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MP Graham Stringer and CNN Crossfire are wrong about the 97% consensus on human-caused global warming

Posted on 14 February 2014 by dana1981

In May 2013, several Skeptical Science contributors published a paper showing that of peer-reviewed climate publications over the past 20 years that take a position on the cause of global warming, 97 percent agree that humans are responsible.  Since that paper was published, it's been met with extensive denialism

The reaction of denial is not surprising, because an expert consensus is a powerful thing.  People can't be expert in every subject, so we defer to the consensus of experts on many subjects.  For this reason, climate scientists are the most trusted sources of climate science information.  As we documented in our paper, research has also shown that when people are aware of the expert consensus on human-caused global warming, they're more likely to accept the science and support climate policy to address the problem. 

Hence, those who support the status quo and oppose efforts to reduce greenhouse gas emissions have long engaged in a disinformation campaign to misinform the public about the expert consensus.  Their efforts have been successful, as evidenced by the 'consensus gap' whereby the public believe scientists are split on the cause of global warming; a stark contrast to the reality of the 97 percent consensus.

consensus gap

One of the most common contrarian reactions to the results of our paper has been to claim that 'skeptics' are included in the 97 percent as well.  For example, in a recent hearing reviewing the UK 4th carbon budget, Labour Party Member of Parliament (MP) Graham Stringer said of the expert consensus on human-caused global warming,

"somebody like me, who is probably more sceptical than you are about this issue, would be included as a supporter of the consensus, whereas I am not? Many major scientists have complained that, in the review of their papers, they have been included in that consensus."

On CNN Crossfire, the conservative think tank Heritage Institute's David Kreutzer said,

"what they agree on is so innocuous that all of what you call deniers agree with it, as well. That the world is getting warmer, all right? And that some of that warming is due to man, maybe a significant amount."

Similarly, contrarian climate scientist Roy Spencer claimed in Congressional testimony last year that he's included in the 97 percent. 

"There's a recent paper by John Cook and co-authors who looked at thousands of research papers which have been published in the scientific literature to see what fraction support the scientific consensus on global warming. Well, it turns out that the 97% consensus that they found, I am indeed part of and Senator Sessions mentioned he would agree with it too. And my associate John Christy, he agrees with it. In fact, all skeptics that I know of that work in that business. All are part of that 97% because that 97% includes those who think humans have some influence on climate. Well, that's a fairly innocuous statement."

These statements are all incorrect, ignoring a significant part of our research. They are based on one of the categories used in our study regarding "implicit endorsements" of human-caused global warming.  A paper that was included in this category:

"Implies humans are causing global warming. E.g., research assumes greenhouse gas emissions cause warming without explicitly stating humans are the cause"

This particular category doesn't state how much global warming humans are causing, and hence climate contrarians claim that because they admit humans are causing some global warming, they should be included in the 97 percent. 

However, this argument only considers one of the seven categories used in our study.  Another critical category, the "implicit rejections" included any paper that (emphasis added):

"implies humans have had a minimal impact on global warming without saying so explicitly E.g., proposing a natural mechanism is the main cause of global warming"

Hence for example, one of Roy Spencer's five papers captured by our literature search was put in this category, because it proposes negative feedbacks will minimise future global warming.  His other four papers fell into the 'no position' category; therefore, overall Spencer was not included in the 97 percent as he claimed in his testimony to US Congress.  Rather, Spencer's research is included in the 2 percent of papers minimizing or rejecting the human influence on global warming (the final 1 percent of papers were uncertain about the cause).  Spencer has also said "I think it is more likely that the warming is mostly natural," so his opinion is consistent with the 2 percent.

For those desiring papers with more explicit positions on the cause of global warming, we also used categories that only included papers that explicitly quantified the human contribution to global warming.  We asked the scientific authors to rate their own papers, and of the papers in those categories (237 total), 96 percent agreed that humans are responsible for the majority of the current global warming.

Therefore, if anyone claims to be part of the 97 percent, it means they disagree with the contrarian argument that humans are having a minimal impact on global warming.  Moreover, in order to be part of the 96 percent expert consensus, they must explicitly agree that humans are responsible for the majority of the global warming over the past half-century (a position the latest IPCC report took with 95 percent confidence). 

Those like Spencer, and possibly Stringer and Kreutzer, who believe the human influence on the climate is minimal,  hold fringe views that are consistent with just 2 to 3 percent of the peer-reviewed climate science literature.

This post has been incorporated into the rebuttal to the myth Deniers are part of the 97%.

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Comments 1 to 38:

  1. Is it possible to look up somehwere, like on the Concensus Project page, how a specific paper or author is classified?

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  2. I see one can look up the classifications on the Skeptical Science page.

