The Bogus ‘Consensus’ Argument on Climate Change

Written by Robert P. Murphy

Climate deniers don’t deserve to be called “skeptics ...

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One of the popular rhetorical moves in the climate change debate is for advocates of aggressive government intervention to claim that “97% of scientists” agree with their position, and so therefore any critics must be unscientific “deniers.”

Now these claims have been dubious from the start; people like David Friedman have demonstrated that the “97% consensus” assertion became a talking point only through a biased procedure that mischaracterized how journal articles were rated, and thereby inflating the estimate.

But beyond that, a review in The New Republic of a book critical of mainstream economics uses the exact same degree of consensus in order to cast aspersions on the science of economics. In other words, when it comes to the nearly unanimous rejection of rent control or tariffs among professional economists, at least some progressive leftists conclude that there must be group-think involved.

The one consistent thread in both cases—that of the climate scientists and that of the economists—is that The New Republic takes the side that will expand the scope of government power, a central tenet since its birth by Herbert Croly a century ago.

The Dubious “97% Consensus” Claim Regarding Climate Science

Back in 2014, David Friedman worked through the original paper that kicked off the “97% consensus” talking point. What the original authors, Cook et al., actually found in their 2013 paper was that 97.1% of the relevant articles agreed that humans contribute to global warming. But notice that that is not at all the same thing as saying that humans are the main contributors to observed global warming (since the Industrial Revolution).

This is a huge distinction. For example, I co-authored a Cato study with climate scientists Pat Michaels and Chip Knappenberger, in which we strongly opposed a U.S. carbon tax. Yet both Michaels and Knappenberger would be climate scientists who were part of the “97% consensus” according to Cook et al. That is, Michaels and Knappenberger both agree that, other things equal, human activity that emits carbon dioxide will make the world warmer than it otherwise would be. That observation by itself does not mean there is a crisis nor does it justify a large carbon tax.

Incidentally, when it comes down to what Cook et al. actually found, economist David R. Henderson noticed that it was even less impressive than what Friedman had reported. Here’s Henderson:

[Cook et al.] got their 97 percent by considering only those abstracts that expressed a position on anthropogenic global warming (AGW). I find it interesting that 2/3 of the abstracts did not take a position. So, taking into account David Friedman’s criticism above, and mine, Cook and Bedford, in summarizing their findings, should have said, “Of the approximately one-third of climate scientists writing on global warming who stated a position on the role of humans, 97% thought humans contribute somewhat to global warming.” That doesn’t quite have the same ring, does it? [David R. Henderson, bold added.]

So to sum up: The casual statements in the corporate media and in online arguments would lead the average person to believe that 97% of scientists who have published on climate change think that humans are the main drivers of global warming. And yet, at least if we review the original Cook et al. (2013) paper that kicked off the talking point, what they actually found was that of the sampled papers on climate change, only one-third of them expressed a view about its causes, and then of that subset, 97% agreed that humans were at least one cause of climate change. This would be truth-in-advertising, something foreign in the political discussion to which all AGW issues now seem to descend.

The New Republic’s Differing Attitudes Towards Consensus

The journal The New Republic was founded in 1914. Its website states: “For over 100 years, we have championed progressive ideas and challenged popular opinion….The New Republic promotes novel solutions for today’s most critical issues.”

With that context, it’s not surprising that The New Republic uses the alleged 97% consensus in climate science the way other progressive outlets typically do. Here’s an excerpt from a 2015 article (by Rebecca Leber) in which Republicans were excoriated for their anti-science stance on climate change:

Two years ago, a group of international researchers led by University of Queensland’s John Cook surveyed 12,000 abstracts of peer-reviewed papers on climate change since the 1990s. Out of the 4,000 papers that took a position one way or another on the causes of global warming, 97 percent of them were in agreement: Humans are the primary cause. By putting a number on the scientific consensus, the study provided everyone from President Barack Obama to comedian John Oliver with a tidy talking point. [Leber, bold added.]

Notice already that Leber is helping to perpetuate a falsehood, though she can be forgiven—part of David Friedman’s blog post was to show that Cook himself was responsible (Friedman calls it an outright lie) for the confusion regarding what he and his co-authors actually found. And notice that Leber confirms what I have claimed in this post, namely that it was the Cook et al. (2013) paper that originally provided the “talking point” (her term) about so-called consensus.

The point of Leber’s essay is to then denounce Ted Cruz and certain other Republicans for ignoring this consensus among climate scientists:

All this debate over one statistic might seem silly, but it’s important that Americans understand there is overwhelming agreement about human-caused global warming. Deniers have managed to undermine how the public views climate science, which in turn makes voters less likely to support climate action.

Now here’s what’s really interesting. A colleague sent me a recent review in The New Republic of a new book by Binyan Appelbaum that is critical of the economics profession. The reviewer, Robin Kaiser-Schatzlein, quoted with approval Appelbaum’s low view of consensus in economics:

Appelbaum shows the strangely high degree of consensus in the field of economics, including a 1979 survey of economists that “found 98 percent opposed rent controls, 97 percent opposed tariffs, 95 percent favored floating exchange rates, and 90 percent opposed minimum wage laws.” And in a moment of impish humor he notes that “Although nature tends toward entropy, they shared a confidence that economies tend toward equilibrium.” Economists shared a creepy lack of doubt about how the world worked. [Kaiser-Schatzlein, bold added.]

