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Review of Spencer’s ‘Great Global Warming Blunder’

Filed under: — group @ 28 April 2011

Guest commentary from Steve Ghan

A good writer knows their audience, and Roy Spencer knows his. There are plenty of people who would love to hear a compelling argument for why no action is needed to mitigate global warming, and Spencer’s book “The Great Global Warming Blunder: How Mother Nature Fooled the World’s Top Climate Scientists” will give uncritical readers the argument they’ve been looking for. As Sarah Palin said, “while we recognize the occurrence of these natural, cyclical environmental trends, we can’t say with assurance that man’s activities cause weather change”. That is really the essence of Roy’s argument.

What is the Great Blunder? According to his book, “a fundamental mistake has been made in previous interpretations of satellite data”…”a mix-up between cause and effect when analyzing cloud and temperature variations”.

Who made this mistake? Invariably, it is “the IPCC researchers”. He cites a couple of specific papers by Piers Forster, but finds no fault with them. So he casts aspersions into the wind.

Spencer’s assertion in his book of that there has been a “mix-up between cause and effect” is quite a different conclusion from his recent article published in the Journal of Geophysical Research – Atmospheres in 2010, which concluded innocuously that “since the climate system is never in equilibrium, feedbacks in the climate system cannot be diagnosed from differences between equilibrium climate states” … despite the fact that this is the exact diagnosis supporting his conclusion in the book.

In his book Spencer contends that short-term fluctuations in the energy balance and surface temperature are consistent with a low climate sensitivity: “A careful examination of the satellite data suggests that manmade warming due to a doubling of atmospheric carbon dioxide could be less than 1ºC – possibly much less.”

Why does Spencer consider his “discovery” of a mix-up between cause and effect to be so important? Because “natural cloud fluctuations in the climate system will cause a bias in the diagnosed feedback in the direction of positive feedback”, which means those careless IPCC researchers have vastly overestimated the climate sensitivity. He then asserts that “if the real climate system looks sensitive to climate modelers, they will build their models to be sensitive also.” But he never mentions the fact that climate models have produced climate sensitivities of 2-5ºC per doubling of CO2 concentration for decades, well before the Forster papers and before satellite measurements were available for those careless anonymous IPCC researchers to produce biased estimates of climate sensitivity.

Moreover, how could models explain the observed warming during the 20th century if the climate sensitivity is as low as it is, unless aerosols don’t cool and there is some other warming mechanism? Spencer addresses this question with a hypothesis that natural cloud variability is the cause of longer term trends. He proposes a relationship between the Pacific Decadal Oscillation (PDO) and clouds by considering a variety of combinations of initial ocean temperature, ocean thickness, cloud feedback, and forcing by clouds (neglecting forcing by CO2 and the water vapor feedback entirely) in a simple energy balance model, and finds a relationship between PDO and clouds using 9 years of satellite data. By exploring parameter space randomly he found the agreement with the observed 20th century warming was best for an initial ocean temperature 0.6ºC below normal, which means almost all of the warming that his model explains is simply the ocean returning to normal, not the response to decadal variability in clouds. (Ed: note that the details of this calculation are heavily criticised by Barry Bickmore in a series of posts). Of course, decadal variability in clouds can only be a response to decadal variability in the surface conditions or atmospheric circulation that drive cloud formation, because the lifetime of cloud systems is days rather than decades.

How, then, does Spencer explain the ice ages? He essentially punts, saying he believes the ice core record is “irrelevant”, that “we don’t have a clue” what was causing those climate variations. But if climate really is as insensitive as he claims it to be, the climate forcing producing the ice ages must have been huge, much larger than the radiative forcing from orbital changes, surface albedo, and greenhouse gases. He claims to prefer empiricism to theoretical models, yet when the paleo data supports the higher climate sensitivity simulated by climate models, he blames some unknown mechanism. It reminds one of the old cartoon of the physicist drawing mathematical theories madly on the blackboard, completing his theory with the statement “and then a miracle occurred”.

Spencer does make a valid point about the potential for bias toward exaggerating problems because it can bring in more funding. We all must be wary of this. On the other hand, it’s worth noting that the book market tends to financially reward a bias toward contrarianism.

