Comments 1 to 43:

1. Robert Murphy at 11:58 AM on 16 June, 2010
   It's amazing how quickly the meme has spread in just a few days. In the same way that every "skeptic" knows that Jones said warming stopped in 1995, or that the decline in the "hide the decline" referred to a decline in late 20th century temperatures, this new one will be accepted as Gospel and will be trotted out every time someone mentions consensus in any way. The fact that Hulme has already come out and said he was misrepresented will be ignored.
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2. Chris McGrath at 12:01 PM on 16 June, 2010
   The direct link to Hume's paper is http://www.probeinternational.org/Hulme-Mahony-PiPG%5B1%5D.pdf
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3. Daved Green at 12:16 PM on 16 June, 2010
   This whole denial thing is fuelled buy general societies lack of education and interest in science and scientific principles , very intelligent people are taken in by these arguements , the solutions to AGW are seen to be "green" therefore leftwing even communist meaning the issue polarises into left and right politics . After watching Monckton are reading the comments on youtube and denier blogs I despair at as ever getting our act together . Keeep up the good work John and thanks to all the others who post , I read this every day .
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4. John Bruno at 12:50 PM on 16 June, 2010
   Robert, where did Hulme say he was misrepresented? I think that is interesting. A friend suggested before I post this, I should check in with Hulme. (I didn't) But the quote is from an article that he wrote, not something some reporter reported out of context. I read the paper and I think his point has been fairly represented by Bolt and others. Maybe Hulme can join in and explain himself.
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5. John Bruno at 13:04 PM on 16 June, 2010
   OK, there are some sites that seem to be somewhat misrepresenting Hulme a bit, mainly by paraphrasing and leaving out the "in the specific field of detection and attribution studies" of the quote, e.g., here
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6. Paulie200 at 13:19 PM on 16 June, 2010
   Wouldn't it be a little bizarre for scientists in the other two working groups to be talking about "Impacts Adaptation and Vulnerability" (WGII) or "Mitigation" (WGIII) of something they felt doesn't exist in the first place?
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   Moderator Response: good point. We call this steppingstone attribution.
7. Marcus at 13:19 PM on 16 June, 2010
   Actually, John B, I think Hulme himself is being extremely pedantic in a bid to shore up the incredibly weak Denialist Argument-& that the denialists are shoring things up still further by misrepresenting his pedantic position!
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8. John Bruno at 13:22 PM on 16 June, 2010
   Hulme's response is here. I am curious what others think, but I find this defense pretty flaccid. The spirt of the paper was quite critical of the IPCC, this was not merely a neutral review. Second, while Hulme may not have said "the ‘IPCC misleads’ anyone" he did write that "Claims such as ‘2,500 of the world’s leading scientists have reached a consensus that human activities are having a significant influence on the climate’ are disingenuous." So the IPCC has not misled but is disingenuous? Third, the point "That particular consensus judgement, as are many others in the IPCC reports, is reached by only a few dozen experts in the specific field of detection and attribution studies" is false. THAT is the main issue at hand. Hulme writes "The IPCC consensus does not mean – clearly cannot possibly mean – that every scientist involved in the IPCC process agrees with every single statement in the IPCC!" Well obviously, but nobody suggested that was the case (hello strawman). But to suggest that only a few dozen out of the many thousands of scientists that worked on AR4 agreed with the key take home message, that human activities are having a significant influence on the climate, or were qualified to do so is silly. (also note Hulme's argument has shifted (we have seen this tactic before too); initially it was that only a few dozen people were qualified to make that inference, but now he is saying not every author agreed).
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9. Marcus at 13:23 PM on 16 June, 2010
   Another thing, I find it hilarious how aggro Mr Bolt gets over the supposed deception of Rudd, given how often this guy ran to the defense of serial liar John Howard. For me, the politics of the people who support the theory of AGW is irrelevant compared to the *science*. After all, the first person I ever remember talking about the dangers of global warming was the noted Tory PM Margaret Thatcher. Given her background in chemistry, I figured she knew whereof she spoke!
