The surface of sea ice from the South Pole is the lowest ever recorded since the start of satellite surveys in 1979. Enough to worsen the climatic disruption of the region and the debacle of the ice cap.
by Audrey Garric
This is an extreme situation. The Antarctic Banquise broke a cast iron record, even before the end of the southern summer. It fell to 1.91 million km 2 on Monday, February 13, the lowest extent ever recorded since the start of satellite surveys, in 1979, according to the center US national data on snow and ice (NSIDC) . This narrowing continues to worsen Day after day, while the sea ice of the South Pole only reaches its annual minimum only around the end of February-beginning March.
“We are perhaps changing in a regime where the Antarctic pack ice is no longer immune to climate change”, warns François Massonnet, climatologist at the Catholic University of Louvain (Belgium). More broadly, it is the whole white continent, that we believed, several decades ago, to be able to resist the assaults of greenhouse gas emissions, which gives signs of vulnerability.
The Antarctic Banquise, which knows its minimum extent in February-March each year before growing until maximum mid-September, is subject to high annual variability. However, it experienced an expansion between the years 2005 and 2015, frequently exceeding 3.5 million km 2 at the height of summer melting.
“Marine heat wave Extraordinary “
This phenomenon remained a mystery for scientists while in parallel, the Arctic ice floe never ceased to disappear more year after year, under the effect of warming. But the year 2016 marked a reversal of the situation. Since then, at all seasons, the sea ice from the South Pole has recorded abnormally low areas. Before this year, the previous minimum extent records dated 2022 and 2017.
Failing systematic statements in a highly inhospitable region, scientists are reduced to conjectures. Western winds stronger than the average have brought hot air on both sides of the Antarctic Peninsula. “But that does not explain the very low area recorded in all of the basins,” notes François Massonnet. He hypothesizes that a warming of the oceans melted under its surface. “It should be confirmed and to find out if it is linked to greenhouse gas emissions,” he said.
Scientist Carlos Moffat, of the University of Delaware, in the United States, recently returned from a research cruise in the Southern Ocean, evokes an “extraordinary marine heat wave”. “Even if I observe these changing systems for a few decades, I was surprised by the degree of warming that I noticed,” he told the site Inside Climate News . In 2022, eastern Antarctica had experienced an unprecedented episode of heat, this time air, with temperatures up to 40 ° C greater than seasonal normal.
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