ICESat documents ‘profound polar thinning’


in Geek stuff, Science, The environment

NASAs Ice, Cloud and Land Elevation Satellite (ICESat) generated recently published data showing “that all latitudes of the Greenland ice sheet are affected by dynamic thinning – the loss of ice due to accelerated ice flow to the ocean” as well as evidence of “extensive thinning in Antarctica, affecting the ice sheet far inland.”

This is, of course, bad news when it comes to the magnitude of sea level rise to expect in response to climate change. Most analyses of sea ice focus on area covered, not on the potentially more meaningful figure of total ice volume. In addition to raising concern about sea level rise, melting icesheets produce a positive feedback effect as darker surfaces are exposed to sunlight. They also risk disrupting ocean currents where salinity is an important driver.

More information is in Nature: “Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets.”

{ 2 comments… read them below or add one }

. October 15, 2009 at 10:13 am

Arctic to be ‘ice-free in summer’
By David Shukman
Science and environment correspondent, BBC News

The Arctic Ocean could be largely ice-free and open to shipping during the summer in as little as ten years’ time, a top polar specialist has said.

“It’s like man is taking the lid off the northern part of the planet,” said Professor Peter Wadhams, from the University of Cambridge.

Professor Wadhams has been studying the Arctic ice since the 1960s.

He was speaking in central London at the launch of the findings of the Catlin Arctic Survey.

The expedition trekked across 435km of ice earlier this year.

Led by explorer Pen Hadow, the team’s measurements found that the ice-floes were on average 1.8m thick – typical of so-called “first year” ice formed during the past winter and most vulnerable to melting.

. February 19, 2010 at 4:25 pm

“Weaver points out that the 2007 IPCC report was, in fact, conservative with its conclusions. At the time it didn’t have access to more accurate satellite data from NASA’s Gravity Recovery and Climate Experiment (GRACE) mission.

The new GRACE data, said Weaver, “has revealed that Greenland has been melting rather dramatically. Also, not only is Antarctica melting, but West Antarctica is melting quite rapidly.”

The GRACE data and the Marshall and Barber studies are some of the more recent developments. They reinforce hundreds, even thousands of climate-change studies from the past two decades that form pieces of this complex puzzle. But there are enough pieces in place that we’re starting to see an image, and it doesn’t look good.”

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