Global warming could pose a greater risk to tropical insects and other species sensitive to the slightest shifts in temperature than to creatures living in the world's tundra, scientists warned in the Proceedings of the National Academy of Sciences Tuesday.
While cold weather animals are used to huge temperature changes, tropical species live under a much smaller temperature range and face a bigger risk of extinction with an increase of just two or four degrees Celsius, according to a team led by University of Washington scientists.
"In the tropics many species appear to be living at or near their thermal optimum, a temperature that lets them thrive," said Joshua Tewksbury, an assistant professor of biology at the Seattle, Washington university."But once temperature gets above the thermal optimum, fitness levels most likely decline quickly and there may not be much they can do about it," he said.
For their research, the scientists examined daily and monthly global temperatures from 1950 to 2000.
"Many tropical species can only tolerate a narrow range of temperatures because the climate they experience is pretty constant throughout the year," said Curtis Deutsch, an assistant professor of atmospheric and oceanic sciencesat the University of California, Los Angeles.
"Our calculations show that they will be harmed by rising temperatures more than would species in cold climates," he said.
"Unfortunately, the tropics also hold the large majority of species on the planet," said Deutsch.
Source:Xinhua/Agencies
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