A plan conceived on O'ahu to save the world's coral from "osteoporosis of the reef" was introduced yesterday at the World Conservation Congress in Spain.

The scientists who wrote the Honolulu Declaration on Ocean Acidification and Reef Management hope the gathering of 8,000 environmental leaders will adopt their suggestions, said Rod Salm of The Nature Conservancy.

"Our goal is to raise awareness of ocean acidification and what can be done about it," said Salm, who was among 14 U.S. and Australian scientists who created the action plan during an Aug. 12-14 workshop on O'ahu.

"Coral reefs are at the heart of our tropics, and millions of people around the world depend on these systems for their livelihoods," said Lynne Hale, director of The Nature Conservancy's Marine Initiative.

"Without urgent action to limit carbon dioxide emissions and improve management of marine protected areas, even vast treasured reefs like the Great Barrier Reef and Northwestern Hawaiian Islands will become wastelands of dead coral," she said in a statement.

Hale presented the Honolulu Declaration yesterday to the conference in Barcelona, Spain, said Salm, who is the conservancy's director of Asia-Pacific Tropical Marine Conservation.

Another of the scientists who created the declaration, Joan Kleypas of the National Center for Atmospheric Research, called ocean acidification "osteoporosis of the reef" because it weakens the reef structure much as the human disease weakens bones, Salm said.

The Honolulu Declaration is two-pronged. It urges lower fossil fuel emissions, because carbon dioxide absorbed into the ocean is a major factor in the increasing seawater acidity since the Industrial Revolution. And it calls for management of the world's coral reef ecosystems to help them survive climate changes that will continue even if the world reduces greenhouse gas emissions.

In simple terms, Salm said, the carbon in carbon dioxide forms carbolic acid in seawater, which prevents corals from growing by using calcium in the seawater. And when the acidity of seawater reaches a certain point, it actually dissolves the calcium component of a reef.

"The best evidence we have suggests that when atmospheric carbon dioxide levels reach 560 parts per million, many reefs will already have moved from net growth to net erosion," Salm said in a synopsis of the Honolulu Declaration.

In the 650,000 years before the Industrial Revolution, carbon dioxide concentrations in the atmosphere were between 200 and 280 parts per million, Salm said. Current levels are about 385 parts per million.

"These days, 'pristine' needs to be retired from the dictionary," said Salm, who has studied coral reefs worldwide for 40 years. "Everywhere, reef ecology has been hit — directly by people or increasingly by climate change."

While the world struggles to lessen greenhouse gas emissions, Salm said, "It's crucial to identify reefs that are naturally less vulnerable to acidification because of the chemistry of the water around them."

Those reefs, if preserved, could act as the refuges for coral species that could repopulate other areas if the ocean acidification trend is reversed.