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  1. Thanks, I am looking forward for your comments to the chapters.

    Comment by Scaramanga — 29 Apr 2007 @ 12:20 PM

  2. IPCC missed the opportunity again! What is Climate? A question which should not be ignored when going through the full Report. It is interesting to see what IPCC can do with the term: CLIMATE. That the term climate is used demonstrates the new Technical Summary, AR4WG1_TS, which states on page 21, that: “The Earth’s global mean climate is determined by incoming energy from the Sun and by properties from the Earth”. But IPCC has never even tried to define the term. As part of WMO and UNEP it is also responsible for the UN Framework Convention on Climate Change, which did not define the term at all, but referes instead to: Climate Change, and Climate System. While one can only wonder to read in the FCCC that: Climate change means the change of climate…; the new Policy Summary is just introducing its own understanding: Climate change in IPCC usage refers to any change in climate over time, whether due to natural variability or as a result of human activity. (see Footnote 1, of the SPM-Report).
    It should to be not so difficult for IPCC to realise that one can not define climate change if climate has not been defined in the first place. Further papers discussing this question since 1992, e.g. Sea Law Inst., 1994, or Nature 360, p.292 (1992) on: http://www.oceanclimate.de. Many thanks for making the TS available so quickly.

    Comment by arnd — 29 Apr 2007 @ 2:00 PM

  3. Thanks, just like to mentione that a WIKI as a quick reference is always more handy than those pdf’s. Also the content is even more accessable.

    A quick summary maybe even a speaken youtube video would be great for educational purpose.

    Cheers

    Comment by saveEarth — 29 Apr 2007 @ 2:14 PM

  4. Gavin, your approach is sound. The only cautionary would be that where there is not incontrovertible evidence for conclusions reached, that you bring forward, exhaustively, counter-arguments, and when, having done that, you also state, in non-technical language, why you think that particular conclusion may have over-reached and try, in effect, not to negate that majority conclusion but to raise some reasonable doubt about it no matter how many scientists in your area of expertise may disagree with you. Doubt, after all, is the beginning of knowledge. I look forward to your discussions. Thanks for your efforts. My approach, basically, is the medical one, because even if there may be uncertainty, we must take care to always err on the side of caution as the planet itself is the patient.

    Comment by Vern Johnson — 29 Apr 2007 @ 2:21 PM

  5. I believe that there is a entire document dedicated to how to mitigate climate change and I personally would like Scientists to comment on this subject. I know that RC are not energy scientists but maybe they can get a few of them to write an article for RC because from what I can tell and from what I have read the entire situation is a big mess strategically and a lot of the technology being pushed seems premature anc could even make climate change worse. We need some clarity on the matter. Maybe RC will comment on these matters now that the debate on climate change is becomming old and worn.

    Comment by pete best — 29 Apr 2007 @ 2:35 PM

  6. Well, if you are going to be covering this in depth, I will be sure to set aside some time for it. I would certainly like to learn more, particularly if you take it slow so that I can digest. And what the heck – it will give some more purpose to my life. The first moral obligation of anyone human is to understand. We will see what happens after that.

    Thank you!

    Comment by Timothy Chase — 29 Apr 2007 @ 3:16 PM

  7. RE#5, pete we can at least try and break the complicated topic of enegy supply and energy technologies down into a couple of categories:

    1. Already existing technology: Wind turbines, solar thermal systems, solar photovoltaic systems, fuel-efficient hybrids, ethanol and biodiesel from crops (which can be used in existing diesel and gasoline engines).

    2. “Dead-end” carbon-neutral technology – for example, nuclear and hydropower. Dams silt up and nuclear is not a long term soultion (waste disposal, limited fuel, and high cost of dealing with aging nuclear power plants).

    3. Future technologies that need R&D: high-efficiency photovoltaics (say, 50% conversion) (as well as lowering the cost of PV), energy storage systems for intermittent sources like solar and wind (hydrogen storage, other methods), advances in biofuel technology (for example, hydrogen production from algae, cellulosic ethanol, etc.)

    4. Identifying where fossil fuel reductions can be made – #1 is in agricultural production. Massive amounts of fossil fuel are used in industrial agriculture, from diesel for machinery to natural gas for fertilizers and herbicides to the fuel used for long-distance transport and refrigeration. #2 is in transportation, from airlines to cars to ships to trains. Electric vehicles that use solar and wind for energy are one example. One airline company is experimenting with new biofuels for airplanes (biodiesel won’t work as it freezes at altitude).

    The important thing is to convince governments to get behind such plans, and to convince individuals to use less energy. The existing value of fossil fuel infrastructure is estimated at something like $10 trillion dollars, and that needs to be replaced by renewable energy infrastructure. That does seem like a very large amount of money, but in comparison to other recent expenditures it isn’t so large.

    Still, there’s a huge gap that needs to be filled. For example, the amount of renewable energy research that is carried out in US universities is miniscule compared to the amount of pharmaceutical research that goes on (i.e. the entire NIH budget, more or less). A 1000-fold increase in funding for renewable energy research would be a good first step.

    Comment by Ike Solem — 29 Apr 2007 @ 3:33 PM

  8. Re #5 & #7, I also feel this is becoming a critical part of the whole debate, though we still need to advance the climate science.

    Much of the fear uncertainty & doubt (and downright bullshit) that has mainly left the climate arena is well entrenched in the energy debate, and is more likely to stay there due to the much greater commercial interest.

    We very definitely need a partisan but scientific viewpoint expressed by experts in the field (as RC has been doing – thank you).

    Comment by AlBreingan — 29 Apr 2007 @ 5:35 PM

  9. Re #5, #7 & #8: Perhaps we need a sister website called RealClimateSolutions that is run by energy engineers. I for one am watching the various low-emission energy solutions with the will of a football fan desperately hoping to win the grand final – ” c’mon, score a goal, score a goal “. The greenhouse science is fascinating, but sooo depressing.

    My favorite teams at the moment are:
    * hot dry rock geothermal
    * solar tower technology (see animated rendition here )
    * Pelamis wave energy generators

    And of course all the energy efficiency technologies such as LED bulbs, and the various intelligent policy options that will be critical to driving down energy use.

    Don’t forget to boo the umpire when he unfairly favors opposition teams.

    Comment by Craig Allen — 29 Apr 2007 @ 6:46 PM

  10. Re: #2

    From the Third Assessment Report, Appendix I – Glossary:

    “Climate in a narrow sense is usually defined as the â��average weatherâ��, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.”

    A definition is clearly stated.

    Comment by Chris C — 29 Apr 2007 @ 6:46 PM

  11. Re #5, #7 & #8,

    Note that existing nuclear power plants in this country are lasting much longer than had been expected and new designs could be even better. They aren’t the ultimate solution, but they can be an important part of it for some time.

    While looking at the other energy sources and increasing efficiency in energy use, don’t ignore really creative solutions such as what the Heat Island Group at Berkeley have been working on: http://eetd.lbl.gov/HeatIsland/ . Better roofing materials can greatly reduce energy usage while directly reflecting more energy into space. They have many other ideas that are worth looking into.

    Comment by Bob Reiland — 29 Apr 2007 @ 7:04 PM

  12. Could you please respond to a news report from Dab Elliott of Denver, quoting William Gray, a Colorado State University researcher and hurricane forecaster, who has said that global warming is all down to ocean currents and will reverse itself within 10 years.
    The news article was headlined “Ocean currents to blame for warming: expert”.
    Has he submitted a paper on the subject for peer review by climate scientists? I’m actually assuming that the answer to my question is, No!

    Comment by Ron Tuckwell — 29 Apr 2007 @ 8:45 PM

  13. Is there any chance that the new IPCC reports will be put into html, like the 2001 reports are currently? (The pdfs are so slow – not that it isn’t worth the wait, but…)

    Comment by Pat — 29 Apr 2007 @ 10:10 PM

  14. Re # 4 [bring forward… counter-arguments, and…state…why you think that particular conclusion may have over-reached …to raise some reasonable doubt about it]

    Hmmm…sounds like you are already convinced that the report presents incorrect conclusions, and you want Gavin to do the skeptics’ work for them?
    What if Gavin agrees with the conclusions of the report?

    Comment by Chuck Booth — 29 Apr 2007 @ 10:25 PM

  15. Why am I tempted to respond to Chuck by asking if he wants to bet on that? Unless you can find a countervailing forcing opposite in sign to that of CO2, and Gray cannot (nor can Lindzen and he has been trying to decades) you cannot handwave accelerating global warming away. Increased greenhouse gases, principally CO2, are by far the largest forcing in the climate system today and are getting larger. It is the elephant in the room.

    Comment by Eli Rabett — 29 Apr 2007 @ 11:21 PM

  16. Re: #12
    William Gray’s wiki entry answers your questions. He has a hypothesis about thermohaline circulation being responsible for recent warming, and forecasts future cooling.

    Has has no peer reviewed papers on this ideas re GW (no surprise there) but claims to be ‘working on it’. He was renowned for his earlier work on hurricanes but seems to have gone off the rails a bit.

    Gray’s ideas have already been given the realclimate treatment.

    Comment by SCM — 29 Apr 2007 @ 11:34 PM

  17. RE #4 & 14, I’d like to see some mention of scientific studies and articles that didn’t make the cut off date for the IPCC (or were excluded on technicalities or the politics of trying to get everyone to agree), and how they might be showing things are even worse than the IPCC portrays.

    It’s not that I want it to be worse; I pray everyday GW is not real, or is not as serious as they say. It’s just that I have this niggling feeling that it may actually be or could be worse, and we need to know.

    Comment by Lynn Vincentnathan — 30 Apr 2007 @ 1:23 AM

  18. There is now a public understanding that global warming is real, and man-made, at least here in Italy. I suppose the reason is this IPCC report is so sound that objections are unreasonable. This does not imply, however, that average people understand all of what is going on.

    So I have a proposal for oceanographers and atmospheric scientists (and geologists, for that matter) who wish to do some spreading of recent scientific achievements. The proposal is to start contribute to the Citizendium ( http://en.citizendium.org/wiki/Main_Page ), which is sort of a wikipedia with an editorial system. Or, post in wikipedia.

    Think about that: when you look for a definition in Google, wikipedia or other wikis are almost always in the first page. People knowing nothing of, e.g., global warming, will end up learning about it from wikis, most probably. I believe posting in such wikis is a primary way to do scientific culture.

    Comment by Nereo Preto — 30 Apr 2007 @ 2:20 AM

  19. Re # 12 – Ron, see if this section from April last year helps.

    http://www.realclimate.org/index.php/archives/2006/04/gray-on-agw/

    Comment by Louis Hazard — 30 Apr 2007 @ 2:51 AM

  20. #12: roughly speaking, you can have two kinds of temperature variations: in one version the global heat content keeps unchanged, but the heat is redistributed differently, leading to changed temperature patterns. This is what happens when you have a very cold winter in, say, Russia. It is then warmer somewhere else, and the global average temperature doesn’t change.

    The other version shows an increase in the global heat content, due to greenhouse gases. There we have globally increasing average temperatures, including the oceans AND the atmosphere. This is what happens right now under the conditions of global warming.

    If global warming was due to warmer ocean currents, then this energy has to come from somewhere. Therefore, we should be able to find it in in the form of lower temperatures somewhere else (the deep ocean??), but we don’t. Therefore Gray should come up with some REALLY good explanation regarding his claim, but I doubt it will be convincing. As Eli said: Ask Gray to bet a few thousand dollars, and you’ll see whether he’s up to it.

    Comment by Nils Simon — 30 Apr 2007 @ 3:21 AM

  21. Re 18, The USA produces 25% of all global emissions and has a relatively small population (5%) and it is here that real climate and others are making their case because in the USA they are having trouble getting the whole idea through to their people and politicians. I believe that the way that the US political system is set up and works means that the greens nees money to lobby and seduce politicians just like the ultra rich fossil fuel lobby does. Alaska will be a waste land and the middle east a war zone before this argument is ended.

    Comment by pete best — 30 Apr 2007 @ 4:22 AM

  22. #5 – I’m sitting in the ‘Mitigation’ chapter closing negotiations now. Obviously I can’t say what’s going on, but I think it’s safe to say that the final report will offer some new insights on how we move from where we are today to where we need to be in a few decades time.

    It would be /extremely/ interesting to see some discussion on mitigation on RealClimate. I realise it’s not Climate Science per se, but it’s as hotly debated an area and as important.

    Comment by James Davey — 30 Apr 2007 @ 5:51 AM

  23. How would you change your private life to protect the environment?

    Comment by Tibor Kiss — 30 Apr 2007 @ 5:56 AM

  24. Re #21, I would hope that there is emphasis on how to get there rather than just the end product. For instance the UK has committed itself to a 60% reduction from 1990 levels by 2050 but as yet the document on how it is going to get there is missing, in other words they can make progress during the early years (obvious reductions) and get a 1/3 or CO2 removed but then it gets progressively harder to remove the other 2/3rds as that requires greater and greater strategic planning and it is this that becomes politically unsettling. The worlds population is increasing, the worlds most populous countries want what we have and have the means to get it now that the the west in preapred to invest and as yet there is no technology solutions currently available to either remove CO2 or not produce it at all that are mature and commercially available. We all know that we have to reduce demand and not increase supply so much.

    I reckon that it cannot be done and presently I side with James Lovelock. Some of the changes required need new energy infrastructures like a new decentralised grid, things have to be redesigned and that will cost trillions.

    Comment by pete best — 30 Apr 2007 @ 6:00 AM

  25. Typo!

    A lot of good reading ahead. I read chapter 6 on paleo climate. Too bad there is not more about the Miocene climate (would love to see an article on RC about this one day). I could not help myself to point out this typo: page 464 :’A likely cause for the 8.2 ka event is an outburst flood during which pro-glacial Lake Agassiz drained about 1,014 m3 of freshwater into Hudson Bay extremely rapidly (possibly 5 Sv over 0.5 year; Clarke et al., 2004).’
    Lake Agassiz was larger than the average fish pond??

    Comment by Bob Schmitz — 30 Apr 2007 @ 6:46 AM

  26. In the Summary for Policymakers on page 10:

    It is likely that there has been significant anthropogenic warming over the past 50 years averaged over each continent except Antarctica (see Figure SPM.4). The observed patterns of warming, including greater warming over land than over the ocean, and their changes over time, are only simulated by models that include anthropogenic forcing. The ability of coupled climate models to simulate the observed temperature evolution on each of six continents provides stronger evidence of human influence on climate than was available in the TAR.

    The figure shows computer model output with and without anthropogenic effects for all continents except Antarctica. Does this mean that the models can’t account for the data there, or that such data isn’t sufficient to make a judgment? It seems like the omission needs more explanation.

    Comment by David Eubanks — 30 Apr 2007 @ 8:05 AM

  27. nuclear is not a long term soultion (waste disposal, limited fuel, and high cost of dealing with aging nuclear power plants).

    The first is not a difficult problem (indefinite surface storage is acceptable), the second is very likely surmountable (for example, by extraction of uranium dissolved in seawater), and the third is demonstrably not a problem at all.

    What has held nuclear back is capital cost of the plants themselves, but the renewable alternatives face this problem in an even stronger form.

    Comment by Paul Dietz — 30 Apr 2007 @ 8:23 AM

  28. #24 – Mostly it is because there are very few observations of what the climate is doing on Antarctica, due to the fact that the continent is only inhabited by a small number of scientists (and penguins and possibly whalers in the past?). There simply isn’t the observational data to compare the models with.

    Remember that the Summary for Policymakers is just that: a summary. I expect there is a reference to the full chapter, where you would expect this to be discussed.

    Indeed, 3.2 is referenced and I can now find the sentence in that section of the full report: “..substantial gaps in data coverage remain, especially in the tropics and the SH, particularly Antarctica.”

    Comment by Timothy — 30 Apr 2007 @ 8:28 AM

  29. #23 – The implication of that question seems to be “how much pain are you willing to incur to leave a smaller GW footprint?” Correct me if I misinterpreted.

    My personal answer: it’s a question of cost. I stretch one high-tech income to cover me, my wife, our 5 children and our two cats. I buy energy efficient appliances and flourescent light bulbs, I insulate my doors and windows, and I keep electric devices which are not in use turned off. I still drive to work, mainly because biking in this hilly area would get me to work sweaty. I do not own a hybrid, because I cannot afford a new car at all and they are too new to be readily available in the used car market.

    If ‘renting’ solar (a la CitizenRe) becomes feasible, I will jump on that. If my utility offers me the option to ‘purchase’ energy from renewable sources, and is within 10% of my current costs, I will do it.

    I strongly believe that innovation will lead mankind away from spewing CO2 into the atmosphere. What will lead to better management of land use, and what will lead to less impact from livestock? These answers are less clear and will be more complex to manage.

    At a personal level, however, if we all make changes which, for example, average 10% better energy efficiency, we won’t notice much pain, we will lower our energy expenses, and the cumulative impact will be quite meaningful.

    Comment by Walt Bennett — 30 Apr 2007 @ 10:18 AM

  30. I wonder if RealClimate could help me with the key logic components that generate rising temperature forecasts. There’s a disparity between the temperature increases that Hansen and others predict, and the numbers I get from two of the core formulas that are said to be at the heart of this issue.

    One formula links radiative increases to rising greenhouse gases. For rising CO2, delta R = 5.35 * log(new PPM/original PPM). [This formula from NOAA’s AGGI webpage.] With new PPM = 382, original PPM = 280, this CO2 formula implies radiative forcing of 1.66 watts/meter^2.

    The second links temperature to rising radiative energy. Roughly, R = constant * T^4, where T is degrees Kelvin. I use 235 watts/meter^2 as the starting R, and 286 Kelvin as the starting T. Probably not exactly right, but pretty close I think.

    To go from PPM to rising temperature, I first calculate the radiative forcing. Then I add the radiative forcing value to the R in the second formula, and solve for T.

    When I do this, I don’t get a very fast increase in Temperature Kelvin. In fact, I’m surprised at how slowly the T value seems to rise as a function of rising PPM for CO2.

    Here’s what I do get:

    382 PPM –> +1.66 watts/meter^2 –> +0.50 Kelvin.
    450 PPM –> +2.54 watts/meter^2 –> +0.77 Kelvin.
    560 PPM –> +3.70 watts/meter^2 –> +1.12 Kelvin.
    740 PPM –> +5.20 watts/meter^2 –> +1.57 Kelvin.

    Each of these new Kelvin values are delta values from the starting number, 286 Kelvin (13 Celsius). Though 740 PPM vs 280 PPM represents a tripling of atmospheric CO2, the formulas cited imply an overall temperature increase of 1.57 Celsius, from 13 C to 14.57 C. Not an earthshaking result, I shouldn’t think.

    Are these formulas wrong? Am I using them improperly?

    I’d like to be able to make the case – for those of my friends who don’t believe GW is a priority – in as mathematical a way as possible. The math I’ve just cited, though, doesn’t seem especially compelling. Thanks for any help you can provide.

    [Response: Steven–those formulas provide the radiative forcing from co2 alone, i.e. they assume no feedbacks! It is the positive feedbacks, primarily water vapor feedback and ice-albedo feedback, that lead to significantly greater warming than would be predicted by the radiative forcing from co2 alone. Indeed, it is precisely the role of these positive feedbacks that is at the heart of discussions of climate sensitivity. A good primer is Gavin’s recent article Learning from a simple model. -mike]

    Comment by Steven H Johnson — 30 Apr 2007 @ 11:24 AM

  31. in the mid 1970s we where told that the earth is cooling down. know we are told its warming up who do we, or what do we belive..?

    The governments of the world have put money in research into “global warming” co2 levels etc, could it be something else but this. I must admit the evidence point towards higher co2 levels in future. But if that’s all you’re paying the scientist to find that what they will find. If your in a court of law what’s the evidence on the opposing side …?
    Could it be the earth is in a “natural cycle” could it be sun spots.
    All the computer models are based on human in put and not fact based on history. But what if the records don’t go far enough for the information that needs to be generated and is that accurate …. Questions questions questions

    Comment by Jamie — 30 Apr 2007 @ 11:41 AM

  32. Jamie, I’m gonna go way out on a limb and guess that maybe you aren’t a scientist. Am I right. First, climate scientists do not just look at CO2. They look at solar output. They look at water vapor. They look at cloud formation. They don’t look much at galactic cosmic rays because, frankly, nobody can come up with a coherent theory of how this mechanism might work.
    Your court of law in this case is the scientific community. Anybody who has relevant evidence is welcome to present it to that community and see if it holds up. So far, no alternative explanation has even come close to being able to explain what we’re seeing.
    As to the climate models, yes, they are the product of human beings, but they are constrained by the best data we have–both historical and current. Moreover they work very well. And the records–they go back 650000 years with fair accuracy, or if you want to include fossil evidence, even further. We KNOW humans are causing climate change. We KNOW it with as much certainty as we know that Einstein’s General Theory of Relativity is a good description of gravity. If you have “questions, questions, questions,” then go find “answers, answers, answers”, but go to a reasonable source of information or you won’t know anything more than you do right now. Misinformation does not fill the void of lack of information.

