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Unsettled Science

Filed under: — gavin @ 3 December 2009

Unusually, I’m in complete agreement with a recent headline on the Wall Street Journal op-ed page:

“The Climate Science Isn’t Settled”

The article below is the same mix of innuendo and misrepresentation that its author normally writes, but the headline is correct. The WSJ seems to think that the headline is some terribly important pronouncement that in some way undercuts the scientific consensus on climate change but they are simply using an old rhetorical ‘trick’.

The phrase “the science is settled” is associated almost 100% with contrarian comments on climate and is usually a paraphrase of what ‘some scientists’ are supposed to have said. The reality is that it depends very much on what you are talking about and I have never heard any scientist say this in any general context – at a recent meeting I was at, someone claimed that this had been said by the participants and he was roundly shouted down by the assembled experts.

The reason why no scientist has said this is because they know full well that knowledge about science is not binary – science isn’t either settled or not settled. This is a false and misleading dichotomy. Instead, we know things with varying degrees of confidence – for instance, conservation of energy is pretty well accepted, as is the theory of gravity (despite continuing interest in what happens at very small scales or very high energies) , while the exact nature of dark matter is still unclear. The forced binary distinction implicit in the phrase is designed to misleadingly relegate anything about which there is still uncertainty to the category of completely unknown. i.e. that since we don’t know everything, we know nothing.

In the climate field, there are a number of issues which are no longer subject to fundamental debate in the community. The existence of the greenhouse effect, the increase in CO2 (and other GHGs) over the last hundred years and its human cause, and the fact the planet warmed significantly over the 20th Century are not much in doubt. IPCC described these factors as ‘virtually certain’ or ‘unequivocal’. The attribution of the warming over the last 50 years to human activity is also pretty well established – that is ‘highly likely’ and the anticipation that further warming will continue as CO2 levels continue to rise is a well supported conclusion. To the extent that anyone has said that the scientific debate is over, this is what they are referring to. In answer to colloquial questions like “Is anthropogenic warming real?”, the answer is yes with high confidence.

But no scientists would be scientists if they thought there was nothing left to find out. Think of the science as a large building, with foundations reaching back to the 19th Century and a whole edifice of knowledge built upon them. The community spends most of its time trying to add a brick here or a brick there and slowly adding to the construction. The idea that the ‘science is settled’ is equivalent to stating that the building is complete and that nothing further can be added. Obviously that is false – new bricks (and windows and decoration and interior designs) are being added and argued about all the time. However, while the science may not be settled, we can still tell what kind of building we have and what the overall picture looks like. Arguments over whether a single brick should be blue or yellow don’t change the building from a skyscraper to a mud hut.

The IPCC reports should be required reading for anyone who thinks that scientists think that the ‘science is settled’ – the vast array of uncertainties that are discussed and dissected puts that notion to bed immediately. But what we do have are reasons for concern. As Mike Hulme recently wrote:

[S]cience has clearly revealed that humans are influencing global climate and will continue to do so, but we don’t know the full scale of the risks involved, nor how rapidly they will evolve, nor indeed—with clear insight—the relative roles of all the forcing agents involved at different scales.

The central battlegrounds on which we need to fight out the policy implications of climate change concern matters of risk management, of valuation, and political ideology. We must move the locus of public argumentation here not because the science has somehow been “done” or “is settled”; science will never be either of these things, although it can offer powerful forms of knowledge not available in other ways. It is a false hope to expect science to dispel the fog of uncertainty so that it finally becomes clear exactly what the future holds and what role humans have in causing it.

Dealing with the future always involves dealing with uncertainty – and this is as true with climate as it is with the economy. Science has led to a great deal of well-supported concern that increasing emissions of CO2 (in particular) are posing a substantial risk to human society. Playing rhetorical games in the face of this, while momentarily satisfying for blog commenters, is no answer at all to the real issues we face.

567 Responses to “Unsettled Science”

  1. 251
    Anand Rajan KD says:

    BPL: Your argument therefore is that AGW proponents are justified in using the term ‘denialists’. Everyone uses abusive terms – your choice is the word ‘denialist’. Why this word? I believe that was the question.

    Why talk about balance? Posts here get deleted, moulded. The emails say that a close watch will be kept on the posts.

    Do you know how a deleted post can read? I reads the exact opposite way it was meant to be read.

    If you guys will go to such lengths as to keep track of individual posts, imagine what you would do with papers.

    Those who are confident of their own science wouldn’t bother so much about prevailing counterpoints and their ‘public impact’ Bothering too much about public impact is not a scientist’s job. Like I’ve said before, keep your nose down.

    The minute you guys publish your papers, you want to wave photocopies of your papers in front of government officials and polar bears. And then pretend to be shocked that people have different opinions. Or do not share the same intensity of belief that you do. Grow up.

    The opposite viewpoint is shocking only to a fundamentalist. There are all kinds of idiots and geniuses in this world. Nothing prevents them from using their brains and speaking out their thoughts. If I were a AGW denier, RealClimate comments would look horrid to me too.

  2. 252
    Anand Rajan KD says:

    oops wrong thread (re: previous comment)

  3. 253
    Krog says:

    I don’t understand your response to my question.

  4. 254
    Tom Street says:

    The science will never be persuasive for those whose interests conflict with the actions necessary to act upon its conclusions. Even if scientists were 99.9% sure that our current path will lead us to extinction, this will not be worth the risk, for some, of having any short term impact on their bottom line. Unfortunately, those who argue we should do nothing will be long since gone when our descendents have to pay the piper. Life may go on, but it will be nasty, brutish, and short, just like the old days.

    While good scientists are very careful in conducting their science, they need to learn to be more careful in expressing themselves and speak as if they have just been read the Miranda notice. Anything you say can and will be used against you.

    We have all had our emails misunderstood, even by those not out to get us. It is no surprise that release of thousands of emails would result in some that seem to cast a bad light on the climate scientists who wrote them.

