At a research station in East Antarctica, scientists recorded something unprecedented: a heatwave. The scientists made the measurements at Casey Station, one of only three permanent stations on the ice-covered continent. They observed the record-breaking hot weather this year from January 23-26 (that was summertime in Antarctica, which is in the Southern Hemisphere). The findings were reported recently in Global Change Biology.
To be considered a heatwave, both the minimum and maximum temperature must be abnormally high for at least three consecutive days. Late January in East Antarctica checks this box. The Casey Station observed its highest maximum temperature ever recorded on January 24, clocking in at around 49 °F (9.4 °C). This is more than 10 °F higher (5 °C higher) than average maximum temperatures seen at the station over the past 30 years. They also recorded the highest minimum temperature ever the morning after January 24.
While the heatwave in East Antarctica was the focus of the recent report, another record in Antarctica was broken this year. Soon after the heatwave, scientists at another research station in Antarctica measured the highest temperature ever recorded across the entirety of the continent. On February 6, they observed temperatures a little over 65 °F (18.3 °C). These broken temperature records exacerbate concerns about the Antarctic ice sheets’ uncertain future. Polar ice loss is now the dominant cause of sea level rise, and heatwaves and high temperatures will worsen that problem.
In the past, East Antarctica has been spared from the same kind of rapid warming the rest of the world has endured. This is largely because of the Antarctic ozone hole, which is slowly recovering but still present every year over the Eastern part of the continent. The ozone hole and climate change are two distinct environmental problems. Yet, they do have a slight connection here. Even very high up in the atmosphere, the ozone traps some of the heat that would otherwise escape the planet. The ozone layer’s greenhouse effect is weak, so the ozone hole counteracts some of the warming caused by the CO2 we emit, allowing some heat to escape. This year, the scientists pointed out that the ozone hole healed earlier than usual. The unexpected uptick in ozone, coupled with the ever higher man-made greenhouse gas levels, is the most likely cause of Casey Station’s extraordinary heat this January. As the planet continues to rapidly warm, scientists emphasize that we should expect more broken records in Antarctica soon.
Managing Correspondent: Jordan Wilkerson
Scientific Article: The 2019/2020 summer of Antarctic heatwaves. Global Change Biology.