Attribution of Austral Summer Extreme Temperature Events in Antarctica Using a Circulation Analogue Method

The global climate system is undergoing rapid changes unprecedented in human history, with increasingly extreme weather events observed across the world. Antarctica is particularly exposed to these changes, with some of the highest warming rates on the planet recorded over West Antarctica in recent decades and emerging warming trends now evident in East Antarctica. Despite this, relatively few studies have focused on the attribution of extreme temperature events in Antarctica, where near-surface temperatures are strongly conditioned by large-scale atmospheric circulation over the continent and the Southern Ocean. 

Here, we apply a circulation-analogue technique for extreme-event attribution to assess how dynamically similar warm extremes have changed over time. We focus on three recent austral-summer warm extremes: the February 2020 heatwave over the Antarctic Peninsula, the March 2022 warm anomaly across East Antarctica, and the March 2015 warm spell on the Peninsula. These short-duration events produced exceptional near-surface temperature anomalies. 

Circulation analogues associated with these events are analysed across two climatic periods: a “past’’ baseline (1948–1986) and a “present’’ period (1987–2025), using two independently developed atmospheric reanalysis products, ERA5 and JRA-3Q. Changes in the occurrence frequency of analogue weather types and in their associated near-surface temperature anomalies provide insight into the influence of anthropogenic climate change on these extremes. The dual-dataset approach offers a more robust basis for attribution, particularly for the pre-satellite era when reanalysis uncertainties and dataset discrepancies are considerable.