The Scientific Consensus on Global Warming

Naomi Oreskes is a history of science professor at UC San Diego. She has a piece in the Los Angeles Times today about the scientific consensus on global warming. A couple of weeks ago the Wall Street Journal ran an editorial by MIT professor Richard Lindzen, who said there was not a scientific consensus on the facts of global warming. Oreskes says Lindzen is wrong:

...Not a single paper in a large sample of peer-reviewed scientific journals between 1993 and 2003 refuted the consensus position, summarized by the National Academy of Sciences, that "most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations."

Since the 1950s, scientists have understood that greenhouse gases produced by burning fossil fuels could have serious effects on Earth's climate. When the 1980s proved to be the hottest decade on record, and as predictions of climate models started to come true, scientists increasingly saw global warming as cause for concern.

In 1988, the World Meteorological Assn. and the United Nations Environment Program joined forces to create the Intergovernmental Panel on Climate Change to evaluate the state of climate science as a basis for informed policy action. The panel has issued three assessments (1990, 1995, 2001), representing the combined expertise of 2,000 scientists from more than 100 countries, and a fourth report is due out shortly. Its conclusions — global warming is occurring, humans have a major role in it — have been ratified by scientists around the world in published scientific papers, in statements issued by professional scientific societies and in reports of the National Academy of Sciences, the British Royal Society and many other national and royal academies of science worldwide. Even the Bush administration accepts the fundamental findings. As President Bush's science advisor, John Marburger III, said last year in a speech: "The climate is changing; the Earth is warming."

To be sure, there are a handful of scientists, including MIT professor Richard Lindzen, the author of the Wall Street Journal editorial, who disagree with the rest of the scientific community. To a historian of science like me, this is not surprising. In any scientific community, there are always some individuals who simply refuse to accept new ideas and evidence. This is especially true when the new evidence strikes at their core beliefs and values.