  5. 255
    Brian Dodge says:

    “Below are various papers I have found falsifying the credibility of climate predictions (at least those based on these climate models).”
    Mike M — 5 December 2009 @ 9:02 AM

    If you think this paper is “falsifying the credibility” you either haven’t actually read it, or don’t understand the math.
    “Moreover, the data that we have on extreme climates [for example, the Eocene warmth and Proterozoic “snowball Earth” (20, 21)] suggest that the climate system may have been acutely sensitive to radiative forcing during some intervals of Earth’s history. Our results imply that dramatic changes in physical processes are not necessary for dramatic changes in climate sensitivity, provided that those changes in processes can all align in the same direction toward increased sensitivity. These are events of low but not zero probability.”
    “However, the probability that {Delta}T lies in the interval immediately outside the range of the Intergovernmental Panel on Climate Change (IPCC) (say, 4.5°C ≤ {Delta}T ≤ 8°C) is very insensitive to {sigma}f and f and changes little with {Delta}Tc. ”
    According to their Figure 3, there is ZERO probability that the sensitivity is less than 1.5 deg C, maximum probability that the sensitivity is 2.5-3 deg C and a greater than 10% probability that the sensitivity is 5 deg C for doubling CO2.
    “We have shown that the uncertainty in the climate sensitivity in 2 x CO2 studies is a direct and general result of the fact that the sum of the underlying climate feedbacks is substantially positive. Our derivation of hT ({Delta}T) did not depend on nonlinear, chaotic behavior of the climate system and was independent of details in cloud and other feedbacks.” What might change the probability? Positive feedbacks – yep; makes things worse. Chaotic behavior – nope. Clouds – nope.

  6. 256
    Dick Veldkamp says:

    Sorry to bug you Gavin, but could you write a line or two in response to my #199 ? I could use the info to debunk the notion of ‘cooling since 1998’ in some other web discussions. Thanks.

  7. 257
    Brian says:

    #202: Good point.
    #213:”How would you know? Do you know enough climatology to intelligently critique what they’re saying? Or are you just going by your political ideology?”:

    Why don’t I believe the proof of global warming? One reason is the data that exists to create the models. If there existed data going back a million years, made with tons of accurate thermometers placed all over the world–in the oceans and in the air, then I’m inclined to believe it is possible to model the future of the world’s weather accurately, given that we also understand what caused temperature fluctuations during those past years. But, my understanding is that we don’t have that data.

    I don’t believe that it is my political ideology that affects my opinion on global warming. As I said, I believe in reducing our impact on the earth, and I appreciate that global warming has increased awareness on the impact we have.

  8. 258
    David B. Benson says:

    Dick Veldkamp (256) — BPL has done a good job of that on another thread recently.

    Brian (257) — Data is not used to “create” the models; physics is:

    We also have hundreds of thousands of years worth of proxy data from Antarctic ice cores and many millions of years from benthic cores, compiled into the LR04 benthic stack. So it appears you need to read some more about reality. I suggest starting with “The Discovery of Global Warming” by Spencer Weart:
    after reading Andy Revkin’s review:

  9. 259
    dhogaza says:

    One reason is the data that exists to create the models. If there existed data going back a million years, made with tons of accurate thermometers placed all over the world–in the oceans and in the air, then I’m inclined to believe it is possible to model the future of the world’s weather accurately, given that we also understand what caused temperature fluctuations during those past years. But, my understanding is that we don’t have that data.

    What you *really* don’t understand is how the models are constructed, and how they work, which unfortunately makes your statement nonsensical.

    Climate science seems to be one area where people feel that they’re qualified to judge without putting in the effort to learn the first thing about whatever it is they’re pontificating about.

  10. 260
    Krumhorn says:

    Great! So Gerlich and Tscheuschner are “cranks”. Isn’t that precisely the attitude revealed in the climategate emails that has turned so many heads to look crab-eyed at ‘climate scientists’?

    Terms like ‘deniers’ and ‘cranks’ aren’t winning you any friends, and it’s precisely that kind of snotty arrogance that has brought you to this sad place. When the Jon Stewarts of the world mock that sort of thing, you know you are on the down slope of your influence.

    [Response: I’m sorry if it bothers you that science is not a democracy. But cranks exist in all fields (medicine, physics, climate etc.) and if you think they should be treated as scientific equals might I suggest a leach treatment the next time you have a cold? This is not ‘arrogance’, this is science. – gavin]

  11. 261
    Jim Ogden says:

    re: 234
    Gavin, your response of “Try reading our archives” is rather flippant. What you don’t seem to understand is that the public has lost trust in climate scientists. Perhaps you have been occasionally critical of Al Gore on this obscure website. Maybe you’ve even been critical of climate models, but that won’t cut it at this point. Rasmussen says “Fifty-nine percent (59%) of Americans say it’s at least somewhat likely that some scientists have falsified research data to support their own theories and beliefs about global warming.” You need need to be contrite, not flippant. You need to get out in front of this publicly. The public doesn’t read this website. Your profession is under siege. You are probably a fine, honest scientist.
    The time has come for you and others to speak out and clean up climatology. It’s not good enough to let politicians deceive while you quietly snicker amongst yourselves.

  12. 262
    Matthew says:

    What do you think are the most unsettled issues and how do they affect our plans and actions for the future?

    A Partial list:

    1. The models are unsettled. There isn’t an AGW model that correctly predicted the lack of warming after 1998, and none of the GCM models even predict the recent past from earlier years. Some relatively simple statistical extrapolations of the past trends (with periodic terms to represent the apparent cycles of warming and non-warming) predicted a reduction in warming after 2000, but these are not widely respected among the climate science community. Shouldn’t they gain some credibility from their evidently correct prediction?

    [Response: Not true in any respect. But I’ll put up a post on this soon. – gavin]

    2. How big is solar forcing really? The energy change is small, but the effect of the solar wind on cosmic rays is greater. If it is big enough, which is not known, then we are in for some decades of cooling, or at least non-warming.

    [Response: Very unlikely for all the reasons discussed in solar-related posts in the archive. – gavin]

    3. What is the residence time of anthropogenic CO2 (and others)? IPCC assumed a residence time much in excess of published measured residence times. How much does this affect predictions?

