Arguments
Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Posted on 16 May 2013 by dana1981, John Cook
A new survey of over 12,000 peer-reviewed climate science papers by our citizen science team at Skeptical Science has found a 97% consensus among papers taking a position on the cause of global warming in the peer-reviewed literature that humans are responsible.
Lead author John Cook created a short video abstract summarizing the study:
The Abstracts Survey
The first step of our approach involved expanding the original survey of the peer-reviewed scientific literature in Oreskes (2004). We performed a keyword search of peer-reviewed scientific journal publications (in the ISI Web of Science) for the terms 'global warming' and 'global climate change' between the years 1991 and 2011, which returned over 12,000 papers. John Cook created a web-based system that would randomly display a paper's abstract (summary). We agreed upon definitions of possible categories: explicit or implicit endorsement of human-caused global warming, no position, and implicit or explicit rejection (or minimization of the human influence).
Our approach was also similar to that taken by James Powell, as illustrated in the popular graphic below. Powell examined nearly 14,000 abstracts, searching for explicit rejections of human-caused global warming, finding only 24. We took this approach further, also looking at implicit rejections, no opinions, and implicit/explicit endorsements.
We took a conservative approach in our ratings. For example, a study which takes it for granted that global warming will continue for the foreseeable future could easily be put into the implicit endorsement category; there is no reason to expect global warming to continue indefinitely unless humans are causing it. However, unless an abstract included (either implicit or explicit) language about the cause of the warming, we categorized it as 'no position'.
Note that John Cook also initiated a spinoff from the project with a survey of climate blog participants re-rating a subset of these same abstracts. However, this spinoff is not a part of our research or conclusions.
The Team
A team of Skeptical Science volunteers proceeded to categorize the 12,000 abstracts – the most comprehensive survey of its kind to date. Each paper was rated independently at least twice, with the identity of the other co-rater not known. A dozen team members completed most of the 24,000+ ratings. There was no funding provided for this project; all the work was performed on a purely voluntary basis.
Once we finished the 24,000+ ratings, we went back and checked the abstracts where there were disagreements. If the disagreement about a given paper couldn't be settled by the two initial raters, a third person acted as the tie-breaker.
The volunteers were an internationally diverse group. Team members' home countries included Australia, USA, Canada, UK, New Zealand, Germany, Finland, and Italy.
The Self-Ratings
As an independent test of the measured consensus, we also emailed over 8,500 authors and asked them to rate their own papers using our same categories. The most appropriate expert to rate the level of endorsement of a published paper is the author of the paper, after all. We received responses from 1,200 scientists who rated a total of over 2,100 papers. Unlike our team's ratings that only considered the summary of each paper presented in the abstract, the scientists considered the entire paper in the self-ratings.
The 97% Consensus Results
Based on our abstract ratings, we found that just over 4,000 papers expressed a position on the cause of global warming, 97.1% of which endorsed human-caused global warming. In the self-ratings, nearly 1,400 papers were rated as taking a position, 97.2% of which endorsed human-caused global warming.
We found that about two-thirds of papers didn't express a position on the subject in the abstract, which confirms that we were conservative in our initial abstract ratings. This result isn't surprising for two reasons: 1) most journals have strict word limits for their abstracts, and 2) frankly, every scientist doing climate research knows humans are causing global warming. There's no longer a need to state something so obvious. For example, would you expect every geological paper to note in its abstract that the Earth is a spherical body that orbits the sun?
This result was also predicted by Oreskes (2007), which noted that scientists
"...generally focus their discussions on questions that are still disputed or unanswered rather than on matters about which everyone agrees"
However, according to the author self-ratings, nearly two-thirds of the papers in our survey do express a position on the subject somewhere in the paper.
We also found that the consensus has strengthened gradually over time. The slow rate reflects that there has been little room to grow, because the consensus on human-caused global warming has generally always been over 90% since 1991. Nevertheless, in both the abstract ratings and self-ratings, we found that the consensus has grown to about 98% as of 2011.
Percentage of papers endorsing the consensus among only papers that express a position endorsing or rejecting the consensus. From Cook et al. (2013).
Our results are also consistent with previous research finding a 97% consensus amongst climate experts on the human cause of global warming. Doran and Zimmerman (2009) surveyed Earth scientists, and found that of the 77 scientists responding to their survey who are actively publishing climate science research, 75 (97.4%) agreed that "human activity is a significant contributing factor in changing mean global temperatures." Anderegg et al. (2010) compiled a list of 908 researchers with at least 20 peer-reviewed climate publications. They found that:
"≈97% of self-identified actively publishing climate scientists agree with the tenets of ACC [anthropogenic climate change]"
In our survey, among scientists who expressed a position on AGW in their abstract, 98.4% endorsed the consensus. This is greater than 97% consensus of peer-reviewed papers because endorsement papers had more authors than rejection papers, on average. Thus there is a 97.1% consensus in the peer-reviewed literature, and a 98.4% consensus amongst scientists researching climate change.
Why is this Important?
Several studies have shown that people who correctly perceive the scientific consensus on human-caused global warming are more likely to support government action to curb greenhouse gas emissions. This was most recently shown in McCright et al. (2013), recently published in the journal Climatic Change. People will defer to the judgment of experts, and they trust climate scientists on the subject of global warming.
However, research has also shown that the public is misinformed on the climate consensus. For example, a 2012 poll from US Pew Research Center found less than half of Americans thought that scientists agreed that humans were causing global warming. One contributor to this misperception is false balance in the media, particularly in the US, where most climate stories are "balanced" with a "skeptic" perspective. However, this results in making the 3% seem much larger, like 50%. In trying to achieve "balance", the media has actually created a very unbalanced perception of reality. As a result, people believe scientists are still split about what's causing global warming, and therefore there is not nearly enough public support or motivation to solve the problem.
Such false balance has long been the goal of a dedicated misinformation campaign waged by the fossil fuel industry. Just as one example, in 1991 Western Fuels Association conducted a $510,000 campaign whose primary goal was to "reposition global warming as theory (not fact)." These vested interests have exploited the media desire to appear "balanced."
Open Access for Maximum Transparency
We chose to submit our paper to Environmental Research Letters because it is a well-respected, high-impact journal, but also because it offers the option of making a paper available by open access, meaning that for an up-front fee, the paper can be made free for anybody to download. This was important to us, because we want our results to be as accessible and transparent as possible.
To pay the open access fee, in keeping with the citizen science approach, we asked for donations from Skeptical Science readers. We received over 50 donations in less than 10 hours to fully crowd-fund the $1,600 open access cost.
Human-Caused Global Warming
We fully anticipate that some climate contrarians will respond by saying "we don't dispute that humans cause some global warming." First of all, there are a lot of people who do dispute that there is a consensus that humans cause any global warming. Our paper shows that their position is not supported in the scientific literature.
Second, we did look for papers that quantify the human contribution to global warming, and most are not that specific. However, as noted above, if a paper minimized the human contribution, we classified that as a rejection. For example, if a paper were to say "the sun caused most of the global warming over the past century," that would be included in the less than 3% of papers in the rejection categories.