But for me his credibility as a climate scientist was most compromised with his assertion that “it would take only one research study to cause the global warming house of cards to collapse.” So much for weighing the evidence. As Arnold Schwarzenegger said about the diversity of views of climate scientists, if your child is ill and 98 out of 100 doctors call for life-saving surgery and 2 say it is not necessary, your decision is obvious.

Roy Spencer is respected for his remote sensing expertise, but the conclusions of his book are nothing like those in his JGR article. What a difference an audience can make.

Suspension of comments: Due to Roy Spencer being caught up in a loss of power related to the tornado outbreak in Alabama, we are suspending comments on this post until he is in a position to respond (should he choose to).

Update (05/05/11): Comments have been re-opened.

69 Responses to “Review of Spencer’s ‘Great Global Warming Blunder’”

  1. 1
    Tuomas says:

    “How, then, does Spencer explain the ice ages? He essentially punts, saying he believes the ice core record is “irrelevant”, that “we don’t have a clue” what was causing those climate variations.”

    It might be difficult for a person to give weight on any empirical evidence describing climatic conditions of some pre-historic era, if the person in question doesn’t believe that our Earth even existed that far back in time. I’d be very surprised if someone with such world view would consider the pre-historic proxy data somehow relevant in his/her understanding of the evolution of our climate system.

  2. 2
    Deen says:

    Spencer does make a valid point about the potential for bias toward exaggerating problems because it can bring in more funding. We all must be wary of this.

    Haven’t there been quite a few cases already where scientists have been so wary, that they’ve severely underestimated their predictions?

  3. 3
    Buck Smith says:

    AS I understand Spencer’s arguments he does not say that “man’s activities cause weather change” What he says is that CO2 and other greenhouse gas driven warming is likely to be attenuated not amplified by the effects of water vapor and clouds. I think he also makes the point that as measure and model the change in climate caused by greenhouse gas, natural variation is occurring. So that must be taken into account. I read about a paper of his that showed the effect of irrigation on the temperatures in the Central Valley of California.

    [Response: Nobody disputes that natural variations are also occurring. Nor that there are other drivers of climate change. However, it doesn’t follow that just because these things are also going on that climate sensitivity is small. The evidence for a significant climate sensitivity (i.e. > 2ºC) exists and is not affected by anything Spencer has said. – gavin]

  4. 4
    adelady says:

    “it would take only one research study to cause the global warming house of cards to collapse.” is the killer comment for me.

    Suggesting that “global warming” is a collapsible house of cards is a loser on several counts. For starters, the science is that of climate generally. “Global warming” is not a discrete entity or theory. It is a mere subset of general climate theory. If we weren’t adding ghgs to the oceans and the atmosphere at the rate we are, that selfsame science would be devoted to calculating and explaining how, why and where things should cool down in accordance with our current inter-glacial status.

    And the house of cards notion is just silly. All science works much more like jigsaw puzzles than card houses or toddlers’ stacks of blocks. Even radically new notions like Einstein’s relativity or Warren & Marshall’s ulcer treatment or plate tectonics didn’t abolish everything previously known about physics or physiology or the continents. Just better explanations filling in gaps – and that’s where climate science is now.

    There will be astonishing discoveries and better explanations. But they won’t change facts. Plate tectonics didn’t eliminate everyone’s observations that the continents appeared to fit each other despite the great distances – it explains that appearance with a mechanism, which just happens to explain a whole heap of other things. (Including some things about geological release and absorption of CO2.)

  5. 5
    Dan H. says:


    I know of very few cases of scientists underestimating predictions. Many of the overestimates by 2100 include 2-4C of warming (current trend is 0.6C/century), 20 feet of sea level rise (~3mm/yr is current), disappearance of Arctic sea ice by …. (insert favorite year here. I know of very few predictions which are less than the current trends. Those that overestimate have done climate science a great disservice as people tend to disbelieve other predictions also. Witness the IPCC and Himalayan glaciers.

  6. 6
    greyfox says:

    Mr. Spencer lost credibility as a scientist long ago…a proponent of ‘intelligent design’ aka: creationism…contributor to the Heartland Institute and Geo. Marshall Institute…both shills for the petroleum industry et al…and on and on. He may have expertise in a narrow topi range, but has clearly fled into the camp of the religious right and the fossil fuel corporate agenda. I’m not sure why we are even talking about him, other than he will be quoted by the Limbaugh’s of the world.
    I despair that humans will get past this kind of fellow’s nonsense fast enough to do any serious repair to our world. Perhaps that is his goal?

