Scientists respond to Barton

by Gavin Schmidt and Stefan Rahmstorf

Many readers will be aware that three scientists (two of which are contributors to this site, Michael Mann and Ray Bradley) have received letters from Representative Joe Barton (Texas), Chairman of the House Energy and Commerce Committee specifically requesting information about their work on the ‘hockey stick’ papers (Mann et al (1998) and Mann et al (1999)) as well as an enormous amount of irrelevant material not connected to these studies.

Many in the scientific community would welcome any genuine interest in climate change from the committee, but the tone and content of these letters have alarmed many scientists and their professional organisations. In the words of Alan Leshner, CEO of the American Association for the Advancement of Science, the Barton letters “give the impression of a search for some basis on which to discredit these particular scientists and findings, rather than a search for understanding.” Other organisations and individual scientists have also expressed strong concerns:

The individual responses have now been delivered (and you can read them here):

These responses emphasise two main points that we have explained in great detail in earlier postings on this site:

  1. There is no case for casting doubt on the scientific value and integrity of the studies by Mann et al. – they have been replicated by other scientists, the data and the computer code are available in the public domain (including the actual fortran program used to implement the MBH98 procedure), and many other studies with different data and methods have confirmed the prime conclusion: that it is likely that the late 20th Century is the warmest period of at least the past one thousand years.
  2. The above studies are just one small piece of evidence in a very solid scientific case that humans are now altering the climate – and with or without this piece of evidence, this case is firm (see our post “What if the Hockey Stick were wrong?” or the commentary on Prometheus).

The real question we are faced with is not whether humans are changing climate. The science on this is clear, and decades of research have culminated in a scientific consensus on this point. The real question now is what we need to do about it. A Congressional committee concerned with energy could be – and indeed should be – a key player in exploring policy options to deal with the global warming threat. We hope that after studying the responses by the scientists, they will make a start.

147 comments on this post.
  1. John Hunter:

    I am unsure why you have not posted the following, which I sent on 19 July:


    I find it interesting that Michael Mann, in his letter to the House Committee, describes Steve McIntyre as a “mining industry executive” and McIntyre’s own biography ( describes him as working “in the mineral business”. Both descriptions are pretty euphemistic. Around the time of the writing of McIntyre and McKitrick (2003; the Energy & Environment paper) and of the above biography (dated in October 2003), McIntyre was actually a “Strategic Adviser” to CGX Energy Inc. who describe their “principal business activity” as “petroleum and natural gas exploration” ( CGX Energy Inc. occupy the same Canadian address given for McIntyre in McIntyre and McKitrick (2003), an address which is also occupied by Northwest Exploration Company, another business which apparently engages in oil and gas exploration (or at least a company with the same name does). McIntyre was also President of Northwest Exploration Company.

    Now, if you believe that you can divorce the message from the messenger, then this may all be irrelevant information. However, I still find it interesting that nowhere in McIntyre’s biography or in his other public writings can I find any mention of his involvement in the oil and gas industry.


    You may consider this as “political”, but so is much of this thread (as others have pointed out). The point is not to pretend that everyone who has any connection with the fossil fuel industry should be disbelieved, but rather to indicate a small but significant discrepancy in the common description of Steve McIntyre. I know it is only a marginal piece of information, but so is much that is on this thread.

    Anyway, an emailed reason for rejection would have been nice. However, if you are snowed up with postings and mine is just in the queue, please ignore this.

  2. Lynn Vincentnathan:

    This Barton case exemplifies Michel Foucault’s dictum. We’ve all heard that “knowledge is power,” but Foucault said “power is knowledge” (meaning that power determines knowledge). As a post-structuralist he was going beyond cultural (binary frame) determinism. The Barton case is a blatant attempt of power to control and determine knowledge. As mentioned, I’m not a determinist. I see a reality principle (a term psychologists use for non-psych variables): even if the powerful persist in distorting and covering up GW science, and GW is true according to or beyond what CC scientists are telling us, eventually GW will impact humanity to an extent that powerful contrarians like Barton & Co will be quashed, along with a lot of other harm to a lot of innocent people. I pray we avert such disaster rather than head straight into it, led by unscrupulous shepherds like Barton.

    I agree with #16 that “climate disruption” is a better term; one of the contrarian arguments re climate change is that the climate has always been changing and always will. But we can keep all the CC acronyms if we call it “climate catastrophe.” However, I somehow doubt that even such an “alarmist” term would get people to turn off their engines in drive-thrus.

