Antarctica is warmer than it should be
Eyal Bartov / Alamy
Since the beginning of September, temperatures in the atmosphere above the Antarctic have climbed more than 35 ° C (63 ° F), while the wind speeds have been reduced and the exhaustion of ozone suddenly blocked.
This type of upheaval should only occur once every 20 years, explains Martin Jucker at the University of New South Wales in Sydney, Australia. Instead, these events seem to become more frequent, with short -term short -term disruptions last year, and more serious events in 2019 and 2002.
Jucker says that four of these events in less than a quarter of a century indicate that alarming changes are underway in the global climate system.
Atmospheric temperatures of Antarctica should normally be -55 ° C (-67 ° F), but since September 5, they have increased inexorably to -20 ° C (-4 ° F). Although it is still freezing, it means that the wind speed in the stratosphere – the polar vortex – has fallen half kilometers relatively calm per hour.
Getting does not yet constitute the formal definition of a sudden event of stratospheric warming, explains Jucker. To reach this threshold, the winds should stop completely during a warming of sustainable days, not a few weeks. However, he said, the implications for the southern hemisphere in the coming months could be significant.
Meteorologists in Australia, which initially predicted a more humid spring than normal, now warn powerful potential westerlies on the Australian continent, leading to warmer and drier conditions.
The strange time is not yet finished. Some scenarios can take place in the coming weeks, explains Jucker. The first is that the polar vortex is recovered and atmospheric temperatures come back to the average trend line.
Alternatively, the anomaly could continue, certain suggestions according to which the elevation of the atmospheric temperature could increase 20 ° C (36 ° F). Consequently, the northern latitudes of the southern hemisphere could be in a wild time.
Although the cause of the anomaly has not yet been scientifically established, Jucker says that it is almost certain that the increase in sea surface temperatures due to climate change, between 1 ° C (1.8 ° F) and 2 ° C (3.6 ° F) in the Pacific, leads to the current slowdown in the polar whirlwind.
“We also had these three massive typhoons in the Pacific, which are also due to temperatures on the surface of the sea,” explains Jucker. “We have generally had a very strange time in the past two years and that everything coincides with this very big leap to the ocean temperature.”
Edward Doddridge at the University of Tasmania, Hobart, Australia, says that the list of extreme changes at the bottom of the world is growing. In recent years, there has been a loss of sea ice, heat waves, generalized breeding failures in the Emperor penguin colonies and a spectacular slowdown in the circulation of reversal of the Antarctic.
“Antarctica surprises us,” he says. “Although each of these changes is worrying in themselves, my greatest concern is that we are starting to see changes that not only strengthen, but also in cascade through different parts of the Antarctic Environment.
“Loss of sea ice in summer improves the rupture of ice shelves and causes warming of the ocean. These warmer ocean waters melt the ice shelves remaining faster, and this fresh water slows down the antarctic reversal circulation, ”explains Doddrige.
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