    Comment by Ray Ladbury — 30 Apr 2007 @ 12:09 PM

  33. Re: #31 (Jamie)

    in the mid 1970s we where told that the earth is cooling down.

    Told by whom?

    Comment by tamino — 30 Apr 2007 @ 12:12 PM

  34. RE#27, Paul – to repeat, it still seems to be that if you have $4 billion to spend on non-CO2 producing energy sources, the better investment would be to build 40 solar-cell manufacturing facilities at $100 million apiece; for example see Honda Solar Factory; this would result in some 1,100 megawatts of solar cell capacity being produced per year, in comparison to a single nuclear power plant (typical power level: 600-1200 MW) being built.

    While some may claim that nuclear power is far cheaper, if you look at the history of nuclear power cost overuns, you see that $4 billion for a single plant is an underestimate; for example the Shoreham Nuclear Power station came in at $6 billion. At the end of the lifetime of a nuclear plant, you have a huge, toxic mess to clean up; after 30 years of comparable solar cell manufacturing, you have 30 MW of installed solar power (assuming good PV panel lifetimes). Solar PV is a far better approach, with immediate payoffs.

    Comment by Ike Solem — 30 Apr 2007 @ 1:27 PM

  35. RE#31 – The IPCC report addresses that in chapter one, pg 98:

    Not all theories or early results are verified by later analysis. In the mid-1970s, several articles about possible global cooling appeared in the popular press, primarily motivated by analyses indicating that Northern Hemisphere (NH) temperatures had decreased during the previous three decades (e.g., Gwynne, 1975). In the peer-reviewed literature, a paper by Bryson and Dittberner (1976) reported that increases in carbon dioxide (CO2) should be associated with a decrease in global temperatures. When challenged by Woronko (1977), Bryson and Dittberner (1977) explained that the cooling projected by their model was due to aerosols (small particles in the atmosphere) produced by the same combustion that caused the increase in CO2. However, because aerosols remain in the atmosphere only a short time compared to CO2, the results were not applicable for long-term climate change projections. This example of a prediction of global cooling is a classic illustration of the self-correcting nature of Earth science.

    This just shows the lengths some people will go to – repeatedly citing a few papers from the 1970’s as evidence that no one understands climate… can you imagine a similar claim regarding, say, HIV and AIDs? “In the 1970s, scientists didn’t know about HIV and AIDs, so why should we believe them now?”

    Comment by Ike Solem — 30 Apr 2007 @ 1:35 PM

  36. Re #31

    Jamie,

    In the 1970s the earth was cooling down, now it is warming up. Is that so hard to believe?

    In the 1970s it was discovered that when the climate changes it usually does so abruptly, and so a rapid cooling was thought to be the main danger. Now, however, no one seems to have worked out that a rapid warming is the most likely catastrophe!

    Comment by Alastair McDonald — 30 Apr 2007 @ 1:46 PM

  37. In the 1970s the earth was cooling down …

    Let’s dispel this myth once and for all.

    Analyzing GISTEMP data for the 1970s gives a positive rate of global temperature change — warming! — of 0.05 deg.C/decade. But the error bars are +/- 0.19 deg.C/decade, so the trend is not statistically significant.

    In fact the much-vaunted “global cooling 1940 to 1970″ is not real either. Then trend for that time period is -0.25 +/- 0.3, again not statistically significant. The cooling is from about 1944 to 1951, the rest of that time shows no sign of any significant change.

    The only isolated decades which have statistically significant trends are (all in deg.C/decade):

    1930s: warming +1.8 +/- 1.2
    1940s: cooling -1.6 +/- 1.0
    2000s: warming +3.1 +/- 2.1

    The much higher error range for the 2000s is mainly due to the fact that we have less data (the 2000s aren’t over yet).

    Comment by tamino — 30 Apr 2007 @ 2:52 PM

  38. My favorite recent source on mitigation is ‘Heat’ by George Monbiot. While it is very UK centric and, I believe, wrong about a few issues, it is the only work I’ve seen that specifies changes to create an industrial society with vastly (90%) less carbon emissions. I’d like to know what folks here think.

    Comment by Ed G. — 30 Apr 2007 @ 2:58 PM

  39. Re: #37 (tamino)

    Correction to my previous post: all the numbers are deg.C/century, not deg.C/decade

    Comment by tamino — 30 Apr 2007 @ 2:59 PM

  40. Typo – re#34, that should be 30,000 MW installed after 30yrs, not 30!

    You can take a look at the temp record here, which supports tamino’s conclusions.

    It’s also now well understood that large volcanic eruptions have a short-term cooling effect, see GW FAQ: effect of volcanic activity (short-term being the key phrase, after Church et al Nature 2005, and also http://www.llnl.gov/str/JulAug02/Santer.html )

    Thus, a large volcanic explosion this year would result in cooling temperatures for a few years… but the long-term trend would soon override this. This illustrates the natural variability – who wants to bet that there will be a large volcanic explosion this year? Noone can assign a realistic probability to that one, but 1 in 10 is the recent historical average.

    Comment by Ike Solem — 30 Apr 2007 @ 4:40 PM

  41. re #30 and Mike’s response to my post. As you suggested Mike, I have re-read Gavin’s earlier post. I think it ends up about where I do. Gavin suggests a sensitivity of 0.3C/(W/m^2) with no feedback, and in an albedo feedback example shows that rising to 0.33C/(W/m^2). Those results are similar to my back of the envelop scratchings in Excel.

    In other words, it takes a forcing increase of approximately 3 W/(m^2) to produce an increase of 1 degree Celsius.

    The simple incremental CO2 forcing that comes from 380 PPM rising to 450 PPM – if NOAA’s formula is right – is only 0.27 W/(m^2). Before any feedbacks are added in. Not much of a Temperature gain in that, is there?

    Even the baseline forcing – 280 PPM to 450 PPM – implies a rise in temperature of only 0.77 degrees Celsius. Before feedbacks are taken into account. Still not much of an implied temperature gain, especially not if the sensitivity is 0.33C/(W/m^2).

    You’ve said you’d be summarizing the IPCC analyses, including, of course, the IPCC temperature forecasts. May I sugggest adding to your summary a table that lines up the variables?
    – CO2 PPM changes expected in coming decades
    – Other GHG changes expected over the same time period
    – Anticipated W/(m^2) from GHG forcings
    – Anticipated W/(m^2) from albedo forcings
    – Anticipated W/(m^2) from water vapor forcings
    – Temperature changes implied by these forcings

    The point is simple. If Temperature change is a function of a forcing change, and a forcing change is a function of a Greenhouse Gas change plus a feedback loop, then it would be cool to have a table that connects the dots. GHG changes + Feedback changes –> Total forcing changes –> Total temperature changes.

    I assume the IPCC estimates will include some forecasts that show temperatures rising by as much as 3 to 4 C. If Gavin is roughly right, that the temperature sensitivity is somewhere around 0.33C/(W/m^2), then it’ll be interesting to see where the forcings come from that yield those predicted temperature increases.

    One last thought. Blackbody temperature changes are interesting. But climate is ultimately about atmosphere, isn’t it? Is it at all likely that temperatures rise first in the atmosphere? That ocean and land temperatures lag the atmosphere? Is it possible for climate effects to outpace ocean & land warming rates?

    Thanks so much for your patience and the teaching you do with this website!

    [Response: I think you’ve misunderstood Mike’s point. My calculations for the simple model are not representative of the real world (as I think I stated multiple times). They are illustrative of the kind of calculations that go on, but they are not a replacement for the more complicated ones. The most likely sensitivity is around 0.75 C/(W/m2), not 0.33. See http://www.realclimate.org/index.php/archives/2006/03/climate-sensitivity-plus-a-change/ for observationally based reasons for that conclusion. – gavin]

    Comment by Steven H Johnson — 30 Apr 2007 @ 4:41 PM

  42. RE #34 IKE.

    Before we go off quoting the costs and troubles of a nuclear power plant built over 20 years ago we might have a look around at other more up to date stuff. I figure these guys might have learned something in 25 years. Kinda like GW scientists learned stuff.Just a hunch.

    Not a settled matter you know.. but I found this. again, it’s just one data point, but it’s not 25 years old.

    http://www.nei.org/index.asp?catnum=3&catid=186

    Now, the IRONIC thing I found was in your very next post, you are JUSTIFIABLY critical of somebody for reaching back to to the 70s for scientific papers. That was FUNNY as hell, but ironic. First( in #34) you reach back to the same period to pull up example to strengthen your case against Nukes and then you slam somebody for doing essentially the same thing. I thought you would find this as humerous as I did. Kind of like running with scissors .

    Finally, go check the honda numbers again. The plant looks like it is sited on existing corporate property ( so those costs are probably not included), capitalization is 4B Yen. Total investment is 7B Yen. Finally, I’m seeing PV lifespans guaranteed at 10-20 years. I’m not critical of solar, but I would take a bit more care in comparing alternatives.

    Anyways, I always enjoy your posts.

    Comment by steven mosher — 30 Apr 2007 @ 5:25 PM

  43. Seabrook NH is more recent than that (completed late 80s or early 90s I believe) and United Illuminating Customers in Connecticut are still paying it off.

    There has been almost no reactor construction since the 1970s in the US, so all the domestic datapoints are old.

    Comment by Roger Smith — 30 Apr 2007 @ 6:48 PM

  44. It appears (as usual) the IPCC reports are way out of date before they are published. A new paper “Arctic Sea Ice declines – faster than forecast” in Geophysical Research Letters by researchers at NCAR and the U of Colorado National Snow and Ice Data Center show that the Arctic may be ice free by 2020, 30 years ahead of the forecasts by the models. As I stated in an earlier post several months ago, Dr. David Barber (a sea-ice specialist at the University of Manitoba), predicted the Arctic could be ice free in 15 years (Feb 15, 2006). Looks like more people are agreeing with him. Looks like again the models come up real short. Another surprise (and I think more are coming).

    Wish I could remember which paper I read several months ago where the average age of the sea ice in the Arctic is now less than 3 years old (memory fading with age). So apparently the ice is turning over a lot faster than originally thought.

    Also, the models were way off on the melting of the Greenland ice sheet. I can be critical of models since I am a computer scientist (retired) who has done some modeling.

    As I learned in my marine science courses many years ago, the Arctic is our thermostat for the northern hemisphere. Once it is broken, we had better hang on for a wild ride.

    Comment by Jim Crabtree — 30 Apr 2007 @ 7:44 PM

  45. Re: faster than expected

    Official memorandum by directors of NOAA/NWS and NWS North Central River Forecast Center (NCRFC) states:

    ‘the mission of the NCRFC was operational in nature, and that Global Warming was beyond the time window of our hydrologic forecast mission.’

    (2000,2001).

    Comment by pat n — 30 Apr 2007 @ 8:06 PM

  46. Re #44: Here’s the link to the press release on the new Arctic sea ice paper. I don’t recall seeing your prior comment on the prediction from Barber, but IIRC Wieslaw Maslowski (the U.S. Navy’s sea ice expert) was saying something similar at least two years, and in a recent AMS presentation noted that simply eyeballing the trend led to the conclusion that the summer sea ice is not long for the world (my phrasing).

    Comment by Steve Bloom — 30 Apr 2007 @ 8:17 PM

  47. Re #44 “Arctic Sea Ice declines faster than expected”

    Those that can’t access GRL can check out this recent poster on the same topic by the authors (from the 2nd CIRES Symposium a few weeks ago).

    Comment by SCM — 30 Apr 2007 @ 8:22 PM

  48. Re #41 and Gavin’s reply. Thanks Gavin. I followed the link and read the observations. Also your reply to the first post following, in which you say the forcing for a doubling of CO2 is roughly 5.3 * LN(560/280), or 3.7 W/(m^2). This is the calculation I’ve already been guided by.

    I must be making an amateur’s mistake of some kind, though. On the assumption that a doubling of CO2 yields a forcing value of 3.7 W/(m^2), I add 3.7 to the value of G in your Stefan-Boltzmann formula, and I solve for Temperature. The increase in T is only a shade over 1 degree C, not the 2+ degrees that you say is the likely minimum.

    What am I doing wrong? Is it a mistake simply to increase the value of G by 3.7 W/(m^2), and then solve? Or am I wildly off in the value of sigma? (I’m using a sigma that I derived from your numbers, with G ~ 390 and T ~ 288.) Thanks again.

    Comment by Steven H Johnson — 30 Apr 2007 @ 8:27 PM

  49. While I was reading Ch 6 of the IPCC report on Paleoclimate I came across the description of the Paleocene Eocene Thermal Maximum 55Ma. They describe a very large step input of carbon into the atmosphere and the ocean. Both Atmospheric CO2 and Ocean Carbon content increased in magnitude similar to what we are seeing today. How do we know that we are not seeing a repeat of the PETM?

    Comment by Dave McFarland — 30 Apr 2007 @ 9:20 PM

  50. “Alaska will be a waste land and the middle east a war zone before this argument is ended. ”

    I don’t get your point, pete. Save for its oil, I thought Alaska is a wasteland (scenic to be sure…), and the Middle East is a war zone…

    Comment by Rod B. — 30 Apr 2007 @ 9:22 PM

  51. Re 31,

    http://www.denialism.com/2007/03/what-is-denialism.htm

    “We believe there are five simple guidelines for identifying denialist arguments. Most denialist arguments will incorporate more than one of the following tactics: Conspiracy, Selectivity, False Experts, Impossible Expectations/Moving Goalposts, and Argument from Metaphor/violations of informal logic.”

    You have an almost perfect score, congratulations!

    Comment by Fernando Magyar — 30 Apr 2007 @ 9:45 PM

  52. The included link in the my previous post seems to be broken it is found on this page:
    http://scienceblogs.com/denialism/2007/04/hello_to_scienceblogs.php

    Comment by Fernando Magyar — 30 Apr 2007 @ 9:51 PM

  53. #31 and #36 TROLL. re, “global cooling predicted in 1970s… now they predict global warming … so scientists should not be believed.”

    This is covered several times on this site and you know it.

    Alastair, these are senseless trolls.

    I present hard evidence below, including papers, that show your post is completely ignorant and blatent progaganda…now, where is your evidence?????

    There was no scientific consensus on cooling in the 1970s in the scientific journals (not including pop mags, like Time or National Geographic), however there is now a strong consensus that it is warming in the journals. This is the difference between night and day.

    This site covers has covered it pretty well as any honest person knows.

    “The point to remember, says Connolley, is that predictions of global cooling never approached the kind of widespread scientific consensus that supports the greenhouse effect today. And for good reason: the tools scientists have at their disposal nowâ??vastly more data, incomparably faster computers and infinitely more sophisticated mathematical modelsâ??render any forecasts from 1975 as inoperative as the predictions being made around the same time about the inevitable triumph of communism.” Newsweek

    “Least apologetic excuse for getting a climate story wrong:
    Newsweek explains its 1975 ‘The Cooling World’ story.”
    http://realclimate.org/index.php?s=cooling&submit=Search&qt=&q=&cx=009744842749537478185%3Ahwbuiarvsbo&client=google-coop-np&cof=GALT%3A808080%3BGL%3A1%3BDIV%3A34374A%3BVLC%3AAA8610%3BAH%3Aleft%3BBGC%3AFFFFFF%3BLBGC%3AFFFFFF%3BALC%3A66AA55%3BLC%3A66AA55%3BT%3

    http://www.realclimate.org/index.php/archives/2006/10/global-cooling-again/

    “I should clarify that I’m talking about predictions in the scientific press. There were some regrettable things published in the popular press (e.g. Newsweek; though National Geographic did better). But we’re only responsible for the scientific press. If you want to look at an analysis of various papers that mention the subject, then try
    http://www.wmconnolley.org.uk/sci/iceage/.”

    http://www.realclimate.org/index.php/archives/2005/01/the-global-cooling-myth/

    Comment by Richard Ordway — 30 Apr 2007 @ 10:11 PM

  54. RE #29, Walt, you may be interested in NATURAL CAPITALISM by Paul Hawkin and Amory Lovins, see http://www.natcap.org
    They figure we can reduce our GHG emissions by more than half cost-effectively, even by 75% or more. And I heard Hunter lovins say something like, “The poor cannot afford not to become energy efficient & conservative” & “The national energy policy comes down to the cracks around our windows.”

    There are also some other hidden savings in “doing the right thing” — the EC (environmentally correct) thing. For instance, offsetting some driving with walking & cycling, and eating lower on the food chain could improve health & lower medical bills.

    So re your questions “What will lead to better management of land use, and what will lead to less impact from livestock?” Eating less meat! Which is also good for the health. And when you consider that many toxins bioaccummulate up the food chain (toxins on plants get more concentrated in livestock, and still more concentrated in people who eat the livestock), well, there’s even more reason to reduce meat consumption. Going green is a win-win-win-win situation. Not doing so is a lose-lose-lose-lose situation.

    Then people ask, if it makes sense to do all these things anyway (without considering global warming), then why haven’t they done them already? The answer may be that economists are wrong about man being rational and maximizing. Maybe there’s something disturbing and perhaps Freudian going on deep in our psyches — some thanatos death wish. Or, we’re just crazy.

    Comment by Lynn Vincentnathan — 30 Apr 2007 @ 10:19 PM

  55. Re: gavin’s response to 41> “The most likely sensitivity is around 0.75 C/(W/m2), not 0.33. See http://www.realclimate.org/index.php/archives/2006/03/climate-sensitivity-plus-a-change/ for observationally based reasons for that conclusion.”

    Most of the observations seem to be based on changes in insolation (such as volcanic dimming). How do we know that sensitivity in C/(W/m2) is the same for GHG forcing as for insolation forcing?

    The two sources of forcing have different ‘fingerprints’ and cause different distributions (vertically and geographicly) of temperature change. How do we know that those distributions do not cause different feedback effects?

    [Response: They do – slightly. Read this paper for a full discussion of the issue. The bottom line is that the concept works pretty well for almost all forcings (otherwise we wouldn’t use it). You can use the simple model discussed before to show why it works in the simplest case. – gavin]

    Comment by Steve Reynolds — 30 Apr 2007 @ 10:26 PM

  56. Re # 15 Eli,
    I don’t understand your comment. I was responding to Vern’s (#4) request that Gavin to savage any conclusion in the IPCC report that is not based on incontrovertible evidence. How do you interpret that request?
    Bet on what? I’m quite familiar with the major evidence for AGW, and I’ve learned from this site the serious flaws in Gray’s and Lindzen’s arguments.
    Perhaps you misread my comment, or Vern’s?

    Comment by Chuck Booth — 30 Apr 2007 @ 10:41 PM

  57. This is a bit off topic, but does anyone have recommendations for a good, general book (for the “educated layman”) covering the science of global warming? I read and enjoyed “Field Notes From a Catastrophe” but it left me wanting more.

    Thanks!

    Comment by cce — 1 May 2007 @ 12:26 AM

  58. Intresting discussion regarding global cooling in the 60’s, 70’s. It gets quite emotional. Key reasons it didn’t become a scientific concensus are (i) that the trend didn’t last long enough for the hysgteria to set in and (ii) that an international body to study the issue was not established. The concern for global warming started in a similar way. People watched the trend for a few years and started to make a few noises about it, some media stories. One or two well-known scientists made some strong statements. The IPCC was formed and the snowball started to role. It will role until the its realised we are no longer in a rising trend. What I am sure about is that when we move again into a cooling trend, no AGW advocates of today will admit any error. What will be blamed is aerosols and that this other form of man-made pollution is taking over – and so it will still be our fault. You heard it here first.

    [Response: Sadly no, I didn’t hear it first here, its been said many times before. For GC, you can look at http://en.wikipedia.org/wiki/Global_cooling . The key reason it didn’t become a sci cons was that the science didn’t support it – William]

    Comment by PHE — 1 May 2007 @ 1:22 AM

  59. #36 Alastair, I was around in the 70’s, and I must say that it didn’t feel like a cooling then, but now all over the world there is a warming felt by billions. The difference: it was a media prediction (perhaps inspired by Milankovitch theory) compared to the media reacting with no shortage of people in awe of deadly heat waves “la canicule 2003″ , not having any winter in Europe amongst other myriad warming stories, many not heard from every place on Earth. The IPCC meets from common knowledge created by temperature change.

    Comment by wayne davidson — 1 May 2007 @ 2:18 AM

  60. As a non-scientist I look forward to your step by step progression through IPCC report. I also appreciate the comment entries.
    Several years ago,
    I bought a copy of Natural Capitalism by Hawkins and Lovins. GREAT BOOK!

    Comment by Edo River — 1 May 2007 @ 2:23 AM

  61. #57: “This is a bit off topic, but does anyone have recommendations for a good, general book (for the “educated layman”)”

    Try Global Warming : The Complete Briefing by John Houghton. It is intended for a nontechnical audience and is detailed and thorough. You can check out the table of contents and some sample pages via the above amazon link.

