Narrator: But this vast ecosystem has been declining for a while. The culprit? Mass coral bleaching. As the name suggests, coral bleaching strips reefs of their color, leaving them completely white.

Record ocean heat has taken a devastating toll on one of the world’s greatest natural wonders, with coral bleaching on Australia’s Great Barrier Reef reaching “catastrophic” levels ...

It's why we've got our target to get to net zero by 2050, it's why we've legislate ... be the most spatially extensive global coral bleaching event on record. And what that means is bleaching ...

Coral at One Tree Island reef in April 2022 before the bleaching event. Credit: The University of Sydney Senior author Professor Maria Byrne on the Great Barrier Reef.