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Broadcast: January 10, 2003
By George Grow
This is the VOA Special English ENVIRONMENT REPORT.
American scientists say rising temperatures on Earth's surface are forcing animals and plants to move to cooler areas and make other changes. Their studies found that warmer weather is causing many kinds of wildlife to leave their native environments. They also found that such natural events as tree flowering and long-distance travel by birds are now happening earlier in the year. Nature magazine reported the findings.
The scientists say the result of these changes could be environmental damage and local losses of wildlife. They also warn that some creatures could disappear completely.
Plants and animals have always had to react to changing environments. However, the climate is now changing faster than ever before. Many scientists blame heat-trapping industrial gases for the warmer weather.
Camille Parmesan is a biologist at the University of Texas at Austin. She organized one of the studies with economist Gary Yohe of Wesleyan University in Middletown, Connecticut . They examined other studies that followed the movements of about one-thousand-seven-hundred kinds of wildlife over many years. They used mathematical programs to make sure that only the best information was studied.
Their most detailed effort involved ninety-nine kinds of birds, insects and plants in North America and Europe. They found that the territory where these plants and animals live has moved north by an average of six kilometers every ten years. In Europe, some butterflies now live as much as one-hundred kilometers to the north because of changes linked to higher temperatures.
Professors Parmesan and Yohe used similar methods to examine one-hundred-seventy-two kinds of wildlife. They examined the timing of events in the spring, such as the appearance of flowers and the reproduction of animals. They found that these events happened an average of two days earlier than normal every ten years.
In the second study, scientists at Stanford University in Palo Alto, California examined wildlife and climate information from one-hundred-forty-three studies. They found that about eighty percent of the creatures studied had made changes because of warmer weather.
1. climate [5klaImIt] n. 气候, 风土, 思潮 |