Watch: Coral turns white from deadly ocean heat
Coral around the world is turning white and even dying as recent record ocean heat takes a devastating toll.
It has triggered the fourth global mass coral bleaching event, according to the US National Oceanic and Atmospheric Administration (NOAA).
Bleaching happens when coral gets stressed and turns white because the water it lives in is too hot.
Coral sustains ocean life, fishing, and creates trillions of dollars of revenue annually.
