Chinese whispers in Australia

We decided months ago that we would not comment on leaks of the draft of the upcoming IPCC report (due Feb 2007) but we are prepared to correct obvious errors. The ongoing revisions of the text and the numerous drafts make any such commentary, let alone conclusions drawn from it, pretty pointless. This is even more true when the leaks are obviously confused about a central point. The principle error in the latest ‘exclusive’ is that the writer confuses a tightening of the estimate of climate sensitivity to 2xCO2 (as discussed here) with projections of climate change in 2100. These projections obviously depend on the uncertainties in the scenarios of future technology, economic progress and population (etc.) plus uncertainties in feedbacks related to the carbon or methane cycles. Unfortunately these have not been reduced since the last assessment report (and in some cases have actually increased).

That occasional stories will come out that get basic things wrong is unfortunate but not surprising. What is more troubling is that they subsequently get picked up by Reuters and UPI, and republished in places (such as Scientific American, though in their defence, it is simply a posting of the wire report) where the editors should know better. Worse still, the wire service stories are too brief to make the source of the error obvious, and thus the error gets propagated in an ever more confused state. As usual the blogsphere is playing a key role in amplifying and further muddying the story. The advantage of blogs is that errors can be corrected quickly, and the comments on Prometheus for instance, quickly revealed the confusion and the potential agenda of the original story.

There will be plenty of time to discuss the new IPCC report when it comes out and where everyone can read for themselves what has and what hasn’t changed since 2001. Until then, we would counsel against journalists and editors jumping at supposed ‘exclusives’ and – more dangerously – going ahead with them without even a basic sanity check of the details.

81 comments on this post.
  1. Eachran:

    Just a point for Gar or anyone else interested, we were talking about elasticities sometime ago.

    France has reported a drop in car use and in increase in public transport use since price increase of petrol/gas. I dont know what your French is like but the report is not difficult to understand.

    Les Français prennent moins leur voiture à cause du prix de l’essence

    Les Français ont moins pris leur voiture en 2005 qu’auparavant: pour la première fois depuis près de 30 ans, la circulation des véhicules particuliers a diminué sous l’effet de la hausse des carburants et du développement de l’offre de transports collectifs. Selon une étude du ministère des Transports publiée vendredi, la circulation des voitures particulières a baissé de 1,4% en 2005 en France, “pour la première fois depuis 1974, année du premier choc pétrolier”, lorsque les tensions géopolitiques au Proche-Orient avaient fait bondir les cours du pétrole. En 2005, l’automobile a représenté 83% du transport intérieur en France, les transports ferroviaires 10%, les autobus et cars 5%, et enfin le transport aérien 2%. Après avoir augmenté en moyenne de 2% par an pendant les années 90, la circulation des voitures (mesurée en véhicules-kilomètres) en France a peu à peu ralenti, ne croissant plus que de 0,6% par an entre 2000 et 2004, année de “stabilisation du trafic”. “L’augmentation des prix du carburants depuis 2003 explique en partie la baisse de l’usage de la voiture en 2005”, estime l’auteur de l’étude, Guillaume Wemelbeke. La voiture coûte en effet de plus en plus cher au consommateur, et de ce fait “les ménages ajustent leurs comportements face à la hausse des prix des carburants”, relève-t-il dans son étude sur la “mobilité des Français en 2005”. Non seulement les Français prennent moins la voiture mais ils en achètent moins qu’avant: “La croissance du parc automobile est désormais faible”. Ce sont surtout les prix à la pompe qui douchent l’enthousiasme des automobilistes: ils ont augmenté ces deux dernières années de 24%, note M. Wemelbeke. Le baril de pétrole est passé en effet d’une trentaine de dollars fin 2003 à plus de 75 en 2006, en raison d’une demande mondiale en hausse et de tensions géopolitiques persistantes dans les régions productrices. Cette hausse spectaculaire des prix de l’essence a aussi entraîné une baisse de la consommation de carburant: elle a diminué d’environ 0,8% par an durant la période 1999-2005. Une décrue qui s’explique aussi toutefois “par une baisse de la consommation moyenne des voitures” (6,91 litres pour 100 km en 2005 contre 8,2 en 1990) et par celle de la vitesse moyenne des conducteurs (-6 km/h à 83,1 km/h), selon l’étude. Les autoroutes sont les moins touchées par le recul de la circulation des véhicules particuliers: elle y a augmenté en 2005, mais de 0,6% seulement, après une croissance de 2,3% par an entre 2001 et 2005. Parallèlement à la baisse de la circulation automobile, la fréquentation des transports collectifs est en constante progression. “Ils bénéficient d’une augmentation et d’une amélioration de l’offre mais aussi de prix attractifs”, comparé à la voiture, souligne l’étude sur la mobilité des Français. Depuis 1996, la circulation par transport collectif n’a cessé d’augmenter tous les ans (sauf en 2003), en particulier pour le ferroviaire (trains et métro) et surtout à Paris. Selon l’étude, les tarifs des transports collectifs n’ont que “modérément” augmenté depuis 1999, avec une hausse moyenne annuelle de 1,8% soit “à peine plus vite que l’inflation (+1,5%)”. Le secteur profite également de la progression des subventions publiques. Pour les longs trajets, c’est le TGV qui porte la croissance de la circulation, au détriment du transport aérien, lorsque les deux modes de transport sont en concurrence. La circulation sur les vols intérieurs, qui avait progressé fortement entre 1990 et 2000 (+2,9% en moyenne), s’est repliée en 2005 à ses niveaux de 1995. En revanche, vers l’étranger, la circulation des Français en avion progresse, avec notamment une hausse de 7,8% en 2005.