    [Response: Not true either. Residence time for a single molecule in the atmosphere (~5years) is not the same as perturbation time of atmospheric CO2 because of the rapid equlibration with the small terrestrial and upper ocean reservoirs. Those processes lead to very much longer timescales, with uptake regulated by the transport into the deep ocean which is much slower. – gavin]

    4. What is the effect of increasing H2O? Estimates are all over the place. IPCC assumed that the H2O effect was a positive feedback, but the feedback could be negative.

    [Response: A positive water vapour feedback is an observed fact (ENSO, volcanoes, long term trend), not an assumption. – gavin]

    5. What is the effect of increased growth rates and drought resistance that higher CO2 concentrations have on plants? Do higher CO2 concentrations in seas and lakes increase the plant growth rates?

    [Response: This is more interesting – but it is isn’t any reason to discount any other problem with increasing CO2 (or other GHGs) – including issues associated with increasing acidification in the oceans. – gavin]

    6. Last, for now, If you propose to spend $2Trillion in 10 years, what ways of spending it would really be of most benefit to the Earth’s poor people? Rapidly rebuilding the energy infrastructure of the rich nations does not seem to be the best way to spend the money.

    [Response: Spending money on the developing world to provide clean drinking water to everyone would cost $50bn and would be a great thing to spend money on. Given that the Iraq war cost $1Tr, it isn’t climate policy that is holding this spending back. – gavin]

    Those are just a few.

    “The science is settled” has come mostly from Al Gore and like-minded individuals. Scientists have drawn attention to areas needing research, and the global warming skeptics have drawn attention to the ways in which “The science is settled” isn’t a true statement.

  13. 263
    ccpo says:

    As a previously uninterested simple tax payer my first question is where are the long term analysis for temp & co2? There seems to be much sparing and talk about short term changes.

    The series of charts I came across for the past 400,000 years show cyclical changes:
    1/ both CO2 and temp peaks seem to track each other
    2/ The period between past events seems to suggest the current event is around due
    3/ past temp peaks seem to be about where we currently are…


    Comment by chris — 5 December 2009 @ 1:07 PM

    Apparently we’re back in Climate Change Kindergarten.

    Why don’t I believe the proof of global warming? One reason is the data that exists to create the models.

    Yes, because the climate models are ALL WE HAVE!

    The ice all over the planet isn’t melting.

    The permafrost isn’t melting.

    The sea floor clathrates aren’t melting.

    Creatures and their habitats aren’t getting out of sync.

    The Jet Stream isn’t migrating northward.

    There isn’t a 2:1 ratio of record warm temperatures to record cold temperatures.

    There are no island nations threatened by inundation.

    CO2 does not have a greenhouse effect.

    Desertification is not spreading.

    Glaciers are not speeding up in various places.

    CO2 is not now higher than at any time during any part of the glacial/inter-glacial era, i.e. over 300 ppm.

    No extinctions are happening, and certainly not at an alarming rate.

    The intensity of weather phenomena like droughts, storms, floods are not increasing.

    Animals, plants, etc. are not moving to higher latitudes or higher elevations.


  14. 264
    Balazs Fekete says:

    This essay definitely hits important points that are further elaborated in the follow-up postings, but ultimately misses the point why global warming is so fiercely debated. First let’s realize that not only science is not binary (“settled” or “unsettled”) but the opposition to AGW has gradients too. On one end of the spectrum are those who flatly reject the idea of humans causing global warming, and the other end are those, who recognize human’s responsibility in recent global warming, but doubts if it warrants immediate actions.
    The next question in the spectrum of accepting or denying scientific theories is what we can do with it. I guess the primary reason for nobody disputing Newton’s gravity is that engineers can use this theory comfortably to design houses and bridges that don’t collapse. Scientists and engineers also found ways to deal with “know unknowns” (to borrow for Donald Rumsfeld) reasonable well, which is the primary basis for managing risks of floods or other disasters.

    The core problem of AGW is that we don’t know, where we are heading and what would we avoid if we took the suggested actions. AGW proponent are claiming that there is a tipping point, a point of no return, but they can’t tell, where is that point and where we end up if we pass that point, but vehemently argue that we have to avoid passing that point. Evidently, if global warming leads us turning our planet into Venus (with runaway greenhouse) or Mars (practically without greenhouse effect) that would worth everything to prevent. If global warming leads us to an ice-free world just like when dinosaurs roamed “happily” or a world with some ice but truly green Greenland than we might be less concerned.

    At first glance the elevated awareness about global warming was appealing since it seemed to point to the right direction in achieving sustainability even if it was for the wrong reason. Undoubtedly, there are plenty of reasons to move beyond the borrowed energy from the past and replace the inevitably finite fossil fuels resources with renewable energy, but at some point the climate debate went horribly wrong. The cap-and-trade agreement to curb carbon emission is likely to be a big scam. I can’t wait to hear reports of corrupt scientist providing bogus “evidences” to phony carbon sequestration projects to cash in “carbon credits”. The push for bio fuels is likely to be more destructive to ecosystem than anything humans did in the past. Signs like “another environmentalist for nuclear power” seems to be more concerning than global warming. AGW proponents owe the rest of us, what would any of the proposed arbitrary carbon emission caps will buy. Will it let us to prevent passing any of the imaginary tipping points or just merely delay reaching the climate nirvana of an ice free world, where the dream North-West passage is navigable all year around.

    AGW proponent like to paint the energy industry as the big corporations, which spread false claims to secure their profits. I highly doubt energy companies actually care. There is no way renewable energy will overtake fossil fuels anytime soon and their profits are safe regardless of the outcome of the upcoming meeting in Copenhagen. It is enough to compare, how far one can get with the 6 pound battery in a car compared to the same amount of gasoline. There is a big difference between energy and tobacco. While people can live without tobacco, comfortable life is not possible without energy. Substantial reduction of carbon emission would need to go far beyond changing lightbulbs or riding bicycles that not many of us is willing to take without clear explanation why it is needed.

