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Rob Honeycutt at 11:02 AM on 29 May 2013The 5 characteristics of global warming consensus denial
" I'm at a loss as to how this is 'nitpicking the definitions.'"
You don't seem to agree with how the categories were defined. So I'm suggesting you create your own and perform your own survey. If you think the way Cook13 was crafted has unduly influenced the results, then I think everyone would be extremely interested to see you show how. And I mean that genuinely.
"You also felt it was worth a certain amount of money gotten from your readers."
What are you referring to? Are you talking about the money raised so that John could make the paper open access?
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Brandon Shollenberger at 10:21 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Rob Honeycutt, I'm at a loss as to how this is "nitpicking the definitions." You and your associates felt examining a consensus was worth a great deal of effort. You also felt it was worth a certain amount of money gotten from your readers. If examining something was worth that much, surely it is worth stating what that something is.
Glenn Tamblyn, this site has posted many critiques of papers. Why should I refrain from doing the same? As for replication, you guys spent a great deal of time on this study. It is unreasonable to suggest nobody criticize your paper without having spent an equal amount of time working on an issue. That is especially true given that I am but one person, and you were 24.
dana1981, you have suggested exactly that. I've even quoted you as suggesting exactly that. While I can understand you may have forgotten having done so, it is unwise for you to state it so categorically. My statement is fairly easy to verify.
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Tom Curtis at 10:19 AM on 29 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Barry @225:
1) To read categories (2), (3), (5), and (6) as consistent (and hence exclusive) even qualitatively, you must take (2) to include all papers that explicitly state anthropogenic factors as a cause of warming, but do not minimize or otherwise indicate the impact is minimal. If you do not, you can have papers rated as both (2) and (5) or (6). Likewise (3) must also be taken as excluding papers which minimize the anthropogenic contribution. Ergo saying that doubling CO2 causes a 1 C no feedback warming, but a 0.5 C warming after feedbacks would preclude an abstract from being classified as (2) or (3), and would pretty much mandate its classification as (5). However, while you can assess the meaning of ratings (2)-(6) in isolation, doing so excludes relevant information. The description of ratings (1) and (7) makes it clear the benchmark for "minimizing" or "not minimizing" is the 50% mark.
On that basis, a phrase like "... anthropogenic factors are the major cause of recent warming" would get the abstract rated as affirming the consensus. In contrast, a phrase like "... anthropogenic factors are a major cause of recent warming" would downgrade it to the neutral bin in that it is possible with that phrasing that natural factors are equal or larger causes.
2) Because the evaluation of abstracts rated as (2) or (3) are based mostly on qualitative terms, it is likely that they will show more false positives than abstracts rated as (1). That does not justify distorting the meaning of the categories to minimize false positives. It is important to avoid false positives (and negatives); but it is more important that the characterization of the consensus be consistent across categories. Therefore arguing from the fact that the qualititive assessments in categories (2) and (3) will lead to false positives to the conclusion that the definition of the consensus differs for those ratings compared to category (1) puts the cart before the horse. The proper way to proceed to to determine the meaning of "affirms the consensus" from the available data from all rating categories and related comments; and if you do the position I am defending naturally follows. You then go on to assess the likely rate of false positives and/or negatives.
Because it is desirable to be conservative in these assessments, the way to avoid false positives is to be cautios in the ratings. Given the difference between the abstract ratings and the self ratings, I do not think there is any doubt that the Cook et al rating team were conservative. While there are likely to be false positives among the ratings, they are far exceded by false negatives. Arguments that the self rating data do not confirm that false negatives exceeded false positives depend essentially on ignoring what we know about the consensus of scientists and publication rates from other sources.
3) Turning to your first example, given only the data you provide, I would indeed have rated the paper as (3), and it would have been a false positive. It would also be an odd example, with the stronger result hidden in the body of the text. It would be rather like a newspaper article leading with "Dog growls at man" and mentioning in the last paragraph "assassination attempt on president". The reason for classifying the abstract as (3) includes the presumption that stronger, more interesting results will be mentioned in the abstract.
4) Turning to your second example, I would have classified it as neutral (4); and did so before I read the follow on part of the sentence.
5) Instead of checking category results, try doing the self rating excercise for 100 plus papers and check your level of agreement on endorsements with the Cook et al ratings. I am up to 35 so far, with complete agreement using my interpretation of what it means to confirm the consensus. I know from examples presented elsewhere that there are some abstract ratings I disagree with; but given that 12,000 abstracts were rated, it is unsurprising that there are some errors. You cannot check the validity of the rating system by picking out one or two errors; but only by rating a significant sample.
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Rob Honeycutt at 10:14 AM on 29 May 2013The 5 characteristics of global warming consensus denial
I'm kind of thinking this is going to end up being like all the hockey stick graphs. Lots of complaining about methods and data and such. But never, ever, will the "skeptics" do their own research on this one, simply because their results would never support their preferred conclusions. And that is what makes them fake skeptics.
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dana1981 at 10:02 AM on 29 May 2013The 5 characteristics of global warming consensus denial
I've never suggested comparing Categories 6+7 with 1. Category 7 is comparable to 1, and 6+7 are comparable to 1+2.
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Glenn Tamblyn at 09:40 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon, let me second Rob's suggestion
Cook et al 2013 is a scientific paper. The time honoured method of critiquing or checking a piece of science is through replication. Someone seeks to replicate the earlier work. All other approachs, comments on blogs, self appointed 'auditors' etc are just a farce by comparison.Replicate the study Brandon. Or even better, design your own study method and go for it.
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scaddenp at 09:37 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
William, and yet the modellers have done what you suggest as the links provided show, and funnily enough do just as you propose as reading the papers would show you. "The appropriate balance" being of course the forcing set used which each model run explicitly shows you. "I would not automatically assume things are done correctly" - well good, but have you bothered to read how in fact it was done? The fact that you get similar results from completely different models, working in independent groups worldwide should at least suggest that maybe they are on track. Are you looking for the truth or looking for a rationalisation for inaction? If the former, then we are here to help - quote science papers in discussion though. If the later, then I would suspect ideological problems with proposed solution. Reality v. ideology. Hmm.
