Australia's famous Great Barrier Reef could be dead within decades because of the effects of global warming, according to a leaked report.
The reef is a huge tourist attraction
The report, from the Intergovernmental Panel on Climate Change (IPCC), warns that the reef's coral could be bleached because of warmer seas.
IPCC scientists are meeting in Paris, and are due to release the first stage of their findings on Friday.
The Barrier Reef is Australia's leading tourist destination.
The draft comments, obtained by The Age newspaper, come from the second report which the IPCC will publish this year, dealing with impacts of climate change; the first reviews the overall scientific picture.
The draft document warns that the Great Barrier Reef will become "functionally extinct" because of coral bleaching - which occurs when the animal organisms that make up the coral die, leaving behind a white limestone skeleton.
GREAT BARRIER REEF
More than 2,000 km long
Home to 1,500 types of fish
Only living thing the naked eye can see from space
Bleaching occurs regularly during periods when water becomes unusually warm.
Many reefs in East Asia declined significantly during the El Nino conditions in 1997/8; it can take a decade for coral to start recovering from severe bleaching.
But in the future, the Barrier Reef may not have the chance to recover, scientists warn, as temperatures continue to rise and the sea becomes more acidic. This raises the risk that the coral will die outright.
The reef attracts a million visitors a year, and is home to sharks, turtles and numerous brightly coloured fish.