The polar ice caps reflect 70%～80% sun's energy back into space,which enables a lower temperature for the polar oceans.If the ice caps melt,energy-less reflected,will warm the oceans,resulting their faster melting.Global warming will cause torrential rains、floods、hurricanes and other weather disasters,and the consequences will be disastrous.

In 1992,1700 world top scientists from the Union of Concerned Scientists,including most of the Nobel Prize winners,had called for global efforts to curb global warming.They said: "we have less than ten years or decades left for preventing the global warming which,however,once irretrievable,the hope of mankind will be very slim."

"The melting of the Antarctic ice sheet may cause a 6-meter sea level rise and some coastal cities,including New York、Bombay and Shanghai,will be flooded."Said James Hanson,a climate expert,during congressional hearings,"We must take urgent action for the situation is very serious."