CRYOSAT DATA CONFIRM ANTARCTIC ICE LOSS

A new European Space Agency (Esa) Cryosat satellite study shows that Antarctica is now losing about 160 billion tonnes of ice a year to the ocean, twice as much as in the last survey.
http://www.bbc.co.uk/news/science-environment-27465050 

Cryosat was launched by Esa in 2010. It has two antennas slightly offset from each other, enabling the detection of not just the height of the ice sheet but the shape of its slopes and ridges. Cryosat is thus more sensitive to details at the steep edges of the ice sheet, where the thinning is most pronounced. 

The ice loss is sufficient to increase global sea levels by around 0.43 mm per year. By comparison, total loss of the Antarctic ice could cause a 58 metre sea level rise.

The new study divides Antarctica into three regions;  West Antarctica, East Antarctica and the Antarctic Peninsula.  All three regions are losing ice, but the Western ice sheet predominates. In particular, the six huge glaciers in the Amundsen Sea Embayment are all being eroded, with the Smith Glacier surface lowering by 9 metres per year.

Professor Andy Shepherd of Leeds University said 'The peninsula is extremely rugged and previous satellite altimeters have always struggled to see its narrow glaciers. With Cryosat, we get remarkable coverage - better than anything that's been achieved before'

Comment:  Two other recent studies have focused on the melting of the Amundsen ice sheet. These increasingly accurate measurements of the rate of ice loss in Antarctica are important in understanding the future impact of global climate change.