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10. chris1204 at 13:50 PM on 16 June, 2010
    Mike Hulme seems to be concerned about the disconnect between 'the consensus' and the 'the sceptics' and the corrosive impact this has on the credibility of climate science in the wider community. In his response (link courtesy of John B @ 8), he writes: 'The point of this bit of our article was to draw attention to the need for a more nuanced understanding of what an IPCC ‘consensus’ is – as I say: “Without a careful explanation about what it means, this drive for consensus can leave the IPCC vulnerable to outside criticism.” The IPCC consensus does not mean – clearly cannot possibly mean – that every scientist involved in the IPCC process agrees with every single statement in the IPCC! Some scientists involved in the IPCC did not agree with the IPCC’s projections of future sea-level. Giving the impression that the IPCC consensus means everyone agrees with everyone else – as I think some well-meaning but uninformed commentaries do (or have a tendency to do) – is unhelpful; it doesn’t reflect the uncertain, exploratory and sometimes contested nature of scientific knowledge.' Unfortunately, those who point to the uncertainties in any particular line of evidence are then called cherry pickers. Mike Hulme seems to appreciate the complexities. Otherwise, you end up with something akin to the Cold War meme of arguments needing to be 'clearer than truth.'
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11. Joe Blog at 13:52 PM on 16 June, 2010
    John B at 13:22 PM on 16 June, 2010 Interesting link John B... But id put it to you that what he is claiming is that when people claim "2500(pick a number) IPCC scientists have reached a consensus." Its disingenuous... Because its actually relatively easy to prove this to be false. There may be 2500 contributors... But that doesn't translate to 2500 scientists in total agreement. And it becomes an easy task to prove other wise... thus its disingenuous. Take these comments from Dr. Andrew A. Lacis - NASA GISS On chapter 9 AR4 for example. "There is no scientific merit to be found in the Executive Summary. The presentation sounds like something put together by Greenpeace activists and their legal department. The points being made are made arbitrarily with legal sounding caveats without having established any foundation or basis in fact. The Executive Summary seems to be a political statement that is only designed to annoy greenhouse skeptics. Wasn’t the IPCC Assessment Report intended to be a scientific document that would merit solid backing from the climate science community – instead of forcing many climate scientists into having to agree with greenhouse skeptic criticisms that this is indeed a report with a clear and obvious political agenda. Attribution can not happen until understanding has been clearly demonstrated. Once the facts of climate change have been established and understood, attribution will become self-evident to all. The Executive Summary as it stands is beyond redemption and should simply be deleted." I dont doubt that he believes in AGW... But his comments could be used as proof of dissent... And it would take you 10 seconds on google to find many more examples. And to get lists of contributors.
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    Moderator Response: "... IPCC scientists have reached a consensus." Its disingenuous... Because its actually relatively easy to prove this to be false. There may be 2500 contributors... But that doesn't translate to 2500 scientists in total agreement." JB: Reaching a consensus does not = total agreement
12. Albatross at 14:13 PM on 16 June, 2010
    DeepClimate has some useful insight into how Dr. Hulme's comments have been misrepresented and distorted. Dr. Hulme is not pleased and has issued a clarification. This is yet another example of how "skeptics" intentionally mislead. As for consensus, let us not forget the poll reported in EOS: For details, for details on the poll please go here
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13. Philippe Chantreau at 14:22 PM on 16 June, 2010
    The Executive Summary might be a problem but something must be put together for policy makers, who usually lack scientific understanding in ways that seem "beyond redemption." Joe Barton has demonstrated, in congressional hearings, his cluelessness about continental drift. In the US, the vast majority of lawmakers and politicians are lawyers. Fred Thompson's inane comments on Mars are another case in point. Many other countries are plagued by the same problem. Putting things together so they understand is as difficult as doing it for the general public.
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14. Bern at 15:03 PM on 16 June, 2010
    To be honest, I rarely read the opinion pieces in The Australian, or any other Murdoch-owned paper, these days. I kind of know what they're going to say as soon as I read the title or the opening paragraph to find out what the subject is. It is curious, though, that Rupert Murdoch seems to have 'coincidentally' employed so many editors and commentators who just happen to be 'skeptical' about AGW. I guess, though, that they're just pandering to their specific audiences for those outlets. Mr Murdoch himself allegedly has a pro-AGW opinion - "Climate Change poses clear, catastrophic threats". That same article states that Fox & other parts of News Corp are going green(er), using renewables & offsetting emissions. It seems disingenuous (there's that word again!), though, to claim to be 'doing your bit' by offsetting your personal emissions while repeating some of the most blatant 'denialist' distortions to hundreds of millions of others.
