[单项选择]In the atmosphere, carbon dioxide acts rather like a one-way mirror—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 melt, 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, possibly resulting in an alteration of the 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. the climate of the world should be becoming cooler
B. it will take thousands of years for the inertia of the earth’s climate to take effect
C. the man-made warming effect helps to increase the solar effect
D. the new Ice Age will be delayed by the greenhouse effect