Isn’t that amazing? Rather than hunting down and demonizing Democratic politicians who dare to oppose the expert consensus on items like rent control—which Bernie Sanders has recently promoted—the reaction here is to guffaw at the hubris and “creepy lack of doubt about how the world [works].”


From the beginning, the “97% consensus” claim about climate change has been dubious, with supporters claiming that it represented much more than it really did. Furthermore, a recent book review in The New Republic shows that when it comes to economic science, 97% consensus means nothing, if it doesn’t support progressive politics.

Originally published at the Institute for Energy Research

Robert P. Murphy is a Senior Fellow with the Mises Institute. He is the author of many books. His latest is Contra Krugman: Smashing the Errors of America’s Most Famous Keynesian. His other works include Chaos Theory, Lessons for the Young Economist, and Choice: Cooperation, Enterprise, and Human Action (Independent Institute, 2015) which is a modern distillation of the essentials of Mises’s thought for the layperson. Murphy is co-host, with Tom Woods, of the popular podcast Contra Krugman, which is a weekly refutation of Paul Krugman’s New York Times column. He is also host of The Bob Murphy Show.



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Comments (7)

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    Back in 2014, David Friedman worked through the original paper that kicked off the “97% consensus” talking point.


    The original survey that kicked off the “97% consensus” was not the paper created by Cook (self described cartoonist) et al, it was in fact:

    An opinion survey of earth scientists on global climate change was conducted by Margaret R K Zimmerman, MS, and published by the University of Illinois in 2008.

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    T. C. Clark


    The latest survey is 11,000 scientists worldwide declare that there is a climate emergency. Are you scared yet? Among the scientists is the famous “Mickey Mouse”. Who is a “scientist”? Is a scientist a person who has published at least one paper in a scientific journal that was peer reviewed? The 11,000 include no doubt many other Mickey Mouse jokers and many from other sciences than climate. There was a poll done a few years ago by sending out a one page question survey (self addressed stamped envelope included) to scientists that asked if they were concerned about global warming…..the majority answered that they were not worried about any global warming. Polls and surveys are not the answer. I fight the battle against the man made CO2 global warming group because I believe it is not true and not only will cost the world in the future, but is costing a great deal now. I do not benefit monetarily and in fact it costs me money and time to fight this wasteful but necessary war.

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      Ezra Levant of Rebel Media in Canada checked out the 11,000 “scientists” survey and discovered that it is a 4-page op-ed (published as “Viewpoint”) that garnered signatories by simple button clicks.

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    Andy Rowlands


    The so-called ‘97% consensus’ has been thoroughly debunked by any number of eminently qualified persons, yet the alarmists still cling to it and throw it at skeptics as indisputable ‘proof’ at every available opportunity.

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    The 97% of scientists agree claim is bunk and they know it but they use it because most of the public is not aware of where it came from and think it has to be true. They also like to toss out the “consensus science/scientific consensus” term. Consensus science is by definition a mutual agreement to believe something or treat something as fact in the absence of any real (experimental or empirical) evidence. This is also the basis of religions. The latest “11,000 scientists declaration” clickers were mostly consensus science types. They not only believe in the mantra, they also believe they are scientists. The tragedy is that the main stream media are too dumb or too biased (or both) to report this event with critical evaluation (well except Rebel Media).

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    The actual results of the Cook survey (undertaken by subscribers to his fatuous blog):

    Response No of extracts % of total

    Yes, more than 50% of the warming 65 0.54%
    Contributes to warming, but don’t know how much 3,831 32.07%
    Uncertain 40 0.33%
    No 78 0.66%
    No opinion either way 7,930 66.40%

    Total 11,944 100%

    See how he got his 97% figure? Yep, he just ignored the 7,930 papers that had no position either way. The 3,896 that ‘endorse’ the position amounts to 97% only when the ‘no opinion either way’ 7,930 are taken out. This is a flagrant abuse of the proper method of compiling statistics.

    The true figure of those that endorse the position – either explicitly or implicitly – 3,896 actually amounts to only 32.6% of the total number of papers, just under one in three. And those who believe that CO2 is dangerous by causing more than half the warming of the world comprise a measly half of one percent.

    Cook was not the only one to come up with the 97% figure.

    The United States Academy of Science surveyed the papers of 1,372 climate researchers actively publishing in journals. They found that 97% agreed with the IPCC line. Since sceptical (realist) scientists find it almost impossible to have their work published, this is hardly surprising.

    A paper published in the journal of the American Geophysical Union entitled ‘Examining the Scientific Consensus on Climate Change’ was the result of an on-line poll of climate scientists. A mere 79 scientists responded. Surprise, surprise, 75 of them (97.9%) agreed with the IPCC.

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