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GLOBAL WEATHER: WINDS OF CHANGE
By Sean Henahan, Access Excellence
Seattle, WA (2/14/97)
The Pacific Ocean appears to play a hitherto unexpected role in
regulating the Earth's temperature and could be counteracting global warming, report scientists from Columbia University.
Climatologists have observed a steady increase in atmospheric temperatures over the past century. The new research indciates that as temperatures have increased, the air-ocean circulation system in the tropical Pacific has also picked up speed. Moreover, it appears to be redistributing heat to regions where it dissipates more easily, leading to a reduction in warming," the scientists reported. This thermostat like phenomenon, which is related to the El Nino effect has largely been underestimated or overlooked in computer models used to simulate Earth's climate, the models that are used to forecast how the climate will change as industrial pollutants build up in the atmosphere. Indeed, this thermoregulatory effect of the Pacific Ocean may explain why global temperatures in the 20th century have risen only half as much as the computer models predicted. The researchers, working at the Lamont-Doherty Earth Sciences Research Institute in Palisades, N.Y.,believe the ocean and atmosphere in the tropical Pacific region interact in a series of events:
"It is notable that the eastern equatorial Pacific shows a cooling trend despite the strong and frequent El Nino events in the period after 1975," the scientists said. El Nino is created by the same tropical Pacific ocean-atmosphere dynamics. During an El Nino, trade winds slacken and the pool of warm waters in the western Pacific begins to migrate back eastward, accompanied by a center of tropical rainfall. The shifting conditions in the tropical Pacific dramatically rearrange global wind and rainfall pattern, often causing droughts, floods and other destructive weather around the world. The phenomenon is second only to the seasons themselves in driving worldwide weather patterns and has impacts on climate from the Far East, Australia and southern Africa to South America and the United States. While tropical Pacific ocean-atmosphere dynamics may delay global warming, the scientists warn that the changing pattern of tropical Pacific temperatures could produce long-term ocean-atmospheric changes. "These changes in regional climate and climate variability over much of the Earth that would be likely to have substantial social and economic consequences," they said. The research appeared in the Feb. 14, 1997 issue of Science.
Related information on the Internet Atmosphere and Climate Resources
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