Rain melting Greenland ice sheet ‘even in winter’
Rain is becoming more frequent in Greenland and accelerating the melting of its ice, a new study has found. Scientists say they’re “surprised” to discover rain falling even during the long Arctic winter. The massive Greenland ice-sheet is being watched closely because it holds a huge store of frozen water.
Precipitation usually falls as snow in winter – rather than as rain – which can balance out any melting of the ice in the summer. Even if it falls during winter, and then quickly refreezes, the rain changes the characteristics of the surface, leaving it smoother and darker, and “pre-conditioned” to melt more rapidly when summer arrives.
The darker the ice is, the more heat it absorbs from the Sun – causing it to melt more quickly.
Whereas in 1979 there were on average 2 spells of winter rain, by 2012 the analysis found there were 12 spells of winter rain.
In stable times, snowfall in winter will balance any ice melted or breaking off into the ocean in summer. But research has shown how in recent decades the ice-sheet has been losing vast amounts of mass.