Food supplies will run short, tourism will be hit and coastal communities affected as the world's coral reefs gradually decline under climate change, scientists say.
The reefs already were dying at an increasing rate because of global warming and acidification of the oceans, said researchers meeting this week at the International Coral Research Symposium (ICRS) in Fort Lauderdale, Florida.
Chair of the climate change session, Professor Ove Hoegh-Guldberg (Ove Hoegh-Guldberg) of the ARC Centre of Excellence for Coral Reef Studies in Townsville, said there was evidence that all coral reefs were in trouble.
"The evidence suggests reef systems are becoming more brittle, as a result of bleaching, disease and the effects of acidifying water," he said today.
"This means we are likely to see more moonscape-like areas where reefs once used to be.
"This will be accompanied by a switch from the spectacularly colourful fish that people normally associate with reefs to much fewer and plainer ones."
Prof Hoegh-Guldberg said around 500 million people, mainly in developing countries, depended on coral reefs for food and their livelihoods and developed countries used them as a tourism drawcard.
But weakened coral would no longer provide enough protection against the threat of storm surges and tsunamis, particularly with rising sea levels.
"This will be accompanied by murkier, less productive waters as water quality suffers."
Professor Hoegh-Guldberg said researchers had found evidence that the rate at which coral reefs have been deteriorating and disappearing had accelerated in the past five years.
"For the past 30 years, the loss has been between one to two per cent of the world's coral per year," he said.
"The latest data suggest that the rate is now around two per cent a year. This doesn't give us much time.
"If we continue on the pathway that we are on right now, we get to levels where you are looking at the total loss of reef structures worldwide."
Urgent action was needed to cap the use of oil, gas and coal contributing to global warming, he said.
"With no other solutions in front of us, then it would be foolhardy and unethical for us not to consider these urgent actions."
