A Climate Falsehood You Can Check for Yourself

Most of the information relevant to arguments about climate, as about many other things, is obtained at second, third, or fourth hand, with the result that what you believe depends largely on what sources of information you trust. People on either side of an argument can honestly believe that the evidence strongly supports their view since they trust different sources and different sources report different evidence. It is thus particularly interesting when on some point, even a fairly minor one, you can check a claim for yourself.

Here is an example.

Cook et. al. (2013) is the paper, possibly one of two, on which the often repeated claim that 97% of climate scientists believe in global warming is based. Legates et. al. (2013) is a paper which criticizes Cook et. al. (2013). Bedford and Cook (2013) is a response to Legates et. al. All three papers (the last a pre-publication version) are webbed, although Legates et. al. is unfortunately behind a pay wall.

Bedford and Cook (2013) contains the following sentence: "Cook et al. (2013) found that over 97% endorsed the view that the Earth is warming up and human emissions of greenhouse gases are the main cause."

To check that claim, look at Cook et. al. 2013. Table 2 shows three categories of endorsement of global warming reflected in the abstracts of articles. Category 1, explicit endorsement with quantification, is described as "Explicitly states that humans are the primary cause of recent global warming." Category 2 is explicit endorsement without quantification. The description, "Explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a known fact" is ambiguous, since neither "causing" nor "anthropogenic global warming" specifies how large a part of warming humans are responsible for. The example for the category is clearer: 'Emissions of a broad range of greenhouse gases of varying lifetimes contribute to global climate change.' If human action produces ten percent of warming it contributes to it, hence category 2 does not specify how large a fraction of the warming humans are responsible for. Category 3, implicit endorsement, again uses the ambiguous "are causing," but the example is '...carbon sequestration in soil is important for mitigating global climate change,' which again would be consistent with holding that CO2 was responsible for some but less than half of the warming. It follows that only papers in category 1 imply that "human emissions of greenhouse gases are the main cause." Authors of papers in categories 2 and 3 might believe that, they might believe that human emissions of greenhouse gases were one cause among several.

Reading down in Cook et. al., we find "To simplify the analysis, ratings were consolidated into three groups: endorsements (including implicit and explicit; categories 1–3 in table 2)." It is that combined group, ("endorse AGW" on Table 4) that the 97.1% figure refers to. Hence that is the number of papers that, according to Cook et. al., implied that humans at least contribute to global warming.

A commenter on my blog located the data file for Cook et. al. (2013). The number of articles classified into each category was:

Level 1 = 64

Level 2 = 922

Level 3 = 2910

Level 4 = 7970

Level 5 = 54

Level 6 = 15

Level 7 = 9

The 97% figure was the sum of levels 1-3. That 97% breaks down as:

Level 1: 1.6%

Level 2: 23%

Level 3: 72%

Only Level 1 corresponds to "the Earth is warming up and human emissions of greenhouse gases are the main cause." It follows that the sentence I quoted from Bedford and Cook is false. Cook et. al. did not find that "over 97% endorsed the view that the Earth is warming up and human emissions of greenhouse gases are the main cause." (emphasis mine). He found that 1.6% did. It is possible, indeed likely, that more do, but that was not what the article found.¹

In online exchanges on climate, I repeatedly encountered the claim that 97% of climate scientists believed humans were the main cause of global warming. That included an exchange with one of the very few reasonable and civil supporters of the claim that global warming would be catastrophically bad that I encountered in the online arguments, where most participants on either side are neither reasonable nor civil.

The paper appears designed to encourage that misreading by lumping together categories 1-3 and reporting only the sum. It repeatedly refers to "the consensus" but the closest it came to defining that is as the "position that humans are causing global warming" — which leaves it unclear whether "causing" means "are one cause of," "are the chief cause of," or "are the sole cause of." To discover that it meant only the former a reader had to pay sufficiently careful attention to the details of the paper to notice the examples for categories 2 and 3, which few readers would do. The fact that Cook chose in a second paper to misrepresent the result of the first is good evidence that the presentation of his results was deliberately designed to mislead. Hence the sentence in question is a deliberate lie, a fact that any interested reader can check by simply comparing the two papers of which Cook is a co-author, both webbed.

That Cook misrepresents the result of his own research does not tell us whether AGW is true or how dangerous it is. It does not even tell us if most climate scientists believe that humans are the main source of climate change. But beliefs on either side depend largely on what sources of information you trust and I have now provided unambiguous evidence, evidence that anyone who is willing to carefully read Cook (2013) and check what it says against what Bedford and Cook claims it says can verify for himself, that John Cook is willing to deliberately lie in print about his own work.

