By Paul MacRae

A while ago, I received an email from a friend who asked:

How can many, many respected, competitive, independent science folks be so wrong about [global warming] (if your [skeptical] premise is correct). I don’t think it could be a conspiracy, or incompetence. …  Has there ever been another case when so many ‘leading’ scientific minds got it so wrong?

The answer to the second part of my friend’s question—“Has there ever been another case where so many ‘leading’ scientific minds got it so wrong?”—is easy. Yes, there are many such cases, both within and outside climate science. In fact, the graveyard of science is littered with the bones of theories that were once thought “certain” (e.g., that the continents can’t “drift,” that Newton’s laws were immutable, and hundreds if not thousands of others). Science progresses by the overturning of theories once thought “certain.”

And so, Carl Sagan has written: “Even a succession of professional scientists—including famous astronomers who had made other discoveries that are confirmed and now justly celebrated—can make serious, even profound errors in pattern recognition.”[1] There is no reason to believe that climate scientists (alarmist or skeptic) are exempt from this possibility.

That leaves the first question, which is how so many “respected, competitive, independent science folks [could] be so wrong” about the causes and dangers of global warming, assuming they are wrong. And here, I confess that after five years of research into climate fears, this question still baffles me.

 Climate certainty is baffling

It is not baffling that so many scientists believe humanity might be to blame for global warming. If carbon dioxide causes warming, additional CO2 should produce additional warming. But it’s baffling that alarmist climate scientists are so certain that additional carbon dioxide will produce a climate disaster, even though there is little empirical evidence to support this view, and much evidence against it, including a decade of non-warming. This dogmatism makes it clear, at least to those outside the alarmist climate paradigm, that something is very wrong with the state of “consensus” climate science.

There are many possible reasons for this scientific blindness, including sheer financial and career self-interest: scientists who don’t accept the alarmist paradigm will lose research grants and career doors will be closed to them. But one psychological diagnosis fits alarmist climate science like a glove: groupthink. With groupthink, we get the best explanation of “how can many, many respected, competitive, independent science folks be so wrong.”

Groupthink was extensively studied by Yale psychologist Irving L. Janis and described in his 1982 book Groupthink: Psychological Studies of Policy Decisions and Fiascoes. Janis was curious about how teams of highly intelligent and motivated people—the “best and the brightest” as David Halberstam called them in his 1972 book of the same name—could have come up with political policy disasters like the Vietnam War, Watergate, Pearl Harbor and the Bay of Pigs. Similarly, in 2008 and 2009, we saw the best and brightest in the world’s financial sphere crash thanks to some incredibly stupid decisions, such as allowing sub-prime mortgages to people on the verge of bankruptcy.

In other words, Janis studied why and how groups of highly intelligent professional bureaucrats and, yes, even scientists, screw up, sometimes disastrously and almost always unnecessarily. The reason, Janis believed, was “groupthink.” He quotes Nietzsche’s observation that “madness is the exception in individuals but the rule in groups,” and notes that groupthink occurs when “subtle constraints … prevent a [group] member from fully exercising his critical powers and from openly expressing doubts when most others in the group appear to have reached a consensus.”[2]

Janis found that even if the group leader expresses an openness to new ideas, group members value consensus more than critical thinking; groups are thus led astray by excessive “concurrence-seeking behavior.”[3] Therefore, Janis wrote, groupthink is “a model of thinking that people engage in when they are deeply involved in a cohesive in-group, when the members’ strivings for unanimity override their motivation to realistically appraise alternative courses of action.”[4]

 The groupthink syndrome

The result is what Janis calls “the groupthink syndrome.” This consists of three main categories of symptoms:

  1. Overestimate of the group’s power and morality, including “an unquestioned belief in the group’s inherent morality, inclining the members to ignore the ethical or moral consequences of their actions.” [emphasis added]
  2. Closed-mindedness, including a refusal to consider alternative explanations and stereotyped negative views of those who aren’t part of the group’s consensus. The group takes on a “win-lose fighting stance” toward alternative views.[5]
  3. Pressure toward uniformity, including “a shared illusion of unanimity concerning judgments conforming to the majority view”; “direct pressure on any member who expresses strong arguments against any of the group’s stereotypes”; and “the emergence of self-appointed mind-guards … who protect the group from adverse information that might shatter their shared complacency about the effectiveness and morality of their decisions.”[6] [emphasis added]

It’s obvious that alarmist climate science—as explicitly and extensively revealed in the Climatic Research Unit’s “Climategate” emails—shares all of these defects of groupthink, including a huge emphasis on maintaining consensus, a sense that because they are saving the world, alarmist climate scientists are beyond the normal moral constraints of scientific honesty (“overestimation of the group’s power and morality”), and vilification of those (“deniers”) who don’t share the consensus.

