Greenland ice sheet lost a record 1m tonnes of ice per minute in 201

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https://www.theguardian.com/environment/2020/aug/20/greenland-ice-sheet-lost-a-record-1m-tonnes-of-ice-per-minute-in-2019

Greenland ice sheet lost a record 1m tonnes of ice per minute in 2019

Damian Carrington Environment editor

Thu 20 Aug 2020 16.00 BSTLast modified on Thu 20 Aug 2020 16.42 BST

The Greenland ice sheet lost a record amount of ice in 2019, equivalent to a million tonnes per minute across the year, satellite data shows.

The climate crisis is heating the Arctic at double the rate in lower latitudes, and the ice cap is the biggest single contributor to sea level rise, which already imperils coasts around the world. The ice sheet shrank by 532bn tonnes last year as its surface melted and glaciers fell into the ocean and would have filled seven Olympic-sized swimming pools per second.

The satellite data has been collected since 2003. The 2019 loss was double the annual average since then of 255bn tonnes. Almost that amount was lost in July 2019 alone.

Scientists knew that ice loss from Greenland had been accelerating fast in recent decades and that there had been high rates of melting in 2019. But the satellite data accounts for new snowfall and allows the net loss to be calculated. The researchers said the scale of the 2019 loss was shocking and was likely to be the biggest in centuries or even millennia.
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The scientists attributed the extreme ice loss in 2019 to “blocking patterns” of weather that kept warm air over Greenland for longer periods. These are becoming increasingly frequent as the world heats up. Almost 96% of the ice sheet underwent melting at some point in 2019, compared with an average of 64% between 1981 and 2010.
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Snowfall in Greenland was low in 2019, also due to the blocking pattern, meaning relatively little new ice was added. “The real message is that the ice sheet is strongly out of balance,” Sasgen said.
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Weather data and computer models allow for losses to be calculated back to 1948. “If we look at the record melt years, the top five occurred in the last 10 years, and that is a concern. But we know what to do about it: reduce CO2 emissions.”

Sasgen said a further worry was feedback mechanisms that increase ice loss, including meltwater weakening the ice sheet and speeding its fall into the ocean. Hotter weather also melts the white snow on top of the sheet, revealing darker ice below, which absorbs more of the sun’s heat.

“These results come at a crucial time,” said Yara Mohajerani, of the University of California Irvine in the US, who was not part of the study team. “2019 broke the previous record of 2012 by 15%, itself an unmatched record over the past several centuries to millennia.”
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