The blog Skeptical Science lists John Cook as its maintainer, hence all claims on that blog ought to be viewed with suspicion and accepted only if independently verified. Since, as a prominent supporter of the position that warming is primarily due to humans and a very serious threat, Cook is taken seriously and cited by other supporters of that position, one should reduce one's trust in those others as well. Either they too are dishonest or they are unduly willing to believe false claims that support their position.

The fact that one prominent supporter of a position is dishonest does not prove that the position is wrong. For all I know, there may be people on the other side who could be shown to be dishonest by a similar analysis. But it is a reason why those who support that side because they trust its proponents to tell them the truth should be less willing to do so.

Cook’s Response

John Cook eventually responded to my criticism, not on my blog but on the comment thread of one that linked to mine. He wrote:

As lead author of the Cook et al consensus paper, I can demonstrate how David Friedman ginned up a false contradiction by quoting me out of context. Here is the full line from the Bedford & Cook paper:

Of the 4,014 abstracts that expressed a position on the issue of human-induced climate change, Cook et al. (2013) found that over 97 % endorsed the view that the Earth is warming up and human emissions of greenhouse gases are the main cause.

To generate the 'contradiction', Friedman omits the first portion of the sentence:

Cook et al. (2013) found that over 97 % endorsed the view that the Earth is warming up and human emissions of greenhouse gases are the main cause.

I agree entirely with the OP's assertion of checking what writers say and see what their statements are based on. In this case, Friedman's criticism is based on misrepresentation of my original text. I find it extraordinary that Friedman accuses me of a deliberate lie while misquoting my work (deliberately? You decide). It is also ironic that a theme of this post is checking writing for falsehoods while uncritically repeating his misrepresentation.

That would be a legitimate response if my criticism had been of the fact that his 97% figure ignored the roughly two-thirds of papers whose abstracts took no position on AGW. But, as you can easily check from my blog post, that is not what I objected to. My objection was that the 97% figure lumped together categories 1-3 when only category 1 fitted Cook's "main cause." Category 1 contained 64 papers, 1.6% not 97%. Cook indignantly responded to a criticism I did not make, ignored the criticism I did make, and offered a defense entirely irrelevant to my criticism.

That left me with a puzzle — was he a rogue or a fool? was he trying to mislead careless readers who, by the time they had gotten to his response, had forgotten what my criticism was, or readers sufficiently committed to his side that they would assume what he wrote was true without bothering to check either my post or David Henderson’s account of my argument? Alternatively, is he so incapable of reading and understanding criticism that he confused the point about the two thirds who expressed no opinion, raised by David Henderson in his piece commenting on mine, with my argument which David Henderson accurately reported? Is he unaware of the trick he himself pulled by pooling the three categories and reporting only the sum? It seems hard to believe. What, after all, was the point of separately looking at the three categories if he was not going to report the results?

One piece of evidence in favor of the rogue theory is that he posted his response on David Henderson’s blog instead of mine, making it less likely that readers of it would have read my post. One piece of evidence in favor of the alternative is that he offered a transparently fraudulent rebuttal to my argument instead of remaining prudently silent.

It is not surprising if there are some dishonest people on one side, the other, or both of the climate controversy. A more interesting question is whether there are any honest people. Are there any prominent supporters of the need for strong action to prevent warming who have publicly rejected Cook et. al. 2013 or its author?

The closest I have found is Richard Tol, a Dutch economist who was one of the IPCC authors and has webbed his own criticisms of Cook et. al 2013. Tol, however, has published estimates of the cost of warming suggesting that it is negative at low levels and positive but not catastrophic at high levels and eventually resigned from the IPCC in protest against some of its positions. Although he almost certainly believes that warming is real and in large part anthropogenic, as do I, he cannot be counted as clearly on Cook’s side of the argument.

I may have missed someone but so far, assuming I have not made a mistake in the analysis so far, there appears to be nobody on Cook’s side of the climate argument who is sufficiently concerned with truth to have noticed, and publicly reported, that a much quoted factoid on his side is a lie.

1.6%→97%: Hasenpfeffer

Diner: "Waiter, it says hasenpfeffer on the menu. Is it really rabbit?"

Waiter: "Yes, sir."

Diner (suspicious): "All rabbit?"

Waiter: "There's a little veal in it too."

Diner (still suspicious): "How much veal?"

Waiter: "Fifty-fifty."

Diner: "Fifty-fifty? Just what does that mean?"

Waiter. "Fifty-fifty. One of each."

1. Adding up categories 5-7, the levels of rejecting of AGW, we find that more papers explicitly or implicitly rejected the claim that human action was responsible for half or more of warming than accepted it, according to Cook's data.