Greenland's icecap was developing in the 1970s. Now it is losing billions of pounds every year

Greenland's ice cap melts six times faster than it was in the 1980s. And all this melting water directly raises the level of the sea.

All this, according to a new study published yesterday (April 22) in the journal Proceedings of the National Academy of Sciences, which carefully reconstructs the behavior of the ice cap in the decades leading up to the availability of modern measuring tools . Scientists already knew that there was a lot more ice in Greenland in the 1970s and 1980s. And they had specific measurements of the increase in melting since the 1990s. They now know how much things have changed dramatically over the last 46 years.

"When you look at several decades, it is better to sit in his chair before looking at the results, because it is a bit scary to see how fast that changes," Eric Rignot, a glaciologist of the University of California at Irvine, the author of the study, said in a statement. [Image Gallery: Greenland’s Melting Glaciers]

Greenland is only an island. But its ice cover has the potential to transform the entire planet. The Greenland icecap has been around for 2.4 million years and is 3.4 km thick. The whole thing weighs about half of the Earth's atmosphere, or 6 quintillions – or 6 with 18 zeros after that – pounds. (2.7 billion kilograms). If it melted entirely, the sea level would rise by 24.3 feet (7.4 meters).

In the 21st century, scientists use laser measurements of ice height, measurements of the total gravity of the ice cap and satellite photos to measure changes in ice thickness. This is so that they know that the leaf melts four times faster than in 2003, as reported by Live Science before.

To extend this recording, the researchers divided Greenland into 260 "pools" of ice, which they studied individually using a combination of direct measurements of ice changes on satellite photos. and sophisticated computer models of ice behavior. They found that between 1972 and 1980, Greenland had actually gained about 100,000 billion pounds. (47 trillion kg) of ice a year. They found that the real mass loss had begun in the 1980s. Between 1980 and 1990, the island lost about 112 trillion pounds. (51 trillion kg) of ice per year. Between 1990 and 2000, he lost about 90,000 billion pounds. (41 trillion kg) per year.

Then, in the 2000s, things accelerated considerably.

Between 2000 and 2010, Greenland lost about 412 billion pounds. (187 trillion kg) of ice per year. Between 2010 and 2018, the ice cap lost about 631 trillion pounds. (286 billion kilograms) of ice a year.

These figures translate into what researchers and inhabitants of Greenland already knew: the island is changing and its old glaciers are retreating at an alarming rate. The dramatic increase in ice loss over the last two decades coincides with a similar increase in greenhouse gases in the atmosphere and warming. As Live Science reported earlier this year, nine of the hottest 10 winters ever have occurred since 2005.

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

Originally published on Science live.