    Perhaps the biggest mistake of all that the scientific community made in the last two decades was shying away to push for more monitoring. I have been sitting on various WMO meetings for almost a decade primarily focusing on the state of monitoring river discharge (which is perhaps the most accurately measured element of the water cycle). I have been telling WMO representatives that they should pursue more aggressively the need to operate adequate monitoring. I argued at every single meeting that just like most of us beyond certain age start to visit the doctors more often for regular checkup, the scientific community should have taken a closer look at the state of Earth observation and design strategies for adequate monitoring if we are worried about its current health. The first IPCC report almost two decades ago claimed that the observational records are too short to show warming trends with statistical certainties. Twenty years later our records are not much longer and we witnessed a steady decline (both ground based and satellites). While NASA and ESA are busy pursuing new “research” missions well established programs like Landsat are in constant jeopardy. At a meeting earlier this year, I talked to Kevin “travesty” Trenberth (from NCAR) and described that the current state of global warming is like a doctor who shows a plastic dummy to his patient explaining it has signs of an imminent heart attack and use that as an evidence to talk the patient to go through by-pass surgery without even taking an X-ray.

  15. 265
    Chris says:

    I don’t understand what the problem is. If people think that the climatologists’ statistical and modelling techniques were spurious, why not just invite in a group of computer programmers and statisticians to review the work? Then they’ll give their honest assessment, and the climate skeptics won’t have a leg to stand on, will they?

    So just let the math people see the whole code, they’ll exonerate you. Where’s the problem?

    [Response: They can already look at the GISS ModelE code or NCAR CCSM code, but your faith in the ability of mathematicians to work out what is going in a model of the climate system is I think rather optimistic. The issue is not the mathematical correctness of the code, but rather the appropriateness of the model to the real world. – gavin]

  16. 266
    Mike M says:


    “If you think this paper is “falsifying the credibility” you either haven’t actually read it, or don’t understand the math”

    You’re right about that paper, i included it in error – my bad – apolologies.

    However that paper does not validate GCMs, so it is of no use if you are attempting to argue the predictive ability of GCMs.

  17. 267
    Mike says:

    Re 199, 256 Dick

    I’m no expert but here are some thoughts.
    Temperature measurements are made of both the atmosphere and the ocean, including the Argo network, which measures ocean temperature at the surface and at depth.
    But you are correct that there is a lot of inter-annual variability in the temperatures due to ENSO and other factors.

    Studies of the earth’s energy balance show that the Earth’s heat content has continued to rise since 1998. John Cook over at Skeptical science has a good explanation of the published literature.

  18. 268
    Deech56 says:

    RE Jim Ogden

    Rasmussen says “Fifty-nine percent (59%) of Americans say it’s at least somewhat likely that some scientists have falsified research data to support their own theories and beliefs about global warming.” You need need to be contrite, not flippant. You need to get out in front of this publicly. The public doesn’t read this website. Your profession is under siege. You are probably a fine, honest scientist.

    What is Gavin supposed to be contrite about? If people believe something for which there is no evidence, isn’t it important to speak the truth instead of issuing apologies for something they are not doing? The scientists have been out there and Gavin has spent a great deal of time here responding to critics, but the scientists do not control the media.

    BTW, when “under siege”, circling the wagons may be an appropriate response. Just sayin’.

  19. 269
    Bill D says:

    Reviews of scientific manuscripts are just about never about whether the math is correct or whether the data are “fake.” I’ve reviewed or edited over 500 manuscripts for over 30 journals in my career, and neither of these issues has ever been a factor (I need to keep tallies for my annual reports). Instead, reviews focus on how well the data support the conclusions and whether a paper provides new “anything new.” Quite often the statistical analysis is critcized and quite often authors are required to highlight uncertainties in their analysis.

    In general, reviewers do not have the time to review the raw data and to reconstruct the original analysis. Reviewers need to have a degree of trust in the competence and honesty of authors. Verifying raw data is not really feasible or possible. A cynic will first request data in a computer file (and in recent years more and more supplementary data are being supplied in on line appendices). If the data file is not to be believed what is the next step? Please sent notorized copies of your lab note books (?) The biggest uncertainty about studies in my field (ecology) is not whether the results are “valid” but how broadly they can be generalized to nature. This is where a discussion of results and their relevance to the current literature is especially important. Good studies help explain uncertainties and apparent contradictions in the literature

  20. 270
    Jim Cross says:

    Okay, the nature of science is that it is never really “settled”.

    So, if we are 90% certain temperatures will rise 2-4 degrees without changes in human activity based upon current science, where does this leave us with mitigating actions?

    The problem is there uncertainty in mitigating actions. Will governments really enforce changes? Will the changes have the desired effect? Will unexpected growth in China or India undo whatever the industrialized countries do? Will Greenland melt or not? Will a super volcano or series of big ones upset the calculations?

    Once you multiply up the other uncertainties, you are left with something very unsettled – which is the problem.

  21. 271
    Theo Hopkins says:

    What about the factoid that has been wandering around the blogosphere and media that “‘Global Warming’ has been deliberatley morphed into ‘Climate Change'”? Sceptics delight in saying this.

    The origin, or rather lack of origin of, “The science is settled” has been well covered here, and I thank posters for the useful, and usable, comments or links.

    However, I would be grateful if someone could point to when this expression “climate change” first came into public use.

    Clearly it was being used when the first IPCC was set up in 1986(quite some time ago!) – but before that, when was it first commonly used?

  22. 272
    Dick Veldkamp says:

    Steady warming of the Earth?

    Mike (#267) Thanks for your input, very useful link. The upshot seem to be that my understanding was correct (#199). I need to study the references some more though.

    David (#256) You (or Barton) wouldn’t happen to remember in which thread BPL’s nalysis is?

  23. 273
    SecularAnimist says:

    Walter Manny wrote: “I would argue that this business of calling people “deniers” is unfair and unreasonable to ANYONE. The term is clearly used in reference to the Holocaust to imply that skepticism regarding AGW theory is tantamount to Ahmadinejad’s rantings.”

    To be quite clear, when I personally use the term “denier” in reference to those who deny the existence of dangerous anthropogenic global warming, I intend an explicit allusion to Holocaust deniers.

    The difference being that global warming deniers are worse, for one simple reason: Holocaust deniers will not cause any more people to be killed in the Holocaust by denying that it occurred, but global warming deniers contribute to causing suffering and death for many millions of people, far more than suffered and died in the Holocaust and all the wars of the 20th century combined, to the extent that their denial and deceit delays and obstructs the urgent action needed to phase out GHG emissions.

