Large swaths of wildlife habitats around the world are likely to be hit by multiple extreme climate events by 2050, according to a new paper in the journal Nature Ecology and Evolution — with the size of the impact determined, in large part, by how quickly the world cuts emissions.
Using climate impact projections and species range data, scientists modeled changes in vulnerability to drought, heatwaves, river floods and wildfires for 33,936 species of terrestrial vertebrates across 794 ecoregions. By 2050, under a medium to high emissions scenario, an average of 74% of the area within species’ current geographic ranges is expected to be exposed to heat waves, 16% to forest fires, 8% to droughts, and 3% to river floods. Species-rich areas of the Amazon Basin, Africa, and Southeast Asia are among the areas most at risk.
The aggravation of these events is where the real danger lies. A single heatwave, flood or fire can devastate animal populations; When multiple extreme events follow one another, their impacts on species and habitats multiply. Heatwaves in Australia in 2019-2020 killed more than 72,000 flying foxes. In the same year, forest fires in the Pantanal region killed an estimated 17 million vertebrates. Studies of the 2019-2020 Australian fires found a greater decline of 27-40% in plant and animal species in areas that experienced drought immediately before. A review of 519 studies found that 57% documented adverse responses to extreme events, including 100 cases of population declines exceeding 25% and 31 records of local eradication.
By 2050, 22 ecoregions – mainly located in mid-latitudes – are expected to have at least half of their area exposed to two or more types of extreme events. By 2085, this number will rise to 236 ecoregions, with 36% of the species’ range areas experiencing multiple types of events.
Rapid emissions reductions could still largely prevent this path. In a scenario in which warming begins to decline in the latter part of the century, habitats exposed to multiple types of extreme events by 2085 would be limited to just 9%.
“Climate change, especially extreme events, is still underestimated when it comes to conservation planning,” said lead author Stephanie Hyneke, a postdoctoral researcher at the Potsdam Institute for Climate Impact Research. “It will not just be a gradual shift in temperature over many years.” This paper was co-authored by researchers from Karlsruhe University of Applied Sciences, Universidad del Rosario in Bogotá, the University of Tokyo and several other institutions.
The researchers relied on climate impact simulations from the Intersectoral Impact Models Comparison Project and species data from the IUCN Red List of Threatened Species, the Global Assessment of Reptile Distributions and BirdLife International.