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  3. dana1981,

    I'm not sure whether or not you realize that it is an entirely reasonable position to agree with both of the "consensus" arguments (i.e. that the planet has warmed, and that human activities are responsible), and still not support "climate policy to address the problem".

    The "97% consensus" that's you're reporting has nothing to say regarding any of the following, each of which is an essential link in the chain of reasoning that corrective policy action must be taken.

    1. How much will GHG emissions rise in a "business as usual" scenario?
    2. How much will atmospheric concentrations rise for that level of emissions?
    3. How sensitive is the climate to increased GHG concentrations?
    4. How long will it take for changes to manifest?
    5. How will those changes impact ecosystems, economies, societies and individuals (considering both positive and negative impacts)?
    6. What is the net cost / benefit of the expected changes (allowing for the possiblity and costs of adaptation)?
    7. What policy actions are politically feasible and economically viable?
    8. At best, how much can those actions actually reduce emissions below "business as usual"?  
    9. With what probability of success?
    10. Over what time frame?
    11. At what cost, and with what unintended side-effects?
    12. And ultimately... will the probability-adjusted future benefits of policy action (discounted to present value), exceed the real direct and indirect costs of taking action, and will those costs and benefits be distributed equitably?

    According to your definitions, I'm part of the "97% Consensus", but I still do not support the vast majority of proposed "climate policies" because I have numerous doubts relating to the dozen issues I've listed above.

    FWIW, there are small number of "climate policies" that I would support even if climate change was not a problem, and they had no impact on emissions (e.g. ending energy subsidies).

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  4. Russ R O.K. lets take the first one, what do you think the uncertainty is on the subject of GHG emissions in a "business as usual" scenario?  Do you think they are going to be substantially less than RCP 8.5?  If so, please explain why.

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  5. RussR"According to your definitions, I'm part of the "97% Consensus"..."

    Unless you were an author of one of the papers analysed, you aren't.

    Your comment has little to do with the research refered to in the article.

    But supposing you were an author. Fine you are entitled to your opinion, which is still irrelevent though in the context of the research, which was about scientists agreeing about the science, not about whether any subsequent policy was good or bad.

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  6. Russ R:

    This article is meant to clear up misconceptions being spread by self-styled skeptics regarding the nature of the scientific consensus in general, and the Cook et al paper in specific (e.g. the deconstruction of Dr Spencer's claim).

    Dr Spencer may well agree that the Earth is warming and humans have contributed, but his statements - "I think it is more likely that the warming is mostly natural" - and the papers of his assessed in Cook et al, show that his work and views fall into the category "implies humans have had a minimal impact on global warming" - in other words, he is contradicting himself if he claims to be "part of the 97%".

    Whatever the merit to your views on specific policies viz. climate, they do not seem to have anything to do with whether Dr Spencer, the Hon. Mr Stringer, or Dr Kreutzer (and others) are propagating misconceptions regarding the scientific consensus or not.

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  7. Russ R. - I find your list interesting, but your assertion that these are unaddressed questions is not supportable.

    • 1-4 on the greenhouse effect are basic science, as per the overviews in the IPCC WG1 publications here and here. If you wholly disagree with any of those you are in the 3% of dismissives. 
    • 5 on impacts has certainly been studied, see the IPCC WG2 "Impacts, Adaptcation, and Vulnerability" for an overview. 
    • 8-10, how fast and how much AGW can be reduced, depend entirely on the mitigation policies that are actually implemented - politics. 
    • 6, 7, 11, and 12 on cost/benefit ratios have been the subject of many studies; there are reasonable references here and here. In general economic studies of mitigation versus adaptation find mitigation advantageous by a factor of 5-10x over adaptation. I would suggest discussion on economics take place on those more appropriate threads. 

     The basic science is what it is, and that is where the oft-referred to 97% consensus is found. Economic studies vary quite a bit, but the ones not showing strong mitigation benefits tend to have some very unreasonable assumptions. And the policies and responses are strictly political in nature, although one hopes they are informed by the science. 

    Your objections and issues appear to be (IMO) primarily economic/political - that's really rather off-topic in a thread regarding consensus on science. 

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  8. Dikran Marsupial & KR,

    Please show me where any of these 12 questions were addressed as part of the "97% Consensus" in the paper being cited.  They're not.  The paper (and the much touted 97% Consensus") only addressed two very narrow and simple questions.  (Is the earth warming? and Are humans responsible?)    I happen to agree with both positions, so no issues there.

    I have two issues with how this is being used (by folks from this site and others).  

    First, the "consensus" is being misrepresented as being broader than it actually is.  For example, here:  Obama twitter 97%

    Pardon?  Where exactly did "dangerous" come from?  It wasn't part of the study, which make the third part of the statement completely unsubstantiated.  Okay, the president probably didn't actually read the paper himself.  But did anybody bother to correct that very public mistake?  It appears not.