    The only bad news is airline flights to foreign places. We ought to be able to fix that I would have thought.

    Serious stuff here and good news for those like me who want to use the price system to fix things.

  2. Chris O'Neill:

    Re#40 “If we can avoid ice ages and cold winters, and expose more land area currently made useless by ice coverage, why shouldn’t we embrace climate change?

    Has the IPCC done a cost-benefit analysis of climate change?”

    Rather ironic someone calling themselves “Crocodile Hunter” aka Steve Irwin should speculate about benefits of global warming when the Great Barrier Reef is in great danger of being destroyed in the lifetimes of people alive today. Not to mention that Australia in general is already suffering substantial reductions in rainfall and increases in evaporation that will get worse as global warming progresses.

    Maybe places that are covered by snow for a lot of the year will get some benefit from global warming but Australia is not one of those places. Australia will be a major loser from global warming.


    I think everybody will loose(Nature doesn’t know what Man-Made borders are), maybe some individuals are able to create a very good adapted life sustain system at the poles, while the rest of the world goes down in chaos?
    Also “places” in snowy areas will be effected by collapsing balances of ecological systems.
    Lifeforms wich can fast mutate and adopt to the changing enviroment will make plagues and destroy other life by taking all the food(I think these are mainly simple organism, organism with fast lifetime, eg. birth rate).

    It will be like some have reserves and once these gone it’s all anarchy.

  4. Grant:

    In addition to the “survey” of AGW in the Economist, there’s this fascinating editorial:

    It seems to me that the piece doesn’t do a very good job on the science, but doesn’t do *that* bad a job either. It definitely tends to underplay the risk with statements such as, “The bottom end of the range would make life a little more comfortable for northern areas and a little less pleasant for southern ones,” “450ppm is reckoned to be ambitious and 550ppm liveable with,” and “The system could right itself or spin out of human control.”

    However, the encouraging aspect of the editorial is that it emphasizes the need for action. Now. It also points out that even a small chance of catastrophic climate change is sufficient motive to *do* something. Furthermore, it points out that the cost of doing so is unlikely to be prohibitive: “And the slice of global output that would have to be spent to control emissions is probably not huge,” “Some models suggest there would be no cost; others that global output could be as much as 5% lower by the end of the century than if there were no attempt to control emissions. But most estimates are at the low end – below 1%.” They’re also unafraid to name names: “Although George Bush now argues that America needs to wean itself off its dependency on oil, his administration still refuses to take serious action.”

    Perhaps the most important aspect is that the issue is getting such high visibility. Global warming is the *cover story* in this issue of the Economist. And instead of taking the old conservative line, arguing that it’s all a bunch of left-wing hoopla, the issue treats AGW as an established fact. I think the denialists should listen to the Wagnerian soprano doing her warm-ups.

    The biggest omission, in my opinion, is consideration of the cost of *not* acting. Even if it costs 5% of global output to act, the cost of inaction seems to me to be drastically higher. But for a conservative financial magazine to address the issue at all is a breakthrough; to do so with anything near realism is cause for celebration.

