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Animals are increasingly threatened by heatwaves worldwide

Due to climate change, extreme weather events such as heatwaves are becoming more frequent, longer, and more intense. For instance, in 2022, heatwaves reached unprecedented levels, killing over 15,000 people worldwide. Besides affecting humans, these extreme thermal events also have disastrous effects on wildlife. Since many animals are adapted to live in certain temperature ranges, prolonged exposure to extreme heat can cause massive die-offs, and thus disrupt a variety of ecosystems.

By using species data for most terrestrial vertebrates (33,548 species of amphibians, birds, mammals, and reptiles) regarding recent exposures to heatwaves, along current distribution ranges and projections of climate change under different greenhouse gas emissions scenarios, a team of researchers led by Ben-Gurion University of the Negev in Israel has now predicted the effects of future extreme temperatures on land-based animals by the end of this century. 

The analysis revealed that while thousands of species are likely to be regularly exposed to future heatwaves, the number of exposed species will become significantly larger under high-emissions scenarios.

“By 2099, under the highest greenhouse gas emission scenario, we estimate two in five species of all land-vertebrates will experience extreme thermal events with temperatures beyond their historical levels in at least half their distribution range,” said study lead author Gopal Murali, a postdoctoral fellow at the University of Arizona, who conducted this research at Ben-Gurion.

“We also found that by 2099 in this scenario, 3,773 species, or 11 percent of total land vertebrates are likely to face extreme thermal events during most of the year. However, a low-future emissions scenario greatly reduces animals’ exposure to heat extremes. In this scenario, just 6.1 percent of all land vertebrates will have most of their ranges exposed to extreme heat events, and none during most of the year.”

The experts determined that amphibians and reptiles are much more at risk than other land-vertebrates, most likely due to their overall smaller distribution ranges, which may prevent them to relocate in areas less exposed to extreme temperatures. Interestingly, extreme temperatures will probably also substantially affect species in the drier regions of the globe, such as deserts, shrublands, and grasslands across North America, Africa, and Australia.

The findings have major implications for biodiversity conservation. “We need to start considering the impacts of extreme heat events when making conservation and land management decisions. The biodiversity crisis is upon us and many species may go extinct due to various human actions. If unchecked, climate change may soon become a final nail in their coffin. The time to act is now,” concluded senior author Uri Roll, an expert in Conservation Biology at Ben-Gurion.

The study is published in the journal Nature.

By Andrei Ionescu, Staff Writer

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