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15. Doug Bostrom at 15:10 PM on 16 June, 2010
    Failing any evidence of the existence of draconian censorship, rank editorial misconduct or other significant corruption, obsessing about raw pro versus con personality counts in the pool of IPCC scientific resource talent is definitely a grade above the "Oregon Petition" but hardly seems worth much ink. The objective of the IPCC reports is a reasonable synthesis of the best published thinking on climate and anthropogenic influences on climate, not to produce an opinion poll based on what participants in the IPCC process itself think or believe. A critical review comment can and ideally should be reasonably elaborated, hefty enough to make a usefully airtight argument in its own right but at the end of the day it's not a form of publication. Short of reviews being peer-reviewed themselves, they're (again, ideally) a brand of highly informed opinion. So perhaps we should forget about the existence or nonexistence of dissenting opinions expressed by reviewers, IPCC section authors and editors and instead stick with the relative weight of available instances of substantiated dissent. That is to say, was any published research significantly falsifying the theoretical and observational underpinnings of the apparent effect we're having on climate left out of the IPCC reports? If not, where's the problem?
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16. OPatrick at 15:51 PM on 16 June, 2010
    I do wonder about Hulme's "Giving the impression that the IPCC consensus means everyone agrees with everyone else – as I think some well-meaning but uninformed commentaries do (or have a tendency to do)". Are there really commentators implying this, or is it just another example of what seems to be becoming a common 'there are those who exaggerate on both sides of the debate' type argument? I am not convinced that this argument is sound - for example I remember a year or two back when a Greenpeace quote about melting arctic ice was taken out of context to suggest some extreme alarmism. This reverberated around for some time even though it was patently and demonstrably a false accusation. Why would such a weak example need to be so prominently aired if such alarmism was so common? Can anyone find examples of this 'well-meaning but uninformed' commentary? I can't remember coming across any - most of the comments I read tend to be nuanced and if anything overstate the uncertainty.
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17. MattJ at 18:53 PM on 16 June, 2010
    Rapid correction of such distortion is not good enough: we need to create a powerful disincentive against dissemination of such disinformation, powerful enough to give the media reason to hesitate to spread it. As things are now, they have the opposite: powerful incentive to prostitute themselves to the purveyors of disinformation. As to how to create this disincentive, well, that is the hard part! All my ideas are still very undeveloped, such as bombarding the web-sites of offending media outlets with emails/posts with well-informed protest every time they spread the disinformation. But certainly any such well-informed protest will find articles like this Skeptical Science article very helpful.
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18. MrJon at 19:35 PM on 16 June, 2010
    This seems to be a rather silly argument that mostly demonstrates that the denialators don't understand the meaning of the word consensus. It always has and always will mean a 'majority opinion' - and given the nature of science and scientists reaching any kind of consensus is quite an achievement and is thus something that always needs to be considered seriously.
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    Moderator Response: great point. I hadn't bothered to look up "consensus" but here is it: "Consensus is defined in English as, firstly - general agreement and, secondly - group solidarity of belief or sentiment. It has its origin in a Latin word meaning literally to feel together." Also, you are so right about academics/scientists ever coming to consensus on ANYTHING! Consensus in a faculty meeting on the most trivial issue? Forget about it! (JB)
19. John Cook at 19:57 PM on 16 June, 2010
    UPDATE: I just received this email from Mike Hulme who granted permission to reproduce his reply to John B's comments:

    John B - The spirit of the paper was quite critical of the IPCC, this was not merely a neutral review

    Hulme – the paper is a review of 20 plus years of published literature which has examined the IPCC, its functions, governance, processes and impacts. Whether it is neutral, critical, or appreciative is a matter of reader’s judgement.

    John B - Second, while Hulme may not have said "the ‘IPCC misleads’ anyone" he did write that "Claims such as ‘2,500 of the world’s leading scientists have reached a consensus that human activities are having a significant influence on the climate’ are disingenuous." So the IPCC has not misled but is disingenuous?

