Great Barrier Reef: 93% of reefs hit by coral bleaching

Comprehensive aerial survey reveals full extent of the devastation caused by abnormally warm ocean temperatures

Almost 93% of reefs on the Great Barrier Reef have been hit by coral bleaching, according to a comprehensive survey revealing the full extent of the devastation caused by abnormally warm ocean temperatures sweeping the globe.

There have only been three mass bleaching events recorded on the reef , and all of them have happened since 1998. Scientists say this episode is the worst they've ever seen.