Great Barrier Reef suffers severe bleaching for second year running

By AG Staff 10 April 2017
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New aerial surveys reveal two-thirds of the Great Barrier Reef have suffered severe bleaching for the second time in just 12 months.

TWO-THIRDS OF Australia’s Great Barrier Reef have been hit by a severe bleaching event for the second year running, and the window to save the World Heritage-listed natural icon is rapidly closing, experts warn.

The extent of this year’s coral bleaching has been revealed in aerial surveys covering the entire length of the reef – more than 8000km.

great barrier reef bleaching

Bleached coral off Mission Beach, Queensland. (Image: Bette Willis)

“The combined impact of this back-to-back bleaching stretches for 1500km, leaving only the southern third unscathed,” said Professor Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies.

“The bleaching is caused by record-breaking temperatures driven by global warming. This year, 2017, we are seeing mass bleaching, even without the assistance of El Niño conditions,” explained Terry, who undertook the aerial surveys in both 2016 and 2017. 

This is the fourth severe bleaching event for the Great Barrier Reef, with previous events recorded in 1998, 2002 and less than 12 months ago 2016. 

great barrier reef bleaching

Diver surveys bleached coral off Orpheus Island, 1189km northwest of Brisbane. (Image: Greg Torda)

“Bleached corals are not necessarily dead corals, but in the severe central region we anticipate high levels of coral loss,” said Dr James Kerry, who was also involved with the survey.

The reef was also hit by Tropical Cyclone Debbie in late March, which is likely to have caused varying levels of damage along a path up to 100km wide, the researchers said. 

“Clearly the reef is struggling with multiple impacts,” said Terry. “Without a doubt the most pressing of these is global warming. As temperatures continue to rise the corals will experience more and more of these events: 1°C of warming so far has already caused four events in the past 19 years.”

‘Ultimately, we need to cut carbon emissions, and the window to do so is rapidly closing,” he said.