    Indeed, by successfully delaying action for a couple of decades already, the AGW deniers have already caused suffering and death for millions, which could have been prevented had we taken appropriate action when we first understood the nature of the problem. There are people needlessly dying right now, this very minute, and many more whose needless deaths are now assured, as a direct result of the world’s failure to act on this problem for a whole generation.

    And as for implying that “skepticism regarding AGW theory is tantamount to Ahmadinejad’s rantings”, it is the AGW deniers who have blackened the name of “skepticism” by dishonestly appropriating that term as a facade for their financially and/or ideologically driven dishonesty and arrogant, belligerent ignorance.

    And it is the rhetoric from the deniers about a supposed “global conspiracy of climate scientists” in cahoots with “liberals” to control us all that has sickening echoes of the anti-Semitic scapegoating rants of Ahmadinejad and like-minded dictators.

  24. 274
    Bill D says:

    Although the scientists who run this site have made important conntributions to climate issues, some “skeptics” here have a very limited view of the strength and volume of publication in this field. Schmidt and Mann are making important contributions, but climate science is a large group effort. How many climae papers are published each year? One might count up the number of climate journals and then add a percentage to account for climate papers published in general journals. Perhaps the number of publications is 500 or 1,000 or 2,000 per year.(?) This represents an enormous amount of data collected, analyzed by many scientists. The evidence is not based on a few scientists whose papers might be reviewed and vetted by computer scientists or retired statisticians.

  25. 275
    Cremenoire says:

    About dualism

    Dualistic mode of thinking is no great friend, especially in science.
    The “either this or that” leads to correlations magically turning to causations: so if Venus is bright and that star is bright, than Venus must be star. Well, they are both bright objects but it doesn’t imply that what is causing them to be bright is the same.

    What about absolutism?

    That’s another problem, and for many climate deniers it is the tool of choice. To take one infinitely small flaw in a well-built hypothesis and bring to whole edifice down. If one of the bricks is yellow instead of red, then the house must be condemned. So let’s go back to Venus.

    Let’s assume that Venus is not a star because:
    – it is way too small to be a star according to nuclear fusion process requirements, measuring its mass through Newton’s third law
    -it does not emit solar particles
    -it has a solid rocky surface
    -it does not have a solar surface temperature (here; Venus; 500C)
    -it is not at the center of our solar system
    -as close as it is from the Earth, it would turn nights in days

    We could go on and on. I think it’s pretty well accepted that Venus isn’t a star. But let’s suppose that some Venus planet deniers would come up with the following point:

    Well the Russians got their satellite there, but it collapsed so that doesn’t count. But in all cases, we have never been to the core, therefore there is no way whatsever we can absolutly be sure there is no fusion.

    That’s the whole point. We can never be absolutely certain in science. But we build framework of interpretation one can metaphorically see as a house or a building to improve our understanding.

    Absolutism and dualism are no good pals to anyone.

  26. 276

    Mike M to Gavin: Why do you continue to wriggle about the lack of validity of climate models?

    BPL: Probably because Gavin is a climate modeler himeslf and knows that the lack of validity you describe exists mostly in your mind. Read and learn:

  27. 277

    Rod B: Rush Limbaugh is a creation of Ailes?? Limbaugh called for execution of climate scientists???? Can you back that up??


    Rush Limbaugh is a creation of Ailes

    “In 1991, Ailes convinced a syndicator to bring Rush Limbaugh from radio to television and became executive producer of the late-night show.” –Wikipedia entry on “Roger Ailes.”

    “Rush and Roger Ailes Speak at Boy Scouts Awards Dinner
    November 11, 2009” –Rush Limbaugh’s web site

    “The executive producer of Limbaugh’s TV show, Roger Ailes (a Republican campaign consultant and president of the CNBC cable network), didn’t claim that his star had debunked the rumor–he boasted that Limbaugh’s report of “a suicide coverup, possibly murder” was a scoop.” -“Koppel Covers for Limbaugh’s Rumor-Mongering,”, accessed 12/06/2009.

    Limbaugh called for execution of climate scientists

    Limbaugh: Scientists involved in global warming “hoax” should be “named and fired, drawn and quartered, or whatever it is.” -The Rush Limbaugh Show, 11/24/2009.

    Breitbart: “Capital punishment for Dr James Hansen. Climategate is high treason” -Twittered by Andrew Breitbart, 11/29/2009.

    Did you think I was making it up?

  28. 278

    chris: As a previously uninterested simple tax payer my first question is where are the long term analysis for temp & co2?

    BPL: Try here:

  29. 279

    Brian: If there existed data going back a million years, made with tons of accurate thermometers placed all over the world–in the oceans and in the air, then I’m inclined to believe it is possible to model the future of the world’s weather accurately, given that we also understand what caused temperature fluctuations during those past years. But, my understanding is that we don’t have that data.

    BPL: Google the following terms:

    ice cores
    palynology (NB: This is nothing to do with Sarah Palin)

  30. 280

    Krumhorn: Great! So Gerlich and Tscheuschner are “cranks”. Isn’t that precisely the attitude revealed in the climategate emails that has turned so many heads to look crab-eyed at ‘climate scientists’?

    Terms like ‘deniers’ and ‘cranks’ aren’t winning you any friends, and it’s precisely that kind of snotty arrogance that has brought you to this sad place.

    BPL: Gerlich and Tscheuschner are pseudoscientists, or at least their most famous paper is a work of pseudoscience. They misstate the second law of thermodynamics, a scientific generalization that is very well understood, and base their conclusions on their misstatement. That is the act of a crank. Deal with it.

  31. 281

    Jim Ogden: You need need to be contrite, not flippant.

    BPL: What do climate scientists need to be contrite ABOUT, precisely? “Contrite” implies they did something wrong, transgressed the moral code, committed a crime. Care to give details?

    If the crime is “suppressing data,” it didn’t happen.
    If it is “destroying original data,” that didn’t happen either.
    If it is “illegally blocking FOI requests,” that didn’t happen either.

    So what do they have to be contrite about? The fact that 59% of Americans think they’re frauds? I’m sure there was a time, and not so long ago, that 59% of Americans thought blacks were less intelligent than whites. Majority vote doesn’t determine truth.