  3. Christopher Brown AICP:

    Great letters. It’s good to see some well written responses to the continuing push of the anti-science/reason forces that dominate the headlines everyday. They should be published in newspaper editoral pages and made required reading for undergraduates.

    Keep up the fight.

  4. Steve Latham:

    John, thanks for #49. WRT #40 and Lomborg, did anyone notice that preventing war, etc, in Africa (or at least not promoting it economically or supplying arms) wasn’t promoted as a good way to help the environment? I know in terms of money that militaries around the world eclipse aid and other priorities. I wonder what the CO2 contributions of militaries (especially airforces) are to the Earth’s present burden? How about other influences of war on climate?

  5. Steve Bloom:

    Re #51: Great research! But didn’t McIntyre state that he had “no competing interests” in one or more of his paper submissions? And hasn’t he described himself as being in some manner retired from the “mining industry”? Has he failed his own standard of transparency? Curiouser and curiouser.

  6. Stephen Berg:

    Re: #51 and #55,

    This matter about McIntyre and McKitrick’s backgrounds should be the issues investigated rather than those of Drs. Mann, Bradley, and Hughes.

    It is a far larger scandal that researchers neglect to disclose their competing interests (i.e. those who receive funding from the fossil fuel industry but lie or obfuscate about this information), to the scale where a full-fledged public inquiry and “outing” of these researchers would be far more productive than going after those whose goals are purely scientific in nature.

    Following such an inquiry, the public would have a real idea of which researchers to trust, since they would know exactly what specific researchers’ goals were. (They could then choose to ignore the statements by people like Fred Singer, Pat Michaels, Sherwood Idso, etc. having known they are harping fossil fuel industry positions.)

  7. dave:

    Re: Coming Up on Science Friday

    Tomorrow, NPR’s Science Friday will feature in the first hour a discussion of Barton vs. Mann, Bradley and Hughes. Here’s the background page at the NPR site.

    Also, I am quite disappointed in the lack of news coverage of this story. Aside from the usual sources e.g. NY Times, BBC and now NPR, there is relatively little beyond a few other weblogs about this issue. What is at stake is free independent scientific inquiry as most RC readers and contributors already know.

    What will have to happen to get this discussed more widely and taken more seriously?

  8. Quilibet:

    Where is the evidence that mankind is “chaning the climate”?


  9. dave:

    Well, there’s no evidence at all that we are “chaning the climate”. To be fair, perhaps “chaning” is based on the English noun/verb “chain”, the verb meaning “connect or arrange into a chain by linking”. There appears to be little evidence that we humans are altering the climate by linking (some unknown) things together into a chain. There is, however, considerable evidence that humans are changing the climate by our emissions of fossil fuels but to understand that, you need to be familiar with the etyomolgy and the meaning of the word “change” used as a verb. Anyway, I’m a pushover and I like to be fair toward all points of view, just as Texas Congressman Joe Barton is.

    Sometimes I think the really BIG mistake Nature made was at the beginning of the Pleistocene between 1.8 and 1.6 million years ago after the initial appearance of the genus Homo at about 2 million years ago, but that’s a deep subject….

  10. dave:

    Re: my last message: my abject apologies for spelling “etymology” the way I did — or did I do that intentionally? Only the shadow knows…

  11. Florian Boehm:

    RE: #46
    John Finn wrote:
    What is the reason for the sudden sharp upwards inflection just after 1900.

    Mike – your reconstruction shows this rise to be without precedent in the previous 900 years, so I’m interested in your view as to why this particular change in solar/volcanic forcing was so unusual.

    It is not correct that the sudden temperature rise after 1900 is without precedent in the previous 900 years. There are several sudden temperature changes (up and down) in the 1000 years record of Mann, Bradley and Hughes; for instance at about 1150, 1350 or 1450. The difference is that these were short swings in the temperature curve. What is unprecedented in the 20th century temperature rise is its continuation until today to a level clearly above the pre-1600 noise level of the Mann et al. curve.
    The temperature rise at the beginning of the 20th century can be well explained by a combination of natural and anthropogenic factors (see for instance model calculations of T. Crowley in Science 14 July 2000, page 270- 277).
    There was an increase in solar activity during the first half of the 20th century known from the sunspot record (following the Damon sunspot minimum). There were also only few volcanic eruptions during this period. Both added to the climate warming seen in the temperature curve. However only the anthropogenic greenhouse effect can explain the continuing temperature rise during the later 20th century.

