A camera being lowered into a moulin during glacier research in Greenland. (Konrad Steffen/Cires)
From the International Herald Tribune http://www.iht.com/articles/2008/01/07/healthscience/ice.php
A scramble to understand Greenland’s melting ice sheets
By Andrew C. Revkin
Published: January 7, 2008
The ancient frozen dome cloaking Greenland is so vast that pilots have crashed into what they thought was a cloud bank spanning the horizon. Flying over it, one can scarcely imagine that this ice could erode fast enough to raise sea levels dangerously any time soon.
Along the flanks in spring and summer, however, the picture is very different. For a lengthening string of warm years, a lacework of blue lakes and rivulets of meltwater have been spreading ever higher on the ice cap. The melting surface darkens, absorbing up to four times as much energy from the sun as unmelted snow, which reflects sunlight. Natural drainpipes, called moulins, carry water from the surface into the depths, in some places reaching bedrock. The process slightly, but measurably, lubricates and accelerates the grinding passage of ice toward the sea.
Most important, many glaciologists say, is the breakup of huge semi-submerged clots of ice where some large Greenland glaciers, particularly along the west coast, squeeze through fjords as they meet the warming ocean. As these passages have cleared, this has sharply accelerated the flow of many of these creeping, corrugated, frozen rivers.
All of these changes have many glaciologists “a little nervous these days - shell-shocked,” said Ted Scambos, the lead scientist at the National Snow and Ice Data Center in Boulder, Colorado, and a veteran of both Greenland and Antarctic studies.
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