    Humorous note: you know you’re thinking about AGW too much when … you see a tag-line for a story, “Fancy a Swedish Model?” but instead of thinking of the Swedish bikini team, your first thought is, “I wonder what’s different about Swedish GCMs?”

  5. Chris Rijk:

    I’ve now managed to read most of the survey in The Economist on AGW. The remaining pages (ie most of the article) were definitely better on average, I’d say. Still room for improvement – eg, though they covered ice melting on Greenland etc vs new formation, I don’t think they mentioned the satelite based gravity measurements to determine the net changes. There’s a bunch of things I think they missed, but since I haven’t read it all, I can’t be sure.

    The part on feedbacks was good, though very brief. They also made it completely clear later on that the range of potential warming also depended on how the world’s economy could change by 2100, not just uncertainty in the models – but still didn’t give the ranges for (say) 2x CO2. I remember a brief article covering an aspect of AGW in The Economist a few months ago, and they seem to have changed their thinking on that since then – well, assuming that they don’t change back, given that different writers would cover things in different ways.

    [Response: We’ll do a proper survey of their survey once I get my hard copy on Friday…. – gavin]

  6. Phillip Shaw:

    As one approach to generating a rough order of magnitude estimate of the cost of NOT mitigating AGW consider building a multi-billion dollar New Orleans magnitude levee system around each of the major American coastal cities, including: Boston, Providence, New York, Newark, Philadelphia, Baltimore, Washington DC, Richmond, Charleston, Jacksonville, Daytona, Miami, Tampa, Biloxi, Galveston, Houston, Corpus Christi, San Diego, Los Angeles, Santa Barbara, San Francisco, Portland, Tacoma and Seattle. Add to that the cost of having to rebuild EVERY commercial port facility (and many airports) in America to accomodate the higher sea level. Add the cost of relocating the hundreds of thousands of coastal residents who live outside of cities we can protect with levees. Go ahead and add in any other AGW-related disruptions that come to mind. And finally, add in the cost of converting from a petroleum-based economy to something more sustainable because, whether we like it or not, oil is running out. It quickly becomes apparent that ‘Business as Usual’ is the most expensive choice we can make.

  7. Steffen Christensen:

    Busy thread – nice to see the diversity of opinion out there! Re: #36 – Alastair’s comment about not being able to test climate against the future results. First, saying it again and again doesn’t make it so. That never works. Second, while there are legitimate questions about “what is being modelled in your GCM”, and “will feedbacks with small effects so far become large in the future, and mangle these results”, the philosophical argument that the future hasn’t happened yet so modelling is naive at best is quite weak. If true, that would apply equally to, among others, astrodynamical models of the motion of solar system bodies, which have had a spectacularly successful track record. JPL’s DE405 model of solar system motion, for instance, routinely predicts motions of the major bodies to within 0.000003%, or 100 kilometers at the orbit of Saturn, 50 years in the future ( ). They test that model, among other methods, by running it backwards in time and comparing with observations. It is also accurate enough to navigate spacecraft over the solar system, of which there are a good many. Further, it is exquisitely accurate at predicting eclipses, occultations, transits and so on, many of which have sub-second accuracy. I’m not saying that we’re at that kind of precision in the GCMs, but it’s just ludicrous to say that the lack of independent testing means that you shouldn’t have confidence in the results. Citizens of the whole planet rely on the fact that no asteroid is going to smash into them next month or next century – and guess what is predicting the orbits and calculating risk numbers ( )? An untestable model.
    Third, the models do share the same physics (more important than the specific algorithms used, by the way), and so will tend to give the same results that way. Fortunately for us, the universe shares those same physics as well. For instance, JPL has their DE405 integrator; I have my own integrator I wrote from the ground up. Mine uses pure Newtonian gravity and a Cash-Karp integrator right out of Numerical Recipes in C. However, because we’re both using the same physics, when I seed it with numbers out of the DE405 runs, it generates planetary motions that are pretty darn accurate all the way out to the limit of DE405’s range. I wouldn’t send a spacecraft to Pluto using my own orrery, but I would bet a week’s pay that the Earth will be where my program says it will be in 50 years. That’s the power of modelling for you.

    Thanks, folks. I apologize for the rant.