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Rob Honeycutt at 09:27 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon... Instead of nitpicking the definitions (I would hold that no matter how Cook13 had defined it, you would still be nitpicking) why not write your own categories, do your own research and see what results you get?
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Rob Honeycutt at 09:24 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon... You might note there is nowhere in Cook13 where it states that only 10 papers out of 12,000 reject AGW. That would be as equally an unsupportable statement as saying only 65 papers endorse AGW.
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Brandon Shollenberger at 09:22 AM on 29 May 2013The 5 characteristics of global warming consensus denial
shoyemore, I was less clear than I should have been. The definition I'm referring to is not the definition of the word "consensus," but rather, the definition of the specific "consensus" being examined by Cook et al.
John Hartz, given I believe this issue is an important one, that could only serve to encourage me. I would like discussion to continue.
dana1981, you yourself have suggested comparing categories 6 and 7 with category 1. Given category 6 has as much (or rather, as little) quantification as category 5, what makes my inclusion of category 5 so much more illogical? Why should it be okay to include category 6 but not category 5?
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Tom Dayton at 09:17 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
William Haas, the construction of the models is described in great detail in the appropriate places that you easily can find by following the provided links and merely clicking around a bit. Your extreme skepticism is unconvincing since it is based on your ignorance that is due purely to your failure to bother reading.
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dana1981 at 09:01 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon, there are several ways your argument could be interpreted since frankly it's totally illogical, comparing every single implicit and explicit rejection/minimization (Categories 5-7) to explicit endorsements with quantification (Category 1). If you'd prefer, we can describe it as a misrepresentation of our survey, since you're comparing incomparable categories.
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rockytom at 09:00 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Rob, the reason "they" don't do the research is that "they" can't substantiate "their" comments by factual information that research would provide. It is enough for the prevaricators and deniers to state an opinion. Facts are not important!
Kudos to John and the Team!
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William Haas at 08:37 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
Dikran Marsupial, 1850 to 2012 is much more challenging because of the changes in direction. To be of any value such simulations have to be appropriated calibrated and contain the appropriate balance of human caused and natural factors. A simple model has been used but how has it been calibrated with reality. I would not automatically assume that things are done correctly. In quality, the projections do not look much like what has been happening over the past century and a half.
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John Hartz at 08:34 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon:
As they say, "If the shoe fits, wear it."
BTW, The more comments you post, the more likely that John Cook will write a sequel.
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Rob Honeycutt at 08:27 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon... You know, with the amount of time you've spent trying to discredit Cook13 you could have actually done something useful and started up your own research project to see if you can replicate Cook13. You know, that would be the "skeptical" thing to do.
My only takeaway, at this point, can be that you folks don't really believe the position you're putting forth. It seems the only thing that is important to you is to "manufacture doubt" (to borrow a phrase) rather than test the ideas you have.
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scaddenp at 08:05 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
William, you are asking the wrong question. Try "do models have skill?"
See the FAQ at Realclimate for detail on this.
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shoyemore at 07:52 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Brandon #2,
What is wrong with the dictionary definition?:
1. majority of opinion: The consensus of the group was that they should meet twice a month.
2. general agreement or concord; harmony.
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tcflood at 07:45 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
In order to better understand this paper, I need to ask a couple of low-level questions.
How does a “simple” climate model give uncertainties that are more meaningful than a more complex model?
They say that a certain amount of uncertainty comes from climate sensitivity. I thought CS came from the calculation rather than being an input parameter?
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Brandon Shollenberger at 07:22 AM on 29 May 2013The 5 characteristics of global warming consensus denial
This post says:
This technique of unrealistic expectations was illustrated in another blog post claiming that only papers which quantify the human contribution to global warming count as part of the consensus.
Referring to a post which quotes arguments I have made. As I am a target of this criticism, I feel I am obliged to respond. My response is twofold. 1) Where in that post, or anywhere else, is it claimed "only papers which quantify the human contribution to global warming count as part of the consensus"? As far as I can tell, that post never defines the consensus. It merely (and accurately) says:
When stripped down to the bare truth, the actual number of studies in the Cook sampling that can be said to endorse the position that human activity is responsible for most of the experienced global warming is — get ready for this (drum roll …) — sixty-five.
That doesn't say only 65 endorse the "consensus." It says only 65 endorse a particular position. That particular position may or may not be the "consensus."
2) There is no clear, much less explicit, definition of "consensus" in the Cook et al paper. None was provided on Skeptical Science either. Obama's tweet about this paper, which Skeptical Science has used for publicity, describes the consensus found by this paper as something it could not possibly be. It's cheeky to criticize people for using a different criterion for the "consensus" when you never bothered to provide one of your own.
Unless or until a clear definition for the "consensus" is provided, it is silly to criticize people for using a different one.
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Dikran Marsupial at 05:48 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
William Haas The IPCC already did pretty much that, for example the
20c3m experiments are forced with historical green house gas forcing as well as the time varying ozone, sulfate, volcanic aerosols, and solar output for the 1900-2000 period. This analysis uses 20th century experiments from 10 models. The B1, A1B and A2 experiments are forced with a predicted green house gas forcing scenario for the 2000-2100 period. (www)
so we have the 1900-2000 period to judge the model's performance. IMHO it is hubris to think that the worlds leading climate modellers didn't think to do this, and hubris2 not to bother checking first before posting.
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DSL at 05:36 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
William, is Jones et al. 2013 not good enough?
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william5331 at 05:34 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
Maybe we should forget climate change. (I'm kidding)
http://mtkass.blogspot.co.nz/2010/10/forget-climate-change.html
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William Haas at 05:33 AM on 29 May 2013Uncertainty no excuse for procrastinating on climate change
If the models are wrong the subsequent analysis will be of no value. I would like to have seen them use a starting date for their simulation of 1850 so we can compare what actually happened with what their simulation says should have happened. The real world should be a combination of greenhouse gas causes and other causes. If the simulation cannot accurately predict what has actually happened between 1850 and now then its predictions for beyond now are of no value.
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shoyemore at 05:29 AM on 29 May 2013The 5 characteristics of global warming consensus denial
Congratulations to John and his team, again.
