Temperatures in the Antarctic climbed above 15C this month, shattering the previous winter heat record for the usually frozen region and raising concerns about the speed of climate breakdown.
The new winter peak temperature was logged by the Argentinian Esperanza base on the Trinity peninsula on 6 June amid a protracted heatwave, when the maximum daily temperature exceeded zero degrees for three consecutive weeks.
Scientists said the high of 15.4C broke the previous record set at the same station in 1998 by 2C. “This is absolutely crazy,” said Raúl Cordero, an Ecuadorian climate professor at the University of Groningen. “It is also about 20C above normal for this time of the year. That is a huge anomaly.”
Unusually strong warm winds from the north blew across much of the Antarctic peninsula. One Chilean weather station, Boonen Rivera, registered temperatures of close to 13C, Cordero said.
On King George Island, 100 miles (160km) from Esperanza, researchers said the landscape had changed from mostly white to brown, grey and green after temperatures hit 4.6C on 6 June.
“Last weekend was very strange. The temperatures here went very high so everything outside melted,” said Luis Muñoz, a Chilean glaciologist. “Usually there is 20cm of snow and a lot of ice on the ground at this time.”
Muñoz said he and a colleague, Natalia Mestre, climbed to the 500-metre peak of the nearby Collins glacier last Wednesday and were surprised to find rain melting the ice. “There was a direct impact on the glacier, which should be receiving snow now. It should not be suffering ablation at this time of the year. This is obviously not good for the glacier.”
The Antarctic region is coming under increasing human pressure, directly in the form of resource exploration and tourism and indirectly through the burning of fossil fuels, which is heating the planet.
Scientists warn that some of the region’s biggest glaciers, such as Thwaites and Pine Island, are approaching or may even have passed a tipping point that could push up global sea levels by four metres. Antarctic ice melt has also been found to slow global ocean circulation.
Cordero said a single winter of heatwaves, no matter how amazing, would not by itself make a huge difference to sea levels, but it signified more alarming long-term trends. “This heatwave happened because of extremely strong westerlies,” he said. “This has been happening with increasing frequency since the 1980s, and that is known to be related to climate change.”
