Barrier Reef on death row

It could take less than 20 years for rising sea temperatures caused by global warming to kill Australia's Great Barrier Reef, the world's largest chain of living coral, a newspaper reported on Saturday.

"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," professor Ove Hoegh-Guldberg, director of the Centre for Marine Studies at the University of Queensland, told The Age.

"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 daily cited Hoegh-Guldberg as saying.

Coral bleaching - when the water temperature gets so high that it kills the algae which populate and build the corals - presents the greatest risk to the reef. Repeated or prolonged bleaching kills coral.

Australia's last major coral bleaching episode occurred in 2002 and damaged about 55% of the coral systems in the Great Barrier Reef.

Professor Hoegh-Guldberg, who headed a World Bank-funded study into coral bleaching, told The Age that the reef could be in critical danger in 20 years.

"In 20 years' time, bleaching is highly likely to be annual and that will cause shallow-water corals to be in decline," he said.

Researchers had earlier warned that the higher ocean temperatures caused by global warming could kill off most of the coral in the Great Barrier Reef by 2050.

The World Heritage-listed Great Barrier Reef stretches for almost 2 000km along most of the coast of Queensland state and is one of Australia's most popular tourist spots.