Summer 2024 is expected to be the hottest on record for hundreds of cities in the U.S. and around the world, with even Antarctica experiencing extreme heat during the peak of its winter. A study published in Earth’s Future journal revealed how heat waves, especially those in Antarctica’s cold seasons, could affect the animals living there. The research highlights the potential implications of climate change-induced extreme weather events on the fragile ecosystems of the continent.
In March 2022, Antarctica experienced the most intense heat wave ever recorded on Earth, with temperatures soaring more than 70°F above average, causing glaciers and snow to melt even in the McMurdo Dry Valleys, one of the coldest and driest regions on the planet. The Long-Term Ecological Research (LTER) project in Antarctica found that the rapid melt followed by refreezing disrupted the life cycles of many organisms in the region, resulting in the deaths of a large number of invertebrates.
Michael Gooseff, the senior author of the study and a professor at CU Boulder, emphasized the importance of paying attention to signals from microscopic organisms in polar deserts, as they could indicate broader changes that could impact larger organisms and landscapes, even far away from Antarctica. Gooseff has been leading the LTER project in the McMurdo Dry Valleys for the past decade, studying how organisms survive in extreme environmental conditions in Antarctica.
The unexpected heat wave in Antarctica in 2022 was driven by an intense storm known as an atmospheric river, which transported moist air to the polar region, causing temperatures in the McMurdo Dry Valleys to rise above freezing and exceed average temperatures by 45°F. Satellite imagery and stream discharge measurements showed that the heat wave wetted the soil in the valleys, two months after the peak summer thaw, disrupting the transition period when organisms prepare for the dark, cold winter.
The team observed a 50% decrease in the population of Scottnema, a roundworm adapted to cold and dry climates, in areas that became wet during the heat wave. The heat wave created a false start to summer, disrupting the biology of the organisms in the region. Rapid swings in weather extremes can disproportionately impact sensitive species like Scottnema while having less impact on creatures like tardigrades, which have a higher tolerance for moisture and can proliferate as the environment becomes wetter.
As climate change continues to exacerbate extreme weather events in Antarctica, larger species such as Adélie penguins are also being impacted. In previous instances, unusual rainfall events and extreme temperatures have resulted in significant consequences on the ecosystem. Gooseff and his team plan to continue documenting the impacts of extreme weather events on the Antarctic ecosystem, emphasizing that what happens in Antarctica can have far-reaching effects on ecosystems and communities thousands of miles away.