Melting Greenland ice sheet increases sea level
Additional three million tonnes of water streaming into oceans daily, contributes 40% to rise
Paris, Aug. 21: Greenland’s massive ice sheet saw a record net loss of 532 billion tonnes last year, raising red flags about accelerating sea level rise, according to new findings.
That is equivalent to an additional three million tonnes of water streaming into global oceans every day, or six Olympic pools every second.
Crumbling glaciers and torrents of melt-water slicing through Greenland’s ice block — as thick as ten Eiffel Towers end-to-end — were the single biggest source of global sea level rise in 2019 and accounted for 40 per cent of the total, researchers reported in the journal communications earth and environment.
Last year’s loss of mass was at least 15 per cent above the previous record in 2012, but even more alarming are the longterm trends, they said.
“2019 and the four other record-loss years have all occurred in the last decade,” lead author Ingo Sasgen, a glaciologist at the Helmholtze Centre for
Polar and Marine Research in Germany, said.
The ice sheet is now tracking the worst-case global warming scenario of the UN’s climate science advisory panel, the IPCC, noted Andrew Shepherd, director of the Centre for Polar Observation and Modelling at the University of Leeds.
“This means we need to prepare for an extra ten centimetres or so of global sea level rise by 2,100 from Greenland alone,” said Shepherd, who was not involved in the study.
If all of Greenland’s ice sheet were to melt, it would lift global oceans by seven metres.
Even a more modest rise of a couple of metres would redraw the world’s coastlines and render land occupied today by hundreds of millions of people uninhabitable.
Until 2000, Greenland’s ice sheet—covering an area three times the size of France—generally accumulated as much mass as it shed. Runoff, in other words, was compensated by fresh snowfall. But over the last two decades ago, the gathering pace of global warming has upended this balance.
The gap is widening at both ends, according to the study, which draws from nearly 20 years of satellite data.
Changing weather patterns — also a consequence of climate change — has resulted in less cloud cover, and thus less snow. These high pressure systems have also resulted in more, and warmer, sunny days, accelerating the loss of mass.