For example, regarding Symptom 1, overestimation of the group’s power and morality: leading consensus climate spokespeople like Al Gore, James Hansen, and Stephen Schneider have stated outright that they feel it’s acceptable and even moral to exaggerate global-warming claims to gain public support, even if they have to violate the broader scientific principle of adherence to truth at all costs. (See for examples.) Consensus climate science also overestimates the power of humanity to override climate change, whether human-caused or natural, just as government planners overestimated the U.S.’s ability to win the Vietnam War.

Regarding Symptom 2, closed-mindedness, there are many cases of the alarmist climate paradigm ignoring or suppressing evidence that challenges the AGW hypothesis. The Climategate emails, for example, discuss refusing publication to known skeptics and even firing an editor favorable to skeptics.

Regarding Symptom 3, pressure toward uniformity: within alarmist climate science there is a “shared illusion of unanimity” (i.e., a belief in total consensus) about the majority view when this total or near-total consensus has no basis in reality. For example, the Oregon Petition against the anthropogenic warming theory has 31,000 signatories, over 9,000 of them with PhDs.

Climate scientists who dare to deviate from the consensus are censured as “deniers”—a choice of terminology that can only be described as odious. And the Intergovernmental Panel on Climate Change explicitly aims for “consensus” in its reports—it does not publish minority reports, and yet it is impossible that its alleged more than “2,000 scientists” could completely agree on a subject as complicated as climate.

 Group polarization

Janis notes one other form of dysfunctional group dynamic that arises out of groupthink and that, in turn, helps create even more groupthink:

The tendency for the collective judgments arising out of group discussions to become polarized, sometimes shifting toward extreme conservatism and sometimes toward riskier forms of action than the individual members would otherwise be prepared to take.[7] [emphasis added]

This dynamic is commonly referred to as “group polarization.” As a process, “when like-minded people find themselves speaking only with one another, they get into a cycle of ideological reinforcement where they end up endorsing positions far more extreme than the ones they started with.”[8] [emphasis added] And because these positions are so extreme, they are held with extreme ferocity against all criticisms.

Examples of climate alarmist groupthink

Groupthink is common in academic disciplines. For example, philosopher Walter Kaufmann, a world-renowned editor of Nietzsche’s works, identifies groupthink in his discipline as follows:

There is a deep reluctance to stick out one’s neck: there is safety in numbers, in belonging to a group, in employing a common method, and in not developing a position of one’s own that would bring one into open conflict with more people than would be likely to be pleased.[9]

Similarly, in the 2009 Climategate emails, CRU director Phil Jones shows this “deep reluctance to stick out one’s neck” in writing (July 5, 2005): “The scientific community would come down on me in no uncertain terms if I said the world had cooled from 1998.”

Keith Briffa laments (Sept. 22, 1999): “I know there is pressure to present a nice tidy story as regards ‘apparent unprecedented warming in a thousand years or more in the temperature proxy data’ but in reality the situation is not quite so simple. … I believe that the recent warmth was probably matched about 1,000 years ago.” [emphasis added]

Elsewhere, Briffa notes (April 29, 2007): “I tried hard to balance the needs of the science and the IPCC, which were not always the same. I worried that you might think I gave the impression of not supporting you well enough while trying to report on the issues and uncertainties.” [emphasis added]

All of the above (there are many more examples in the Climategate emails) reveal scientific groupthink, which puts the needs and desires of a peer group—the desire for “consensus”—ahead of the scientific facts. We would, undoubtedly, find other examples of alarmist groupthink if we could examine the emails of other promoters of climate alarmism, like James Hansen’s Goddard Institute.

This groupthink isn’t at all surprising. After all, alarmist climate scientists attend several conferences a year with like-minded people (the views of outright “deniers” are not welcome, as the CRU emails clearly reveal). In the absence of real debate or dissent they easily persuade themselves that human beings are the main reason the planet is warming and it’s going to be a catastrophe. Why? Because everyone else seems to think so and, in groupthink, consensus is highly valued. The same principle operates strongly, of course, in religion, in politics—indeed, in almost all human social activities.

 The ‘hockey stick’ and groupthink

Climate alarmists will, of course, angrily dispute that climate science groupthink is as strong as claimed here. However, groupthink is clearly identified in the 2006 Wegman report into the Michael Mann hockey stick controversy. The Wegman report was commissioned by the U.S. House Science Committee after Mann refused to release all the data leading to the hockey stick conclusions, conclusions that eliminated the Medieval Warm Period and Little Ice Age in order to show today’s warming as unprecedented. In fact, as mathematician Steve McIntyre discovered after years of FOI requests, the calculations in Mann’s paper had not been checked by the paper’s peer reviewers and were, in fact, wrong.