  12. Jeffrey Davis:

    Re: 38

    The cost of the Kyoto Protocol was pegged at ~$700bn?! I’d no idea that the cost was that low.

  13. Lynn Vincentnathan:

    I just want to apologize to Michael Jankowski (RE #2, 7) for my brash response (#8). While I am working on a anthropological paper, “GW: Fact & Fiction,” it is not primarily about contrarian positions. Only a small section on that will be included, and I am not planning to use anything MJ has written.

    Please, Michael, do continue to contribute to this blog.

  14. rasmus:

    One comment though on the latest developement. I notice that MM (or one of them) have changed their focus from the initial claim about non-centering the principal component analysis (PCA) to the question about cross-validation. They complained for a long time about not getting the original code (now disclosed) and tried to create the impression that science works like accounting or detective work, i.e. that each specific method/test must be EXACTLY replicable for one particular case – a demand that is impossible in most scientific fields since it’s impossible to reproduce EXACTLY the same results in ordinary physics experiments or clinical trials (due to random measurement errors and statistical fluctuations). Even for computations this may be difficult, due to different software configurations (platforms, CPUs, libraries, annd so one). The important point is, however, that universal patterns/laws are replicable. And this is exactly what the results of Mann et al are: the same general features are found in other independent studies. If this is not fulfilled, then the results are not very interesting because then they are not universally true.

  15. Joseph O'Sullivan:

    MBH are doing the right thing. Complying with Barton’s interrogatories is an opportunity to stand up for the facts and climate change science. Hopefully this will get climate change and the political campaign against science the attention it deserves from the federal government, the media and the public.

    A politician asking questions about climate change science seems to be on its face reasonable. Reducing greenhouse gases will require a new and complex regulatory scheme. The science that these regulations will be based on should be thoroughly examined. These regulations will have a major impact on the oil/petrochemical industry so it is understandable that a Texas politician would be especially interested because the oil/petrochemical industry is a major part of the Texas economy.

    However Rep. Barton’s requests are one-sided and seem to be attempts to disparage scientists and manufacture uncertainty in the climate change debate. Intimidation would not be too strong a word to describe this. His requests seem to be a thinly veiled threat to the scientific community.
    Barton does have close ties to the oil industry. He is a sponsor and an advocate for legislation that favors the oil/petrochemical industry but has questionable value, for example subsidies to an oil industry with record profits and a failure to require security measures at vulnerable chemical plants. Oil companies are major campaign contributors to Barton. see
    Barton is also openly hostile to environmental regulations like pollution control. The League of Conservation Voters tracks the voting records of congress people on conservation and environmental issues. see

    I think the best thing is to call Barton’s bluff. Use this as an opportunity to publicize the crisis of climate change and to expose the political pressure on the scientific community.
    The UCS has a good news story.
    Even better, the influential New York Times has weighed in on the side of the scientists in an editorial.

  16. Stephen Berg:

    A letter which I sent to the Energy and Commerce committee:

    “The witch-hunt with respect to climate scientists Mann, Bradley, and Hughes is a waste of resources, since their scientific papers tell all what is necessary to hear.

    It is also an abuse, since your committee refuses to tackle the many problems associated with the highly flawed McIntyre and McKitrick’s papers.

    Your committee should be ashamed of itself and should bring great shame to the US government.”

  17. Klaus Flemloese, Denmark:

    Re 60/Joseph O’Sullivan/turn it positive :

    “MBH are doing the right thing. Complying with Barton’s interrogatories is an opportunity to stand up for the facts and climate change science. Hopefully this will get climate change and the political campaign against science the attention it deserves from the federal government, the media and the public.”

    I agree with this statement.

    Turn the inquiry it into a positive effort to inform the representative Joe Barton (Texas), Chairman of the House Energy and Commerce Committee about the the climate science and also about M&M’s, Soon and Baliunas scientific achivements.

  18. R Xapt:

    “Use this as an opportunity to publicize the crisis of climate change and to expose the political pressure on the scientific community.”
    O’Sullivam #65

    What exactly is the ‘crisis’ of climate change? The fact that we may be experiencing global warming (temporarily or permanently?) is not a crisis per se, is it? So again, what exactly is the crisis?

