Projected effects of global warming on coral reefs in seas close to Japan

Abstract

Global warming and associated increases in water temperature is considered to be a crucial factor for future corals, by inducing coral habitat migration toward higher latitudes and intensifying chances for coral bleaching and death. Using projected monthly-mean sea surface temperature in the 21st century, we quantitatively evaluate the potential effects of global warming on corals in seas close to Japan. Our result shows that the temperature-determined northern limit of subtropical coral reefs, which is currently located in the southern Kyushu, is expected to migrate northward, up to the northern Kyushu, and that the northern limit of coral habitat, currently located in Niigata and Chiba Prefectures, is estimated to go up to Aomori and Iwate Prefectures, by the end of the 21st century. In the Ryukyu Islands, on the other hand, both frequency and area of coral bleaching or death are expected to be intensified. Particularly, intermittently experienced high water temperatures which result in bleaching or death of present-day corals, will appear perpetually in the latter half of the 21st century.