First heatwave in Antarctica


Even the coldest continent in the world is not immune to rising global temperatures. While drought and wildfires have plagued areas such as Australia, an international team of scientists has just recorded the first heatwave in Antarctica during the 2019-20 summer period.

A heatwave in the coldest place on earth

A heatwave is determined when there are three consecutive days with extreme maximum and minimum temperatures and according to the records of the Casey Station in East, Antarctica experienced a heatwave earlier this year, in January. Record temperatures were also noted at the bases of the Antarctic Peninsula.

Between January 23 and 26, minimum temperatures were above zero degrees Celsius while maximum temperatures reached a high of 7.5 degrees. On January 24, Casey's team recorded a record temperature of 9.2 degrees Celsius, 6.9 degrees higher than the average maximum at the Antarctic station.

At the same time, record temperatures were also noted on the other side of the continent, on the Arctic Peninsula. During the month of February, the highest temperature ever recorded was 18.3 degrees, followed by an alarming reading of 20.7 ºC just one week later, at the Argentine research station, Base Esperanza. These patterns were influenced in part by the early rupture of the ozone hole in late 2019, due to rapid warming in the stratosphere.

The paper, published in the journal Global Change Biology by scientists from the University of Wollongong (UOW), the Australian Antarctic Division (AAD), the University of Tasmania and the University of Santiago in Chile, therefore confirms the first heatwave on the icy continent and its impact on Antarctic plants, animals and ecosystems.

What harm can it do to the fauna and flora? Long-term consequences

"Based on our experience of previous abnormally hot summers in Antarctica, we can expect a multitude of biological impacts to be reported in the coming years," the authors explain.

Animal and plant life on an isolated continent could be dramatically affected by climate change. High temperatures will precipitate increased melting, which could lead to dramatic changes in invertebrate and microbe communities.

Such high temperatures can cause heat stress in some of their organisms, and while the precise impact will not be entirely clear for years, researchers already have an idea of what this will mean for the ecosystem.

"Most life exists in small ice-free oases in Antarctica, and relies heavily on melting snow and ice for its water supply," says Antarctic ecologist Dana Bergstrom. "Meltwater floods can provide additional water to these desert ecosystems, leading to increased growth and reproduction of mosses, lichens, microbes and invertebrates. However, excessive flooding can wipe out plants and alter the composition of invertebrate and microbial mat communities. If the ice completely melts early in the season, ecosystems will suffer drought for the rest of the season.

The warming trend continues across the globe: January 2020 was ranked the hottest January in the 141-year climate record. 

Reference: Sharon A. Robinson et al. The 2019/2020 summer of Antarctic heatwaves, Global Change Biology (2020). DOI: 10.1111/GCB.15083



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