    Comment by SCM — 1 May 2007 @ 4:59 AM

  62. CLIMATE SENSIVITITY ISSUE

    The issue of how sensitive climate is appears to be the real issue in regards to how far humankind should go in mtigating carbon release into the atmosphere. Lubos Motl (who is probably well known to real climate and tends to have an opinion on anything that is controversial in science) writes this blog http://motls.blogspot.com/2006/05/climate-sensitivity-and-editorial.html on the subject and quotes well known climate detractors like Lindzen at MIT.

    He agrees that there cannot be a runaway effect but he then takes the posiiton that the current 1.5 to 4.5 IPCC projections of temperature are incorrect citing the fact that 560 ppmv would mean no more than 1.5 C of warming through CO2 alone. So what is the issue here, I know from realclimate that he must be incorrect but I am no mathematician and hence I cannot vouch for his equation or his conclusions he draws from it (although I do know that the formual is exponential in nature and that we get more warming from the early CO2 increase than we do for even more) so he could be right for all I really know.

    So what can I say that might reveal his depection: Is he only using CO2 and not greenhouse gases? Has he taken into account the albedo and aerosols to ?

    Can realclimate answer this one for me please. Is he being economical with the truth or disengenuous to science and hence scientists?

    Comment by pete best — 1 May 2007 @ 5:03 AM

  63. #57 #60
    After that one try “The Last Generation” by Fred Pearce. It mercifully breaks GW up into small chapters and gives Stephen King a run for his money.

    http://www.amazon.co.uk/Last-Generation-Nature-Revenge-Climate/dp/1903919878

    Keep up the good work chaps and Tamino – ta for the cooling info.

    Comment by Mike Donald — 1 May 2007 @ 5:35 AM

  64. I was disappointed that Eric shut down the discussion on the carbon cycle just as I was about to post. My question relates to just how well we understand the carbon cycle actually. I have reviewed the Wikipedia entry on this topic (I know, I should read the literature) and remain unsatisfied. For example, the Wikipedia entry fails, so far as I can see, to consider the impact of rising atmospheric CO2 levels on the biomass. We know that rising CO2 levels will stimulate plant growth. In effect, that sequesters CO2 in vegetative matter, and in a fashion that increases the biomass as atmospheric CO2 levels increase.

    There may well be other aspects of the cycle that are poorly understood. For example, I seriously doubt that we really understand the CO2 issues with the ocean.

    So my question in regard to the CO2 cycle is – just what level of confidence do we put on our understanding of the CO2 cycle. IPCC, Algore, RC and Hockey Team all suggest that we have a very clear understanding of this (Very Likely probably), but I seriously don’t see how this conclusion can be substantiated.

    Comment by trevor — 1 May 2007 @ 5:39 AM

  65. I have a question about arctic sea ice that I’ve yet to see addressed, and it won’t get out of my brain and just leave me alone —

    While it’s true that sea ice lowers the albedo of the arctic region, we’re talking about a region that is a net heat loser on an annual basis. I’m not caffinated well enough this morning to calculate the annual watt-hours per square meter received at the north pole, but I’m guessing it isn’t a big number.

    How does heat loss in the north polar region change with and without sea ice cover?

    Comment by FurryCatHerder — 1 May 2007 @ 6:45 AM

  66. Re #48, having struggled through the simple model article recently, maybe I can clarify. If you double CO2 today, then forcing is 3.7W/m^2. However, as the atmosphere warms, other things change. For example, warmer air holds more water vapour which adds more forcing.

    Both observations (of a more than 0.6C rise with only 380ppm CO2 level), and models show that the net effect of feedbacks is positive.

    Hope I’ve got that about right.

    One thing that really confused me till I got my head around it was the way papers talk about forcing (W/m^2/K) and then slip smoothly into sensitivity C/(W/m2) once they start talking about feedbacks.

    Comment by Steve Milesworthy — 1 May 2007 @ 6:54 AM

  67. Jamie and Alastair and PHE, your eagerness to abandon the conservation of energy tells me you don’t have much scientific background. The energy of a system–such as climate–does not change without something changing it. In the 1970s, yes, there were some observations of cooling, and even at the time, many researchers understood the cause to be blocking of sunlight by aerosols from the burning of fossil fuels. By the late 1990s the climate models had evolved sufficiently that this could be demonstrated. So, not only did scientists understand the cause of warming from the start of the industrial revolution into the early 1900s, they also understood the cause of the cooling observed from ~1940 to ~1975, and when emissions were controled, the warming re-emerged. Rather than undermining the credibility of climate science, this confirms it.
    Your assertion that climate can change as a result of a “natural cycle” is as unscientific as the claim of a creationist that “GODDIDIT” unless you have some hypothesis as to what the forcing function of that “natural cycle” may be. Science works. Learn some of it.

    Comment by ray ladbury — 1 May 2007 @ 7:13 AM

  68. … the cooling observed from ~1940 to ~1975 …

    I’ll keep saying it: there is not cooling from ~1940 to ~1975.

    Trend analysis of GISTEMP data from 1940 to 1975 indicates a temperature change rate of -0.15 +/- 0.25 deg.C/century. Note the error range is larger than the value, so the indicated trend is not statistically signficant.

    The only real “global cooling” is from 1944 to 1951. Seven years. That’s all, folks. For the remaining period in question, from 1951 to 1975, the indicated trend is +0.07 +/- 0.5 deg.C/century. This indicates warming, not cooling, although again the trend is not statistically significant.

    Comment by tamino — 1 May 2007 @ 8:02 AM

  69. Just a quick question. Why wasn’t this released in February along with the summary? I know of no other field where a summary document is released months before the paper that it is supposed to summarize.

    Comment by cbone — 1 May 2007 @ 8:21 AM

  70. The “global cooling” talked about in a couple of glossy magazines (And Rob Reiner. We can’t forget his pivotal role.) was about the fact that we were in an interglacial period which could end. Which is true: interglacial periods do end. Since we had fairly bitter winters from 76-77 through 78-79, there was the spice of memory added to the mix.

    There wasn’t any discussion in the scientific literature about it.

    Comment by Jeffrey Davis — 1 May 2007 @ 8:24 AM

  71. Trevor, CO2 stimulates plant growth only to the extent that there are no other limiting factors. I believe Hank posted on this several posts back. The short answer is that it’s mixed. Some plants do better and some do worse. As I recall, weeds thrive. So, yes, this has been looked at.
    The other misunderstanding reflected by your post is that unless the plant growth involved is dominated by long-lived woody plants, there isn’t much increase in long-term sequestration of carbon. Indeed, as the plants die and decay, a lot of the carbon goes back into the system as CH4, and so actually increases greenhouse efficiency. This straw has been grasped at repeatedly, and hasn’t supplied much bouyancy so far.

    Comment by ray ladbury — 1 May 2007 @ 8:25 AM

  72. Trevor, you’re right, you should read in the current science.

    Beware assumptions; “we’re sure more CO2 is good, it fertilizes life, and we’re sure the uncertainty is great, and we’re sure that there’s no need to worry” is the PR from the denial sources.

    Try your own words as a search term:
    http://scholar.google.com/scholar?hl=en&lr=&scoring=r&q=rising+atmospheric+CO2+levels+on+the+biomass.+We+know+that+rising+CO2+levels+will+stimulate+plant+growth.&as_ylo=2006&btnG=Search

    You’ll need to visit a library, talk to the reference desk, and borrow most of the journals; the abstracts will get you started.

    Example:
    “Conclusions drawn from experimental works differ when the data are grouped in a way such that the relative frequency of test conditions does not determine the emerging trends, for instance unrealistically strong CO2-‘fertilization’ effects, which are in conflict with some basic ecological principles. I suggest separating three test conditions: uncoupled systems (plants not depending in a natural nutrient cycle) (I); expanding systems, in which plants are given ample space and time to explore otherwise limited resources (II); and fully coupled systems in which the natural nutrient cycling governs growth at steady-state leaf area index (LAI) and fine root renewal (III). Data for 10 type III experiments yield rather moderate effects of elevated CO2 on plant biomass production, if any. In steady-state grassland, the effects are water-related; in closed tree stands, initial effects decline rapidly with time. Plant-soil coupling (soil conditions) deserves far greater attention than plant-atmosphere coupling (CO2 enrichment technology).”

    New Phytologist (2006) 172: 393-411

    Comment by Hank Roberts — 1 May 2007 @ 8:26 AM

  73. A modest suggestion. Hank Roberts (whom I’ve learned a great deal from) often asks posters where they are getting their information about climate–especially when that information appears suspect. It occurs to me that it might be helpful in general if posters shared their sources of information–particularly the reliable ones, along with any biases they have observed. Realclimate remains my main source of scientific information about climate change. It is a goldmine. However, I also follow releases from NASA, NOAA and other sources. I do try to look at the IPCC reports, but I’m afraid that the politics here have a tendency to try to dilute the science (though in quite the opposite direction that the denialists imply). I try to flip through the stack of Science and Nature that accumulate over time. Unfortunately, I rarely make it to the library to read GRL anymore. Popular sources I use are Yahoo news. And I find the comments on the blogs at Scientific American an excellent source on the most popular denialist arguments of the day. I also try to keep in touch with colleagues at Physics Today, who actually still get to read this stuff as part of their day jobs. Nothing too novel or helpful, I’m afraid. But it’s a start.

    Comment by ray ladbury — 1 May 2007 @ 8:36 AM

  74. I have a question about the much cited in the MSM phrase – “Longer growing seasons”

    To me this sounds like the “Healthy Forests Initiative” or “No Child Left Behind” – who comes up with these phrases?

    It is really too bad that the 2 messages most widely received from the IPPC II is the (mmmm, sounds good) “longer growing season”, and that AGW will “only happen to poor people far away from us.”

    You scientists really need a Jeffrey Feldman type to control the message better. You can rely on the MSM to distort this.

    Comment by Susan K (not a scientist) — 1 May 2007 @ 9:34 AM

  75. Re: 43 “Seabrook NH is more recent than that (completed late 80s or early 90s I believe) and United Illuminating Customers in Connecticut are still paying it off.”

    Even more current, look at the truly huge overrun costs for Ontario Hydro’s Darlington plant on Lake Onatrio. For overruns on overhaul costs check for Ont Hydro’s Pickering plant, also on L. Ontario. The Bruce plant (on L. Huron) is currently being overhauled, but by a private firm, so figures will not likely be available.

    Comment by Jim Eager — 1 May 2007 @ 9:41 AM

  76. Just because a climate sceptics and trolls say that there was cooling from the 40s to the 70s does not mean that is not true. You only have to look at http://www.cru.uea.ac.uk/cru/info/warming/ to see that. Moreover, there were worries by reputable scientists that a rapid cooling could happen, See G.J. Kukla & R.K. Matthews, Science, 178, 190-1, 1972. Moreover, they were worried enough for it to reach the press, and for a letter to be penned to the President of the USA.

    Of course the worries now are far greater than those then, but it is wrong to deny that they existed. One might accuse those deniers of being dishonest, but it is clear to me now that it is their firm belief in the infallibility of scientists that is leading them astray, and that they find it difficult to accept that scientists could ever have been wrong.

    The problem is that they also believe that they too are infallible. When they are told the Arctic ice may be gone within 10 years, and as Jim Crabtree says “… the Arctic is our thermostat for the northern hemisphere. Once it is broken, we had better hang on for a wild ride” they are not afraid. For them, the IPCC consensus says that the ice will last until 2070 so that must be true.

    If even the scientist cannot face up to the facts, then what hope is there for the rest of us?

    Comment by Alastair McDonald — 1 May 2007 @ 10:29 AM

  77. Earth’s Climate Is Seesawing, According To Climate Researchers

    During the last 10,000 years climate has been seesawing between the North and South Atlantic Oceans. As revealed by findings presented by Quaternary scientists at Lund University, Sweden, cold periods in the north have corresponded to warmth in the south and vice verse. These results imply that Europe may face a slightly cooler future than predicted by IPCC, the Intergovernmental Panel on Climate Change.
    http://www.sciencedaily.com/releases/2007/04/070428170229.htm

    Comment by lars — 1 May 2007 @ 10:54 AM

  78. Jim Crabtree (#44) wrote:

    Wish I could remember which paper I read several months ago where the average age of the sea ice in the Arctic is now less than 3 years old (memory fading with age). So apparently the ice is turning over a lot faster than originally thought.

    State of the Arctic (NOAA)
    October 2006
    http://www.arctic.noaa.gov/soa2006/
    http://www.pmel.noaa.gov/pubs/PDF/rich2952/rich2952.pdf

    pg 16 Difference in Ice Extent (1979-2005)
    pg 18 Change in the age of ice on the Arctic Ocean (September 1988, 1990, 2001, 2005)
    pg 26 Changes in Permafrost temperatures at a depth of 20 m (Alaska Permafrost Observatory, 1977-2003)

    I believe pg 18 most closely corresponds to what you are thinking of.

    For something a little earlier:

    A rapidly declining perennial sea ice cover in the Arctic
    Josefino C. Comiso (NASA, 2002)
    http://neptune.gsfc.nasa.gov/publications/pdf/pubs2002/2_rapidly_decling_perennial.pdf

    Also, the models were way off on the melting of the Greenland ice sheet. I can be critical of models since I am a computer scientist (retired) who has done some modeling.

    I worked with highway traffic modeling a while back myself.

    Now this isn’t modeling, but as far as glaciers go, you might also be interested in:

    State of the Cryosphere
    National Snow and Ice Data Center
    http://nsidc.org/sotc

    In particular:

    SOTC: Glaciers
    http://nsidc.org/sotc/glacier_balance.html

    “SOTC: Glaciers” includes Chart of Global Glacier Mass Balance from 1961-2003

    State of the Cryosphere is meant for the general public. It uses Google Maps, images, etc. It might be worth getting the word out about.

    Comment by Timothy Chase — 1 May 2007 @ 11:05 AM

  79. Ike Solem (#35) wrote:

    Bryson and Dittberner (1977) explained that the cooling projected by their model was due to aerosols (small particles in the atmosphere) produced by the same combustion that caused the increase in CO2. However, because aerosols remain in the atmosphere only a short time compared to CO2, the results were not applicable for long-term climate change projections. This example of a prediction of global cooling is a classic illustration of the self-correcting nature of Earth science.

    Aerosols have in fact masked the effects of global warming through “global dimming” during the latter part of the twentieth century. However, some of their effects (e.g., sulfates lowering the albedo of clouds) contribute to global warming. There have been a number of posts on the subject of “global dimming” here in the past. One of Real Climate’s guest posters (Beate Liepert) was involved in some of the earlier modeling of its affects, including how it affects the formation of clouds, how sulfates decrease the albedo of clouds, how such polution can reduce the solar energy we receive on cloudless days, and how aerosols resulted in observed reduction of sunlight from the 1961-1990.

    Here are a few of the posts Real Climate has had on this:

    18 Jan 2005
    Global Dimming?
    Gavin Schmidt
    climate modeller at the NASA Goddard Institute for Space Studies in New York
    http://www.realclimate.org/index.php?p=105

    19 Jan 2005
    Global Dimming II
    Guest posting from Beate Liepert (Lamont-Doherty Earth Observatory)
    http://www.realclimate.org/index.php?p=110

    Anyway, for those who are interested:

    17 Apr 2006
    Global Dimming and climate models
    Guest posting from Beate Liepert (Lamont-Doherty Earth Observatory)
    http://www.realclimate.org/index.php/archives/2006/04/global-dimming-and-climate-models/

    Comment by Timothy Chase — 1 May 2007 @ 11:29 AM

  80. Just because a climate sceptics and trolls say that there was cooling from the 40s to the 70s does not mean that is not true.

    I agree that the fact that denialists claim it, doesn’t make it false. But it is still false.

    You only have to look at http://www.cru.uea.ac.uk/cru/info/warming/ to see that.

    Indeed. Look very closely at that graph. Look at the period 1951 to 1970. Does that look like cooling to you?

    Rather than trust what it “looks like,” I ran the numbers. I’m a professional mathematician specializing in the statistical analysis of time series. The numbers say: no cooling 1951 to 1970, or 1951 to 1975, or 1940 to 1970, or 1940 to 1975. The only verifiable global cooling is from 1944 to 1951. Seven years. That’s all, folks.

    Let’s all face the truth: global cooling from the 40s to the 70s is a myth.

    Comment by tamino — 1 May 2007 @ 11:42 AM

  81. Here is one angle I am interested in: the more temperate regions are experiencing warmer winters and fewer freezing nights which kill mosquitos. Consequently, mosquitos are having extended seasons, and mosquito-borne illnesses are moving to more temperate zones and are at risk of becoming endemic.

    A hemorrhagic type of dengue fever in Mexico:

    Lethal type of dengue fever hits Mexico
    By Mark Stevenson
    Sunday, April 1, 2007 – Page updated at 02:04 AM
    http://seattletimes.nwsource.com/html/nationworld/2003645837_dengue31.html

    Hemorrhagic dengue is also in the process of becoming endogenous to Taiwan due to warmer winters.

    Second dengue fever patient dies in Taiwan
    (November 1, 2006)
    http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-20061101-13131500-bc-taiwan-dengue.xml

    More dengue fever cases reported in India
    (October 17, 2006)
    http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-20061017-10114900-bc-india-dengue.xml

    Dengue Surveillance in Florida, 1997â??98
    Julia Gill,* Lillian M. Stark,* and Gary G. Clark
    Emerging Infectious Diseases, Vol. 6, No. 1, Januaryâ??February 2000, pp 30-35
    http://www.cdc.gov/ncidod/eid/vol6no1/pdf/v6n1.pdf

    Comment by Timothy Chase — 1 May 2007 @ 11:56 AM

  82. Incidently, there was a story a while back regarding the production of methane by plants. Real Climate had a couple of posts on it, first because it was puzzling, then because it got misrepresented in the press.

    11 Jan 2006
    Scientists baffled!
    http://www.realclimate.org/index.php/archives/2006/01/scientists-baffled/

    Every so often a scientific paper comes out that truly surprises. The results of Keppler et al in Nature this week is clearly one of those. They showed that a heretofore unrecognised process causes living plant material to emit methane (CH4, the second most important trace greenhouse gas), in quantities that appear to be very significant globally.

    Turns out that we have learned a little more in this regard:

    Fast-forward eighteen months. A group of Dutch researchers put the Max Planck team’s conclusions to the test by tracing radioactive carbon isotopes through plants. Their conclusion: “There is no evidence for substantial aerobic methane emission by terrestrial plants.”

    The Missing News of the Missing Methane
    Category: Global Warming
    by Carl Zimmer
    http://scienceblogs.com/loom/2007/04/27/the_missing_news_of_the_missin.php
    Posted on: April 27, 2007 4:24 PM, by Carl Zimmer

    Comment by Timothy Chase — 1 May 2007 @ 12:18 PM

  83. Hello, is there any evidence that co2 in the paleo record causes catastrophic warming. Is there any evidence that co2 amplifies?

    Thanks

    Comment by Dana — 1 May 2007 @ 12:27 PM

  84. Tamino wrote “The only verifiable global cooling is from 1944 to 1951.”

    I apologize for adding scifi to the talk, but I was asked to ask you good people whether you think the Hiroshima/Nagasaki/above ground A-bomb tests might have generated enough airborne debris to contribute significantly to the cooling effect Tamino cited (and I suppose whether general wartime activity elevated fossil fuel use enough to accelerate post-war AGW some). This question I gather comes from musing about Dr. Sagan’s nuke winter idea. I also have been asked to say that the meaningful contributors to RC are simply brilliant :)

    Comment by ghost — 1 May 2007 @ 12:54 PM

  85. Re #65: Probably the key relationship to bear in mind regarding Arctic sea ice is that the heat absorption will be through the open water in the summer, but that winter sea ice will still develop and greatly reduce the amount of heat lost then. While summer insolation is obviously much less than farther south, it’s still large enough to do the job (although not by itself at present, since encroaching warm currents have been found to be a big part of it). Another aspect (IIRC) is that the persistence of the Arctic sea ice is related to the presence of a surface layer of relatively fresh water that will be progressively disrupted (by mixing) as the warming proceeds, so the summer ice-free state will itself acquire persistence as that layer dissipates. NSIDC has good non-technical explanations of all of this.

    Comment by Steve Bloom — 1 May 2007 @ 12:58 PM

  86. Ray Ladbury – In #67, you state that scientists now understand the effect of aerosols on global mean temperatures in the 20th century and that the current models confirm the credibility of climate science regarding this issue. The IPCC AR4 report does not appear to share your confidence, as shown in Table 2.11. For the four types of aerosols, the report indicates a level of scientific understanding ranging from low, to low to medium; along with a low grade of consensus.

