Christy on global warming

Via David Appell, this statement from the American Geophysical Union confirming the reality of global warming. The statement says

that human activities — most notably the greenhouse gas emissions from power plants and other industries — are warming Earth’s climate at a faster rate than ever.

A particularly noteworthy signatory is John Christy. director of the University of Alabama’s Earth Systems Science Center. While noting that he is

“still a strong critic of scientists who make catastrophic predictions of huge increases in global temperatures and tremendous rises in sea levels.

Christy says

It is scientifically inconceivable that after changing forests into cities, turning millions of acres into farmland, putting massive quantities of soot and dust into the atmosphere and sending quantities of greenhouse gases into the air, that the natural course of climate change hasn’t been increased in the past century.

Christy’s statement, the strongest I’ve seen from him, is significant because he’s been one of the handful of reputable scientists whose work (on satellite measurements of temperatures in the upper atmosphere) and public statements have tended to support the denialist position that is propagated by the legion of “junk science” sites in the blogosphere. Over time, corrections to interpretation of the satellite data have produced a rising trend, similar to that found in measurements of temperature on the ground, rather than the declining trend reported in Christy’s early work.

That leaves Richard Lindzen as, to the best of my knowledge, the only reputable climate scientist still willing to say that the reality of human-caused global warming hasn’t been proved beyond reasonable doubt, and even Lindzen has been pretty quiet lately.

Of course, that’s not a problem for the global warming denialists. They don’t need reputable climate scientists to create the appearance of disagreement; they’re happy to accept the claims of anyone with a PhD after their name, or even without, as long as it supports their position. Currently their leading authorities on the recent history of the global climate are two astrophysicists (Baliunas and Soon), an economist (McKitrick) and a retired mining executive (McIntyre), but they’re happy to rely on astrologers if they give the right answer.

23 thoughts on “Christy on global warming

  1. John,

    I have seen similar from Christy five years ago. He was always upfront about the likelihood that change due to humans was happening. As I understand it, his main problem was that the data he was interpeting did not show the trend as predicted by models. If the trend is now larger it would be interesting. I will check today.

    I suppose I should point out that it is possible to say that a) humans must be changing the climate, and b) but not by very much.


  2. The satellite analysts all got together recently ( and discussed why there is a trend in the analyses away from the UAH data analysis and more toward what is found in the surface obs.

    BTW – UAH were the only ones for a while analyzing the data; once others got ahold of the dataset, they began to find errors in analysis [this is in no way similar to the McKitrick mendacity, since all the analyzers are not amateurs].


  3. John, surely you’re not suggesting that the views of an economist (about the global warming question) are irrelevant! Or are you?

    It is interesting that it seems just possible that some more rational debate might be forthcoming on the question of GW.

    After all, as I mentioned in another thread here, the NASA site seems to be suggesting, through recent reports, that 25% of the measured warming (unprecedented or not) may well be attributable to the sun’s activity and another 25% to soot affecting the albedo of the planet.

    Since they also seem to be settling on temperature increase estimates at the lower end of the IPCC published figures the inference appears to be that the CO2 effect is far less than they might have feared although, absent volcanic eruptions and other natural phenomena, mankind’s gas and particle output may be having an influence. But if, for the sake of the example, we accept that 50% of the possible increase is attributable to CO2/GHG and 25% to soot (both of which we might accept as human influenced, even if that in part simply means setting fires to burn forests), presumably the economics of the previously proposed solutions will need to be reconsidered?

    The net influence of GHG’s (of which only CO2 seems to be significantly controllable?) seems to be half the original estimate. Perhaps we should look at the soot question, since that is probably something we can address – though with different solutions to the CO2 problem, There is probably not much that we can do about the Sun.

    By the way, I am not so sure that total reliance on ‘experts’ is always the best way to progress. There are many examples, in science, where people who are inexpert have provided enormous insight or even complete answers to problems of understanding. In problem solving, consensus (or balancing the answers from the individual MEASURED experiences of a number of specialists) can be very useful to inform decision making. but consensus based on recorded and referenced measurements is very different from consensus based on modelled future predictions.

