Heat waves to increase, affect wildlife – BGU

Last year, heat waves reached unprecedented levels, breaking records across many countries and leaving as many as 15,000 people dead. These extreme thermal events also have dire effects on wildlife.

Most animals are adapted to live in a specific temperature range, and prolonged exposure to extreme heat has already caused mass deaths in many species, but until now, no one has examined how future extreme thermal events that are projected to increase and intensify, will affect animals around the world.

In a new paper in the prestigious journal Nature entitled “Future temperature extremes threaten land vertebrates,” a group of researchers led by Dr. Gopal Murali from Ben-Gurion University of the Negev (BGU) in Beersheba, currently at University of Arizona, tried to tackle this problem.

They used species data for most land-vertebrate species (33,548 species of amphibians, birds, mammals and reptiles) regarding recent exposure to maximum temperatures to predict the effects of future extreme temperatures by the end of the 21st century. Species’ current distribution ranges and projections of future climates under different emission scenarios were used.

Dr. Takuya Iwamura from the University of Geneva who was another co-author of the paper stressed: “Our results based on daily temperature prediction show that substantial greenhouse gas emissions cuts will still enable us to minimize the effects of global warming on species survival. Following the Paris Agreement’s goal of limiting average global warming to 1.5 degrees Celsius by the end of the century will greatly prevent thousands of species from being exposed to dangerous levels of extreme heat conditions.”

They found that while thousands of species are likely to be exposed to future heat waves, the number of exposed species is much higher under high-emissions scenarios when compared to a scenario that reduces our dependence on fossil fuels.

“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,” Murali said.

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

Study coauthor Prof. Shai Meiri of Tel Aviv University (TAU) added, “As with other efforts to map human threats across all land vertebrates, we show that amphibians and reptiles are much more at risk. This is probably due to their overall smaller distribution ranges – which in our case may prevent them from escaping to regions within their distribution not exposed to extreme temperatures. As opposed to previous notions, the climate crisis is likely to also greatly affect species in the drier regions of the world including deserts, shrublands, and grasslands across North America, Africa and Australia.”

BGU’s Prof. Uri Roll, who also researched, said there are important implications in this study for biodiversity conservation. “We need to start considering the impacts of extreme heat events when making conservation and land management decisions.”