Effects of Future Climate Extreme Heat Events and Land Use Changes on Land Vertebrates

Climate and land use changes pose the greatest threats to biodiversity, but their synergistic effects on biodiversity have been rarely studied. Here, we assessed the combined effects of future climate and land use changes on the world's land vertebrates (29,657 species) across four socioeconomic scenarios between 2015 and 2100. We evaluated species range exposures to extreme heat events (relative to temperatures during 1950-2005) and land use changes in species' preferred habitats. Under the best-case scenario, species will experience unsuitable conditions due to both factors across 10% of their range on average. In the worst scenario, species are projected to face unsuitable conditions across 52% of their range. By the end of the century, up to 7895 species are expected to face extreme heat events and/or unsuitable land use changes across their entire range, and thus potentially go globally extinct. The synergistic impact of climate and land use changes is most noticeable in the Sahel (e.g., Sudan, Chad and Mali), the Middle East (e.g., Afghanistan, Iraq and Saudi Arabia), and Brazil. Under two of the four scenarios, over half of all Data Deficient (> 77%), Near Threatened (> 50%), or threatened species (> 60%), will experience unsuitable conditions across at least half of their range. Our results highlight the potential detrimental effects of future environmental changes and the importance of considering and mitigating the synergetic effects of these threats on biodiversity.