    There is no science in consensus. Only politics or, if the need for an answer based on previous experience is paramount, pragmatism.


  4. There are plenty of economic issues related to global warming, and I’ve written on some of them.

    On the general point about experts, it’s true in general that the race is not always to the swift nor the battle to the strong, but that’s still the way you should bet.

    In this particular case, it’s clear that most of the denialists are not merely non-experts but have a financial or ideological axe to grind.

  5. JQ- “There are plenty of economic issues related to global warming, and I’ve written on some of them.”

    But you don’t comment on their relevance.

    JQ -“On the general point about experts, it’s true in general that the race is not always to the swift nor the battle to the strong, but that’s still the way you should bet.”

    I never gamble. The bookie or slot machine always wins.

    JQ – “In this particular case, it’s clear that most of the denialists are not merely non-experts but have a financial or ideological axe to grind.”

    I have to say I have not really noticed that or perhaps I cannot see the financial axe. But that said, surely there must be financial axes throughout the extremes of the debate. Presumably the people in the middle are never heard because they never get enough funding to have a voice.

    As for the ideological axe. A faith in forecasts of the future, a notoriously unreliable methodology throughout recorded history, seems a lot more related to your earlier quip about astrologers than any connection from astrology to denialists.

    Why would a non-expert ‘acceptors’ opinion be of any more validity than a non-expert denialists?

    In fact, given how little even those close to the research know about climatic events (as evidenced by the perpetual calls for more funds for research and the few researchers/reporters who qualify their work with cautious caveats about ‘not fully understood’), it might be reasonable to suggest there are NO experts in the field. But there may be a few people who have spent more times than most looking at some of the evidence available to them. And a whole lot who see a funding bandwagon of almost unparalleled opportunity.

    But the vast majority of people who ‘know’ that global warming is happening have absolutely no personal knowledge at all. They simply repeat the words with which they have been indoctrinated.

    Informal classical training really.

    “Repeat after me …”

    Ah well, so much for new educational methods supposedly teaching people to think for themselves. That would be the last thing that any serious authority would want. Hence the rush to gain ideological control over all forms of education. Once achieved people will be suggestible to anything. Of course various organizations, many religious, have followed that route over the millenia. Little agreement seen so far. No doubt GW will prove to be an equally diversionary play.


  6. Grant, you miss the main point. The number of expert denialists can literally be counted on one hand. Or even one finger.

    That you are forced to rely upon the work of James Hansen is pretty telling. Your earlier post, badly misinterprets his work. While he has put forward arguments for future GHG emissions to be lower than projected by the modelers, he also puts forward arguments that the dangers of global warming have been underestimated. He is also publicly scathing about the quality of arguments put forward by the skeptics.

    Before you suggest that “vast majority of people who ‘know’ that global warming is happening have absolutely no personal knowledge at all. They simply repeat the words with which they have been indoctrinated”, you should perhaps, take a long hard look in the mirror.

  7. Cherry-picking Hansen may be among the latest in denialist agitprop tactics (as Ken no doubt knows), as I see the phenomenon occurring elsewhere recently.

    I suggest reading Hansen’s actual work and seeing for oneself whether he thinks there is only a small anthropogenic component to climate change, soot, sun, etc etc.

    One may read his scientific work here (note the transparency):

    Nothing there about ocean heat storage. One would need a subscription to, say, Science for that. If Grant has a subscription I’d be happy to provide some citations for further edification.


  8. John –

    In case you didn’t already know, your “Its true the race is not always to the swift …” line is lifted from Damon Runyon (in turn parodying Ecclesiastes).

    I used to be a greenhouse sceptic myself, but the weight of evidence that the earth is warming at a rate that is unlikely to be wholly natural has become much greater in recent years.

