Dangerous melting of the Greenland ice sheet

A portion of the Greenland ice sheet appears to be reaching a tipping point where it would fall into an irreversible period of melting, according to research by the Potsdam Institute for Climate Impact Research.  The ice covers about 660,000 square miles and is up to 3,000 m thick.  It will retain its size only if the mass lost to meltwater and calving icebergs each year is replenished by new snowfall.  The research suggests that warming of the Arctic has disturbed this balance.  The ice sheet is shrinking.  As its height reduces, it is exposed to higher average temperatures.  This leads to more melting, further height reductions, warmer temperatures still and an accelerating loss of ice.  The collapse of the sheet, which contains enough ice to raise global sea levels by 7 metres, would affect coastal regions and cities around the world.
Proceedings of the National Academy of Sciences of the USA
Guardian, 17 May 2021