I think future historians (let's hope the are some around long term :)) will highly value this contribution to "the science of doing science", or "the science of science interfaced with politics" in the early 21st century. Meta-science?
It's immediate practical contribution is to de-bunk the fake-sceptic argument (made now mostly by politicians like Mitt Romney) "We can't do anything until the scientists make up their mind".
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JasonB at 02:34 AM on 29 May 2013Cherrypicking to Deny Continued Ocean and Global Warming
MA Rodger,
I don't think Lindzen and Spencer disagree that "a doubling of atmospheric CO2 levels would (by itself without feedbacks) cause a little over 1 C of warming". Spencer has even posted articles trying to "educate" the less-informed "skeptics" on the reality of the greenhouse effect. As CBDunkerson said, they rely on "undefined negative feedbacks" to support their beliefs in a low CS.
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DSL at 00:02 AM on 29 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
What gets me about this whole rigmarole is that in publication, almost no one actually questions the attribution studies that have been done. There aren't actually a large number of people working on this question. As CBD points out on another thread, "Actually, I am not aware of any 'legitimate scientists' who disagree that a doubling of atmospheric CO2 levels would (by itself without feedbacks) cause a little over 1 C of warming." Solar studies are virtually uniform in their pointing out that solar variation is either an insignificant and/or negative forcing for the trend of the last fifty years. Those two pieces of evidence alone should be enough to convince any scientist working in or near climate that anthro is the primary forcing behind the trend of the last fifty years.
The range of responses to the Cook study is telling. The un-engaged mainstream either accept it or don't, without investigation. Few of those aware of the attribution research quibble with the presentation of the study, because they know the above: the dominance of the human factor is pretty obvious. Now, who are these people who quibble? Why do they quibble? For some, it's obviously the same reason they quibble over Mann's "hockey stick" and the Marcott reconstruction. The message is simple and rhetorically powerful in the public domain, and undermining that message is job no. 1 (literally for some--Watts, Singer, Monckton, et al.). For others, I don't know . . . follow the leader, I guess. It's rather obvious, though, that if this level of scrutiny were applied to Soon & Baliunas (2003), Scafetta's work, or Chilingar et al., then there'd be fewer in the ranks of doubters and many more angry at the publication standards of petro journals (e.g. Energy & Environment). -
MA Rodger at 23:52 PM on 28 May 2013Cherrypicking to Deny Continued Ocean and Global Warming
CBDunkerson @107.
You appear to be setting far higher standards for a "legitimate scientists" label than I would accept. Consider a scientist like say Lindzen who genuinely believes in his unorthodox scientific position despite the overwhelming evidence supporting the orthodox position. He will not balk at challenging that evidence, would not think twice at throwing light into dark corners that other scientists who accepts the veracity of the available evidence would never dream to disturb. While those dark corners continue to exist, the likes of Lindzen continue to do science a service, of sorts.
For instance, take Spencer & Bradwell 2008. Is this not legitimate science produced by a contrarian?The problem with the likes of Lindzen & Spencer is not the science. It is their behavour ouside the science that is unacceptable, things like Lindzen's presentations to non-scientific audiences in which he makes assertions he would never get away with within the science. The same goes with Spencer's book.
This extra-scientific comment from contrarians is part of the fuel for opinions like that presented by matzdj @102. 100% of the evidence supports AGW? "That can't be," writes matzdj.
Well surely, if AGW is the correct theory, bar the science misinterpreting evidence (available evidence won't always and unfailingly point in exactly the correct direction), I say, "It can be. Indeed, it must be!" -
CBDunkerson at 21:08 PM on 28 May 2013Cherrypicking to Deny Continued Ocean and Global Warming
matzdj wrote: "Both sides do have legitimate scientists on them (more on the CO2-is-the-ogre side), but there is no legitimate way that every statement that either side makes can be wrong."
Actually, I am not aware of any "legitimate scientists" who disagree that a doubling of atmospheric CO2 levels would (by itself without feedbacks) cause a little over 1 C of warming. The evidence on that became overwhelming decades ago. Rather, the handful of 'skeptics' claim that undefined negative feedback effects will reduce this warming (and the known positive feedbacks) and that the observations of warming in line with rising CO2 over the past century must therefor have been caused by some other undefined factor. That's getting sufficiently implausible to start straining the "legitimate" scientist label on its own, but that is the extent of current disagreement. No one disputes the CO2 greenhouse effect except non-scientists whose views have no foundation in reality... and which therefor can indeed 'always be wrong'.
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JasonB at 20:23 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
Jason, can you define, precisely, the consensus position you rated under? If there are caveats regarding the 7 ratings, can you also indicate? I want to understand what you did.
I'll do you one better, I'll show you the abstracts I rated as 3 in addition to the one shown above.
1. http://www.sciencedirect.com/science/article/pii/S1359431106001980
I rated this as "3. Implicit endorsement" because the first sentence is "Climate change induced by global warming is a result of an excess of energy at the earth’s surface due to the greenhouse effect." My reasoning was that the author was unequivocal about the fact that global warming is due to the greenhouse effect, and since man is responsible for the enhancement of the greenhouse effect, I decided that it implicitly endorses man's responsibility.
Cook et al rated this as "4. Neutral".
2. http://onlinelibrary.wiley.com/doi/10.1002/asmb.530/abstract
I found this one to be tricky but ended up rating it as "3. Implicit endorsement" because the way the paper discusses "‘clean up’ (e.g. reforestation)" and "irreversible emissions" suggested to me that they were taking for granted man's effect with no indication that they thought anything else might be involved.
Cook et al rated this as "2. Explicit endorsement".
3. http://www.inderscience.com/info/inarticle.php?artid=4830
I rated this as "3. Implicit endorsement" because the paper talks about the economics of different greenhouse gas emissions abatement rates in the context of interactions between global climate change and the world economy, implying (to me) that they take for granted the relationship between emissions and climate change (discussing abatement rates would be pointless otherwise) with no indication that they thought anything else might be involved.
Cook et al rated this as "4. Neutral".