    Several studies by economists at Yale University have shown that global warming will have a net positive impact on the US economy. If true, this “crisis of climate change” may not be a crisis after all.

  19. beth:

    The Washington Post editorial for today is right on this subject, and an excellent piece describing the Barton affair:

  20. Thermo-dynamist:

    Evolution is the expenditure of energy. Terrestrial energy is finite.

  21. Eli Rabett:

    Re 70, I believe the sun still shines most places. Petroleum in a real sense is stored solar energy

  22. Steve Latham:

    Comment #68 (3:33 pm) hardly deserves a response, but I’m in a strange mood: First, this website is (mostly) about the science of climate change. Climatologists are held to a high standard in terms of independence, disclosure, consensus, etc, in public and political arenas (read what this post is all about). Now we have some economists from Yale who don’t fully understand the consequences of climate change even on climate (because they’re not climatologists and because even climatologists can’t predict the extent of climate change, especially regionally) saying, “Hey, this is a net economic positive for the United States as a whole.” Yeah, I’d like to see the source code for the model they used to make that prediction!

    Secondly, this comment demonstrates a severely nationalist (dare I say bigoted) attitude that an action potentially good for one group of people but demonstrably damaging to another group is well worth following. If the United States wants to wage war (using climate as a weapon) on Tuvalu’s or any other country’s citizens for economic reasons, they had better declare it. Such a declaration would signify a moral crisis. This says nothing of potential inequities in the distributions of costs and benefits among citizens within the United States, but if those calculations could be worked out in advance I’m sure it would be considered a crisis by some.

    [edited – gavin]

  23. rollo:

    Evolution is the transformation of energy.

  24. Gar Lipow:

    I do have one question. Prometheus’s latest column includes the following quote:

    >NCAR’s Jim Hurrell observes, “… it should be recognized that mitigation actions taken now mainly have benefits 50 years and beyond now.”

    So if we were magically to stop all human cause carbon emissions today, we would see no climate change mitigation over the next 20 years at all? I understand that there are other benefits from phasing out fossil fuels. But in terms of preventing climate disruption, are we really too late to prevent any effects in shorter term than 50 years?

  25. Klaus Flemloese, Denmark:

    Joe Bartons inquiry/Chemical industries inquiry/Fishing expeditions

    I will be pleased to draw your attention to a similar action taken by the chemical industry against scientists in US. It is the chemical industry’s lawsuit against Prof. David Rosner and Prof. Gerald Markowitz. The two professors have written a book about how the chemical industries and their trade organisations have tried to hide the connection between cancer and PVC/VCM and between lead pollution and health. The chemical industry is so upset over this books disclosure that they have filed a lawsuit. The layer of chemical industry went during the disposition on a fishing expedition to the files of the authors, peer reviewers, University of California Press and the Milbank Fund. This is similar to Joe Barton’s fishing expedition.

    In addition to this the chemical Industry has hired their own “scientist” to discredit the two professors. M&M have a similar role in their attempt to discredit MBH.

    It looks like that the same master plan is behind the way the tobacco industry, the chemical Industry, the petrochemical industry and other industries are trying to discredit scientists.

    The effect of these inquiries could be that no scientists want to be involved in areas where there could be a conflict with major financial interests. This could be what Joe Barton/American Petroleum Institute/ ExxonMobile/ the chemical Industry/The Marshall Institute/the tobacco Industry etc. aim at.

    I find both cases interesting, fascinating and frightening.

  26. Lynn Vincentnathan:

    RE # 38, 62 & 68 (economists say Kyoto will cost a net $700 bn & not abating GW will have a positive impact on the U.S.). When economists can predict what the stock market will be like a year from now, maybe I’ll start gambling with it, but I’ll never believe what they have to say about the costs & benefits of abating/not abating GW. They are simply wrong. I am confident from my own personal experiences and readings that abating GW (even not figuring in GW harms & the many other harms prevented by implementing abatement measures) will save us money in the U.S. & help the economy up to & possibly exceeding 1/2 reduction of GHGs. By the time we get to that point in 15-20 years (if we start in earnest now), perhaps there will be some new technologies that save us even more money while reducing GHGs (assuming something has not made us all stupid &/or unmotivated to save money & increase profits).