    Mind you, I think the modelling efforts to date have been so unconvincing that we must all be missing one or more factors that are at work here. Consequently we should treat estimates of how long and how rapidly the earth will warm in future with caution – which makes the policy questions really hard. Simple-minded application of the “precautionary principle” is not an adequate answer.

    Also, FWIW I think Christy’s stated reasons for capitulation to the believers is a poor one. It is not “inconceivable” that industrial activity has had only minimal effect on the earth’s climate. I was taught about the earth’s ‘automatic stabilisers’ (to borrow a term from macroeconomics) before it was dressed up as the Gaia hypothesis (and subsequently much misunderstood by mystical greenies), and back when people feared global cooling.

    Prominent amongst these stabilisers is the oceans’ buffering of changes in CO2 concentrations (more CO2 in the air leads to warmer climate leads to more absorption of CO2 in water) – the numbers here are so large that they dwarf man’s pitiful CO2 output. Obviously this hasn’t worked – can anyone explain to me why?

  9. DD, I sort of knew it was a quote, and I’ve certainly read Damon Runyon, so thanks for nailing it down.

  10. Ken,

    I think it is you who have missed my point.

    In a chaotic and non-linear system the very concept of an ‘expert’ is questionable in my opinion. And there are many areas of ‘expertise’ that could and should have an opinion that may be on the fringes of or indeed outside the climate change industry. 4.2 billion US dollars estimated to be available for research grants in 2004 that I read about somewhere. Well, if it was my area of specialisation I think I would want to toe the line on that and hide any doubts I may have.

    Not really forced to rely on Hansen (and I have (briefly) read the pieces on the GISS web site), but you pointed to his work in the first instance so I was merely responding using the same reference point. Of course one is entitled to read the contents according to ones preferences. Personally I try to look for the overall balance of the pieces and see if anything leads towards a centre ground in any way. Or at least narrows the gulf between the opposing positions.

    As for your final comment, I’m not sure who YOU think of when you read ‘the vast majority’ but I am thinking of the average person in the street who believes the world as presented by media headlines without thinking about it much at all. Certainly without doing any significant reading around the subject. I was one of them until a couple of years ago.


    Re: cherry-picking Hansen. See my comments above. I have no desire or expertise to attempt a complete rationale and report of the all the climate change issues. Nor would this be an appropriate place to do so as I am sure JQ would agree based on previous comments.

    What I fail to understand is why my simple observations regarding some of Hansen’s recent papers, offered in response to a post about Hansen citing an earlier paper, should elicit your response. I don’t see how responding on a specific subject can be ‘cherry picking’. Would you also level such criticism at JQ for his comments on Christy that that initiated this thread?

    But then perhaps you are familiar with such tactics in a way that I am not. I assume this since I don’t remember reading ‘agitprop’ in any articles for the last 30 years. How very quaint. How very political of vocabulary.

    I did read through the recent articles highlighted on the NASA site. Hence my earlier comments. My inexpert understanding interprets what is reported as I mentioned above. Hansen believes, from his research, that the warming is real, that the likely effect is towards the lower end of the range of numbers bandied around in the late 1990’s (but even that may produce a worse situation than people imagine). Approximately 25% of the increase may be due to solar activity and therefore cannot be controlled. The remaining 75% is probably anthropogenic with perhaps 25% of that being soot related by causing a change in the planet’s albedo, very noticeable at certain locations. Therefore the implication is that the effect of CO2 in the mix may be less than originally proposed.

    My observation was that a response to this based solely on an expensive-to-implement CO2-control-only solution might be less that successful in several ways. My personal position on the issue of climate change is irrelevant to this observation.

    As for ocean heat storage, I have read something of that but I’m not sure what relevance that has to this particular thread. If you are suggesting that Hansen is incomplete since he doesn’t cover the subject (is that what you are saying?) it may have some relevance to general observations about the interpretation of Hansen’s work and provide an argument that Hansen underestimates the effects. But that is a different subject.