Many studies simply defer to the expert summary of climate science research put together by the Intergovernmental Panel on Climate Change (IPCC), which states that most of the global warming since the mid-20th century has been caused by humans. According to recent research, that statement is actually too conservative.
Of the papers that specifically examine the human and natural causes of global warming, virtually all conclude that humans are the dominant cause over the past 50 to 100 years.
Net human and natural percent contributions to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, light green), Lean and Rind 2008 (LR08, purple), Huber and Knutti 2011 (HK11, light blue), Gillett et al. 2012 (G12, orange), Wigley and Santer 2012 (WS12, dark green), and Jones et al. 2013 (J13, pink).
Most studies simply accept this fact and go on to examine the consequences of this human-caused global warming and associated climate change.
Another important point is that once you accept that humans are causing global warming, you must also accept that global warming is still happening; humans cause global warming by increasing the greenhouse effect, and our greenhouse gas emissions just keep accelerating. This ties in to our previous posts noting that global warming is accelerating; but that over the past decade, most of that warming has gone into the oceans (including the oft-neglected deep oceans). If you accept that humans are causing global warming, as over 97% of peer-reviewed scientific papers do, then this conclusion should not be at all controversial. With all this evidence for human-caused global warming, it couldn't simply have just stopped, so the heat must be going somewhere. Scientists have found it in the oceans.
Spread the Word
Awareness of the scientific consensus on human-caused global warming is a key factor in peoples' decisions whether or not to support action to reduce greenhouse gas emissions. However, there is a gap here due to the public's lack of awareness of the consensus. Thus it's critical that we make people aware of these results. To that end, design and advertising firm SJI Associates generously created a website pro-bono, centered around the results of our survey. The website can be viewed at TheConsensusProject.com, and it includes a page where relevant and useful graphics like the one at the top of this post can be shared. You can also follow The Consensus Project on Twitter @ConsensusProj, and on Facebook.
Quite possibly the most important thing to communicate about climate change is that there is a 97% consensus amongst the scientific experts and scientific research that humans are causing global warming. Let's spread the word and close the consensus gap.
Coming tomorrow, details about a feature that will let you test our results by rating the papers directly yourself. The Consensus Project results have also been incorporated into the rebuttals to the myths There is no consensus and IPCC is alarmist.
Vonnegut, you should use the interactive widget that shows the evolution of the numbers of papers across the many decades. It illustrates the point that CBDunkerson made to you. It is the Interactive History of Climate Science widget that is linked from the graphic in the left margin of every Skeptical Science page.
Vonnegut... Out of 8500 emails sent out we received responses from 1500 scientists.
For an email blast, 15% is a very high response rate! Remember, researchers tend to be under paid and over worked. Lots of them are going to be out doing field research at any given time (when you're working in Antarctica on an ice core, you're not spending a lot of time going through emails). Lots of the emails are going to have just been bad addresses. Lots probably went straight into spam filters.
Most mass email blasts would expect less than 1% response rate. Anything over 1% would be considered highly successful. The fact that we got a 15% participation rate suggests to me, exactly what you're saying, that scientists believe this is a very important issue.
I read the details of your study more closely for the first time after it was challenged by Popular Technology:
http://www.populartechnology.net/2013/05/97-study-falsely-classifies-scientists.html
I can't tell the truth behind the claims of Popular Technology. From what I can tell, a handful of papers might have been incorrectly classified, though it also seems possible that these papers were classified correcty after all.
Can anyone shed light on the number of papers improperly classified? An update to this posting addressing this issue would really help.
paulhtremblay @305, the information you are after is given in summary form on table 5 of the paper:
Position Abstract rating Self-rating
Endorse AGW 791 (36.9%) 1342 (62.7%)
No AGW position or undecided 1339 (62.5%) 761 (35.5%)
Reject AGW 12 (0.6%) 39 (1.8%)
As you can see, the abstract ratings sigificantly underestimated endorsements relative to the author self ratings. They also underestimated rejections, but massively over estimated "no position" papers. That is unsurprising in that the abstract ratings were done on the basis of the abstract and title alone, with no information about authors, time or journal of publication, nor the detailed contents of the papers. The authors, on the other hand had all of that information, plus information about their own intentions.
It is interesting to note that at least one of the authors who had papers "misrated" by abstract rating also responded to the author rating. Despite that, he emphasizes is unusual case ahead of the overall author rating statistics. Indeed, poptech also neglects the overall statistics, prefering cherry picked anecdotes to statistics from a large sample of respondents. Further, some of those cherry picked examples can easilly be shown to be incorrectly rating their papers.
Russ R. - Given that the question asked by Cook et al was really "what percentage of the literature agrees with the consensus", and that implicitly (Cat. 3) or explicitly (Cat. 2) were using the consensus position as a background fact of the abstracts and papers, your post is utter nonsense.
KR,
happy to discuss in the appropriate thread... reposting what I wrote before:
According to the data, only 1.6% of abstracts said that "humans are the primary cause of recent global warming".
Consensus at the 97% level did not include quantification, so it's factually misleading to say that the 97% position is that humans caused "most" of the warming.
Citing this paper you can say that:
Which will it be?
RussR, I think you are missing an important point about academic publishing in general and climatology in particular. Journal papers tend not to make specific claims in the abstract of a paper unless the contents of the paper specifically addresses that particular question. However, quite often the abstract will indirectly refer to some piece of commonly accepted knowledge in providing background or motivation for the question actually addressed in the paper.
In climatology, there is a type of paper known as an "attribution study" which seek to discover what factors explain climate in some region or period of time. It is only in these papers where you should expect the abstract to contain an explicit statement on the cause of the warming. However, most climate papers are not attribution studies, and discuss some other aspect of climate change. For instance I contributed to a paper on statistical downscaling (which relates large scale atmospheric circulation to small scale local climate). The methods for this are the same whether the climage change is anthropogenic or natural or a bit of both, so there is no good reason for it to have anything more than implicit acceptance (in explaining the reasons why downscaling is likely to be a useful thing to do).
The measure used by TCP is perfectly reasonable, if you understand the nature of scientific publication, and are aware that attribution studies are only a small fraction of the papers publiched on climate change.
Russ R:
I would say you're playing at rhetorical silly buggers, and your attempt to limit the response space to your carefully-worded set is insultingly obvious.
Basically, your line of reasoning only makes sense if you ignore studies of paleo- and historical (read: Holocene) climate and simultaneously ignore the physics of greenhouse gases.
Consider how Cook et al defines category 3 (implicit endorsement):
Given historical climate and physics, the only way that implicit endorsement means "implicitly endors[ing] that humans are a cause of warming" where "a" is something less than primary (that is, over half) is if there is some as-yet undiscovered sink absorbing human CO2 emissions and, simultaneously, an as-yet undiscovered source of CO2 that is releasing it into the atmosphere - and moreover, the CO2 from this mysterious source just happens to possess a carbon isotope signature that matches fossil fuel CO2 as a total coincidence.
I'm pretty sure we're getting into extraordinary claims requiring extraordinary evidence territory here, so I think you need to pony up some research hinting at these as-yet undiscovered sources and sinks if you wish to persist with this line of argument.
