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Back in 2006, scientists in Greenland made an alarming observation: Glaciers were crumbling into the ocean twice as fast. And not in little cocktail-sized cubes, either: Glaciologist Jason Box accurately predicted the spot where a hunk four times the size of Manhattan would later shear off into the sea.
At the same time, the inland top of the ice sheet was thawing at record levels; last summer, for the first time in 150 years, its entire surface was melting. By summer’s end, this water alone raised sea levels all over the world by a millimeter.
As Box told our Climate Desk Live audience in January, rising air and water temperatures—driven by greenhouse gas emissions—are to blame. And with more warming on the way, he made a grim prediction: melting from Greenland and the world’s other land-based glaciers could ultimately raise global sea levels by 69 feet, Box warns.
But don’t start building your flood-proof Ark quite yet: Advanced imaging released in August suggested the ice sheet is capable of quickly reversing its melting habit. And a study out today in Nature finds that the sped-up ice loss on the water’s edge, while still a problem, is unlikely to get much worse, even with a big rise in global temperatures. Taken together, these two studies suggest that Greenland’s ice melt problem isn’t as bad as experts like Box had predicted.
For the Nature study, Faezeh Nick, a researcher at Norway’s University Centre in Svalbard, led a team that took the closest-ever look at so-called “outlet glaciers,” the 200 or so outermost arms of the ice sheet that flow straight into the sea. Their findings suggest that the increase in melting rate is about to slow down, suggesting that in a medium warming scenario these glaciers will likely contribute just 19-30 millimeters to global sea levels by 2100. That’s much less than if the current acceleration of melting were to persist, but still a noteworthy share of the quarter- to half-meter rise projected by the UN’s Intergovernmental Panel on Climate Change.
Scientists on the sailboat Gambo measure water temperature and salinity in front of a Greenland glacier. Faezeh M. Nick