    Second, this "97% consensus" is being presented, in and of itself, as justification for policy action, taking for granted all of the rather important questions that I listed above.  Here for instance:

    "With the latest study showing 97 percent certainty about climate change being caused by human activity, we're 100 percent certain that Congress needs to pass serious climate legislation such as a revenue-neutral carbon tax."  - Dana Nuccitelli  (

    If that's not an a serious leap of reasoning, I don't know what is.  (And I'm not even opposed to a revenue-neutral carbon tax, so my taking issue with Dana's statement isn't ideological.) 

    Basically, if you're going to claim that "97% of climate scientists agree", you have to be specific on what it is that's actually being agreed on.  You have to not misrepresent the "consensus" as applying to matters that weren't covered.  And lastly, you have to acknowledge that people who agree with the two "consensus" positions can still oppose "climate policies" (for a bunch of reasons), without labeling them "deniers".


    Paul D.,

    "Unless you were an author of one of the papers analysed, you aren't."  You're entirely correct.  I should have written that I'm in agreement with the "97% consensus".



    I agree with you re: Spencer.  He can't have it both ways.

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  9. KR.

    Here's where you're guilty of misrepresenting the "97% consensus":

    "[Questions]1-4 on the greenhouse effect are basic science, as per the overviews in the IPCC WG1 publications here and here. If you wholly disagree with any of those you are in the 3% of dismissives."

    Since questions 1-4 weren't covered in the paper, how can they be part of the "97% consensus"?

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  10. Russ @8...  Jeez, I wish you guys would apply even just a tiny fraction of scrutiny to the claims a wide range of high profile individuals who challenge man-made climate change. 

    Why not apply the same level of scrutiny to WUWT. Or to ClimateAudit. Or Pielke, Curry, Tol, Monckton, Ball, Carter, Humlum, JoNova, or any of a very very long list of people who torture the facts.

    The OFA drops in one word that oversteps and all hell breaks loose. All the while, others on the "skeptic" side get away with intellectual murder.

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  11. KR @7, Russ's list is indeed consistent with the consensus as assessed by the Consensus Paper (Cook et al).  That only assessed endorsement in papers of the proposition that >50% of recent warming was due to anthropogenic factors.  There is indeed general agreement on far more issues than addressed by the paper, as explored by the IPCC; and the "consensus position" does indeed contradict most of Russ's list, but that is a seperate issue.

    Note, it is possible to accept even a low climate sensitivity (about 1.5 C per doubling of CO2) and that most recent warming has been anthropogenic if you also believe that aerosol forcings have been low, and the natural contribution of natural cycles to recent warming is close to, but below 50%.

    Having said that, Russ's conclusions from his list of questions would appear to rely on some very dubious inferences, or on simply ignoring relevant data.  The "no problem" view of climate change relies on assuming the truth lies in the lower 16% range of IPCC uncertainties across a range of issues.  Those uncertainties compound so that the probability that no action is a reasonable strategy is very small.  

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  12. Russ,

    The consensus science position on all of your points is outlined in the IPCC report.  You are claiming that an enormous search of the literature must be done for each claim that you have made.  That has been done by the IPCC.  The consensus project documents in explicit detail that the consensus is extreme.  That consensus also relates to the entire IPCC report, which is approved by every contry in the world.  It is up to you to produce evidence that the consensus as shown in the IPCC report is not accepted.  That is impossible, since the IPCC is a consensus document.  

    You are hair splitting.  It is unnessaary to prove every claim in the IPCC document, since it is acccepted as consensus.

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  13. Rob @10, while it is quite appropriate - even necessary - to point out the OFA's mistake.  The mistake was confusing the consensus position as assessed by the paper with the consensus of scientists as assessed by the IPCC.  That the consensus of climate scientists finds that global warming will be dangerous is in fact shown by the IPCC.  It is, however, not assessed by the paper.

    However, the obsessiveness with which this is brought up is revealing.  It is almost always brought up on any discussion of the paper, as though it was a mistake by Cook et al.  Further, it is brought up by people who give free passes to outrageous falsehood from the other side, as you note.

    Of course, it is possible that Russ is different.  If so, he can undoubtedly link us to his criticisms of errors in the science by Senator Inhofe (for example).  Failing that, we can assume his mention of the OFA tweet represents merely an attempt to belittle the paper with a convenient talking point rather than a serious contribution.

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  14. Tom...  Totally. I have no problem at all when people point out errors. The OFA definitely overstepped when they added the word "dangerous." 

    What drives me up a wall is a disproportionate expectations of accuracy. If someone is going to be a stickler for accuracy, the OFA's error, on the grand scale of climate change related errors, hardly registers on the meter.

