While a global day of youth action for the climate is organized this Friday, March 25 all over the world, an event came to remind us of the reality of climate change: record temperatures for the season were recorded simultaneously at the two poles at the end of last week. On Thursday March 17 and Friday March 18, temperatures exceeded seasonal norms by more than 40°C in Antarctica, and variations of more than 30°C were also observed in the Arctic. This visualization from the Institute on Climate Change at the University of Maine (USA) shows the extent of these two simultaneous waves of mildness on both poles.
Remarkable extreme events ongoing in both the #Arctic and #Antarctic the last few days – related to the poleward transport of heat+moisture (separately)
[Graphic from https://t.co/53SpSZcJCa] pic.twitter.com/qHU0u9HLt0
—Zack Labe (@ZLabe) March 19, 2022
Supporting infographics, franceinfo comes back to these exceptional heat waves and what they say about the state of the polar climates. While the records recorded in Antarctica surprised by their magnitude and suddenness, the wave of mildness at the North Pole is on the contrary the syndrome of a warming that has been going on for many years.
In Antarctica, an unprecedented phenomenon that worries
“This is unheard of ! We are 40°C above seasonal norms, but also nearly 15°C above previous records for the seasonsays Gaétan Heymesforecasting engineer at Météo France. Even if in Antarctica the climate is more changeable than in France, the temperature difference could be compared to a heat of 35°C in March in Paris“explains the man who spent several weeks on a mission to the South Pole.
The temperatures recorded at the Franco-Italian base Concordia, located in Antarctica, are indeed impressive. The following graph is produced using data provided by the Observatoire de la Côte d’Azur and based on the model of an infographic made by the latter. It allows you to realize that the -12°C measured on March 18 is an all-time high for at least eight years, and that this peak comes at a time of year when temperatures are generally falling. Normally, they are around -55°C.
Tristan Guillot was in the front row to observe this record. At the Côte d’Azur Observatory, where he is CNRS research director, researchers receive live images from the Concordia base and operate a telescope on site. But on March 17, an event came to disrupt the operation of the device: “We received a message from a person wintering on site informing us of abnormal heating of the camera box of our telescope, heated to withstand outside temperatures of -80°C. We then noticed that the temperature in the camera box exceeded 40°C! We have been forced to halt our telescope acquisitions while waiting for more normal conditions.”
If this temperature particularly surprised the scientists, cis because it intervenes in a region that did not seem to be in a warming dynamic: “In Antarctica, an increase in temperatures was observed in the west, but not in the east of the continent, while it is precisely in this area that the heat wave was recorded.details Gaétan Heymes. As this event is exceptional and is not part of a long-term dynamic, it is difficult to attribute it with certainty to climate change today. But it is very likely that with hindsight, the link will be demonstrated“, affirmshe.
An alert on the situation in Antarctica had already been registered last month. In February 25, in the middle of the austral summer, the surface of the pack ice around the white continent had reached its historic low for more than forty years that it is measured. But once again, as the phenomenon is not long-lasting for the moment, it is difficult to make a direct link with climate change.
In the Arctic, a warming observed for several years
At the same time, the Arctic, although immersed in the boreal winter, also recorded very high temperatures, more than 30°C above normal for the season. But unlike the South Pole, the rise in temperatures in the Arctic is part of a strong warming of the region observed for several years.
“The heat wave at the North Pole is slightly smaller than at the South Pole, but above all it is less surprising because the rapid warming of the North Pole is a well-known phenomenon” Explain Gaetan Heymes. Indeed, the Arctic is warming much faster than the rest of the globe: atWhile the global temperature has increased by about 1°C compared to the reference period 1950-1980, this increase reaches almost 3°C for the Arctic.
This accelerated warming is the result of a vicious circle in which the North Pole region finds itself: “IRising temperatures melt the ice, and as ice normally reflects the sun’s rays, its disappearance leads to greater absorption of this solar heat, and therefore a rise in temperatures.“explains Joël Guiot, director of research at the European Center for Research and Education in Environmental Geosciences.
The melting of sea ice (pack ice) in summer in the North Pole region has been very marked for the past fifteen years: while the minimum sea ice surface (that reached at the end of the summer) never fell below 6 million square kilometers until the end of the 1990s, this annual minimum surface is barely more than 4 .5 million square kilometers on average since the mid-2000s. The fifteen lowest levels recorded since the beginning of the 1980s correspond to the last fifteen years.
According to Patricia Espinosa, executive secretary of the United Nations Framework Convention on Climate Change (UNFCCC), Arctic Ocean summers could be ice-free as early as 2030 if CO2 emissions continue at current rates.