January 23, 2001 - Toronto Star Top scientists call U.N. report on climate change misleading `Based on the science you
can't say Peter Calamai OTTAWA - Top scientists are urging caution in interpreting the latest dire warnings about climate change issued by a United Nations panel, especially claims that the world will get hotter over the next 100 years than previously forecast. ``Based on the science you simply can't make the statement that it is going to warm faster,'' said Andrew Weaver, a climate scientist at the University of Victoria and a lead author of the U.N. technical climate report. People making such statements didn't understand the science behind the U.N. report said Weaver, who holds the Canada Research Chair in atmospheric science. The 18-page report released in Shanghai, China, yesterday was a summary of a technical document of more than 1,000 pages to which hundreds of scientists contributed. Critics say the review, hammered out during four days of horse-trading among officials from 99 governments, was aimed at politicians and other non-scientist policymakers. Weaver's concerns were echoed by other climate experts in Canada and the U.S., including Gordon McBean, a former head of the Meteorological Service of Canada and key player in the previous U.N. climate study five years ago. ``It is misleading to say the situation is any worse,'' said McBean, now a University of Western Ontario professor who heads the Institute for Catastrophic Loss Reduction, which focuses on extreme climate events. However, Weaver and McBean both applauded the strong language of the report blaming people - especially the burning of fossil fuel - for the unprecedented rise in average global temperature. ----------------------------------------------- `Most
of the warming . . . ----------------------------------------------- ``There is new and stronger evidence that most of the warming observed over the past 50 years is attributable to human activities,'' declared the report. The scientific conclusions were leaked in October and have already been widely discussed. They include: A rise of average global surface temperatures of about 0.6 C during the 20th century with minimum night temperatures rising twice as much as maximum day temperatures in the last 50 years. A measured rise of 10 to 20 centimetres in average sea levels over the same period, mostly from the water expanding as it warmed. No evidence of any increase in tornadoes, thunderstorms or hail bursts. No significant change in the Antarctic ice cap since satellite measurements began in 1978. Suggestive evidence that natural charges, such a stronger sun, were mostly responsible for global warming early in the past century with greenhouse gases, such as carbon dioxide, taking over in the last quarter. The controversy over whether the Earth would warm faster than previously forecast arose from comparisons with the projections of computer climate models. In 1995, the models forecast an increase by 2100 in the global average surface temperature of between 1 and 3.5 C. The current report quotes a range of 1.4 to 5.8 C. But the detailed socio-economic assumptions fed into the computer climate models changed drastically over the five years. The report is the first of three to be released, with an over-all report to be approved in September. ``The public is led to think that hundreds, even thousands, of scientists formed a consensus about this report. The truth is that we're not even asked,'' said Richard Lindzen, a meteorologist at the Massachusetts Institute of Technology. |