Both of these effects are due to warming. Because the atmosphere is warmer, it holds more moisture, so you get more snow. But because it's warmer, the edges of the ice are breaking up.

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A little bit of change in one of these things could throw it all out of balance and, evidently, that is what is going on.

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It's a big place down there, and until now it has been very hard to get a handle on what's happening to the whole ice sheet. The changes we are seeing are quite clearly global warming at work.

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