97 percent climate consensus? Analysis of the second part of the Cook study

Introduction

In the last article I talked in detail about the Cook study “ Quantifying the consensus on anthropogenic global warming in the scientific literature ” from 2013 and its very creative use of numbers.

Overall, I came to the following conclusion from the first half of the Cook study:

of agreement with the thesis that humans are largely responsible for climate change In 99.46% of all scientific papers there is no evidence . Many consider the human share to be smaller or do not make a clear statement about it. The vast majority of more than 66% make no statement on this question. A small number even clearly reject a predominant or at least significant human contribution to climate change.

Only 0.54% of all publications claim that humans play a predominant role in climate change.

In addition, the study's database is flawed; numerous publications are classified into incorrect categories, which resulted in a random sample. If we examine it again, this could shift the determined proportion of publications significantly in favor of the majority of people who reject it.

 

Because this result does not agree with the summary statement of Cook et al. agreed that a full 97.1% of all papers agreed with the “climate consensus” of predominantly man-made climate change, it was worth publishing on it . The 14 A4 page article was exceptionally published as a guest article on anti-spiegel.ru.

Thomas Röper from Anti-Spiegel.ru has now confirmed to me that my article is the most read article on his site. Because of the strong public interest alone, it is worth delving further into the topic, which is what I am doing here.

Mistake

With so many readers, it is understandable that I received many letters. In addition to a lot of encouragement, there were also some critical letters that rightly complained that I had made mistakes myself when reclassifying scientific publications.

These errors have now been corrected in the tabular summary of the abstracts in the article on my homepage and have been incorporated into the updated article. The corrections at the end of the article were also documented there.

The old article can be viewed in its original form at “anti-spiegel.ru” .

 

Wrongly translated into German?

Another criticism was that I used the consent groups from Cook et al. and a quote from the “Consensus Handbook” was incorrectly translated or that the translation in the German version of the handbook was incorrect.

Unfortunately, these points of criticism are not even remotely correct.

The consent categories I translated come from the raw data set from the Cook study. In terms of content, these do not differ from the consent categories in the published study.

There is also controversy over the following sentence from the introduction to Cook's study:

Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming. 

Does this sentence now translate as:

Among abstracts expressing a position on man-made or anthropogenic global warming (AGW), 97.1% support the consensus that humans are causing global warming.

(Automatic translation by Google Translator)

Or should it say:

Among abstracts expressing a position on man-made or anthropogenic global warming, 97.1% support the consensus that humans are causing global warming.

(This only refers to part of global warming)

Indeed, Cook et al. not clear here.

However, if you compare this statement with other statements from the German translation of the “ Consensus Manual ” authorized by Cook, then you will find very clear formulations on this question:

For example the quote:

97% of climate scientists have concluded from the evidence that humans are causing current climate change.

Cook, J., van der Linden, S., Maibach, E., & Lewandowsky, S. (2018). The Consensus Handbook. DOI:10.13021/G8MM6P. Page 1. Emphasis by the author.
Available at http://www.climatechangecommunication.org/all/consensus-handbook/

or but:

Communicating the current state of scientific consensus (97%) not only increases the perceived consensus. It also increases acceptance of the fact that global warming is real, man-made and a serious problem.

Cook, J., van der Linden, S., Maibach, E., & Lewandowsky, S. (2018). The Consensus Handbook. DOI:10.13021/G8MM6P. Page 18. Emphasis by the author.
Available at http://www.climatechangecommunication.org/all/consensus-handbook/

Now one could argue that the translator once again made errors. But you can't leave it like that. Because we read, among other things, the following in the German version of the manual:

German translation: Bärbel Winkler, Timo Lubitz, Thomas Traill

Cook, J., van der Linden, S., Maibach, E., & Lewandowsky, S. (2018). The Consensus Handbook. DOI:10.13021/G8MM6P. Page 0.
Available at http://www.climatechangecommunication.org/all/consensus-handbook/

The first mentioned Bärbel Winkler, who is listed here as the main person responsible for the translation, is the same Bärbel Winkler who also contributed to the study. A reader can assume that there is such a close exchange between Ms. Winkler and Mr. Cook that the most important and central statement of the study has been translated cleanly.

