Coral bleaching: Fourth global mass stress episode underway - US scientists

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.

Ocean heat records have been falling for months but this is the first global evidence of how this episode is affecting sea life.

The US National Oceanic and Atmospheric Administration (NOAA) confirmed the mass stress in all oceans (the Atlantic, Pacific and Indian Ocean) after weeks of receiving reports from scientists globally.