"Extraordinary" Greenland ice sheet melt surprises scientists



Posted on 25 July 2012  | 
For the first time in 30 years of satellite monitoring, nearly all of Greenland's ice sheet is thawing. NASA reports that 97% of the ice sheet, even the two-mile-thick centre, experienced some surface melting - an event so unusual that researchers initially suspected a data error. On average, only half of the ice sheet experiences melting in the summer.

This news comes as WWF staff and researchers are travelling up the coast of Greenland to explore the "Last Ice Area", the region in northern Greenland and Canada where sea ice is projected to last the longest in a warming Arctic. Over the next six weeks, researchers will assess the changing wetlands on Greenland's coast, verify satellite measurements of ice, and study the marine microbiology of the high Arctic.

Video: The crew of the Last Ice Area voyage encounter ice calved from Ilulissat's glacier:


The researchers say that this unusual event, like the enormous iceberg calved from the Petermann glacier last week, is part of a complex story. "Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," researcher Lora Koenig said. "But if we continue to observe melting events like this in upcoming years, it will be worrisome."
Extent of surface melt over Greenland’s ice sheet on July 8 2012(left) and July 12 2012(right). Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12.
© NASA Enlarge
"Depending on how melting will evolve in August, the 2012 melting season might set a new melting record. Nevertheless, 2012 is already positioning among the top melting years, with the cumulative melting index until July 25th being close to the cumulative melting index for the whole 2010 and higher than the one for the 2011 season." - Marco Tedesco
© M Tedesco/WWF Enlarge

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