ROBERT SIEGEL, host:
A major new survey of the world's coral reefs finds they are in big trouble. The reefs' survival is in doubt because the world's oceans are getting warmer and more acidic.
And as NPR's Richard Harris reports, humans are to blame.
RICHARD HARRIS: Coral reefs are spectacular ecosystems, overflowing with diverse and colorful marine life. They're also the source of food and economic sustenance to half a billion people around the world.
Lauretta Burke from the World Resources Institute is on a scientific team that has just finished measuring their health.
Dr. LAURETTA BURKE (Senior Associate, Coastal Ecosystems, World Resources Institute): Currently, we find 75 percent of the world's reefs are threatened by the combination of local and global threats. By 2030, the percentage will rise to 90 percent. By 2050, virtually all reefs will be threatened.
HARRIS: Many of the risks are familiar and longstanding. At a news conference today, Burke talked about overfishing, runoff of sewage and sediments from the shore.
Dr. BURKE: But perhaps the most shortsighted threat to reefs is the use of destructive fishing practices: The use of poisons to stun and capture fish, the use of explosives to kill fish.
HARRIS: The report also folds in global threats. Greenhouse gases pouring into the atmosphere from our tailpipes and chimneys warm the oceans, causing heat stress to corals. Lots of that carbon dioxide also dissolves in the ocean, creating carbonic acid, which can eventually corrode coral and other shell-building animals. Add it all together and Nancy Knowlton from the Smithsonian Institution says one-third of all coral species are at risk of extinction.
Ms. NANCY KNOWLTON (Coral Reef Biologist, Smithsonian Institution): This makes corals the most endangered animal on the planet, even more endangered than frogs, which have gotten a lot of press because of the diseases that have wiped out a lot of frog populations.
And, of course, this is just the corals. It doesn't really count all the things that depend on corals.
Dr. BURKE: These are dire projections.
HARRIS: Again, Lauretta Burke. She says it doesn't have to be this way.
Dr. BURKE: These results assume no improvement in management, no reduction in local threats, and that we continue on our current trajectory of greenhouse gas emissions.
HARRIS: And that current emissions trajectory does give us a small grace period says Nancy Knowlton.
Ms. KNOWLTON: The tipping point comes sometime between about 2040 and 2050, which is not that far away.
HARRIS: Local threats are potentially easier to deal with, and there has been some progress in that regard. For example, President George W. Bush created vast marine protected areas in the Pacific to preserve reefs in U.S. territorial waters.
Ms. KNOWLTON: We obviously need more marine protected areas. Not just big ones like these, but also small ones, local ones like - has been mentioned, in the Philippines and elsewhere in the developing world where major marine protected areas are not financially possible, but small marine protected areas can do a lot of good.
HARRIS: In releasing this report today, the World Resources Institute got help from one of the premiere marine biologists in this country, Jane Lubchenco, who now runs the National Oceanic and Atmospheric Administration.
Ms. JANE LUBCHENCO (Head, National Oceanic and Atmospheric Administration): It will take a Herculean effort to reverse the current trajectory and leave healthy ocean ecosystems to our children and grandchildren.
HARRIS: Nobody sounded too optimistic about that task.
Richard Harris, NPR News.