Greenland's ice cap is melting at a frighteningly fast rate

The vast ice cap that covers Greenland nearly three miles thick is melting faster than ever before on record, and the pace is speeding year by year, according to global climate watchers gathering data from twin satellites that probe(探测) the effects of warming on the huge northern island. The consequence is already evident in a small but ominous(不祥的)rise in sea levels around the world, at a pace that is also accelerating, the scientists say.