‘Devastating’ melting of Greenland, Antarctic ice sheets found

A new comprehensive international study reveals that the ice sheets of Greenland and Antarctica are now losing more than three times as much ice as they were 30 years ago.

Using 50 different satellite estimates, the researchers found this Greenland melt I got into hyperdrive the last few years. Greenland’s average annual melt from 2017 to 2020 was 20% more annually than it was at the start of the decade and more than seven times the annual contraction in the early 1990s.

Study co-author Ruth Mottram, a climate scientist at the Danish Meteorological Institute, said the new figures were “truly catastrophic”. “We are losing more and more ice from Greenland.”

The study’s lead author, Ines Otosaka, a glaciologist at the University of Leeds in the United Kingdom, said the rapid loss of the ice sheet is clearly caused by Man-made climate change.

From 1992 to 1996, the two ice sheets–which contain 99% of the world’s freshwater ice–were shrinking by 116 billion tons (105 billion metric tons) annually, two-thirds of it from Antarctica.

But from 2017 to 2020, the most recent data available, combined melt has risen to 410 billion tons (372 billion metric tons) annually, more than two-thirds of which is from Greenland, the study reported in Thursday’s Journal. Earth System Science Data.

“This is a devastating trajectory,” said Twyla Moon, vice president of the US National Snow and Ice Center, who was not part of the study. “These rates of ice loss are unprecedented during modern civilization.”

The study found that since 1992, Earth has lost 8.3 trillion tons (7.6 trillion metric tons) of ice from the two ice sheets. That’s enough to flood the entire United States with 33.6 inches (about 0.9 meters) of water or flood France in 49 feet (about 15 meters).

But because the world’s oceans are so huge, melting from ice sheets since 1992 still only adds less than an inch (21 millimeters) of sea level rise, on average. globally Sea level rise is accelerating The study said melting from ice sheets has gone from contributing 5% to sea level rise to now accounting for more than a quarter of it. The rest of the sea rise comes from the expansion and melting of warm water from glaciers.

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a A team of over 65 scientists It regularly calculates ice sheet loss in research funded by NASA and the European Space Agency, with Thursday’s study adding another three years of data. They’re using 17 different satellite missions and examining the melting of the ice sheet with three distinct technologies, Otosaka said, and all the satellites, radar, observations on the ground, and computer simulations are saying the same thing — the melting of the ice sheet is accelerating.

Greenland averaged from 2017 to 2020 about 283 billion tons (257 billion metric tons) of melt per year, compared to just 235 billion tons (213 billion metric tons) per year from 2012 to 2016.

The latest figures also showed what appears to be a slowdown in melting in parts of Antarctica, which has much more ice than Greenland. This is mostly due to smaller, more transient climate changes, Mottram said, and the overall long-term trend continues to show an acceleration of melting in Antarctica.

From 2017 to 2020 Antarctica is still losing about 127 billion tons (115 billion metric tons) of ice annually, down 23% from earlier this decade, but overall down 64% since the early 1990s.

“While mass loss from Greenland outpaces that from Antarctica, there are disturbing wild leaves to the south, particularly the behavior of the Thwaites Glacier,” Nicknamed Doomsday Glacier, said Mark Serris, director of the American Snow and Ice Center, who was not part of the study.

Using changes in gravity and ice height, the study authors measured how much snow fell, how much snow melted, and how much ice was lost in icebergs that were being generated and devoured by the warm water that burrowed into the ice.

“This is important because rising sea levels will displace and/or financially impact hundreds of millions of people, if not billions, and likely cost trillions of dollars,” said University of Colorado ice researcher and former NASA chief scientist Walid Abdel-Aty, who was not t is part of the study.

“The study is not as surprising as it is disturbing,” Abdel-Aty said in an email. “A few decades ago, it was assumed that these vast ice reservoirs changed slowly, but through the use of satellites, field observations, and modeling techniques, we have learned that ice It responds quickly to our changing climate.”

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