Great Barrier Reef: Severe Coral Bleaching Hits Two-Thirds Of Reef, Aerial Surveys Show

ABC News


Aerial survey shows extent of coral bleaching

Two-thirds of the Great Barrier Reef has now been devastated by severe coral bleaching, with damage occurring further south this year, Queensland scientists say.

Two of the world's leading experts on coral bleaching in the Great Barrier Reef said aerial surveys they conducted this year along the reef's entire length showed an accelerated rate of bleaching in the central section.
The ARC Centre of Excellence for Coral Reef Studies undertook the aerial surveys in both 2016 and 2017.
In 2016, bleaching was most severe in the northern third of the Reef, while one year on the middle third has experienced the most intense coral bleaching.

The main areas of coral bleaching in 2016 and 2017. (Supplied: ARC Centre for Excellence for Coral Reef Studies)

Dr James Kerry from James Cook University in north Queensland, who was one of the scientists involved in the surveys, said the latest damage had occurred in a stretch from Cooktown to Townsville.
"Last year we saw severe bleaching in the northern third, and this year we have seen severe bleaching on the Great Barrier Reef from about Cooktown down to Townsville, so we are calling that the central third," he said.
"So about two-thirds of the reef now in the past 12 months have had a fairly serious bleaching event."
He said there was little doubt that bleaching was being caused by record-breaking temperatures driven by global warming.
"It is fair to say that this is extremely concerning for the long-term health of the reef," he said.
"It is facing a number of stresses, but I think the outside stress is coral bleaching, and we have now seen two major events in two years, which we have never seen before - that is unprecedented."
He said it was the fourth time the Great Barrier Reef had bleached severely.
"In 1998, 2002, 2016, and now in 2017 - bleached corals are not necessarily dead corals, but in the severe central region we anticipate high levels of coral loss," he said.

"It takes at least a decade for a full recovery of even the fastest growing corals, so mass bleaching events 12 months apart offers zero prospect of recovery for reefs that were damaged in 2016."

Coupled with the 2017 mass bleaching event, Tropical Cyclone Debbie struck a section of the Great Barrier Reef in March.
Scientists said the intense, slow-moving system was likely to have caused varying levels of damage along a path up to 100 kilometres in width.
Researchers said any cooling effects related to the cyclone were likely to be negligible in relation to the damage it caused, which unfortunately struck a section of the reef that had largely escaped the worst of the bleaching.

Footage shows areas of the Great Barrier Reef in the Whitsundays devastated by Cyclone Debbie (ABC News)

Links

• Cyclone Debbie leaves Whitsundays reefs in ruins
• Experts call for Australia to take lead on saving Great Barrier Reef
• Extreme heat pushes parts of Great Barrier Reef beyond recovery
• Coral Crisis: The Great Barrier Reef Needs Us To Speak Up
• Shed A Tear For The Reefs
• Coral Reefs' Only Hope Is Halting Global Warming, Study Says
• Year-On-Year Bleaching Threatens Great Barrier Reef’s World Heritage Status
• Great Barrier Reef Bleached For Unprecedented Second Year Running
• 'Significant Event': Coral Bleaching Returns To The Great Barrier Reef
• Images Of New Bleaching On Great Barrier Reef Heighten Fears Of Coral Death