The Largest Ever Recorded Heatwave—Characteristics and Attribution of the Antarctic Heatwave of March 2022

An extreme heatwave took place in East Antarctica in March 2022, which registered the most anomalous temperatures above local climatology ever recorded. The heatwave resulted from a highly unusual weather pattern which produced strong northerly winds and imported warm and moist air from Australia. Weather forecast models skillfully predicted the heatwave up to 8 days in advance. While the heatwave took place soon after the record sea ice minimum of February, Southern Ocean sea surface temperature anomalies had a minimal impact on the magnitude of the heatwave. We have found that a widely used climate model cannot simulate heatwaves of this magnitude, but when the model’s winds in the free atmosphere are nudged toward observations, the model can simulate a heatwave closer to observations, suggesting model improvements in atmospheric circulation variability would lead to better heatwave simulation. To address the impact of climate change, we have re-run the model simulations, nudging to the same winds but under past and future anthropogenic forcing. We find that the heatwave was made 2°C warmer by climate change, and future end of century heatwaves to be 5–6°C warmer, suggesting the possibility of near-melting temperatures over the East Antarctic ice cap during extreme heatwaves.