Thaw in Antarctica | In just three years, I lost …

After decades of expansion, an American study has quantified the vertiginous speed of Antarctic icecover reduction since 2014, a year that marked a turning point for this continent.

"In just three years, the Antarctic has lost as much ice as the Arctic," said Claire Parkinson, climate scientist at NASA, who published in the archives of the American Academy of Science (PNAS) a study badyzing changes in the Antarctic ice mbad from 1979 to 2018.

Scientists already knew that Antarctica was melting faster and faster, just like the Arctic, because of the increasing spill of glacier water.

But for decades, they have observed a phenomenon both rebaduring and intriguing: the surface of the ice cap, that is to say the thick layer of ice floating in the ocean, was growing .

Parkinson, NASA's Goddard Space Center, near Washington, reconstructed between 1979 and 2018 the most accurate history of this Antarctic sea ice. but only the extension. The scientist published this reference data in the journal Proceedings of the National Academy of Sciences, PNAS.

The icecap melted in summer (January-March) and re-established in winter (July-September). But over time, it has tended to grow in all seasons. But something mysterious happened after 2014. From this moment, there is less and less ice floe each year.

In 2014, the Antarctic Ice Sheet was at its highest level ever recorded for these data. In 2017, it touched a minimum. The loss amounts to two million square kilometers, a little more than the surface of Mexico. And the trend seems to continue in 2019, adds the climatologist.

Scientists do not know why the ice has been growing for so long, or why it is melting today.

Several hypotheses take into account the hole in the ozone layer, the winds, the currents or the temperature of the deep waters, but no one explains with certainty the change of 2014. "In my opinion, no hypothesis n & rsquo; Is correct, "he said. Douglas Martinson, oceanographer at Columbia University, participated in the peer review committee that validated the article.

The scientist warns that comparing the Arctic to the Antarctic is equivalent to "comparing apples to military trucks". The Arctic is an ocean surrounded by land, while Antarctica is a continent surrounded by oceans, where the pressure of icebergs is lesser.

Antarctica does not warm up and remains the coldest place on the planet and its largest fresh water supply. Its ice mountains contain a volume capable of raising the sea level by 57 meters, according to a study conducted in 2013.

Chris Rapley, a climatologist at University College London, points out that the initial gains in ice before 2014 did not contradict global warming.

"It only shows that in a complex and interconnected system, counter-intuitive things can happen, at least for a while," the researcher wrote. "We tend to look for simplistic explanations of the causes and effects, but in reality, the situation is much more complex and nuanced," he concludes.