By analysing data from the Greenland GPS Network and satellite data on ice thickness, an international research team found that the Zachariae ice stream has receded by about 20 kilometres in the past decade.
‘Northeast Greenland is very cold. It used to be considered the last stable part of the Greenland ice sheet,’ said one of the study’s co-authors, Michael Bevis of Ohio State University. ‘This study shows that ice loss in the northeast is now accelerating. So, now it seems that all of the margins of the Greenland ice sheet are unstable.’
The largest ice stream in a drainage basin that covers 16 per cent of the Greenland ice sheet, Zachariae’s drainage was previously restricted by an ice-choked bay, but as the ice in the bay has retreated, the speed of the glacier has increased and more ice is being drawn down from the basin. ‘This suggests a possible positive feedback mechanism whereby retreat of the outlet glacier, in part due to warming of the air and in part due to glacier dynamics, leads to increased dynamic loss of ice upstream. This suggests that Greenland’s contribution to global sea- level rise may be even higher in the future,’ said Bevis.
This story was published in the May 2014 edition of Geographical Magazine