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  15. Russ R

    'Second, this "97% consensus" is being presented, in and of itself, as justification for policy action'

    Actually no Russ. What it is being presented is that supposed lack of consensus on the science, that there are substantial debates about much of the basics among the scientific community, is not true. Consensus on the science is not a sufficient basis for policy action. But it is an important part of the basis needed. In contrast a substantial lack of consensus, were that the situation, might well constitute sufficient grounds for not taking policy action.

    Thus demonstrating that the consensus does exist removes a justification for policy inaction and contributes, although is not sufficient alone, to a justification for policy action.

    Thus it is obvious why the idea that there is no consensus is so powerfully seductive to those who don't want policy action, whether needed or not. And it is telling when some folks will promulgate the 'there is no consensus' line in contradiction of the actual evidence. I can't imagine a starker example of the 'black is white' form of motivated reasoning.

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  16. Also Russ, your point 7

    'What policy actions are politically feasible and economically viable?'

    I would reword

    'What policy actions are politically feasible, economically viable or morally required?'

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  17. Russ's list @3 can be described as an example of impossible expectations on the science by those who are "inconvenienced" by the evidence. Cook et al 2013 addresses a simple question, the answer to which may have some policy implications. But because Russ seemingly does not like those potential implications, he questions the usefulness of Cook et al 2013, arguing that it would only be useful if it addressed all questions from his list. I presume, in his view, the "scientific consensus" in climate science cannot be valid/useful unless sicentists agree on all his 12 points.

    First of all, a poll consisting of such detailed points on 10K+ papers would not be possible due to too many details involved. Second, there will be not many (in any) climate sicentists who agree on all 12 points, because most of the points are about economics/politics as other commneters noted, and most notably, climate scientists are not experts on those point, therefore such study would not be a study of expert consensus but rather of casual population opinion.

    In conclusion, Russ's list bears signs of a science denial trait: impossible expectations.

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  18. The OFA post is accutate and does not require any corrections.  Obama has referred to the 97% consensus of the Consensus Project and the separate, well known scientific consensus that AGW is dangerous.  He is sending a tweet and has limited characters.  Arguing that he must explain in detail what he means in a tweet is absurd.

    Tha argument that Obama's post is incorrect must provide evidence that scientists do not consider AGW dangerous. Russ has provided no references to his wild claim that there is not a scientific consensus AGW is dangerous.  Russ's claim that he does not agree with the consensus on some points is immaterial.  A glance at the IPCC WG2 report is sufficient to show AGW is dangerous.   Since there is a scientific consensus that GW is dangerous the tweet is accurate.

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  19. RussR@8 I see you have completely ducked the question I asked in order to find out the evidence underpinning your doubts on your first of 12 concerns.  Ducking the question is a tacit admission that you have no evidence to support such a doubt and are just invoking the "uncertainty monster" as a reason to advocate a lack of action on climate change.

    Sorry, my mind is changed by evidence and reason, it is not swayed by empty rhetoric and bluster.

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  20. Michael Sweet @18, you need to read the most recent survey of climate scientists by Bray and von Storch (along with the earlier versions).  These surveys are not without their methodological problems, but provide a reasonably accurate assessment of the detailed opinions of climate scientists.  

    Of particular interest to what follows is an issue with the phrasing of the question.  They ask, "How convinced are you that ..." on a number of issues.  They then allow responses from 1 to 7, with '1' being interpreted as "not at all convinced", and '7' being interpreted as 'very much convinced'.  The problem arises that we can plausible say we are "a little bit convinced" (ie, approximately equivalent to '2') when we are either seriously in doubt, but open to the possibility that we are mistaken; or when we think it is a slightly better than a 50/50 prospect.  This ambiguity, IMO, has the potential to bias the results low by an indeterminant amount.

    With that caution, I note three interesting results.  

    In response to question 26, "How convinced are you that climate change, whether natural or anthropogenic, is occurring now?", 95% are significantly convinced (response of 5 plus).

    In response to question 27, "How convinced are you that most of recent or near future climate change is, or will be, a result of anthropogenic causes?", 81% are significantly convinced.  That question is the closest to the view assessed in Cook et al.  The 81% result is significantly lower than the 97% obtained by Cook et al, and by other related surveys.  That may be because of methodological flaws in Bray and von Storch, possibly relating to sample size, or bias.  The bias may have been introduced by self selection bias.  That is, Bray and von Storch are associated with a low estimate of climate senstivity, and that association may have lead scientists of the opposite view to not cooperate with their survey.  It may be that climate scientists are in general less convinced than their evidence (as measured by endorsement in scientific papers) suggests.  Or it may be that the bias is on the other foot, ie, to be found in Doran, Cook et al's and other equivalent results.

    Finally, in response to question 28, "How convinced are you that climate change poses a very serious and dangerous threat to humanity?", 72% are significantly convinced. 

