Although the fact that the surface of Greenland's massive ice
sheet is melting is not news, the size and speed of the melt is.
NASA scientists say a melt has taken place over a larger area
than has been detected in three decades of satellite
observation. Greenland's ice sheet is losing more ice than it
gains, a loss that measures about 150 gigatons of ice each year.
Such losses will have an effect on the level of the sea,
contributing to a rise in sea level of about 3-4 millimeters per
year. Dorothy Hall is a senior research scientist at NASA.