Greenland is about one-quarter as big as the continental United States, and 80 percent of it is covered by a massive ice sheet. It got its name because, from about A.D. 1000 to 1300, during the so-called “Medieval Warm Period,” it was warm enough to support forests and thriving colonies of Viking settlers.

This year’s melt lifted global sea levels by about two one-hundredths of an inch, Steffen said. If the entire ice cap melted, it could raise the sea by 21 feet, swamping coastal cities and low-lying islands, but such a catastrophe isn’t expected for at least a thousand years, if ever.

Steffen, who’s spent 18 seasons working on the Greenland ice cap, attributed the accelerated melting to an air temperature increase of about 7 degrees Fahrenheit since 1991.

Ten percent more ice melted this year than in 2005, the previous record year. Since 1979, when satellite data over Greenland began, melting has increased by a total of 30 percent, he said.

Konrad Steffen is an arctic expert at the University of Colorado in Boulder. Read more here.

An iceberg calved from the massive Jacobshavn glacier shows how Greenland is losing ice at a record rate. pic courtesy of propeller.com.