In each case, I felt that the authors were making a link between AGHGs and global warming and none of them indicated there was any other factor involved at all, so your four categories of ">50%", "dominant", "significant", or "some" don't apply at all — there is no clue in any of those abstracts that anything other than man is causing global warming.
Can you help me understand this? If a paper was rated as neutral, it was not included in the tally. Is that how this supposition is figured?
1,342 papers were rated by their authors as endorsing the consensus, while 39 were rated by their authors as rejecting the consensus. Hence the rate of endorsement was 1,342/(1,342 + 39) = 97.2%. If half of the "endorsement" papers were mistakenly rated as endorsing the consensus when they should have been neutral, the rate of endorsement would have been 671/(671 + 39) = 94.5%. (We are assuming here that no author is going to mistakenly rate their paper as endorsing the consensus when it actually rejects it, which seems to be reasonable given the motivation to draw attention to a "contrarian" paper that's passed peer review and the availability of levels 5, 6, and 7.)
Any case, that is not the argument I'm making. I need to know, definitively, the consensus position Cook et al were rating under. Is it this?
The consensus position Cook et al were rating under was very clearly spelled out in the paper: "that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW)"
Given they rated two papers as neutral that I thought were pretty clearly implicitly endorsing that very statement, it seems they used a very strict interpretation of it.
Because if the original Authors rated under the lower bar (any anthro influence) for 2 and 3, then the comparative results are not as robust as indicated.
That's a big "if", and one for which you are yet to provide any evidence whatsoever.
Why would authors rate under a lower bar? Why would they rate their own paper as "endorsing" if, in fact, it assumed or stated a minor human influence, when levels 5 and 6 were available for them to categorise their own paper? After all, the authors were working with their entire paper plus their own knowledge of what they actually meant by what they wrote, so if in their view their paper said nothing to imply something other than humans was the main cause in their entire paper, how can you argue that their paper is "actually" not endorsing the consensus?
Regarding Cook et al's ratings, if you feel that mistakes were made, feel free to check them yourself. They're completely open. There's no point discussing "potentialities" when you can actually check the reality. If you're just going to check a random subset, remember to count how many you check so we can assess the significance of your findings.
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barry1487 at 16:56 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Jason, can you define, precisely, the consensus position you rated under? If there are caveats regarding the 7 ratings, can you also indicate? I want to understand what you did.
I upthread asked for peopel to precisely define what they think is meant by 'consensus position' in Cook13, relative to rating options 2 and 3. I was interested to see if their was conformity or not.
a) >50% human influence
b) dominant human influence
c) significant human influence
d) some human influence
These are four ways that I can think of to legitimately interpret the consensus position for ratings options 2 and 3. When I did the public survey, I applied criterion d) (I missspoke earlier upthread). I am unsure as to what degree Cook et al would have applied to ratings 2 and 3.
As Tom mentioned before, in order for the original authors' level of endorsement to drop to 94.5% — a figure I would still consider overwhelming — you would need to believe that half of the original authors mistakenly assessed their papers as endorsing the consensus when they should have been rated as neutral.
Can you help me understand this? If a paper was rated as neutral, it was not included in the tally. Is that how this supposition is figured? Any case, that is not the argument I'm making. I need to know, definitively, the consensus position Cook et al were rating under. Is it this?We examined a large sample of the scientific literature on global CC, published over a 21 year period, in order to determine the level of scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW).
Because if the original Authors rated under the lower bar (any anthro influence) for 2 and 3, then the comparative results are not as robust as indicated.To put it simply, and assuming;
1) Cook et al rate with the consensus of >50% anthro as the standard for all ratings bar neutral. They get 97% endorsement.
2) Original Authors rate 1) same as Cook et al, but rate 2) and 3) as endorsing any amount of human influence of global warming. 97% endorsement, also.
You don't see a problem with this potentiality?
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JasonB at 15:56 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
barry,
Out of interest I compared the ratings I gave to the ten papers in the original exercise with the ratings that Cook et al gave.
The paper that I rated as a 1, Cook et al also rated as a 1.
The five papers that I rated as a 4, Cook et al also rated as a 4.
That leaves four papers, all four of which I rated as 3's. Of those four, Cook et al rated one a 2, one a 3, and two as 4. So of the five that I rated as endorsing the consensus, Cook et al only counted three as endorsing the consensus, applying a much stricter test than I did for the most part.
The original authors, on the other hand, had a higher endorsement rate than I did — my average was 3.3, the original authors' average was 2.8. However, knowing that the original authors were assessing the entire paper explains why so many of the 4's were recategorised, such as this one that I (and Cook et al) rated as a 4 based on the abstract, but who's very first sentence in the introduction of the actual paper was:
The anticipated increases in greenhouse gases, especially carbon dioxide, in the atmosphere are predicted to raise temperatures by about 2.1 to 5.0 C globally within the next 100 years (Wigley and Raper, 1992; IPCC, 2001).
Note that the 16% disagreement was over all seven levels of endorsement category. In my case, the paper I rated as 3 that Cook et al rated as 2 would be counted as a "disagreement", even though it would have no impact on the final endorsement vs rejection percentage. I suspect that when lumping the 1+2+3 and 5+6+7 categories together the level of disagreement would have been much lower. And the two that I rated as 3 that Cook et al rated as 4 would actually lower the final endorsement percentage.
I'm not especially concerned that they had to revisit and discuss the interpretations of the criteria as real-world examples were encountered so they could reach a consensus on how the criteria should be applied; I've encountered exactly the same issue when marking exams with written answers. I'm also not concerned that the original authors may have individually been applying a slightly different interpretation, for the same reason that nobody seeks to rigorously define exactly what "beyond reasonable doubt" means to jury members. When you get large numbers of people responding, unusual interpretations tend to cancel out.
All these factors mean is that there is an error margin when it comes to the precise level of endorsement in the literature but nobody should be getting hung up on the precise percentage. The fact is that the results are overwhelming. As Tom mentioned before, in order for the original authors' level of endorsement to drop to 94.5% — a figure I would still consider overwhelming — you would need to believe that half of the original authors mistakenly assessed their papers as endorsing the consensus when they should have been rated as neutral. Now, some may have made a mistake, but to assume that half did beggars belief, and even if they did it still wouldn't change the take-home message.
