Imagine you're canoeing the Niagara River when you notice mist ahead. You're still quite a distance from Niagara Falls, but the river's swift: There's no turning back. Two separate studies published last spring suggest that climate change has carried the West Antarctic Ice Sheet, or WAIS, across a similar threshold. The glaciers that flow off WAIS and dump ice into the sea already have contributed nearly 10 percent to the recent increase in global sea levels. Now, warming seawater intruding underneath has loosened the glaciers' grip on bedrock, speeding their flow toward the sea and causing increasing amounts of ice to break off into the ocean.
展开▼
