Climate warming has dealt yet another blow to the Great Barrier Reef

Australia’s Great Barrier Reef is experiencing its sixth massive bleaching event as climate change has warmed the ocean, raising concerns over whether one of the world’s natural wonders is nearing a tipping point.

Reef managers confirmed Friday that aerial surveys detected catastrophic bleaching on 60 percent of the reef’s corals. The discovery is particularly disturbing, researchers said, because a cooling La Niña weather pattern in the ocean usually offsets warming that stresses coral and causes them to lose color.