    For this discussion, the important point is that the level of agreement among climate scientists is not the same for the three propositions.  Indeed, only 89% of climate scientists who agree that that recent (or near future) global warming is (or will be) the result of anthropogenic causes also agree that global warming is "...a very serious and dangerous threat to humanity".  It follows that the OFA did make an error.  Frankly, I consider that to have been transparent from the language, but even assuming them to have been making the more complex statement you assume, they are still in error.

    Having said that, it still remains that a clear super majority of climate scientists think that:

    1)  Global warming will be "...a very serious and dangerous threat to humanity" (my emphasis);

    2)  We are "... beginning to experience the more gradual impacts of climate change" (question 29, 82% significantly convinced);

    3)  The general public should be told to be significantly worried about climate change (question 39, 80%);

    4)  There "... is a great need for immediate policy decisions for immediate action to ADAPT to climate change" (original emphasis, question 40, 70%);

    5)  There "... is a great need for immediate policy decisions for immediate action to MITIGATE climate change", (original emphasis,  question 41, 77%); and that

    6)  Global warming has become a more urgent issue of the last 5 years (question 42, 70%).

    Finally, 56% of climate scientists think the evidence indicates the impacts of climate change will be worse than they thought it would be 5 years ago (question 43).  That compares to just 7% who think the evidence indicates the impacts will be less severe.

    I think this clearly, and comprehensively underlines the fact that while the OFA made a mistake, the potential to misinform from that mistake was very small.  Climate scientists overwhelmingly believe that global warming will be very dangerous; and that the case that global warming is anthropogenic keeps improving.  They overwhelmingly believe that urgent action to mitigate global warming is required now.  And the overwhelmingly believe that an additional five years evidence has either shown no decline in the threat, or has increased the threat from global warming. 

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  21. Tom,

    We will have to agree to disagree on this one.  When you write me 8+ paragraphs to explain why a twitter post is in error, I think the twitter post is fine.  I agree completely with your final paragraph.  Your entire post is a thoughtful consideration of the issue.  It is too long for twitter.  

    We differ on the OFA twitter summary.  In my view, the OFA twitter correctly reflects scientific opinion.  I do not think the OFA should be held to the same standard as a peer reviewed publication in Nature. When deniers constantly make up stuff, we cannot expect politicians that support action to be perfect.

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  22. One at a time Ladies and Gentlemen.

    Rob Honeycutt,

    I do apply the same scrutiny to voices on both sides of the debate.  

    I ignore the extremists altogether because their positions are nowhere close to reality, and arguing would be a complete waste of my time and effort.  

    Most of the others I take with a figurative grain of salt.  I make myself aware of their biases and give credence only to the areas where they have some knowledge, ignoring their opinions on other matters.  

    When and where I bother to comment is to point out mistakes in fact or reasoning, and only with individuals who I think might actually respond constructively. 

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  23. Tom Curtis,

    Good to see you again, and thank you for continuing to be as fact-based and scrupulously analytical as I remember.

    First, I wrote my comment here to Dana because I believe that he is being sloppy. He quite rightly points out that individuals who accept only "minimal" impact from human activities are not part of the "97% Consensus" (he should know, he was a co-author").

    However, he goes on to attack "those who support the status quo and oppose efforts to reduce greenhouse gas emissions" saying they "have long engaged in a disinformation campaign to misinform the public about the expert consensus." I'm making the point that one can be completely reasonable in opposing "climate policies", while still completely agreeing with the "97% consensus", because the two "consensus" positions are not sufficient on their own to necessitate action.

    Second, you wrote: "Of course, it is possible that Russ is different. If so, he can undoubtedly link us to his criticisms of errors in the science by Senator Inhofe (for example)." While you know this line of argument is clearly ad hominem, I'd be happy to indulge your request. Since I'm not an American, I don't pay much attention to Senator Inhofe, so I haven't felt the need to find and correct his errors.  But if you want an example of me being impartial and objective, back last summer while I was giving you and others here a lesson on the economics of gasoline taxes in British Columbia, demand elasticity and exchange rate differentials, I was also arguing with a regular over at WUWT over his opposition to the BC gas tax based on a flawed economic argument.  (As a financial analyst by profession, economics is one of the few things I know a bit about, and I like to limit my arguments to things that I know something about.)

    In this case... I know what Cook et al (2013) said, I know what it didn't say, and I know that the way it's being applied and presented is not entirely in keeping with what it actually said.

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  24. Russ R@23:

    1)  You are correct that you can both oppose mitigation of AGW and accept the concensus that greater than 50% of recent global warming has been caused by anthropogenic factors.  However, that in no way obviates Dana's claim about the actual strategies of AGW deniers.  They need not have taken that strategy, but as a matter of historical record, they did.  Consequently, I am not sure what point you are trying to make.  Perhaps it was that when given a choice of an honest strategy, they chose a dishonest one?  