    In #71 you discuss stimulated plant growth and the lack of long-term sequestation of carbon that results from the increased growth. There is actually quite a bit of information to the contrary. The article below is a good place to start.

    http://www.co2science.org/scripts/CO2scienceB2C/articles/V10/N18/EDIT.jsp

    Thanks
    B Buckner

    Comment by B Buckner — 1 May 2007 @ 12:59 PM

  87. I would like to commend to everyone’s attention this article by British journalist George Monbiot, author of the book Heat: How to Stop the Planet from Burning:

    The Rich World’s Policy on Greenhouse Gas Now Seems Clear: Millions Will Die
    by George Monbiot
    May 1, 2007
    The Guardian/UK

    It is a pretty sobering assessment of the efforts of developed countries to reduce GHG emissions. Monbiot argues that even the most aggressive GHG reduction targets currently being proposed (e.g. by the EU, Britain and Sweden) fall short of what current science says will be needed to prevent “dangerous” global warming of 2 degrees Centigrade above pre-industrial levels.

    Comment by SecularAnimist — 1 May 2007 @ 1:28 PM

  88. M. Buckner —
    You’ve been misled by a PR “advocacy” site. Don’t take what you find there as accurate. You _always_ should look at the original paper, not rely on other people’s statements.

    You can check your sources with sourcewatch, to find out if they’re PR sites or not:
    http://www.google.com/search?q=co2science+sourcewatch

    Look them up:
    http://www.sourcewatch.org/index.php?title=Center_for_the_Study_of_Carbon_Dioxide_and_Global_Change

    In any area where you have some expertise, look for references you know something about and evaluate what they tell you against what you know, for example:
    http://scienceblogs.com/deltoid/2006/11/chinese_navy_disproves_global.php#comment-257716

    Comment by Hank Roberts — 1 May 2007 @ 1:39 PM

  89. B. Buckner, I couldn’t get your link to work, but I did spend some time poking around co2science. I recommend it to anybody who needs a good laugh. Must be nice having a job where all you have to do all day is cherrypick the latest studies that provide even minimal support to your position. Oh, and did I say support–Ex-Mob is providing a lot of it to co2science.org.
    So, you think all we have to do is plant trees? Then I suppose you’re fine with Al Gore’s carbon offsets, right?
    Yes CO2 does promote growth in some plants under some conditions. However, really long-term sequestration requires a continual increase in the amount of carbon stored in plants. Redwoods are a good carbon sink. Brussel sprouts (as anybody who has eaten them knows) are not. Short-lived plants die and decay, returning their carbon to the cycle fairly quickly, not just as CO2, but also a CH4–a more potent greenhouse gas. And long-lived trees grow slowly, and when they reach maturity, the growth stops. What is more, they stop growth under the canopy. So, while forests can act as carbon sinks, the potential is limited. And the assertion that CO2 is a benefit to agriculture is without merit–weeds like CO2 even more than crops do.

    As to aerosols, yes, they remain an area of uncertainty. They are certain enough that we know that if you dump soot into the air, you get cooling (or at least a slowdown in warming). They are also certain enough to nail the effect of a volcanic eruption such as Mt. Pinatubo nuts on. In other words, they are certain enough that we know they won’t change the answer dramatically.

    Comment by Ray Ladbury — 1 May 2007 @ 1:47 PM

  90. Recent studies looked at increased CO2 and other climate effects on plant growth. Remember, plants need more than CO2 and warmth to grow. Nitrogen and other nutrients in the soil, water levels, and light levels all play important roles. Merely increasing one or two of these factors may not give the expected results. For instance, increasing CO2 may not encourage the plants you would like to grow, but instead encourage “weeds.”

    Perspective with links to relevant articles:
    http://www.sciencemag.org/cgi/content/full/315/5812/606

    Also remember the rate at which this change is happening is faster than a natural climate shift rate, and desirable plants may not be able to move quickly enough. Also, the areas into which plants might migrate may not be suitable for their growth.

    Comment by Terry Miesle — 1 May 2007 @ 1:54 PM

  91. Re: #84 (ghost)

    … whether you think the Hiroshima/Nagasaki/above ground A-bomb tests might have generated enough airborne debris to contribute significantly to the cooling effect Tamino cited (and I suppose whether general wartime activity elevated fossil fuel use enough to accelerate post-war AGW some).

    I thought of that idea a little over a year ago; it does seem quite a coincidence that 1945 marked the first A-bomb explosions and several were tested throughout the remainder of the 40s. So I investigated the number of above-ground nuclear explosions, and found that they continued throughout the 50s, but the nuclear test ban treaty reduced the number greatly in the 60s. If I recall correctly, the last above-ground test was in 1970. Global cooling doesn’t match this pattern.

    Another idea is that the massive firestorms from conventional bombing late in world war II may have contributed to the global cooling 1944-1951. Moderators — any comments?

    Comment by tamino — 1 May 2007 @ 1:55 PM

  92. Regarding plant growth…

    The Chinese have been doing studies where they vent rice in the field with CO2 which simulates projected levels from 2050. Rice grows more quickly, but has considerably diminished nutritional value. Additionally, the does not take into account the increased temperature (rice is especially sensative to heat) or the effects of drought.

    Please see:

    Rising carbon dioxide could make crops less nutritious
    Jia Hepeng
    4 March 2005
    http://www.scidev.net/News/index.cfm?fuseaction=readNews&itemid=1969&language=1

    Comment by Timothy Chase — 1 May 2007 @ 2:04 PM

  93. Hank Roberts (#88) wrote:

    M. Buckner —
    You’ve been misled by a PR “advocacy” site. Don’t take what you find there as accurate. You _always_ should look at the original paper, not rely on other people’s statements.

    You can check…

    CO2Science is the name of the online newsletter. The organization is:

    Center for the Study of Carbon Dioxide and Global Change
    http://www.sourcewatch.org/index.php?title=Center_for_the_Study_of_Carbon_Dioxide_and_Global_Change

    Family-owned and strong ties to the fuel industry. Some background in agriculture, too, which might help to explain the cherry-picking.

    Comment by Timothy Chase — 1 May 2007 @ 2:30 PM

  94. Re #90 (TM): This new paper in PNAS discusses the role of nitrogen availability as the limiting factor in forest growth.

    Comment by Steve Bloom — 1 May 2007 @ 3:31 PM

  95. About mitigation, I posted a set of recommendations at:
    http://www.realclimate.org/index.php/archives/2007/03/the-ipcc-sea-level-numbers/#more-427, comment #308.

    These are radical, holistic re-visions of how we feel and behave toward Earth and how we relate to one another. They may seem too radical, in the sense of going to the roots of the problem, but the alternative is the Lovelockian Earth ridding itself of human pathogens, which is elegant as theory but mind-numbingly brutal in practice. At least let’s try to talk about some fundamental reformations in human society and relationships.

    Comment by stormboy — 1 May 2007 @ 4:14 PM

  96. #66 Mr. Buckner wrote: [There is actually quite a bit of information to the contrary. The article below is a good place to start.]

    [http://www.co2science.org/scripts/CO2scienceB2C/articles/V10/N18/EDIT.jsp]

    You have indeed been duped by the fossil fuel industry.

    They have taken a legititmate scientific paper and selectively edited it so that you will think and act the way they want you to.

    This is an old trick of theirs (and the left’s and the right’s as well on global warming) and it has helped stop any action on global warming/climate change for ten years….time that we might or might not have.

    Read the original paper at your library or from the origional source and not what someone wants you to believe.

    The Union of Concerned Scientists has this to say about the co2science.org website.

    http://www.ucsusa.org/ssi/archive/climate-misinformation.html

    and

    http://www.ucsusa.org/global_warming/science/skeptic-organizations.html

    Comment by richard ordway — 1 May 2007 @ 4:28 PM

  97. Timothy Chase (#78):

    Thanks for the additional info. Still not the paper I was looking for. I will do some more searching in the next few days.

    #92.

    The drop in nutrition value is true for wheat and other grains when CO2 passes a certain point. I would have to find a reference, but one of the Universities found that the caterpillars would not go into pupae stage.

    Comment by Jim Crabtree — 1 May 2007 @ 7:14 PM

  98. stormboy (#95) wrote:

    About mitigation, I posted a set of recommendations at:
    http://www.realclimate.org/index.php/archives/2007/03/the-ipcc-sea-level-numbers/#more-427, comment #308.

    These are radical, holistic re-visions of how we feel and behave toward Earth and how we relate to one another…

    Preamble: Our one and only planet is heating up, fast…
    4) De-throne the corporate rulers.

    OK there…

    Maybe before we get around to discussing your manifesto, we could cover the IPCC AR4 Report.

    I was thinking, we all have topics that we might want to touch on, whether it happens to be how well the plants might do with increased carbon dioxide, the projected intensities of storms, the spread of diseases, global dimming, etc. But rather than trying to discuss all of these things all at once, maybe we could discuss them as they come up which covering the report.

    In addition, rather than asking Gavin and the rest of the good people at Real Climate to play Cartesian doubt with it, maybe we can ask that they give their realistic assessments of it, or better yet, maybe let them figure out what they want to cover since they’ve got the degrees and seem to be pretty good at figuring that out all for themselves – and we can raise other points relevant to what is being discussed at the time. But in any case, I think going over the report chapter by chapter, as they intend, will provide the discussion with some structure – and it may even give us the chance to examine what the report actually states. Any critique can be done in relation to its actual content at the time that we are actually going over the relevant part. Then if we think there are other important topics which didn’t fit into the structured discussion, maybe we can turn to them at the end.

    Just my two cents…

    Comment by Timothy Chase — 1 May 2007 @ 7:21 PM

  99. Timoothy Chase (#78 again):

    Here are two links on sea ice age:

    http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/8859/28759/01291384.pdf?arnumber=1291384

    http://seaice.apl.washington.edu/IceAge&Extent/

    I may have seen a brief article about the first one in IEEE Spectrum.

    Comment by Jim Crabtree — 1 May 2007 @ 7:26 PM

  100. Well low and behold, section 7.3.2.2.3 of the IPCC AR4 Report “Residual Land Sink” cites the same paper and comes to the same conclusions as the misleading, laughable, PR advocacy, cherry picking, Exxon-Mobil funded, fossil fuel duping CO2Science site.

    Rather than making ad hominem attacks on the authors, perhaps we can deal directly with the science involved.

    Comment by B Buckner — 1 May 2007 @ 9:06 PM

  101. The Second Draft for WG1 from several months ago said the following in Chapter 8 (Climate Models and Their Evaluation), Question 8.1: “As a consequence, models continue to display a substantial range of global temperature change in response to specified greenhouse gas forcing (refer Chapter 10), To date it has not been possible to quantify how errors in a model’s simulation of specific climate observations impact on errors in its future climate projections, but a few studies suggest this may be possible in the future. Despite such uncertainties,…”

    In the final version that was just released this was changed to the following:

    “Consequently, models continue to display a substantial range of global temperature change in response to specified greenhouse gas forcing (see Chapter 10). Despite such uncertainties,…”

    The key phrase eliminated here is “it has not been possible to quantify how errors in a model’s simulation of specific climate observations impact on errors in its future climate projections.” In effect, didn’t the Second Draft said that we can’t quantitatively bound errors in climate forecasts generated by global climate models?

    Why was this eliminated? Did some new research become available or better understood?

    [Response: I’d guess it was because it just didn’t fit. The previous sentence says there are uncertainties, and the next explains what is robust. The missing sentence is related to a distinct issue which is to what extent errors in climatology lead to errors in projections, or even if they do to any significant extent. That is dealt with more comprehensively in Chapter 10. Your rephrasing of the sentence is not the same thing at all. – gavin]

    Comment by Jim — 1 May 2007 @ 9:17 PM

  102. RE#42, stephen – current estimates are still for a nuclear plant to take some 5-10 years to construct, and the point is that it’s better to invest in solar cell manufacturing (which produce sources of power, not just power) than in new nuclear facilities. As far as the 70’s versus today, there is nuclear construction going on in India, and individual plant investments are still around 3.5 billion $US. This is still better than using coal for electricity generation, but in the long run nuclear fission is a dead-end technology. The solar resource is far larger and mostly untapped, in contrast to nuclear (~20% of current US electricity generation). Why doesn’t it make sense to boost solar to the same level as nuclear?

    RE#78 – Timothy, I have to admit that that was a quote lifted from the IPCC report. The issue is very complicated what with black carbon and the effects of stratospheric vs. tropospheric aerosols, as you point out.

    RE#100 – CO2 effects on plant growth are well studied and the fact is that there is no evidence that a warming, high CO2 world will result in higher crop yields for a number of reasons: drought, heat waves, nitrogen and phosphorous limitation, etc. It was thought that the increase in CO2 would offset crop losses due to climate change, resulting in a zero-sum effect, but that’s not supported by real-world experiments: Food for Thought: Lower-Than-Expected Crop Yield Stimulation with Rising CO2 Concentrations, Long et al Sci 2006.

    To quote from the science magazine summary: “Although rising CO2 levels may reduce global crop yields through the effects of higher temperatures and decreased soil moisture, arguments have been made that direct fertilization effects will more than offset these losses. Long et al. (p. 1918; see the Perspective by Schimel) present a critical analysis of data on which the Intergovernmental Panel for Climate Change base their projections that elevated CO2 will have a fertilizing effect. The original estimates came from experiments conducted in the 1980s in greenhouses and sheltered enclosures. More sobering figures are derived from open-field studies in which increased CO2 levels enhanced crop yields ~50% less than in enclosure studies.”

    Keep in mind that the IPCC report doesn’t include recent research, and is a valuable reference but not the last word on the topic of climate change.

    Comment by Ike Solem — 1 May 2007 @ 10:14 PM

  103. IPCC AR4 Report. Ok.

    In #71, Ray Landbury states,

    Trevor, CO2 stimulates plant growth only to the extent that there are no other limiting factors. I believe Hank posted on this several posts back. The short answer is that it’s mixed. Some plants do better and some do worse. As I recall, weeds thrive. So, yes, this has been looked at.

    The other misunderstanding reflected by your post is that unless the plant growth involved is dominated by long-lived woody plants, there isn’t much increase in long-term sequestration of carbon. Indeed, as the plants die and decay, a lot of the carbon goes back into the system as CH4, and so actually increases greenhouse efficiency. This straw has been grasped at repeatedly, and hasn’t supplied much bouyancy so far.

    Comment by ray ladbury â?? 1 May 2007 @ 8:25 am

    In #86, B. Buckner states,

    In #71 you discuss stimulated plant growth and the lack of long-term sequestation of carbon that results from the increased growth. There is actually quite a bit of information to the contrary. The article below is a good place to start.

    http://www.co2science.org/scripts/CO2scienceB2C/articles/V10/N18/EDIT.jsp

    Later, in #100, B. Buckner states,

    Well low and behold, section 7.3.2.2.3 of the IPCC AR4 Report “Residual Land Sink” cites the same paper and comes to the same conclusions as the misleading, laughable, PR advocacy, cherry picking, Exxon-Mobil funded, fossil fuel duping CO2Science site.

    Rather than making ad hominem attacks on the authors, perhaps we can deal directly with the science involved.

    Looking at section 7.3.2.2.3, it states:

    Recent studies of the carbon balance of study plots in mature, undisturbed tropical forests (Phillips et al., 1998; Baker et al., 2004) report accumulation of carbon at a mean rate of 0.7 ± 0.2 MgC ha-1 yr-1, implying net carbon uptake into global Neotropical biomass of 0.6 ± 0.3 GtC yr-1. An intriguing possibility is that rising CO2 levels could stimulate this uptake by accelerating photosynthesis, with ecosystem respiration lagging behind. Atmospheric CO2 concentration has increased by about 1.5 ppm (0.4%) yr-1, suggesting incremental stimulation of photosynthesis of about 0.25% (e.g., next yearâ??s photosynthesis should be 1.0025 times this yearâ??s) (Lin et al., 1999; Farquhar et al., 2001). For a mean turnover rate of about 10 years for organic matter in tropical forests, the present imbalance between uptake of CO2 and respiration might be 2.5% (1.002510), consistent with the reported rates of live biomass increase (~3%).

    As such, plants may act as a sink for the sequestration of carbon – just as CO2Science claims.

    However, looking at the following paragraph, section 7.3.2.2.3 also states:

    But the recent pan-tropical warming, about 0.26°C per decade (Malhi and Wright, 2004), could increase water stress and respiration, and stimulation by CO2 might be limited by nutrients (Chambers and Silver, 2004; Koerner, 2004; Lewis et al., 2005; see below), architectural constraints on how much biomass a forest can hold, light competition, or ecological shifts favouring short lived trees or agents of disturbance (insects, lianas) (Koerner, 2004). Indeed, Baker et al. (2004) note higher mortality rates and increased prevalence of lianas, and, since dead organic pools were not measured, effects of increased disturbance may give the opposite sign of the imbalance inferred from live biomass only (see, e.g., Rice et al., 2004). Methodological bias associated with small plots, which under-sample natural disturbance and recovery, might also lead to erroneous inference of net growth (Koerner, 2004). Indeed, studies involving largearea plots (9-50 ha) have indicated either no net long-term change or a long-term net decline in above ground live biomass (Chave et al., 2003; Baker et al., 2004; Clark, 2004; Laurance et al., 2004), and a five-year study of a 20 ha plot in Tapajos, Brazil show increasing live biomass offset by decaying necromass (Fearnside, 2000; Saleska et al., 2003).

    (Emphasis added.)

    This would seem to be precisely the point that Ray Landbury was making in #71.

    Cherry-picking.

    Comment by Timothy Chase — 1 May 2007 @ 10:46 PM

  104. Re: 101

    Gavin,

    Thanks for your immediate response.

    If the issue being addresses in this point was “a distinct issue which is to what extent errors in climatology lead to errors in projections, or even if they do to any significant extent”, is there some known bound on this error, or is it an undefined potential error?

    Can you point me to the portion of Chapter 10 where it is addressed?

    Thanks in advance.

    Best,
    Jim

    Comment by Jim — 1 May 2007 @ 10:48 PM

  105. Ike Solem wrote (#102 in response to #100):

    Keep in mind that the IPCC report doesn’t include recent research, and is a valuable reference but not the last word on the topic of climate change.

    I completely agree.

    However, judging from what I uncovered in #103, they seem to have done a very good job of anticipating the more recent research.

    Nice.

    Thank you for bringing the article to our attention – it is good to see that sort of confirmation.

    Comment by Timothy Chase — 1 May 2007 @ 11:56 PM

  106. Jim wrote (#104):

    If the issue being addresses in this point was “a distinct issue which is to what extent errors in climatology lead to errors in projections, or even if they do to any significant extent”, is there some known bound on this error, or is it an undefined potential error?

    Can you point me to the portion of Chapter 10 where it is addressed?

    I would recommend “10.5 Quantifying the Range of Climate Change Projections.” In essence, what we are dealing with are a hierarchy of models, some wider, yet coarser (due to limitations on computational power), others narrower and more detailed. Then with parametrization it is possible to make probablistic projections, compare these against the evidence by means of Bayesian analysis, fine-tune the narrower, more detailed theories by adjusting their parameters and use these to adjust the wider, less detailed theories. Or so it would appear from my first skimming of the first section.

    Comment by Timothy Chase — 2 May 2007 @ 1:21 AM

  107. Re #80 Where Tamino wrote “Let’s all face the truth: global cooling from the 40s to the 70s is a myth.”

    The dispute is not about whether there was cooling during the 1970s. It is whether there was a scare about an impending ice age. That is not a myth. William Connolley has documented the evidence very well, though his spin on it all is highly questionable. See the comment by the science author Nigel Calder at: http://www.wmconnolley.org.uk/sci/iceage/calder.html

    As far as the cooling in the 1970s goes, the Northern Hemisphere was cooling at the start of the 1970s when the scare started. See http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif

    Of course thhe NH is where the scientists lived. This only makes more clear the point I am trying to make. Scientists do make mistakes. In the early 1970s they could see the world around them cooling and deduced that it would continue and was global, despite the fact that the southern hemisphere was warming.

    But you too are making a mistake. Glacial periods are driven by the positive ice-albedo feedback from advancing NH ice sheets. Thus changes in global temperatures need not necessarily be the best guide to future climate. This was discussed here: Does a Global Temperature Exist? Therefore, in Earth Science, where the systems under discussion are fractal and chaotic, it is wrong to apply simple mathematical techniques such as linear trends and Bayesian logic to make predictions.

    So, using a linear trend to estimate the size of the future Arctic sea ice sheet is a simplification too far. The winter trend is different from the summer trend, and so is the annual trend. Brooks showed that there is a tipping point, where if the size of the summer ice drops below a minimum value then the winter ice can not reform. Without that ice, the Earth’s thermostat is broke. How high will temperatures rise then, and how far from the North Pole will be affected?

    Think about it! Mathematics is not the answer to a world in crisis!

    Comment by Alastair McDonald — 2 May 2007 @ 3:46 AM

  108. IS IT TOO LATE TO PREVENT WHAT IS KNOWN AS “DANGEROUS” CLIMATE CHANGE

    Fact number one aboout climate change is politicians in the UK seem to keep on referring to CO2 levels and not greenhouse gas levels. Greenhouse gases currently reside at 459 ppmv whilst CO2 levels are 380 ppmv. Is this true ? It is according to George Monbiot, a well known UK left wing environmentalist.

