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Temperatures have returned to normal at the poles since the extreme heat recorded last month but scientists remain deeply worried about the future of the Earth’s polar regions.
The planet’s poles made international headlines mid-March amid unprecedented heatwaves. Both the Arctic and Antarctic recorded temperatures between 30-40 degrees Celsius (54-72F) higher than the average.
On Friday March 18, the Concordia research station – located 3,200 metres (10,500 feet) above sea level in the heart of Antarctica – RegisterAn all-time record high of -11.8C (110.8F), 40C higher than seasonal norms.
In parallel, Russia’s Vostok station in East Antarctica broke its previous record for the month of March of -32.7C (-26.9F), reaching -17.7C (0.1F).
Some Arctic regions were warmer than average, reaching 30C.
Last month was made possible by the twin events Fifth-warmest Month of March on record and rang as a warning bell – could climate be breaking down faster than projected?
‘Exceptional’ heat
One month on, scientists remain shocked by the intensity of March’s events, which follow several alarming heatwaves in the summer of 2021.
Last July, temperatures peaked to nearly 50C (122F) in the United States’ Pacific Northwest. Concordia station in Antarctic also set a new winter record for temperatures Reached-26.6C (15.9F), around 40C higher than the normal.
“Strongly fluctuating temperatures are something we traditionally witness in Antarctica, and are not exceptional. The exception is the This event was of immense magnitude,” astrophysics professor Tristan Guillot from the French national research centre CNRS told Al Jazeera.
Guillot and his team, who analyse data from the Concordia station, were at the front row to witness the unprecedented polar heat.
Antarctica is now entering autumn, and temperatures should have been dropping sharply since December 21st. Still, “this peak in inland temperature had little impact in practice”, Christophe Genthon, a research meteorologist at CNRS, highlighting the “temperature remained well below anything that would have allowed the ice to melt”.
Concordia and Vostok stations are located deep within the Antarctic continent and sit on more than three kilometres (1.2 miles) of ice – which have been piling up there across thousands of years, in a part of the continent that has been surprisingly protected from warming temperatures.
“Climate has remained remarkably stable in East Antarctica over the past years compared to West Antarctica, which has warmed up markedly,” Genthon told Al Jazeera.
There are many reasons this could be. Some scientists point to the natural variability of weather in East Antarctica, which could have “buffered” global warming trends, or to the recovery of the ozone layer thanks to the adoption of the Montreal protocol in 1989, which bans the use of certain products responsible for ozone depletion. The ozone layer plays an important role in blocking out the sun’s ultraviolet radiation, which warms up the atmosphere.
Peter Neff, a glaciologist and assistant research professor at the University of Minnesota, said, “One of the reasons that Antarctica is not warming as strongly as many places on the planet is that it’s so big and it has such steep margins that it keeps a lot of that heat out.”
Analysts expect to see warmer airflows into Antarctica due to the warming of the Southern Ocean off Australia’s coast.
Atmospheric rivers
The temperature spike in Antarctica was caused by an “atmospheric river”, Neff told Al Jazeera, “a channelised stream of moisture that sort of gets pinched between a high and a low-pressure system”.
Atmospheric rivers collect water vapour from moist and warm areas, transport it for thousands of kilometers, and then drop it as rain or snow when they cool down in colder places.
“It actually did us a favour this time in that the snowfall carried by the atmospheric river over East Antarctica added about 69 gigatons of ice volume back onto the ice sheet,” Neff said. “This means some of that ice we’re losing every year in the ocean can jump back on the ice sheet in a big snowfall event.”
This is a substantial, but insufficient, portion of the 150 gigatons of Antarctica’s average annual ice loss.
The March events were not without consequences. In Dumont d’Urville, located off the coast of East Antarctica, unusual heat and rain were recorded.
“Rain is not exceptional on the Antarctic coast but it is rare, particularly in March, and can have important impacts on wildlife and on the stability of the Antarctic ice cap with potentially global consequences,” Genthon said.
A significant portion of the ice shelf’s destruction was likely due to rising heat. collapsesSince the early 2000s, Antarctica. Conger ice shelves, consisting of interlinked glaciers, covered 1,200 km (463.3 miles) of East Antarctica on March 15. This occurred three days before Concordia’s record. Although it had been shrinking since the mid-2000s, the heat wave was likely the “final straw” for Conger.
This is significant as ice shelves play a crucial role in preventing the enormous volumes of ice piled on Antarctica, from slipping into seawater. A further collapse could allow huge glaciers to plunge into the sea, which would have a greater impact on global sea level.
Long-term trends
Antarctica has the shortest observational record on Earth – weather data has only been collected since the late 1950s across a few locations- making it hard to assess the historic significance of the event.
“The link between the exceptional temperatures that were recently recorded and climate change is hard to establish,” Genthon said.
Scientists are concerned about the intensity of polar heatwaves.
“These events seem to be getting bigger,” said Guillot. “We don’t have complete studies yet to prove the link to climate change, but there are huge suspicions among the scientific community – there is not much doubt the two are linked.”
Neff stated that the events were in line with predictions made by climate scientists. “We know that we should expect more heat and more warming through the rest of the century and beyond.”
The Latest report by the International Panel on Climate Change (IPCC), an international panel of scientists, warned the Earth’s polar regions are already going through “irreversible” changes.
In Antarctica, the IPCC projects a significant increase in the number of days above freezing in certain parts of the continent – 50 additional days per year by 2100.
In the Arctic, climate change impacts are already occurring “much faster” than in any other region.
Sea ice surface is now shrinking by 13 percent every 10 years on average, which could drive dozens of endemic species – including seals and polar bears – to extinction in certain areas and drive sea levels up significantly.
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