Simultaneous Antarctic and Arctic heatwaves in March 2022

Two record-breaking heatwaves occurred simultaneously in the Antarctic and Arctic.
Temperatures reached about 40°C above normal.

Beginning on the 15th of March 2022, two record breaking heatwaves occurred simultaneously in the Antarctic and Arctic. For both poles to display such heating at the same time was both unprecedented and unexpected.

The two heatwaves were not synoptically linked but both were related to similar weather patterns involving warm and moist air being transported surprisingly close to the poles.

In the Southern Hemisphere, a band of westerly winds around Antarctica usually isolates the continent from other weather systems. During the heatwave event, a strong atmospheric river of warm and moist air originating in the mid-latitudes was pumped from near Tasmania and South Australia, breaching the westerly winds. The warm air became trapped over East Antarctica by a blocking high pressure system for a few days. Cloud cover over the Antarctic ice plateau also reduced the amount of heat radiating away from the land. In East Antarctica, temperatures during this heatwave reached ~40°C above normal over large areas of the plateau for a few days.

Daily high temperature (°C) at Dome C, Antarctica. Red dots show the March heatwave temperatures. Source: Climate Reanalyzer, University of Maine.

On March 16th, the Australian coastal station Casey reached 5.6°C, marking a new March maximum temperature that was warm enough to melt ice.

The East Antarctic heatwave drove the overall Antarctic continental average temperature to about 5°C warmer than normal on the 17th of March. The Italian French research station Concordia reached its highest observed temperature for any month of -11.8°C on March 18th, in stark contrast to the usual -50°C March temperatures there.

We cannot yet attribute this heatwave in Antarctica to climate change This does not mean that this heatwave was not linked to climate change. Rather, it means that we will need a longer time record to be able to identify a climate change signal in Antarctic extreme events.