Harmful bleaching of the world’s coral has grown to include 84% of the ocean’s reefs in the most intense event of its kind in recorded history, the International Coral Reef Initiative announced Wednesday.

A global coral bleaching episode has hit 84% of the world's coral reefs, making it the worst bleaching event recorded in history, according to a report by the International Coral Reef Initiative released Wednesday.

An unprecedented coral bleaching episode has spread to 84 percent of the world's reefs in an unfolding human-caused crisis that could kill off swathes of the essential ecosystems, scientists warned