  7. 7
    Bryson Brown says:

    It’s very interesting to me, how people like Spencer combine professional competence on a specific topic with complete incompetence and arrogant disregard for the expertise of others on wider issues. You can’t learn to do good work without listening to the people training you. But somehow the ability to respond to evidence and instruction in one area (at least during training) just doesn’t transfer to others. Cheap skeptical maneuvers (it’s all about empirical evidence except when it isn’t) are a dime a dozen, and they take the same general form regardless of the field you apply them to. You would think people who actually do learn how to do good work in one area would recognize and avoid them elsewhere. But (on the evidence) you’d be wrong…

  8. 8
    Bryson Brown says:

    Dan H: That’s a pretty sorry bit of exageration on your part. Why would current trend be the conclusive basis for rejecting a 2-4 degree increase by 2100, when GHG emissions continue to accelerate? And where did you get the 20 feet of sea level rise ‘prediction’? The predictions I see out there range up to 2 meters (that’s about 1/3 your number), though more would be unavoidably ‘in the pipeline’ if we don’t stabilize GHG levels well before then. As for the Himalayan glaciers, that was a simple mistake, not a serious but failed prediction– and the threat to the glaciers is real, even if the timeline is longer.

  9. 9
    Nick B says:

    Dan H.

    The himalayan glacier figure (2035) was a typo not an overestimate and it was one error in the roughly 3000 page technical document and NOT in any of the summaries. I’m 100% certain that you did not come across this error in your readings.

    Sea level rise is actually a perfect example of a significant underestimate by the IPCC. Two others are the rate of emissions (higher than predicted) and arctic ice melt (faster than predicted.) I’m sure the more enlightened here can share many more.

    Your use of current trends ignores that these changes are likely to be accelerating. (The basis for my conviction that you have not read very much IPCC literature)

    Those that publish peer-reviewed papers on the subject do a great service to climate science and the public welfare if you care to listen.


  10. 10
    Rod B says:

    Tuomas, clever (really) and probably on topic, but mis-characterizes Spencer’s beliefs.

  11. 11
    JCH says:

    Dan H – can you refer me to a scientific paper where there is a prediction of 20 feet of SLR by 2100.

  12. 12

    Excellent review and criticism… right up until:

    “Spencer does make a valid point about the potential for bias toward exaggerating problems because it can bring in more funding. We all must be wary of this”

    Mention of “potential” is not the same as showing a bias. Spencer is just providing the doubletalk pablum that suffices for the denial cheerleading he offers.

    A better criticism is that climate science has been too quiet, too reticent in speaking out. Given the well-stated risks and the clear science – it seems that funding is radically low. Stupidly low. Funding has been reduced, programs cut, graduate programs eliminated. This is dangerous stupidity that we tolerate. And it is beyond risk. It is blunder

  13. 13
    Nick Barnes says:

    Following on from Barry Bickmore’s posts, these two by Arthur Shumway Smith completely annihilate anything remaining of Spencer’s “model”. It turns out to be fully (and easily) integrable to an analytical solution with plenty of free variables: any competent undergraduate in applied mathematics could derive it in ten minutes.

    Mathematical analysis of Roy Spencer’s climate model
    Roy Spencer’s six trillion degree warming

    The essence of the solution is that T is an exponential return to a equilibrium (which varies over time according to a smoothed PDOI) from some other value. The initial value, the exponential time constant, the equilibrium value, and the PDOI smoothing and variation are all governed by independent free variables. Unsurprisingly, if he sets the equilibrium to current temperatures, the initial value to 1880 temperatures, and chooses the exponential time constant and the PDOI parameters, he can get a good fit to temperatures since 1880, and finds that it projects constant future temperatures (because the exponential vanishes). Of course (a) extending backwards past 1880 breaks very fast indeed, and (b) this shows that the model is totally non-physical.

  14. 14
    rv says:

    The subtitle of Spencers book reminds me of some sort of creationists:

    Only misguided researchers take the fossiles as a proof for evolution.
    In fact these silly scientists are fooled by the nature (i.e. by God ore the devil).

