Group urges fast action to curb acidity of oceans

NEW YORK - The oceans have long buffered the effects of climate change by absorbing a substantial portion of the greenhouse gas carbon dioxide. But this benefit has a catch: as the gas dissolves, it makes sea water more acidic.

Now an international panel of marine scientists says this acidity is accelerating so fast it threatens the survival of coral reefs, shellfish, and the marine food web generally.

The panel, comprising 155 scientists from 26 countries and organized by the United Nations and other international groups, is not the first to point to growing ocean acidity as an environmental threat, but its blunt language and international credentials give its assessment unusual force.

"Severe damages are imminent," the group said yesterday in a statement summing up its deliberations at a symposium in Monaco last October. It called for "urgent action" to sharply reduce emissions of carbon dioxide.

The statement, called the Monaco Declaration, said increasing acidity is interfering with the growth and health of shellfish and corals.

Already, the group said, there have been detectable decreases in shellfish, shell weights, and interference with the growth of coral skeletons.

Jeremy B.C. Jackson, a coral researcher at the Scripps Institution of Oceanography in San Diego, said "there is just no doubt" that the acidification of the oceans is a major problem.

Oceans absorb about a quarter of carbon dioxide emissions, and the acidity of ocean surface waters has increased by 30 percent since the 17th century, the researchers said.

The group said acidification can be controlled only by limiting future atmospheric levels of the gas.

Other strategies, including "fertilizing" the oceans to encourage the growth of tiny marine plants that take up carbon dioxide, might make the problem worse in some regions, it said.