Greenland has lost nearly 3.8 trillion metric tons of ice since 1992, as ice loss accelerated from 33 billion metric tons per year in the 1990s to 254 billion tons annually in the past decade, a sevenfold increase.

These are the somber statistics coming out of a new analysis of data from 11 satellites that monitor changes in the Greenland ice sheet’s volume, flow and gravity. A metric ton is about 1.1 U.S. tons, making the number in American parlance commensurately larger.

Published Tuesday in the journal Nature, the study was an international collaboration among 89 polar scientists from 50 institutions, supported by both NASA and the European Space Agency. The Ice Sheet Mass Balance Inter-comparison Exercise drew data from 13 agency satellite missions “to create the most accurate measurements of ice loss to date,” said NASA’s Jet Propulsion Laboratory at the California Institute of Technology in a statement.

The Intergovernmental Panel on Climate Change’s 2013 central climate warming scenario predicted a 60-centimeter (about 24-inch) rise in global sea level by 2100, putting 360 million people at risk of coastal flooding every year, the University of Leeds said in a statement. In contrast, the new study tracks the panel’s high-end climate warming scenario, which predicts 3 inches more, the Leeds statement said.

The 3.8 trillion tons of melted ice is equivalent to emptying 120 million Olympic-size swimming pools to the ocean annually for 26 years, NASA said, increasing sea level by 11 millimeters, or nearly half an inch.

“As a rule of thumb, for every centimeter rise in global sea level, another 6 million people are exposed to coastal flooding around the planet,” said Andrew Shepherd, lead author and scientist from the University of Leeds in the United Kingdom, in a statement from NASA. “On current trends, Greenland ice melting will cause 100 million people to be flooded each year by the end of the century, so 400 million in total due to sea level rise.”

This report comes out as world leaders and activists converge in Madrid at COP25, the United Nations Climate Change conference, from Dec. 2-13.

It could be yet another classic tipping point.

“Satellite observations show that the Greenland ice sheet has reacted rapidly to environmental change by losing mass,” said the ESA’s Marcus Engdahl, one of the paper’s co-authors. “This is especially worrying as the global mean sea-level rise caused by the melting ice sheet is irreversible in human or societal time scales.”

“These are not unlikely events or small impacts,” Shepherd emphasized in the ESA statement. “They are happening and will be devastating for coastal communities.”

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