East Antarctica experienced unusually high temperatures, more than 30°C above normal, last week.
The Concordia research base, located on Dome C of the Antarctic plateau at an altitude of more than 3,000 m, thus recorded last Friday a record "heat" of -11.5 ° C.
The Russian station of Vostok recorded temperatures climbing to -17.7°C, while in March, the thermometer there was closer to -40°C.
“What is striking about this episode of heat in Antarctica is that it is happening in a place where it had never been observed.
This is what is really amazing, ”explains Gaétan Heymes, meteorologist at Météo France, who spent almost a year in Antarctica in 2019.
While temperatures should have dropped with the onset of the austral winter, the Dumont d'Urville base, located on the coast of Terre-Adélie, east of Antarctica, also set a mildness record. for the month of March, with +4.9°C, and a record minimum temperature of +0.2°C on March 18.
Particularly mild temperatures which are explained, according to Gaétan Heymes, of Météo France, by the presence of an "atmospheric river": "It is a transfer of high concentrations of water vapor into the atmosphere, from the Australia, New Zealand, to Antarctica”.
With this strong water vapour, which is warmer, precipitation increases, in a region which is normally "an ice desert", recalls the specialist.
“Atmospheric rivers are phenomena that happen, but they had never been observed at this intensity”.
The poles are warming even faster than the planet's average, which has gained on average about +1.1°C since the pre-industrial era.
This heat wave in eastern Antarctica comes as the end of February the Antarctic sea ice had reached its smallest area recorded since the beginning of satellite measurements in 1979, with less than 2 million km2, according to the American research center National Snow and Ice Data Center.
Although it is not possible at the precise moment an event occurs to attribute it to climate change, one of the clearest signs of global warming is the multiplication and intensification of heat waves.
“The impact of this episode on climatologists and meteorologists is of the same magnitude as what happened in Canada and the United States last year.
But these events occurred in places where the climate was known to be changing.
But there, in Antarctica, a new signal is being sent and no place on the globe seems to be spared", believes Gaétan Heymes, while trying to be reassuring: "we must not enter into catastrophism and think that this kind of event will repeat every year, but it's a bit of a warning”.