    Hulme - I did not say or imply the IPCC has misled or was disingenuous. It is claims such as the caricatured one I offer which are disingenuous. It fact, the quoted comment by Kevin Rudd seems a good example of the precise sort of thing I was caricaturing. The precise IPCC AR4 statements ‘the warming of the [climate] system is unequivocal’ and “[most of the observed] increase in global average temperatures since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations” were not written and approved by 4000 scientists; they were written by small teams of experts, then reviewed by other experts and then approved by governments. Your commentators may call this pedantic, but I think it is important to point out how knowledge is assessed by experts and how headline statements are crafted. By the way, I think this is an entirely credible process, but people should not claim that it is more than it is.

    John B - Third, the point "That particular consensus judgement, as are many others in the IPCC reports, is reached by only a few dozen experts in the specific field of detection and attribution studies" is false. THAT is the main issue at hand. Hulme writes "The IPCC consensus does not mean – clearly cannot possibly mean – that every scientist involved in the IPCC process agrees with every single statement in the IPCC!" Well obviously, but nobody suggested that was the case (hello strawman).

    Hulme – but what, other than this – i.e., 4000 scientists concluded these specific statements, could Kevin Rudd’s claim imply?

    JB - But to suggest that only a few dozen out of the many thousands of scientists that worked on AR4 agreed with the key take home message, that human activities are having a significant influence on the climate, or were qualified to do so is silly. (also note Hulme's argument has shifted (we have seen this tactic before too); initially it was that only a few dozen people were qualified to make that inference, but now he is saying not every author agreed).

    Hulme – statements such as “most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations” is a very specific piece of knowledge crafting which I – and most other experts engaged by the IPCC - are not qualified to engage in at first hand. Or take another one – ‘it is very unlikely [less than 10% likelihood based on expert judgement] that the MOC [Meridional Overturning Circulation] will undergo a large abrupt transition during the 21^st century’. Most authors engaged by the IPCC are not qualified to participate in such specific knowledge crafting. The ambiguity in my original article emerges from the caricatured example of a ‘claim’ which I suggest is disingenuous [OED: ‘not straightforward or candid’], namely when I wrote ‘2,500 of the world’s leading scientists have reached a consensus that human activities are having a significant influence on the climate’. This is too general a claim for the specific point I was seeking to make about expert judgement and consensus-making. I should therefore instead have written in the original article, ‘Claims such as ‘2,500 of the world’s leading scientists agree that most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations’ are disingenuous”. This would have served my point much better – and in fact Kevin Rudd has made it for me And for the record .. I believe that the warming of the climate system is unequivocal and that most of the observed increase in global average temperatures since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations
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    Moderator Response: As usual, the readers / commenters at Skeptical Science are uplifting the quality of this conversation that is surprisingly subtle and multifaceted. Their responses and clarifications outdo anything I can muster, e.g., see David Horton at 07:50 AM on 17 June, 2010, NewYorkJ at 04:09 AM on 17 June, 2010, canbanjo at 02:11 AM on 17 June, 2010, and Stephen Baines at 08:30 AM on 17 June, 2010 below.
20. canbanjo at 22:47 PM on 16 June, 2010
    Am I getting this right...Hulme has said: "statements such as “most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations” is a very specific piece of knowledge crafting which I – and most other experts engaged by the IPCC - are not qualified to engage in at first hand." But Hulme also says: "I believe that the warming of the climate system is unequivocal and that most of the observed increase in global average temperatures since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations " Does this mean that Hulme is not qualified to engage in this at first hand, but in his unqualified opinion it is true? Clarifying what Hulme is saying is very important. It sounds like we now need to know the identities of all of the people that are 'qualified at first hand' to confirm the statement: “most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations”.