Russ R. - Then perhaps you should actually read the Cook et al paper, paying some attention to the exclusive (i.e., pick only one) and ordered endorsement categories in that methodology. Categories applied to how AGW was referenced, how the literature (and authors) regard AGW, not just to what are explicitly attribution studies.
If your abstract/paper implied, expressed, or explicitly stated that people have minimal impact on climate change, i.e. "a natural mechanism is the main cause of global warming", your abstract/paper would be rated as 5, 6, or 7 respectively.
If your abstract/paper implied, expressed, or explicitly stated that "humans are causing global warming" - note, not "contributing" but "causing", i.e. the primary or dominant cause as per any reasonable use of English, the abstract/paper would be rated as 3, 2, or 1 respectively.
From the methodology, the instructions to the authors for self-ratings: "Note: we are not asking about your personal opinion but whether each specific paper endorses or rejects (whether explicitly or implicitly) that humans cause global warming":
The claim that only category 1 ratings count is utter nonsense, raised only by ignoring the categories as a whole, taking the AGW endorsement ratings out of context from the AGW rejection categories. And by what I consider deliberate misreading of "are causing" as the semantically distinct "are a cause".
I will note that this issue has been discussed at some length - I suggest you read through some of this thread. As per the categories which describe whether an abstract/paper endorses/rejects AGW, 3896 endorsed and only 78 rejected it.
---
What I find most fascinating is that the rated abstracts are made readily available - it would be almost trivial to define your own categorization criteria, as specific as you want, and review a hundred or so abstracts in an afternoon to see if those criteria gave different results. Nobody criticizing Cook et al has stepped up to this.
I suspect (personal opinion) that's because everyone realizes that the only way to get a significantly different percentage from rating the literature is to do it wrong, with patently absurd criteria. And that barring any support for 'skeptic' positions from the data, the only avenue they have left is to nitpick, misinterpret, and distort in an attempt to discredit (not disprove) the conclusions.
Don't worry KR, the paper's methods do more than enough to discredit it, but that's a different matter, which I can get into later. (Or you can read for yourself here, here, and here.)
Assuming for the moment that the methodology was valid, I'm only objecting to a misrepresentation of its findings, specifically the word "most" in "humans caused most of the warming." (I have absolutely no objection to the claim that "97% of papers stated (implicitly or explicitly) that humans are causing warming")
The word "most" can only apply to Level 1 endorsement that actually contain some measure of attribution. It does not appear in Level 2 or 3 endorsement. To claim that these abstracts support a consensus of "most warming being caused by humans" is outright false. They say no such thing:
For the record, if asked, I'd self-rate my own personal opinion as Level 2 "endorsement without quantification". So, this isn't part of a denier agenda.
I just expect this website to accurately report the paper's actual findings... not make up whatever suits your cause.
But do what you like... it's your credibility that you're risking.
[JH] Please note that the OP is written by John Cook and Dana Nuccitelli. Cook is the lead author of Quantifying the consensus on anthropogenic global warming in the scientific literature, Cook et al, 2013, Environmental Research Letters. Nuccitelli is a co-author of the ERL paper. Are you stating that Cook and Nuccitelli deliberately misrepresented the findings of the ERL paper in the OP?
Russ R: Please note that the SkS Comments Policy includes the following prohibition:
Don't worry KR, the paper's methods do more than enough to discredit it, but that's a different matter, which I can get into later. (Or you can read for yourself here, here, and here.)
(snip)
Assuming for the moment that the methodology was valid, I'm only objecting to a misrepresentation of its findings, specifically the word "most" in "humans caused most of the warming." (I have absolutely no objection to the claim that "97% of papers stated (implicitly or explicitly) that humans are causing warming")
The word "most" can only apply to Level 1 endorsement that actually contain some measure of attribution. It does not appear in Level 2 or 3 endorsement. To claim that these abstracts support a consensus of "most warming being caused by humans" is outright false. They say no such thing:
For the record, if asked, I'd self-rate my own personal opinion as Level 2 "endorsement without quantification". So, this isn't part of a denier agenda.
(snip)
I just expect this website to accurately report the paper's actual findings... not make up whatever suits your cause.
But do what you like... it's your credibility that you're risking.
[RH] You'll have to conduct this discussion without the aid of linking to outside sources accusing fraud.
Russ R. - Once again, you are ignoring details such as Category 4, "a natural mechanism is the main cause of global warming" - excluding humans as a minor cause from 1, 2, and 3
Not to mention the instructions for applying categories:
The second drop down indicates the level of endorsement for the proposition that human activity (i.e., anthropogenic greenhouse gases) is causing global warming (e.g., the increase in temperature).
Not "a cause", but "causing", as in the main actor. Instead, you play rhetorical games, reject common English usage, and ignore the context within which the categories were defined.
You reference several blog posts by J. Duarte - who seems to feel that the Cook et al authors were dishonest idiots (the paper passed peer review of methods and results by reviewers the editors respected for domain knowledge), that the raters were blinded by ideological bias (totally ignoring the author ratings giving confirming identical results), complaining about raters discussing criteria (when it's essential for everyone to agree on the same critera, clarifying ambiguities - and that radom presentation prevented collusion on any particular item), and in general making truly absurd and unsupported accusations.
Your uncritical presentation of his blog rants as support is, IMO, the clearest evidence that you are far more interested in attacking conclusions that ideologically offend you, than actually concerned about the methods that highlight those conclusions - playing the man and not the ball, a type of ad hominem fallacy.
Sorry, was trying to respond to the moderators comments @312, but for some reason my last comment was repeated.
I'll try again... shorter this time:
No, I'm not refering to the OP (i.e. "Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature" Posted on 16 May 2013 by dana1981, John Cook).
I'm specifically refering to another post (and subsequent comments), The 97% v the 3% – just how much global warming are humans causing? Posted on 15 September 2014 by dana1981.
Dana writes:
"96–97% of climate experts in arguing that humans have been the dominant cause of global warming since 1950"
and
"96–97% of climate science experts and peer-reviewed research agree that humans are the main cause of global warming."
These claims are not supported by Cook et al (2013), since only 1.6% of the reviewed papers stated "that humans are causing most of global warming".
Whether the overstatement is deliberate or not, I don't care to speculate. But it is a misrepresentation regardless.
KR:
Let's look at some of his claims then, shall we?
First: "The Cook et al. (2013) 97% paper included a bunch of psychology studies, marketing papers, and surveys of the general public as scientific endorsement of anthropogenic climate change."
Cook and Nucitelli claim their team reviewed "over 12,000 peer-reviewed climate science papers" and that papers which were "not climate-related" were excluded from the analysis.
Yet "in ten minutes with their database" Duarte found 19 papers that were included as endorsing the consensus, which were clearly not "climate science" papers.
His list begins in the fourth paragraph here.
The first two examples:
or
Would you argue that any of these should be considered "climate science" papers?
(snip)
[RH] You're going to have to find a way to do this without Duarte as his entire premise violates SkS policy:
It's been suggested many times over that Duarte, if he feels the results of Cook et al are not correct, he should endeavor to produce his own research into the issue.
