'Devastating' Melt of Greenland, Antarctic Ice Sheets Found

The Greenland and Antarctic ice sheets are now losing more than three times as much ice a year as they were 30 years ago, according to a new comprehensive international study. Phys.Org reports: Using 50 different satellite estimates, researchers found that Greenland's melt has gone into hyperdrive in the last few years. Greenland's average annual melt from 2017 to 2020 was 20% more a year than at the beginning of the decade and more than seven times higher than its annual shrinkage in the early 1990s. From 1992 to 1996, the two ice sheets -- which hold 99% of the world's freshwater ice -- were shrinking by 116 billion tons (105 billion metric tons) a year, two-thirds of it from Antarctica. But from 2017 to 2020, the newest data available, the combined melt soared to 410 billion tons (372 billion metric tons) a year, more than two-thirds of it from Greenland, said the study in Thursday's journal Earth System Science Data. Since 1992, Earth has lost 8.3 trillion tons (7.6 trillion metric tons) of ice from the two ice sheets, the study found. That's enough to flood the entire United States with 33.6 inches (almost 0.9 meters) of water or submerge France in 49 feet (nearly 15 meters). But because the world's oceans are so huge, the melt just from the ice sheets since 1992 still only adds up to a little less than inch (21 millimeters) of sea level rise, on average. Globally sea level rise is accelerating and melt from ice sheets has gone from contributing 5% of the sea level rise to now accounting for more than one-quarter of it, the study said. The rest of the sea rise comes from warmer water expanding and melt from glaciers.

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