  8. Crocodile Hunter:

    Re #56: add in the cost of converting from a petroleum-based economy to something more sustainable because, whether we like it or not, oil is running out

    If oil is running out regardless, what has converting away from it as an energy source got to do with a cost-benefit analysis of global warming?

    And why does a sea-level rise of 14cm-43cm by century’s end require us to build New-Orleans-size levies around every major coastal city? Or rebuild EVERY port?

    And then we have #52 and #53: doomsayers sans analyses.

    Given the underwhelming response to my simple request for cost-benefit analysis, you’ll forgive me for concluding that those who advocate drastic action do so on the basis of ideology, not rationality.

  9. astley:

    I would be interested in any comments concerning possible cooling risks and risks associated with low levels of CO2. I thought the earth is colder and CO2 levels are lower now, than at anytime in last 200 million years. What were CO2 levels say 100 million, 65 million, 36 million, and 3 million years ago?

    The CO2 level dropped to about 180 ppm at the end of the last few glacier periods. The Rusian climatologist, M.Budyko, in his book “Climatic Change” stated that total glaciation would occur at around 150 ppm. Is that correct? If not, at what level would complete glaciation occur? At what level does photosynthesis stop?

    How would the earth react to a short term cooling event, say a medium size impact event, without the heat that was in the past stored in the oceans? I thought the deep ocean is now minus 2C to plus 5C where it was I believe in the past 10C to 15C. Is that correct?

    Is the IPPC only concerned with warming?

  10. Mark Bahner:

    “Is the IPPC only concerned with warming?”

    No, the IPCC is only concerned with getting more funding. That’s why the IPCC Third Assessment Report’s “projections” were unfalsifiable pseudoscientific nonsense. And that’s why their Fourth Assessment Report’s “projections” will be the same.

    And why does no one in the “climate change community” (e.g. Real Climate) or scientific journals (e.g. “Science,” Nature…or the hilariously named “Scientific” American) call the IPCC on their pseudoscientific nonsense?

    See statement #1.

  11. Grant:

    Re: #58

    Given the underwhelming response to my simple request for cost-benefit analysis, you’ll forgive me for concluding that those who advocate drastic action do so on the basis of ideology, not rationality.

    Perhaps one of the reasons we’re reluctant to do a “cost-benefit analysis” is that we’re not sure what it is. It conjures images of a formal economic procedure, and we don’t know what that is or how to do it. Perhaps it’s as easy as estimating the costs and estimating the benefits; if so, we can take a stab at that. But probably the most common occupation of regulars here is *scientist*. If I went to a blog for economists about the economics of global warming, and asked them to do an analysis of the TOA energy budget or comment on the appropriateness of 1-D layer models in borehole temperature reconstructions, they’d probably feel a little daunted. I wouldn’t interpret their lack of response as ideological.

    Another reason may be that we’re suspicious of those who would put a dollar value on human (or other!) life and human misery. It seems that cost-benefit analysis may be a fancy way to “discount” what’s really valuable, in order to suggest that action on global warming will ruin our economy. And the greatest burden of global warming is likely to be borne by the poorest people, those in 3rd-world countries. Very few of us trust economic analysis properly to account for the value of their lives and the cost of their suffering.

    Probably the reason many of us are motivated to action on global warming is that it will disrupt ecosystems, bring about more natural disasters, and threaten food and water supplies. The destruction and misery wrought by Hurricane Katrina isn’t ideology; it’s fact. Whether or not Katrina was a result of AGW, we don’t know, but it’s very likely that AGW will lead to a marked increase in such disasters. And, changes to the hydrologic cycle may bring our economic, nay our life-support systems, to their knees.

    From what I’ve learned, the last time earth saw a global temperature increase as large as we expect, in as short a time, was the Permian-Eemian Thermal Maximum (PETM). The consequence was: the death of 90% of species on earth. What’s the cost-benefit analysis of that?

  12. Jeffrey Davis:

    And why does a sea-level rise of 14cm-43cm by century’s end require us to build New-Orleans-size levies around every major coastal city? Or rebuild EVERY port?

    That’s what some models predict.

    James Hansen has pointed out that the fossil record is another model. And that the last time temps were 3C higher that seas were 25m higher. (That’s ~100 ft. If seas rise 100ft, Florida looks like, well, a sting ray’s tail.) Hansen admits that there are no computer models that share that prediction. Still, the historical record should have an impact on our thinking, don’t you think?