Russ R is now running the misinterpretation of the classifications scam vs Cook et al 2013 (ie, claiming that the criteria for endorsement in Cook et al is only that some warming since 1950 be anthropogenic). I say it is a (rhetorical) scam because it was not the first or intuitive response of AGW "skeptics" to that paper. The first response was that authored by Poptech, in which Nicolas Scaffeta wrote:
You will notice that correctly identifies the Cook et al criteria for endorsement, ie, that it indicates that 50% plus of recent warming was anthropogenic, and tries to call it a strawman because it does not match his blatant misrepresentation of the IPCC position.
Indeed, if a paper that endorses only that some recent warming is anthropogenic belongs to the Cook et al 97%, then both Sceffeta's and Shaviv's papers (discussed by Poptech) should have been classified as endorsing the consensus. Likewise, if a paper that endorses only that some recent warming is anthropogenic belongs to the Cook et al 97%, then all four of Richard Tol's papers which he claims to not have endorsed the consensus, should have been classified as endorsing the concensus.
A number of major AGW "skeptics" and Richard Tol have endorsed these claims of misclassification, including Watts (who reposted the claims), Tol who reposts it and a number who have commented either at WUWT or on Tol's tweet without demuring that Shaviv's description of the Cook et al classification was wrong. In fact, I have been unable to find one objection to Scaffeta's claims, or the claims that these papers were misrated based on the supposed fact that the Cook et al 97% endorsed only some anthropogenic warming rather than 50% +.
That, of course, merely demonstrates that the AGW "skeptics" are inconsistent in their criticism of Cook et al. It does not demonstrate that Scaffeta (and Tol's) 50%+ interpretation is correct. So, let us examine the possibility that "level of endorsement of AGW" in Cook et al means just endorsement of the claim that at least some of recent warming has been anthropogenic (ie, that anthropogenic factors have not had either no effect, or tended to cool recent temperatures).
So, consider the classification scheme used in Cook et al:
For this categorization to be consistent it must satisfy two criteria:
1) No paper must fall under more than one classification;
and
2) If different levels of concensus represent different minimum percentages of anthropogenic contribution, they must change monotonically with classification level.
Now clearly if "endorse AGW" means "endorse that "at least some of recent warming has been anthropogenic", then the categorization fails criteria (1). That is because any paper endorsing >0% but <50% anthropogenic warming must be categorized either 2 or 3, but also 7. Further, it also fails condition (2) for category 1 clearly applies only to papers which endorse 50% or more anthropogenic contribution to recent warming, while category 7 applies only to papers that endorse less than 50% anthropogenic contribution. The only monotonic ordering of endorsement levels possible, therefore, is on in which for all categories endorsement of AGW means endorsing 50% or more of recent warming as anthropogenic, and disendorsing means endorsing less than 50%.
If there are two ways to interpret a paper, one of which is consistent, and one of which is inconsistent, then clearly we must give preference to the consistent interpretation. Doing otherwise merely raises a strawman. Therefore, there is no rational way to interpret endorsement in Cook et al as anything other than "endorsement that 50% or more of recent warming was anthropogenic".
Ironically, despite this several AGW "skeptics" have criticized Cook et al both for using a definition of endorsement that allowed even hardcore deniers to belong to the 97% and also for being inconsistent. They prove thereby that there intent is only to criticize, not to actually rationally critique the paper.
Tom Curtis - I wholly agree with your comment. As I've stated several times, the 'skeptics' making this argument simply ignore the context of the range of exclusive classifications, not to mention the instructions provided to the raters and to the self-rating authors. And then they compound the nonsense by relating explicit attribution statements to all papers, rather than just the explicit attributions they highlight endorsing (65) versus those explicitly rejecting AGW (10).
Utter nonsense, disingenous misinterpretations of the paper.
It's truly remakable that a critique of a paper's methodology violates your site's comment policies.
(snip)
I'll ask again, specifically about the paper's method, making no allegation of intent or motives:
Did Cook et al. (2013) include psychology studies, marketing papers, and surveys of the general public, as scientific endorsement of anthropogenic climate change?
[RH] Moderation complaint snipped.
Note: Category (4) Not climate-related,
I'll take Moderator RH's response above as an implicit "No."
To clarify: "Category (4) Not climate-related" is described as papers relating to "Social science, education, research about people's views on climate".
That said, please see the following paper:
Semenza, J. C., Ploubidis, G. B., & George, L. A. (2011). Climate change and climate variability: personal motivation for adaptation and mitigation. Environmental Health, 10(1), 46.
The abstract describes the paper's methodology as follows: "In 2008, we conducted a cross-sectional survey in the United States using random digit dialing... Of 771 individuals surveyed, 81% (n = 622) acknowledged that climate change was occurring..."
This is a survey of the general public, and pretty obviously constitutues "research about people's views on climate" which should have been counted as "not climate-related" and excluded according to the paper's stated criteria.
And yet, the paper was included as "Mitigation" and counted as "Endorsement Level: 3". See here.
How exactly does this qualify as a "peer-reviewed climate science paper"?
I'll ask one more time (despite already knowing the answer)...
Did Cook et al. (2013) include psychology studies, marketing papers, and surveys of the general public, as scientific endorsement of anthropogenic climate change?
(snip)
[RH] Snipped for sloganeering.
Edit: Again, if you or anyone else believes the results of Cook13 are not robust, you're highly encouraged to perform your own research.
Russ R keeps on trying to push Duarte's list of abstracts he claims should not have been included in the results. For much of the list, Duarte's argument is weak, apparently presuposing that only articles dealing with attribution (and possibly climate sensitivity) are relevant. That represents a category error. Cook et al looked at the extent of endorsement of AGW in the scientific literature. A paper endorses a view if it states it, but also if it accepts it as the basis for further study. Duarte (and many AGW "skeptics") treat Cook et al as a survey of papers which provide evidence for attribution of 50% (or greater than 0% based on their misrepresentation) of recent warming to anthropogenic factors. Endorsing, and providing evidence for, are two very distinct things. The apparent inability of many supposedly intelligent AGW "skeptics" calls into question their knowledge of basic english. Cook et al, of course, was about endorsement as a proxy for acceptance of the theory by scientists. It had no need to survey evidence for the theories in that we have a set of comprehensive surveys of that evidence already, the most recent having been released by the IPCC last year.
Still, there are a few papers where the endorsement may be considered tenuous as an indication of the opinions of physical scientists. For the sake of argument, let us supose that they should not have been included in the survey. What difference would removing them make?
I have listed below key words that can be found in the titles of all articles identified by Duarte that might come under that category. After each key word, I have indicated the number of titles in his list in which the word appears, and the number of titles and/or abstracts in the Cook et al database in which they appear. (I have added Duarte's list at the end of this post, with relevant search words or word stems highighted. Titles with no words highlighted are in my opinion appropriately included, or have no convenient keyword that will not pick up a vast majority of obviously relevant abstracts.)
In all, 10 out of 19 of Duarte's list are covered by my search words, and another 2 were rated 4, and hence did not contribute to the consensus percentage in any event.
I then recalculated the consensu result on the assumption that all abstracts found by the searches using the key words should have been excluded. That is an absurd overestimate of the number that should have been excluded even if we grant Duarte's case because many of those found in the searches were categorized in categories that were not counted, rated at 4 and hence not counted, or clearly are appropriate for inclusion.
