Greenland’s Ice Sheet Was Growing. Now It’s in a Terrifying Decline

By Rafi Letzter, Live Science

Greenland’s ice sheet is melting six times faster than it was in the 1980s. And all that meltwater is directly raising sea levels.

That’s all according to a new study, published April 22 in the journal Proceedings of the National Academy of Sciences, that carefully reconstructs the behavior of the ice sheet in the decades before modern measurement tools became available. Scientists already knew that there was a lot more ice on Greenland in the 1970s and 1980s. And they’ve had precise measurements of the increase in melting since the 1990s. Now they know just how dramatically things have changed in the last 46 years.

“When you look at several decades, it is best to sit back in your chair before looking at the results, because it is a bit scary to see how fast it is changing,” University of California, Irvine, glaciologist Eric Rignot, a co-author of the study, said in a statement.

Greenland is just one island. But its ice sheet has the potential to transform the entire planet. The Greenland ice sheet has existed for 2.4 million years and is 2.1 miles (3.4 kilometers) thick at its deepest point. The whole thing weighs about half as much as Earth’s whole atmosphere, or 6 quintillion — or 6 with 18 zeros after it — lbs. (2.7 quintillion kilograms). If it melted entirely, sea levels would rise by 24.3 feet (7.4 meters).

Between 2000 and 2010, Greenland lost about 412 trillion lbs. (187 trillion kg) of ice per year. Between 2010 and 2018, the ice sheet lost roughly 631 trillion lbs. (286 trillion kilograms) of ice per year.

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Those numbers make concrete what researchers and inhabitants of Greenland already knew: that the island is changing and its ancient glaciers are receding at an alarming rate. The dramatic uptick in ice loss in the last two decades coincides with a similar surge in atmospheric greenhouse gases and warming. As Live Science reported earlier this year, nine of the 10 warmest winters on record have happened since 2005.

What does this all mean for the future of the ice sheet, as well as global sea levels? As the Intergovernmental Panel on Climate Change concluded, that will depend primarily on what humans do next.