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Global Warming Consensus?

We are often told that there is a consensus that global warming is real and human caused. Because of this, a group of global warming skeptics put together a petition to sign that indicates there is a consensus that the evidence is weak or nonexistent for anthropogenic global warming. So, here we have competing consensus claims on the same issue. What is a skeptic to think? To find out, read on…

photo of Earth in a water droplet

Misleading by Petition
Just What is the Consensus on Global Warming?

by Gary J. Whittenberger Ph.D.

Is global warming a real phenomenon, and if so, are humans causing or contributing to it by burning fossil fuels and will it lead to an increased frequency and/or severity of natural disasters? The American public looks to science or scientists to help answer these questions. A petition circulated by a small group of scientists is creating quite a stir, arousing considerable praise and disdain from groups on different sides of the global warming issue.

The petition drive was begun by Dr. Frederick Seitz, now deceased, and is now led by Dr. Arthur Robinson and his son, Dr. Noah Robinson, both members of the Oregon Institute of Science and Medicine (OISM), who remain the chief organizers and expositors of the petition project. Seitz was a physicist and past president of both the National Academy of Sciences and Rockefeller University. The two Robinsons are both chemists and Arthur Robinson is the current director of OISM. According to the website which reports the details of the petition and is presumably authored by Arthur Robinson, “the purpose of the Petition Project is to demonstrate that the claim of “settled science” and an overwhelming “consensus” in favor of the hypothesis of humancaused global warming and consequent climatological damage is wrong.”1 Robinson asserts not just that his collection of 31,072 signatures on a petition has refuted the claim of “settled science” and “overwhelming consensus” among scientists with regard to global warming, but that “The very large number of petition signers demonstrates that, if there is a consensus among American scientists, it is in opposition to the humancaused global warming hypothesis rather than in favor of it.”2 Not only has Robinson failed to substantiate either of his assertions, he is misleading the American public by implying that his petition fairly represents relevant expert opinion.

To understand the problems with Robinson’s “Global Warming Petition Project”, we must first examine how the petition itself was distributed and how signatures were collected. To a sample of persons on the mailing list of American Men and Women of Science,3 Robinson sent a petition packet consisting of a petition card, a return envelope, a cover letter from Seitz, and a 12-page review of the literature on the human-caused global warming hypothesis authored by the two Robinsons and Willie Soon.4 The two main assertions stated on the petition card were that there is no convincing scientific evidence that the human release of carbon dioxide and other gases is causing harmful atmospheric heating and climate change and that the U.S. government should reject the Kyoto Agreement and any other similar proposals. Arthur Robinson not only requested that recipients return the signed petition card, if they agreed with its assertions, but also arranged for the recipients to distribute petition packets to their colleagues. He also enabled other persons to obtain petition packets by simply requesting them through his website, and this procedure ultimately produced five percent of the returned petition cards. Thus, signed petitions were solicited in three different ways.

Although the website for the petition indicates that checks of credentials and identity were performed for signatories of the returned petitions, and invalid petitions were excluded, how the checks were performed is not described. Signed petition cards were accepted only if they came from persons who had “obtained formal educational degrees at the level of Bachelor of Science or higher in appropriate scientific fields”.5 In the end, “valid” and signed petition cards were obtained from 31,072 persons with degrees in the following fields: Earth science (3,697 persons or 12% of the total); computer science and mathematics (903 or 3%); physics and aerospace sciences (5,691 or 18%); chemistry (4,796 or 15%); biology and agriculture (2,924 or 9%); medicine (3,069 or 10%); and engineering and general science (9,992 or 32%). The breakdown according to educational level was: PhD (9,021 or 29%); MS (6,961 or 22%); MD and DVM (2,240 or 7%); and BS or equivalent (12,850 or 41%).5 On his website Robinson fails to report the cross-tabulations of fields of expertise and levels of education for his petition respondents. For example, we aren’t told what percentage of the persons with Earth science expertise had Ph.D. degrees.

Although in one interview Robinson called his petition project a “survey”6, it is definitely not a survey, and because it is not a well-designed scientific survey of the views of a group of relevant experts, its results cannot be used to reach the conclusions about “consensus” that are asserted and hoped for by Robinson. In the first place, Robinson presents neither a dictionary nor an operational definition of “consensus”. He wants to reach conclusions about a consensus, but he spends no time telling us what he thinks a consensus is. According to Merriam-Webster’s Eleventh Collegiate Dictionary, a “consensus” may refer to general agreement, unanimity, judgment by most of those concerned, or group solidarity. Of course if we use the “unanimity” definition of “consensus”, then Robinson’s Global Warming Petition Project shows that a consensus of persons with science degrees, even those with relevant degrees, does not support the hypothesis of human-caused global warming. But this is a trivial conclusion; we knew this before the petition drive! The “unanimity” definition of “consensus”, however, is not the one in which the American public is interested.

If Robinson had been conducting a true survey, he would have offered an operational definition of “consensus” before he started his inquiry. Robinson misleads the public to think that a consensus is defined by some large absolute number of persons. It is not. It is determined by a large percentage of persons in a relevant sample. Does Robinson, or the general public, think of a consensus as agreement within a given group at a level of 75%, 90%, or some other percentage? He does not tell us. He reports only the number of persons who sent back signed petition cards, but he reports neither the total number of persons to whom he sent petition cards in the first place nor the number of persons to whom he sent petition cards who subsequently returned only messages of disagreement. Since Robinson chose to conduct a petition project rather than a well-designed scientific survey, he cannot reach valid conclusions about any consensus, and he should not have attempted to do so.