Despite bending over backwards to exclude papers based on Duarte's criticisms, the end result is that it adjusts the consensus rate down from 97.1% to 96.8%. That is right, even grossly inflating the figures for papers that should be excluded on Duarte's criteria only reduces the consensus rate by 0.3%
Duarte (and Russ R), of course, never make that calculation. Nor do they do a mini survey to estimate the rate of papers that should be excluded in their opinion. They do not do so because they have seen enough to know that the effect will be miniscule. Therefore they trump up a few cherry picked examples and hope the question of proportions never arises, all the better to decieve their readers.
The failure to determine ratios, and the failure calculated estimated effects of their "corrections" shows their criticism to not be science but pseudo-science.
I understand the moderator to have excluded several attempts by Russ R to introduce discussion of this material in comments, and will understant if the moderator considers even my discussion of topic and deletes it. However, it is trivially easy to show how pathetic is Duarte's criticism of Cook et al, and it seems a shame to me not to show that. Shoudl Russ R attempt to use this post a a springboard for more pseudo-science, I recommend that he only be permitted to discuss this list if in fact he determines ratios (making clear how he does so), and from that calculates the effects of his "corrections" on the headline result of the paper.
***********************************************************************
Opinion: 3, 50
Television: 1, 4
Perception: 2, 74
Promoting: 1, 97
Informing: 1, 6
Motiv: 1, 117
School: 1, 33
Total: 10, 381
(3896-381)/(4014-381) 96.8%
Chowdhury, M. S. H., Koike, M., Akther, S., & Miah, D. (2011). Biomass fuel use, burning technique and reasons for the denial of improved cooking stoves by Forest User Groups of Rema-Kalenga Wildlife Sanctuary, Bangladesh. International Journal of Sustainable Development & World Ecology, 18(1), 88–97.
Mitigation, 4
Boykoff, M. T. (2008). Lost in translation? United States television news coverage of anthropogenic climate change, 1995–2004. Climatic Change, 86(1-2), 1–11.
Mitigation, 2
De Best-Waldhober, M., Daamen, D., & Faaij, A. (2009). Informed and uninformed public opinions on CO2 capture and storage technologies in the Netherlands. International Journal of Greenhouse Gas Control, 3(3), 322–332.
Mitigation, 3
Tokushige, K., Akimoto, K., & Tomoda, T. (2007). Public perceptions on the acceptance of geological storage of carbon dioxide and information influencing the acceptance. International Journal of Greenhouse Gas Control, 1(1), 101–112.
Mitigation, 3
Egmond, C., Jonkers, R., & Kok, G. (2006). A strategy and protocol to increase diffusion of energy related innovations into the mainstream of housing associations. Energy Policy, 34(18), 4042–4049.
Impacts, 3
Gruber, E., & Brand, M. (1991). Promoting energy conservation in small and medium-sized companies. Energy Policy, 19(3), 279–287.
Mitigation, 3
Şentürk, İ., Erdem, C., Şimşek, T., & Kılınç, N. (2011). Determinants of vehicle fuel-type preference in developing countries: a case of Turkey.
Mitigation, 2
Grasso, V., Baronti, S., Guarnieri, F., Magno, R., Vaccari, F. P., & Zabini, F. (2011). Climate is changing, can we? A scientific exhibition in schools to understand climate change and raise awareness on sustainability good practices. International Journal of Global Warming, 3(1), 129–141.
Methods, 3
Palmgren, C. R., Morgan, M. G., Bruine de Bruin, W., & Keith, D. W. (2004). Initial public perceptions of deep geological and oceanic disposal of carbon dioxide. Environmental Science & Technology, 38(24), 6441–6450.
Mitigation, 3
Semenza, J. C., Ploubidis, G. B., & George, L. A. (2011). Climate change and climate variability: personal motivation for adaptation and mitigation. Environmental Health, 10(1), 46.
Mitigation, 3
Héguy, L., Garneau, M., Goldberg, M. S., Raphoz, M., Guay, F., & Valois, M.-F. (2008). Associations between grass and weed pollen and emergency department visits for asthma among children in Montreal. Environmental Research, 106(2), 203–211.
Impacts, 3
Lewis, S. (1994). An opinion on the global impact of meat consumption. The American Journal of Clinical Nutrition, 59(5), 1099S–1102S.
Mitigation, 3
De Boer, I. J. (2003). Environmental impact assessment of conventional and organic milk production. Livestock Production Science, 80(1), 69–77
Mitigation, 3
Acker, R. H., & Kammen, D. M. (1996). The quiet (energy) revolution: analysing the dissemination of photovoltaic power systems in Kenya. Energy Policy, 24(1), 81–111.
Mitigation, 3
Vandenplas, P. E. (1998). Reflections on the past and future of fusion and plasma physics research. Plasma Physics and Controlled Fusion, 40(8A), A77.
Mitigation, 4
Gökçek, M., Erdem, H. H., & Bayülken, A. (2007). A techno-economical evaluation for installation of suitable wind energy plants in Western Marmara, Turkey. Energy, Exploration & Exploitation, 25(6), 407–427.
Mitigation, 2
Gampe, F. (2004). Space technologies for the building sector. Esa Bulletin, 118, 40–46.
Mitigation, 3
Ha-Duong, M. (2008). Hierarchical fusion of expert opinions in the Transferable Belief Model, application to climate sensitivity. International Journal of Approximate Reasoning, 49(3), 555–574.
Methods, 3
Douglas, J. (1995). Global climate research: Informing the decision process. EPRI Journal.
Mitigation, 3
[RH] One can also assume that the reverse is true, that there are papers that were included in the "no position" category that should have been included with an endorsement level, thus rendering Duarte's objections null and void. He's arguing statistical noise.
Once again, if they doubt Cook et al results are robust, Duarte, Tol, Russ and others are enthusiastically invited to perform their own ratings analysis and submit to peer review.
I believe this horse (as aptly noted before) has been flogged... to... death. Let's please lay it to rest lest it stink up the place any further.
Of those papers that do quantify (73), 9 (12%) find less than 50%, and 64 (87%) find greater than 50%. I feel the authors of the study are being exceedingly generous in including most, if not all, of those nine. Four are from the same group of authors. The method and/or physics has been soundly debunked on most if not all (S&W 2011 isn't even a proper attribution study--just a curve-fitting exercise. Actually, I'm not aware of any comprehensive attribution study performed by anyone associated with the position that AGW accounts for less than half of the observed warming.). If we look at attribution studies that have not had serious claims against their methods, the number is not going to end up at 97%. It's going to end up at 100%.
Russ, if you were shown sound evidence strongly suggesting that the work of the Chilingar group was based on fundamental errors of physics and/or method, would you be critical of Cook et al. for including that work?
Elsewhere, jwalsh quotes Stranger, who says:
To which jwalsh responds:
In fact, AFAIK no AGW "skeptic" has replicated the study (or even a portion of the study) and posted the results on the internet. jwalsh can prove me wrong by posting a link. Even Tol's well known, and failed critique, which is often misdescribed as a replication only replicated the document search, and did not replicate either the abstract ratings nor the author ratings, and hence is not a replication of Cook et al 2013.
