Scientists Crack Greenland’s Disappearing Lakes Enigma — Global Warming Clues Hidden In Melt

INQUISITR.COM / Science
By Shelley Hazen
Published on: 2015-06-04T11:19:34
global warming

For years, scientists were confused by a strange phenomenon–disappearing lakes in Greenland. Now they’ve finally solved the mystery, with results that form a more complete picture of global warming.

The disappearing lakes in question sit on top of Greenland’s ice sheet, and somehow manage to drain billions of gallons of water in just hours, LiveScience reported. Evidently, the volume rivals the force of Niagra Falls. For instance, Greenland’s North Lake can drain 12 billion gallons in two hours.

Long ago, scientists determined that the water was draining through cracks that formed right beneath the disappearing lakes and extended to the bottom of the glacier. But still, researchers had no idea where the cracks even came from.

A new study just released has answered the question. According to Reuters, Greenland‘s sheet is infused with vertical shafts, called moulins. These provide a conduit for meltwater from the disappearing lakes, and through this route, it gets underneath it and lifts it up. The result: cracks.

Study co-author Laura Stevens explained it in more colorful terms for Tech Times.

“In some ways, ice behaves like Silly Putty — if you push up on it slowly, it will stretch; if you do it with enough force, it will crack. Ordinarily, pressure at the … surface is directed into the lake basin, compressing the ice together. But, essentially, if you push up and create a dome instead of a bowl, you get tension that stretches the surface apart.”

The force behind Greenland’s disappearing lakes may have implications for the study of sea level rise as it relates to global warming; scientists will be able to figure out the glacier’s contribution. Whenever a lake drains, it fills the ocean with tons and tons of water, also making it easier for ice to flow away from shore, Reuters explained.
This study shows that the most vulnerable are at lower, warmer elevations. Those at higher altitudes usually hold much more water, but they’re less likely to experience the cracks that drain out all that water.

“Our discovery will help us predict more accurately how (this) will affect ice sheet flow and sea level rise as the region warms in the future … It’s half of the equation of how (it) contributes to sea level rise, with the other half being the years when the (glacier) melts quicker than the snow is deposited.”

[Photo Courtesy Joe Raedle/Getty Images]