36% of Land Vertebrate Habitats Face Multiple Extreme Weather Events by 2085

A study led by the Potsdam Institute for Climate Impact Research and published in Nature Ecology and Evolution projects that 36 per cent of existing land vertebrate habitats will be exposed to at least two types of extreme climate events simultaneously by 2085 under a high-emissions scenario. The research analysed 33,936 terrestrial vertebrate species across 794 ecoregions and identifies the Amazon basin, Africa and Southeast Asia as the most threatened biodiversity hotspots.

By 2050, under a medium-high emissions scenario, an average of 74 per cent of species' geographic ranges is projected to be exposed to heatwaves, 16 per cent to wildfires, 8 per cent to droughts and 3 per cent to river floods. Heatwaves dominate as the primary threat, with exposure projected to increase 56 per cent above year-2000 levels. By 2050, approximately 9,434 bird, 4,729 mammal, 6,849 amphibian and 9,155 reptile species are projected to have at least 50 per cent of their geographic range exposed to heatwaves, with this figure rising further to 93 per cent above baseline by 2085.

The compounding effect of multiple simultaneous hazards is especially dangerous. A 2019-2020 Australian fire study recorded 27 to 40 per cent higher declines across flora and fauna when fire was preceded by drought compared to fire alone, demonstrating how sequential or overlapping extremes amplify impacts. Species with restricted geographic ranges face the most severe risks because they cannot shift to safer areas. The 2011 Western Australian heatwave caused a 60 per cent population decline in the Carnaby's Black Cockatoo, which experienced simultaneous high shrub and tree mortality altering habitat quality across the species' range.

The study identifies 22 ecoregions where more than 50 per cent of the area is already exposed to at least two types of extreme climate events by 2050, rising to 236 ecoregions by 2085. Wildfire hotspots are concentrated in the Amazon, southern Africa and Southeast Asia, while strong increases in flood exposure are projected for localised areas in Central Africa, taiga and tundra. The authors highlight that adaptive responses vary by species: gorillas drink more frequently at higher temperatures, while amphibians face particular risks from desiccation. Meta-analyses indicate native species show higher vulnerability to extreme events than non-native species.

Key figure — 36% of land vertebrate habitats exposed to multiple extreme events by 2085