Temperatures at the poles have returned to normal since extreme heat was recorded last month, but scientists remain deeply concerned about the future of Earth’s polar regions.

Earth’s poles made international headlines in mid-March amid an unprecedented heatwave. Temperatures in the Arctic and Antarctic are 30 to 40 degrees Celsius (54-72 degrees Fahrenheit) above average.

The Concordia Research Station at 3,200 m (10,500 ft) in central Antarctica recorded an all-time high of -11.8C (110.8F) on Friday, March 18, 40C above the seasonal norm.

Meanwhile, Russia’s Vostok in East Antarctica broke its previous record of -32.7C (-26.9F) in March, reaching -17.7C (0.1F).

Meanwhile, some parts of the Arctic are warming to 30 degrees Celsius above average.

The two events helped last month fifth hot moon March on the record, and a wake-up call – will the climate collapse sooner than expected?

“Extraordinary” heat

A month on, and after several shocking heatwaves in the summer of 2021, scientists are still stunned by the intensity of the March event.

Temperatures in the US Pacific Northwest peaked at nearly 50 degrees Celsius (122 degrees Fahrenheit) last July. In Antarctica, Concordia station also broke winter records, with temperatures reaching -26.6C (15.9F), about 40C above normal.

“The wildly fluctuating temperature is a phenomenon we have traditionally seen in Antarctica, and it is no exception. The scale of this event is extraordinary,” Tristan Guillot, professor of astrophysics at the French National Research Centre CNRS, told Al Jazeera.

Guillot and his team analyzed data provided by the Concordia station, where they observed unprecedented polar heat in the front row.

Antarctic heatwave has lasted a full week since the end of March, with temperatures back within normal ranges [ASTEP/IPEV/PNRA/C Genthon/T Guillot]

Antarctica is entering autumn and temperatures should drop sharply since December 21st. Still, “this spike in inland temperatures has little impact in practice,” stressed Christophe Genthon, a research meteorologist at CNRS. “The temperature is still well below anything that might be expected. Let the ice melt.”

The Concordia and Vostok stations are deep in the Antarctic continent, sitting on more than 3 kilometers (1.2 miles) of ice that has accumulated for thousands of years and is located in a part of the Antarctic continent that is unexpectedly protected from rising temperatures high impact.

“The climate in East Antarctica has been very stable over the past few years compared to West Antarctica, which is noticeably warmer,” Gentong told Al Jazeera.

There are many possible reasons for this. Some scientists have pointed out that natural variations in East Antarctica’s weather may have “buffered” global warming trends, or restored the ozone layer to deplete the ozone layer due to the 1989 Montreal Protocol, which banned the use of certain responsible products. The ozone layer plays an important role in blocking the sun’s ultraviolet radiation, which warms the atmosphere.

Peter Neff, a glaciologist and assistant research professor at the University of Minnesota, said: “One of the reasons Antarctica isn’t warming as strongly as many places on Earth is that it’s so big and the edges are so steep that it keeps a lot of heat out all the time. .”

But as temperatures rise in the Southern Ocean off the coast of Australia, analysts expect more warm air to move into Antarctica and possibly more heatwaves.

atmospheric river

Neff told Al Jazeera that the temperature spike in Antarctica was caused by an “atmospheric river”, “a channelized flow of water sandwiched between a system of high and low pressure”.

Atmospheric rivers collect water vapor in humid and warm regions, carry it thousands of kilometers, and fall as rain and snow as it cools in cooler regions.

“This time actually did us a favor, because the snowfall brought by atmospheric rivers over East Antarctica added about 69 gigatons of ice back to the ice sheet,” Neff said. “This means that some of the ice we lose in the ocean each year can come back onto the ice sheet during heavy snow events.”

This is a significant, albeit deficient, portion of the 150 trillion tons of ice that Antarctica loses on average each year.

Still, the events of March were not entirely without effect. Unusually high temperatures and rainfall were recorded in Dumondville, off the coast of East Antarctica.

“On the Antarctic coast, rainfall is not uncommon, but it is rare, especially in March, and can have important implications for wildlife and the stability of the Antarctic ice sheet, with possible global consequences,” Genthon said.

One of the worst ice shelf collapses in Antarctica since the early 2000s may also be responsible for rising temperatures. The Conger Ice Shelf, which consists of interconnected ice sheets covering 1,200 square kilometers (463.3 square miles) of sea on the eastern edge of Antarctica, broke up on March 15, three days before the peak recorded by Concordia. Although it has been shrinking since the mid-2000s, the heatwave may have been Conger’s “last straw”.

That’s important because ice shelves play a key role in keeping the huge amount of ice that’s accumulated in Antarctica from slipping into the sea. Further collapse could sink huge glaciers into water, which would have an even bigger impact on global sea levels.

long term trend

Antarctica has the shortest observational record on Earth—weather data has been collected at only a handful of locations since the late 1950s—making it difficult to assess the historical significance of the event.

“The link between recently recorded abnormal temperatures and climate change is difficult to establish,” Genthon said.

But scientists are generally concerned about an increase in the intensity of polar heatwaves.

“These events seem to be getting bigger,” Guillot said. “We don’t have the full study to prove the link to climate change, but there’s huge skepticism in the scientific community — there’s no doubt there’s a link between the two.”

Neff added that the events were consistent with predictions by climate scientists. “We know we should expect more heat and more warming for the rest of the century and beyond.”

The planet’s polar regions are already undergoing “irreversible” changes, warns the latest report from the International Panel on Climate Change (IPCC), an international panel of scientists.

In Antarctica, the IPCC expects a significant increase in the number of days above freezing in some parts of the continent—by 50 days a year by 2100.

In the Arctic, the effects of climate change are already happening “faster” than any other region.

Sea ice surfaces are now shrinking by an average of 13 percent every 10 years, which could lead to the extinction of dozens of endemic species, including seals and polar bears, in some areas, as well as a significant rise in sea levels.