And John Cook and his team go one step further here.

“Let that melt in your cerebellar cortex,” Ken Jebsen would say at this point. Read the above quote carefully.

97% of climate scientists have concluded from the evidence that humans are causing current climate change.

 

So there would be a consensus that says that humans are not only responsible for the majority of climate change (i.e. more than 50%), but they are also THE responsible for climate change. Humanity would therefore be solely responsible for the entire global warming! That would correspond to 100% human influence.

This is a statement that the study by Cook and colleagues cannot provide with its methodology, because it asked a maximum of one consent group that attributed humans a share of over 50% in climate events. The study results in the handbook on the climate consensus are handled very flexibly here.

And the fear remains that this ambiguous and linguistically very sporty choice of words could be entirely intentional. I'll come back to this point at the end.

The central question remains:

Is it scientifically permissible to include the following three categories (or agreement groups) under the statement “Among the abstracts expressing a position on AGW (anthropogenic global warming), 97.1% support the consensus that humans are causing global warming. “to summarize?

(1) Explicit endorsement with quantification / Explicitly states that humans are the primary cause of recent global warming

(2) Explicit endorsement without quantification / Explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a known fact

(3) Implicit endorsement / Implies humans are causing global warming. E.g., research assumes greenhouse gas emissions cause warming without explicitly stating humans are the cause

Translated into German this would be:

(Please see the previous article for slightly different but identical wording from the raw data set .)

After checking category 2 with a non-representative sample of 98 papers, I can say with certainty that none of the abstracts I found say that the majority of climate change is caused by humans, and certainly not that 100% of climate events had human causes.

In category 3 we find even vaguer formulations. Here, too, there are apparently only scientific publications that somehow indirectly postulate a human contribution to climate change but do not say anything precise about the size of this contribution, or do not even explicitly mention humans as (one) cause (of many) of climate change. The latter were then interpreted by John Cook's team as meaning that there was a statement in favor of the climate consensus.

The bottom line is the sobering conclusion: No, it is not permissible to lump these three categories together.

This summary of categories 1 to 3 was probably only there to ensure the greatest possible number of scientific publications, contrary to all logic and truthful statements, under the sentence...

Among abstracts expressing a position on AGW, 97.1% support the consensus that humans are causing global warming.

Automatic translation by Google and correspondingly correct translation after comparison with the “Consensus Handbook”.

...to summarize. This is not a clean scientific approach and is a deliberate deception of the reader.

The second part of the Cook study

I made no reference to the second part of the Cook study in my first publication on the climate consensus.

The reason: I simply hadn't found any raw data at the time. “No raw data” automatically means that nothing can be checked here. I was criticized for not mentioning it, especially since the second part of the study would confirm the 97% consensus found in the first part. Apart from the fact that I pointed out the second part in all interviews, this accusation is in any case nonsense: I objected to the calculation method and the resulting result in the first part of Cook's work. Readers ignore the obvious errors in the first part of the study and simply claim that the second part confirmed the accuracy of the first part. Even if the second part were calculated correctly and led to the same result, that is not a confirmation of the result of the first part. But if the critics of my article had actually read through Cook's raw data for the second part beforehand...

Cook et al. claim to the second part:

In a second phase of this study, we invited authors to evaluate their own work. Compared to abstract ratings, a smaller percentage of self-rated papers expressed no position on AGW (35.5%). Among self-assessed posts expressing a position on AGW, 97.2% support the consensus.

Automatische Übersetzung, vgl. mit Cook et al.: Quantifying the consensus on anthropogenic global warming in the scientific literature. Enviromental research letters, 2013 IOP Publishing Ltd.
https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024

The credibility of this statement suffers from the fact that we already know that the first part of the Cook study on the climate consensus contains a completely misleading summary.

