(Paris) The Antarctic sea ice reached last month its smallest area ever recorded for a month of July in 44 years of satellite surveys, alerted the European service on climate change Copernicus, confirming an alarming year.
Posted at 9:20 a.m.
Since 1979, scientists have had very precise measurements of the extent of the ice floes at the North and South Poles thanks to satellites. Sea ice is the ice that floats on the ocean; its melting therefore does not raise sea levels, but it indirectly contributes to global warming, as the open ocean absorbs more heat.
The normal cycle of sea ice, in the Arctic as in Antarctica, is that it melts in summer and re-forms in winter. In the long term, melting is rapid in Greenland and the Arctic, but conversely, in Antarctica, the trend was modestly increasing, despite significant annual and regional variations, without exactly understanding the phenomenon.
The Antarctic sea ice had only reformed in July, which is winter in the southern hemisphere, over an average of 15.3 million square kilometers, or 1.1 million km2 less (-7%) than the average for this month between 1991 and 2020, found the scientists of Copernicus (C3S).
At the end of the austral summer, in February, the sea ice had shrunk to its historic low, panicking scientists. It was 30% smaller than the three-decade average between 1981 and 2010. Since February, it had remained below seasonal averages, according to C3S. And in June already, it had reached its historic low for the month.
In the Arctic, the area of sea ice was 4% below average in July, according to Copernicus, or the 12e smallest extent ever recorded in July.
Illustrating the imperfect understanding of the warming phenomenon in Antarctica, Copernicus recalls that the ice pack there was, conversely, above average a year ago, in July 2021.
2022 is a year of climate records in the world. July was one of the three hottest on record in the world, according to the World Meteorological Organization (WMO), a UN specialized agency based in Geneva.