Jakobshavn Isbrae (Jakobshavn Glacier) is moving ice from the Greenland ice sheet into the ocean at a speed that seems to be the fastest ever recorded, suggest researchers.
Lead author Ian Joughin, a researcher at the Polar Science Center, University of Washington, said that they are now seeing summer speeds more than 4 times what they were in the 1990s on a glacier which at that time was believed to be one of the fastest, if not the fastest, glacier in Greenland.
In the summer of 2012 the glacier reached a record speed of more than 17 kilometers per year, or over 46 meters per day.
According to the researchers, these flow rates are unprecedented: they appear to be the fastest ever recorded for any glacier or ice stream in Greenland or Antarctica.
They note that summer speeds are temporary, with the glacier flowing more slowly over the winter months. But they add that even the annually averaged speedup over the past couple of years is nearly 3 times what it was in the 1990s.
This speedup of Jakobshavn Isbrae means that the glacier is adding more and more ice to the ocean, contributing to sea-level rise. "We know that from 2000 to 2010 this glacier alone increased sea level by about 1 mm. With the additional speed it likely will contribute a bit more than this over the next decade," explains Joughin.
The team used satellite data to measure the speed of the glacier as part of US National Science Foundation (NSF) and NASA studies.
The results have been published in The Cryosphere.