  15. 15
    SecularAnimist says:

    Dan H wrote: “I know of very few cases of scientists underestimating predictions.”

    With all due respect, as your comments on this site have consistently demonstrated, what you don’t know about climate science could fill a book.

  16. 16
    ghost says:

    Dan 5 “I know of very few cases of scientists underestimating predictions.” Well, it seems to me that you just read one right here. That is, if you read Steve’s commentary, and if we treat what Spencer-For-Hire says in his popular writing as estimation/prediction. If I read Steve’s material correctly, I suppose a person can disregard his book, rely on his paper, and say he is in the consensus; or rely on his book and say he is in the underestimation game. It really can’t be both, can it?

  17. 17
    Ray Ladbury says:

    Perhaps the title is self-referential?

  18. 18
    Didactylos says:

    Dan H, nice troll. We almost didn’t notice that you jumped from already established under-estimates in past projections to future projections that you consider to be too high (for no reason that you can argue).

    How can it be an over-estimate until you know whether it’s over or not?

  19. 19
    Ray Ladbury says:

    Dan H. says, “I know of very few cases of scientists underestimating predictions.”

    Dan, I hope you can forgive us if we decide not to base our conception of reality on what you do or do not know.

  20. 20
    Pete Wirfs says:

    I think Dan H has a valid point that over-estimations could be problematic.

    However I also believe that many of the perceived over-estimations are misinterpretations of what people have actually said.

    “If A happens then B will happen”. This statement does not predict that B will happen, but when it fits ones political agenda, they will claim that it is a prediction.

  21. 21

    No one even noticed Dan H.’s most egregious cherry pick, using 0.6˚C warming per century by counting from (I’m guessing) 1910 to 2010, rather than restricting his trend to the actual AGW influenced period from 1979-2010.

  22. 22
    John E. Pearson says:

    20 Bob Said about not noticing egregious cherry picks:

    There are those of us who cherry pick who we read. I never read anything that guy says because I long ago concluded that he was driven by a political rather than a scientific agenda.

  23. 23

    #1, #10–

    Just for the record, RodB is right; as I understand it, Dr. Spencer is not a “young earth Creationist” but a proponent of “Intelligent Design.”

    Someone adopting the latter position takes seriously the evidence of paleontology, and so Dr. Spencer does–though not seriously enough, it seems.

  24. 24
    Pete Dunkelberg says:

    Typo: “Spencer’s assertion in his book of that there has been….”

  25. 25
    Pete Dunkelberg says:

    Kevin McKinney, so Spencer is an IDC (ref?). IDC’s can easily be YEC’s in the bargain. In any case they believe in magic. Does not Spencer believe that God will not allow us to ruin His climate?

  26. 26
    gavin says:

    Coincidentally, Roy Spencer is in the middle of the tornado outbreak that has hit Alabama. Obviously, we hope that he and everyone else affected stay safe.

  27. 27
    One Anonymous Bloke says:

    Kevin McKinney #23 You might as well say “He doesn’t believe in the tooth fairy, just the bogey man.” It drives me nuts that this man can be financially rewarded for saying things that would land him in prison if he declared them under oath. Time for another audit of bookstore shelves – this one belongs in “Fiction” or perhaps “Spirituality”.

  28. 28
    Susan Anderson says:

    I do wish you all would not spend quite so much energy on obvious trolls. Maybe one or two cogent informational responses, not a swarm?

    These discussions are normally full of nourishment, and despite my fascination with delusionalism, it palls and distracts.

  29. 29
    Patrick Kelly says:

    On the other hand, it’s worth noting that the book market tends to financially reward a bias toward contrarianism.

    This essentially irrelevant and misleading comment is typical of what is a very lazy review. Just another snide dig. Certainly in this part of the world it is virtually impossible to purchase works with an anti-AGW perspective. Mainstream booksellers just don’t keep them. One needs to get on line to find available offerings. One has to know what one is looking for and know where to look. The general public gets very little information about genuine shortcomings in the IPCC line and IPCC interpretations are prominently and repeatedly pushed in MSM outlets.

