WASHINGTON (Reuters) - Carbon dioxide emissions that contribute to global warming are also turning the oceans more acidic at the fastest pace in hundreds of thousands of years, the National Research Council reported on Thursday.

Clouds move over a resort island at the Male Atoll December 8, 2009. REUTERS/Reinhard Krause

“The chemistry of the ocean is changing at an unprecedented rate and magnitude due to anthropogenic carbon dioxide emissions,” the council said. “The rate of change exceeds any known to have occurred for at least the past hundreds of thousands of years.”

Ocean acidification eats away at coral reefs, interferes with some fish species’ ability to find their homes and can hurt commercial shellfish like mussels and oysters and keep them from forming their protective shells.

Corrosion happens when carbon dioxide is stored in the oceans and reacts with sea water to form carbonic acid. Unless carbon dioxide emissions are curbed, oceans will grow more acidic, the report said.

Oceans absorb about one-third of all human-generated carbon dioxide emissions, including those from burning fossil fuels, cement production and deforestation, the report said.

The increase in acidity is 0.1 points on the 14-point pH scale, which means this indicator has changed more since the start of the Industrial Revolution than at any time in the last 800,000 years, according to the report.

The council’s report recommended setting up an observing network to monitor the oceans over the long term.

“A global network of robust and sustained chemical and biological observations will be necessary to establish a baseline and to detect and predict changes attributable to acidification,” the report said.

ACID OCEANS AND ‘AVATAR’

Scientists have been studying this growing phenomenon for years, but ocean acidification is generally a low priority at international and U.S. discussions of climate change.

A new compromise U.S. Senate bill targeting carbon dioxide emissions is expected to be unveiled on April 26.

Ocean acidification was center stage at a congressional hearing on Thursday, the 40th anniversary of Earth Day in the United States.

“This increase in (ocean) acidity threatens to decimate entire species, including those that are at the foundation of the marine food chain,” Democratic Senator Frank Lautenberg of New Jersey told a Commerce Committee panel. “If that occurs, the consequences are devastating.”

Lautenberg said that in New Jersey, Atlantic coast businesses generate $50 billion a year and account for one of every six jobs in the state.

Sigourney Weaver, a star of the environmental-themed film “Avatar” and narrator of the documentary “Acid Test” about ocean acidification, testified about its dangers. She said people seem more aware of the problem now than they did six months ago.

“I think that the science is so indisputable and easy to understand and ... we’ve already run out of time to discuss this,” Weaver said by telephone after her testimony. “Now we have to take action.”