  13. Alastair McDonald:

    Re #57 Steffen, you makes three very good points.

    First you argues that repeating a fact does not make it true. However, neither does it make it false. Of course everyone has a right to believe what they like, but I wonder what you think the global temperature will be in 2100? The computer models say 1.5 to 5.6 C higher than today. That is a pretty large range, and we can only wait until 2100 to know the answer.

    Your second point is “the philosophical argument that the future hasn’t happened yet so modelling is naive at best is quite weak” is also true, but that is not what I am arguing. What I am arguing is that you should only trust models when when they have been verified. The astrodynamical models were verified as long ago as 18th century, when the return of Halley’s comet was accurately predicted. But the dynamical system which describes the Solar System is much simpler than that which describes the Earth’s atmospheric system. As Henri Poincare, the father of chaotic dynamical systems, once wrote:

    “Why do the rains, the storms themselves seem to come to us by chance, so that many persons find it quite natural to pray for rain or shine, when they would think it ridiculous to pray for an eclipse?”

    The third point is a common misapprehension, that the climate models are based on physical laws similar to those used in your integrator. There are two differences. In your integrator, there are a finite number of planets which are all handled using Newton’s well known laws. In the case of the weather/climate there is an infinite number of molecules, and so they cannot be individually modeled using Newton’s laws. Moreover, the greenhouse effect depends on quantum mechanics, which is not only much newer than Newton’s laws it is also much more complicated. Hence its effects are paramaterised along with the clouds which are also too complicated to simulate in real time. You rightly claim that you can predict the position of Pluto up to 50 years ahead. However, neither the global warming sceptic Gray, nor NOAA can predict the number of hurricanes five months ahead!

    Modelling the climate is a diffent thing completely from modeling planets, and we have only one chance to get it right. Any criticism of the climate models should be fully investigated, not brushed aside as has happened with the MSU results. The only check on the models prior to 2100 is that criticism. If we have to wait until then to discover that the models are wrong, it may be too late!

  14. Grant:

    Re: #60

    No, the IPCC is only concerned with getting more funding.

    Your entire comment is ad hominem. Maybe that’ll be persuasive to the naive, but not to very many here.

  15. astley:

    Re: 61
    “Probably the reason many of us are motivate to action on global warming is that it will disrupt ecosystems, bring about more natural disasters, and threaten food and water supplies”

    Two comments:
    1. What would be the consequent of a Younger Dryas Part 2 be, in terms of climatic disruption and food supplies? Humanity has roughly a 6 week reserve of food. The rapid climatic change events “RCCE’s” of the so called glacier period appear based on the data to be periodic. I would recommend Paul Mayewski’s book “The Ice Chronicles” which presents the results of the latest Greenland Ice Sheet data, analysis. The RCCE’s start in less than a decade. The Greenland Ice sheet cools as much 30C during RCCEs. The Greenland ice cores show an 800 times increase in dust levels in the ice cores when RCCE’s occur during the glacier period. An 800 times increase in dust implies a drastic increases in windness and desertification. How and how quickly the Holecene warm period will end, needs to be discussed, if not by the IPCC then by independent climatic experts.

    2. I am 110% in support of your comment that ecosystems need to protected, third world countries need to be helped, and conservation of energy use is a good thing. But rather than a complex CO2 trading system, which will not help the ecosystem or third world countries, tax energy use(not CO2 use) and use the revenue to directly protect ecosystems and help third world countries.

  16. David B. Benson:

    Re #61: grant, I believe you mean the Paleocene-Eocene Thermal Maximum (PETM) of about 55 million years ago. This was enough to end the lines of large mammals, which then had to reevolve along new lines. For example, hippos and whales began evolving right at the end of PETM. The end Permian extinction (90%) is now thought to be related to an asteriod impact, but nothing is definitive yet.

  17. Barton Paul Levenson:

    Re #60 and “No, the IPCC is only concerned with getting more funding. That’s why the IPCC Third Assessment Report’s “projections” were unfalsifiable pseudoscientific nonsense.”

    If your life were at stake, would you be able to write down the equation of radiative transfer? What makes you think you know enough about the science involved to make comments like you make?

