WEST PALM BEACH, Fla. - Coral reefs are dying, and scientists and governments around the world are contemplating what will happen if they disappear altogether.
The idea positively scares them. Coral reefs are part of the foundation of the ocean food chain. Nearly half the fish the world eats make their homes around them.
Hundreds of millions of people worldwide - by some estimates, 1 billion across Asia alone - depend on them for their food and their livelihoods.
If the reefs vanished, experts say, hunger, poverty and political instability could ensue.
"Whole nations will be threatened in terms of their existence," said Carl Gustaf Lundin of the International Union for the Conservation of Nature.
Numerous studies predict coral reefs are headed for extinction worldwide, largely because of global warming, pollution and coastal development, but also because of damage from bottom-dragging fishing boats and the international trade in jewelry and souvenirs made of coral.
At least 19 percent of the world's coral reefs are already gone, including some 50 percent of those in the Caribbean. An additional 15 percent could be dead within 20 years, according to the National Oceanic and Atmospheric Administration. Old Dominion University professor Kent Carpenter, director of a worldwide census of marine species, warned that if global warming continues unchecked, all corals could be extinct within 100 years.