A Record Heat Wave Killed Huge Parts Of The Great Barrier Reef

The Great Barrier Reef has been dying, but scientists have now quantified just how quickly the heat and bleaching events played into that decline.

A Record Heat Wave Killed Huge Parts Of The Great Barrier Reef
Researchers document dead coral after a bleaching event at Lizard Island on the Great Barrier Reef

It's no secret the Great Barrier Reef has been dying for some time nowNew research shows just how quickly that rising ocean temperatures can destroy large swaths of coral.

In 2016, an eight-month marine heat wave kept surface temperatures in the Coral Sea about 1 degree Celsius warmer than usual. Researchers now say that slight increase caused nearly 30 percent of coral in the Great Barrier Reef to start dying.

Bleached coral reef in the Maldives

The Worst Coral Bleaching Event Ever May Be Over: Now For The Bad News

It can take years for corals to recover after just one bleaching event; some reefs around the globe experienced three.


The most catastrophic die-offs occurred where temperatures rose the highest. In those spots, coral died immediately from heat stress. Bleaching events, which are linked to warming, killed even more coral, albeit more slowly. Of the 60 percent of coral colonies that experienced heavy bleaching, only 1 percent survived after eight months.

These colonies might be able to regrow, but researchers said the chances of a full recovery are "poor." They noted that many of the survivors of this heat wave are still slowly dying because they're now more susceptible to disease and that even the fastest growing species of coral would take at least a decade to pop back up.