    I cannot understand how GW will be beneficial to the U.S. If you’re (#68) suggesting larger crops in a warming/C02 enriched world, I think that’s wrong. Studies I’ve seen show that CO2 enrichment will cause greater crop damage from weeds & pests, and the increased droughts & floods from GW are not good for crops either. And I believe that the actions that produce GHGs also pollute the soil, acidify it, release toxins, etc. No, we are looking at agri-disaster with continued GHG emissions.

    Furthermore, we should be also looking at reducing GW harms to others in the world, not just figuring whether GW will help or hurt the U.S. What are we, pigs oriented only toward satifying our gluttony? Where are the religious Americans (concerned about helping & reducing harm to others & abating their own sinfulness) when we need them?


    Politics Collides With The Scientific Method
    A bunch of letters from Representative Joe Barton regarding the findings of a study on global warming have caused quite a stir in the scientific community. RealClimate cites the following concerned parties:

    A statement from the EGU
    The American Associa

  28. Eli Rabett:

    I would recommend that folks trying to understand the costs and benefits of mitigation read as starting points, the TAR WG3 report and especially the technical and policy maker summaries.

  29. Peter:

    Thanks for an outstanding and long needed site.
    (Just wish to see this quality and comitment for websites of other fields of science)

    Now to my point. Over the years I have come to find the US right wing Christiansâ?? (at least partly under the lead of the Bush administration) involvement in and distortion of science (exemplified by, but not limited to, climate change, biology-evolution, and medicine-stemcell research. Also see ) so upsetting and revolting that I sometimes have considered to boycott publicizing my own research (in wireless communication systems) in US under the current administration. Is academic boycott an option? What would be the effects if many researchers joined forces?

    [Response: I think you are confusing the scientific establishment (the universities, journals, societies, science agencies etc.) with the other bits of the US (the administration or fringe groups). The scientific process in the US is extremely active and produces some of the best science in the world, boycotting this would be very counter-productive. On the contrary, US scientists need support for education and outreach activities to help remove some of the confusion that exists. – gavin]

  30. Dan Allan:

    It seems that, increasingly, the only area of possible dispute in GW at this point is in the cost to society of mitigation for the cost of GW. This is clearly a very complex question. Does anyone know what the basis of this Yale study was? How much warming did it assume, before concluding that it would have a positive effect on the U.S.? What factors did it consider, beyond the obvious such as heating costs versus air conditioning costs? We’re a long way away from having even a slight handle on the possible costs of global warming. I know this site prefers to discuss the science behind GW itself, but it seems to me that the climate-science battle has already been lost and won, and the impact analysis is going to be the next area of both serious debate and political bluster. Perhaps RC would consider amending their editorial policy and including a guest commentator posting something on this topic. If not, any links to serious articles on this topic would be appreciated.

    – Dan

  31. Michael Tobis:

    #68, though phrased a bit confrontationally, asks the right question. “What is the crisis?”

    The right answer is “we are almost certainly in the process of causing the largest abrupt transition in the global geophysical regime at least over the past 50 million years, and now we are arguing about its severity and suddenness beyond that established fact”. I don’t know how to explain that to people who believe the earth is only 6000 years old, though.

    #68 also refers to “some studies at Yale”. One would prefer actual references before even considering a response.

    It is unclear whether economic arguments are or should be considered within the scope of this forum in any case. I’d appreciate some guidance from the editors on this point.

  32. Lynn Vincentnathan:

    RE #78, I also suggest reading NATURAL CAPITALISM by Paul Hawkens & Amory Lovins ( ). It gives a beautiful vision of the future that we should strive for; then hopefully we can get halfway there. It’s a must read for green engineers & architects.

  33. Thermo-Dynamist:

    RE: 71.

    Sunlight is diffuse. In order to be useable it would have to be concentrated in large batteries of some kind. This would create potential radiation hazards and waste pollutions. Not much different possibly worse then combusting finite petroleum resevoirs.

  34. R Xapt:


    Thank you for approaching the matter like a scholar and a gentleman.

    The three main authors at Yale are Robert Mendelsohn, James Neumann, and William Nordhaus. Mendelsohn has a joint appointment in the Economics Department and the Enviromental Studies Department (in the School of Forestry). Nordhaus is a very well-know and highly-respected economist.

    In 1999, Mendelsohn and Neumann published (Cambridge University Press) “The Impact on Climate Change on the US Economy.” At present, they are working on a follow-up book “Global Warming and the American Economy: A Regional Assessment of Climate Change.” Mendelsohn has published several papers with Nordhaus. A few appeared in the American Economic Review, the most pretigious refereed journal in economics.