I have seen statements here and there to the effect that such-and-such is the final nail in the coffin of "CAGW" and that there is a growing opposition within the scientific community to the IPCC's statements or that a "silent majority" of scientists are sick of IPCC alarmism and are gradually coming out of the woodwork to speak out against the "corruption" of science, but there is absolutely no evidence of this, and Cook et al actually shows the endorsement growing with time. If that belief was reflected in reality then we wouldn't need to be arguing over whether "humans are causing global warming" means something different to "global warming is caused by humans", there would be a lot more papers unambiguously rejecting the consensus. No matter which way you cut it, that category is tiny, and that's before we even get into the nitty-gritty detail about the actual quality of those papers.
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gpwayne at 15:38 PM on 28 May 20132013 SkS Weekly Digest #21
Message to John Hartz: great work, but you really need to run your posts through a spell checker - examine the first paragraph please...
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barry1487 at 15:05 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
To elaborate on the argument of 'overlap' in the ratings - there may be no overlap in the mind of each rater, as each interprets the set differently, but the total results may include plenty of overlap because of each rater interpeting differently. I note that there was a considrable amount of disagreement on rated abstracts for Cook et al, who then got to discuss and amend their ratings according to clarified criteria.
Initially, 27% of category ratings and 33% of endorsement ratings disagreed. Raters were then allowed to compare and justify or update their rating through the web system, while maintaining anonymity. Following this, 11% of category ratings and 16% of endorsement ratings disagreed; these were then resolved by a third party.
Isn't this strongly suggestive of problems with definitions? One third of endorsement ratings disagreed, and Cook et al had been discussing the criteria during the first phase of rating. Even after the second phase there was still 16% disagreement. There was no such process of clarification for the self-rating Authors. Are these not fair grounds to wonder if the comparative results are not as robust as indicated?
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JasonB at 14:50 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
s_gordon_b,
Your entire argument that the abstract of the paper is an example of the spin you're referring to is based on the claim that "the consensus" referred to in the abstract is not the IPCC statement (stated explicity in the introduction) but rather a vague claim that humans are merely a signficant cause of global warming, and your entire evidence for that is the simple fact that categories 2 and 3 are rated as supporting the consensus.
In other words, you believe that categories 2 and 3 cannot be interpreted as endorsing the IPCC's statement of consensus and the only way to claim that they do is by watering down "the consensus" that is being referred to.
This belief of yours, however, has not been demonstrated at all. Where are the examples of papers that cannot be claimed to endorse the IPCC's consensus that were nevertheless rated by Cook et al as category 2 or 3 papers? The descriptions of each category cannot be read in isolation, independently of the other categories that were available, and they cannot be read without examining how they were actually applied.
You seem to believe that categories 2 and 3 were "catch-all" default categories that anything that remotely appeared to endorse the consensus was lumped in to. This is not the case. As a concrete example, here is one of the papers that I rated as a 3 (implicit endorsement) during the first exercise, well before any tiresome semantic argumentation here about how papers should have been categorised, or whether "humans are causing global warming" means something different to "global warming is caused by humans" (!):
Methodology for adapting metal cutting to a green economy
The advent of global warming, as attested by the Intergovernmental Panel on Climate Change (IPCC), has serious ramifications for various facets of the human endeavour. Manufacturing is one such activity that is poised to undergo significant changes for curbing green-house gas emissions. This paper presents schemes for reducing the energy consumed in machining and grinding operations — the workhorses of any typical manufacturing set-up. These schemes are based on the mechanics of the metal cutting process which have been well studied over the years. Besides lowering the energy drawn from national grids, such schemes will pave the way for improved energy-efficient manufacturing processes. In the foreseeable future, alternative fuel systems to power manufacturing processes together with both newer operations and schemes, such as those outlined in this effort, would have a positive impact on the energy consumption of the manufacturing sector.
Searching for the paper in the database showed that Cook et al also categorised this paper as a level 3. The paper is like many others in this category — it is not about the causes of global warming, it is one of many about the impacts or (in this case) steps we can take to mitigate the impacts. Yet it quite clearly accepts the IPCC's findings. Indeed, it's the motivation for the paper. This is the kind of paper that you would not want counted as endorsing the consensus because it doesn't say "humans are responsible for >= 50% of global warming" while at the same time you do want counted papers (such as this) which don't say "humans are responsible for < 50% of global warming" and yet get categorised as level 5 by Cook et al:
I think you've made a fundamental error here. For a paper to unambiguously support the IPCC et al. consensus, it does indeed have to fall into category 1. But for a paper to unambiguously reject or deny it, it only has to fall into category 5, 6 or 7. That's 0.7 of 11,944 papers = 84 (maybe a few more, judging by the responses to some to the queries Popular Technology sent to known anti-AGW scientists whose papers had been rated). So the proper comparison, it seems to me, is 64 vs 84 or 64 out of 148 explicitly, unambiguously endorsing vs rejecting the IPCC consensus.
No. The categories are symmetric. If a paper numerically quantifies human responsibility, it's either a level 1 or a level 7. If a paper makes an explicit statement about human responsibility without numbers, it's either a level 2 or a level 6. If a paper implies or assumes causation, it's level 3 or level 5. You can't count only level 1 and compare it with level 5 + 6 + 7. If you don't trust the implicit categories, fine — ignore them. Measure 1 vs 7, or 1 + 2 vs 6 + 7. And then wonder why the figures come out so similar anyway.
Your mistake is to assume that papers in categories 2 and 3 must be ambiguous, and that unambiguous papers must be category 1. That is not the case. To exclude papers like the one I showed above would not result in an accurate reflection on the level of support for the IPCC consensus within the scientific literature.
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barry1487 at 14:08 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
I am not 'hostile,' for the record.
