[单项选择] 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°C 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 melt, thus raising sea level several metres and severely flooding coastal cities. Also, the increase in atmospheric temperature would lead to great changes in the climate of the northern hemisphere, 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 o
A. ice would soon cover*the northern hemisphere
B. the greenhouse effect could work to the advantage of the earth
C. the best way to overcome the cooling effect would be to burn more fuels
D. the increased levels of carbon dioxide in the atmosphere could warm up the earth even more quickly