Antarctica's changing weather and climate

Climate change impacts have emerged in recent years in Antarctica. Examples include:

• the catastrophic collapse of ice shelves in the Antarctic Peninsula and West Antarctica
• the record decline in Antarctic sea ice
• breeding failure of Emperor penguins.

More recently, we’ve witnessed the surprising appearance of extreme weather events in Antarctica. In March 2022, large parts of East Antarctica experienced a record-breaking heatwave with temperatures soaring 39°C above normal. While this heatwave lasted only a few days, the event was connected to:

• the collapse of the Conger Ice Shelf (the first ice shelf in East Antarctica to fail)
• changes in sea-ice condition
• changes in ocean circulation.

A growing network of ocean monitoring stations detected no less than 19 ocean heatwaves. Research teams observed waterfalls gushing off ice shelves, and documented the occurrence of rainbows, which evidence liquid water droplets in the air.

As global temperatures rise, regional and local patterns in Antarctica must be understood to effectively monitor change. Much of our work has focused on downscaling from regional patterns to local processes to help better understand the impacts of changing climate.

Using the AntAir ICE dataset, ASP researchers identified air temperature trends and extreme events across Antarctica between 2003–2021. Analysis confirmed a spatial variation across the continent, with a significant cooling over the Antarctic Peninsula and significant warming in the Ross Sea region, especially near coastal Victoria Land and the Transantarctic Mountains.

Different processes drove warming events across the continent. West Antarctica experienced localised extreme temperatures due to the transport of warm, moist air from further north. East Antarctica showed widespread warming driven by a large inland high-pressure system. Northward air flow (katabatic winds) from the interior toward the coastline manifested as additional warmth due to air being heated as it compressed down the elevation gradient.

Another key discovery was the impact of Foehn winds on surface temperature in the McMurdo Dry Valleys, especially in winter. When regional winds are light, cold air can settle in the valleys, causing temperatures to drop below -50°C. But when Foehn winds occur, they push warm air down into the valleys, raising temperatures by as much as 40°C in just a few hours. These warm wind events are becoming more frequent in winter, which explains the slow rise in annual temperatures in the Dry Valleys.