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barry1487 at 14:08 PM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Tom,
...several cues require us to give "endorse AGW" and "reject AGW" the same meanings where ever they occur in the list of categories. Of these the most important is that if you do not, if you allow "endorse AGW" to mean "endorse the claim that humans have caused most of recent warming" in (1), but "humans have caused at least some part of recent warming" in (2) and (3), then abstracts can logically belong to both categories (2) {or (3)} and category (7) at the same time. Given that the categories are clearly intended to be exclusive, it follows that if "endorse AGW" and "reject AGW" can be interpreted in a way that makes them exclusive it they should be; and that any interpretation that makes them non-exclusive is a misinterpretation. If follows that "endorse AGW" and "reject AGW" must be given the same meaning whereever they occur in the rating system, and that the difference in ratings for endorsements and rejections is a difference not in the level of endorsement (or rejection) but in the clarity of the endorsement or rejection in the abstract.
Several critics of the consensus have bizarrely criticized the paper both on the grounds that both the ratings at different level vary the meaning of "endorse AGW" and that the ratings are inconsistent due to overlap. They do not appear to recognize that by doing so they make their criticism inconsistent. Specifically, they make it clear that they show their criticism to be based on a hostile, out of context interpretation of the ratings and therefore irrelevant.
Are you saying that because 1 and 7 are quantified, that it follows that 2, 3 5 and 6 must reflect that quantification (>/<50% human influence)?
If ratings 2, 3, 5 and 6 are perceived as purely qualitative, then they can be read as exclusive. But, as a supposed reflection of the following paper, they might not be so. 2 and 3 get a tick if there is any suggestion that the globe has warmed/will warm due to human activity. 5 and 6 get a tick even if warming has been acknowledged, but the abstract 'minimises' (qualitatively) the human contribution.
2 and 3 might get a tick if the abstracts contain a statement like "it is expected that increases in atmospheric concentration of CO2 from industrial emissions will cause the lower atmosphere to warm," but the paper's conclusion may be that human activity has contributed 30% to the total warming. This is why I want to know if Cook et al rated 2 and 3 with the >50% AGW in mind (with the original Author in this example self-rating by the lower standard of AGW to any degree). Same rating but different criterion. That's an issue, how much of an issue is difficult to say.
An example of the same potential disjoint for ratings 5 and 6; an abstract may say, "our results indicate a smaller contribution to global warming from human activity than our previous study," but only in the body of the paper do you discover that this contributon amounts to, say, 53% instead of 59%. Qualitatively, in the abstract, AGW has been 'minimised'.
Imagining that there is no more information in the abstract than what I have invented in bold, how would you rate the last one, Tom?
(When I have time again I'll check out relevant category results, and maybe compare to full version papers if possible)
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Bob Loblaw at 12:27 PM on 28 May 2013Medieval Warm Period was warmer
WIlliam Haas: "There is proxy data that shows that for a specific location, temperatures were warmer during the Medieval Warm Period then they are today and man's contribution of CO2 to the atmosphere could not have played a part."
I have direct, anecdotal evidence that it was warmer in my back yard the week before last than all the global warming scenarios ever created predict for the next 100 years. And I'm sure CO2 was not the cause of my back yard being warm.
On the other hand, I don't think that the specific location of my back yard being warm for one short period of time has much to do with global warming due to increased atmospheric greenhouse gases resulting from human burning of fossil fuels over a period of decades.
Perhaps you would actually be willing to provide us with an argument as to why your anecdote is more relevant than mine?
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nealjking at 09:37 AM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
s_gordon_b:
You wrote:
"Two and 3, by definition, lacked the scope to indicate one way or another whether they support the consensus. Basically, just as most of all of the abstracts that were rated lacked the scope to comment at all on causation; 2 and 3 lacked the scope to comment on the consensus quantification of causation."
That is an interpretation you can assert, but from my involvement and discussion with the study evaluators, I know that they would not have checked off on levels of support 2 or 3 without having come to the conclusion that the abstract was assenting to a support for a significant (not minimal) degree of global warming, due to human influence. They bent over backwards to avoid reading too much support into a statement: Why do you think there are so many neutrals? If the evaluators had been willing to interpret perceived lukewarm support or a tiny perceived impact as 2 or 3, there wouldn't be many neutrals at all.
What you're proposing is a conceivable interpretation of the words in the paper, but bears no relationship to how the evaluators actually worked.
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Tom Curtis at 09:18 AM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
s_gordon_b @220, you claim that categories 2 and 3 do not support the consensus because:
"Two and 3, by definition, lacked the scope to indicate one way or another whether they support the consensus. Basically, just as most of all of the abstracts that were rated lacked the scope to comment at all on causation; 2 and 3 lacked the scope to comment on the consensus quantification of causation."
First, whether or not the abstracts lack sufficient information to categorize them is irrelevant to the meaning of "endorse AGW". Your argument, if valid, at most shows that categories (2) and (3) should be empty sets.
Seting that argument aside, several cues require us to give "endorse AGW" and "reject AGW" the same meanings where ever they occur in the list of categories. Of these the most important is that if you do not, if you allow "endorse AGW" to mean "endorse the claim that humans have caused most of recent warming" in (1), but "humans have caused at least some part of recent warming" in (2) and (3), then abstracts can logically belong to both categories (2) {or (3)} and category (7) at the same time. Given that the categories are clearly intended to be exclusive, it follows that if "endorse AGW" and "reject AGW" can be interpreted in a way that makes them exclusive it they should be; and that any interpretation that makes them non-exclusive is a misinterpretation. If follows that "endorse AGW" and "reject AGW" must be given the same meaning whereever they occur in the rating system, and that the difference in ratings for endorsements and rejections is a difference not in the level of endorsement (or rejection) but in the clarity of the endorsement or rejection in the abstract.
Several critics of the consensus have bizarrely criticized the paper both on the grounds that both the ratings at different level vary the meaning of "endorse AGW" and that the ratings are inconsistent due to overlap. They do not appear to recognize that by doing so they make their criticism inconsistent. Specifically, they make it clear that they show their criticism to be based on a hostile, out of context interpretation of the ratings and therefore irrelevant.