    He then goes on to tell us that the IPCC projections for the alleged 2 C of warming “so called dangerous climate change becuase it is then out of our hands” are around 510 ppmv CO2 equivilent so there is way on earth then this is going to be met considering that it is going to take another 50 ppmv before any of this changes in any discernable and another 50 ppmv after that until we have any solution.

    James Hansen tells us that it can be done if we (USA I believe) do not burn anymore coal but that is just not realistic unfortunately and sequestration does not exist in commercial forms as yet and the USA wants to build 159 new coal fired powerstations starting soon that this technology exists.

    Just how long do the people of real climate believe they have to stop the so called 2 degree celcius threshold?

    The aeticle can be found here: http://www.monbiot.com/archives/2007/05/01/1058/. I am presuming that in the main his deliberations on greenhouse gas levels are correct.

    Comment by pete best — 2 May 2007 @ 3:49 AM

  109. cce — Spencer Weart’s “The Discovery of Global Warming” (2003) is a good one, and if I’m not mistaken you can buy used copies on Amazon for as little as $2.49. It’s also available on-line somewhere for free, but I don’t have the URL offhand.

    John Houghton’s “Global Warming: The Complete Briefing” (2004) is another good one.

    Comment by Barton Paul Levenson — 2 May 2007 @ 5:59 AM

  110. Re #62 — the effect from doubling CO2 by itself is to raise the ground temperature by about 1.2 K. But with feedbacks like water vapor and ice/albedo, this goes to about 3.0 K, just like the IPCC says.

    Comment by Barton Paul Levenson — 2 May 2007 @ 6:01 AM

  111. Re #73 — Ray has a point. I often cite data without telling anyone where I got it from. I’ll try to cite sources from now on. On peer-reviewed journal articles, I’ll try to give the whole citation, if I can remember it or look it up.

    Comment by Barton Paul Levenson — 2 May 2007 @ 6:05 AM

  112. Re #80 and [[Let’s all face the truth: global cooling from the 40s to the 70s is a myth. ]].

    Tamino, I am reluctant to disagree someone who is much better at statistical analysis than I am, but I think that climatologists in general do tend to portray 1940-1970 as an era of cooling. My guess is that it’s not exactly when temperatures were declining that was the issue, but the overall slope for that period compared to the overall slope for earlier and later periods. There is definitely a discontinuity in the graph in this area. Inspecting it visually, it’s hard not to treat 1940-1970 as a distinct period:

    http://data.giss.nasa.gov/gistemp/graphs/

    If you want to rename it as “global temperature stasis” rather than “global cooling” you might have a point.

    Comment by Barton Paul Levenson — 2 May 2007 @ 6:11 AM

  113. [[I was asked to ask you good people whether you think the Hiroshima/Nagasaki/above ground A-bomb tests might have generated enough airborne debris to contribute significantly to the cooling effect ]]

    Almost certainly not.

    Comment by Barton Paul Levenson — 2 May 2007 @ 6:13 AM

  114. Re: Temperature anomalies from 1940-1975. Whether you call it cooling or simply a hiatus in the warming, there certainly was something anomalous about the period. There are a number of things that make it a little difficult to attach a label. First, the 1930s and early 40s saw accelerated warming compared to previous decades–perhaps a product of emerging from the depression and this was followed in the latter part of the 40s by a definite cooling trend lasting a few years. However, how prominent this trend is depends on the dataset you look at–it’s much more evident in the land-ocean index than in meteorological stations.
    Historically, there were some scientists who expressed concern about the cooling, probably with an eye on the end of the interglacial. There were also some who attributed the cooling to aerosols–a viewpoint supported by current models.
    What is certainly true is that there was nothing like the overwhelming consensus we now see. The warming is indisputable, and the only cause that comes close to explaining is anthropogenic ghg emissions.

    Comment by Ray Ladbury — 2 May 2007 @ 8:12 AM

  115. Alastair McDonald (#107) wrote:

    But you too are making a mistake. Glacial periods are driven by the positive ice-albedo feedback from advancing NH ice sheets. Thus changes in global temperatures need not necessarily be the best guide to future climate. This was discussed here: Does a Global Temperature Exist? Therefore, in Earth Science, where the systems under discussion are fractal and chaotic, it is wrong to apply simple mathematical techniques such as linear trends and Bayesian logic to make predictions.

    So, using a linear trend to estimate the size of the future Arctic sea ice sheet is a simplification too far. The winter trend is different from the summer trend, and so is the annual trend. Brooks showed that there is a tipping point, where if the size of the summer ice drops below a minimum value then the winter ice can not reform. Without that ice, the Earth’s thermostat is broke. How high will temperatures rise then, and how far from the North Pole will be affected?

    But they aren’t using simple linear trends. They are modeling non-linear behavior through each day of each year, and making use of a rapidly expanding wealth of data against which their theories can be tested through both predictions and postdictions. Bayesian methods may then be applied. Then as more data becomes available the process can be repeated reiteratively.

    Think about it! Mathematics is not the answer to a world in crisis!

    Of course not.

    But it is half of the answer. The first half.

    Comment by Timothy Chase — 2 May 2007 @ 9:18 AM

  116. > Spencer Weart’s “The Discovery of Global Warming” …available on-line …
    It’s in the sidebar, right side of the page:
    Science Links
    * AIP:Discovery of Glob. Warm.

    Comment by Hank Roberts — 2 May 2007 @ 11:16 AM

  117. Re #115

    Timothy, you obviously have not being studying the poster linked by SCM at http://cires.colorado.edu/events/members/posters/2007/I25M.pdf

    Figure 1 shows attempts to linearise sea ice extent, and Figure 2 shows how the predictions have failed.

    The Summary states “… none or very few individual model simulations show trends comparable to observations.” and “… the IPCC models underestimate the GHG response …”

    The scientists overestimated teh danger in the 1970s but now they are under estimating it :-(

    Comment by Alastair McDonald — 2 May 2007 @ 11:21 AM

  118. Love to see comments on Cockburn’s summary of Hertzberg’s position

    Comment by Larry — 2 May 2007 @ 12:37 PM

  119. Re: linear trends

    It should be emphasized that using linear regression to test for a trend does not assume, or impose, or rely on, the existence of a linear trend. In fact the trends which are so detected are almost never linear.

    The real purpose of linear regression for trend testing, is to test the null hypothesis: that there is no trend (of any kind). If the linear regression gives a statistically significant result, then we haven’t proved a linear trend — all we’ve proved is that there is some trend rather than none. Unfortunately, even many scientists don’t really appreciate this fact.

    One of the reasons for the popularity of linear regression for trend testing, is that it is a very sensitive test. Most trends, no matter what the type, will give a statistically significant response to linear regression, and the regression rate will be indicative of the size of the trend. Another reason for its popularity is that its statistical properties are well understood.

    Actually demonstrating that a given trend is linear, is an enormously more difficult statistical procedure.

    Comment by tamino — 2 May 2007 @ 12:41 PM

  120. Is there any email address for correction if I see typos in the report?

    Comment by L — 2 May 2007 @ 1:14 PM

  121. Re #103 and prior: As discussed in the other current thread on CO2 measurement, large urban areas tend to have distinctly higher levels of CO2, on the order of 50-100 ppm more than the global average. If there were a significant CO2 fertilization effect that would dominate other environmental factors, it seems to me that one would expect to see the results in those urban areas. Admittedly this is not a scientific assessment, but I sure haven’t noticed anything in my garden (Oakland, CA), or in the vegetation in the small urban park adjacent to my house, or in the extensive park system running up and down the spine of the East Bay hills. OTOH, the University of California does maintain an experimental agricultural station not far from where I live, so presumably they would have been in a position to notice something. I suppose one could respond that other environmental factors accompanying the CO2 increase might have acted to limit the effect. Indeed.

    Re #107: “Brooks showed that there is a tipping point, where if the size of the summer ice drops below a minimum value then the winter ice can not reform.” Alastair, could you provide a pointer to the source for that? Thanks.

    Comment by Steve Bloom — 2 May 2007 @ 2:10 PM

  122. Here are several including one here at RC:
    http://www.google.com/search?hl=en&q=Brooks+++%22Arctic+sea+ice%22++reform&btnG=Search

    Comment by Hank Roberts — 2 May 2007 @ 6:54 PM

  123. #121 – Steve Bloom:

    You might want to check the pollen count. (Your local environmental people probably have records going back 10+ years). Pollen count here in the SE US has been increasing for some number of years. Also, think about this – most plants probably don’t know how to respond to increased CO2 since it is higher now than it has been in over 650K years. Posion ivy does – see the following link.

    http://news.nationalgeographic.com/news/2006/05/060530-warming.html

    There are over vines that also respond in a similar way to CO2 fertilization. Haven’t seen anything on how kuzdu responds.

    Comment by Jim Crabtree — 2 May 2007 @ 7:30 PM

  124. I hate to change the subject but has anyone heard of anything coming out of the FSU Andrill Workshop?

    Anyone in the know blogging out of there?

    http://www.andrill.org (Check out the Betty Blog!)

    http://www.fsu.edu/news/2007/04/25/global.warming/

    Comment by Thomas Lee Elifritz — 2 May 2007 @ 8:45 PM

  125. Alastair McDonald (#117) wrote:

    Timothy, you obviously have not being studying the poster linked by SCM at http://cires.colorado.edu/events/members/posters/2007/I25M.pdf

    Figure 1 shows attempts to linearise sea ice extent, and Figure 2 shows how the predictions have failed.

    The Summary states “… none or very few individual model simulations show trends comparable to observations.” and “… the IPCC models underestimate the GHG response …”

    The scientists overestimated the danger in the 1970s but now they are under estimating it.

    That doesn’t exactly look like they were attempting linear modeling.

    However, you are right – the ice appears to be melting about 50% faster than our models would predict. This was brought up by either Gavin or Eric a little bit ago. In any case I agree that it would seem there is plenty to worry about, but I honestly don’t think that climatologists are (by-and-large) underestimating the seriousness of the problems we face. Rather, they are having difficulty modeling them – particularly in the case of ice. Complicated stuff. Its a learning process. Moreover, if they could change policy, undoubtedly they would. But it isn’t up to them. They have to convince others – and better modeling will help in this regard.

    In any case, thank you for the link.

    I am quite interested in this area – for a number of reasons. For example, what is the likelihood of a catastrophic collapse of a given ice shelf? How long can we actually expect arctic ice to last? What will rising temperatures in the arctic mean for oxygen circulation in the ocean? The carbon cycle? What about shallow methane hydrates? These are all linked – and each will have important ramifications.

    Comment by Timothy Chase — 2 May 2007 @ 8:46 PM

  126. tamino, I possibly could accept your statistical analysis, but why is the literature rife with graphs that show (all with wobbles) level global temps from 1870 to 1900, an odd drop from 1900-1910, a fairly decent steady rise from 1910 to 1940, a modest but definite drop (about 0.1 degreeC) from 1940 to 1970, and a rise from 1970 or so on. There must be hundreds of ‘em. How can that be?

    Comment by Rod B. — 2 May 2007 @ 9:40 PM

  127. >Andrill
    I’ve been asking too; last I heard, the last ice cores are on a ship somewhere. There were a few news stories (Google News turns up a couple new since the last time I checked). Big meeting happening right now.

    Digital data should be available here:
    http://www.arf.fsu.edu/digitaldataCP.cfm
    http://www.arf.fsu.edu/Data/CorePhoto.pdf

    Comment by Hank Roberts — 2 May 2007 @ 10:12 PM

  128. Re #102: […in the long run nuclear fission is a dead-end technology.]

    In the long run, so is solar. The sun will be too dim in what, only a billion years or so? So strictly speaking, both technologies are dead ends, but only after periods that are far longer than the likely span of human civilization.

    [The solar resource is far larger and mostly untapped, in contrast to nuclear (~20% of current US electricity generation). Why doesn’t it make sense to boost solar to the same level as nuclear?]

    We’ve been through this before, at length. It’s not a case of one versus the other. It does make sense to boost solar, and use it wherever it is practical. The problem is that there are a lot of places and uses for which it is not practical. We need solar and nuclear – and geothermal, wind, biomass, and whatever else people can think of.

    Comment by James — 2 May 2007 @ 11:53 PM

  129. Re: 81

    Let’s all face the truth: global cooling from the 40s to the 70s is a myth

    Not in the Arctic (or Greenland) it isn’t.

    Incidentally what has happened to the GISS station data – I can’t access it now?

    Also how is the 5.35xln(..) formula for CO2 forcing determined?

    thanks

    Caz

    Comment by Caz — 3 May 2007 @ 5:08 AM

  130. Hello again,

    I’m trying to reconcile some figures in an argument about solar variability. Unfortunately, I’m a base layman – if anyone troubles to help, I’d very much appreciate it.

    http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Ch02.pdf – p. 191

    From table 2.10 in IPCC AR4WG1, figures for ten studies are given between 0 and 0.68(Wm-2) for the period from the Maunder Minimum. Best estimate IPCC figure of 0.12(m-2) falls roughly in the middle of the last three figures given in that table. Is it that the range of these 3 are solely employed because they excluded “original stellar brightness distribution, or the use of the brightness reduction in the Baliunas and Jastrow”? The argument I’m having is about the validity of “ignoring” or dismissing the higher figures.

    The highest figure in the table, 0.68 (Wm-2), came from Solanki and Fligge
    (1999). Looking at more recent studies by Solanki (and colleagues), I’m trying to figure out how to translate a figure cited by Solanki and Krivova (2004) http://www.mps.mpg.de/projects/sun-climate/papers/solphys-2004.pdf. To whit;

    “On a longer (and for climate studies more important) time scale things are less
    certain. The cyclic component of irradiance variations can be reconstructed back
    up to 1610, although with decreasing reliability and accuracy at earlier times. The
    magnitude of any secular trend remains a matter of intense debate. A recent, careful
    estimate by Foster and Lockwood (2004) gives a value of only 1.7Wmâ��2.”

    Is 1.7Wm�2 measuring solar variance from MM as per the 2.10 chart? (And if so, how come it is 2.5 times higher than the highest figure therein?) The 2004 Solanki/Krivova paper study rejects Baliunas and Jastrow (which was included in the Solanki/Fligge (1999) calculations via Lean et al (1995) as far as I can make out), and acknowledges that solar variance estimates have trended downwards in light of recent studies. I noticed a figure given in a 2007 Balmaceda Krivova Solanki study at 1.3 (http://adsabs.harvard.edu/abs/2007astro.ph..3147B);

    “The model predicts an increase in the total solar irradiance since the Maunder Minimum of about 1.3 rm{Wm$^{-2}$}” [That last equation looks like gobbledygook to me]

    From a Solanki/Fligge ‘high’ of 0.68 (Wm-2) in IPCC AR4WG1, to a more recent figure that is ‘only’ 1.72 Wm-2 (cited in what seems to be a crestfallen tone by Solanki and friends).

    Perhaps the IPCC figure 0.12 is not measuring from MM? But lo, it appears in the section 2.7.1.2 Estimating Past Solar Radiative Forcing.

    How do I relate these figures? Why do Solanki and colleagues lately imply that solar variance is less than ‘most previous estimate’, yet supply what appear to be higher figures? If this is too baby to deal with, I’m very good at following links. :)

    Cheers,

    Comment by barry — 3 May 2007 @ 5:26 AM

  131. [[ We need solar and nuclear – and geothermal, wind, biomass, and whatever else people can think of. ]]

    No, we don’t. We need that mix, or another mix that leaves one or more of those components out — like nuclear. I don’t think we have to have any individual component. There are a number of ways to power society without fossil fuels.

    Comment by Barton Paul Levenson — 3 May 2007 @ 5:40 AM

  132. Someone linked my name in a previous post (#18) to a “damn spammer” writing. Perhaps because I posted the URL of a wiki? I hardly conceive it could be seen as spamming, and -as far as I know- only God knows whether I’m damned or what.

    However, let me put that argument in a way that does not hurt anyone’s sensibility.

    Pete Best (#21) correctly pointed out that there are places, e.g., USA, where Anthropogenic Global Warming is not yet a fact given for granted.
    Real Climate is doing a TERRIFIC job about that (by the way, thanks!), but it seems to me it usually drifts technical. Most non-educated people probably would find difficult to follow it.

    So I wonder if scientist, pricipally those who know better this IPCC report, should find other ways to reach those people.

    I’m sure many give public conferences, or go to radio stations, and so on. I do so, at a local scale.

    I’d like to suggest another way to reach less-educated people may be considered, which is posting in widely read wikis, in a style understandable by somehow less educated people than Real Climate readers. Some wikis can guarantee that well written articles are not screwed by other contributors, others cannot. However, when yo type a “difficult word” in Google to look for a definition, the most famous wiki very often appears in the first page. This implies many read it. This implies reaching the bulk of people surfing the internet.

    Is someone already doing it? Is this responsability of scientists? Dunno, but I often ask myself when the things I do start to have public relevance, as the IPCC reports surely have.

    Comment by Nereo Preto — 3 May 2007 @ 6:23 AM

  133. Re #128 Actually, the sun is getting brighter, not dimmer. I’ve seen it hypothesized that over geological time, the brightening sun speeds up the erosion-driven carbonate-silicate cycle, reducing atmospheric CO2 levels – and that this temperature-stabilising feedback will fail in 600-1000 million years, after which the oceans will boil and we’ll have a true runaway greenhouse effect (time for the orbital mirrors in the unlikely event anyone is there to put them up). As for “We need solar and nuclear – and geothermal, wind, biomass, and whatever else people can think of.”, well there are complementarities between some of these, but there is also competition between them for R&D resources including skilled labour, government subsidies and economies of scale. We need to determine which of them, in what mix, will give the best results, in relation to climate change, and whatever other advantages and drawbacks they have.

    Comment by Nick Gotts — 3 May 2007 @ 6:29 AM

  134. Re: #126 (Rod B.)

    … why is the literature rife with graphs that show (all with wobbles) level global temps from 1870 to 1900, an odd drop from 1900-1910, a fairly decent steady rise from 1910 to 1940, a modest but definite drop (about 0.1 degreeC) from 1940 to 1970, …

    Let’s look at some of those graphs. When it comes to estimating global average temperature, I think we’d agree that the two “big guns” are NASA GISS and HadCRU. Here are their graphs:

    http://data.giss.nasa.gov/gistemp/graphs/Fig.A2_lrg.gif

    http://www.cru.uea.ac.uk/cru/info/warming/

    Examine the time interval 1950 to 1970. There’s no visible warming in either the GISS or HadCRU graphs. When you run the numbers, there’s no significant trend in the numerical analysis either. In fact, even if you don’t take into account the autocorrelation of the data, there’s still no trend — it’s not even close.

    If you focus on the time interval 1940 to 1970, there’s a distinct drop in the late 40s, followed by reasonably constant temperatures 1950 to 1970. The point I’m trying to make is that “cooling for 7 years followed by flat-as-a-pancake for two decades” does not constitute three decades of cooling.

    I don’t dispute that it was cooler in 1970 than in 1944. But that most assuredly does not mean that we had cooling from 1940 to 1970. I think this is one of those myths that was simply never called into question, so it’s become a scientific “urban legend.”

    How did this come about? Looking at the entire data set (GISS or HadCRU), it’s not unnatural to isolate the time interval 1940 to 1970 (although 1944 to 1975 is a better choice). If you do a linear regression on that data, and you fail to account for the autocorrelation of the data, then you get a significant trend. But first, when autocorrelation is included, the trend is found not to be significant. Second, as I said in an earlier post, a statistically significant result from linear regression does not establish linearity of a trend (it simply contradicts the absence of a trend). “Global cooling from 1940 to 1970″ doesn’t stand up to close scrutiny.

    Comment by tamino — 3 May 2007 @ 7:15 AM

  135. Re 126, Rod, I sort of address this in a previous post. Basically, I would not trust any trend that doesn’t emergy in the 5 year averages. Moreover, note that the “cooling” depends a lot on which measure you look at–it’s a lot clearer in some than others. Part of the problem is that you had a seeming upsurge in temperature in the late 1930s and early 1940s and then a drop after about 1944. Then things look pretty flat for about 20-30 years. Actually, I would argue (and I emphasize this is purely a SWAG on my part) that this looks like what one might expect if the positive forcer (CO2) and the negative forcer (aerosols, say) had the same time dependence–e.g. if they were both the result of fossil fuel burning. After about 1975, we took the particulates and unburned hydrocarbons out of the equation and warming resumes.
    I’d be very interested to see what solar forcing looked like in the period, say, 1937 to 1944. Finally, note that in contrast to the ambiguity of the trend from 1944-1975, the recent warming is indisputable, independent of which dataset you look at or how you analyze it.

    Comment by Ray Ladbury — 3 May 2007 @ 8:15 AM

  136. My post #130 looked fine in preview, but comes out badly formatted, compounding my own lack of clarity. Let me try again. I get the impression that solar forcing is a weary subject for the hosts here – apologies. I have read some of the posts on the subject at realclimate and elsewhere, but could not find the answers to my rather specific questions.