More importantly, jwalsh's response is a simple evasion of Stranger's question. "Replications" that pass muster in the denier blogosphere but stand no chance of passing peer review (typically because they are just short lists of cherry picked examples) are irrelevant. They just underline yet again that while deniers are very good at carping, they rarely bother to do science, still less quality science.
Two posts further on, jwalsh responds to me, writing:
While a refeshing admission of his own incompetence, this point totally ignores that Cook et al was a test of the accuracy of that method by comparison of the results with author self ratings, and that the author self-ratings also showed a 97% consensus. It is getting so you can tell the troll criticisms of Cook et al by their apparent complete lack of awareness of the author self ratings.
Critics of the Consensus Project seem to have two rather contradictory arguments:
Of course, the author self-ratings proved that the first objection is invalid. Some 28 scientists said that their papers rejected the consensus. That's 2.4% of all the authors who responded and 3.6% of the responders whose papers expressed an opinion on the AGW consensus.
As for the second one, it would be easy to show that the 97% estimate is too high, simply by finding consensus rejection abstracts that we missed. You don't have to slog through 12,000 abstracts (twice) like we did, just make a list (hint, ask Poptech) of the most prolific contrarians and search for their papers. Richard Tol performed some statistical alchemy that predicted that 300 such papers should exist, so there is surely some basis for expecting success here, unless of course you think that Tol's analysis is bunk.
Tom Curtis,
Thank you for your long reponse @322 to my question @320. A simple "yes" would have been sufficient.
(BTW, as I've mentioned before, my personal position would be Level 2, "Explicit endorsement without quantification". I've never disputed the paper's results, so telling me that these issues don't change the result does nothing to address the issues. I don't care if elimating the non-climate papers makes it a 99.8% consensus. That's not my point. The paper's methods and findings are my point, and that's specifically what I'm addressing.)
Now that we've establised that non-climate papers were indeed counted toward the consensus (contrary to the authors claims that these papers were excluded), let's address the claim that 97.1% of the papers which take a position endorse that "most" or ">50%" of warming is manmade, or that human activity is the "main cause", "primary cause" or "dominant cause" of warming.
Do all 3,896 abstracts that counted toward the 97.1% "Consensus" endorse anthropogenic warming as "most", ">50%", "main cause", "primary cause", "dominant cause' (or some similar majority concept), as opposed to merely stating that CO2 or human activity causes global warming? Again, a simple "Yes" or "No" will suffice.
As a tangible example, perhaps someone could explain how this paper which was included as "Mitigation" and rated Level 3 ("Implicit endorsement"), makes a case for the majority of warming being anthropogenic?
And while you're looking at it, could you also explain how it is "climate related"?
(snip)
[RH] Snipped for excessive (to the extreme) repetition. This issue has been fully and completely explored and you have been more than conclusively shown that the issues you're bring up are not sufficient to challenge the paper.
For the 100th time now, if you or Duarte or anyone else believes the results of Cook13 are not robust, then you should take the time to do what researcher do: Produce your own research testing the scientific consensus on climate change. We would all be excited to see your results. The track you are on now suggests that you are only interested in obfuscating the truth rather than revealing it.
Edit:
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DSL
I've never heard of the "Chilingar group", but if the papers:
Then yes, they should be rated and counted (along with whatever rebuttals have been published).
That was the study's stated methodology, wasn't it? I don't recall there being any test for fundamental errors in the papers prior to rating them.
Russ, AFAIK the stated methodology does not require the papers concerned to be on climatology, so if you question the potential inclusion of papers in phsychology, why not also question the inclusion of papers that are known to be incorrect. You can't have it both ways, the inclusion criterion were objective, which is important for replicability. If it includes a small number of studies of tangential relevance that seems a small price to pay, in my view.
If you want to perform a study that you feel in hindsight to be more informative, then go for it, replication is what science is all about. Quibbling over small details, without looking to see whether they affect the conclusions, is rather less productive.
Perhaps the final answer on whether Level 2 ratings endorse >50%:
It would appear that x = 97.1 and y = 1.6
(snip)
[RH] Reposting from material hacked from the SkS forum is way over the line.
Final warning.
DM beat me to it.
Russ, you're evading the question. Here it is again, in a different way: if we want to improve Cook et al., should we get rid of questionable papers (e.g. papers that are a stretch for the criteria, papers that are fundamentally flawed, papers that were "reviewed" by non-experts, etc.)? This doesn't add subjectivity into the calculation; it reduces it.
I'm surprised you don't know who Chilingar is. You found (or copied from Duarte) something to quibble with in the marginal papers that supported the consensus, yet you didn't spend the time to investigate the 3%. You simply trusted the method of Cook et al. where those were concerned.
RussR, there was no justification whatsoever for posting the text of a private discussion, you could have made your point perfectly well in your own words. It seems to me that your purpose here is simply to be an irritant, rather than to discuss the science in good faith. I see no point in trying to discuss anything with you any further.
Yes, that's true, Russ. y = 1.6%. And z = the number of papers that quantify and find less than 50%. z = ~.03% (and a mighty sketchy 0.03% at that). What's your point?
Dikran Marsupial,
No, but it does require them to be climate-related. Papers deemed to be "Not climate related" were supposed to be excluded.
I agree it would be ideal to exclude all the "known to be incorrect papers". You'd need to build that into the screening and rating process, (and I don't know how that could be done objectively). But that quality filtering was not done here.
Sorry Russ, too little, too late. I am not interest in discussing science with someone who appears out to deliberately antagonise, even if they occasionally intersperse their bad behaviour with more sensible comments.
This page was linked in a page I found on Reddit. I don't understand how there can be arguments about this. Categories 2&3 have tons of papers which don't quantify the human contribution. One such paper only says:
http://link.springer.com/article/10.1007%2FBF00336375
Another
http://iopscience.iop.org/0741-3335/33/13/004/
Methane is "implicated in global warming." Global warming a "possibility." How can anyone claim these quantify the human contribution? They don't. Neither do hundreds of other papers in these categories.
[RH] Ask yourself if either of these papers "[Imply] humans have had a minimal impact on global warming..." per the category definitions stated in Cook13. There are 8 "baskets" in which you can place a paper. Read them and see which basket you would put these papers in.
Better yet, look at the menu bar above and you can start rating papers for yourself and see what results you come up with.
RH, why would I ask myself that? I never said those papers "[imply] humans have had a minimal impact on global warming." I said they don't quantify the human contribution. Accepting AGW without quantifying the human contribution means the papers could accept any value between 0 and 100%.
I read through 200 abstracts today. There are tons in Categories 2&3 which acknowledge AGW but don't quantify the human contribution. They are silent on the issue.
[RH] Clearly you have not read the Cook13 paper, because only categories 1 and 7 "quantify" human contribution. Please re-read the paper more clearly before continuing to comment on this issue. Any follow up comments need to acknowledge this and move forward. Any comments re-stating this error will be deleted.
Edit: If you do not like the methods used by Cook13 then you are highly encouraged to create your own research and submit to peer review. We would be eager to see your results.