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21. OPatrick at 23:02 PM on 16 June, 2010
    There seems to be an assumption in Mike Hulme's argument, to some degree at least, that knowledge (or qualification to craft knowledge) is binary in nature. Either an expert has that knowledge or they do not. Either they are qualified to draw conclusions or they are not. Is it not a better reflection of reality that there are shades of grey in the depth of understanding each of those 2500 / 4000 / n scientists will have of any given point? There will be some whose expertise is concentrated almost entirely in the one narrow field of focus, others who may have a broader range, and presumably less depth, of specialisation. There may be some who have a great depth of understanding of a closely related field an so may well have good transerable knowledge and judgemnt. Many more may well not have the in-depth understanding to come to direct conclusions about a particular point but can a) say whether the conclusions fit with their own areas of expertise and with the broader picture of climate science and b) critically examine the scientific process behind the conclusions reached. This is how I would understand the concept of 'consensus' - as something like a web of mutually corroborating strands of evidence accepted and understood to varying degrees. Similarly, when a body such as the Royal Society endorses the position of the IPCC on climate change I think they become part of the consensus, not because they are claiming an exact understanding of each scientific point, but because they have confidence in the process and, hopefully, have scrutinised at least samples of that process to justify this.
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22. Tom Dayton at 23:16 PM on 16 June, 2010
    Heraclitus, I think that when Mike Hulme wrote that not everyone is qualified to make judgments "at first hand," he was using stringent criteria that are common among people at the highly knowledgeable end of the spectrum. He was using a magnifying glass at the extreme end of the spectrum.
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23. Philippe Chantreau at 01:07 AM on 17 June, 2010
    Indeed cabanjo. This is what happens when language appropriate for describing what we know of reality and how we know it (i.e. how assured we are of that knowledge) gets thrown into the "public debate" type of situation. It does not work. Hulme statements were perfectly reasonable, in accordance with what really happens in the IPCC process and in fact a good description of reality. Then they were high-jacked.
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24. canbanjo at 01:49 AM on 17 June, 2010
    Philippe, I normally find it very clear cut that deniers interpretation of events do not stand up to scrutiny unlike the articles on skeptical science. However in this case I cannot see how Hulme's statements could be clear to anyone - you can interpret them how you want to. Does "at first hand" mean something certain in the scientific community that laymen would not appreciate? I don't see how his response has clarified anything. So who are these people at the extreme end of the spectrum you mention?
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25. john mcmanus at 01:57 AM on 17 June, 2010
    I think Hulme said that although he is not a ranking expert in areas within climate science outside his niche he does feel well enough educated in climate science to judge the merit of papers others write and had no trouble agreeing with the vast majority of the scientists that write them. Only a specialist on pollen will get a paper concerning pollen in sediment published. Many , however, with other scientific foci will read such a paper and be qualified through mathematical and statistical training etc. to make a judgement on the value of the paper. John McManus
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26. canbanjo at 02:11 AM on 17 June, 2010
    John Mc, I understand and agree with that. But I thought the point about AGW theory is that it is a theory which is constructed from an array of disciplines - can there be a single discipline that has more authority or understanding level of the overall AGW theory than others? And if so (as Hulme seems to be saying) what is the significance of this? What point was Hulme trying to make when he wrote: "statements such as “most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations” is a very specific piece of knowledge crafting which I – and most other experts engaged by the IPCC - are not qualified to engage in at first hand." and what does 'knowledge crafting mean'? this is crazy.
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27. NewYorkJ at 04:09 AM on 17 June, 2010
    "Correcting and Clarifying Hulme and Mahony on the IPCC Consensus" It looks as much like a correction as it does a clarification. The original Hulme statement: "Claims such as ‘2,500 of the world’s leading scientists have reached a consensus that human activities are having a significant influence on the climate’ are disingenuous. That particular consensus judgement, as are many others in the IPCC reports, is reached by only a few dozen experts in the specific field of detection and attribution studies;" So only a "few dozen" experts (involved in the IPCC process?) have input into anything involving the influence of human activities? Hulme seems to "correct this" somewhat. "Third, it is the chapter lead authors – say 10 to 20 experts - on detection and attribution who craft the sentence about detection and attribution, which is then scrutinised and vetted by reviewers and government officials." So it's not a "few dozen" after all. Other things to consider: - The contribution from human activities is not confined to the "detection and attribution" section. It's also dealt with in the sections on radiative forcing and paleoclimate, for example. - Do contributing authors (not just lead authors) to the relevant sections have no say? - What of the many scientists who are co-authors on papers referenced in these sections but are not lead authors on those sections? - Aren't authors from other chapters reviewers as well? This gets at the "binary" approach Hulme is taking that Heraclitus refers to. Lastly, Hulme states: "And for the record .. I believe that the warming of the climate system is unequivocal and that most of the observed increase in global average temperatures since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations " But he's not a lead author of the detection and attribution section. How can his view possibly be relevant? (sarcasm) I think Hulme's original statement was poorly written and the correction insufficient.
