The world's coral reefs could be wiped out by 2050 unless urgent action is taken to stop threats posed to the "rainforests of the sea" by everything from overfishing to global warming, a report warned on Wednesday.
Warmer seas caused by global warming; ocean acidification blamed on carbon dioxide pollution; shipping, overfishing, coastal development and agricultural runoff all pose a threat to coral reefs, which hundreds of millions of people depend on for a living, says the report.
"If left unchecked, more than 90% of reefs will be threatened by 2030 and nearly all reefs will be at risk by 2050," says the "Reefs at Risk Revisited" report, which was compiled by dozens of research, conservation and educational groups led by the World Resources Institute think-tank.
"Local pressures" on reefs, including overfishing, coastal development and pollution, pose the most immediate and direct threats to the world's reefs, threatening more than 60% of the colorful sea "forests" in the short term, the report says.
The impacts of climate change -- a "global threat" to reefs -- is compounding the local pressures.
"Warming seas have already caused widespread damage to reefs, with high temperatures driving a stress response called coral bleaching, where corals lose their colorful symbiotic algae, exposing their white skeletons," the report says.
"In addition, increasing carbon dioxide (CO2) emissions are slowly causing the world's oceans to become more acidic. Ocean acidification reduces coral growth rates and, if unchecked, could reduce their ability to maintain their physical structure."
Losing the coral reefs would deprive millions of coastal dwellers of a key source of food and income, and would deprive shorelines of protection from storms, the report says.
There would be fewer nurseries for commercial fish species, and less sand on tourist beaches if coral reefs are destroyed.
"We need to improve, quickly and comprehensively, on existing efforts to protect reefs," says the report, which is aimed at galvanizing the world into action "to save these critical ecosystems."