Journalists increasingly are reporting that scientists have reached a consensus on global warming. Close examination of the evidence cited to support these claims, however, reveals that such claims simply don't hold water:
Claim: Scientists agree that failing to respond to the threat of global warming now could prove disastrous for some parts of the globe.
Fact: A survey of over 400 German, American and Canadian climate researchers conducted by the Meteorologisches Institut der Universitat Hamburg and the GKSS Forschungszentrum found that 67% of those surveyed either disagreed or were uncertain about the proposition that global warming will occur so quickly that lack of preparation could prove disastrous.
Claim: Thousands of scientists have signed letters and petitions alerting the public to the dangers of global warming.
Fact: One of the letters often cited to support this claim was issued by Ozone Action. A close examination of that letter revealed that only 10% of the letter's signatories had backgrounds in climate science. Worse, landscape architects, a gynecologist, and a practitioner of traditional Chinese medicine are among the signatories.
Claim: 2,500 United Nations-sponsored scientists have concluded that human greenhouse gas emissions are warming the temperature of the planet.
Fact: This claim is based on the fact that the United Nations Intergovernment Panel on Climate Change (IPCC) issued a report suggesting a "discernible human influence" on climate change. While several thousand scientists were consulted in crafting the report, not all of them agreed with its conclusions. As Dr. John W. Zillman, one of these scientists noted: "[The IPCC was] meticulous in insisting that the final decision on whether to accept particular review comments should reside with chapter Lead Authors... Some Lead Authors ignored valid critical comments or failed to... reflect dissenting views..." The report was therefore the result of a political rather than a scientific process.
Claim: The majority of scientists believe global warming is a process underway and that it is human-induced.
Fact: A 1992 Gallup survey of climatologists found that 81 percent of respondents believed that the global temperature had not risen over the past 100 years, were uncertain whether or not or why such warming had occurred, or believed any temperature increases during that period were within the natural range of variation. Further, a 1997 survey conducted by American Viewpoint found that state climatologists believe that global warming is largely a natural phenomenon by a margin of 44% to 17%.
Sources: National Policy Analysis Paper #177 (The National Center For Public Policy Research) and Eco-Sanity (The Heartland Institute).
Talking Points on the Economy: Environment #38, published by The National Center for Public Policy Research, February 8, 1998