In the Southeast Asia region threats from both warming and acidification has indicated that by 2030, 99% of reefs will be affected, and by 2050, 95% are expected to be in the highest levels of the 'threatened' category , similar to global corals . Modelling results indicate that even under RCP scenarios, the functional traits of coral reefs can be affected  and coral communities will mainly consist of small numbers of temperature-tolerant and fast-growing species . Increases in temperature  and pCO2  projected for this century can reduce the sperm availability for fertilisation, which along with adult population decline either due to climate change or anthropogenic impacts  can affect coral reproductive success thereby reducing the recovery of populations and their adaptation potential . In the southern Persian Gulf, increased disturbance frequency and severity has caused progressive reduction in coral size, cover and population fecundity , and this can lead to functional extinction. Connectivity required to avoid extinctions has increased exponentially with disturbance frequency and correlation of disturbances across the metapopulation. In the Philippines experiments have also proved that scleractinian corals, such as A. tenuis, A. millepora and F. colemani, which spawn their gametes directly into the water column, may experience limitations from sperm dilution and delays in initial sperm-egg encounters that can impact successful fertilisation .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report