Policy Documents

You Call This Consensus?

Joseph L. Bast –
July 7, 2011

Contrary to what you read repeatedly in daily newspapers or hear on television, most scientists do not believe there is a “scientific consensus” that man-made climate change (often labeled anthropogenic global warming, or AGW) is or will be a catastrophe. Unfortunately, the old/mainstream/dead media will be the last folks to acknowledge this, so people who dispute the “consensus” will continue to be slandered and abused for years to come.

It is important to distinguish between the statement, which is true, that there is no scientific consensus that AGW is or will be a catastrophe, and the also-true claims that the climate is changing (of course it is, it is always changing) and that most scientists believe there may be a human impact on climate (our emissions and alterations of the landscape are surely having an impact, though they are often local or regional (like heat islands) and small relative to natural variation).

The three different statements are not contradictory or mutually exclusive. Yet it is difficult to find a reporter for a major daily newspaper who understands this elementary distinction. Since reporters aren’t all stupid, we can only guess as to their motives for blurring this important distinction.

What evidence is there to support my claim? I believe it follows from a reasonable interpretation of the following evidence.

(1) The latest international survey of climate scientists by German scientists Dennis Bray and Hans von Storch found (quoting my own interpretation of their results) that “for two-thirds of the questions asked, scientific opinion is DEEPLY DIVIDED, and in half of those cases, most scientists DISAGREE with positions that are at the foundation of the alarmist case.” If you don’t believe that climate models are good enough to predict future climate conditions, for example, how can you “believe” man-made global warming will be a threat?

Unfortunately, the survey shows that disagreement and outright skepticism about the underlying science of AGW doesn’t prevent most scientists from expressing their belief that man-made global warming is a serious problem. This is the nature of a popular delusion, whereby bright people believe dumb things simply because other people believe it.

Bray and Storch are very coy in reporting and admitting the amount of disagreement their surveys find on the basic science of global warming. In an early essay in 1999, reporting on the results of their first survey, they remark on how a willingness to make predictions and recommendations about public policy that aren’t supported by actual science is a sign of “post normal science,” or the willingness to rely on “consensus” rather than actual scientific knowledge when the risks are perceived as being great. This is little different from what I have been calling the “global warming delusion.”

(2) I found pretty much the same thing in an analysis I did of Bray and von Storch’s 2003 survey. That survey found that only 9.4 percent “strongly agreed” and 25.3 percent “agreed” with the statement “climate change is mostly the result of anthropogenic causes.” Some 10.2 percent “strongly disagreed.” Fewer than half the scientists surveyed agreed that “natural scientists have established enough physical evidence to turn the issue of global climate change over to social scientists for matters of policy discussion.” Only 18.6 percent said they believed global warming skeptics receive “too much coverage.”

(3) A 2010 survey of meteorologists found that 63 percent believe global warming is caused mostly by natural causes, and only 31 percent believe humans are primarily responsible.

(4) Another 2010 survey of meteorologists, this one published in the Bulletin of the American Meteorological Society, found only one in four American Meteorological Society broadcast meteorologists agrees with United Nations’ claims that humans are primarily responsible for recent global warming.

(5) The often-mocked but never refuted Petition Project” has, since 2007, been signed by more than 31,072 American scientists, including 9,021 with Ph.D.s. The petition says, in part, “There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.” There is no comparable survey attesting to a widespread embrace of the alarmist position.

(6) A 2006 survey of scientists in the U.S. by the National Registry of Environmental Professionals found 41 percent disagreed that the planet’s recent warmth “can be, in large part, attributed to human activity,” and 71 percent disagreed that recent hurricane activity is significantly attributable to human activity. This is, admittedly, less than “most,” but it preceded the disclosures of Climategate, IPCC-gate, and five years of global cooling.

(7) The results of a less scientific survey were announced on the Web site of Scientific American, itself a publication with a highly biased coverage of environmental issues. Only 26 percent of readers of Scientific American responded to the magazine’s online poll saying they believe human emissions are causing global warming.

(8) Even Phil Jones, a prominent alarmist and central figure in the Climategate scandal, doesn’t believe there is a scientific consensus or that recent temperature trends are unusual. In an interview published by BBC News, Phil Jones was asked, “When scientists say ‘the debate on climate change is over’, what exactly do they mean -- and what don’t they mean?” Jones responded, “I don’t believe the vast majority of climate scientists think this. This is not my view.”

Jones also acknowledged that recent warming (beginning in 1975 after three decades of cooling global temperatures) is not unprecedented, and is similar to warming periods that occurred from 1860 – 1880 and from 1910 – 1940. Asked about the global temperature trend since 1995, Jones asserted there is no statistically significant warming since 1995. Asked about the global temperature trend since 2002, Jones acknowledged global cooling, but said it is not statistically significant.

(9) One searches in vain for contrary data in support of a “scientific consensus” or the catastrophic forecasts. It certainly can’t be found in Naomi Oreskes imaginative counting of journal articles that appeared, in the non-peer reviewed letters section of Nature in 2004. A no-less rigorous study by Benny Peiser that attempted to replicate her results searched the abstracts of 1,117 scientific journal articles on “global climate change” found only 13 (1 percent) explicitly endorse the “consensus view” while 34 reject or cast doubt on the view that human activity has been the main driver of warming over the past 50 years. According to Peiser: “My analysis also shows that there are almost three times as many abstracts that are sceptical of the notion of anthropogenic climate change than those that explicitly endorse it.”

