Greenland ice cap may be melting at triple speed

The world's second largest ice cap may be melting three times faster than indicated by previous measurements, according to newly released gravity data collected by satellites.

The Greenland Ice Sheet shrank at a rate of about 239 cubic kilometres per year from April 2002 to November 2005, a team from the University of Texas at Austin, US, found. In the last 18 months of the measurements, ice melting has appeared to accelerate, particularly in southeastern Greenland.

"This is a good study which confirms that indeed the Greenland ice sheet is losing a large amount of mass and that the mass loss is increasing with time," says Eric Rignot, from NASA's Jet Propulsion Laboratory in Pasadena, California, US, who led a separate study that reached a similar conclusion earlier in 2006 (See Greenland's glaciers are speeding to the ocean). His team used satellites to measure the velocity of glacier movement and calculate net ice loss.

Yet another technique, which uses a laser to measure the altitude of the surface, determined that the ice sheet was losing about 80 cubic kilometres of ice annually between 1997 and 2003. The newer measurements suggest the ice loss is three times that.

"Acceleration of ice mass loss over Greenland, if confirmed, would be consistent with proposed increased global warming in recent years, and would indicate additional polar ice sheet contributions to global sea level rise," write the University of Texas researchers in the journal Science.

	Greenland Ice Cap May be Melting at Triple Speed	New Scientist	Thu Aug 10	0
	Greenland melt 'speeding up'	BBC News	Sat Aug 12	1
	Greenland's Ice Cap is Melting at a Frighteningly Fast Rate	Common Dreams	Fri Aug 11	0