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28. David Horton at 07:50 AM on 17 June, 2010
    I read and re-read the Hulme comments and the questions on this thread and I remain baffled. And then I read the use that Bolt (and I'm sure others) make of it and I remain angry. In any endeavour involving thousands of pieces of scientific work being combined there must inevitably be coordinators/editors, doing the combining. I was once the Editor of an Encyclopaedia. Was I an expert in every discipline incorporated in that work? Of course not. But I had advisory editors who were responsible for broad disciplinary areas, and contributing editors who put together particular topics, and they in turn were using the work of thousands of other researchers over (in my case) approximately 200 years of research. In my case, to say, oh well, this is the work of only 20 people, they could be biased, is just nonsense, and this seems to be what Hulme has done. Consensus is often referred to in climatology as if it is some mysterious process that takes place among a few conspirators in smoke filled back rooms at the UN. But consensus comes from the grass roots up. It comes from researcher X in America in one sub-discipline deciding how his/her work relates to past findings and to the work of researcher Y in Australia and researcher Z in, say, Greenland. Do the findings agree, yes, no, if no, why not? Is it because, ah yes, instrumentation is different, statistical treatment is different, geography is different, right, correct for that, ah yes, now they match, or, no, still not, what have we missed. Scientists, in short, don't just do a piece of work, in a vacuum, and put it out there, hoping that somewhere, someone, will see how it relates to other work. These relationships are a major feature of the way science is done. So indeed it is the work of thousands of scientists going into the IPCC reports, and the job of summarising has in effect been done. The only way this could not be true is if there was some fundamental disagreement - some scientists think CO2 is a ghg, some don't, hmm, what to do, I know, someone (a faceless bureaucrat who wants one world government) will make a decision at the UN as to which opinion is correct. I know this is what Andrew Bolt would like to believe. Probably does believe. Does Hulme believe this? Does he seriously believe that just a "few dozen" scientists with an agenda are creating global warming?
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29. Stephen Baines at 08:30 AM on 17 June, 2010
    I'll have to say that I also find Hulme's statements perplexing. I guess he's saying that 2500 people can't all be experts in attribution, or in species distribitions, or in ocean circulation or in GCMs or... That seems a very microscale view. What I find compelling about AGW is the fact that independent lines of inquiries conducted by individuals with widely divergent expertise converge on a common general picture of what's going on at present. So a specialist in bird migration does not need to be facile with radiative transfer models to partake in a broader "consensus" that climate is changing. I guess it all depends on which consensus one is talking about. Bolt has clearly taken him completely out of context. He seems to be exploiting Hulme's rather academic attempt at precision to suggest something Hulme does actually believe. It's ironic considering that Hulme is often keen to lay part of the blame for the controversy surrounding AGW at the feet of scientists' imprecise statements.
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30. Joe Blog at 09:02 AM on 17 June, 2010
    canbanjo at 02:11 AM on 17 June, 2010 I would assume hes meaning those qualified for attribution of anthropogenic radiative forcing/and its effect on climate/atmospheric/oceanic circulation... obviously pointing to evidence of climate change in itself is not proof of the cause(climate has at no stage been static) And this is the key, its no good saying ah ha, arctic ice is decreasing, thus it proves AGW. You have to be able to differentiate from natural climate oscillations, and show the mechanism by which additional anthropogenic radiative forcings are predominately driving climate changes in those regions etc.(lets face it... most of us arnt qualified to comment on line by line coupled atmospheric/oceanic climate models) I dont think he has written anything unreasonable. In all honesty, if i was debating this in public for the negative and someone pulled the whole "2500 ipcc" out, id be grinning like a Cheshire cat. There are so many ways you could attack that. From pulling up how many of the 2500 are actually in the hard sciences(some are government officials/bureaucrats) or pulling up various dissenting reviews/ and views. I think it is a disingenuous claim, and as Doug Bostrom pointed out, irrelevant. Its the science that matters. Not various demographics opinions on it.
