Climate warming amplified the 2020 record-breaking heatwave in the Antarctic Peninsula

Abstract

February 2020 was anomalously warm in the Antarctic Peninsula region and registered one of the most intense heatwaves ever recorded in Western Antarctica. The event featured unprecedented regional mean temperature anomalies (+4.5 °C) over the Antarctic Peninsula between 6 and 11 February 2020 and the highest local temperature of the continental Antarctic region. Taking flow analogs of the event from past (1950–1984) and recent (1985–2019) periods of the ERA5 reanalysis, here we quantify the role of recent climate change in the magnitude of this 6-day regional heatwave. Results show that 2020-like heatwaves over the Antarctic Peninsula are now at least ~0.4 °C warmer than in the past period, which represents a ~25% increase in magnitude. Given the observed atmospheric circulation conditions, the probability of experiencing 6-day regional mean anomalies above ~2 °C has increased ten times since 1950–1984. The aggravated severity of the event can be largely ascribed to long-term summer warming of the Antarctic Peninsula rather than recent atmospheric circulation trends.

High Resilience and Fast Acclimation Processes Allow the Antarctic Moss Bryum argenteum to Increase Its Carbon Gain in Warmer Growing Conditions

“…In line with this prediction, in March 2022, large parts of East Antarctica experienced an extreme heatwave never before recorded in the more than 60 years of instrumented records [ 3 ]. In maritime Antarctica where general warming and a high frequency of heatwaves have already been experienced [ 86 , 88 ], moss growth rates are much higher than that in continental Antarctica, with rates of moss organic matter accumulation up to three times higher [ 89 ]. With the versatility in carbon gain seen under our pulse warming treatment, mosses in continental Antarctica are likely to increase growth rates and potentially expand in coverage or density under predicted short- or long-term warming.…”

Climate change and extreme events are changing the biology of Polar Regions

“…Extreme events are happening more frequently in polar regions (Bokhorst et al, 2022; González‐Herrero et al, 2022; Robinson et al, 2020), These often occur outside of the growing season (Chown et al, 2022; Constable et al, 2022; Treharne et al, 2019), making them more challenging to study. As temperatures rise, ice‐free areas will expand in Antarctica as they have in the Arctic, but there is still considerable uncertainty as to how Antarctic species will be affected as their habitats transform (discussed in Lee et al, 2022).…”

Antarctica's vegetation in a changing climate

“…This, however, is set to change and there is high confidence in future warming across all of the continent (Meredith et al, 2019), especially in coastal areas due to stronger relative Southern Ocean warming and relatively stronger effects of ozone recovery (Bracegirdle et al, 2020). Heatwaves are an additional concern and high-temperature records have been recently documented from several locations all across Antarctica (Gonz alez- Herrero et al, 2022;Robinson et al, 2020;Wille et al, 2019).…”

“…However, regional effects are complicating continent‐wide predictions. Over the last half of the 20th century, the western Antarctic Peninsula, and maritime Antarctica in general, has been one of the most rapidly warming regions on the planet, leading to substantial reductions in sea ice and mass loss of outlet glaciers (Chen et al, 2022; González‐Herrero et al, 2022; Hobbs et al, 2016). In contrast, the warming trends in continental Antarctica have been localized and inconsistent (Stenni et al, 2017; Turner et al, 2020).…”