Greenland's Ice Sheets...

They aren't in a hurry to slide into the ocean...

Much noise has been made about how water lubricates the base of Greenland's ice sheet, accelerating its slide into the oceans. In a rare "good news" announcement, climatologists now say the ice may not be in such a hurry to throw itself into the water after all. Mother Nature, it seems, has given it brakes.

Since 1991, the western edge of Greenland's ice sheet has actually slowed its ocean-bound progress by 10%, say the team, who have studied the longest available record of ice and water flow in the region.

Greenland's mighty ice sheet has enough water locked away to raise global sea level 6.5 metres were it to melt. Each summer, vast lakes of meltwater form on its surface. The water seeps through cracks in the kilometer-thick ice to bedrock, where it acts as a lubricant. The sheet can move up to twice as fast in the summer, when meltwater is flowing, as when it is not.

Many fear a positive feedback loop, whereby the accelerating flow will bring more ice down out of the mountains and toward warmer temperatures near sea level. Roderik Van De Waal and colleagues at Utrecht University in the Netherlands now say there is no evidence this will happen.