    [Response: Sure, Plimer’s book didn’t get any Australian media coverage, and I’m sure no-one could find it in bookstores… – gavin]

    Meanwhile Sphaerica(Bob)(#21) refers to “the actual AGW influenced period from 1979-2010.” One might ask why current and recent climate trends aren’t more often analysed in the context of the current cycle, say, 1680 to 2010. Doesn’t suit the narrative, I guess.

  30. 30
    One Anonymous Bloke says:

    #29 If no-one looks at the long-term data, how do you know this “cycle” of which you speak exists? *cough* paleoclimatology *cough*

  31. 31
    Bill says:

    Not sure why this thread is very topical now. I read the book sometime last year and found it unremarkable. Why waste time discussing it now, or did I miss something?

  32. 32
    CharlieT says:

    So Roy Spencer’s suggestion is that cloud cover changes may drive climate rather than respond to it. -Looking at the Global monthly cloud cover changes since 1983, for example as shown in
    It doesnt seem unreasonable to wonder whether this might be the case, if clouds represent a -18 watt/m2 forcing on average and there was a 5% change in cover, that might lead to a 1.5 Watt/m2 change.
    I understand that ISCCP do a much better calculation, so it would be helpfull to see a plot of their estimates of the change, to understand the effect.
    If the counter argument is that these changes are a response to Global Warming -it would be really good to see a graph showing what the models predicted / hindcast on average for the global cloud cover.

    I am sure that these graphs must exist somewhere , but I havent found them.
    Can you help? Thanks

  33. 33
    Titus says:

    Susan Anderson says:
    “I do wish you all would not spend quite so much energy on obvious trolls. Maybe one or two cogent informational responses, not a swarm?”

    Of interest would be if we analyze why this happens.

    Maybe an open raw nerve has been touched which has created a disturbance in the force initiating an auto response?

    Anything else?

  34. 34
    Steeptown says:

    It’s great news that Spencer, one of the world’s top climate scientists, is alive and well. There are few scientists who understand atmospheric physics like he does.

    [ now now, be nice. – moderator]

  35. 35

    Dan H #5: here’s a big underestimate. Before we had GRACE satellite measurements, the consensus was that the Antarctic would be in mass balance for a long time, with increased iceberg calving offset by increased snowfall in the interior. Wrong. It turns out that the Antarctic is losing ice mass fast.

    Charlie T #32: if cloud changes drive climate, what drives cloud changes? Or is it turtles all the way down?

    I wonder how much value there is in taking people like Spencer on head-on. I’d rather try to get the science into an accessible form, so the average person can take this on themselves. One of my big problems has been that the basic theory is not all explained clearly for the uninitiated in one place. Raypierre’s Principles of Planetary Climate is a big step in that direction, though it is aimed at the scientifically literate.

    I’m aiming when I have the time to post my (I hope) more accessible understandings on my blog every now and then, such as this one on greenhouse spectra. However, it would be even better if people more qualified to do so wrote those articles and posted them somewhere with a high readership, like this site. What I would like to see is a primer somewhere between the materials at the Start here page and a textbook treatment (correction on the Start here page: the Pew Center link is broken; it should be

  36. 36
    Nick Gotts says:

    “Dr. Spencer is not a “young earth Creationist” but a proponent of “Intelligent Design.”

    Someone adopting the latter position takes seriously the evidence of paleontology” – Kevin McKinney

    No, not at all. The evidence of palaeontology is completely incompatible with “Intelligent Design”, as soon as the latter is given any real content: the evidence shows clearly that evolution does not have the appearance of a planned or directed process. “Intelligent Design” also ignores the mass of evidence from genetics, biogeography, developmental biology and other disciplines. It is, in fact, pure fraud: it was created simply in an attempt to get round American restrictions on bringing religion into public school science classrooms. Google “cdesign proponentsists” on the latter point. Spencer’s support for this dishonest nonsense is indicative of how far he can be trusted on climate issues.

  37. 37
    Kiwpy says:

    The days are not far what we don’t expect. Ice poles, sea levels, Himalayan etc all are now threatening us. This post again reminds me the global warming effect.These discussions are normally full of nourishment.

  38. 38
    rv says:

    #36: The subtitle of Spencer´s book suggests, that there is some “intelligence” that drives the climate and fools the scientists – in the same way as evolution is driven by some intelligent designer that fools the scientist with fossiles indicating that random mutations, change of environment and selection are drivers of evolution.

