In previous reports, risk assessed from the literature was generally based on estimates of overall range contractions with climate change. In AR4, extinction risk was carefully quantified: 'There is medium confidence that approximately 20-30% of species assessed so far are likely to be at increased risk of extinction if increases in global average warming exceed 1.5-2.5ºC . As global average temperature increase exceeds about 3.5°C, model projections suggest significant extinctions  around the globe.' These estimates approximately correspond to 50-80% reductions in range size , that this assessment equates with a 'high' and 'very high' extinction risk, respectively . AR5 stated: 'a large fraction of terrestrial and freshwater species face increased extinction risk under projected climate change during and beyond the 21st century, especially as climate change interacts with other pressures ' . A series of multi-species and global analyses have been published since AR5, using both statistical models and trait-based approaches.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report