Stepping back a bit from the repeated attempts to post hoc redefine the criteria actually used in the Cook et al paper (absurd), I find it utterly fascinating how stridently any expert consensus on AGW is being denied.
Look at other consensus objections: as with creationism, anti-vaccines, the entire tobacco industry campaign, ozone, acid rain, and now anthropogenic global warming - a repeating pattern of minority opinions trying to convince the public that the experts are not in agreement (when they actually are). Possibly because people without a relevant background will trust the majority opinion of the experts as being meaningful, and that shapes policy.
So - nit-picking on tiny aspects of papers that don't, that cannot, change the base conclusions of the science, fake experts (the 3%), the ad hominem attacks on authors in attempts to discredit their work, the contradictory counter-explanations du jour (the sun, cosmic rays, cycles, it's not happening, anything but us), on and on and on. And claims that the consensus doesn't exist, despite 'skeptic' attempts to claim a skeptical consensus does (the OISM petition). But a distinct lack of science - of attempts to examine the data and see if those minority opinions have any support from the evidence.
So why is consensus on AGW fought so much by the 'skeptics'? IMO it's because if 95-97% of those studying a topic agree, yet you vehemently disagree, you just might be fooling yourself... and people seem to find that intolerable.
Dikran Marsupial @328, there is a defacto exclusion of papers that are not related to climate by the inclusion of category 4:
Presumably the intention is to exclude opinions by non-physical scientists who are not only not necessarilly expert in a particular area of climate science, but do not necessarilly have the scientific background to assess the evidence adduced by the IPCC in support of the concensus position. Therefore we can conclude that a limited number of Duarte's very small list do represent genuine errors of classification.
What Duarte (or Russ R) have not established is the relevance of that. Of course there are errors of classification. The classifiers were human, and humans make mistakes. In so large an excercise with the classification of 12,465 papers there are bound to be a number of mistakes. It is well known, and easilly established that the largest single group of such mistakes is classifying rating (1-3) articles as rating (4) due to simple error or insufficient information in the abstract and title, something we know by comparison with the author self ratings. There are in the order of 3500 such "mistakes".
Given that there are bound to be such errors, both increasing and decreasing the consensus value, the only significant question is what is the effect of correcting those errors. For one class or errors (internal rating errors) it is now well established that it has no significant effect by Cook et al's response to Richard Tol's flawed critique. Duarte, and Russ R acting as Duarte's puppet, raise a different category of mistakes. They make no attempt to quantify relative proportions of such mistakes, either by count or statistically, and cherry pick mistakes only in one direction. However, simple analysis as above shows it is highly implausible that such mistakes will impact the result.
Another approach is to note that only 283 out of 12280 abstracts were rated as not climate related, ie, just 2.3%. Assume that twice that number escaped correct classification and all were rated as endorsing the consensus. With these utterly implausible assumptions, "correction" of the results would reduce the consensus rate from 97.1% to 97%.
Again this underlines the fact that simply finding an error of classification or rating does nothing as regards a scientific critique of Cook et al. With out quantification of the relevant ratios, and a projection of those ratios to determine the impact on the concensus rate, listing cherry picked examples of such errors is simply propaganda, haveing nothing to do with science.
Of course, I have laid out these points before @322. Russ R firmly established which side of the science/pseudoscience divide he is on by brushing them aside with an inane comment. Other than pointing that out, I will leave it there lest I also become guilty of excessive repetition.
Will Power @355, by the definitions of the rating categories, any paper rated 2 or 3 that does quantify the contribution explicitly and rated 2 or 3 is a mistake. Pointing out that those papers do not explicitly quantify the contribution is therefore not a criticism of the paper, and if you think it is it shows you have not understood it.
With regard to the two papers you consider, it is quite clear that they implicitly endorse the consensus. That is, their statements together with reasonable background knowledge strongly implies that the paper endorses the consensus.
That implication is inductive. It may be wrong. However, error analysis first conducted by Richard Tol, and then done correctly by Cook and others in their response to Tol clearly show that there are more errors in the opposite direction. Ie, if we corrected all such probable (or plausible) errors, more rating 4 abstracts would be rerated as 3 or higher, than rating 3 or higher abstracts rerated as 4. The net result would be to strengthen the consensus finding.
You are welcome to disagree with that finding, but if you do you need to quantify the proportion of such mistakes in both directions (and also as related to rejection papers). Failure to do so renders your critique merely rhetorical. Ideally you would replicate the paper, but make sure your replication includes the element of author self rating as a check on your abstract rating bias.
Well said KR @337.
It seems one of my comments didn't go through. RH, I have read the paper. I don't disagree with anything you say about it. You say "only categories 1 and 7 'quantify' human contribution." If only Categories 1&7 quantify the human contribution, Categories 2&3 cannot quantify the human contribution.
That means I accept with everything you say about the paper.
[RH] Your previous statement was, "I read through 200 abstracts today. There are tons in Categories 2&3 which acknowledge AGW but don't quantify the human contribution. They are silent on the issue."
Papers that are in 2&3 are not expected to quantify AGW. They only need to implicitly endorse the consensus position.
Please re-read Cook13 more carefully before proceeding to comment.
With respect to Will Power @335, the title and abstract of the first abstract from which he quotes read as follows:
I have placed in italics the portion he quoted, and underlined the portions most relevant to the classification. It is my opinion that interest in the reduction of greenhouse gases, the only criteria under which the treatment was tested, is only relevant if greenhouse gases are the major contributor to global warming, and only a recommendation of greenhouse gases are the major contributor to global warming. Hence implicitly the abstract assumes that greenhouse gases are the major contributor to global warming (which is also implicitly assumed to be a bad thing). As background, the anthropogenic origin of the recent increase in greenhouse gases is so well established that rejection of it ranks with rejection of heliocentrism in terms of scientific credibility. Ergo acceptance of greenhouse gases as the major contributor to global warming strongly implies that anthropogenic causes are the major contributor to recent warming. Without that assumption (and hence tacit endorsement), the paper is as of much scientific interest as 19th century papers about how long it takes for ants to wander outside circles of specific diameter.
For the second abstract, here are the title and full abstract:
Again I have italicized the portion quoted, and underlined the relevant portion. From the abstract the article examines whether or not increased greenhouse gases will cause climate change. Further, it goes on to explore ways of ameliorating climate change by reducing emmissions of greenhouse gases. Clearly, therefore, it found that increased GHG do cause climate change, and that they cause it at sufficient quantities as to require amelioration. Given this information it is possible, though unlikely, that they found greenhouse gases cause global warming at sufficient rate only to cause 45% of recent warming, but it is far more likely that they found warming at a sufficient rate to cause >>50% of warming. Again, this is an inductive conclusion that may be wrong - but it is unlikely to be so and as previously noted, errors from neutral to endorsement have been shown to be outnumbered by errors in the reverse direction.
RH, I'm confused. I guess my comment did go through. What point do you want me to acknowledge? My comment specifically agreed with everything you said in your response to me. It seems clear we agree papers in Categories 2&3 do not quantify the human contribution. Is that right? Can everyone accept that and move on?
Can we all agree, "Categories 2&3 don't quantify the human contribution but do endorse the consensus"?
Did you mean to say implicitly or explicitly/implicitly? I thought only Category 3 was for implicit endorsements?