    I get the following from AR4WG1 IPCC (pp 189 – 193)

    http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Ch02.pdf

    1. Table 2.10 (p. 191) gives ten values (various studies) for RF since the Maunder Minimum M to present (roughly), the lowest being 0 Wm-2 (Dziembowski et al. 2001) and the highest being 0.68 Wm-2 (Solanki and Fligge 1999).

    2. IPCC best estimate for RF from solar radiance increase, from Maunder Minimum to present, is 0.12Wm-2. This is less than half the value given in the previous IPCC assessment. It is also much less than the mean/average of the ten studies in the table.

    3. The reason the best estimate value is much lower than the mean is that inputs in most/all of the high range studies have been thrown into doubt.

    (p 190)

    “The motivation for adopting a long-term irradiance component was three-fold. Firstly, the range of variability in Sun-like stars (Baliunas and Jastrow, 1990), secondly, the long-term trend in geomagnetic activity, and thirdly, solar modulation of cosmogenic isotopes, all suggested that the Sun is capable of a broader range of activity than witnessed during recent solar cycles…

    Each of the above three assumptions for the existence of a significant long-term irradiance component is now questionable….” [etc]

    It seems to me that the RF values of the earlier studies, which employed one or all of the above three assumptions, have been excluded. IPCC best estimate 0.12Wm-2 falls between the last three studies.

    Foster (2004) 0.23 Wm-2

    Y. Wang et al. (2005) 0.10 Wm-2

    Dziembowski et al. (2001) 0.00 Wm-2

    Am I correct in assuming these values are the only ones considered valid out of the ten in the table? I had assumed some process of ‘grading’ each study for validity had been undertaken, but then I checked the 2001 IPCC Assessment and found the best estimate at that time was (seemingly) derived by running a line through the middle of the range. Was the 0.12 estimate derived much differently?

    I checked out some later Solanki (and colleagues) studies. Here is where I became really confused.

    Solankia and Kirvova (2004) state that they, like the latest IPCC, have excluded the inference from sun-like stars (Baliunas and Jastrow, 1990) that underpinned later studies (Lean et al. 1995, which Solanki and Fligge 1999 had employed). They implied that a lower RF was the result.

    http://www.mps.mpg.de/projects/sun-climate/papers/solphys-2004.pdf

    Excerpts;

    “The original stellar evidence of Baliunas and Jastrow was not conclusive and it has been called into question by recent studies. The debate on this issue is ongoing, so that at present stellar data are not a reliable guide for the magnitude of the secular variation….”

    “Probably the most sophisticated reconstruction including a secular trend is due to Foster (2004) and to Foster and Lockwood (2004)…. Finally, using the measured distribution function of the magnetic field at recent epochs and assuming that there were no faculae or network features on the Sun during the Maunder minimum they obtained an upper limit of the increase in brightness of the network since the Maunder minimum of 1.7Wmâ��2. [!!] This is lower than most previous estimates of the secular trend (which, however, were based on a possibly flawed interpretation of stellar data)….”

    “On a longer (and for climate studies more important) time scale things are less certain. The cyclic component of irradiance variations can be reconstructed back up to 1610, although with decreasing reliability and accuracy at earlier times. The magnitude of any secular trend remains a matter of intense debate. A recent, careful estimate by Foster and Lockwood (2004) gives a value of only 1.7Wmâ��2.”

    This value 1.7Wm-2 perplexes me. It is 2.5 times larger than the highest estimate given in AR4WG1, yet the impression from the above is that it represents a value “lower than most previous estimates of the secular trend”.

    A more recent study (Balmaceda, Krivova and Solanki 2007), yields a value of 1.3Wm-2 since MM.

    http://adsabs.harvard.edu/abs/2007astro.ph..3147B

    That’s still 1.9 times greater than the highest value (Solanki and Fligge 1999) in the AR4 chart. Are these figures all representing the same thing (solar RF increase since Maunder Minimum?) If so, why the big jump in Solanki’s later studies, which now exclude inputs that previously resulted in higher RFs?

    I hope this is clearer, and am pretty sure the answer will be that I’ve misunderstood terminology or something.

    In advance of someone schooling me, thanks.

    Comment by barry — 3 May 2007 @ 11:04 AM

  137. Now it is at least 90% probable that human injection of carbon dioxide into the atmosphere is in process of raising world temperatures to intolerable levels. In the previous IPCC assessment report this was rated as very likely.

    Would someone please point out for dunces like me what new evidence derived since 2001 has led to this change from likely to almost certain? I have followed reports supporting the previous assessment report and searched the AR4 for dates of facts supporting the AR4 statement of near certainty. I have found many studies dated before 2001, some ranging in dates from the nineties up to 2002, but not really revealing new facts.

    Comment by Peter Namtvedt — 3 May 2007 @ 5:20 PM

  138. Re #137: Peter Namtvedt — That has been discussed in comments, perhaps in a thread for a earlier topic. As I understand it, considerable new data sets have only become available in the last four years. This seems to have increased the certainty…

    Comment by David B. Benson — 3 May 2007 @ 6:03 PM

  139. Re: #137 (Peter Namtvedt)

    One of the important changes since the last IPCC report is that we have now reconciled the discrepancy between computer models, satellite temperature measurements, and balloon-borne measurements. It turns out that the computer models were basically right, while both the satellite and balloon-borne measurements had hitherto unaccounted errors. This strengthens confidence in computer model results, and resolve what was, as far as I know, the single biggest cause for doubt.

    Comment by tamino — 3 May 2007 @ 6:17 PM

  140. Tamino (et al) says “I don’t dispute that it was cooler in 1970 than in 1944. But that most assuredly does not mean that we had cooling from 1940 to 1970.

    Huh?!!?

    I’m just a simple farm boy (of yesteryear) from Iowa (though with a Math degree). If the temperature is cooler in 1970 than it was in 1940, we kinda think….

    You could argue that it is statistically insignificant and with all of the regression analysis and autocorrelation it might not indicate a general trend. But, and I hate to break it to you, if the temperature drops, IT’S COOLING!

    Comment by Rod B. — 3 May 2007 @ 9:56 PM

  141. Re #133: [Actually, the sun is getting brighter, not dimmer.]

    OK, I stand corrected on solar physics – the sun will get brighter for a while, then it will get dimmer. I was more interested in making a point that still stands, which is that eventually the sun is going to burn up its supply of hydrogen and become a white dwarf (IIRC it’s not big enough to go nova), rendering those solar power plants ineffective, just as we’d eventually run out of fissionable materials to use for power plants. But in both cases, the time needed would be ridiculously long in comparison to the expected life of the human species.

    […there is also competition between them for R&D resources including skilled labour, government subsidies and economies of scale. We need to determine which of them, in what mix, will give the best results, in relation to climate change, and whatever other advantages and drawbacks they have.]

    So you want to study the problem for another decade or two? I’d think a better, and certainly faster, approach would be to recognize that competition is good. Use taxes to price CO2 emissions according to the potential damage they do, remove the artifical barriers and/or or subsidies for particular technologies, and let the market work.

    Comment by James — 4 May 2007 @ 12:29 AM

  142. Tamino (#134) et al:

    If you look at the figures here it is quite clear that there used to be an optically impressive cooling over this interval – I won’t speculate on whether it was “statistically significant” or not – and I think this adequately explains where the “urban legend” came from, even though the data has been subsequently adjusted in such a way as to eliminate this feature.

    Comment by James Annan — 4 May 2007 @ 3:26 AM

  143. Re #141 The difference in timescales between the exhaustion of fissionable materials on Earth and of the sun is many orders of magnitude, so your comparison is somewhat absurd, but I agree with you that the former is not a valid objection to nuclear power over the next few decades – and I’ve never said otherwise here. Where did I say I wanted to study the problem for another decade or two? We need swift inter-governmental agreements on emissions targets, and in practice different governments will take different routes to meeting them, but the measures that can be implemented fastest in rich countries are energy efficiency and demand reduction. I agree we need measures to limit emissions, although I’d favour emissions rationing over taxation. So far as low-carbon energy production is concerned, which methods win out in particular countries will be determined largely by institutional frameworks concerning matters such as planning and insurance, and governmental investment in different forms of infrastructure, which are determined politically – at present, that means largely by which coalition of businesspeople and bureaucrats within a country can most effectively exert pressure, with a minor contribution from public opinion in representative democracies. As for “competition is good” and “let the market work” – belief in that sort of tosh is a large part of how we got into this mess. In capitalist economics, what is most profitable within the current institutional and infrastructural context dictates what is produced – and what is most profitable is often extremely destructive both environmentally and socially. Taxing “negative externalities” like GHG emissions is one way of trying to limit this destructiveness by interfering with markets, but not, at least by itself, a very effective one. When a real emergency is recognised (as in WW2 for example) governments of capitalist countries swiftly drop all the “free market” guff and coordinate production by a mixture of negotiation between interest groups and legal imposition. We’ll know these governments are serious about climate change when they start doing something similar – what we’ll need to do then is make sure the process comes under as much democratic control as possible at all levels from local to global, rather than allowing it to be dominated by big business.

    Comment by Nick Gotts — 4 May 2007 @ 4:25 AM

  144. Re: #140 (Rob B.)

    Tamino’s point was that it cooled sharply early in the 40-70 period but the temperature trend then went sideways for the last two thirds of the period. That’s quite significantly different from a relatively constant descent that is implied by the (strictly accurate) statement of ‘there was a cooling between 1940 and 1970′. Or the less accurate (according to Tamino’s regression analysis) ‘there was a cooling trend between 1940 and 1970′.

    If you’ve ever done mountain sports you’ll know what I mean – a short red followed by a long flat run off is a very different thing to ski or (especially) snowboard compared to a piste that is blue all the way along, even if they both start and end at the same place.

    Regards
    Luke

    Comment by Luke Silburn — 4 May 2007 @ 4:58 AM

  145. #10
    AVERAGE WEATHER (as the statistical description in terms of the mean and variability) and the term CLIMATE does not makes a lot of sense. This can be easily demonstrated when trying to make sense of the term CLIMATE CHANGE (see #2); because any change of statistical description, remain: statistical description, whether one calculates this on months or million years. Which statistics are used and included? So what is CLIMATE?

    Comment by L.R. — 4 May 2007 @ 5:34 AM

  146. Re: #134

    If you focus on the time interval 1940 to 1970, there’s a distinct drop in the late 40s, followed by reasonably constant temperatures 1950 to 1970. The point I’m trying to make is that “cooling for 7 years followed by flat-as-a-pancake for two decades” does not constitute three decades of cooling.

    Using your criteria we haven’t had 3 decades of warming then. we’ve just had some warming – some cooling – some more warming and according to HadCrut (and RSS and UAH satellite) a more or less flat trend in the last decade.

    Comment by Caz — 4 May 2007 @ 6:22 AM

  147. [[OK, I stand corrected on solar physics – the sun will get brighter for a while, then it will get dimmer. I was more interested in making a point that still stands, which is that eventually the sun is going to burn up its supply of hydrogen and become a white dwarf (IIRC it’s not big enough to go nova), rendering those solar power plants ineffective, just as we’d eventually run out of fissionable materials to use for power plants.]]

    Before it becomes a white dwarf, the sun will become a red giant, and then puff off its outer layers in a “planetary nebula.” The latter effect will wipe out any surviving life in the solar system, I believe.

    Comment by Barton Paul Levenson — 4 May 2007 @ 6:53 AM

  148. Re #140 (Rod)

    I’m just a simple farm boy (of yesteryear) from Iowa (though with a Math degree). If the temperature is cooler in 1970 than it was in 1940, we kinda think….

    You could argue that it is statistically insignificant and with all of the regression analysis and autocorrelation it might not indicate a general trend. But, and I hate to break it to you, if the temperature drops, IT’S COOLING!

    I’m just a simple council estate son of a steelworker (of yesteryear) from Wales (with no Maths degree). If the temperature is warmer in 1969 than it was in 1939, we kinda think …

    Yes, step back a year at either end of your chosen time interval: take the years 1939 and 1969 instead. Then, using your definition, state whether “IT’S COOLING!” or it’s warming.

    You could argue it is statistically insignificant (and I’d agree with you, especially as the respective temperature anomalies are -0.001 and -0.01). But, and I hate to break it to you, if the temperature increases, IT’S WARMING!

    Not a lot, I do warrant. But, hey, if cooling is cooling, then warming is warming to my simple way of thinking. ;)

    And what does any of that prove in either case? Why, nothing, except that Tamino is spot on in his assessment.

    Comment by P. Lewis — 4 May 2007 @ 6:57 AM

  149. Re #121

    C.E.P. Brooks’ idea that “the ice pack was balanced on a knife edge” are described here http://www.pibburns.com/smmia2.htm with a full reference, but Mewhinney implies that Brooks ideas were “not supported by any calculation.” In fact Brooks supplied a table which can easily be converted into a calculation using a spreadsheet, now.

    Spencer Weart also cites Brooks:

    ‘The respected climate expert C.E.P. Brooks offered the worst scenario. He suggested that a slight change of conditions might set off a self-sustaining shift between climate states. Suppose, he said, some random decrease of snow cover in northern latitudes exposed dark ground. Then the ground would absorb more sunlight, which would warm the air, which would melt still more snow: a vicious feedback cycle. An abrupt and catastrophic rise of tens of degrees was conceivable, “perhaps in the course of a single season.”(5) Run the cycle backward, and an ice age might suddenly descend.’

    at http://www.aip.org/history/climate/rapid.htm#M_5_ also with a full reference.

    HTH,

    Cheers, Alastair.

    Comment by Alastair McDonald — 4 May 2007 @ 9:13 AM

  150. Re #139:

    One of the important changes since the last IPCC report is that we have now reconciled the discrepancy between computer models, satellite temperature measurements, and balloon-borne measurements. It turns out that the computer models were basically right, while both the satellite and balloon-borne measurements had hitherto unaccounted errors. This strengthens confidence in computer model results, and resolve what was, as far as I know, the single biggest cause for doubt.

    I asked this in another locale, and the person I was trying to make this point to didn’t understand the objective —

    Has anyone validated the current models against an “assumed”, average solar radiance, CO2 increase, volcanic activity, etc. for the 20th century and arrived at the same values as where we are today (or, at least, were in 2000)?

    [Response: See http://www.realclimate.org/index.php/archives/2005/05/planetary-energy-imbalance/ – gavin]

    I have other issues with the IPCC report and projections, although I must admit that the recent find of 100 billion BBLs of oil in Western Iraq, and the US government’s recent declaration that Canada has (I think …) nearly 180 billion BBLs of reserves is slowly eroding my primary objections. I’ve not look at what’s been proven in the Orinoco sands, but if it’s another 180 billion BBL, I think we’re going to be in more trouble, climate wise, than I’ve been willing to accept in the past.

    Comment by FurryCatHerder — 4 May 2007 @ 9:19 AM

  151. Rod,
    As I said above, the significance of the “cooling” depends on which metric you look at. The meteorological stations show it more than the land-ocean metric. Even with the meteorological stations it is hard to know whether what you are looking at is anomalously high warming in the late ’30s and early ’40s, followed by a single fairly dramatic drop until 1950 and flat trends from 1950-1975. Note that all of the data are consistent with an aerosol driven cooling due to burning of fossil fuels. I’m afraid I agree with Tamino: It is a very different thing to say that 1970 was cooler than 1944 than it is to say there was a 30 year cooling trend. The latter is simply no supported by any reasonable analysis of the graph. Climateaudit and others are guilty of graphsmanship at the very least. In any case, this is all a red herring. I don’t know of anyone who disputes that we are warming significantly now–at least not anyone I’d let play with a sharp object.

    Re 145. L.R. Please. Now, we’re going to get into the whole “climate doesn’t exist” argument. Climate concerns persistent trends in weather. If it were not a valid concept, then agriculture would not be possible. What you are engaged in is pure sophistry and spin. Climate exists and we are changing it.

    Comment by Ray Ladbury — 4 May 2007 @ 9:19 AM

  152. Re 145 and 150

    Climate has two meanings. It can mean a set of statistics when applied to new York, say. In other words you can talk about the climate of New York, and that is a set of averages of temperature, humidity, atmospheric pressure and precipitation.

    But there is also a climate system which consists of winds, sources and sinks of water vapour, ocean currents and effects from mountains and rivers. It also includes El Ninos, hurricanes, and droughts. When we talk about climate change, we should really be using the term climate system change. Although it is too late to alter that now, people should be aware that word ‘climate’ has two distinct meanings.

    Comment by Alastair McDonald — 4 May 2007 @ 10:23 AM

  153. re 141 (James): a minor but fun point: we’ll all burn up in the Sun’s Red Giant stage long before it becomes a White Dwarf. Now there will be a global warming with unanimous consensus!

    Comment by Rod B. — 4 May 2007 @ 10:32 AM

  154. Re 153.
    Rod B. wrote: “re 141 (James): a minor but fun point: we’ll all burn up in the Sun’s Red Giant stage long before it becomes a White Dwarf. Now there will be a global warming with unanimous consensus! ”
    Actually, I think Lindzen will be holding out to the evaporation of his last carbon atom–at least as long as there’s a microphone nearby.

    Comment by Ray Ladbury — 4 May 2007 @ 10:58 AM

  155. Well, I thought we’d beaten the horse until it was thoroughly dead. But it rears its ugly head…

    Re: #140 (Rod B.)

    But, and I hate to break it to you, if the temperature drops, IT’S COOLING!

    Suppose you win the lottery, and in one day your net worth increases from, say, $50,000 to $20,000,000. Over the next ten years, you invest 5 million in a fly-by-night company which goes bankrupt, donate 5 million to Oprah’s campaign to help children in Africa, and lose $9,949,999 gambling in Las Vegas. You’re left with $50,001.

    You complain about it to a friend, but he consoles you by saying, “Your net worth is more than what it was when you started — You’ve been getting richer for ten years!”

    Re: #146 (Caz)

    Using your criteria we haven’t had 3 decades of warming then. we’ve just had some warming – some cooling – some more warming and according to HadCrut (and RSS and UAH satellite) a more or less flat trend in the last decade.

    You haven’t run the numbers, have you?

    Nobody disputes that there’s natural variation in temperature. That’s what all the wiggles are about in the temperature graph. But those wiggles represent random fluctuations. It’s like flipping a coin and counting how many “heads” turn up for each ten flips. We expect 5 out of every 10, but that’s not what we observe. We see ups and downs, more or less — but over the long haul, it averages to 5 out of 10 (unless the coin is rigged).

    If we want to know which wiggles/changes are genuine trends rather than random fluctuation, we apply statistics.

    When we do so to the temperature time series, the theory “cooling from 1940 to 1970″ doesn’t even pass the most basic significance testing. And there’s plenty of data during such a long time period, so we can rule that out. The hypothesis “cooling from 1944 to 1951, followed by stasis from 1951 to 1975″ gives a strongly significant result. In fact, of all the hypotheses I’m aware of, this one gives the most significant result.

    For the last three decades, the statistically strongest hypothesis is “continuous warming,” while your “some warming – some cooling – some more warming and a more or less flat trend in the last decade” theory does not pass muster. Not even close.

    As a matter of fact, if you take only the data from 2000 to the present, you still get a statistically significant warming. The same is true for 1999 to the present, or 1998 to the present, or 1997 to the present, or … you get the idea.

    One last note: the latest corrections to the RSS and UAH satellite temperature data bring them into agreement with the surface temperature record and the computer model results for the lower troposphere. So, you’re wrong on all counts.

    Re: #141 (P. Lewis)

    If the temperature is warmer in 1969 than it was in 1939, we kinda think …

    Exactly. Both arguments are equally invalid — and this is a nice illustration of why.

    and: #150 (Ray Ladbury)

    It is a very different thing to say that 1970 was cooler than 1944 than it is to say there was a 30 year cooling trend.

    And that’s my point. For years now, we’ve been allowing this misrepresentation to persist. Let’s stop doing that.

    Comment by tamino — 4 May 2007 @ 11:10 AM

  156. Actually, the discussion between Rod and Tamino about whether cooling and flat trending constitutes cooling over the period reminds me a little of the Monty Python logician’s routine from the album of Monty Python and the Holy Grail. It takes place just after Sir Bedevere proves a woman is a witch by showing she weighs the same as a duck. It is not long, so I produce it here in all its glory:

    The sketch:

    Good evening. The last scene was interesting from the point of view of a professional logician because it contained a number of logical fallacies; that is, invalid propositional constructions and syllogistic forms, of the type so often committed by my wife.
    ‘All wood burns,’ states Sir Bedevere. ‘Therefore,’ he concludes, ‘all that burns is wood.’ This is, of course, pure bullshit. Universal affirmatives can only be partially converted: all of Alma Cogan is dead, but only some of the class of dead people are Alma Cogan. ‘Oh yes,’ one would think. However, my wife does not understand this necessary limitation of the conversion of a proposition; consequently, she does not understand me, for how can a woman expect to appreciate a professor of logic, if the simplest cloth-eared syllogism causes her to flounder?

