Despite covering approximately 2% of the Earth's land area, islands harbour more than 20% of extant terrestrial species . Islands have disproportionately higher rates of endemism and threat when compared to continents, with 80% of historical extinctions  having occurred on islands  . Current climate change projections suggest that insular species are particularly sensitive and, even at mild warming levels, substantial losses are expected  . Given islands' characteristic high endemicity, current high threat levels and the fact that islands host almost half of all species currently considered to be at risk of extinction, especially at higher warming levels  , further losses could contribute disproportionately to global biodiversity decline  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report