Consequences: Widespread destruction of coral reef ecosystems and dependent socio-ecological systems. Three mass bleaching events from 2016 to 2020 have already caused significant loss of corals in shallow-water habitats across the GBR. Globally, bleaching is projected to occur twice each decade from 2035 and annually after 2044 under RCP 8.5 and annually after 2051 under RCP4.5. A 3ºC global warming could cause over six times the 2016 level of thermal stress. Hazards: Increase in background warming and marine heatwave events degrade reef-building corals by triggering coral bleaching events at a frequency greater than the recovery time. Fish populations also decline during and following heatwave events. Exposure: Increasing geographic area affected by rate and severity of ocean warming Vulnerability: Vulnerability to increases in sea temperature is already very high because of other stressors on the ecosystem, including sediment, pollutants and overfishing. Adaptation options: Minimising other stressors. Efforts on the GBR may slow the impacts of climate change in small sections or reduce short-term socioeconomic ramifications, but they will not prevent widespread bleaching.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report