Coral bleaching hits 75 per cent of Great Barrier Reef

The Great Barrier Reef is is in the grip of its fifth mass bleaching event in eight years. (HANDOUT/THE UNDERTOW OCEAN & DIVERS FOR CLIMATE)

Coral bleaching driven by climate change has hit three quarters of the Great Barrier Reef, with 50 per cent suffering high or very high levels of damage.

The reef is in the grip of its fifth mass bleaching event in eight years due to heat stress fuelled by the burning of fossil fuels.