There are days, the temperature in parts of East Antarctica exceeded average measurements by 30 degrees, and in the case of the Franco-Italian Concordia base, the mark exceeded the usual average of 40 degrees. Of the -55 degrees expected for the time, thermometers were around -12 degrees Celsius.
The origin of this heat wave was due to a large historic atmospheric river, a column of concentrated moisture that carried warm air from warmer waters. This caused an incredible accumulation of snow inside the ice cap, something quite rare in this polar region.
In what could be considered a different phenomenon, The Conger Ice Shelf, a similar piece of ice in Los Angeles, collapsed into the sea around the same time on March 15, satellite images showed..
Scientists are studying for make sense of what happened. The recent and surprising temperature and humidity records force changing perspective on climate in Antarctica and raise questions about the impact this might have in the future.
Some researchers say it’s too early to tell what role does climate change play here, if any. In the meantime, these extreme oscillations are the subject of new studies.
This satellite image provided by NASA in February 2022 shows the collapse of the Conger Ice Shelf in East Antarctica, an area long thought to be stable (NASA via AP)
“We didn’t think such a magnitude of heat was possible in Antarctica, especially during what should be the coldest season“, he said of the heat wave Jonathan Wille, postdoctoral researcher at the University of Grenoble Alpes in Franceadding: “We have never seen the atmosphere behave like this over Antarctica.”
The heat wave and dramatic snowfall inland highlight the importance of a better understanding of the complicated dynamics of atmospheric rivers, which now reinforce the ice sheet but could be of concern in the future. A better understanding of these patterns could be essential for understand the future of the polar region.
Wille added that it is possible that this type of weather is a rare and unusual phenomenon, something that could happen. once every 100 years, regardless of climate change. Researchers may not have measured Antarctica’s climate trends long enough to witness such an anomaly before, he said. Heavy snowfall during a heat wave might seem like a counter-intuitive phenomenon, but this is Antarctica after all, where inland winter temperatures regularly drop below minus 60 degrees.
The recent atmospheric river event unfolded over several days. March 17 was the fourth wettest day since 1980 in Antarctica.according to the modeling and analysis of Xavier Fettweis, professor of climatology at the University of Liège in Belgium. “An extreme event of this magnitude has never been observed. in Dome C,” said Peter Neff, a glaciologist and climatologist at the University of Minnesota, referring to the Concordia region.
Coastal temperatures exceeded freezing levels and rain hit the coast. Heavy snowfall inside East Antarctica added about 69 gigatonnes of water mass to the ice sheet., according to the Fettweis model. It is the equivalent of almost 28 million Olympic pools of added water mass that fell in frozen form. This represents more than a third of Antarctica’s annual ice loss..
“Events like this help mitigate some of the sea level rise caused by climate change by storing water as polar ice.“, explained to the NBC network, the researcher from the University of Grenoble. For this reason, snowfall also provides important protection. Some Antarctic pack ice, the floating ice that clings to the Antarctic coastline, is losing mass and is at risk of collapsing into the sea. Currently, much of this risk comes from melting ice from below, due to the warming water temperatures.
“Snowfall is a good thing, because it adds to this buffer layer on the surface of this ice cap. The damper can absorb more cast iron in the future“, noted Michelle Maclennan, PhD student at the University of Coloradowho studied the effects of atmospheric rivers in West Antarctica and on the Thwaites Glacier.
“It’s hard to judge what the impacts might be, but this event really challenges us to change our understanding of what the range of extremes has been“said the researcher.
So-called “rivers in the sky” or atmospheric rivers are not uncommon in Antarctica. Previous research by Wille suggests that they are responsible for around 10-20% of the total snowfall in East Antarctica. West Antarctica can see anywhere from a handful to more than 10 such events a year, Maclennan said.
In Antarctica, it can be difficult to know what is normal or expected. Temperatures can fluctuate wildly, the continent has relatively few weather stations, and satellite observations are only about 40 years old. “The classic problem in Antarctica: everything is against you to be able to put anything in context”, ironically one of the researchers.
These patterns come from oceans and warmer latitudes. “They’re like wet fire stationssaid the University of Minnesota glaciologist. This fire hose in mid-March was the strangest ever seen in Antarctica.
The anomaly posed by these extreme weather phenomena opens new questions. How these patterns play out in the future could have significant consequences for ice shelves and sea level rise around the world.
The imprint of climate change has not been evident in this region as is the case in other parts of the world. Was the heat wave a new sign of its impacts? Researchers don’t know yet.