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HindustanTimes Thu,23 Oct 2014

Life and Universe

Earth losing 150bn tons of ice annually?
ANI
London, February 10, 2012
First Published: 14:45 IST(10/2/2012)
Last Updated: 20:55 IST(10/2/2012)

Greenland, Antarctica and global glaciers and ice caps lost roughly 8 times the volume of Lake Erie from 2003-2010, a new study has revealed.

According to the study led by the University of Colorado Boulder, earth's glaciers and ice caps outside of the regions of Greenland and Antarctica are shedding roughly 150 billion tons of ice annually.

HimalayasThe research effort is the first comprehensive satellite study of the contribution of the world’s melting glaciers and ice caps to global sea level rise and indicates they are adding roughly 0.4 millimeters annually, said University of Colorado Boulder physics Professor John Wahr, who helped lead the study.

The measurements are important because the melting of the world’s glaciers and ice caps, along with Greenland and Antarctica, pose the greatest threat to sea level increases in the future, Wahr said.

The researchers used satellite measurements taken with the Gravity Recovery and Climate Experiment, or GRACE, a joint effort of NASA and Germany, to calculate that the world’s glaciers and ice caps had lost about 148 billion tons, or about 39 cubic miles of ice annually from 2003 to 2010.

The total does not count the mass from individual glacier and ice caps on the fringes of the Greenland and Antarctic ice sheets - roughly an additional 80 billion tons.

“This is the first time anyone has looked at all of the mass loss from all of Earth''s glaciers and ice caps with GRACE,” said Wahr.

“The Earth is losing an incredible amount of ice to the oceans annually, and these new results will help us answer important questions in terms of both sea rise and how the planet’s cold regions are responding to global change,” he noted.

The total mass ice loss from Greenland, Antarctica and all Earth’s glaciers and ice caps from 2003 to 2010 was about 1,000 cubic miles, about eight times the water volume of Lake Erie, said Wahr.

“The total amount of ice lost to Earth’s oceans from 2003 to 2010 would cover the entire United States in about 1 and one-half feet of water,” said Wahr, also a fellow at the CU-headquartered Cooperative Institute for Research in Environmental Sciences.

The vast majority of climate scientists agree that human activities like pumping huge amounts of greenhouse gases in the atmosphere is warming the planet, an effect that is most pronounced in the polar regions.

One unexpected study result from GRACE was that the estimated ice loss from high Asia mountains -- including ranges like the Himalaya, the Pamir and the Tien Shan -- was only about 4 billion tons of ice annually. Some previous ground-based estimates of ice loss in the high Asia mountains have ranged up to 50 billion tons annually, Wahr said.

According to the GRACE data, total sea level rise from all land-based ice on Earth including Greenland and Antarctica was roughly 1.5 millimeters per year annually or about 12 millimeters, or one-half inch, from 2003 to 2010, said Wahr.

The finding is being published in the online edition of the journal Nature.


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