The University of Queensland's Centre for Marine Studies is predicting that Australia's Great Barrier Reef will lose 95 percent or more of its living coral by mid-century as a result of global warming.
The Intergovernmental Panel on Climate Change forecasts that global warming will increase sea temperatures by between 2.7 and eight degrees Fahrenheit this century. Even at the lower end of this limit, “there will be much more frequent coral bleaching events and coral will become quite rare—down to five percent of current levels for all of the Great Barrier Reef,” says report co-author Ove Hoegh-Guldberg.
The new report, commissioned by World Wildlife Fund and the Queensland government, considers “thermal stresses” on the reef—sustained temperatures that exceed corals' tolerance, causing mass bleachings and coral death. “By about 2050, the thermal threshold of all corals in the reef will be exceeded,” says Hoegh-Guldberg.
But other scientists disagree. “Global warming is obviously a concern, but it makes it sound as though we're certain to lose the reef and I don't think we can say that at all,” says Peter Ridd, who has studied physical and environmental impacts on the reef at James Cook University in Queensland.