The basic rule in natural science is: results must be verifiable and repeatable under given conditions.

Verifiability also includes publishing the raw data for a work.

After my request for the first part of John Cook's work was ignored, I received a reply email within a few minutes after a written request for the raw data of the second part, which directed me to the following page:

https://skepticalscience.com/tcp.php

The raw data for the second part of the study can actually be found there.

https://skepticalscience.com/docs/self_vs_abstracts_private.txt

If you read through this data set you will find this here:

Year Abstract Self

1991 4 3,0000

1991 4 1,0000

1991 3 3,0000

1991 4 4,0000

1991 3 2,0000

1991 4 3,0000

1991 4 5,0000 […]

Excerpt from the data set for the second half of Cook's study.

Do you only understand “train station”? Cook et al. declare that the data is anonymized. I quickly discovered the reason for this on the pages of Cook et al. can not find. I leave it to the reader to judge how plausible such anonymization or data protection is.

In the data set you can see the following: The first column shows the publication year of the study, the second column shows the evaluation by Cook et al. and the third column is the self-assessment of the scientists including the decimal places.

Due to the anonymization, it is no longer possible to understand which studies the evaluations refer to in detail. Here you can claim anything and type in any numbers you want, in other words: There are massive opportunities for manipulation in this data set. I don't blame John Cook's team for that. But by amputation of the data, they expose themselves to the accusation that the accuracy of the data set as such can no longer be verified afterwards. So why was data deleted here?

Due to these amputated data columns, all of John Cook and colleagues' efforts and hours of work for the second part are actually invalid. Because of the data that was subsequently deleted and the resulting impossibility of verifying this part of the work, I fundamentally question the willingness of Cook's working group to proceed scientifically.

Methods

Nevertheless, I loaded the data into my spreadsheet program and checked how many of the individual works were assigned to which approval group (or category, as I called it in the last article).

(I will not go into the extent to which Cook et al. incorrectly classified scientific articles according to feedback from individual scientists in the comparison between the second and the first part of the study. I have not yet checked this and this could be done in a later date discuss further articles.)

Result

You can read the sobering result of my little calculations here:

Here you can download the corresponding Open Office table and check my calculations.

Briefly summarized:

The self-assessment of 1189 authors, referring to 2142 studies, produced the following result:

This time, 10.58% of the authors are of the opinion that humans are largely responsible for climate change. (Group 1) But not 97.2%!

25.8% of the authors believe that humans have a share in climate change, but do not state the extent of the share. (Group 2)

And 25.37% of the authors think they have somehow implicitly mentioned that humans are responsible for climate change. (Group 3)

This time 36.42% do not want to commit to the topic, so according to Cook they belong to group 4.

discussion

Again, that doesn't sound like 97.2% as suggested by Cook et al. claimed in the introduction.

If we combine the first three approval groups, we get 61.75% according to our own data.

Compare Table 4 from Cook's work:

This corresponds almost exactly to the 62.7% that Cook reports in his table as agreeing with the anthropogenic global warming (AGW) consensus. I can't explain how the slight difference in the percentage values ​​comes about.

But the attentive reader will already guess. Cook and colleagues have again, against all logic, combined the first three consent groups and simply misleadingly claimed that all of these groups agree on a consensus that humans are responsible for the majority of current climate change.

And finally, they removed group 4 (those who did not make a statement) from the sample size, which ultimately led to the incredible 97.2% consensus.

What I think about it is now well known. My amusement is limited.

Keep in mind that the 1,1944 scientific articles that Cook's group examined were only shortlisted because they were the result of a keyword search for " global warming " or " global climate change ."

Reducing the sample size afterwards and excluding individual articles from the calculations because they did not express a clear position on the topic is not possible here. The articles are already a selection, as only those that deal with the topic of 'climate change' are listed. If scientists don't make a clear statement on the topic, there are reasons for that. This also needs to be documented.