(10) A few years later, in 2008, Environment & Energy published research by medical researcher Dr. Klaus-Martin Schulte, who used the same database and search terms as Oreskes to examine papers published from 2004 to February 2007. (Note that DeSmogBlog reported in 2007 that E&E rejected the study and apparently never corrected its error.) According to the publication’s abstract:

The state of the scientific consensus about climate change was studied by a review of the 539 papers on “global climate change” found on the Web of Science database from January 2004 to mid-February 2007, updating research by Oreskes, who had reported that between 1993 and 2003 none of 928 scientific papers on “global climate change” had rejected the consensus that more than half of the warming of the past 50 years was likely to have been anthropogenic. In the present review, 31 papers (6 percent of the sample) explicitly or implicitly reject the consensus. Though Oreskes said that 75 percent of the papers in her former sample endorsed the consensus, fewer than half now endorse it. Only 7 percent do so explicitly. Only one paper refers to “catastrophic” climate change, but without offering evidence. There appears to be little evidence in the learned journals to justify the climate-change alarm that now harms patients.

(See also this link from Daily Tech titled, Survey: Less Than Half of all Published Scientists Endorse Global Warming Theory.”)

(11) What of the claim that “all” of the scientific bodies of the world endorse alarmism? Leaders of these groups are typically more political than scientific and they can be depended on to voice the current politically correct views on issues that attract government funding. They also do not poll their members before issuing statements. Even with all this in mind, it’s notable that the Polish Academy of Sciences does not endorse the “consensus” claims.

Britain’s Royal Society, France’s National Academy of Sciences, and India’s National Action Plan on Climate Change have all recently expressed skepticism or embraced important parts of the skeptics’ position.

The leaders of the world’s national science academies are expressing the same “cognitive dissonance” as the individual scientists that Bray and von Storch’s surveyed: they say they “believe” in AGW and fear its consequences, but they are skeptical of the scientific claims that must be true to support that belief. The Amsterdam-based InterAcademy Council (IAC), which is made up of the presidents of many of the world’s national science academies, conducted an audit of the IPCC in 2010. It found that the IPCC doesn’t properly peer review its reports, the selection of scientists who participate is politicized, the summary for policymakers is the product of negotiation among governments and is not written by scientists, and more. IAC recommends structural reforms to fix IPCC’s flaws before IPCC’s next report, due in 2014.

So the public declarations of national science academies may reflect the broader opinions and fears of politicians and scientists, but it is not an endorsement of the underlying science, and cannot be construed as evidence that the science is sound. The leaders of those very organizations have stated publicly that they do not believe the science is sound.

(12) What of the claim that the “3,000 scientists” who participated in production of the IPCC’s 2007 report believe in AGW? The IAC report described in (11) demolishes the credibility of that body, validating what climate realists have been saying for years. The IPCC is a political body, not a scientific body, and its reports are political documents. But just as important, the number refers to the number of scientists and environmental activists who participated in any way in the IPCC, often as reviewers of a single section of a single chapter. They cannot be assumed to endorse the reports’ conclusions because they were never asked. In public comments, many reviewers say they do not, in fact, endorse the IPCC’s conclusions. Very few scientists helped write or review Chapter 9, which addressed the critical issue of attribution – what causes climate change. John McLean found that only 60 scientists help write or commented favorably on that chapter during peer review.

So when someone says the IPCC reports are proof of a scientific consensus on AGW, you should say “the IPCC is proof that 60 scientists believe in AGW, no more and no less than that.”

(13) What of the claim that “97% of climate scientists believe in AGW”? The origin of this spurious claim is a 2009 online survey of scientists by two University of Illinois professors who claimed to have found that 75 out of 77 climate scientists (yes, only 77 climate scientists!) answered yes to this question: “Do you think human activity is a significant contributing factor in changing mean global temperatures?” The sample size is bizarrely small – more about that in a moment -- and the question itself is meaningless. Most “skeptics” believe “human activity” – which includes everything from clearing forests to make way for crops to the urban heat islands created by cities – is having some impact on global temperatures. This survey tells us nothing about the real issue about which AGW advocates claim a consensus, that human emissions of greenhouse gases are causing catastrophic climate change.

Regarding the sample size … according to Lawrence Solomon, the two researchers who produced the survey deliberately left out solar scientists, space scientists, cosmologists, physicists, meteorologists, and astronomers … all scientists likely to be aware of natural causes of climate change. Only scientists employed by governments or universities were chosen to be surveyed, introducing another source of bias. Of the 10,000 or so scientists left, about 3,000 replied to the 2-minute online survey. No surprise, 82% of that unrepresentative sample answered yes to the ambiguous question. The authors then looked at a subset of just 77 scientists who participated in the survey and were successful in getting more than half their papers accepted by peer-reviewed climate science journals and found that 75 of those answered “yes.” 75/77 = 97%.

This may be how sausage is made, but it is not how accurate surveys are conducted. The “97% of climate scientists” claim is garbage. Anyone who cites it ought to be ashamed.


Joseph Bast is president and CEO of The Heartland Institute.