Leaving that aside, consider how you would rate the following title and abstract:
"On Regional Labor Productivity
Global climate change will increase outdoor and indoor heat loads, and may impair health and productivity for millions of working people. This study applies physiological evidence about effects of heat, climate guidelines for safe work environments, climate modelling and global distributions of working populations, to estimate the impact of two climate scenarios on future labour productivity. In most regions, climate change will decrease labour productivity, under the simple assumption of no specific adaptation. By the 2080s, the greatest absolute losses of population based labour work ability as compared with a situation of no heat impact (11-27%) are seen under the A2 scenario in South-East Asia, Andean and Central America, and the Caribbean. Climate change will significantly impact on labour productivity unless farmers, self-employed and employers invest in adaptive measures. Workers may need to work longer hours to achieve the same output and there will be economic costs of occupational health interventions against heat exposures."
How would you rate it?
It certainly does not ascribe a specific portion of recent warming to anthropogenic factors, so according to your argument it should be rated as neutral (4) at best. It was actually rated as implicitly endorsing AGW (3)*, a rating I agree with because:
1) It explicitly indicates, "Global climate change will increase outdoor and indoor heat loads" (my emphasis), something we have no reason to believe if anthropogenic factors are not the main driver of recent and near future temperature changes.
2) It implicitly endorses the IPCC A2 scenario as a plausible scenario of future temperature evolution; thereby implicitly endorsing the causal connection between greenhouse gases and temperature rise shown in that scenario including the forcing history and relationship to temperature in recent times. That forcing history, of course, shows anthropogenic factors as the cause of greater than 50% of recent warming.
I think the suposition that categories (2) and (3) cannot endorse anthropogenic factors as causing >50% of recent warming is simply wrongheaded, as shown by the example above. Of course any proposition that can be stated explicitly with quantification can also be stated explicitly without quantification by the use of such terms as "most of" (as in "most of recent warming is due to anthropogenic factors") or "dominant" (as in "the dominant cause of recent warming has been anthropegenic factors"). Further, anything that can be stated explicitly can be stated implicitly by leaving part of the affirmation to background information.
In the end, your objection comes down to the claim that it is easier to make mistakes about categories (2) and (3) than category (1). As the endorsement becomes less explicit and precise, it becomes easier to mistake endorsement for a neutral paper, and vise versa. That, at least, is true. Given the comparison between abstract rated and self rated papers, however, the mistakes have overwelmingly been conservative so the papers conclusions stand.
*One of the author's of the paper has rated it as neutral (4), but in ongoing comments he has shown that he does not understand the rating system by indicating that he thinks there is a "luke warm" category (which is clearly a mistake), and implicitly endorsed a claim by a well known "skeptic" that the consensus position is that "... almost 90-100% of the observed global warming was induced by human emission", which is absurd given the actual statements from the IPCC. It follows that the author (Richard Tol) is so confused about what is being endorsed and the rating system that his self ratings are irrelevant. I discuss his claims further on my blog.
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Tom Dayton at 09:10 AM on 28 May 2013Medieval Warm Period was warmer
William Haas, read the Intermediate tab of this posting, and take special note of the description of the "seminal paper on this subject." Click that phrase on that page to get to the details. It is irrelevant that as you wrote "for a specific location" temperatures were warmer than today. "Global" warming means more than one specific location, and there was no synchronized global Medieval Warm Period. So your vague contrarian speculation is irrelevant; you are speculating about a non-event.
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Rob Honeycutt at 08:51 AM on 28 May 2013Medieval Warm Period was warmer
William Haas... No one claims that man-made CO2 had any effect during Medieval times. There are, though, other known factors at play during that period, including increased solar activity and low volcanic activity. But, overall, it is estmated that current global temperature is likely as high or higher than the MWP. This in spite of the fact that the planet has been on a 5000 year orbitally forced trend toward generally cooler conditions.
Currently there is no other rational explanation for the temperature trend since modern industrialization other than increased levels of man-made greenhouse gases.
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William Haas at 08:37 AM on 28 May 2013Medieval Warm Period was warmer
Estimates of global temperatures during the Me devil Warm Period are somewhat speculative because we do not have direct measurements of global temperatures dating back that far. There is proxy data that shows that for a specific location, temperatures were warmer during the Medieval Warm Period then they are today and man's contribution of CO2 to the atmosphere could not have played a part.
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Tom Curtis at 07:44 AM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
s_gordon_b @221, try searching for the terms " " (ie, a single space) or "i" for a generalized search.
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s_gordon_b at 07:09 AM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
JasonB,
I wrote: "I still don't see how I can use that page to get those figures."
D'oh. I mistook the search page for the "rate abstracts" page. It does insist you enter a search term, though, which limits the results.
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s_gordon_b at 06:42 AM on 28 May 2013Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Hi JasonB,
You wrote in reply to my post:
Perhaps it would be easier to understand your point if you could point us to some examples of where the study is being spun?
Ironically, in light of the methodology of the paper, the spin (more neutrally, I should call it confusion or conflation) starts with my "rating" of where Cook et al.'s abstract stands on AGW (emphasis below is mine):
"We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011 matching the topics 'global climate change' or 'global warming'. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW..."AGW is immediately defined as "the scientific consensus on anthropogenic global warming," not in the broadbrushed, imprecise, popular way that ranges from "we're a significant contributor, along with natural causes" to "we're the cause." In the next breath, we're told that "32.6% endorsed" that consensus. Ask anyone who reads climate science papers what the term "scientific consensus on anthropogenic global warming" means in the context of such a paper, and how many will say "simple: humans are a significant cause of global warming" vs "it refers to the consensus of the IPCC and pretty much all of the other major scientific review bodies that humans are the dominant (if not the only) cause of global warming, at least since the 1950s"? In climate science circles "consensus" has a precise meaning. And this is a climate science paper. This is why when I initially read about the paper - and based on my very high level of trust in SkS - I took the claim about support for "the consensus" literally, in the IPCC sense, and represented the paper that way on social media. It's also why I was stunned when I actually read the paper and got to the part where categories 1, 2 and 3 were rolled up together and rated as "the consensus." Not so. Two and 3, by definition, lacked the scope to indicate one way or another whether they support the consensus. Basically, just as most of all of the abstracts that were rated lacked the scope to comment at all on causation; 2 and 3 lacked the scope to comment on the consensus quantification of causation.
