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  3. Global warming, after all, isn’t just about hotter summers. As the earth’s temperatures rise, scientists speculate, there will b

Global warming, after all, isn’t just about hotter summers. As the earth’s temperatures rise, scientists speculate, there will b

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问题     Global warming, after all, isn’t just about hotter summers. As the earth’s temperatures rise, scientists speculate, there will be a lot more than warming going on. The change in ocean temperatures and sea levels will affect everything from rain patterns to wind direction. But how much of that is already happening, and how much is speculation?
    Though we’ve seen increasingly unusual weather patterns in recent years,it’s important to separate individual instances of extreme weather from the broader category of climate change. Those heavy snows from last winter, according to researchers at Columbia University, were the result of two large colliding weather fronts—probably just a natural aberration (越轨), rather than necessarily a symptom of climate change. And tornado in Brooklyn was definitely bizarre—it occurred not only in a part of the country not known for touchdowns,but also during an unusual time of day and season and in the midst of a regional drought. However,it can’t be precisely pinned on global warming.
    Still,recent research has begun to show that at least in some cases, those altered and extreme weather patterns can be definitively linked to global warming. A just-released analysis by researchers at Duke University shows that’s the case for summertime weather in the southeastern United States. Eleven of the past 30 summers were either abnormally wet or abnormally dry in the Southeastern states. And there were twice as many instances of " extreme" rainfall as there had been compared to the rainfall during the 30 preceding summers. Summer weather in that part of the country—along with that of the entire eastern U. S. .Western Europe,and North Africa,is influenced by the North Atlantic subtropical high (NASH) ,a high-pressure system that has intensified an average of 0.9 geo-potential meters (位势 米) every decade over the past 60 years.
    In layman’s terms,that means that the system extended higher and higher above sea level,making NASH more powerful. And its reach extended in other ways too; the area of the system grew, meaning that it came westward, closer to the eastern coast of the United States, and also increased its north-south movement. But slight shifts in NASH’s path can have a big impact;If NASH goes slightly more northward than usual，it can make for a dry summer; southward, and the summer is an extremely wet one. Researchers at Duke say they thoroughly investigated naturally occurring phenomena for the growth of NASH,but found no seemingly reasonable explanations. They concluded that the change is a result of alterations to the climate that were caused by humans.
    More dramatic are the claims that global warming could bring about or aggravate civil wars in Africa because of agricultural resources scarcity. That may or may not come about, but the broader lesson seems to be that even if science hasn’t yet formally connected all the dots on climate change,we should expect the unexpected.
What is the finding of the Duke University research?
选项 A、All altered and extreme weather patterns are linked to global warming.
B、Southeastern U. S. ’s abnormal summer was relevant to global warming.
C、Summers in southeast America were either abnormally wet or dry.
D、Abnormal summer weather in the entire U. S. was caused by NASH.
答案B
解析 事实细节题。原文第三段第二句指出，杜克大学的研究人员最近公布的一份分析报告显示，美国东南部反常的夏季天气就属于这种情况。它所指的情况在第一句中已经阐明：近期的研究已经开始证明至少某些天气变化或极端天气模式肯定与全球变暖有关系。因此，B)“美国东南部反常的夏季天气与全球变暖有关”，符合题意，故为本题答案。A)“所有天气变化和极端天气模式都与全球变暖有关”，与原文中的at least in some cases的限定不符，故排除；C)“美同东南部夏季的天气不是特别多雨就是特别干旱”，原文第三段第三句指出，在过去的30年里，美国东南部就有11个夏季或异常多雨或异常干燥，说明期间还有许多气候正常的年份，故排除；D)“整个美国的夏季异常天气都是由北大西洋副热带高压(NASH)造成的”，与原文不符，故排除。
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