World’s Fastest Moving Glacier Found In Greenland
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Lee Rannals for redOrbit.com – Your Universe Online
Researchers from the University of Washington and the German Space Agency (DLR) say that a Greenland glacier is slipping off into the ocean at a speed never before seen.
The scientists measured the speeds of Jakobshavn Isbræ (Jakobshavn Glacier) in Greenland and found that this glacier is the fastest moving ice sheet ever recorded.
“We 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,” Ian Joughin, a researcher at the Polar Science Center, University of Washington and lead-author of the study published in The Cryosphere, said in a statement.
The researchers used satellite data to measure Jakobshavn Isbræ’s speed as part of the US National Science Foundation (NSF) and NASA studies. They said they used computers to compare pairs of images taken by the DLR TerraSAR-X satellites.
“As the glacier moves we can track changes between images to produce maps of the ice flow velocity,” says Joughin.
The team said the glacier reached a speed of more than 10 miles per year, setting a record for the fastest glacier or ice stream in Greenland or Antarctica. They said summer speeds are temporary, with the glacier flowing slower over the winter months. However, the annually average speed over the past couple of years is three times what it was in the 1990s.
“We know that from 2000 to 2010 this glacier alone increased sea level by about 1 mm (0.03-inch). With the additional speed it likely will contribute a bit more than this over the next decade,” explains Joughin.
Jakobshavn Isbræ drains the Greenland ice sheet into a deep ocean fjord on the coast of the island. Some of the ice melts from the glacier, while the rest is pushed out, floating farther out into the ocean. These processes help contribute to the same amount of sea-level rise from Greenland.
Greenland glaciers have been thinning and calving icebergs farther and farther inland over the years as global warming takes its toll on the northern environment. The scientists said that the front of the glacier retreated more than a half mile farther inland than previous summers. They say the thinning and retreat of this glacier is due to its increase in speed.
“As the glacier’s calving front retreats into deeper regions, it loses ice – the ice in front that is holding back the flow – causing it to speed up,” Joughin said.
Jakobshavn Isbræ is believed to be the glacier responsible for sinking the Titanic back in 1912. The researchers say this glacier will continue to retreat farther inland, and by the end of the century its calving front could retreat as far back as the head of the fjord.