Tropical Weather Directly Linked to Extreme Heat Event in East Antarctica

Journal of Climate, 1 February 2024

A team of five dozen scientists from fourteen countries unraveled the dynamics and impacts of the March 2022 record-shattering heat wave in East Antarctica. This extreme heat event raised temperatures in East Antarctica to an unprecedented +30-40°C above average, breaking not only March records for much of the continent, but setting a new record maximum temperature anomaly for the planet. March typically brings cold weather as the Antarctic winter begins; but in 2022, tropical cyclones in the Indian Ocean distorted the polar jet stream, bringing warm subtropical water vapor swiftly towards Antarctica. Blocking by a high pressure system below Australia then produced the most intense atmospheric river ever observed over East Antarctica; propelling subtropical heat and moisture into the heart of the Antarctic continent. The atmospheric river intrusion led to thick cloud cover, trapping heat in the lower atmosphere and scattering the sun’s rays, ultimately contributing to intense surface warming. At its peak, 3.3 million square kilometers in East Antarctica – an area about the size of India – exceeded previous monthly temperature records. This event triggered the final collapse of the Conger Ice Shelf, which was already critically unstable, and further reduced an already record low sea ice extent in the region. Rain and surface melting were however limited to the coastline, while heavy snowfall occurred further inland. This made 2022 being a rare net positive mass balance year for the Antarctic ice sheet as a whole. However, researchers warn of more catastrophic consequences for ice sheet stability and sea level rise should similar events occur over sensitive West Antarctic ice shelves during the summer. Authors calculated that these temperature extremes occur in Antarctica about once per century, but will increase in frequency if fossil fuel emissions continue on their current path.

Two companion papers: “The Extraordinary March 2022 East Antarctica Heat Wave”
Part 1 – Observations and Meteorological Drivers: https://journals.ametsoc.org/view/journals/clim/37/3/JCLI-D-23-0175.1.xml
Part 2 – Impacts on the Antarctic Ice Sheet: https://journals.ametsoc.org/view/journals/clim/37/3/JCLI-D-23-0176.1.xml