A third of the habitats currently occupied by land animals across the world could be exposed to multiple climate-driven extreme events such as heatwaves, wildfires, droughts and floods by 2085 if greenhouse gas emissions continue to rise, according to a new international study published in Nature Ecology & Evolution.
The research, led by the Potsdam Institute for Climate Impact Research (PIK) in Germany, analysed projected risks for 33,936 terrestrial vertebrate species, including amphibians, birds, mammals and reptiles, using climate impact models and species range data. It found that under a medium-high emissions scenario, 36% of the area within species’ current geographic ranges could be exposed to at least two different types of extreme events by 2085.
That would mark a sharp rise from 2050, when 14% of habitats are projected to face multiple extremes.
Lead author Stefanie Heinicke, a postdoctoral researcher at PIK, said the conservation risks from climate extremes are still underestimated. “Climate change, and in particular extreme events, are still really being underestimated when it comes to conservation planning. It’s not just going to be a gradual shift of temperature over many years,” she said.
The study warns that even a single heatwave, drought or wildfire can devastate wildlife populations, but back-to-back or overlapping disasters can be even more damaging. It cites evidence from Australia’s 2019-20 megafires, where areas that had already suffered drought recorded 27-40 pc greater declines in plant and animal species.
Among individual hazards, heatwaves emerged as the dominant threat. By 2050, an average of 74 pc of land animal habitats could be exposed to extreme heatwaves under the same emissions pathway. Wildfires were the second-largest threat, affecting 16% of habitats, followed by droughts at 8% and river floods at 3 pc.
By 2085, heatwave exposure could rise to 93 pc of species’ ranges, while wildfire exposure may increase to 25 pc, drought to 14 pc, and floods to 5 pc.
The impacts are expected to hit biodiversity-rich regions particularly hard, including the Amazon basin, tropical Africa and Southeast Asia, where many species already face habitat destruction and fragmentation. Mid-latitude ecosystems are also projected to see a steep rise in combined extremes. The study found that the number of global ecoregions with at least half their area exposed to two or more extreme event types could jump from 22 regions in 2050 to 236 by 2085.
Researchers noted that some species can adapt to natural disturbances, and certain ecosystems depend on periodic fires or floods. However, the speed and intensity of climate-driven extremes may exceed the ability of many species to cope, especially those with small geographic ranges.
The study also found that rapid emission cuts could significantly reduce future damage. Under a low-emissions pathway aligned with the Paris Agreement (SSP1-2.6), only 9 pc of species’ habitats would face multiple extremes by 2085, compared with 44% under a very high emissions scenario.