    It seems that Spencer´s views on evolution and climate are consistent.

  39. 39
    Peter H says:

    How is it that so many here think they can encapsulate the concept of “intelligent design” within such narrow parameters. That’s like saying all Libertarians are ex republicans that don’t want to pay taxes. I have great faith in a higher purpose behind what reveals itself in the physical universe and I see no reason for any of it to conflict with my belief in evolution or any other well-vetted “scientific” theories. Muddling up the debate with philosophical interpretations is not science. Stick to the subject.

  40. 40
    CharlieT says:

    Phillip Machanick #35 -Is it really necessary to invoke any turtles at all?
    Whilst it is tempting to imagine that after 4.5 billion years the earth would have settled down, I am not sure it is true.
    Do the ocean currents and gyres now move at an unvarying pace, has the PDO always had the same rhythm – reconstructions seem to suggest that ENSO,at least, has varied over the course of the millenium. Is it unreasonable to think that cloud cover might vary from 68%, without any external forcing?

  41. 41
    Adam R. says:

    Not to put too fine a point on it, Intelligent Design is a sham and a fraud.

    School districts who have been duped into attempting to injecting ID into science curricula have discovered there is no actual theory, and thus nothing to teach. The scam was revealed in lurid detail in the Kitzmiller v. Dover Area School District trial, in which a Republican, Bush-appointed judge scoffed at the arguments of IDers and as much as called them liars. cf:

    That Spencer is a believer speaks volumes.

  42. 42
    Rod B says:

    Adam R, you mischaracterize Spencer. You need to read Peter H’s #39 and accept that creationists hijacked and adopted the term “intelligent design” and it no longer communicates alternative beliefs though still is confusingly used.

  43. 43
    Ray Ladbury says:

    Rod,Spencers belief in ID is germane only in that ID is not and can not ever be a scientific theory. It cannot make verifiable predictions. Failure to realize that calls into question one’s understanding of scientific method.

  44. 44
    Adam R. says:

    @42 Rod B. …accept that creationists hijacked and adopted the term “intelligent design”

    Sorry, but that’s baloney, Rod B. Creationists invented the term “intelligent design”.

    Dissembling by the likes of Behe notwithstanding, ID is and always has been creationism in disguise, as was clearly revealed in the Dover trial. Philip Johnson has flatly asserted that ID is an effort to give a scientific basis to creationism, and William Dembski, author of the spurious “specified complexity” argument, has said ID is “to enable God to receive credit for creation.”

  45. 45
    Rod B says:

    Adam, maybe so. The point is that the literal interpretation of “intelligent design” could be very far from creationism ala the bible. But creationists sunk their teeth in and said MINE!, and used it for their purposes as you say.

  46. 46
    Doc Savage Fan says:

    Ghan’s assertion is false that decadal variability in clouds can “only” be a response to decadal variability in the surface conditions or atmospheric circulation that drive cloud formation. He ignores the possibility that decadal variability may be caused by external forcing such as cosmic rays which are known to cause increased rates of aerosol nucleation. (

  47. 47
    Adam R. says:

    You continue to imply that ID was ever something other than creationism, Rod. This is simply not the case.

    Whoever originated or re-branded the idea of ID, it is still unscientific twaddle. One of its most prominent proponents, Michael Behe, admitted in court that his expanded definition of science that would allow ID also would have to include astrology.

  48. 48
    flxible says:

    “Intelligent Design” originated in the 13th century as the teleological explanation of “Gods creativity” to support biblical creationism. Stop hand waving RodB – some Christian scientists may believe Gods design was limited to first principles, to play out as they would – some folks [including some Christian scientists] may believe Gods design was a finished whole system that humanity has no influence on – Spencer is a Christian, no telling which way he swings, but he really appears to prefer the latter interpretation.

  49. 49
    Rod B says:

    Adam, we’ve probably beaten this horse enough, but many accounts credit Fred Hoyle with the first formal use of the term “ID” in 1982 — and distinctly not meaning creationism. Though there have been more than a few earlier maybe less formal (??) recorded uses as far back as 1847.

  50. 50
    Mark G. says:

    There is a transitional fossil between creation science and intelligent design, it’s called “cdesign proponentsists”. Look it up.