When -37 degrees Celsius is considered heat | Polarjournal
Sunsets at South Pole Station announce the coming winter with darkness and low temperatures. But due to hot spells, these are often far above average for days and days. Image: Tim Lynch, National Science Foundation

While spring is slowly setting in in the northern hemisphere and the days are getting longer and longer, the long winter is setting in at the south pole. This means even lower temperatures in addition to the usual polar night. But for years, scientists have repeatedly reported unusual warm spells lasting several days. And this year is no different, but still unusual.

Since March 25, the Amundsen-Scott station at the South Pole has reported temperatures nearly 20 degrees above the long-term average. Italian journalist and expert on the subject Stefano Di Battista tweets that. In this specific case, this means -37°C instead of the average -53.7°C. The latter is calculated from the average of temperatures between 1991 and 2020 and thus include other heat days at the South Pole. Because the phenomenon is not new, but still unusual. Fortunately, despite the increase, temperatures are still well below last year’s record, when Concordia and Vostok stations, located further up on the Antarctic ice sheet, reported temperatures of -11°C and -20°C, respectively.

Once again, the culprit for the unusually high temperatures is likely to be a shift in the southern jet stream, the undulating high-altitude current that carries warm air masses far into the south while bringing colder air masses farther north. This creates atmospheric rivers that transport heat and moisture. A look at the South Pole Station webcam shows corresponding low clouds and gray skies over Amundsen Scott Station. During the day, the temperature did drop again to -44°C, as reported by the station on the US Antarctic Program website. But this is still far above the temperatures normally prevailing at this time at the South Pole.

Not only the air temperature showed anomalies. Sea ice around Antarctica was also well below normal, confirming that this year the amount of Antarctic sea ice reached a new record low, caused by excessively high water and air temperatures. Image: EU Copernicus

Antarctic sea ice also continues to decline this March, as shown by the map from the EU’s Copernicus satellite mission. Back in February, various agencies reported that a new low for Antarctic sea ice extent had been reached this year. Globally, February was considered the fifth warmest on record in terms of air temperature, according to Copernicus. Overall, the past few months have been marked by massive weather anomalies on both sides of the globe: second warmest winter in Europe, massive droughts in Southern Europe South Australia and South America, but far too wet in Western North America, Northern Australia and South Africa And even if the current warm spell and the resulting “heat wave” at the South Pole are still far below other record values, for many experts it is another shot across the bow that shows that the climate is going off the rails globally.

Dr Michael Wenger, PolarJournal

Featuered photo: Jeff Keller, National Science Foundation

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