David R. Henderson  

About That 97 Percent

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I've posted before (here and here) about the John Cook study that purports to find that 97% of climate scientists believe that humans are the main cause of global warming.

Now Richard Tol, a professor of the economics of climate change, has written a further critique of the Cook study.

Some highlights:


Some have claimed that Cook et al. found a consensus on the dangers of climate change (Kammen, 2013) or on the need for climate policy (Davey, 2013). They investigated neither. Even some of the authors of the paper misrepresent its findings (Nuccitelli, 2014, Friedman, 2014, Henderson, 2014).

Cook et al. took a sample of the academic literature and rated its contents. The raters were recruited through a partisan website (Cook et al., 2013) and frequently communicated with each other (Duarte, 2014). Their sample is not representative of the literature (Tol, 2014a). The sample was padded with large numbers of irrelevant papers (Tol, 2014a). For example, a paper on photovoltaics in Kenya (Acker and Kammen, 1996) was taken as evidence that climate change is caused by humans as was a paper on the coverage of climate change on US TV (Boykoff, 2008). Three-quarters of the "endorsing" abstracts offer no evidence either way (Tol, 2014a). Their attempt to validate the data failed (Tol, 2014a). An attempt to replicate part of the data failed too (Legates et al., 2013). The data show inexplicable patterns (Tol, 2014a) while the consensus rate suffers from confirmation bias (Cook et al., 2014a, Tol, 2014b).


in sum, one of the most visible climate papers of recent years is not sound. Whereas previous critique could be interpreted as a lack of competence (Tol, 2014a), the later data release suggests that Cook et al., perhaps inadvertently, worked towards a given answer. This reflects badly on the authors, referees, editors and publisher. It also weakens the activists and politicians who cite Cook et al. in support of their position.

BTW, I'll be forever grateful to Richard Tol for coining the phrase "sunk benefit." (I assume he coined it.) He mentions it here.

HT to Robert P. Murphy.


Comments and Sharing






COMMENTS (13 to date)
MG writes:

In the comments section of one of your previous posts, Daniel Kuehn raised the bar on some of the criticsm being levied on the paper and the authors.

"I'm not sure that was the intent of the authors. How do you know that? I'm guessing they weren't careful in making that claim about the study (or someone else wasn't - it's amazing how easily communications departments miscommunicate). The study seems careful enough from what everybody's been reporting. I don't know the guy - I don't feel comfortable making that sort of claim about him."

I think Richard Tol has cleared it.

David R. Henderson writes:

@MG,
Thanks for that reminder.

Peter writes:

This is funny.

Tol writes a critique paper of Cook(2013), submits it to ERL and gets rejected with reviewers pointing out 2 dozen errors. Instead of fixing the errors he shops it around until some journal (energy policy) finally publishes it. Cook responds to Tol's paper also pointing out 24 errors, and shows that Tol's arguments actually re-confirm the 97% consensus. Tol then tries to publish a "perspective" piece in ERL just re-hashing the arguments in his error riddled paper. ERL again rejects it because duh. Tol publishes it on his website so uninformed people can cling to it.

After this and his error filled JEP article, he's running a bit low on credibility.

Just hilarious.

David R. Henderson writes:

@Peter,
How do you know it was rejected by ERL? Does ERL not use blind referees? Or were you one of the referees?

Peter writes:

Here:

http://archive.today/p8VxA

Dan writes:

The most devastating critique of the Cook study of which I'm aware is by Jose Duarte. There are a bunch of blog posts of his on the topic, but here is a good place to start:

http://www.joseduarte.com/blog/the-art-of-evasion

Daublin writes:

Peter, Tol's critique seems to hold up to me. For example, I don't think you should recategorize your data if it doesn't come out the way you wanted. You also shouldn't have your coding people ("raters") collaborating with each other, or else they'll start to group think.

Cook is known to have done both of those things. Do you want to argue that it's good science to behave this way? Or do you want to say that only a domain expert is qualified to talk about these matters?

These are basic scientific procedures. If you don't follow them, you can prove whatever you feel like proving. Peer review can help if it's one person alone doing it, but as soon as you have one or two professor friends in your area, you can just favorably review each other's papers.

genauer writes:

As somebody who comes here only occasionally,

I want to explicitely thank you for keeping this topic burning

It lead me to look at a lot of the links mentioned here, and as being an old grumpy german physics PhD

I found those 2 most important:

Steve Koonin http://online.wsj.com/articles/climate-science-is-not-settled-1411143565

http://judithcurry.com/2014/10/31/bertrand-russells-10-commandments/
encourages me to open my mouth and not take the
Greenie intimidation any longer

Peter writes:

It doesn't.

Tol's basis for arguing the raters were not independent is an out of context and mischaracterized stolen email.

I find it difficult to describe this as anything other than blatantly dishonest...or maybe it was gremlins again...

On a related note, I usually try to assume the best in people, but at what point do you just have to give in and admit someone might not be acting in good faith?

William Newman writes:

[Comment removed for supplying false email address. We have tried to reach you several times. This is your final notice. Email the webmaster@econlib.org to request restoring your comment privileges. We'd be happy to publish your comments. A valid email address is nevertheless required to post comments on EconLog and EconTalk.--Econlib Ed.]

Mark Bahner writes:
The study seems careful enough from what everybody's been reporting.

The paper is very, very bad:

Some abstracts ridiculously claimed to show global warming is caused by humans

But it's the misrepresentation of the paper's findings by the authors that is deliberately dishonest:

"97 percent of climate papers stating a position on global warming agree--global warming is happening and we are the cause"

Mark Bahner writes:
Tol writes a critique paper of Cook(2013), submits it to ERL and gets rejected...

Environmental Research Letters (ERL) published the original Cook et al. paper, and are happy to see its results misrepresented across the Internet, so they have no credibility.

Mark Bahner writes:
On a related note, I usually try to assume the best in people, but at what point do you just have to give in and admit someone might not be acting in good faith?

Yes, Peter, at what point will you just give in and admit that Cook et al. are shamelessly lying about the results of their paper?

"97 percent of climate papers stating a position on global warming agree--global warming is happening and we are the cause"

?

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