2017届山西省大同县高三英语一轮阅读理解训练（3）及答案_高考复习指南

2017届山西省大同县高三英语一轮阅读理解训练（3）及答案

　　In the atmosphere, carbon dioxide acts rather like a one-way mirror or the glass in the roof of a greenhouse which allows the sun’s rays to enter but prevents the heat from escaping

　　According to a weather expert's prediction , the atmosphere will be 3℃ warmer in the year 2050 than it is today, if man continues to burn fuels at the present rate．If this warming up took place．the ice caps in the poles would begin to inch，thus raising sea level several meters and severely flooding coastal cities．Also．the increase in atmospheric temperature would lead to great changes in the climate of the northern hemisphere(北半球)，possibly resulting in an alteration of the earth’s chief food growing zones．

　　In the past，concern about a man-made warming of the earth has concentrated on the Arctic because the Antarctic is much colder and has a much thicker ice sheet．But the weather experts are now paying more attention to West Antarctic．which may be affected by only a few degrees of warming，in other words，by a warming on the scale that will possibly take place in the next fifty years from the burning of fuels．

　　Satellite pictures show that large areas of Antarctic ice are already disappearing．The evidence available suggests that a warming has taken place．This fits the theory that carbon dioxide warms the earth．

　　However, most of the fuel is burnt in the northern hemisphere，where temperatures seem to be falling．Scientists conclude，therefore ,that up to now natural influences on the weather have gone beyond those caused by man．The question is：Which natural cause has most effect on the weather?