  32. 282
    Steve Fish says:

    Comment by ghost — 5 December 2009 @ 8:45 AM

    If I may paraphrase the post — Where’s the beef?

    Insubstantial dead person:

    Excellent logic! All denial groups (e.g. evolution, holocaust, or the fake moon landings) mostly tear down the arguments of others while rarely producing anything new. I don’t think you will have to defend your statement in this, rather empty, denial idea space.

    The only legitimate refutation of an established scientific theory that already explains a majority of the data, is a better one that elaborates new information AND also explains already existing data.


  33. 283
    carl says:

    has anyone here yet on any of these threads posted all the emails and code from the stolen/hacked CRU stuff?

    seems to me if not maybe they should be, a little sunlight would do wonders to dispel any myths there may be

    not sure if the major media can due to possible legal issues but as of yet I haven’y seen any do so

  34. 284
    Steve Fish says:

    Comment by Mike M — 5 December 2009 @ 9:02 AM:

    I think your admonition to Gavin suggesting that he continues “to wriggle about the lack of validity of climate models..,” is more than a bit an overstatement. I checked your first reference and it was a “Rapid Communication” in a hydrology journal that checked to see if global climate models could be used to predict precipitation in 8 individual stations in various parts of the world. As global climate models don’t pretend to predict on this scale, the findings of the study are not surprising. I am pretty sure that the authors would agree. Because this one example is very inappropriate in relation to the “wriggle” comment, anything else you say on the subject is suspect.

    Just in the case that you are not just trolling this site, why don’t you spend some time to study this topic in order to avoid the embarrassment of inappropriate posts?


  35. 285
    Steve Fish says:

    Barton Paul Levenson — 5 December 2009 @ 10:25 AM:

    Your belief system is very (very) different from mine, but when it comes to accurate (non professional) climate information, you are the man!


  36. 286
    Rod B says:

    BPL (277), I still don’t buy the Limbaugh quote — misquoting Rush has become something of a national pastime; Hell, Reid even does it on the floor of the Senate! However, I can’t explicitly refute it nor am I inclined to spend the time chasing it down.

    I didn’t say anything about Breitbart; I don’t even know who he is. If that’s what he said, he’s an idiot — even if part of it (the treason part) does sound close to what Hanson said before Congress.

    A minor point, but your backup support for claiming Ailes created Limbaugh, did no such thing. If you had said (as your rebuttal did) Ailes initiated and produced Rush’s TV show, that would have been accurate, but just would not have had the zing and ring of “creation”!

  37. 287
    Chris says:

    “The issue is not the mathematical correctness of the code, but rather the appropriateness of the model to the real world. – gavin”

    I don’t understand – how can a model be appropriate for the real world, but not mathematically correct? I would assume mathematical correctness is antecedant – that mathematical correctness must be shown before we can say if a model reflects the real world. Is this wrong?

    [Response: Other way round. Mathematical correctness is not a demonstration of relevance. – gavin]

  38. 288
    Jimbo says:

    CO2 can be so toxic. Just don’t tell the vegetation.

    “Greenhouse gas carbon dioxide ramps up aspen growth” “…elevated levels of atmospheric carbon dioxide during the past 50 years have boosted aspen growth rates by an astonishing 50 percent.”

  39. 289
    Dick Veldkamp says:

    Re 271 Theo Hopkins

    I seem to recall that the term ‘climate change’ is an invention of the deniers. They brought it up because it sounds less alarming than ‘global warming’ (‘climate has always been changing, so there’s nothing special happening now’). I think it is in that infamous memo from some communication strategist (sorry, can’t remember the name just now), in which it is argued that the deniers cannot win the debate using facts, but they should focus on ‘the science isn’t settled’ instead.

    Searching for presentations by Naomi Oreskes is probably be a good start to find the reference.

  40. 290
    Mike says:

    Re your Response: No. The standard range is well supported by paleo-climate studies and a small sensitivity is not. Lindzen’s latest paper will not turn out to be robust (I predict), and even Roy Spencer has said he can’t get the same results with only modest differences in approach. You might like to think that a single paper from Lindzen overturns everything, but it doesn’t.

    But as Einstein said – No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

    So, given the right paper and argument I think it does only take one. It’s called science.

    [Response: You are playing games. There are many papers using different approaches that give numbers around 3 deg C, there is one new one that gives a smaller number. There is clearly a mismatch. So you need to explain why all of the others are wrong if you except the new one. Or explain why the new one is wrong. The amount of work in the latter case is clearly going to be less, and so my Bayesian prior is that the Lindzen paper will turn out not to be robust. Feel free to come back in six months to hold me to my prediction. – gavin]

  41. 291
    Matthew L. says:

    As I have stated here previously I think much of the problem is that the science of prediction that is required here will never be ‘settled’ until the prediction becomes history.

    The least we can do is to make sure that the history we do have is as well documented as possible. We are being asked by our political representatives to make huge life-changing decisions on replacing fossil fuels as our primary energy source. The massive cost in technological research and productive effort required on energy conservation and to replace those fuels with non-fossil sources will require a herculean physical and financial effort from every government and individual the world over.

    From the posts on this blog it seems we cannot even agree what has happened over the last decade, let alone the last 150 years.

    For a start, is it possible to state that the most accurate (or at least consistent) measurement of the temperature of the lower troposphere is available from satellites? It also seems to require less adjustment than the surface record and it is the extent of adjustments that seems to be creating most heat around this leak. If the satellite record is recording the trend accurately, then surely we can stop arguing at least about what has happened since 1979?

    One good thing that might come out of all this is political pressure on Government met offices to release data, and maybe to create a single repository for all the basic raw temperature data available including the temperature series, grid reference, and altitude of each weather station. Once this is available it will then be possible to propose adjustments for technological changes, urban heat island etc.

    I am sure even that will not ‘settle’ the arguments once and for all, but it should at least dampen some of the accusations of cover-up and fudge.

    Short update on where I have got to. I now have quite a good grasp of the greenhouse gas forcing effect of CO2 on air temperatures in the lower troposphere (for a layman!). I have also read widely enough to know that the only real argument amongst legitimate scientists is not whether anthropogenic global warming will happen, but how much. This is dependent mainly on how the various positive and negative feedback effects work to effect the temperature of the lower troposphere.

