题型:阅读理解 题类:常考题 难易度:困难
山东省淄博实验中学、淄博五中2019届高三上学期英语第一次教学诊断试卷
Air travel can be annoying. But research now suggests global warming could make it much worse. To get off the ground in really hot weather, planes may be forced to carry fewer passengers. That might mean a little more space, which would be good. However, it also would make the passengers pay more.
Average air temperatures around the world are rising because people are polluting the air with an increasing number of greenhouse gases, which, such as carbon dioxide, are a byproduct (副产品) of burning fuels. Those warmer temperatures can influence an airplane's ability to fly because air molecules (分子) spread out more as the air warms. This produces less lift under a plane's wings, so a plane must be lighter to take off in hot weather than on cooler days.
It can even prove too dangerous for some planes to attempt a take-off. A record of June heat wave in the American Southwest, for instance, caused flight cancellations in Phoenix, Ariz. One airline's planes were cleared to operate only up to 47.8 degree Celsius. On June 20, Phoenix reached 48.3℃!
Radley Horton is a climate scientist at Columbia University. Two years ago, he and his graduate student Ethan David Coffel studied the impact of warming at four U.S. airports and found that warming of track could triple (使成三倍) the number of days when planes face weight restrictions. Later, they explored the impact of rising temperatures on live types of commercial planes flying out of 19 of the world's busiest airports. In the coming decades, as many as one to three out of every 10 flights that take off during the hottest time of day could face weight. That would be equal to taking a dozen people off the plane, the researchers calculated.
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