    As for Nordhaus, here are a few of his papers.

    “An Optimal Transition Path for Controlling Greenhouse Gases” in Science, 1996

    “A Regional Dynamic General-Equilibrium Model of Alternative Climate-Change Strategies,” American Economic Review, 1996.

    “Climate Impacts on Aggregate Farm Values: Accounting for Adaptation” (with Robert Mendelsohn and DaiGee Shaw), Agriculture and Forest Meteorology, 1996.

    “The Impact of Global Warming on Agriculture: Reply,” (with Robert Mendelsohn), American Economic Review, 1996.

    “What is the Value of Scientific Knowledge? An Application to Global Warming Using the PRICE Model,” The Energy Journal, 1997.

    Here is a link to his home page at Yale:

    All of his publications are listed on his CV (his work on climate change is more recent).

  35. R Xapt:

    #80 Dan, see my post to #81 for links to their work (actually references–they don’t PDF their published work and post it like many do).

    The work done by these folks considers temperature increases that range from 1.5 to 5C between now and 2100. A central message of economics is that people respond to incentives and what Mendelsohn’s work shows, and what non-economists almost always ignore, is that firms/households will respond to climate change in a way that enhances the benefits and reduces the damage.

    Mendelsohn finds that the big winner in global warming is (not surprisingly) argriculture (unless warming is unexpectedly severe). Forrestry is a small winner too. And people living in the North are bigger winners than southerners….

    Bottom line, and to quote Mendelsohn: ” climate change does not appear to be a major threat to the US for the century to come. There is little motivation for expensive crash programs to curb short-term emission of greenhouses gases. The focus of mitigation policy should remain on inexpensive ways to control global emission over the next century.”

    Inexensive ways? Certainly not Kyoto. Taxes, by contrast, are an inexpensive way to control global emission so long as they are structured correctly (such as pollution permits that could be traded in secondary markets, etc). Oh well, I’ve turned the discussion to economics which isn’t the purpose of this forum.

  36. R Xapt:

    Editor/censor–don’t post this but please read on. Your posting policy is terribly biased. You let #72 put up a post in which he calls me a twit and then refuse (to this point) to post my reply. Fair and balanced you are NOT.

    R Xapt

    [Response: Sorry, the original post slipped through. For all contributors, please remember that a certain measure of decorum is required here. -gavin]

  37. Steve Latham:

    To R Xapt: thanks for the references. It was my expectation that the end of my previous comment would get deleted by the editing process, but I accept the fault — I should not have written that regardless of my expectations. I look forward to seeing your rebuttal when it is posted.

  38. Joseph O'Sullivan:

    Its off topic but since this thread started with a comment I made I will respond but only once.

    The fact that there is global warming is now established and even well known scientific skeptics do not contest it. Ecosystems around the world are undergoing disturbances. Economies are not separate from ecosystems. This is a crisis, one that we are causing.

    I suspected the study #68 was referring to is “The Impact of Climate Change on the United States Economy” a book published in 1999. Basically said that the overall effect on the US economy would be a small positive if warming was small and gradual. Cato, Singer and friends loved it, but outside of that you don’t hear much about it.

    For a better discussion Pew published the results of a study last year. US Market Consequences of Global Warming. See the press release
    and the report

    Basically the Pew report said there will be small short-term economic positives but larger long-term economic negatives and the greater the magnitude of the warming the greater the negative economic effects. It also said there are many uncertainties especial when considering the economic consequences of environmental effects so these were not included but these were likely to increase the negative economic effect of global warming.

    The Pew study and the book are cost-benefits analysis (CBA). CBA are controversial. They are very subjective and have been traditionally used, and sometimes abused, to argue against environmental regulations. For a good short discussion see

    One of the most difficult parts of CBA is natural resource damage assessment (NRDA). I have had some experience with nerda as lawyers call it, and it is an extremely difficult determination where there are few clear answers.

    On the economics of climate change UPI has a good news story. See

  39. Dan Allan:

    X rapt (#84),

    I read the Nordhaus links I could find that you pointed to. “Requeim For Kyoto”, “Global Warming Effects On Agriculture”, and one regarding the cost benefit of information related to global warming.

    First, Nordhaus does not strike me as an ideologue – in fact one of his other papers suggested that the U.S. was drastically underestimating the cost of the Iraq war, which has turned out to be true.

