Greenland's Ice Sheet Has Been Melting Much Faster than Originally Believed.
Greenland's ice sheet melted more last year than any year previously recorded, according to a new study, in another sign of the devastating impacts of a warming planet.
The research, published in the journal Communications Earth and Environment on thursday, found that in 2019 Greenland's ice sheet lost an annual record of 532 billion tons of ice, with 223 billion tons of ice lost during the month of July alone.
To put that in comparison, between 2003 and 2016 the ice sheet lost about 255 billion tons of ice on average -- per year.
"We have documented another record loss year for Greenland," said Ingo Sasgen, a glaciologist at the Alfred Wegener Institute for Polar and Marine Research and co-author of the study.
"What this shows is that the ice sheet is not only out of balance but it's increasingly likely to produce more and more extreme loss years."
The report follows another study published last week that found Greenland's ice sheet has melted to a point of no return, and is retreating in rapid bursts, leading to a sudden and unpredictable rise in sea levels.
Greenland, an autonomous territory of Denmark, is the world's largest island. It's located between the Arctic and Atlantic oceans, east of Canada's Arctic Archipelago. Around 79% of its surface is covered in ice.
Greenland's ice sheet is the second biggest in the world behind Antarctica's, and its annual ice melt during summer contributes more than a millimeter rise to sea levels every year.
But that's set to get worse as increasing greenhouse gas emissions continue to warm the planet.
"We see an Arctic warming about one and a half times faster in summer compared to the global average," Sasgen said.
In 2019, Greenland's ice sheet lost 15% more ice than the previous record set in 2012, the study found. And while the ice sheet has been increasingly melting since the 1990s, according to the report, several conditions led to the record melt in 2019.
Sasgen said that these ever-increasing temperatures combined with a low snowfall, and warm atmospheric and cloud-free conditions that allowed more solar radiation to enter the ice sheet, led to the huge melt production seen last year.
Interestingly, two colder years that preceded 2019 saw a reduction in the ice melt. Satellite data found that Greenland's ice loss in 2017 and 2018 was lower than in any other two-year period between 2003 and 2019, due to two abnormally cold summers in western Greenland, a snowier fall and winter conditions in the east, according to the report.
However, Sasgen said those two cold years don't compensate for the dramatic melting in 2019. The report found that the ice sheet will continue to lose mass in response to Arctic warming.
"This extreme melt kicks off feedbacks that may accelerate the mass loss. This is what is worrying, the extremes are increasing and we understand too little about how the ice sheet will respond to more extreme climate variability," Sasgen said.
Sea levels are projected to rise by about 1 meter (3 feet) by the end of the century, inundating low-lying coastal areas and wiping away beaches and properties. Without building up defenses, some 300 million people worldwide -- including in the United States, Europe and across Asia -- could be at risk of losing their homes to rising seas over the next three decades, by some projections.
From coastal US states such as Florida, major global cities like London, Shanghai, and Hong Kong, to low-lying big cities like Bangladesh's Dhaka or India's Kolkata and entire Pacific islands are all at risk from rising sea levels.
Reducing CO2 levels, Sasgen said, is the only hope to slow global warming and reduce future extreme ice melt.
Like we think of the Romans as the civilization who invented the sewer system, Sasgen said we should consider how our society will be thought of in years to come.
"If you think about our civilization in 2,000 years when the ice sheet has significantly shrunk and the sea level has risen by probably a few meters, our society will be regarded as the one that triggered this decrease in continental ice," he said.
"It's not only four years, or 10 years or 100 years, it's a process that will continue for a very long time and we're just seeing the start of it."