Mann 'hockey stick'

The National Academy of Sciences committee, led by Dr. Edward Wegman, an expert on statistics, identified one of the reasons why Mann’s paper was so sloppily peer-reviewed as follows:

There is a tightly knit group of individuals who passionately believe in their thesis. However, our perception is that this group has a self-reinforcing feedback mechanism and, moreover, the work has been sufficiently politicized that they can hardly reassess their public positions without losing credibility.[10] [emphasis added]

Wegman noted that the Mann paper became prominent because it “fit some policy agendas.”[11] The Wegman Report also observed:

As statisticians, we were struck by the isolation of communities such as the paleoclimate community that rely heavily on statistical methods, yet do not seem to be interacting with the mainstream statistical community. The public policy implications of this debate are financially staggering and yet apparently no independent statistical expertise was sought or used.[12] [emphasis added]

In other words, alarmist climate scientists are part of an exclusive group that talks mainly with itself and avoids groups that don’t share the anthropogenic global warming hypothesis and alarmist political agenda. Overall, Wegman is describing with great precision a science community whose conclusions have been distorted and polarized by groupthink.

 Recognizing groupthink

After the Climategate emails, some consensus climate scientists began to recognize the dangers of groupthink within their discipline. So, Georgia Tech climatologist Judith Curry wrote in 2009:

 In my opinion, there are two broader issues raised by these emails that are impeding the public credibility of climate research: lack of transparency in climate data, and “tribalism” in some segments of the climate research community that is impeding peer review and the assessment process.[13]

Similarly, IPCC contributor Mike Hulme wrote:

 It is possible that climate science has become too partisan, too centralized. The tribalism that some of the leaked emails display is something more usually associated with social organization within primitive cultures; it is not attractive when we find it at work inside science.[14] [emphasis added]

In short, it is clear that groupthink—a later, more scientific word for “tribalism”—is strongly at work within alarmist climate science, however much the affected scientists refuse to recognize it. As a result of tribalism (groupthink), alarmist climate science makes assertions that are often extreme (polarized), including the explicit or implicit endorsement of claims that global warming will lead to “oblivion,” “thermageddon,” mass extinctions, and the like. Indeed, one of the ironies of climate science is that extremist AGW believers like Gore, Hansen and Schneider have succeeded in persuading the media and public that those who don’t make grandiose claims, the skeptics, are the extremists.

Group polarization offers a rational explanation for extreme alarmist claims, given that the empirical scientific evidence is simply not strong enough to merit such confidence. It is likely that even intelligent, highly educated scientists have been caught in what has been called the “madness of crowds.” Indeed, writing in the Times Higher Education magazine, British philosopher Martin Cohen makes this connection explicit:

Is belief in global-warming science another example of the “madness of crowds”? That strange but powerful social phenomenon, first described by Charles Mackay in 1841, turns a widely shared prejudice into an irresistible “authority”. Could it [belief in human-caused, catastrophic global warming] indeed represent the final triumph of irrationality?[16]

There is strong psychological evidence that alarmist fears of climate change are far more the result of groupthink and the group polarization process than scientific evidence and, yes, this alarmist groupthink has indeed led to the triumph of irrationality over reason.


  1. Carl Sagan, The Demon-Haunted World: Science as a Candle in the Dark. New York: Ballantine Books, 1996, p. 49.
  2. Irvin L. Janis, Groupthink: Psychological Studies of Policy Decisions and Fiascoes. Boston: Houghton Mifflin, 1982, p. 3.
  3. Janis, p. vii.
  4. Janis, p. 9.
  5. Janis, p. 247.
  6. Janis, pp. 174-175.
  7. Janis, p. 5.
  8. Andrew Potter, “The newspaper is dying—hooray for democracy.” Maclean’s, April 7, 2008, p. 17.
  9. Walter Kaufmann, Critique of Religion and Philosophy. Princeton, NJ: Princeton Univ. Press, 1990 (1958), p. 51.
  10. Edward Wegman, et al., “Ad Hoc Committee Report on the ‘Hockey Stick’ Global Climate Reconstruction.” U.S. House Committee on Energy and Commerce, 2006, p. 65.
  11. Wegman, et al., p. 29.
  12. Wegman, et al., p. 51.
  13. Judith Curry, “On the credibility of climate research.” Climate Audit blog, Nov. 22, 2009.
  14. Andrew Revkin, “A climate scientist who engages skeptics.” Dot.Earth, Nov. 27, 2009.
  15. Steve Fuller, Kuhn vs. Popper: The Struggle for the Soul of Science. Cambridge: Icon Books, 2006 (2003), p. 105.
  16. Martin Cohen, “Beyond debate?” Times Higher Education, Dec. 10, 2009.