  18. Hank Roberts:

    Always Google when tasty bait is being pulled past on a long line with a hook:

  19. Hank Roberts:

    Alastair, I’m puzzled what you mean above when you say the MSU (Christie) satellite temperature results were “brushed aside” — are you referring to the lack of news coverage when Christie wrote Science agreeing that the error was real and agreeing to the correction?

    Ray Pierrehumbert mentioned it earlier here:

  20. Mark Bahner:

    Grant writes, concerning my comment #60, “Your entire comment is ad hominem. Maybe that’ll be persuasive to the naive, but not to very many here.”

    OK, how about some straightforward and basic scientific questions for the authors of Real Climate:

    1) Is it necessary for projections of future events (e.g. the IPCC TAR projections for methane atmospheric concentrations, CO2 emissions and atmospheric concentrations, and resultant temperature increases) to be falsifiable, in order for them to be scientific?

    2) Are the projections of methane atmospheric concentrations, CO2 emissions and atmospheric concentrations, and resultant temperature increases in the IPCC TAR falsifiable? Please consider especially the IPCC warning that:

    “Scenarios are images of the future or alternative futures. They are neither predictions nor forecasts.”

    3) If the projections in the IPCC TAR *are* falsifiable, what hypothetical future events would falsify them?

    4) If your answer to #1 is “yes,” and your answer to #2 is “no,” have you ever pointed out (e.g., on Real Climate) that the projections in the IPCC TAR are not scientific? If not, why not?

    5) If your answer to #1 is yes, and #2 is no, have you ever seen any paper in Nature or Science that points out that the projections in the IPCC TAR are not scientific? If not, why do you think that is?

  21. David:

    Croc hunter, suggest you start with the list of papers below to find our more about the cost of climate change. If you want more, then do a cite search (like the rest of us do).

    These may not be the best papers, but are a start. Things look potentially rather ugly for higher warmings. BTW watch out for tricks used to fiddle the story (such as discount rates making future losses artificially near zero).

    Roughgarden, T. and Schneider S.H., 1999. Climate change policy: quantifying uncertainties for damages and optimal carbon taxes, Energy Policy, 27, 415-429.

    Schiermeier, Q., 2006. The costs of global warming. Nature, 439, 374-375.

    Nordhaus, W.D., 2006. Geography and macroeconomics: New data and new findings. Proceedings of the National Academy of Sciences, 10.1073/pnas.0509842103, 8pp.

    Keller, K., Hall, M., Kim, S-R., Bradford, D.F., and Oppenheimer M. 2005. Avoiding dangerous anthropogenic interference with the climate system. Climate Change, 73, 227-238.

    Barker, T., Köhler, J. and Villena, M., 2002, The Costs of Greenhouse Gas Abatement: A Meta-
    Analysis of Post-SRES Mitigation Scenarios. Environmental Economics and Policy Studies
    5, 135-166.

    Barker, T., Foxon, T. Köhler, J., Anderson, D., Gross, R., Leach, M. and Pearson, P., 2005. University of Cambridge and Imperial College London Submission to the Stern Review (UK). 20pp (available from

  22. Alastair McDonald:


    First I must apologise for a mistake I have made. In your link to Ben Santer it states

    “For well over a decade, climate skeptics undercut the science on climate change by citing satellite temperature records, which showed that the atmosphere was not warming. But all of this changed last August when three papers published in Science (2005, 309, 1548-1551; 1551-1556; 1556-1559) showed that the satellite data were not as accurate as people had reported. When the data were corrected for problems such as satellite drift, researchers found that the earth’s atmosphere has been heating up.”

    The third paper is not about satellites, but about radiosondes which were also showing that the upper troposphere was not behaving as the models predicted! I attributed its authorship to Santer, but in fact the lead author was Sherwood.

    Santer was the lead author of the second paper. Its abstract concludes:

    “These results suggest either that different physical mechanisms control amplification processes on monthly and decadal time scales, and models fail to capture such behavior; or (more plausibly) that residual errors in several observational data sets used here affect their representation of long-term trends.”

    So it is only plausible that the models are correct, not a scientific fact! Everyone is congratulating themselves that they have “proved” global warming is happening, but is brushing aside the point that the models are still not in the clear.

    Your Santer web page also refers to the Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences Report. In its executive summary it says:

    “Although the majority of observational data sets show more warming at the surface than in the troposphere, some observational data sets show the opposite behavior. Almost all model simulations show more warming in the troposphere than at the surface. This difference between models and observations may arise from errors that are common to all models, from errors in the observational data sets, or from a combination of these factors. The second explanation is favored, but the issue is still open.”

