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Surge in Greenland Ice Melt Startles Scientists July 27, 2012
NASA Greenland Ice Graphic
Extent of surface melt over Greenland’s ice sheet on July 8 (left) and July 12 (right). Measurements from three satellites showed that within just a few days, the melting had dramatically accelerated from an estimated 40 percent to an estimated 97 percent.
Greenland underwent an extensive melt earlier this month that saw four days of thawing across almost all of the ice-capped island for the first time since 1889, according to NASA researchers.

Observations from three independent satellites revealed that 97 percent of Greenland’s ice cover, from its thin, low-lying coastal edges to its two-mile thick center, experienced some degree of surface melting.

Until now, the most widespread melt observed by satellites over the past 30 years was about 55 percent.

NASA says it is not clear if the sudden and brief melt was due to long-term climate change or if it will affect the overall volume of ice lost this summer.

“Ice cores from Summit (an observation point in central Greenland) 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,” said NASA Goddard glaciologist Lora Koenig.

“But if we continue to observe melting events like this in upcoming years, it will be worrisome,” Koenig added.

Greenland’s sudden melt during July was accompanied by an unprecedented melting across the Arctic that began in June. Earlier this month, an iceberg twice the size of Manhattan broke off from northern Greenland’s Petermann Glacier.

If all of Greenland’s ice were to melt, it would raise global sea levels by about 23 feet. Such a melt would take centuries even with accelerated global warming, glaciologists say.

Photo: NASA Earth Observatory