    JQ started the thread by observing that some people have interpreted John Christy as moving closer to embracing the arguments FOR global warming. Hansen appears to have varied his earlier observations following additional analysis of other effects. Perhaps between them they are simply doing what scientists do following research performed over a sensible period of time for the subject at hand. I think it would be excellent if we could eliminate the extremes of both views and start to work with some better, more refined information. At that point the politicians and economists may have some chance of doing a real assessment of cause and effect and of coming up with a well considered and pragmatic approach to managing as much of whatever the problem is as can be made possible.

    On the other hand I have little faith in politics as a medium for ‘solving’ anything, though it can produce changes of which many are unanticipated by the policy that spawned them, so I would settle for simply making less of a mess of things.

  11. I think the words of Michael Chricton were timely:

    “I want to pause here and talk about this notion of consensus, and the rise of what has been called consensus science. I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you’re being had. ”

    I also notice that JQ is still in the habit of attacking people’s qualifications. Not suprising really. He called me a pharmacologist when I am nothing of the sort!

  12. Derrida Derider writes:

    “Prominent amongst these stabilisers is the oceans’ buffering of changes in CO2 concentrations (more CO2 in the air leads to warmer climate leads to more absorption of CO2 in water) – the numbers here are so large that they dwarf man’s pitiful CO2 output. Obviously this hasn’t worked – can anyone explain to me why?”

    Well, to lowest order in everything this is a *positive* feedback, because CO2 becomes less soluble as the water gets warmer. But the whole air-sea exchange problem is a lot more complicated than that, involving multiple equilibria among CO2/bicarbonate/carbonate ions, deposition of solid carbonates, and nonquilibrium effects like wind speed, exchange of water between surface and deep layers, etc.

    Remarkably, this horribly complicated exercise in coupled ionic equilibria turned out to be one of the foundation stones of the modern theory of global warming. Up until the late 1950’s, it was generally believed that the oceans would easily suck up nearly all anthropogenic CO2. Then Suess determined, from isotope measurements, that fossil fuel CO2 was showing up in the atmosphere, and Revelle and Suess crunched some numbers and found that the appetite of the ocean surface layers for CO2 was a lot smaller than everyone had guessed.

    Anyone interested in this subject ought to read Spencer Weart’s beautiful little book, _The Discovery of Global Warming_ (Harvard University Press 2003.) And read his web site,, which contains an extensive collection of supporting information.

  13. Scientific models aren’t evidence, they are a particular way of organising scientific hypotheses. Like other scientific hypotheses they can be confirmed or refuted by empirical evidence. This is rarely a once-and-for-all process, as hypotheses, including models, are adjusted in the light of new evidence.

    If the evidence is inconsistent with core assumptions of a model (or core hypotheses of a scientific research program) this process of adjustment will eventually fail, forcing the advocates of the hypotheses either to abandon it or to make more and more extreme efforts to “save the phenomena”.

    We are seeing this process in relation to set of negative hypotheses about climate change that support policy inaction. Ten years ago, it was reasonable to say that there was no clear upward trend in global temperatures and that to the extent that some upward trend was apparent, it was unclear whether this trend was anthropogenic. The combination of new data (a string of very warm years), improved historical data and improved models has rendered these positions untenable.

    The economic case in favor of taking action is similarly being strengthened by analysis of relatively low-cost methods of reducing emissions and by more careful consideration of issues related to discounting.

  14. Another thing:

    “I also notice that JQ is still in the habit of attacking people’s qualifications.”

    Yes, JQ, shame. Such actions, in this context, disallow the expertise of, say, an astrologer or other such unqualified amateur to opine wisely on climate change.

    IOW, without unqualified people questioning climate change science, the denialist crowd cannot opine, and JQ will have silenced these important voices in the debate.


  15. Dano,

    “Astrologers” are a red herring and you know it.

    JQ attacked me by claiming that I’m a pharmacologist (thereby implying that I shouldn’t be debating the matter).