You continued:
Regarding the authors, again, they were asked to state whether each specific paper endorsed the proposition that anthropogenic GHGs are causing global warming, rejected the proposition that anthropogenic GHGs are causing global warming, or was neutral. If the author of the paper felt that their paper implied humans were having a minimal impact on global warming (e.g. by proposing an alternative as the main cause of global warming), or stated that human impact was minimal or non-existent, or stated that humans were causing less then half of global warming, then they would have categorised their own papers as rejecting the proposition.
I'm fairly confident that anyone who rejected the consensus view would have made damn sure their paper was counted as a rejection if it was at all possible to do so! And let's not forget that the authors of any papers who feel their paper should have been counted as a rejection are free to search for their paper in the results and alert us to the miscategorisation.
You're misunderstanding my argument. I'm not in any way suggesting that minimizing or denying papers were lumped into the "endorsing"/consensus-supporting abstract count. For example, if I wrote a paper that (to quote from the choices the authors were given) "... explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a given fact," I would concur if it was rated as category 2. Likewise, I would concur with a category 3 rating if my "paper implies humans are causing global warming. E.g., research assumes greenhouse gases cause warming without explicitly stating humans are the cause." But I would concur in both these cases even if my paper had zero to say for or against the IPCC consensus on degree of causation. Indeed, if my paper had supported the consensus, I would have rated it 1.
Anyway, the bottom line is that the authors of 97.2% of the papers that took a position stated that their papers endorsed the proposition that anthropogenic greenhouse gasses are causing global warming. That's it.
Exactly. They "endorsed the proposition that anthropogenic greenhouse gasses are causing global warming." "Are causing" can be read the same way as "obesity is causing Type 2 diabetes": it's a contribuitng cause. But, again, only a fraction of the papers were designed to endorse or reject the dominant cause IPCC consensus implied in the abstract and in all manner of coverage that has followed. E.g.:
From the lead in Suzanne Goldberg's story in The Guardian (http://www.guardian.co.uk/environment/2013/may/16/climate-research-nearly-unanimous-humans-causes):"A survey of thousands of peer-reviewed papers in scientific journals has found 97.1% agreed that climate change is caused by human activity."
When I write (as a journalist) or read "is caused by" in the context of the climate change social debate (it is a debate, in civil society; otherwise there would be no need for this paper and the Consensus Project), my meaning/understanding is primary causation, if not "the cause."
There's no shortage of argument on this board about the semantics used in the study and surrounding it. Cook et al. could simply address this by releasing a clarification, unless they really believe it's scentifically sound to infer that category 2 and 3 papers do endorse the consensus. Alternately, they could go through all their past writings and redefine their use of the word consensus to mean that human activities are at least a significant contributor to global warming.
Quoting and answering me:
*I've looked everywhere, but I can't find where the numbers of abstracts assigned to each of the original Table 2 categories is or the category assignments by the study authors. Could you point me to that data?
http://www.skepticalscience.com/tcp.php?t=search
I had already gone there. I still don't see how I can use that page to get those figures. Why isn't the data simply published somewhere? It's such basic information for people who want to understand the study's findings.
Perhaps you should spend some time reading the earlier comments to avoid rehashing the same points over and over again.
I read plenty and found little beyond arguments about semantics. But now you've provided me numbers for category 1 in your earlier post, where you write:
... of interest to this discussion is the breakdown between papers that quantify the human contribution to global warming as >= 50% and papers that quantify the human contribution to global warming as < 50% (i.e. levels 1 and 7), since there is no interpretation required for those. The former represent 88% of all papers that quantify the human contribution to global warming (64 of 73).
I think you've made a fundamental error here. For a paper to unambiguously support the IPCC et al. consensus, it does indeed have to fall into category 1. But for a paper to unambiguously reject or deny it, it only has to fall into category 5, 6 or 7. That's 0.7 of 11,944 papers = 84 (maybe a few more, judging by the responses to some to the queries Popular Technology sent to known anti-AGW scientists whose papers had been rated). So the proper comparison, it seems to me, is 64 vs 84 or 64 out of 148 explicitly, unambiguously endorsing vs rejecting the IPCC consensus.
For me, the lesson of this study is that it's very hard to find robust support for the IPCC consensus just by doing a head count of papers on climate change, because very few papers, so far at least, have explicitly (or implictly, I suppose) sought to test that quantified consensus. Maybe this is analogous to the relationship between any large body of literature and the relatively uncommon major reviews and meta-analyses that attempt to put it all together and draw those larger conclusions of which consensuses are made.
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John Hartz at 06:21 AM on 28 May 2013A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
Also see:
Cassano, E. N., Cassano, J. J., Higgins, M. E. and Serreze, M. C. (2013), Atmospheric impacts of an Arctic sea ice minimum as seen in the Community Atmosphere Model. Int. J. Climatol.. doi: 10.1002/joc.3723
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Rob Painting at 06:08 AM on 28 May 2013Uncertainty no excuse for procrastinating on climate change
Kev, my bad. And I did read the paper! Mind you the first sentence in the paper is misleading.
It's not easy tracking down all the sources for their inputs into the calculations, but their choice of climate forcing seems to be the clincher. The use of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) forcing moves the equilibrium climate sensitivity back up to 2.4°C - closer to the central estimate using other methods.
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John Hartz at 05:32 AM on 28 May 2013Land Surface Warming Confirmed Independently Without Land Station Data
Dana,
Your "Note" at the end of the OP needs an edit.
Also, shouldn't the rebuttal article, It's Urban Heat Island effect also be updated in a similar manner?
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william5331 at 04:55 AM on 28 May 2013A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
R. Gates (18)
There is another phenomenon that is likely. When low pressure systems sidle up to the Atlantic side of Greenland, they induces katabatic winds down the flanks of Greenland. Presumably the same will happen if a low can get close to the northern coast. All that is necesary is for the ice to disappear. The ice shelf tends to hold low pressure areas off the coast and weaken them. Katabatic warming for descending air (no dew point involved as is the case with rising air) is 9.8 degrees per vertical km. From the very peak of Greenland to the coast is over 3km or about 300C. With a hurricane such as the one that we had Aug6, 2012, we should see some serious surface melting.
http://mtkass.blogspot.co.nz/2012/11/greenland-melting.html
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