    For example, given the premise, ‘all fish live underwater’ and ‘all mackerel are fish’, my wife will conclude, not that ‘all mackerel live underwater’, but that ‘if she buys kippers it will not rain’, or that ‘trout live in trees’, or even that ‘I do not love her any more.’ This she calls ‘using her intuition’. I call it ‘crap’, and it gets me very irritated because it is not logical. ‘There will be no supper tonight,’ she will sometimes cry upon my return home. ‘Why not?’ I will ask. ‘Because I have been screwing the milkman all day,’ she will say, quite oblivious of the howling error she has made. ‘But,’ I will wearily point out, ‘even given that the activities of screwing the milkman and getting supper are mutually exclusive, now that the screwing is over, surely then, supper may now, logically, be got.’ ‘You don’t love me any more,’ she will now often postulate. ‘If you did, you would give me one now and again, so that I would not have to rely on that rancid Pakistani for my orgasms.’ ‘I will give you one after you have got me my supper,’ I now usually scream, ‘but not before’– as you understand, making her bang contingent on the arrival of my supper. ‘God, you turn me on when you’re angry, you ancient brute!’ she now mysteriously deduces, forcing her sweetly throbbing tongue down my throat. ‘Fuck supper!’ I now invariably conclude, throwing logic somewhat joyously to the four winds, and so we thrash about on our milk-stained floor, transported by animal passion, until we sink back, exhausted, onto the cartons of yogurt.

    I’m afraid I seem to have strayed somewhat from my original brief. But in a nutshell: sex is more fun than logic– one cannot prove this, but it ‘is’ in the same sense that Mount Everest ‘is’, or that Alma Cogan ‘isn’t’.

    Goodnight.

    Comment by Ray Ladbury — 4 May 2007 @ 11:11 AM

  157. Re #143: [The difference in timescales between the exhaustion of fissionable materials on Earth and of the sun is many orders of magnitude, so your comparison is somewhat absurd…]

    We have a civilization that has existed for maybe 10^4 years, facing a problem that might doom it in 10^2 years if it doesn’t do something in the next 10^1 years. On that scale, worrying about the Earth running out of fissionables in 10^5 years, or the sun running out of hydrogen in 10^9 years seems equally absurd.

    [Where did I say I wanted to study the problem for another decade or two?]

    Back in #133: “We need to determine which of them, in what mix, will give the best results, in relation to climate change, and whatever other advantages and drawbacks they have.” That certainly implies a considerable period spent studying the various technologies to determine which is best, doesn’t it? Not to mention the indefinite time needed for some government (or worse, intergovernmental) commission to define “best” for us. And then we can wait for the National Energy Service to get around to installing the selected alternatives for us – after of course setting up a Civil Service exam procedure for prospective installers, hiring several layers of administrators, waiting through the court challenges…

    You can do all this, or you can just start taxing CO2 emission at (per the news this morning) $20 or so per ton, and let people decide how best to deal with the increased cost.

    [We need swift inter-governmental agreements on emissions targets…]

    Yes, and we need cold fusion, anti-gravity, and universal brotherhood. I expect to see at least one of those before any practical agreement of that sort.

    Comment by James — 4 May 2007 @ 12:36 PM

  158. re P. Lewis (148) I agree 100%! I was specifically chiding tamino ’cause he just took his mostly valid point to the ridiculous zealous extreme and said there was “no cooling” specifically between 1940 and 1970.

    Comment by Rod B. — 4 May 2007 @ 1:08 PM

  159. re P. Lewis (148) As an aside, with your background in the steelworks of Wales (or other places, e.g. Pittsburg, for others) you’re probably aware that the aerosols responsible for the cooling starting in 1940 were belching out in tons long before… Just a thought.

    Comment by Rod B. — 4 May 2007 @ 1:14 PM

  160. Rod B. said, “you’re probably aware that the aerosols responsible for the cooling starting in 1940 were belching out in tons long before… Just a thought.”
    Yes, and it is a reason why England was synomymous with “fog”–which wasn’t fog at all, but smog. And it did have a local effect. There’s a reason why those “dark Satanic mills” were dark. What you seemingly fail to appreciate is that energy consumption, like population tends to rise geometrically, so we were spewing a whole helluva lot more soot into the air in 1940 than in, say, 1910. This trend continued until we actually did something about it–passing clean air legislation, which happened around the same time in the US and Europe. It is not just the presence of particulates, but their amount, and unlike CO2, particulates do not accumulate, since they have a short lifetime.

    Comment by Ray Ladbury — 4 May 2007 @ 1:40 PM

  161. Re: 155

    One last note: the latest corrections to the RSS and UAH satellite temperature data bring them into agreement with the surface temperature record and the computer model results for the lower troposphere. So, you’re wrong on all counts

    Which surface temperature record are you talking about. GISS? HadCrut?
    The surface temp records have been diverging over the past decade so much so that there has been a study to try and identify the reasons.

    Even after corrections, the 30 year trends for RSS and UAH differ so I’m not sure how they both agree with the surface record. It is true, though that over the past decade RSS, UAH and HadCrut have a very similar – more or less flat trend.

    You chose a period between 1940 and 1970 to show a NON-significant trend and hence conclude there was no 30 year cooling. We could just as easily find period of NON-significant warming (or cooling) and hence conclude there is 30 year warming.

    PS if you want an argument about stats – we’ll take it elsewhere e.g. your site.

    Comment by Caz — 5 May 2007 @ 6:59 AM

  162. Re #155 — Tamino, no one disputes that your statistical analysis is accurate. It’s just that the phrase “global cooling” has been applied to the period from 1940 to 1970 when the slope of the rate of temperature increase changed. You’re probably right that we shouldn’t call it “cooling,” but it is a distinct period on the graph and we need to call it something.

    Comment by Barton Paul Levenson — 5 May 2007 @ 7:02 AM

  163. Gavin,

    I read the planetary energy imbalance thread you referred me to in #150. It also didn’t answer my question (it wasn’t even in the right neighborhood).

    To make the question clearer, has anyone ever assumed average emissions of all sorts, average solar output, average everything, for the various periods between 1900 and some recent date, and used those values to “predict” the climate in 2000 the same way the IPCC has used average values to predict climate change between the current date and 2100 using the same models?

    (And so you know where I stand, I concede that if we can find, and can afford to burn, the fossil fuels to produce the CO2 levels in the IPCC report, we’re in big trouble, but I don’t believe that is economically feasible. I think we’ll wind up in a fairly nasty economic mess long before the climate gets completely trashed. Rising demand and declining reserves don’t bode well for anyone — climatologists included — who assume oil will continue to be plentiful and cheap.)

    [Response: I don’t follow you. The simulations in the post I pointed you to were exactly what you describe – you start in the 19th century and with the observed changes in forcings of CO2, CH4, solar, volcanoes etc. you run forward until 2000 and you get the current temperature anomaly. The hindcasts have been done with all the models as part of the IPCC AR4 process. If this isn’t what you mean, let me know. -gavin]

    Comment by FurryCatHerder — 5 May 2007 @ 8:20 AM

  164. Gavin,

    The things I’ve seen in the various reports and papers I’ve read over the years, particularly the graphs (as I recall — I’m walking out the door at the moment, so I can’t go back and check) that were included in the thread you referenced, show the actual consumptions, events (volcanic erruptions, etc.) and so forth.

    The models included in the IPCC report are all, obviously, predictions based on assumed amounts of consumption, etc. What I’m looking for is a paper which describes how the models behave if the events of the 20th century were “predicted” based on average consumptions, emissions, volcanic events, solar output, etc.

    In other words, if the average activity is fed into those models as averages, rather than as actual data, how well do the models hold up? If instead of an actual Mount Pinatubo there is an “averaged out” mount Pinatubo (et cetera), do the models over predict or under predict climate change? If instead of actual fossil fuel use, with all the ups and downs of wars and depressions, there is an averaged out fossil fuel use, do the models over predict or under predict climate change?

    [Response: Ahh… That’s a little clearer. First off, people only do 20th Century simulations in order to match observations, and so everyone uses the actual forcings, not forcings that would have been estimated in 1900 if anyone had thought to do that. Therefore I don’t think that exactly that you want exists. However, the closest to what you want is probably the early Hansen simulations (published in 1989) and which contained estimates for the forcings into the future and ended up with temperature changes that were pretty close to what happened. They even used a hypothesised volcano in 1995. -gavin]

    Comment by FurryCatHerder — 5 May 2007 @ 10:08 AM

  165. Re: #161 (Caz)

    It is true, though that over the past decade RSS, UAH and HadCrut have a very similar – more or less flat trend.

    If we analyze GISS data using linear regression, we get the following temperature change rates:

    GISS GLB_TSST:
    From 1995 To 2007 2.2 +/- 1.1
    From 1996 To 2007 2.4 +/- 1.3
    From 1997 To 2007 2.1 +/- 1.5
    From 1998 To 2007 2.1 +/- 1.9
    From 1999 To 2007 3.6 +/- 1.7
    From 2000 To 2007 3.1 +/- 2.1

    Every one of those time intervals gives a statistically significant rate of increase. If we do the same using HADCRUT3, we get:

    HADCRUT3:
    From 1995 To 2007 1.9 +/- 1.5
    From 1996 To 2007 2.0 +/- 1.8
    From 1997 To 2007 0.9 +/- 1.7
    From 1998 To 2007 0.7 +/- 1.9
    From 1999 To 2007 2.3 +/- 1.5
    From 2000 To 2007 2.0 +/- 1.8

    Only the time frames 1997-2007 and 1998-2007 fail to give a significant response to linear regression. But the time frame 1999-2007 (and 2000-2007) does give a significant result. That’s a clue: there is indeed a trend in the last decade, but it’s not linear. If we do higher-order polynomial regressions, or Fourier fits, we do get statistically significant response for the time frame 1997-2007 (as well as 1998-2007). So there is most definitely a trend there, even in HadCRU data; your “more or less flat” claim doesn’t hold water.

    The main reason for the difference in GISS and HadCRU results is that the HadCRU data show a much larger response to the el Nino of 1998. The statistically strongest model for the last decade is: big rise due to el Nino, big fall due to subsiding of el Nino, warming 1999 to the present.

    When we look at the time frame 1940 to 1970 (HadCRU or GISS), again there’s no statistically significant response to linear regression. But again, applying higher-order polynomial regression or Fourier fitting does give a statistically significant response. That’s why I don’t claim there’s no trend from 1940 to 1970; I’ve pointed out all along that there was a notable cooling from about 1944 to about 1951. But I do state that the trend is not linear, and it’s certainly not correct to characterize that time period as “three decades of cooling.”

    PS if you want an argument about stats – we’ll take it elsewhere e.g. your site.

    I’m not the least bit interested in arguing stats with you, here or anywhere else. Not only have we beaten the horse thoroughly dead, you seem to want to beat its ghost as well. I’m done.

    Comment by tamino — 5 May 2007 @ 2:32 PM

  166. Re 162. Words are important when you get to politics. To call the ’40-’70 period global cooling is inaccurate and it makes it sound as if global warming is a new thing that came on the scene in 1975 and hence less certain.
    The medical procedure known as “IDX” or intact dilation and extraction was dead as soon as abortion opponents stuck the name “partial birth abortion”–a medically meaningless description.
    We need to be aware of our lexicon. Global warming sounds like a good idea to folks north of the Mason-Dixon Line from December to March. And Global cooling makes it sound as if scientists can’t make up their mind. I would recommend sticking to the more accurate “climate change” and perhaps calling the ’40-’70 period a “hiatus” in the overall warming trend due to aerosol pollution.

    Comment by ray ladbury — 5 May 2007 @ 3:45 PM

  167. Re #161/165: Caz, you picked a fight over stats with someone who is rather more qualified at time series analysis than any of the “objectivists” over at ClimateAudit, and look what happened.

    As Gavin has pointed out here in the past, the argument that there has been no little or no warming over the last ten years depends on disingenuously starting an analysis at a record year and stopping before the next one. (This transparent disingenuousness is why Tamino is uninterested in arguing with you further, BTW.) We have yet to hit an unambiguous new reord year post-1998, but if one looks back over the record of the last thirty years or so it’s possible to identify several multi-year periods of “cooling” in between new record years. As the warming proceeds unevenly, that will always be true. Of course, when we do hit that next clearly warmer year (and this year is a possibility), I’m sure the “auditors” will come up with some other lame argument.

    Comment by Steve Bloom — 5 May 2007 @ 6:10 PM

  168. I am going to jump into this “global cooling” issue. I want nothing to do with cherry picked data showing a cooling since 1999 or whatever. But I do not think the 1940-1970 cooling should be dismissed as random fluctuations. Globally the cooling was small, but the further north you go the more significant it gets. For example, see figure 2.6 of the Arctic Climate Impact Assessment where the trend is clear and greater than one degree C. Looking at figure 1a of this Johannssen et. al. paper we see both the early 20th century warming and subsequent cooling was regional, centered on the Arctic, rather than truly global. They argue that the warming/cooling was caused by “natural variability of the climate system”, but argue the more recent warming has a much more global distribution and must be primarily anthropogenic.

    I am not at all supporting a global warming is natural argument, just pointing out that significant events should not be dismissed as random.

    Comment by Blair Dowden — 5 May 2007 @ 7:03 PM

  169. Re 136:

    I would assume that solar irradiance is in terms of the W/m2 on a plane normal to the rays of the sun. In contrast, the average change in insolation at the top of the atmosphere is the change in solar irradiance divided by 4 (Because a sphere’s surface has 4 times the area as it’s cross section). Then, you have to muliply by (1-albedo)=~ 0.7 to get the solar radiative forcing, the change in absorbed solar radiation. So solar radiative forcing of climate on Earth will typically be around 0.175 times the change in solar irradiance.

    Comment by Pat — 6 May 2007 @ 9:48 PM

  170. “I am not at all supporting a global warming is natural argument, just pointing out that significant events should not be dismissed as random.”

    Yes, some random tornadoes came by today, it must be a trend.

    You don’t have to apologize, Blair, your FUD is clear.

    Comment by Thomas Lee Elifritz — 6 May 2007 @ 10:18 PM

  171. Re # 126, 134, 146; It seems to be highly reasonable to make clear time period distinctions within the cooling phase from 1940 to about the 1970s. But the cooling period started very precisely in winter 1939/40, particularly in Northern Europe which experienced suddenly the coldest winter for 110 years, although the late 1930s had been the warmest years for presumably 200 years, and the autumns the warmest for almost 500 years. Material to this question can be found on the reference link Re #2 above, or on http://www.1ocean-1climate.com which displays an interesting front page story.

    Comment by L.R. — 7 May 2007 @ 5:19 AM

  172. Re #170: Thomas, do you actually read beyond the first sentence? I explained that the apparent 1940-1970 cooling was really a recovery from the earlier warming, which was a regional event. This takes nothing away from the fact the recent warming is anthropogenic. Reality is complex and sometimes uncertain. The fear and doubt are in your own mind.

    Maybe L.R. in #171 should re-read what I said, and check my references. He will find a real explanation for the apparent cooling, far different than the rubbish he referenced.

    Comment by Blair Dowden — 7 May 2007 @ 6:24 AM

  173. Blair, You are talking about an event on a large but still local scale–not a global scale. No one is arguing that the period from 1940-1975 was not in some way anomalous. There is even a fair agreement that part of it was caused by aerosols, and part by ocean currents (in the North). The important points, however are:
    1)The cooling trend was not global.
    2)To say that some years saw cooling in the period from 1940-1975 is a very different thing than saying 1940-1975 was a period of cooling.
    3)The term “global cooling” is inaccurate and is used with relish by denialists.
    No one is saying that cooling did not occur during the period–from 1940-1950–and then a flat trend from about 1950-1975. Moreover, the amount of cooling seen depends on the dataset–quite unlike the warming we are seeing now. That right there tells you that what you were seeing was not global.

    Comment by Ray Ladbury — 7 May 2007 @ 6:30 AM

  174. Re #157 “Back in #133: “We need to determine which of them, in what mix, will give the best results, in relation to climate change, and whatever other advantages and drawbacks they have.” That certainly implies a considerable period spent studying the various technologies to determine which is best, doesn’t it?”

    No, it doesn’t, if you mean 20 years plus, as you said previously. In the short term, it’s clear enough how to get started: energy efficiency, demand reduction (mainly in rich countries), plus carbon capture and sequestration from coal-fired power stations for China and India, where the choice for coal has already been made and would be very hard to reverse. For low C02 producing electricity generation in rich countries, I’d say key decisions at government level could be taken fairy quickly (months to a couple of years) once the commitment to reduce GHG emissions (see below) is made. Different options require different infrastructure and R&D investments, institutional frameworks and political coalitions, which is why a shoulder-shrugging “leave it to the market” is so hopeless: which options win out in “the market” will be determined by decisions on infrastructure and institutions and if no such decisions are made, none of them will develop fast enough.

    “You can do all this, or you can just start taxing CO2 emission at (per the news this morning) $20 or so per ton, and let people decide how best to deal with the increased cost.

    [We need swift inter-governmental agreements on emissions targets…]”

    Without inter-governmental agreement (which doesn’t need to involve more than the G8 + China and India at most, and fewer would almost certainly do), it’s very unlikely serious emissions taxes or rationing will be introduced, because big business won’t stand for being disadvantaged relative to foreign competitors.

    Comment by Nick Gotts — 7 May 2007 @ 6:37 AM

  175. “L.R.” and earlier “arnd” — we keep seeing people pop in and drop links to one or more of these enthusiast’s pages (Naval War thesis; warchangesclimate.com; bernaerts-sealaw.com; 1ocean-1system.de; oceanclimate.de; seaclimate.com; and now 1ocean-1climate.com). I may have missed a few pages or userids; often the userids are also links to the same websites. It may be boosting Google pagerank by having links from RC to there.

    Asserting “global cooling from naval war” in the absence of science, math, and temperature data isn’t convincing; the approaches here at RC make sense because they do more than assert their ideas.

    Comment by Hank Roberts — 7 May 2007 @ 8:47 AM

  176. Re #174: There certainly seem to be some gaps in that. For instance, you’d have “…carbon capture and sequestration from coal-fired power stations for China and India…” when no one knows whether this technology will actually work, let alone how to do it economically. Suppose it turns out not to be viable? Then you’ve committed public money, rather than the fortunes of greedy capitalists, to building these coal plants.

    Similarly with energy efficiency & demand reduction: how do you do that effectively without some market incentive? Send squads of eco-cops around to change out everyone’s incandescent light bulbs?

    […it’s very unlikely serious emissions taxes or rationing will be introduced, because big business won’t stand for being disadvantaged relative to
    foreign competitors.]

    Why should it disadvantage “big business”, particularly? Understand that I’m not suggesting tax increases, but tax shifting. Instead of collecting X dollars in sales tax or VAT, it would collect the same amount from a CO2 tax. (Which could be applied to imports as well.) Neither business not the consumer would be at any particular overall disadvantage, and they’d have the opportunity to gain advantage by reducing energy use. Of course in the long run the least efficient would be at a disadvantage, but this is always the case. Instead of denying the market, you target it to produce the results you want.

    Comment by James — 7 May 2007 @ 11:27 AM

  177. Re #173: Ray, we are arguing over semantics here. First, I think the significant event in question is the warming in the early 20th century. Although the warming was felt globally, it was concentrated in the Arctic, far more than the with global warming that is occurring today. So there was a regional warming, with “natural” (ie. we don’t know what) causes, and possibly a separately caused (solar?) global warming as well.

    When the regional event stopped, the consequence was regional cooling, but enough of it that it was felt globally. So is it correct to say there was 30 years of global cooling? It depends on what kind of averaging is used. You can get 30 years of gradual cooling, or shorter periods of more rapid cooling. I realize that out of the context I just described talking about global cooling is misleading, and yes, useful for denialists.

    The main point I want to get across is there was no real cooling “event”, but rather the cessation of a prior warming event. But the global cooling did occur.

    Comment by Blair Dowden — 7 May 2007 @ 12:13 PM

  178. Blair, the reason I am arguing semantics is because our opponents sieze on semantics any chance they get. Thus, while there was cooling in this period, it wasn’t globing, it wasn’t sustained. So why do we persist in handing them an issue that just confuses the public?

    Comment by Ray Ladbury — 7 May 2007 @ 1:24 PM

  179. re Ray (173): I’ll admit I’m not intimately familiar with all of the data measurements and their processing, but it seems grossly suspicious to say late 1800s to 1940 and 1975 to present were good global measurements, but that 1940-1970 cooling thing — well that was just a regional anamoly. How convenient.

    Comment by Rod B — 7 May 2007 @ 3:50 PM

  180. Re: Rod B (179) 1940-1970: I thought all this as talked about earlier (under dimming, which ha been regional), but NASA GISS has a nice short reference:

    http://www.giss.nasa.gov/meetings/pollution2002/d2_baltensperger.html

    They see a big spike in sulfates in Alpine ice cores, going back down around 1975-1980, a similar pronounced spike in Arctic (Greenland), and nothing in Antarctica. It is quite plausible that this is related to the rapid, dirty industrialization that started ~ WW II, of which the most concentrated effects were in parts of N. America and Europe, and which certainly continued, and which certainly had visible local effects [I grew up near Pittsburgh, PA … and they were certainly visible, as long as there was a steel business there.]

