WASHINGTON, D.C.--A group of distinguished American scientists yesterday confirmed that the world is warming, and that humans are to blame. The quick, 1-month analysis by an 11-person committee of the U.S. National Research Council (NRC) came to essentially identical conclusions as an earlier, 3-year international study.
After President George Bush in February rejected the Kyoto Protocol for limiting greenhouse gas emissions, the White House asked the National Academy of Sciences for help sorting out climate change science. Tapped for the job were 11 meteorologists, oceanographers, and climate scientists. Only two had participated in the international assessment conducted by the U.N.-sponsored Intergovernmental Panel on Climate Change (IPCC). Prominent figures in the panel included Richard Lindzen of the Massachusetts Institute of Technology, the most credentialled greenhouse contrarian in the U.S., and James Hansen of NASA's Goddard Institute for Space Studies in New York City, who ignited a firestorm of media attention in 1988 when he told Congress that greenhouse warming had arrived.
Despite the committee's breadth of views, its report echoed the IPCC's conclusion that humans are at least partly to blame for the current climate change (ScienceNOW, 22 January). It also concluded that "global warming could well have serious adverse societal and ecological impacts by the end of this century." That message is what environmentalists and activist scientists had hoped to hear, and is sure to be harped on when Bush talks next week with European leaders, in part about what he intends to do about global warming.
The White House also got what it may have been after all along: an upfront review of the ambiguities in greenhouse science. Uncertainty remains in the effects of changing cloud cover, the realism of climate models, and elsewhere, the panel said. The committee reiterated the IPCC estimates that the uncertainties mean the world might warm by a modest 1.4ºC by the end of the century or by a sizzling 5.8ºC. The White House will likely add this U.S.-expert-certified uncertainty to its arguments that the unratified Kyoto Protocol would damage the economy and unfairly relieve developing countries of any commitments to reducing their greenhouse gas emissions.