    However, I think you are somewhat misrepresenting Nordhaus’ rather more limited conclusions. He never says Global Warming will be no big deal. In his “Requiem For Kyoto…” article, he simply looks at Kyoto’s mechanism for reducing GHG as compared with other theoretical alternatives (they all involve different models of allowing nations to trade rights to emit GHG), and concludes that Kyoto’s mechanism is inefficient. I do think he makes a significant mistake in evaluating the cost of Global Warming overall. Because he is an economist, he chooses to define cost as, in effect, “cost to future economic growth,” or “cost to future GDP”. The problem with this is that GDP is a measure only of activity, not of wealth. If sea-levels rise by 5 feet, and many cities are partially submerged, trillions of dollars of net-wealth will be lost in uninhabitable homes and buildings, etc.. However, paradoxically, this can cause an increase in GDP, as there are sudden needs for construction, etc. Just because there is no cost in terms of future economic growth, doesn’t mean there is no cost!

    Still, Nordhaus never states what you claim he states, that global warming is not a crisis.

    His other article, on Agriculture, I personally found more persuasive. He points to weaknesses in assumptions some have made that have led them to conclude that warming will be disastruous for agricultural output (especially, as he observes, you cannot simply change climate variables without also assming farmers will take logical measures to adapt to those changes). Nonetheless, even if we assume he is right regarding agriculture, there are many other costs of GW that he makes no claim about.

    – Dan

  40. Jeffrey Davis:

    [Regarding the agricultural costs associated with GW]

    According to my crude understanding of GW, the more energy in the atmosphere, the greater the variability. Now, variability is a usually a wonderful thing, but not to farmers. The more this year is like last year, the better farmers like it. (Ordinarily.) Greater variability in rain fall, temps, humidities, what-have-you, even absent a disaster, isn’t necessarily a Good Thing. When we have to feed six billion of us, with petroleum products like fertilizers at a premium, we have scant leeway.

  41. Dan Allan:


    looks like our posts crossed in the email. if you send me a link to the mendelsohn article, i’d gladly take a look.

    By the way, if you accept Nordhaus’ conclusions:

    a) 700 billion to control global warming under Kyoto
    b) 75% of cost borne by the U.S (about 500 billion)
    c) Kyoto is 1/7 as efficient as a more ideal system

    One could infer that, using a more ideal system, we could prevent future warming at a cost of only about 80 billion to the U.S.!!!! less than we spend PER YEAR on Iraq!

  42. Alain Henry:

    About future costs of GW: I think a wider view (wider than just GDP or wealth) should be used to assess future costs GW. There are a number of things that cannot be evaluated properly. For example, GW will increase migrations and war/security risks. But what will be the cost of that ? (might be expensive, when you think of Iraq.)

    To put it in another way, what happens to the rest of the world will have an impact – and a cost – to the US and other industrialised countries. This is not usually included in impact evaluation, as it is very difficult to evaluate. Costs might thus be higher than what we can evaluate now.


  43. R Xapt:

    #89, Dan

    Thanx. I’m interested in what you climatologists think of the work being done by economists. Your comment on activity (flow) versus wealth (stock) is interesting. Of course, given that we’re talking about temperature rise over the next 100 years it’s likely that those living on coastal areas would have sufficient time to adapt in ways that would at least mitigate the loss in wealth.

    And a minor point (not worth arguing over), I don’t think I ever said Nordhaus claims that global warming is not a crisis. If I did, I misspoke. The consensus among economists (and many climatologists?) seems to be that we just don’t know.

    Below is a link to Mendelsohn’s website. As you can see, his publications are listed but none are PDFed. I take it that you have access to some of the journals he publishes in, so hope this helps. Again, I’m interested in what you folks think about the work being done by economists when it clearly spills over to your field….

  44. R Xapt:

    #91, Dan

    Yes, $80B is chump change in the world that is Washington, D.C. Of course, we won’t get there with the ‘energy bill’ that came out of the conference committee last night. Sheesh, more subsidies to oil companies [good for me b/c I own oil stocks], opening the producers of MTBE to the trial lawyers [bad for everyone except the lawyers], and more ethanol [great for large agri farmers]. I have read that more energy is used producing a gallon of ethanol than a gallon yields! If true, ethanol represents 1 step forward and 2 steps back.

