Climate change intensifies climate extremes globally, threatening biodiversity. Vertebrates vulnerable to climate extremes are identified by the International Union for Conservation of Nature (IUCN), though future changes in exposure to climate extremes for these species remain unclear. Using CMIP6 climate models under four Shared Socio-economic Pathways, we projected changes in extreme drought, heat, and precipitation frequencies globally between 1974–2014 and 2050–2090 for 1,634 terrestrial vertebrates considered threatened by climate extremes, focusing on 33 global vertebrate diversity hotspots. Results indicate substantial increases in climate extremes, with tropical regions facing the highest increases in extreme heat and drought. Hotspots with few climate extreme-threatened vertebrates often face the highest increases in climate extreme frequencies, suggesting vertebrate vulnerability within numerous hotspots is understudied. These results highlight the need to incorporate climate projections into conservation assessments, and for targeted research on climate extreme effects on tropical vertebrates, which may have lower tolerances to climatic change than temperate counterparts.

We used global standardized precipitation index (SPI) and temperature data to calculate past and future climate extreme occurrence. To this end, we used four Global Climate Models (GCM) and four Representative Concentration Pathways (RCP), for a historical and future period, from CMIP6 projections.  We analyzed changes in drought exposure across species ranges considered by IUCN to be threatened by three types of climate extremes, and across 33 global vertebrate diversity hotspots holding about 85% of global vertebrate diversity.