    The consensus seems to be that the positive effects will dominate and we can expect a 3 – 6 deg K temperature change resulting from an initial 1 – 2 deg K forcing from CO2. If the feedbacks cancel out we could probably cope with a circa 2 deg change in temperatures over 100 years. But if the positive feedbacks dominate and 6 deg change results, we are all doomed.

    Such a massively wide variation in potential outcomes between ‘cope’ and ‘doom’ makes it very difficult to create political consensus on the actions needed.

    One of the few ‘real’ scientists out there with any kind of coherent argument against the positive feedback effect is Roy Spencer. Being one of the gatekeepers of the satellite temperature record, he seems to be the one sceptic worth at least listening to.

    In his 6 December blog entry he outlines his theory that he has found a fundamental flaw in the way current methods quantify feedbacks from the historical data and the way this is coped with in climate models. Most of this goes way over my head but I am hoping that his presentation due on 16 December might prompt a discussion that would help me to clarify the issues.

    Thanks for keeping this blog commentary so open, Gavin, and your efforts to moderate the discussion. It is good to hear both sides of the argument in one place rather than have to jump around between pro and anti sites.

  42. 292
    Brian Dodge says:

    Have Gerlich and Tscheuschner published a retraction, or admitted they wrote the paper as a prank? Neither action would do much for their careers – maybe they could finesse it, by publishing a retraction(so they wouldn’t be seen as pranksters lacking the judgment not to know where it’s OK to make fun of/embarass your peers(emails,blogs yes – costly journals, no)), while contritely telling their colleagues it was a prank that they’re sorry went too far(so they wouldn’t be seen as complete idiots). Or maybe they can just lay low, hope people forget about it, and in the meantime work quietly and anonymously for Exxon/Mobil, or join CFACT (

  43. 293
    Ron R. says:

    I’ve read I think three WSJ articles recently on the issue. In each case the article was scurrilous the author anonymous and the ability to comment turned off. That makes the WSJ little better than Hearst tabloid yellow journalism IMO. In one case though there was a name only on the comment page (switched off), the smirking face of one Gordon Crovitz.

  44. 294
    Jim Bouldin says:

    Daniel J. Lunt, Alan M. Haywood, Gavin A. Schmidt, Ulrich Salzmann, Paul J. Valdes & Harry J. Dowsett:

    Earth system sensitivity inferred from Pliocene modelling and data.

    Nature Geoscience, Published online: 6 December 2009, doi:10.1038/ngeo706


    Quantifying the equilibrium response of global temperatures to an increase in atmospheric carbon dioxide concentrations is one of the cornerstones of climate research. Components of the Earth’s climate system that vary over long timescales, such as ice sheets and vegetation, could have an important effect on this temperature sensitivity, but have often been neglected. Here we use a coupled atmosphere–ocean general circulation model to simulate the climate of the mid-Pliocene warm period (about three million years ago), and analyse the forcings and feedbacks that contributed to the relatively warm temperatures. Furthermore, we compare our simulation with proxy records of mid-Pliocene sea surface temperature. Taking these lines of evidence together, we estimate that the response of the Earth system to elevated atmospheric carbon dioxide concentrations is 30–50% greater than the response based on those fast-adjusting components of the climate system that are used traditionally to estimate climate sensitivity. We conclude that targets for the long-term stabilization of atmospheric greenhouse-gas concentrations aimed at preventing a dangerous human interference with the climate system should take into account this higher sensitivity of the Earth system.

  45. 295
    Yoda says:


    I really like your analogy of the “construction of a building”. I too view science, inlcuding the subject of debate, as adding a “brick” to the building. Of course, orginally the “building” was designed and as the shape of the building takes form, the view becomes more obvious as to the “quality” of the orginal design. Such metaphors are well understood for so many of us scientists and engineers who know God.

  46. 296
    Bryan S says:

    Since Eric Steig shut down comments on the thread “Who you gonna call?” I reproduce the informative discussion in here hopes that the moderators will post.

    Gavin Schmidt writes: [Response: “I’ve stated that I advocate for the proper appreciation of climate science and against it’s abuse in political arguments, but RPJr has decided arbitrarily that this is somehow impossible and that I’m advocating for something else (also undefined). Maybe I’m naive, but I feel that education outside of classroom is still worthwhile”-Gavin Schmidt

    Bryan S comments:
    “Only you know if this is true Gavin. The only thing the rest of the rest of us can judge you on are your actions, not just your words. When you choose to appear with a group of blatant political operatives who clearly advocate Keynesian-type economic policy, it is not “arbitrary” that some might conclude that you concur with their policy recommendations. Clearly, the fact that a particular political action group is willing to sponsor your appearance serves as compelling evidence that *they* themselves have made the judgement that you will help bolster their political advocacy. Gavin, surely you are not so naive as to fail to realize that when you appear in these types of forums, your claim to political neutrality is compromised (fairly or unfairly). You can’t bash Limbaugh or however, then appear on a platform with the other side of the political spectrum, and still maintain your claim to political indifference. That will not fly with the public. You have willingly offered yourself as a public intellectual on the issue of climate change, and like it or not, it is high time you wise up about how to operate effectively in this arena.
    P.S. please post this comment, and I would sincerely appreciate a serious response
    Thanks, Bryan”

    Eric Steig responds to Bryan S:
    [Response: I don’t see the contradiction here. First, the fact that any particular group likes what RC has to say doesn’t say anything about RC’s politics. Second, Limbaugh (for example) abuses science in political arguments and if any of us have ‘bashed’ him, that is the only reason why. Third, this post — by me, not Gavin — is complaining about someone who is identified as a liberal by most! Fourth, I’m aware of nothing negative we’ve said about any conservatives — or anyone else — who present the science honestly. As for us being naive: yes, clearly we are naive. It never occurred to us — or at least not to me — that so many people were so intellectually bankrupt that they would resort to the tactics they are using now.–eric]

    Bryan S responds to Eric Steig:
    “Eric says: “First, the fact that any particular group likes what RC has to say doesn’t say anything about RC’s politics”-Eric
    Bryan S says: No, but when RealClimate (Gavin and Mike) choose to appear on their (a political advocacy group’s) platform in the midst of a political firestorm, and by inference, “Joe Public” draws the conclusion (rightly or wrongly) that RealClimate supports their (the think tank’s) political position, “Joe Public’s” conclusion is not “arbitrary” as Gavin stated. Quite to the contrary, it is supported by some pretty darn good circumstantial evidence, at least in the mind of Joe Public. That damages (rightly or wrongly) your claims of political neutrality, and compromises (in the mind of the public) your position as an honest broker of the science.

