High ice melt in Greenland causes concern

An exceptionally high rate of melt on the surface of Greenland’s ice cap in 2012 is causing concern among climate scientists, according to a report from the National Snow and Ice Data Center, or NSIDC. Apparently satellite surveillance of the ice cap indicated rates of surface melting far in excess of melting observed in previous years, since satellite observations began in 1979.

In particular, following an exceptional weather event in July 2012, surface melting took place over 97 percent of the entire ice sheet, NSIDC says.

The melting of land-based ice such as is found in Greenland, as distinct from the melting of floating sea ice, is of particular significance because the unlocking of huge quantities of freshwater locked up in ice supported on land would directly cause a rise in worldwide sea levels.

A large-scale melt of the Greenland ice cap could raise sea levels sufficiently to flood many coastal areas where people live around the world, NSIDC says.

“The ice sheet normally gains snow during the winter and melts some during the summer, but in recent decades its mass has been dwindling due to strong melting,” NSIDC says.

Because of persistent high atmospheric pressure and clear skies during the summer of 2012, temperatures between June and August were more than 4 degrees F higher than average in areas of Greenland normally susceptible to summer ice melt, and more than 3 degrees F higher than average across the entire ice cap.

And, as further evidence of accelerated melting, zones exhibiting different snow and ice features characteristic of the summer melt have been moving to higher elevations on the ice sheet. In 2012 there was unprecedented melting at the highest elevations of the ice.

—Alan Bailey