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    Moderator Response: Nice try Canbanjo, but the IPCC authors/editors/reviews are not " government officials/bureaucrats" they are overwhelmingly if not entirely scientists. You can grin, but it is a fact. (JB)
31. canbanjo at 09:16 AM on 17 June, 2010
    Joe the key point here which Hulme has confused - is that on the one hand we are told that AGW theory is completely robust, which I take that to mean that one does not need to be expert in all details of AGW to come to the same conclusion that the theory is fundamentally robust. Hulme has cast doubt on that. WHO ARE THE EXPERTS HE REFERS TO? jo
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32. Joe Blog at 09:39 AM on 17 June, 2010
    canbanjo Well the basic radiative properties of co2 is totally robust(measured LW in various wave lengths at surface and TOA IS empirical proof of the various effect of the different GHG) And the instrumental record further backs this... but you still need to be able to differentiate and quantify the anthropogenic effects to rule out natural factors, negative feedbacks etc... at the moment there simply isnt enough high resolution climate data to do it that way.(a bit over 30 years really) But how this added radiative forcing will effect climate IS complex. How will it effect oceanic/atmospheric circulation/ which will effect evaporation/ which is effected by radiative forcing which effect radiative forcing, which could effect cloud, which effect planetary albedo etc. You could go on for ever. The way to figure this stuff out is to run high resolution line by line climate models. And try different scenarios. Which is not something yah can do with a calculator. And id be assuming the people he is referring to would be the likes of Gavin Schmidt, Hansen etc, that do run these models... But you would need to ask Mike Hulme;-)
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33. Joe Blog at 10:25 AM on 17 June, 2010
    "Moderator Response: Nice try Canbanjo, but the IPCC authors/editors/reviews are not " government officials/bureaucrats" they are overwhelmingly if not entirely scientists. You can grin, but it is a fact. (JB)" It was me, joe, not Canbanjo saying that, and i wasnt clear by what i said, how many of the 2500 are in social sciences, political sciences etc... Is what i mean by non hard sciences.(a bit disingenuous o me to claim non scientist/politician ) If i come up with a new idea for a compressor/expander, i dont think how well its going to work... i think hard about what can go wrong. And i think in a public debate the 2500 claim has so many ways you could attack it... i mean merely pointing out John Christy for example is included in the 2500. Or how many reviewed the attribution chapter etc... it really dosnt take long to find all sorts o ways you could attack this argument. It is an appeal to authority... with holes in it.
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34. Arkadiusz Semczyszak at 22:08 PM on 17 June, 2010
    "The AR4 report was indeed written, edited and reviewed by many thousands of expert scientists including the lead and contributing authors and the expert reviewers." professor Hans von "hot" supporter of AGW theory, the author III raport ICC: "Der eigentliche Sündenfall dabei war, dass sich der Rat entgegen seiner Regeln in seinen Aussagen nicht mehr allein auf wissenschaftlich legitime Quellen verlassen hat. Stattdessen hat er bei manchen Themen auf Zeitungsartikel und Berichte von Interessenverbänden zurückgegriffen. Schlimmer noch: Es ist der Eindruck entstanden, dass Umwelt- und Naturschutzverbände, aber auch wirtschaftliche Interessen direkten Einfluss auf Aussagen des IPCC nehmen konnten." - "The real sin is that the Council [IPCC] in support of their case has benefited not only from reliable sources, peer-reviewed research. Instead, the use of certain newspaper articles and reports of interest groups. Worse, there is a presumption that environmental organizations, but perhaps also economic interests have a direct impact on the IPCC reports. " "... normal scientific procedures are not only rejected by the IPCC, but… this practice is endemic, and was part of the organization from the very beginning. The IPCC is fundamentally corrupt. The only ‘reform’ I could envisage would be its abolition." (Gray, 2007).
