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Moulin bleu

Tunneling meltwater rivers enlarged by climate change help shuttle glacial ice to the sea less than previously thought.
November 25, 2013
Moulin bleu

Meltwater on the Greenland ice sheet forms surface flows that can eventually dive into moulins. These moulins deliver water to the base of the ice sheet, where it marginally affects the rate at which glaciers move to the sea. (CREDIT: Matthew Hoffman/LANL)

A rare morsel of good news about sea-level rise from the Greenland ice sheet

As major ice sheets melt and flow into the ocean—a process accelerated by climate change—the global sea level rises. This process is further sped up by the meltwater lubrication effect, in which meltwater rivers tunnel down from the surface of the ice sheet to its base via vertical shafts called moulins and, from there, help to convey glacial ice to the sea. New supercomputer simulations, however, based in part on field measurements from Greenland, show that that the lubrication effect will augment sea level rise by only a few percent above that caused by melting alone.

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