    Note that I have never said that we shouldn’t listen to JQ because he is an economist, not a climate scientist. As I have said, any particular contribution to the debate should be criticized based on its merits, not who wrote it. If you have a problem with that Dano, please say so.

  16. Ken,

    Let me put my thoughts on models in terms that you can understand.

    Computer models are great for generating hypotheses and helping one think about the issue at hand. But they are not in themselves evidence for anything. I use molecular dynamics models to help understand the functions of macromolecules. But the results of those simulations are not “scientific data”.

    The problem is that the climate models are beeing represented as data. This is very wrong, IMHO.

    Here, the words of Chrichton ring true:

    “But now, large-scale computer models are seen as generating data in themselves. No longer are models judged by how well they reproduce data from the real world-increasingly, models provide the data. As if they were themselves a reality. And indeed they are, when we are projecting forward. There can be no observational data about the year 2100. There are only model runs. ”

    Do you believe in modelling as a source of data, Ken? I don’t, and I use modelling myself.

  17. THanks, Robert – I’ll certainly chase up that link (I’m trying to remember some of this stuff from the early 70s, so its maybe not surprising I got things arse-about).

    Aaron, of course models are sources of prediction, not data. Mind you, there are plenty of times when you have to use predictions as data because there ain’t no data (the whole point of forecasting is that its in the future and, absent time travel, we don’t have data from the future). But if someone has been pretending their model output is ‘proof’ of global warming then indeed they have been naughty.

    It’s not the models that should make you accept anthrogenic global warming – it’s (as John pointed out) the huge amount of hard data on this we’ve accumulated in the last ten years. And it is reasonable to predict that if our activities have made earth warmer in the past, and we are still carrying on these activities, then the earth is gunna be warmer in the future. To predict how much warmer, and how much cessation of activity we’d have to do to slow or stop it, is highly uncertain though in the absence of a good understanding of all the relavant mechanisms (the models simply embody our understanding).

    I think step one on this issue is to spend lots of money on getting that good understanding. In the meanwhile, we should be wary of radical proposals.

  18. Aaron wrote:

    “Astrologers” are a red herring and you know it.

    Well, I was just keeping questionable science in your half of the planet. I’m sure you can appreciate the fact that Daly uses an astrologer [as opposed to trained climate scientists ] to back his touts.

    Note that I have never said that we shouldn’t listen to JQ because he is an economist, not a climate scientist. As I have said, any particular contribution to the debate should be criticized based on its merits, not who wrote it. If you have a problem with that Dano, please say so.

    If you mean it’s OK to use JQs opinion to back your claim, I don’t have a problem with that.

    I have a problem with using amateurs for touts in general when the amateur is cited as authority. I don’t think anybody arguing for climate change would cite JQ as an authority. Just as no one would use, say, the touts on Bizarre Science as evidence to back a claim.

    Now, the other side of the coin is the 5 guys who are skeptics [sceptics] who have actual training in climate science who are cited as authorites…you haven’t addressed that and how we deal with it.


  19. Why We Shouldn’t Sweat Global Warming

    In a briefing for congressional staff and media on November 5, sponsored by the Cooler Heads Coalition, Dr. Patrick Michaels debunked many of the global warming myths that have made their way into public debate over the last decade. Climate models have consistently overestimated climatic warming, and new research has proved that mild warming will likely be beneficial to human beings and the planet, according to Dr. Michaels, Professor of Environmental Science at the University of Virginia

    ‘The warming we are seeing is largely confined to the areas of Siberia and northwestern North America, and the vast majority of that occurs during the winter months,’ Dr. Michaels explained. Accordingly, the most likely result of a predicted 1.5-degree increase in temperatures over the next 100 years will be slightly milder winters in Siberia and Northern Canada, hardly doomsday effects.

    The current, rather mild, warming projections come from many of the same researchers that made the apocalyptic warming predictions of a decade ago. Climatologists around the world have been progressively revising their predictions downward as their models improve. ‘It appears that the people who were the so-called ‘small band of skeptics’ must have had a point,’ Dr. Michaels commented.

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