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Oceans and Coasts

Toxic Oceans: Scientists Propose Plan to Stop Acidification


Almost Dead

Almost completely dead reefs, covered with bacterial slime, in Papua New Guinea.

Healthy Corals

A healthy and diverse community of exposed corals.

“If we were to continue producing carbon dioxide at the rate we are now, by mid-century every coral reef in this world will stop growing. They will all be going backwards.”

Charlie Veron, coral reef expert

"There is hope for corals if we act now."

Rod Salm, director of tropical marine conservation for the Conservancy's Asia-Pacific program

By Naomi Sodetani

Increasing global carbon dioxide emissions are not just damaging the Earth’s climate, but eroding coral reefs, our rainforests of the sea.

According to scientists at the 2008 International Coral Reef Symposium, acidification is the greatest threat that oceans face today.

In response to this looming threat, the Conservancy recently convened a workshop with some of the world's leading climate and marine scientists and coral reef managers to come up with ways to help coral reefs worldwide survive ocean acidification.

The meeting led to the Honolulu Declaration, an action plan that includes:

Acidification Causes "Osteoporosis of the Reef"

“The reefs of the world are at risk,” says Rod Salm, director of tropical marine conservation for the Conservancy’s Asia-Pacific program and presenter of the Honolulu Declaration at the August 27 U.S. Coral Reef Task Force meeting.

Corals, says Salm, are increasingly besieged by the “triple threat” impacts brought on by climate change — rising sea levels, temperatures and now, ocean acidification.

How does more carbon dioxide in the air impact marine resources?

The ocean absorbs about one-third of atmospheric carbon dioxide, which dissolves in seawater. This causes an increase in acidification and a decrease in the amount of carbonate available for corals and other calcifying marine organisms, like plankton and mollusks, to build their skeletons.

An acidic environment makes corals brittle and weaker, crippling their ability to grow, reproduce and resist disease. A disturbing aspect of this threat is its invisible stealth. Unlike mass bleaching, acidification is difficult to detect.

“Ocean acidification is creeping, progressive and insidious — like osteoporosis of the reef — a weakening of the reef structure that makes corals more vulnerable to breakage from waves and human use,” Salm told the task force.

Scientists Fear Corals Could Be Gone

A decade ago, Joan Kleypas, a scientist with the National Center for Atmospheric Research, had warned of the effects of increased atmospheric carbon dioxide on marine life.

“It is clear that seawater chemistry will change in coming decades and centuries in ways that will dramatically alter marine life,” said Kleypas, a workshop participant who signed the Honolulu Declaration.

John “Charlie” Veron, widely respected as the world’s foremost coral reef expert, also took part in the workshop and signed the declaration. Over his 40-year career, Veron has identified a quarter of the world’s coral species, tracing their evolution back tens of millions of years. He now fears for their demise.

”There’s no point in spending a lot of time researching a new species when I know it’s going to go extinct,” Veron says. His most recent book, A Reef in Time: The Great Barrier Reef from Beginning to End (2008, Harvard University Press), is his Silent Spring for the world’s coral reefs.

“If we were to continue producing carbon dioxide at the rate we are now” — a rate unprecedented on this planet, says Veron — “by mid-century every coral reef in this world will stop growing. They will all be going backwards.”

The Honolulu Declaration is a “wake up call to say how serious, how urgent it is – but also say, let’s do something about it,” Veron stresses, “because it can be avoided.”

Is There Hope for Our Corals?

Like a ticking time bomb, scientists say that much of the carbon already spewed into the atmosphere will further acidify our oceans for decades to come.

“While the consequences of inaction are too depressing and terrifying to contemplate, there is good news,” says Salm.

He notes that the landmark “meeting of minds” created a solid foundation for a new era of coral reef conservation, and that action steps proposed by the group, if quickly enacted, will help to save coral reefs from escalating destruction.

The Honolulu Declaration presents seven policy and eight management recommendations.

"There is hope in what came out of our workshop because we have come up with practical steps people can take that are not hugely costly and will not marginalize progress made," Salm says.

The most practical policy is to mandate that climate change actions, including those addressing rising ocean acidification, sea level and temperatures, be included in marine protected management plans, he says.

According to Salm, we also need to put all efforts possible into reducing stresses on reef systems — stresses from people, boats, overfishing, pollution and other destructive impacts.

The less stressed corals are, the more healthy and resilient they will be and better able to respond to climate changes, says Salm.

The Honolulu Declaration will be presented to the United Nations and other global, regional and national forums to obtain government commitments to address the acidification challenge.

"I think it's very encouraging," Salm adds. “I just hope we're able to buy time for coral reefs while carbon dioxide levels are stabilized and, eventually, rolled back and contained.”

“There is hope for corals if we act now."

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