Had Robinson been interested in finding out the truth about the views of relevant scientists rather than pursuing his own political agenda, he would have given a great deal more consideration to sample selection. Who is a relevant scientific expert when it comes to evaluating the human-caused global warning hypothesis? Robinson seems to have very lenient inclusion criteria. He even seems to think that persons with Bachelors degrees in mathematics and engineering are relevant and qualified experts on the issue. This seems to make about as much sense as considering electricians to be experts on plumbing because they have certificates from trade school just as plumbers do.

In a recent e-mail communication with an acquaintance of mine in which he defended his broad inclusion criteria, Robinson said “In fact, climate science is a very simple discipline. The data is [are] very limited and very easily understood—as is illustrated in our review article…”7 I wonder what percentage of climatologists or Earth scientists would agree with Robinson about this. Robinson doesn’t seem to have much respect for their area of specialization. What reaction might Robinson have if scientists who are not chemists called his area of research on “deamidation of peptides and proteins”8 a “very simple discipline with very limited data which are very easily understood”. I think that the American public would be interested in knowing the views of a more restricted sample than the one used by Robinson. For the main hypothesis concerning human-caused global warming, it would be desirable to know the opinions of scientists with doctoral degrees in climatology or Earth science who had spent most of their lives studying the relevant phenomena. A survey of a large random sample of these scientists would be illuminating and helpful.

There are other flaws in Robinson’s project. If Robinson had been conducting a real survey rather than a petition drive, he would not have allowed three different ways for persons to participate in his project. Instead he would have arranged for persons to participate in only one way; he would have randomly selected participants from a well-defined, qualified and relevant population of scientific experts. Furthermore, in his petition project Robinson simply asked persons with science degrees to sign the petition if they agreed with its content. But did they agree with all 20 overlapping propositions embedded in the four sentences of the petition? Did they agree with most of them? Did they agree with at least 50% of them? We don’t know. In a real survey, Robinson would have constructed a questionnaire in which his respondents could have addressed each of the 20 propositions in which he was interested or possibly each of the main propositions actually stated in Al Gore’s popular book, An Inconvenient Truth, for which Robinson expresses great disdain.9 At the least, in a survey Robinson would have provided five response options for each proposition, something like “strongly disagree, moderately disagree, neither disagree nor agree, moderately agree, and strongly agree”. Or he might have provided a similar scale using anchors such as: “definitely false, probably false, uncertain if false or true, probably true, definitely true”. These response options would have allowed participants the opportunity to more fully express the subtlety and variety of their positions. Robinson may be a brilliant chemist, but he seems to know almost nothing about the behavioral sciences, especially about conducting sound scientific surveys.

Finally, the petition drive can be viewed as an “attempt to persuade” since it included the article reviewing the literature on global warming written by Robinson himself and two others, and it included the cover letter of endorsement from Seitz. The article and cover letter are bound to be biased towards Robinson’s point of view. If Robinson had been interested in finding the truth about expert opinion instead of manipulating that opinion, he would have done one of the following: 1) Sent a questionnaire with no accompanying review article or endorsement letter. (Probably the best option.) 2) Sent a review article not written by himself but by an independent expert representative of qualified climatologists. Or 3) Sent two review articles by two qualified climatologists from different perspectives, reaching different conclusions about humancaused global warming.

In conclusion, through his Global Warming Petition Project, Arthur Robinson has solicited the opinions of the wrong group of people in the wrong way and drawn the wrong conclusions about any possible consensus among relevant and qualified scientists regarding the hypothesis of human-caused global warming. His petition is unqualified to deliver answers about a consensus in which the public is interested. He has a right to conduct any kind of petition drive he wishes, but he is not ethically entitled to misrepresent his petition as a fair reflection of relevant scientific opinion. He has confused his political with his scientific aims and misled the public in the process.

The Author, Gary Whittenberger, is a free-lance writer and psychologist, living in Tallahassee, Florida. He received his doctoral degree from Florida State University after which he worked for 23 years as a psychologist in prisons. He has published many articles on science, philosophy, psychology, and religion, and their intersection.

  1. Robinson, Arthur. 2008. “Purpose of Petition in Global Warming Petition Project.”
  2. Robinson, Arthur. 2008. “Frequently Asked Questions in Global Warming Petition Project.”
  3. American Men and Women of Science. GALE CENGAGE Learning.
  4. Robinson, A. B., Robinson, N. E., and Soon, W. “Environmental Effects of Increased Atmospheric Carbon Dioxide.” Journal of American Physicians and Surgeons, 2007, 12, 7990.
  5. Robinson, Arthur. “Qualifications of Signers in Global Warming Petition Project.” Ibid.
  6. Solomon, Lawrence. 32,000 deniers. Posted May 16, 2008, 7:20 PM, by Jeff White in Financial Post.
  7. Robinson, Arthur. 2008. E-mail communication to Howard Kessler, June 17.
  8. Oregon Institute of Science and Medicine.
  9. Gore, Al. 2006. An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It. Rondale Books. website banner

This week at, Michael Shermer blogs about his trip to the big science conference in Puebla, Mexico called “City of Ideas,” in which he and Dan Dennett debated Dinesh D’Souza and John Esposito on “Is Religion a Force for Good or Evil in the World?”

While you’re there be sure to read the blogs posts of the other Skepticbloggers: Brian Dunning, Kirsten Sanford, Mark Edward, Phil Plait, Ryan Johnson, Steven Novella, and Yau-Man Chan.

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