[RH] My error: Cat 2 explicitly endorses human caused warming, without quantification. Cat 3 implicitly endorses human caused warming, without quantification. Neither requires quantification.
Your original statement suggested that tons of 2&3's don't quantify, which is what is expected for papers found in those categories.
I would encourage everyone to read (or reread) section 4.1 of our paper "Sources of uncertainty". Many of the problems that our critics think they have uncovered were previously acknowledged there. Perhaps this is a sign that they never actually bothered to read it.
Yes, the abstract rating process was often subjective and the results were noisy. We frequently disagreed amongst ourselves. There will be instances where the final ratings can be reasonably disputed. It would be great to see this work redone by a different team.
The fact remains that very few papers and fewer abstracts reject the consensus on AGW. I was thrilled whenever I found one. Reading thousands of abstracts that endorsed or were neutral on AGW did get a little boring and finding a real dissenter brightened my day. It turns out there were just 78 rejections out of 11944 abstracts. Finding a real one could take hours of patient slogging.
Rejection of the basics of AGW in the scientific literature is a fringe activity. If your worldview hinges on there having to be significant doubt among experts about the basic science, it is understandable that this can be a hard fact to swallow.
Will Power @343, saying "papers in Categories 2&3 do not quantify the human contribution" is ambiguous. Papers in those categories do not explicitly quantify the contribution by definition of the category. They may still endorse (explicitly or implicitly) that >50% of recent warming is anthropogenic. An example of an explicit endorsement without quantification would be "while anthropogenic forcings continue to rise, combined natural forcings are negative over recent times, and internal variability is small" from which it is readilly deduced that anthropogenic factors are the primary cause of recent warming, without being able to quantify whether they contribute 55% or 110%, or something in between. Another example of explicit endorsement without quantification is "The IPCC shows global warming to be a substantial threat to human civilization". (It is irrelevant to the case whether they actually do show that, so please don't get distracted.) Such a statement endorses the (purported) IPCC findings, and therefore endorses basis of those findings, including that anthropogenic factors have contributed more than 50% to recent warming.
Because the abstract ratings in Cook et al attempt to quantify a quantitative factor (">50% or recent warming") using non-quantified data, that increases the risk of errors but several tests including the self ratings have shown the errors not to have effected the results. That is, they are more likely to have rated as neutral papers that do endorse the consensus than the reverse (as is shown by statistical analysis of internally detected error rates, and by comparision with the author self ratings). Unless you can show by statistical analysis or by replication that those two tests of relative error rates are in error, bringing up short lists of supposed errors is mere cherry picking, and rhetorical rather than scientific criticism.
Let me see if I understand the disagreement correctly. Everyone agrees Category 1 quantifies the human contribution, but Categories 2&3 do not. The disagreement is Russ R feels that means we should describe the results by saying:
The other view says we should say:
Because while Categories 2 and 3 don't directly quantify the human contribution, they do endorse the idea it is >50%.
Am I misunderstanding one side of this, or can can everyone agree that description of the positions is right?
[RH] This is not a matter of disagreement. The fact is, categories 1-3 endorse human contribution and categories 5-7 minimize human contribution. Cook13 also went the additional step to be self-skeptical of potential bias that could have been introduced by raters (as Andy Skuce aptly pointed out with section 4.1, and Tom Curtis has repeated pointed out), by asking scientist to self-rate their own research. Thus, Cook13 has two independent measures that agree, which also agree with the results of previous research by Oreskes, Doran&Zimmerman and Anderegg.
This makes Russ' description wrong.
RH, you can say it isn't a point reasonable people can disagree about, but it seems abundantly clear it is a topic people do disagree on. I think it'd be good to clarify exactly what they disagree about. You can't do a good job explaining how a person is wrong if you don't explain what they say.
In that vein, am I right to say Russ R thinks this is an appropriate description of your results:
And you guys say that statement is wrong, that it misrepresents your results?
[RH] It is a misinterpretation of the results.
Will Power @346, incorrect. Specifically, "the AGW theory" is, in its simplest form, that:
a) humans have caused most of recent warming,
b) continuing as we have will result in a very significant warming, and
c) warming is likely to cause significant adverse consequences. Therefore Russ R's position as stated by you is incoherent. Specifically, if 97% there is "a 97% consensus supporting AGW theory", then there is also a 97% consensus supporting the claim that humans have caused most of recent warming.
Russ R's position should be restated that "there is a 97% consensus supporting that anthropogenic factors have caused some (>0%) of recent warming; and 1.6% supporting that most (50% or more) of recent warming has been anthropogenic". That position, however, is also incoherent as shown in my post at 318 , which I recommend you read if you have not done so already.
Finally, it is sometimes said that Cook et al show there is a 97% concensus behind the theory of AGW, or the IPCC. In fact it does not. Certainly it shows (as much as any empirical study can) that there is a 97% concensus behind (a), and by implication also behind (b). However, some small part of the scientific community accept (a) and (b) without accepting (c), and (c) was not specifically tested for in the survey. There may also be a 97% consensus behind (c), but Cook et al have not shown it.
That strikes me as somewhat defensive, and unusual. I don't think I have ever seen that as a response to criticism of a paper elsewhere.
A person does not need to replicate research to comment positively or negatively on results and interpretation. The people who wrote the paper can choose to respond or not. They aren't obligated either way. I can write a criticism of a paper if I think they've interpreted something incorrectly, like an NMR or FT-IR spectra, or notice something they missed. Someone could suggest a different restriction enzyme or method in biochemistry, etc... etc... without doing the research again.
For instance, when I first read the Cook paper, and in particular, the author self-rated portion, I found myself curious about the people's thoughts on the question, even if they rated their own papers as not taking a position. And in the politics of it, "people" and "papers" seem to be interchanged cavalierly. I would note that because the issue of politics is a large one on the topic, a great deal of scientists (addressed with the drama effect discussion a little) might studiously avoid quantification, or even mentioning "global warming" or "global climate change" so as not to get dragged into defending their paper on a political, rather than scientific basis. I would think most scientists are interested primarily in the science, not the politics, and for them the question of consensus might be interesting, but less important. I think the lack of understanding of the rating system and what it means speaks possibly to a lack of clarity. I find myself wondering how well the raters themselves understood it (particularly in light of the 33% initial disagreement between them), or even the scientists invited to self-rate their papers. Maybe something to consider for follow-up, if any. And I can't for the life of me figure out why both the people and papers that didn't take a position, explicit or otherwise are considered not part of it. To a scientist, the answer "I'm not sure." is a perfectly valid answer, especially if they aren't actually sure. :)
Tom Curtis @348,
Citation needed.
What you've described above is more commonly known as CAGW theory, the "C" standing for "Catastrophic". And I'm skeptical.
In it's simplest form, AGW theory consists of exactly three things. Anthropogenic, Global, & Warming. i.e. that human activity causes the planet to warm. That's all. It's a theory which has an abundance of supporting evidence, and with which I am entirely in agreement. And that's the full extent of the "consensus" which has been tested and confirmed. None of the "consensus research" has investigated views on future impacts.
[RH] This is off topic for this thread. Move it to an appropriate thread.