    What I am saying is that the sceptics are partly right and the believers are partly wrong. No one is perfect :-)

    NB The upper troposphere is part of the lower atmosphere.

  23. Crocodile Hunter:

    Re #70:

    BTW watch out for tricks used to fiddle the story (such as discount rates making future losses artificially near zero)

    And watch out for the classic ideological academic’s trick of answering a simple question with a long list of citations.

    I could go and read all those papers, but it would be an enormous chore. How about you summarize the main arguments for me?

    If David Suzuki is correct (“every scientific body has said that global warming is a far greater threat to our security than any terrorist act”), surely a summary of the evidence behind that argument would be a relatively straightforward exercise?

  24. Lawrence McLean:

    Re #72
    It is not that difficult to find out for yourself.

    It would be nice if global warming was just a nightmare and that David Suzuki was wrong. However, poo-pooing an entire science just because you don’t like it is ridiculous. If you believe the spin doctors, otherwise known as climate change skeptics then nothing will ever be clear to you.

    The way I see it, the climate change skeptics, are behaving like lawyers, they are not seeking the truth, they are just trying to prop up their dogma by whatever means.

    In summary, yes, it is a straightforward exercise and it has been done, you just have to look it up!

  25. William Astley:

    Re: 72, Climate Change Skeptics? RCCE Colder Vs GHG Warmer?
    David Suzuki is a great environmentalist; but he is mistaken concerning the relative danger of a warmer vs. colder planet. We live in a two pole ice age, the coldest period in the last 200 million years. For the last 600kyrs years there was been a recurring pattern, a 10kyr so called “warm” period (massive ice sheets both poles, during the warm period) and a 90kyr very cold period (1/3 of the land mass and vast areas of the high latitude oceans covered in ice.) During the last cold period, the so called Wisconsin ice age, the North American ice sheet moved as far South as 40 degrees latitude. The Canadian-US border is of course the 49th latitude.

    The change from cold to colder, may happen, in less than a decade, if it is triggered by the external forcing function that triggered the Younger Dryas, RECC. The Rapid Climate Change Events (Rickeys) were discovered in the 1993 GISP2, Greenland Ice Sheet core. The RECCs were once believed to have been triggered by abrupt stoppage of the Gulf Stream. Seager et al (2002)’s paper, debunked that myth. His and others’ climate models show that the Gulf Stream warms Europe 1 to 2C. (Most of the east Atlantic coast warming is due to the massive Rossby wave that is created by the jet stream as it moves east to west across the Rockies. See Seager’s article for a great explanation of Rossby waves and Atlantic climate. Seager et al’s, (2002) paper was used as the basis for an article that was published in the July-August 2006 American Scientist which I would highly recommend.)

    As a stoppage of the Gulf Stream can not explain the periodic 10C to 30C drop in less than a decade on the Greenland ice sheet which is accompanied by a massive increase in the Polar Circulation Index (very, very windy, during the RCCEs), Seager notes that there is at present no explanation as to what could cause the observed very rapid drop in temperature. During the Younger Dryas, the Atlantic ice pack in the winter extended as far south as Northern Spain. Great Britain’s interior had a summer high of 10C and a winter low of -5C. (Warmer than central Europe due to the Rossby wave.)

  26. Crocodile Hunter:

    Re 75: Thankyou. Very informative.

    Since the climate can change so abruptly and for no readily apparent reason, why should we be particularly concerned about the slow, long-term effects of GHG emissions? It may even be true that we are helping stabilize the climate.

    Somehow I get the feeling that ecosystem collapse is not the real problem for environmentalists. It is ecosystem collapse that might possibly be linked to human activity. But if the climate can change rapidly and seemingly without cause, to what extent can one meaningfully attribute climate change to CO2 emissions?

    Put another way, I have always found the butterfly-flapping-wings-in-Tahiti-causes-tornado-in-Texas explanation of chaos to be utterly fallacious. If the butterfly in Tahiti causes the tornado in Texas, then so does every other flap of a butterfly’s wing that is within the speed of sound of the Tornado. If every butterfly is a contributor, then no single butterfly is the cause, and it is nonsensical to speak of the butterfly in Tahiti causing the tornado.