(But even if you exclude the works without expressing an opinion on climate change from the sample, you only get a proportion of 1.59% of works in the first part that agree with the climate consensus that humans play a more than 50% share in climate change. This is the same far from 97%. )

It is simply incredibly astonishing to see how carelessly numbers are handled here. One cannot help but get the impression that this study only serves to provide material for debates with so-called “climate deniers”.

And according to Wikipedian Andol, climate deniers are anyone who is skeptical about even individual parts of the official statements from the IPCC. Andol is the Wikipedian who is only too happy to use Cook's material.

And Andol made 22 of 29 entries for the name “Cook” in the Wikipedia article called “ Denial of man-made global warming ” (which only means the John Cook discussed here). And yes, Andol is almost the sole author of this article with over 88%. (as of January 29, 2020)

See the following statistics:

Apparently Andol has a special affection for John Cook's work. All of this does not serve to inform the reader neutrally, but rather to influence political opinions.

The targeted influence on the formation of opinions in political discourse is neither the task of science nor the task of a lexicon. At most, they should provide neutral data. Not more!

And this alleged 97.2% consensus is graphically presented very beautifully, so that even the most lazy viewer immediately understands that as a skeptic he would clearly be in the minority:

Work that comes to the same disastrous conclusion regarding the Cook study is often classified in a dubious camp. This also happens in the media that I regularly consume, i.e. KenFM, Rubikon, Free21, etc. Other publications that come to a similar conclusion independently of Cook's study are, however, emphasized as important. It is not checked whether similar number manipulations could occur. This is polemic and has no place in factual discussions. There is no discussion of the content of the texts here; instead, the quality of the texts is judged based on the alleged social or scientific reputation of the authors or the environment in which the texts are published. This is not good and is the opposite of encouraging independent thinking.

A flawed Cook study says nothing about the truth of other studies that come to similar results in the same area. One can express an initial suspicion that the remaining studies should be examined more closely, but nothing more.

Conversely, the results of other studies say nothing about the accuracy of the Cook study. As an exception, an analogy: A student who arrives at the assumed correct result in a math test, but has made major errors in many places in the calculation, will hardly receive a significant portion of the raw points to be awarded. It becomes even more problematic if he copied his neighbor's result but didn't realize that he had to write a different version of the math paper.

The impression was given several times in various comments that I had not even mentioned that there were other studies on the topic of “climate consensus”. I refer you to the following paragraph of my first article:

Based on this data, we can ask a much further question:

How is it possible for the other seven known studies on the alleged climate consensus to achieve approval ratings of up to 99%? With 11,944 publications examined, the Cook study already covers a fairly large amount of scientific work and therefore also statements on climate change. If we find only a negligibly small proportion of agreement with the IPCC's alleged climate consensus, then on what data basis do the other studies arrive at 99%? There is an initial initial suspicion that there may be something wrong with these studies too. “Further research has to be done.”

To give the impression that I have not made any reference to other studies is grossly misleading. Or you simply missed this section.

Did John Cook's working group work properly? No she did not! Neither in the first nor in the second part of the study.

I'm curious to see what else we could find out about the non-anonymized data set for the second part, if we could find it somewhere.

Preview of another article on the topic

I received numerous tips and letters about my last article, all of which agreed that the article only scratched the tip of the iceberg and that there were even more inconsistencies hidden.

Prof. Bandelt also sent writings from well-known scientists who massively criticized the Cook study. I have read through these and find these articles to be extremely important contributions to the topic.

At this point I would like to highlight two detailed contributions from

• Richard Tol (one of the leading economists and former employee at the IPCC = “Intergovernmental Panel on Climate Change”)
• Andrew Montford (a chemist and journalist who critically follows numerous climate research processes on his well-known Bishop Hill blog.)

Richard Tol and Andrew Montford make even further allegations about the Cook study. They shed light on very important things that I haven't discussed here. I will examine and summarize these in another article on the topic. In particular, the question of whether the Cook study was carried out with an open mind is examined in more detail by the authors mentioned.

 

Text: Markus Fiedler, February 2020, updated on May 24, 2023