If humans persist in releasing CO2 into the atmosphere at current rates, a tipping point will be reached within 10 years beyond which ocean warming will occur no matter what humans do from that point, reducing the reef's chances of survival, Ove Hoegh-Guldberg at the University of Queensland said.
Previously, biologists had thought corals might be able to handle rising ocean temperatures by exchanging the symbiotic algae they rely on for their energy with other species that can survive at higher temperatures.
Recent studies suggest this is possible for only the 25 per cent of the world's coral species that host multiple species of algae rather than just one.
The remaining species would have to "migrate their way out of trouble" instead, Hoegh-Guldberg said.
Under current rates of warming, he estimates, corals would have to move southward at a rate of 10 miles per year to stay cool.
"Individual coral larvae can travel great distances, but the entire reef system can't," he said. "The uncomfortable conclusion is that we might lose the reef."