    Another paper analyzes Himalayan ice-core records:
    www-bprc.mps.ohio-state.edu/Icecore/Abstracts/Duan%20et%20al%20GRL%202007.pdf
    This shows South Asian sulfates rising, at same time as N. American/European ones have been dropping (Clean Air Acts).

    I’ve lost track of the reference, but I did see a modeling study that showed that by accepting really awful acid rain, one could locally hold back warming for a decade or two in several regional areas… China may be trying…

    Comment by John Mashey — 7 May 2007 @ 6:00 PM

  181. Re #178: Ray, now we have a difference in philosophy. I want to understand every aspect of climate, and do not want to be restricted because it might be misused to “fool the public”. Denialists will find a way to fool the public anyway. Some of the sources of climate change are non-anthropogenic, such as a good part of the early 20th century warming. As greenhouse gas levels rise, non-anthropogenic forcings become less significant.

    Re #180: John, I do not think that aerosols had much to do with the 1940-1970 cooling (that word again) because there is no need for a negative forcing to explain what happened after the end of the prior warming event. Aerosols did not positively contribute to the early 20th century northern hemisphere warming, and greenhouse gas levels were insufficient at the time. We can detect a rise in aerosols, but have little idea of the magnitude. Even today, the current estimate on direct aerosol forcing (from IPCC 2007) is 0.1 to 0.9 watts per square meter. I don’t know what they use for an aerosol forcing in 20th century climate models, but I suspect it is largely guesswork.

    Comment by Blair Dowden — 7 May 2007 @ 8:28 PM

  182. Re #176 “There certainly seem to be some gaps in that. For instance, you’d have “…carbon capture and sequestration from coal-fired power stations for China and India…” when no one knows whether this technology will actually work, let alone how to do it economically.”

    Well, CO2 capture from power station exhaust gases has been done for over 60 years by amine scrubbing (in cases where the gas is wanted). Sequestration of CO2 from natural gas fields is already being done in the North Sea and Algeria. The IPCC says it will work in the sense that little of the gas will escape within 1000 years (I’m relying here on referenced information in George Monbiot’s “Heat”). It had better work (and be retro-fittable, which is tougher), given that China is building one new coal-fired power station a week and isn’t about to stop. This is one place where international agreement is clearly needed, and technical research is also needed urgently, whether “the market” says so or not.

    “Similarly with energy efficiency & demand reduction: how do you do that effectively without some market incentive? Send squads of eco-cops around to change out everyone’s incandescent light bulbs?”
    Banning the sale (not use) of incandescent bulbs, and other energy-inefficient technologies, is worth considering – in the case of bulbs, it is already done in Australia. But I’m not arguing against the use of market incentives for energy users, which I favour; I’m arguing against leaving major R&D and production decisions in the energy sector to market forces, which is what you are proposing.

    “Why should it [CO2 tax] disadvantage “big business”, particularly?”
    The point is not that it would disadvantage big business particularly, but that it’s big business that has the influence to stop it.

    “Understand that I’m not suggesting tax increases, but tax shifting. Instead of collecting X dollars in sales tax or VAT, it would collect the same amount from a CO2 tax. (Which could be applied to imports as well.)”
    The basic idea of tax shifting is fine, and in principle applying the CO2 tax to imports should avoid home corporations’ objections, but unless foreign governments have at least agreed to support the measure, how is the home government going to know how much CO2 was generated in the manufacture of imports?

    Comment by Nick Gotts — 8 May 2007 @ 5:26 AM

  183. Blair, I am not arguing against understanding the period between 1940-75. I’m saying that we need to be careful and accurate in describing it. It was not 3 decades of cooling. It was a few years of cooling after a warming event, followed by 2 decades of relatively stable temperatures. Under that description, it is no less interesting to understand, and it doesn’t give the impression to people (nor the opportunity to denialists) that climate is cyclic–which it is not. Scientists need to be as careful with their language as they are with their math.

    Comment by Ray Ladbury — 8 May 2007 @ 7:17 AM

  184. Rod B. No. Not convenient. Accurate. If you are looking at a truly global change, then the trend should be robust across data sets and across analysis techniques. The warming trend is, while the cooling trend is not. No one is questioning whether the trend from about 1944-1950 showed cooling in the Northern Hemisphere, nor that the subsequent 20-25 years showed flat trending. That is interesting and is and should be studied. But the cooling was not global, though the flat trend was (and hence is more interesting). Stop looking for conspiracies where there are none.

    Comment by Ray Ladbury — 8 May 2007 @ 7:22 AM

  185. The verious contributions about global cooling ca. 1940-1970 and reference gave me a lot information, particulary concering the arctic winters in Northern Europe starting with winter 1939/40, with subsequent cooling in a wider region, which seems to be still unexplained. At least no one touched the question, or only indirectly e.g. #172, #175. It was not CO2, and presumably it did not came out of the blue. Or?

    Comment by Burt V. — 8 May 2007 @ 12:10 PM

  186. Burt, the “naval war causes cooling” people regularly drop links in many climate forums. They say oil spills coincided with warming during the world wars, and infer causation, but I looked for quantities and found that, back in those decades, natural seepage of petroleum far outweighed the tonnage of shipping sunk.

    Even today natural seepage is perhaps half the oil spilled, the rest being from shipping. So yes, petroleum spilled in the water has perhaps doubled from the natural baseline seepage. Nobody that I know of has a theory for why that would change the planet’s radiative balance. If it calms the waves and makes them better mirrors it ought to increase reflection. If it’s a source for CO2 by the petroleum breaking down, it’s still a small one compared to the burning of the fossil fuel that survives transportation.

    Papers modeling climate retrospectively show ocean currents and other known changes sufficient to explain that. Read the science suggested above, it will get you started. You won’t find the alternative explanations on the pages run by the enthusiasts for a single cause for everything.

    Do some searches, you’ll find the information.

    Comment by Hank Roberts — 8 May 2007 @ 12:48 PM

  187. Ray, not conspiracies, but it sure looks deliberately obtuse. All those late 1800s to 2000+ temp vs. CO2 graphs simply trumpet “global”. Now you might be right about the roughly 1940-1970 “cooling” period being exclusively something less than global (though, why, is perplexing….) but it sure makes for a hard-to-explain ugly baby. Within scientific circles I see no need or benefit to be so devious (though ironically I can understand it in non-scientific discourse.)

    Comment by Rod B — 8 May 2007 @ 3:35 PM

  188. If anybody is interested, I have proposed the term ‘Neocene’ for the new geological era that is presently (and demonstrably I might add) upon us.

    I did enough research that I am confident it will stick :

    http://cosmic.lifeform.org/?p=292

    Comment by Thomas Lee Elifritz — 8 May 2007 @ 3:36 PM

  189. Re #188 I think you are a bit late with that suggestion for the geological era that started very recently. Nobel Prize winner Paul Crutzen has already suggested ‘Anthropocene’ which has been widely accepted. There is even an ‘Early Anthropocene’ period. See http://geology.about.com/od/geotime_dating/a/anthropocene.htm for a link to Paul’s proposal published in Nature, and Wikipedia for details of the Early Anthropocene http://en.wikipedia.org/wiki/Early_anthropocene

    Comment by Alastair McDonald — 8 May 2007 @ 4:38 PM

  190. Re #188: The term “Anthropocene” has already been suggested to follow the Holocene.

    Comment by Blair Dowden — 8 May 2007 @ 4:39 PM

  191. I think it’s a bit confusing there; you have an image copy:

    http://www.lifeform.org/files/Neocene_New_Geological_Era.png

    That’s a clickable link to the home page for globalwarmingart.com.

    Below that you have:

    Welcome to the Neocene – A New Geological Era
    http://www.globalwarmingart.com

    People may mistakenly think you got the text with the image at globalwarmingart.com; it might be clearer to just link to his image and separate your text (else the text and the filename are confusing about attribution).

    But I suspect the next era may be named by some AI, perhaps as the “post-Anthropocene” if we don’t get smarter about this stuff.

    Comment by Hank Roberts — 8 May 2007 @ 5:28 PM

  192. Anthropocene? Not a chance. Things are now beyond our control.

    If we do manage to get things under control, then that term might be appropriate, but barring some sort of crash international space program, the chances of that happening now are slim to none. Physics doesn’t lie, it just gets more accurate over time. The result now is crystal clear.

    I’ve passed the testing stage, and have achieved acceptance. I couldn’t care less anymore. Humans no longer deserve this planet. It will shortly be taken away from them. For a little insight into what is to come, I suggest that everyone take a good hard look at Betty Ann Luca’s Pheonix experience.

    When you are living on a spaceship, the very first thing you need to get under control are carbon dioxide and thermal management. It will kill you quicker even than dying of thirst or hunger. We have completely and utterly failed the very first test of intelligence in the universe.

    Comment by Thomas Lee Elifritz — 8 May 2007 @ 7:56 PM

  193. There is nothing in the name anthropocene which means that man is in control, only that they are the cause, and since new epochs tend to be marked by extinctions, then it implies that man is responsible for the current extinction.

    Of course larger extinctions mark the beginning of new ‘periods’, still larger extinctions herald in ‘eras’, and the largest geological divisions are called ‘eons’. The last two eons were the Proterozoic (early life) and Phanerozoic (visible life). For the next eon beginning now I propose the name Anozoic (No life) or perhaps Necronozoic (dead life.)

    Comment by Alastair McDonald — 9 May 2007 @ 5:07 AM

  194. [[Humans no longer deserve this planet. It will shortly be taken away from them. For a little insight into what is to come, I suggest that everyone take a good hard look at Betty Ann Luca’s Pheonix experience.]]

    And don’t forget the Urantia Book, Roswell, and Harmonic Convergence.

    Comment by Barton Paul Levenson — 9 May 2007 @ 5:46 AM

  195. Rod B., Look, no one is trying to hide anything about the 1940-1975 period, but the very fact that one can look at the different graphs and they show the effect to greater degrees or lesser and the fact that one can have different interpretations of the graph shows we are not dealing with a robust, global effect. And Tamino is 100% right. Other than the short period from 1944 to 1950, there is no consistent trend, cooling or warming in the data. If you look at the period just prior to 1944, the warming was anomalously high, so it is not surprising that this would be followed by some cooling. If we look closely at what was going on in this period, we might come to an understanding of the oscillation. Actually, I find the period from 1950-1975 even more interesting–precisely because of the relative stasis.
    It is certainly not spin or deviousness to insist on precision, and to say the period from 1944-1975 was one of cooling is imprecise at best and misleading (by some, deliberately so) at worst.

    Comment by Ray Ladbury — 9 May 2007 @ 7:20 AM

  196. And don’t forget the Urantia Book, Roswell, and Harmonic Convergence.

    AOL eh? Figures.

    Never met Betty Luca, have you.

    I challenge Mr. Crutzen’s term ‘Anthorpocene’, because that would imply that mankind take complete control of the environment, and return carbon dioxide concentration to ambient levels (say 300 to 320 ppm to ward off any further ice ages), establish a worldwide population commensurate with the carrying capacity of the Earth, and remediate the air, waters and lands of the planet, while preserving abundant wildlife areas, which may or may not happen. The Anthropocene, if it were to occur, would follow the Neocene, since humanity is demonstrably not in control of the Holocene, according to any established control theory. Hence, the Neocene.

    Should the Anthropocene era come to pass, it would reduce the Neocene era, which is demonstrably upon us, to a transient thermal event, an unfortunate but necessary experiment in planetary engineering. At that point one would expect humanity to be a space faring civilization, and then perhaps Ms. Luca may finally get the respect she deserves.

    The Neocene term is the result of research, and not an off the cuff, spur of the moment statement at a conference. The term has demonstrably fallen out of favor as representing the early Pliestocene, and is definitively available. Science is about alternatives, options and challenges. We have indeed also entered the fifth (Pentary) geological era, I might add.

    FWIW, I’ve also somewhat successfully challenged the IAU’s definition of planet. Now that terrestrial planets are in sight, we may soon have many hundreds and thousands of examples available for inspection, and then we may understand more fully the Earth’s place in the hierarchy of extrasolar planets, and the dogma, stigma and indeed hysteria, that surrounds the mere possibility of non-human life in the universe, may eventually fade. Humans may indeed have a place in this universe, but according to the empirical evidence thus far, it is now one of unremarkable and tragic obscurity.

    Comment by Thomas Lee Elifritz — 9 May 2007 @ 9:30 AM

  197. have you answered pete best’s question #108…couldn’t see it answered anywhere….

    Comment by Ruth Jarman — 9 May 2007 @ 11:17 AM

  198. Advice to Lord Monckton: buying ads in the WSJ claiming you challenge Mr. Gore to a debate is hubris.
    You don’t have any history of understanding the subject yet. Establish your importance by doing the work.

    Comment by Hank Roberts — 9 May 2007 @ 11:21 AM

  199. # 186; Complete agreement, Hank, whoever says oil spills coincided with warming during the world wars, is certainly wrong. It was unlikely seven decades ago, and is presumably even insignificant today. Until now I have not read all texts of the reference you mentioned, #175, but until now I have not found any text which makes such claim. It seems to me that the “enthusiast” claim something very different, namely the impact of a sudden seawater temperature change on atmospheric air temperature conditions. But I will continue to see whether they indeed link oil spills to cooling (not warming), I will inform you as soon as such claim is indeed made, or can you direct me to the text?

    Comment by Burt V. — 9 May 2007 @ 12:59 PM

  200. Burt, type “Adrianne” into the search box at top of page, that’ll find you many of the times this stuff was dropped here.
    Or use Google to find strings from this, it’s from one or more of those many web pages tied to his book and idea:

    All that stuff polluted the sea
    and was taken away by the Gulf Current
    or by the Norwegian Current
    up to the North. It was precisely there
    that the “big warming” occurred.

    Everyone’s entitled to their own ideas, but not to insist on attention from other people, nor to insist that scientists recognize them as clever, adopt them, and defend them. The sites are full of ideas. Depth charges used in attacking submarines mixed the layers of the ocean up —-somewhat, locally, briefly. Did that cause the warm water to sink below the cold water and not reappear for thirty years? I doubt it. Compare the energy and mixing there to the amount of mixing that occurs naturally? No numbers, no comparisons.

    I understand you want help understanding Bernaerts’s ideas. I don’t know where you’ll find someone to help you with that. Good luck.

    Comment by Hank Roberts — 9 May 2007 @ 3:43 PM

  201. I apologize if this subject has been covered elsewhere on this site, but when it comes to mitigation of AGW, I think people minimize the importance of agriculture. According to David R. Montgomery in his book Soil: The Erosion of Civilizations, “No-till agriculture has the potential to increase the organic matter contect of the top few inches of soil by about 1 percent a decade. [O]ver twenty to thirty years that can add up to about 10 tons of carbon per acre. … A third of the total carbon dioxide buildup in the atmosphere since the industrial revolution has come not from fossil fuels but from degradation of soil organic matter. … If every farmer in the United States were to adopt no-till practices and plant cover crops, American agriculture could squirrel away as much as 300 million tons of carbon in the soil each year.” Montgomery estimates the carbon sequestration potential of the world’s cropland at 25 percent of the current carbon emissions.

    I find this news encouraging, and yet… Farmers are now in a race to produce crops for biofuels, and in the usual American fashion, are further degrading the soil to do so. The production of crops specifically to burn in our vehicles may in fact ADD carbon to the atmosphere by bringing more land under cultivation. Solution: End ag-fuel subsidies and increase soil-conservation (no-till, organic) subsidies.

    http://www.amazon.com/Dirt-Civilizations-David-R-Montgomery/dp/0520248708/ref=sr_1_1/103-0239804-2543041?ie=UTF8&s=books&qid=1178761291&sr=1-1

    Comment by Nancy Rutman — 9 May 2007 @ 8:53 PM

  202. American agriculture could

    We need to bioengineer a carbon to compost cycle. Any specific suggestions? It takes energy. There is only so much land and sunlight available. Plus you need other nutrients. Clearly reducing emissions and soil conservation and enhancement practices are the key.

    Comment by Thomas Lee Elifritz — 9 May 2007 @ 9:35 PM

  203. Re Burt & Hank: Being an open forum, I feel that everyone is free to sustain their beliefs. As you can see, I am very into the Naval War theory, as it explains various climatic events, such as Spitsbergen Big Warming, ald other climatic trends. I don’t agree to the IPCC report because it has other focus parts, together with climate: political, financial, etc. This is why it has faults. If it had been just climate-oriented, I am sure that it would look alot different.

    I am interested in debating the global warming issue, because it is one of the biggest problems that we are facing and I think everybody should care. I have found Bernaerts’ thesis on the internet and I followed the links from there, I read more and more on it and I find it logical for me to understand. I accept the fact that others have other opinions, I can also accept that maybe my opinion is not good, but I would like to see arguments that contradict me, as I am always open to a constructive debate.

    Comment by Adrianne — 15 May 2007 @ 1:50 PM

  204. Gavin,
    The IPCC AR4 report has an FAQ aimed, I assume, at the educated reader who doesn’t necessarily have a science background.

    FAQ 10.3 says-
    “Stabilisation of CO2 emissions at current levels would result in a continuous increase of atmospheric CO2 over the 21st century and beyond,
    …snipped…
    In fact, only in the case of essentially complete elimination of emissions can the atmospheric concentration of CO2 ultimately be stabilised at a constant level.”

    Is this true, or just badly written?

    The bulk of the IPCC report seems based on models are extrapolating forward the trajectory of temperatures where CO2 emmissions are stabilised at varying concentrations, such as 450ppm.

    My mind is led (as is, I suspect, the public mind)to the idea that if we reduce use of fossil fuels (as fossil fuels contribute ~75% of the CO2), it is possible to reach a dynamic equilibrium at (say) 450ppm.

    And there it will stay. Things are a bit warmer, bit sea level rise, but oh well, that was a close call!

    BUT the wording in the FAQ seems to say that unless ALL emmissions of CO2 are eliminated – no oil burnt, no gas burnt, no coal burnt – then it is literally impossible to stablilise CO2 levels. Impossible.

    That is, I assume, the ocean CO2 ‘sump’ is full, the ‘modern’ carbon cycle is roughly in balance, the earth can absorb no further fossil carbon. It is sated. Couldn’t take another atom. Not a crumb. And therefore every fossil carbon atom emitted from ~now on has ‘nowhere to go’, and is in effect cumulative in the atmosphere. With no way back out for millions of years (when phytoplankton may ultimately remove CO2 as they die and are buried deep in ocean sediment).

    The uneasy feeling that yes, this is exactly what the reported words mean is reinforced when the FAQ goes on to say:

    “All other cases of moderate CO2 emission reductions show increasing concentrations because of the characteristic exchange processes associated with the cycling of carbon in the climate system.

    More specifically, the rate of emission of CO2 currently greatly exceeds its rate of removal, and the slow and incomplete removal implies that small to moderate reductions in its emissions would not result in stabilisation of CO2 concentrations, but rather would only reduce the rate of its growth in coming decades.”

    Are they really saying that CO2 will accumulate in the atmosphere in (broadly speaking) direct proportion to the rate at which fossil fuels are burnt?

    What is the ‘conversion’ between x tonnes of emitted carbon (in coal, oil, gas)and an increase of 1 ppm in the atmosphere?

    We roughly know the tonnage coal, oil, and gas likely to be recoverd. It is very likely is will all, over human existance on earth (i.e. beyond 2100), be burnt.

    Is it not possible to therefore estimate the ultimate level of permanent atmospheric CO2 ppm once all available fossil fuel is burnt?

    I have tried to think how all fossil fuel use could be agreed to be left in the ground. By all nations. For all time. It is utterly impossible.

    If it it true that even 450ppm can only be “attained” if NO MORE fossil fuels are burnt, why bother to model the temperature trajectory and sea level consequences of an atmosphere with CO2 “stabilised” at 450ppm?

    Why not simply model the ppm rise with burning of available fuels, and THEN model thousands of years hence to the point of a stable hot climate, less land, more sea, and with no ice on earth?

    Surely that would be the truth. The idea that CO2 levels can be stabilised at all, given the structure of our society and in what volume we depend on coal and oil, is little more than a convenient fiction.

    I sincerely hope I have utterly misunderstood the true meaning of the sections of the report quoted!

    Thank you for your work and time,
    Lorenzo

    Comment by Lorenzo — 24 May 2007 @ 4:36 AM

  205. [[What is the ‘conversion’ between x tonnes of emitted carbon (in coal, oil, gas)and an increase of 1 ppm in the atmosphere? ]]

    As I understand it, the sinks take up about half of human emissions. That’s about to change, though. There are signs the biggest sink — the upper ocean — is becoming saturated.

    Comment by Barton Paul Levenson — 25 May 2007 @ 6:45 AM

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