  45. Lynn Vincentnathan:

    RE #94, that sounds right about ethanol using more fuel than it produces, because beyond fuel to run the farm equipment, you have to also figure in irrigation & the energy to pump the water, and the energy to produce tractors & farm equipment, & the shipping of metals to produce tractors, and destruction of rainforests to mine the bauxite to make the aluminum (more energy) used in the farm equipment, and the paperwork (& trees) involved, & production of pesticides, etc., etc…..

  46. Hank Roberts:

    All I can say is, it’s a darn good thing that weather and climate aren’t the same, and breaking records for temperature is _weather_. Eh?

    Today’s NY Times:
    The demand for electricity to run air-conditioners is expected to break records in the District of Columbia, Maryland and in parts of Virginia today, according to Pepco, the energy company that serves more than 725,000 customers in the three regions.

    Pepco – which broke its record for peak demand at 5 p.m. on Monday as customers used 6,452 megawatts of power – asked its customers to “use energy prudently” to help prevent “possible power supply problems.”

    The Emergency Management Agency in Washington, D.C., also issued an alert today asking everyone to turn off any computers and electric appliances that are not in use.

  47. Jeff Norman:


    I am curious about something in your July 24 post (#76 above). You said, “When economists can predict what the stock market will be like a year from now, maybe I’ll start gambling with it,”.

    I think that we could all agree that the global climate system is somewhat more complicated than the stock market.

    I also think that we could agree that thousands of (generally) intelligent people motivated by personal gain have modelled stock markets using all the best available technology and data for hundreds of years.

    If you are unwilling to put your faith in stock market forecasts for one year, are you willing to put your faith in global climate model forecasts of 50 and 100 years into the future, given that these models are based on incomplete data and limited resources?


  48. Michael Jankowski:


    I’m also confused as to how you (Lynn) are such a strong a proponent of long-term climate investing (and personally take such action) but an absolute opponent of long-term stock market investing (and personally do not take such action). There most certainly is a consensous that long-term investing should include stocks and that these stocks (properly diversified, such as in a mutual fund, or even an index fund that simply attempts to track the market) will make money as a whole over the long term – returns you cannot expect to get with savings accounts, bonds, annuities, etc. And historically, this has held true. I think there have only been a few periods where the US stock market has lost money over any 10-yr period.

    I would be very happy to discuss the items in #8 with you, but I think now it should be prid quo pro…you ask me questions as to why I’m “so resistant to GW studies,” and I’ll do the same with you regarding the stock market.

    I’ll provide an email address after someone tells me how I can list it here without becoming overwhelmed by spam (or a moderator could simply email it to you privately).

  49. Eli Rabett:

    Re #97, while the global climate system is complicated, we have a good grasp of the basic physical laws under which it operates. Amusingly, one of the strong limits on our ability to model the system is the lack of strongly reliable data from more than about 100-150 years ago against which various proposals can be tested.

    As someone (maybe one of the hosts of this blog) put it, who you gonna trust for climate data in 1800, the models or the measurements. There is no easy answer to that one which explains the importance of climate reconstructions and the efforts being put into improving them.

  50. Lynn Vincentnathan:

    RE #97, I think I’m consistent. It is prudent to abate GW (esp. with cost-effective measures) and reduce risks of its harms (though I am mainly concerned about reducing its harms to others), and it is prudent not to gamble. Now the truth is I am invested in mutuals and annuities, & increasingly so, partly BECAUSE OF ALL THE MONEY I’M SAVING FROM ABATING GW. But a financial expert did exclaim how conservative our investments are. Knowing the complexity of the ecosystem, and that scientists don’t have all the answers, it is just possible (& increasingly so) that we are headed for at least economic disaster (the economy being even more sensitive to disruption than total earth system).

    The other issue is what are we gambling with. GW is gambling with life; stocks are only gambling with money (which comes & goes & comes).

    Now, I understand that scientists are gambling with their reputations, so they must seek to avoid the false positive (GW is not happening when they claim it is), or no one will believe them again. I explained to my stat students that scientists don’t gamble, they need .05 significance, 95% certainty. One student always chimes in, “but I know a scientist who gambles.” I reply, “Yes, with money perhaps, but not with their reputation.”

    For people living in the world, we should be avoiding false negatives (behaving as if GW is not happening, when indeed it is). Why would we gamble with life? Play Russian roulette? Unless one is an Exxon CEO, it just doesn’t make sense.