    Furthermore, RealClimate (at least all of its individual members that I have read) makes no bones that governments should compel immediate action from its citizenry and private enterprise to curb carbon emissions to combat dangerous climate change, whether through direct carbon taxation or other regulatory/hybrid government-free enterprise methods. Eric, that is a broad policy position reflecting a certain philosophy in political economy, just like arguing in favor of no regulation is also an opposing statement in political economy. Yes, your expert knowledge of the science may have informed that position, but please don’t try to argue that it is an a-political stance, and that RealClimate is indifferent to politics. You fool nobody.

    Finally, Gavin may not want to respond, but my request was for his views on this, since he is the one who chose to appear at the politically staged event a couple of days ago. Maybe he feels my question is not worth a response, but I really think a bunch of people might be interested in his comment.

    [Response: Read the transcript of the conference and see what I actually said. Pretty much the same thing I’ve said in other forums. I very rarely turn down a request to contribute a scientific perspective in whatever venue. But let’s imagine that the Cato Institute asked me to write a piece, or that the Republicans in the Senate asked me to testify about my research (neither things that have ever happened FWIW), would that imply that I was hopelessly compromised? – gavin]

  47. 297
    Jim Bouldin says:

    Of course, orginally the “building” was designed and as the shape of the building takes form, the view becomes more obvious as to the “quality” of the original design

    Uh, that’s not what he meant with the analogy. He was referring to the fact that scientific knowledge comes predominantly in small increments, just like the growth in size of a building. Regarding some “original building design” the analogy fails utterly.

  48. 298
    Neil B ♪ says:

    This is a good place to offer the following for rebuttals if anyone bugs you about “Climategate.” (Sadly, appreciating rebuttals takes intelligence and admitting to them takes honesty …):

    1. The modern theory of AGW (increasing CO2 absorbs more IR and leads to warmer temperatures) was laid out way back in 1896 in a notable paper by future Nobel Prize winner Svante Arrhenius. He wasn’t promoting statism or to be a flunky for Al Gore; indeed SA thought the warming would be beneficial – so he didn’t promote the theory to scare people.

    2. Even in a case of actual cheating and cover-up, or even fabrication don’t disprove an idea itself. Look at prosecutors “framing guilty men” by “improving” evidence to ensure conviction, look at the Piltdown hoax which sure doesn’t mean evolution is false and other evidence couldn’t be rounded up. (BTW what CRU did wasn’t even that bad anyway, this just emphasizes the irrelevancy of ad hominem issues to the material point. In my bitter experience conservatives are very into projecting from personal factors onto imagined objective ones.)

    3. CO2 is a stimulus similar to lowering interest rates are for an economy: the effect is not direct and linear, there are variations and other influences. Tell someone who says, “how come it got cooler during the last ten years” (it may not have, but play along here): How come we had a cool spell e.g. during April, before summer came along? Does that make you doubt the idea that changing axis angle causes seasons?!

    4. Most of the things we would do to lower CO2 are good for the economy and national interest anyway: save money on gas and other non-renewables, reduce dependency on other nations (including Muslim ones, conservartives!), it will run out anyway in decades to centuries, etc.

    5. An effect doesn’t have to be “certain” or uniformly and highly damaging to be worth trying to avoid anyway – what about terrorist threats, the irony of Cheney et al’s “One percent doctrine” etc.

    6. The skeptics and doubters are way more dishonest and controlled by money interests.

  49. 299
    Hank Roberts says:

    Gavin, I suggest my favorite analogy is better.

    Science grows like kudzu–it’s not like a building or a wall, nor like a mighty oak with a single deep taproot.

    Science grows at the new ends, in all directions, creating fresh new roots as well as new leaves and flowers, wherever it finds a chance. It leaves its origins behind.

  50. 300
    Lynn Vincentnathan says:

    Well, here’s something that’s unsettled — how agriculture in higher latitudes is going to be affected by GW (& increased CO2).

    This is actually in response to #98 on “Who You Gonna Call?”:

    Will you get equal credit for Siberia and Canada coming more online as crop producing countries?

    There are tons of issues here, not to mention negative impacts from CO2 — it diminishing, if not cancelling out altogether carbon fertilization — such as by lower crop nutrition, lower productivity from floret harm to rice, more pest & weed damage as C3 weeds do better than C4 crops (and the need for more pesticides), and increasing plant toxicity, just to mention the iceberg’s tip on negative CO2 effects (and what about all that seafood being harmed by ocean acidification — Exxon may call CO2 life, but it could also spell death).

    Okay, onto the more specifically GW issues, such as longer growing seasons, but think of the heat stress in mid-summer right in the middle of the growing season from superhot (and long) days, increased flooding that can wipe out crops altogether, & flooding amidst drought, since warm air holds more moisture, sucking it up out of the soil and plants. And did I mention that the soil is a lot poorer up in the arctic region (personal communication from someone who actually lives up there). And if you have a globe, you will notice there is not as much land as it looks like on a map. Think of Greenland, it’s not only much smaller than it appears on a map, but once melted I read somewhere it will be like an atoll around a huge lake…not as much land there for farming as one might imagine on first glance.

    Scientists predict that there will be greater agricultural productivity in the higher northern latitutdes up until about 2050, after which there will be a sharp decline due to GW and its effects.

    But the science isn’t really settled….the decline could start much sooner. And I’m just wondering if they’ve figured in ALL the factors and if there really will be any increase at all, or if they even know at present what all the factors are.

    Sort of reminds me of the peace dividend after the cold war collapse that was supposed to make our nation rich. Or nuclear power that would be too cheap to meter.