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SOURCE: National Geographic

DATE: December 13, 2017

SNIP: Scientists sounding the seabed off Antarctica have uncovered some surprising episodes from the continent’s history: The East Antarctic Ice Sheet, they say, experienced a series of dramatic retreats in the distant past—retreats that were often punctuated by catastrophic floods of meltwater that erupted from beneath the ice sheet and left deep scars in the seafloor.

The ice covering East Antarctica, more than 12,000 feet thick in many places, has long been considered more stable and permanent than the West Antarctic Ice Sheet —and thus more likely to weather global warming unscathed. But the new research, published this week in Nature by Sean Gulick of the University of Texas and his colleagues, reinforces a growing concern that large swaths of East Antarctica are more vulnerable than once thought.

In recent years scientists have mapped the East Antarctic bedrock with ice-penetrating radar and found that, like West Antarctica, it includes large regions that plunge thousands of feet below sea level. Because they sit on such low ground, those areas of the ice sheet are susceptible to melting by deep, warm ocean currents.

One of the biggest is the Aurora Subglacial Basin. Much of the ice there flows to the sea through the Totten Glacier, which has been found to be thinning rapidly.