Further evidence of polar ice melting

The Guardian reports, 1st September 2014: “German researchers have established the height of the Greenland and Antarctic ice caps with greater precision than ever before. The new maps they have produced show that the ice is melting at an unprecedented rate.

The maps, produced with a satellite-mounted instrument, have elevation accuracies to within a few metres. Since Greenland’s ice cap is more than 2,000 metres thick on average, and the Antarctic bedrock supports 61% of the planet’s fresh water, this means that scientists can make more accurate assessments of annual melting.

Dr Veit Helm and other glaciologists at the Alfred Wegener Institute’s Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, report in the journal The Cryosphere that, between them, the two ice sheets are now losing ice at the unprecedented rate of 500 cubic kilometres a year.

New elevation models of Antarctica and Greenland by ESA’s CryoSat satellite

New elevation models of Antarctica (right) incorporates 61 million measurements and Greenland 7.5 million measurements from ESA’s CryoSat satellite collected throughout 2012.
Photograph: ESA

Over a three-year period, the researchers collected 200m measurements in Antarctica and more than 14m in Greenland. They were able to study how the ice sheets changed by comparing the data with measurements made by Nasa’s IceSat mission.

Greenland’s volume of ice is being reduced at the rate of 375 cubic km a year. In Antarctica, the picture is more complex as the West Antarctic ice sheet is losing ice rapidly, but is growing in volume in East Antarctica. Overall, the southern continent — 98% of which is covered with ice and snow — is losing 125 cubic km a year. These are the highest rates observed since researchers started making satellite observations 20 years ago.

“Since 2009, the volume loss in Greenland has increased by a factor of about two, and the West Antarctic ice sheet by a factor of three,” said Angelika Humbert, one of the report’s authors.

Source: The Guardian, 1st September 2014. For the full text, see
www.theguardian.com/environment/2014/sep/01/new-satellite-maps-show-polar-ice-caps-melting-at-unprecedented-rate

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