A Dusty Greenland Is Speeding Up Glacial Melt b4in.org/q4Ro Greenland provides one of the best real-time visuals of climate change — cleaving glaciers the size of buildings cascading into the ocean as one long, slow river of ice returning to the sea. A new study shows that a layer of dust covering much of Greenland’s ice sheet could be speeding up this process. A paper published in the journal Nature Geoscience suggests that dust particles embedded in Greenland’s massive ice sheet are gathering more heat than the otherwise white, reflective surface would and causing melting to accelerate. The scientists write that “recent warming in the Arctic has induced an earlier disappearance of the seasonal snow cover, uncovering large areas of bare soil and thus enhancing dust erosion.” Dust absorbs the sunlight and re-radiates it as heat. This causes earlier snowmelt that in turn exposes ice beneath the snow sooner than otherwise would have been expected — creating a feedback loop. This reduction in reflectivity is generating a lower albedo, a term used to indicate how well a surface reflects solar energy, across the landmass. More than three-quarters of Greenland is covered by an ice sheet that can reach up to two miles in thickness. If all 684,000 cubic miles of ice melted it could raise sea levels by up to 24 feet. “Greenland’s melt already accounts for about 30 percent of current sea level rise, which has been 8 inches since the 1880s, though the rate has been increasing in recent decades,” reports Climate Central. “Dust gets transported to the Arctic by wind in the atmosphere,” Marie Dumont, a scientist at France’s meteorological agency who led the new study, told Climate Central. “High latitude sources of impurities can easily be redeposited on Greenland’s surface.” More b4in.org/q4Ro
Posted on: Tue, 10 Jun 2014 19:56:39 +0000
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