The Great Barrier Reef's coral could disappear in as little as 20 years as sea temperatures rise faster than expected, a world expert on coral and climate change has warned.
Professor Ove Hoegh-Guldberg, director of the Centre for Marine Studies at the University of Queensland, says bleaching will occur and coral will die regardless of what happens in the battle against global warming.
"It is shocking to wake up and realise we really are in a desperate time," he said. "We may see a complete devastation of coral communities on the reef and a major change to the pristine values, which at the moment are our pride and joy.
"We are likely to see corals rapidly disappear from great parts of the Barrier Reef, as it has already from large parts of the Caribbean."
The warning comes as The Age begins a three-part series on the Kyoto Protocol, which becomes international law on Wednesday.
Marine scientists are closely watching the coral, hoping the widespread bleaching of 1998 and 2002 are not repeated. In 1998, 16 per cent of the world's coral died after rising sea temperatures caused mass bleaching on almost every reef.
"We now have less time left," said Professor Hoegh-Guldberg. "Across the globe we should be rallying around as though we are facing a confrontation like a world war."
Coral has a small tolerance for rises in sea temperatures. A rise of one degree means that the tiny algae that live in the coral polyps are expelled, leaving coral white or "bleached". If this happens repeatedly, or for long periods, the coral dies.
Most scientists now agree that greenhouse gases from industry, electricity use and cars have caused the planet to warm 0.6 degrees in the past century. Because the gases can live in the atmosphere for 50 to 200 years, another increase in warming is already locked in, regardless of action on cutting back pollution.
The latest figures from NASA say this warming - if we stopped all emissions as of today - will be an extra 0.6 degrees by 2030, bringing the global average rise to at least 1.2 degrees. Many scientists are discussing how greenhouse gases may be stabilised to halt warming at two degrees above the long-term average. The most pessimistic scenario from the United Nations sees a warming of 5.8 degrees by the century's end.
"There are impacts in the pipeline, due to the inertia of the climate system. In 20 years' time, bleaching is highly likely to be annual and that will cause shallow-water corals to be in decline," said Professor Hoegh-Guldberg, who is leading a $20 million study into coral bleaching mostly funded by the World Bank
