Scientists Forecast an Altered Ocean

SCIENCE -- February 23, 2011 at 4:56 PM EDT

Scientists Forecast an Altered Ocean

At the National Press Club Wednesday morning, scientists showed a video of an ocean teeming with wildlife: colorful coral, crabs, sea anemone and bright orange starfish.

The video underscored some not-so-new, but still sobering, news. If trends continue unchecked, our ocean may soon be robbed of its rich coral reefs and many of the 4,000 fish species that depend on them.

Some 75 percent of the world's reefs are facing the threat of extinction, and absent major changes, that number will rise to 90 percent by 2030, and reach 100 percent by 2050, according to a new analysis released Wednesday.

And reversing these trends will take a Herculean effort, NOAA Administrator Jane Lubchenko warned.

The threats to the reefs aren't new. Warming sea temperatures and rising carbon dioxide lead to mass coral bleaching and death. Overfishing, farm runoff, sewage discharge and industrial pollution are also among the top offenders. In fact, this report, a global collaboration by more 25 organizations and led by the World Resources Institute, builds on a similar report released in 1998, which cited many of the same sources.

But the latest report is far more detailed than its predecessor, and includes higher resolution maps, made possible by satellite technology.

"This report shows the power of technology and how it helps transform our understanding of the natural world," said Jonathan Lash, president of the World Resources Institute. "This is key."

An estimated one-third of all coral species are at risk of extinction, said Nancy Knowlton of the Smithsonian Institution, a longtime coral researcher. "That makes coral the most endangered animal on the planet, even more endangered than frogs," she said. "We're talking about a loss of habitat that is mega diverse in the most mega possible way."

Carbon dioxide alters the ocean chemistry. Pollution poisons and kills. Runoff carries nutrients, which can smother and clog the corals and block photosynthesis.

Scientists highlighted the benefits coral reefs provide to their nearby coastal communities. They provide a source of protein, food security, a tourism draw, and countless jobs. Some species provide ingredients for drugs to treat cancer, HIV and malaria, Knowlton said.

Against this sobering background, scientists doled out some hopeful news. The data cited are worst-scenario numbers and assume no change to pollution, overfishing and other threats. And when threats are reduced, coral reefs have been known to bounce back.

But that will require less destructive fishing, huge reductions in land pollution and greenhouse gas emissions, and changing policy priorities. In Thailand, for example, diving has been limited in six protected areas.

"If we are going to avoid that tipping point, we need people to care about reefs," Knowlton said.

Zoom In On the Map Below:

Coral reefs of the world classified by threat from local activities

Beginning October 24, 2012, PBS NewsHour will allow open commenting for all registered users. We hope that the elimination of our moderation process will enable a more organic discussion amongst you, our audience. However, if a commenter violates our terms of use or abuses the commenting forum, their comment will be removed. We reserve the right to remove posts that do not follow these basic guidelines: comments must be relevant to the topic of the post; may not include profanity, personal attacks or hate speech; may not promote a business or raise money; may not be spam. Anything you post should be your own work. The PBS NewsHour reserves the right to read on the air and/or publish on its website or in any medium now known or unknown the comments or emails that we receive. By submitting comments, you agree to the PBS Terms of Use and Privacy Policy, which include more details.