Arctic and Antarctic See Extreme Heat and Historically Low Sea Ice

Abnormally hot air has hit both of the world's poles at once, while the extent of Arctic sea ice appears to have been historically low this winter. From a report: Temperature records were broken in Antarctica as warm air swept unusually far into the heart of the continent. Concordia station, which is high above sea level and has an annual average temperature of -50C, reached an all-time high of -12.2C on 18 March, beating the -13.7C record set in December 2016. Another research station, Vostok, also saw record high temperatures. "The Antarctic [heat] is really extreme. I haven't seen anything like that. Colleagues haven't seen anything this extreme," says Walt Meier at the US National Snow and Ice Data Center (NSIDC) in Boulder, Colorado. A band of westerly winds around Antarctica usually isolates the continent from other weather systems. But in the past week, an "atmospheric river" of hot air, originating in the mid-latitudes, travelled down from Tasmania and South Australia, breaching those winds to travel far across the ice, says John Turner at the British Antarctic Survey. Although such events aren't unprecedented, the temperatures this time are very high. Turner says while it is undoubtedly an "extreme event," he thinks the Antarctic heat looks like natural variability rather than climate change. Past research by Turner has found no discernible trend in extreme temperatures in Antarctica, where the hole in the ozone layer appears to have cancelled out the impact of global warming so far. The recent highs won't have any consequences such as impacts on landing strips for scientists stationed on the continent either, says Ted Scambos at the University of Colorado, Boulder, because most have already departed ahead of the Antarctic winter and those remaining are hunkered down with supplies. The record temperatures come shortly after Antarctic sea ice declined to a record low minimum extent, at 1.92 million square kilometres on 25 February. "It was quite a lot lower than anything else in the 40-plus year record," says Scambos.

Read more of this story at Slashdot.