Satellite data suggest that part of the Greenland ice sheet moves more slowly if the surface of the ice melts faster.
Greenland is losing vast quantities of ice to the ocean, raising sea levels. Icebergs calving from the edge of the ice sheet account for around half of this loss and the other half is because of surface melt. The Greenland ice sheet is always on the move, flowing under its own weight. By tracking the movement of stable features such as crevasses in satellite images taken every year from 1985 to 2014, they mapped annual ice speed and compared it with meltwater produced on the surface.
Andrew Tedstone from the University of Edinburgh said, “Our investigations suggest that the efficiency of these drainage systems is greater after summers of stronger melting.
“The melting actually reduces the lubrication at the ice sheet base during the following winter – causing winter ice flow to be slower after a warmer summer.
“The results show that since 2002, the flow of an 8000 sq km land-terminating sector of the Greenland ice sheet has slowed down despite an increase in surface melting.”