"Greenland ice sheet melted at unprecedented rate during July"

From the Guardian.UK:
"Scientists at Nasa admitted they thought satellite readings were a mistake after images showed 97% surface melt over four days"

The Greenland ice sheet on July 8, left, and four days later on the right. In the image, the areas classified as 'probable melt' (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as 'melt' (dark pink) correspond to sites where two or three satellites detected surface melting. Photograph: Nasa

The Greenland ice sheet melted at a faster rate this month than at any other time in recorded history, with virtually the entire ice sheet showing signs of thaw.

The rapid melting over just four days was captured by three satellites. It has stunned and alarmed scientists, and deepened fears about the pace and future consequences of climate change....

The set of images released by Nasa on Tuesday show a rapid thaw between 8 July and 12 July. Within that four-day period, measurements from three satellites showed a swift expansion of the area of melting ice, from about 40% of the ice sheet surface to 97%.

Scientists attributed the sudden melt to a heat dome, or a burst of unusually warm air, which hovered over Greenland from 8 July until 16 July.

Greenland had returned to more typical summer conditions by 21 or 22 July, Mote told the Guardian.

But he said the event, while exceptional, should be viewed alongside other compelling evidence of climate change, including on the ground in Greenland.

"What we are seeing at the highest elevations may be a sort of sign of what is going on across the ice sheet," he said. "At lower elevations on the ice sheet, we are seeing earlier melting, melting later in the
season, and more frequent melting over the last 30 years and that is consistent of what you would expect with a warming climate."

Zwally, who has made almost yearly trips to the Greenland ice sheet for more than three decades, said he had never seen such a rapid melt.

About half of Greenland's surface ice sheet melts during a typical summer, but Zwally said he and other scientists had been recording an acceleration of that melting process over the last few decades. This year his team had to rebuild their camp, at Swiss Station, when the snow and ice supports melted.

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