics think this means we are all being asked to live in caves. However, I don’t see any models from them about how changes in industry that would lead on from increasing/reducing CO2 production will affect industry, just assertions that it WILL be bad. The Stern report got closest but that wasn’t Industry. Now if they were to make such a model, will the sceptics disbelieve them when it comes up with “living in huts” or will they only disbelieve it when it comes up with “meh, fewer iPods sold”?

    The answer to that question will show you what the sceptics motivations are.

    Pity industry won’t do it, though.

  396. Mark:

    Re: John Finn (357). How many people in the middle ages in europe transplanted trees from malasia into england? And if they did, how come the only tree ring we could find was this malasian transplant?

    Or were you being funny?

  397. Mark:

    Dang it. Sorry. Where is the 800 year old temperature rise that’s causing the CO2 to jump up.

    Cart Horse.