Warmer Summers May Actually Slow Down Greenland Glacier Flow

by Marlo Lewis on February 2, 2011

in Blog, Features

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In his Academy Award-winning scare-u-mentary, An Inconvenient Truth, Al Gore warned that global warming could raise sea levels by 20 feet, and implied it could happen in our lifetimes or those of our children.

Gore explained that the Greenland Ice Sheet could break apart and slide into the sea as “moulins” (ice crevices and fissures) transfer surface melt water during warm summers down to the underlying bedrock, thereby lubricating glacial ice streams and accelerating their seaward flow.

In CEI’s July 2009 film Policy Peril, climatologist Dr. Patrick Michaels handily debunked Gore’s 20-foot hobgobblin. A month later, I provided additional information and links to relevant studies here.

Gore’s thesis was always a bit goofy, because his main “evidence” was a 2002 study in Science magazine finding that summer ice melt enhanced the annual flow rate of certain Greenland glaciers by a few percentage points — in other words, by several meters. For perspective, the Greenland Ice Sheet is about 2,500 kilometers long and 1,000 kilometers wide.

Last week (Jan. 27), Science Daily profiled a study that pours more cold water on Gore’s doomsday scenario. The review article could not be more provocatively titled: “‘Hidden Plumbing’  Helps Slow Greenland Ice Flow: Hotter Summers May Actually Slow Down Glaciers.”

Science Daily explains the paradoxical finding as follows: “The authors suggest that in these years the abundance of melt-water triggers an early switch in the plumbing at the base of the ice, causing a pressure drop that leads to reduced ice speeds.” Implication? “If that’s the case, increases in surface melting expected over the 21st century may have no affect on the rate of ice loss through flow.”

Svend Hendriksen February 2, 2011 at 2:24 pm

The weight of the Ice Cap drives the speed of the glacier, if just 1 mm melt on a 200.000 km2 area reduce the weight with about 200.000.000 tonnes (ie less speed)

So NO hokus pokus. it's just a matter of weight, nothing more or less.

Kind regards

Dr. homor Seksual February 21, 2011 at 1:32 pm


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