Remarkable Remarks by Cook et al

There was apparently an AMA on Reddit yesterday with the authors of the recent Cook (2016) paper I've recently discussed. I missed out on it, which is a shame even though I expect I would have just been censored. Oh well. At least we get to see what the authors of the paper have to say about their work.

That's what this post will be for. I'm going to just highlight comments by these authors I see which seem remarkable and give a brief description of what is noteworthy about them. Feel free to do the same in the comments section.

A user asked this about the Cook (2013) paper which claimed to find a 97% consensus:

I think what may be the case without looking into it is that some believe anthropogenic warming to be a factor, but not the major factor in our warming (a question for the researchers here - would these people be included in the 97% figure?).

An author of both Cook (2013) and Cook (2016), Peter Jacobs, said:


This response is interesting as anyone who spends any time looking at the ratings of the papers rated as endorsing the "consensus" will find nearly none of them quantify it (look for yourself). Of you could look at the authors own words when they designed the rating system, where they described categories two and three:

2 Explicitly endorses but does not quantify or minimise AGW
3 Implicitly endorses AGW without minimising it (by definition does not quantify)


John, I think it would help to add "does not quantify or minimize AGW" to category 2 and 3, just to make the distinction between the categories clear. Otherwise if you get a paper that endorses but also minimizes AGW, technically it could go in multiple categories. Don't want to confuse people or have category overlap.

This means Peter Jacobs was wrong as any abstract which found "anthropogenic warming to be a factor" would be rated as endorsing the consensus as long as it did not explicitly state anthropogenic warming was "not the major factor in our warming." That would be why John Cook wrote this in a response in the AMA:

We didn't make any assumptions about what scientists thought - rather, we looked at their published words in the abstracts of their scientific papers. If the abstract stated a position on human-caused global warming, then we noted whether it endorsed or rejected it. We found that among the ~4000 abstracts stating a position, 97.1% endorsed human-caused global warming.

Notice how he says "97.1% endorsed human-caused global warming." He says knowing fully well that 97.1% did not endorse the idea humans are the main cause of global warming. Yet he also says:

Actually, there are a number of different definitions of consensus used throughout the studies - some look at humans causing most of global warming, others look at humans causing global warming (which implies a large or dominant portion), others look at humans contributing without specifying the percentage. Regardless of the definition used, there is overwhelming consensus among climate scientists.
To give a precise example, in our 2013 paper, we asked scientists to rate their own climate papers. Among papers that were self-rated as stating a position on whether humans were causing most of global warming, around 96% endorsed the consensus position.
So I'm afraid its your characterisation of our research that is the straw man.

This claim simply isn't true. There is no way to justify this claim. What Cook has done is compare results for only Category 1 and Category 7, claiming that shows the result he promotes here. The problem with that is Categories 5 and 6 say:

5. Implicit Rejection of AGW

Discusses other natural causes as being dominant influences of recent climate change without explicitly mentioning AGW
6. Explicit Rejection of AGW without quantification

Explicitly rejects or minimises anthropogenic warming without putting a figure on it.

If a paper "rejects or minimises anthropogenic warming" and even "[d]iscusses other natural causes as being dominant influences of recent climate change," it obviously rejects the idea humans are the main cause of global warming. If you include those in the comparison, the result drops from 96.2% to 85.8%. Cook was only able to give this answer by pretending a paper which claims natural causes are the dominant influences on recent climate change don't reject the idea humans are the main cause of recent warming.

Then there is a lengthy comment which highlights the conflation of the idea humans cause some amount of warming with the idea humans are the main cause of warming, discussing the individual categories and the number of abstracts assigned to them. John Cook responds:

Thanks for this (lengthy) comment. It neatly encapsulates the key flaw of criticisms of Cook et al. (2013) - the unwillingness of critics to consider the self-rating survey that replicated the 97% consensus. To my knowledge, every criticism of our research has studiously avoided the self-rating replication.
To give a quick overview of Cook et al. (2013) (freely available at, we first estimated the scientific consensus by categorising the abstracts of scientific papers about global warming. We identified ~4000 abstracts stating a position on human-caused global warming - amongst those abstracts, 97.1% endorsed the consensus.
Next, and here is the crucial part that every critic of our paper has conveniently ignored or avoided, we replicated our result by inviting the authors of the scientific papers to rate their own research. If we had mis-characterised a significant number of papers (e.g., rated them as endorsing AGW when they didn't), then there would've been a significant discrepancy between our abstract rating and the self-rating. 1200 scientists responded to our invitation, resulting in over 2000 papers receiving a self-rating. Amongst papers that were self-rated as stating a position on human-caused global warming, 97.2% endorsed the consensus.

There's more, but the remarkable thing is Cook's entire response has nothing to do with what the user said. Cook wrote six paragraphs criticizing critics of his paper because they "refuse to take a step back and look at the full study, with independent methods replicating the finding of an overwhelming consensus on climate change." Of course, this does nothing to address criticisms of the rating system he used in both of the "independent methods" he refers to here.

That comment was linked to by Peter Jacobs as well:

I can't speak to the ban itself, but it looks like a bunch of people spammed the same copypasta they stole from a two year old blog post.
John Cook answered it here:
-- Peter Jacobs

Even though anyone who reads the two links can easily see the comment I quoted (part of) by John Cook does nothing to address the argument made in that post. It appears both John Cook and Peter Jacobs are insisting the self-rating by authors using the same rating system as the Skeptical Science ratings used proves the rating system doesn't have any problems because the methods used with the self-raters are "independent."

I think I'll just end this post on that note. It hurt my head too much to write it. Feel free to contribute any quotes from the Cook et al authors you found interesting, whether they be from this AMA or somewhere else.


  1. Right after submitting this post, I came across an exchange that perfectly encapsulate the problem with the Cook et al (2013) paper. John Nielsen-Gammon wrote:

    Is global warming happening? Absolutely! 98%-99%
    Are we an important cause? Yes! 85%-93%
    Are we “the” cause, as in is it mostly human? Yes. 75%

    It was impossible for your abstract survey to distinguish between the second and third item above.

    John Cook responded:

    I wonder, have you read our paper? We categorised papers by whether they endorsed human-caused global warming without quantification (the second item above) and whether they quantified the human contribution to global warming as more than half (the third item above). So we did exactly what you say was impossible for our abstract survey – distinguished between the second and third item above.

    We took that approach because different abstracts expressed endorsement of human-caused global warming in different ways. So we categorised the abstracts according to different expressions of consensus. But we found that regardless of the definition of consensus that you used, there was overwhelming agreement.

    This shows Cook knows fully well his Categories 2 and 3 do not endorse the idea humans are the main cause of global warming. This response sums things up:

    To be clear and to correct my previous statement, you categorized papers by whether they quantified the human contribution in your research methodology, but chose to lump both groups together when you presented your results. Thus your survey distinguished between those two possibilities but your paper did not.

    That is the central problem with the Cook et al (2013) paper John Cook authored. Yet no matter how many times people point it out to Cook, he doesn't do anything to respond to it (though he does sometimes misrepresent what they say and pretend to have responded to their criticisms).

  2. "here is the crucial part that every critic of our paper has conveniently ignored or avoided, we replicated our result by inviting the authors of the scientific papers to rate their own research"

    I wrote repeatedly about this. Perhaps I'm not a critic, but I did note that the two ratings strongly disagree.

  3. I know both I and lucia of The Blackboard have pointed out the self-ratings do nothing to address problems with the rating system. I know others have as well. The idea John Cook's critics have "conveniently ignored" the self-ratings is pure fantasy.

Comments are closed.