ABC News Online, Posted Fri Dec 19, 2008 2:46pm AEDT
Updated Fri Dec 19, 2008 3:05pm AEDT
Predictions of a long, hot summer may please many Australians, but it is not good news for one of the country's top tourist attractions.
Satellite images show sea surface temperatures in the Coral Sea are already higher than average and the Bureau of Meteorology and the American National Oceanic and Atmospheric Administration have both forecast a high risk of coral bleaching.
Dr Russell Reichelt, the chairman of the Great Barrier Reef Marine Park Authority, says scientists are comparing this year's summer to another devastating time for the world's reefs.
"They're likening the conditions that we're looking at this summer now to be same as they were in 1998, when a very large global event occurred where 16 per cent of the world's coral reefs died from coral bleaching," he said.
Half of the Great Barrier Reef was affected by coral bleaching in that year, but only 5 per cent suffered permanent damage.
Dr Reichelt says reefs can recover from bleaching if they do not face further stresses from pollution, over-fishing or repeated hot weather events.
"Things like poor water quality running off the land should be cleaned up," he said.
"Things like damaging ... from anchoring on corals should be prevented.
"We want a healthy reef to be able to withstand the pressures that are happening from global warming."
Professor Terry Hughes, the director of the Australian Research Council Centre of Excellence for Coral Reef Studies, says if the warmer temperatures persist for more than two months there is a serious risk of coral dying.
"If you lose the structure that the corals provide through their skeleton then fish populations inevitably decline as well," he said.
No 'distant threat'
Professor Hughes says bleaching is a clear sign of global warming.
"It's important to remember that for coral reefs, global warming is not some distant threat that might or might not happen in the future," he said.
"It's already happening.
"The Great Barrier Reef has already bleached twice and there's a very good chance that this year will be the third major bleaching event."
Environment groups accuse the Federal Government of ignoring the reef in its response to climate change this week.
"What would be a horrible irony of the release of the emissions trading system targets this week would be to see a taste of things to come in the future, of more severe and frequent bleaching events," Richard Leck, from conservation group WWF Australia, said.
"That's what will happen unless we get action on climate change - significant reductions, not 5 per cent reductions."
Professor Hughes says unless CO2 emissions are sharply reduced, the Great Barrier Reef will be lost.
"We've got 10 to 15 years to significantly reduce CO2 emissions," he said. "We need to do better."
However, scientists say a cyclone or winds could cool water temperatures this summer and prevent a major bleaching event.
Based on a report by Jennifer Macey for AM, December 19.