    It is the same kind of counterfactual error people make when examining their own actions: “if only I had done X instead of Y”. Such reasoning always assumes that the almost infinite number of variables other than X and Y remain unchanged. But that is never the case. If you had done X instead of Y then A would have gone differently, and so would B, C, D, … and most likely the desirable outcome you imagine would have occured would not have happened anyway.

    This ramble has a point: to do a cost-benefit analysis of GHG reduction, you have to be able to predict the counterfactual: what happens if we don’t reduce GHGs? If you don’t know why the climate sometimes changes rapidly, then how can you answer the question?

  27. Marina:


  28. Gar Lipow:

    >Given the underwhelming response to my simple request for cost-benefit analysis, you’ll forgive me for concluding that those who advocate drastic action do so on the basis of ideology, not rationality.

    Actually, I used to give replies to this almost every thread. However I got the feeling that Gavin at least was getting sick of this, as were possibly some of the readers. Of course the reason I kept repeating myself was that the question keeps coming up.

    So the answer is we can phase out fossil fuels at prety close to zero cost. The reason is that due to various market failures all sorts of efficiecy measures tend to be overlooked. If these efficiency measure were put into to place we could save a great deal of the energy, and a lot of the money we spend on fosil fuels besides. That is we could greatly increase the amount of GDP we produced per unit of energy.

    As we phased in those savings we could phase in carbon neutral sources of energy (solar, wind, and so forth). These would be more expensive than fossil fuel energy sources. But as these more expensive sources were being used more effectively the overall energy cost per unit of GDP would be the same. In other words we would use fewer more expensive BTUs per unit of GDP, thus producing the same GDP and growth rate we do now.

    Note this would work regardless of whether absolute energy consumption was reduced. There is plenty of solar energy available; it is just more expensive to utilize than fossil fuels. If increase GDP per unit of energy consumed, then we can afford to pay more those units of energy whether we consume a little or a lot. In other words, Amory Lovins points about “negawatts” remain valid even if total world energy consumption increases.

  29. Crocodile hunter:

    So the answer is we can phase out fossil fuels at prety close to zero cost. The reason is that due to various market failures all sorts of efficiecy measures tend to be overlooked.

    You need to justify that statement. On face value it is highly implausible – each year China alone is adding almost as much power generation capacity as the whole of Britain. There’s a possiblity they could do a lot more of that with nuclear, but it is not going to be at zero cost. And I’d love to see your cost estimates of adding that much capacity annually with solar, wind, or any other renewable souce.

  30. Gar Lipow:

    Zero cost compared to continuing to use fossil fuels. For a bit on this look at the web site in my link. Also check out the web Rocky Mountain Institute ( Over the course of 30 years we can phase out fossil fuels fairly easily – replacing infrastructure as it needs replacement in any case. You are going amortize fossil fuel plants over the course of 30 years any way – as well as things like cars and factory equipment and space heaters that consume fossil fuels. As you amortize the fossil fuel consuming equipment replace them with more efficient equipment that can use renewable energy (electricity or biofuel). The incremental cost of replacing infrastructure with more efficienct infrastructructure is tiny. Less than zero compared to the NPV of fossil fuel savings. The renewable sources will be more expensive than fossil fuels (not all of them, but on average). But again you are replacing power plants and refineries and such which have to be replaced anyway – so your cost is the incremental difference between renewable sources and fossil fuel sources. And the incremental costs of renewable sources is less than the NPV of fossil fuel savings. So it is zero cost *compared* *to* *continuing* *to* *use* *fossil* *fuels* *at* *present* *efficiency*. Before looking at the empirical data, you need to understand the principle. More efficiency – a cost saving. More renewables, an expenditure. The savings and the expenditure net out compared to continuing to do the same thing. Now with that in mind, go to the RMI web site, and to mine as well. Ignore what is in my opinion hydrogen hype at RMI, and look the RMi efficiency proposals.

  31. Crocodile Hunter:

    From your website:

    The next two chapters will show that industrial infrastructure may be upgraded over the
    course of thirty years to use about 75% less energy per unit of output – at very little
    additional cost.

    My baloney meter just went into overdrive. Unfortunately, we don’t have access to the next two chapters. Energy is a significant cost already to most industry. If there are obvious savings of 75% to be had, why is industry not already doing it?