Tour boat divers have long borne witness to mass bleaching events. Once reluctant to wade into discussions about global heating, they are now opening up

“You can see it on their faces,” says scuba diving instructor Elliot Peters. “There’s definitely some remorse and sadness.”

Peters works at a resort on Heron Island in the southern part of the Great Barrier Reef and, in recent weeks, he’s had to tell curious guests why so many of the corals around the island are turning bone white.

The reef is in the middle of its fifth mass bleaching event in only eight years – an alarming trend driven by global heating in a year that has seen record global ocean temperatures.

Peters has never seen a mass coral bleaching event up close before, but this summer he’s seen ancient boulder corals that can live for hundreds of years bleaching and showing signs of death.

“If anything it’s motivating me,” he says. “It’s opening the doors to get people talking about climate change and the health of the reef. People are thanking us for telling the truth about what’s going on here.”