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35. Arkadiusz Semczyszak at 22:09 PM on 17 June, 2010
    Hans von Storch - exactly
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36. JMurphy at 22:54 PM on 17 June, 2010
    Why do so-called skeptics find it so easy to believe in and trust (totally, without scepticism) one or two sources or scientists, against thousands of scientists and scientific reports ?
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37. canbanjo at 01:05 AM on 18 June, 2010
    JB, not sure why you said 'nice try' regardless of whether this was directed at Canbanjo or Joe Blog. May I suggest that a lot of the controversy surrounding the IPCC reports could be (and could have been) avoided by having a formal IPCC questionaire to be completed by all of the contributors and reviewers following publication of the final report. This would then enable simple statistical analysis to determine eg percentage who endorse the core findings of the report. The survey refered to in post 12 is better than nothing but considering the damage the denialists are causing we need much better amunition (facts) to clearly highlight the consensus.
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38. DrTom at 20:50 PM on 18 June, 2010
    Whew! What an awful time to be a climate scientist. The top is spinning down but it still wobbles through equilibrium on every rotation. Then it drops a bit and the climate deniers can absolutely get good data that there is no warming. Another half-cycle and it comes across equilibrium...but on the way UP, AGW scientists can absolutely qualify and quantify the shift. Both groups can obviously back-trend and find something. Humans are good at that. The only proof that anyone will ever accept...and many probably won't... is the Venus Syndrome. When climate forcing tips us into a continuous and irreversible feedback loop. What will the precursor to that look like? What marker will unequivocally show the end of our ability to stop our own extinction event and grasp that it has begun? I believe we are there, but I am not the Oracle of science. Yet there must be something specific we can recognize and leave debate mode for an attempt at survival.
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39. Steven Sullivan at 09:28 AM on 19 June, 2010
    canbanjo asserts: "Clarifying what Hulme is saying is very important. It sounds like we now need to know the identities of all of the people that are 'qualified at first hand' to confirm the statement: “most of the observed increase in global average temperatures since the mid 20th century is very likely [greater than 90% likelihood based on expert judgement] due to the observed increase in anthropogenic greenhouse gas concentrations”. " Not terribly. The science doesn't change. Hulme is mainly concerned with the third of three primary questions of climate change (as noted by by Philip Kitcher in his June 4 review of recent books, including Hulme's in Science): "First is the issue of whether human activities, specifically actions that increase the emission of greenhouse gases, are contributing to a signifi cant average warming of Earth. (As all the expert authors point out very clearly, there is no suggestion that the temperature of every region will rise during the next decades.) Second are questions about the probabilities with which various phenomena (complete melting of ice sheets, for example) will occur and about their consequences for human beings and other species. Third are considerations about what might be done to halt (or even reverse) the warming and to limit the damaging consequences. Hulme emphasizes the complexity of the third set of issues" I think the main lessons of this incident are for Hulme -- think about how your words may be (mis)used -- and the 'denial' community -- be careful what bandwagon you leap on.
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40. canbanjo at 10:57 AM on 19 June, 2010
    Steven, I also have not made my points clearly enough. its not me that needs persuading. I am on the 'frustrated at the science communication failure' bandwagon. i would like to do something about it.
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41. canbanjo at 00:58 AM on 20 June, 2010
    This is a good site: http://www.eecg.utoronto.ca/~prall/climate/index.html including: http://www.eecg.utoronto.ca/~prall/climate/climate_authors_table.html
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42. Doug Bostrom at 04:49 AM on 21 June, 2010
    Speaking of leaky journalism, "Africagate," "Amazongate" are officially decommissioned by their publishers, both of whom relied on Jonathan Leake to lead them into credibility-sapping embarrassment. Hopefully the newspapers lead astray will see the pattern. Climbdowns covered here at Real Climate.
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43. notcynical at 12:20 PM on 21 June, 2010
    Mike Hulme: Giving the impression that the IPCC consensus means everyone agrees with everyone else – as I think some well-meaning but uninformed commentaries do (or have a tendency to do) – is unhelpful; it doesn’t reflect the uncertain, exploratory and sometimes contested nature of scientific knowledge. John B at 17:01 PM: Rudd simply said "this is the conclusion of 4,000 scientists". Well it is. This is demonstrably and irrefutably true. Q.E.D.
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