In DepthClimate

Antarctic ice melt 125,000 years ago offers warning

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Science  21 Dec 2018:
Vol. 362, Issue 6421, pp. 1339
DOI: 10.1126/science.362.6421.1339

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Some 125,000 years ago, during the last brief warm period between ice ages, Earth was flooded, with sea levels 6 to 9 meters higher than they are today. Temperatures during this time, called the Eemian, were barely higher than in today's greenhouse-warmed world. Scientists have now identified the source of all that water: a collapse of the West Antarctic Ice Sheet. Glaciologists worry about the present-day stability of this formidable ice mass. Its base lies below sea level, at risk of being undermined by warming ocean waters, and glaciers fringing it are retreating fast. The discovery, teased out of a sediment core and reported at a meeting of the American Geophysical Union in Washington, D.C., provides evidence that the ice sheet disappeared in the recent geological past under climate conditions similar to today's. The Eemian is not a perfect analog, as its sea levels were likely driven by slight changes in Earth's orbit and spin axis. But the work, if it holds up, could suggest the recent melt at the ice sheet is the start of a similar collapse, rather than a short-term variation.