    2)  Russ, I am glad to see that you have in fact criticized those on your own side on at least one occassion when they deserved it.  Given that the person criticized was Willis Eschenbach, I would point out that he has deserved such criticism far more than just once.  Be that as it may, willingness to speak up about errors on your own side deserves real respect IMO, so well done.  FWIW, I asked about criticisms of Inhofe (a US Senator) because you had chosen to criticize the office of the US President.    

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  25. It is not surprising that the peer-reviewed work of Roy Spencer is a lot less contrarian than his stated opinion on interviews, or his blog posts. Once you have to back up your speech with evidence, you will start to align yourself a lot more with the mainstream consensus - and for a good reason.

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  26. Tom Curtis,

    "You are correct that you can both oppose mitigation of AGW and accept the concensus that greater than 50% of recent global warming has been caused by anthropogenic factors."

    For the record, I don't categorically oppose all mitigation policies.  Some are sensible, some may or may not be effective, and some are very likely to do more harm than good.

    "However, that in no way obviates Dana's claim about the actual strategies of AGW deniers. They need not have taken that strategy, but as a matter of historical record, they did. Consequently, I am not sure what point you are trying to make. Perhaps it was that when given a choice of an honest strategy, they chose a dishonest one? "

    I agree, people make disingenous arguments all the time... some do so habitually.  I see this on both sides.  I'm not defending them.  The point(s) I am trying to make, and I apologize for not having been sufficiently clear, are as follows:

    1. Not everyone who opposes a given climate policy is "a denier".  One can fully accept the "97% Consensus" (or a more general form of scientific agreement), yet not be convinced that various policy actions are warranted or will be effective.  There are plenty of good-faith reasons that people may differ in their beliefs. 
    2. The much touted "97% Consensus" is much narrower than it is frequently portrayed. It is often misrepresented (for example by Barack Obama and KR above) as supporting positions that weren't tested in the paper.  Also, it is not, by itself, sufficent justification for any policy action, let alone grounds for being "100 percent certain that Congress needs to pass serious climate legislation..." as Dana wrote in the Sacramento Bee.

    That's all.

    "Russ, I am glad to see that you have in fact criticized those on your own side"...

    I try not to take sides in this.  I don't believe there is a right side or a wrong side here.  There are good and bad arguments on both sides.  I try to correct the bad arguments, but only where I think the person making the argument would actually be receptive and my efforts aren't going to be wated. I have better things to do my time.

    "Given that the person criticized was Willis Eschenbach, I would point out that he has deserved such criticism far more than just once."

    To Willis' credit, he is meticulous with his analysis, he shows all his work, he debates in good faith, and he admits when he's wrong.  Also, he is very quick to point out errors from "his own side".  One very recent example...

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  27. Russ...  That WUWT you link to is an excellent example of the relative difference in errors presented on each side.

    At SkS, each of the posts goes through an internal review process. We apply skepticism, ask questions, point out errors or other problems well before anything sees the light of day on the site.

    At WUWT you have a near constant litany of fundamentally wrong information being presented without even the first hint of skeptism. AND the only litmus test ever applied for any article is that it side toward the rejection of AGW. Period.

    That article suffered from an error a highschooler should have been able to pick up on. He's presenting transient sensitivity and claiming it's equilibrium sensitivity.

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  28. Rob Honeycutt,

    Yes, I spotted that error immediately, in fact, just from reading the headline I figured he'd made such a mistake (ignoring thermal inertia and time lag), and reading his first few paragraphs confirmed it.

    I would have been very pleased to take the author to task on it, but I was denied the opportunity as several commentators had already beaten me to it.

    "At SkS, each of the posts goes through an internal review process. We apply skepticism, ask questions, point out errors or other problems well before anything sees the light of day on the site."

    My humble observation is that the  collective "skepticism" here is only ever applied in one direction.  And the term for that is "confirmation bias".  As an example:  

    BTW, I'm not singling out SkS for being "selectively skeptical"... everyone does it.  It's immensely difficult to be critical of arguments when you already agree with the conclusion.

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    Moderator Response:

    [JH] Rob Honeycutt's statement applies to original articles posted on SkS. Reprints of articles, the weekly digest, and news roundups are not subject to a rigorous internal review process prior to posting.

  29. Russ R - Regarding the list you presented above, I will accept the correction that not every part of the science has a 97% consensus, and that the Cook et al paper did not go into details on every aspect of the science - simply on whether we are responsible for recent warming. My apologies if I conflated that particular paper with the (generally understood) science as present in the literature. 

