In the world of climate change, it is in the Earth’s cold regions where trends can most easily be seen. The cryosphere, where wa

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问题     In the world of climate change, it is in the Earth’s cold regions where trends can most easily be seen. The cryosphere, where water is found in solid form, is among the most sensitive regions to temperature change.
    The sensitivity of ice and snow to temperature changes is an early indicator of even relatively small differences, says University of Colorado at Boulder senior researcher Richard Armstrong. He has found that today’s receding and thinning sea ice, mountain glacier mass losses, decreasing snow extent, melting permafrost (永久冻土), and rising sea level are all consistent with war¬ming.
    Global mean temperatures have risen one degree Fahrenheit over the past 100 years, with more than half of the increase occurring in the last 25 years, observes Armstrong who is affiliated with the National Snow and Ice Data Center headquartered at CU-Boulder.
    "As slight as that may seem, it’s enough to make a difference," said Armstrong. "Now, long-term monitoring of a series of cold region, or cryospheric, parameters (参数) shows that for several decades the amounts of snow and ice around the world have been decreasing. "
    The extent of Arctic sea ice is shrinking by about 3 percent per decade, but the trends are not uniform. While recent studies have indicated that the ice thickness also had decreased over several decades, new information shows that the ice may have thinned rapidly, Armstrong said. Examination of springtime ice thickness in the Arctic Ocean indicates that the mean ice thickness decreased 1. 5 meters (4. 8 feet) between the mid-1980s and early 1990s.
    To mark its 25th anniversary, the National Snow and Ice Data Center has organized a special session at the 2001 Fall Meeting of American Geophysical Union, taking place this week in San Francisco, that illuminates overall changes in the cryosphere.
    The session begins Tuesday and extends through Thursday afternoon, with 75 contributions from all areas of cryospheric study. Papers and posters include examinations of lake and river ice, glacier dynamics, and mass ice balance studies in polar and continental glaciers, regional and polar snow cover trends, and variations in Canadian ice cap elevations.
According to Armstrong, ______.

选项 A、slight changes in global mean temperature are insignificant
B、the amounts of snow and ice around the world began to decrease in the 1990s
C、the past 100 years witnessed the greatest rise in global mean temperature in human history
D、the global mean temperature increased more than 0. 5 degree Fahrenheit in the last 25 years

答案D

解析 细节题。本题是问文中所涉及的Armstrong的观点。根据第三段,Armstrong认为全球平均气温在过去的100年间上升了1华氏度,而其中一半多的上升是发生在过去25年间。这并不意味着全球平均气温在过去的100年间的上升是在人类历史上最快的,所以C不对,而D符合。在第四段中又讲,他认为尽管这个数字看起来很小,但足以产生很大影响,因此A不对;而且他还说在过去几十年间世界冰雪量一直在减少,所以B不符合此意。故D是本题正确答案。
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