    That said, the basics of the greenhouse effect have been understood for roughly 150 years, the IPCC report is a reasonable summary of the state of the science, and significant disagreement with 1-4, and even 5, of your list puts anyone holding said disagreement in a distinctly minority position. The rest of your post is economics (reasonable debate possible on underlying assumptions such as discount rates and carbon costs, although still quite significant agreement) and political policies, which are not the subject of the Cook et al paper (or this thread)

    After some thought, I went back to previous discussions - you have in fact made quite the same arguments with me over a year ago, on WUWT, and I continue to disagree with you on the same grounds as then.

    The 'consensus gap' evident in the political landscape, the difference between expert opinion on AGW and the public perception thereof, is an ongoing impediment to reasoned action. Public policy should be informed by the best information available, and the many denials of consensus in the public sphere are an impediment to a well informed public response. If you disagree with the consensus measured by Cook et al, support your argument on the appropriate threads. If you object to a public understanding of that scientific consensus, I would ask why you feel that policy decisions should be made under perceptual errors on expert opinion. 

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  30. .

    Since this thread is - more or less - about public perception of concensus - I offer this link to today's London Sunday Telegraph.

    Christopher Booker is a sainted (by his followers) jounalist who specialises in dissing AGW on a regular basis.

    It is quite evident to those who read his blog regularly that each week there are fewer and fewer people bothering to post the scientific case for AGW: they are just shouted down, often in offensive language, with the same old, unsupported and refuted, arguments.

    I see no way to "persuade" most of these people of the reality of the problem.



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  31. Forgot to add the link!

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  32. @Wol.  There was a takedown of Booker and the article in question earlier today by Tim Fenton:

    Booker Exposed As Total Charlatan





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  33. Russ R. - In my reading of all the comments on the WUWT post you cited, the author did address the ECS vs. TCR issue.  Are you saying it wasn't adequately resolved?

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  34. KR @29,

    I had completely forgotten that we had previously debated this very issue at WUWT.  Thank you for linking to it and refreshing my memory.  Nice to see that some people can still be civil even when they disagree. 

    Anyway, having seen the less-than-polite response you got over there, I don't blame you for giving up in frustration.  It's not easy trying to respond to a barrage of simultaneous attacks, as I'm finding out here.

    If you disagree with the consensus measured by Cook et al, support your argument on the appropriate threads.

    I don't disagree with it.  At all.  What I disagree with is misrepresenting that "97% Consensus", extending it to cover areas that it never addressed.

    If you object to a public understanding of that scientific consensus, I would ask why you feel that policy decisions should be made under perceptual errors on expert opinion.

    Far from objecting to a public understanding of the consensus, I feel that public dialogue should accurately reflect exactly what the study acutally found.

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  35. Hence for example, one of Roy Spencer's five papers captured by our literature search was put in [category 5], because it proposes negative feedbacks will minimise future global warming.

    This concept of "capturing" a specific paper in a category and naming its authors does not seem to be an intrinsic part of the Cook et al paper's methodology or purpose, so I wondered if the authors of the Cook et al paper could answer a question for me?

    If the Cook et al authors think a paper can be captured in a category like this by the initial abstract rating process, would a later different author(s) self-rating "release" the paper from this category?

    For example, with this category 5 captured paper of Spencer's (which had 3 other authors), had Spencer and one other author replied with a rating of 3, and the two other authors with the abstract rating of 5, this would mean the overall rating would be 4 wouldn't it?

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    Moderator Response:

    [DB] Fixed text per request.

  36. @DB

    Redundant comment so remove if you want but I'm happy with the fix of my comment and thanks for fixing it.

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  37. tlitb1 @35, it is fairly obvious even to this non-author that:

    1) The papers were "captured" by the search, not "captured" into a category.  That is, the literature search can be viewed metaphorically as a net which 'caught' 12,280 papers, which were then sorted into their appropriate categories.  Your misinterpretation is both typical of you, and from past experience, probably deliberate.  Whether deliberate or not, it has no justification in the text of the article.

    2)  Even casual readers of the paper will have noted that the abstract raters rated the papers only on the abstract and title, all other information (including date and journal of publication, and authors names) being withheld.  In constrast author self ratings were based not only on the full paper, but also on whatever memories they had of their intentions for the paper.  As such, the two sorts of ratings do not, and cannot compounded into a conglomerate rating as you suggest.  If the authors disagree with the abstract ratings, that may be simply because they are rating a different thing.  It is presume that abstracts are related to the contents of papers, so that on average the pattern of ratings by authors represents a check on the accuracy of both the method of rating papers by abstract alone and on the accuracy of abstract raters.  Differences in the rating of individual papers, whoever, can be the consequence of to many different factors to safely attribute them to any one factor (at least without a lot of additional information).

    3)  In constrast, a large difference between the author rating of the same paper by various authors can only be attributed to either misunderstanding the rating categories, or (hopefully less likely) misunderstanding their own paper by one or more of the authors.  A difference of just one point in self rating, however, may simply be attributable to slighly different subjective judgements, which cannot be completely excluded.  In the scenario you describe, at least two of the authors have misunderstood the rating categories.

    4)  In this case, Spencer makes an explicit claim about how he would be rated, a claim which is shown to be false by the actual facts.  That is fairly clear evidence that he is misdescribing how the ratings should apply.

    In fact it is very interesting to compare Spencer's reaction to that of Dr Nicola Scaffeta, who when asked a question about the rating of one of his papers had this to say:

    Question: "Dr. Scafetta, your paper ‘Phenomenological solar contribution to the 1900–2000 global surface warming‘ is categorized by Cook et al. (2013) as; “Explicitly endorses and quantifies AGW as 50+%“

    Is this an accurate representation of your paper?"

    Scafetta: “Cook et al. (2013) is based on a strawman argument because it does not correctly define the IPCC AGW theory, which is NOT that human emissions have contributed 50%+ of the global warming since 1900 but that almost 90-100% of the observed global warming was induced by human emission.

    What my papers say is that the IPCC view is erroneous because about 40-70% of the global warming observed from 1900 to 2000 was induced by the sun. This implies that the true climate sensitivity to CO2 doubling is likely around 1.5 C or less, and that the 21st century projections must be reduced by at least a factor of 2 or more. Of that the sun contributed (more or less) as much as the anthropogenic forcings.

    The “less” claim is based on alternative solar models (e.g. ACRIM instead of PMOD) and also on the observation that part of the observed global warming might be due to urban heat island effect, and not to CO2.

    By using the 50% borderline a lot of so-called “skeptical works” including some of mine are included in their 97%.”

     First, Scaffeta grotesquely misrepresents the IPCC position, which is that greater than 50% of warming since 1950 has been anthropogenic.

    Second, the abstract of his paper reads as follows:

    "We study the role of solar forcing on global surface temperature during four periods of the industrial era (1900–2000, 1900–1950, 1950–2000 and 1980–2000) by using a sun-climate coupling model based on four scale-dependent empirical climate sensitive parameters to solar variations. We use two alternative total solar irradiance satellite composites, ACRIM and PMOD, and a total solar irradiance proxy reconstruction. We estimate that the sun contributed as much as 45–50% of the 1900–2000 global warming, and 25–35% of the 1980–2000 global warming. These results, while confirming that anthropogenic-added climate forcing might have progressively played a dominant role in climate change during the last century, also suggest that the solar impact on climate change during the same period is significantly stronger than what some theoretical models have predicted."

    (My emphasis)

    The phrasing, "as much as" indicates that the upper limit is being specified.  With solar activity specified as only contributing "as much as" 25-30% of warming since 1980, the rating of the abstract was eminently justified.

    What is interesting, however, is the stark contrast between Scaffeta's misinterpretation of the rating, and that by Spencer.  Interestingly, all early commentary on the paper by AGW "skeptics" followed Scaffeta's line (if not quite so extremely).  Then a new, and contradictory talking point developed, ie, that used by Spencer.  Some at least Anthony Watts have happily presented both views.

    I suspect it is fortunate for a number of AGW "skeptics" who self rated that their self ratings are confidential (unless they choose to release them), for I suspect quite a few of them will have rated them as rejecting the concensus, and are now publicly declaring that they ratings must be interpreted such that they are part of the 97%.  As I have not seen the data, that is, of course, just a guess.

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  38. @ 37. Tom Curtis

    As such, the two sorts of ratings do not, and cannot compounded into a conglomerate rating as you suggest.

    I'd like to assure you that I do not think that the abstract ratings should be merged in any way with the self-ratings. On the contrary, it seems more logical to assume that scientist self-ratings of their papers override, or displaces, the former rating.

    I think you agree with on this point since you say:

    ...on average the pattern of ratings by authors represents a check on the accuracy of both the method of rating papers by abstract alone and on the accuracy of abstract raters.

    I.e. by using the author ratings as a 'check' like this, it implies they are trusted to be a reliable bench mark. I don't see anything in Cook et al's methodology for considering errors, or throwing out false answers from the surveyed authors. So by implication they are taken to be the correct categorisation.

    So when you say:

    In this case, Spencer makes an explicit claim about how he would be rated, a claim which is shown to be false by the actual facts.

    I am not sure what actual facts have 'shown' any of his statements as false. Currently the only 'fact' I see is the category 5 rating of his papers' abstract as assessed by the Cook et al authors and bloggers here.

    I don't think Spencers contradicted that this has happened has he?

    I don't think Spencers statements have been explored thouroughly, but for the sake of argument, if Spencer is now publicly rating his own paper as category 3 I don't see how it can be said to be a false rating, or have any less validity than if he did this within the self-rating process.

    Surely the argument here isn't just that Cook et al rated one of Spencers works as category 5 and that is enough to define his stance?

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