Carbon Dioxide Levels Increase Ocean Acidity

According to Britain's leading scientific organization, the Royal Society, carbon dioxide is making the world's oceans increasingly acidic. The Royal Society has released 60 page report to coincide with the Group 8 economic meeting this week. The group's current president, Prime Minister Tony Blair, has called for action to slow climate change.

http://www.nytimes.com/2005/07/01/international/europe/01ocean.html

The effects of the increase can be measured now.

Unlike forecasts of global warming, which are based on complex and incomplete computer models, *the chemistry of carbon dioxide and seawater is simple and straightforward*.

The burning of fossil fuels by cars and power plants releases more than 25 billion metric tons of carbon dioxide into the air each year. *Roughly a third of that is absorbed by the oceans, where the gas undergoes chemical reactions that produce carbonic acid, which is corrosive to shells*.

Substantial change has already taken place in the last two hundred years.

Ocean water today is somewhat alkaline, at 8.1, *about 0.1 lower than at the start of the Industrial Revolution two centuries ago*.

But like the magnitude scale of earthquakes, *one unit on the pH scale reflects a change of a factor of 10. The 0.1 pH change means there are now 30 percent more hydrogen ions in the water*.

Depending on the rate of fossil fuel burning, *the pH of ocean water near the surface is expected to drop to 7.7 to 7.9 by 2100, lower than any time in the last 420,000 years*, the Royal Society report said.

While there have been times in the distant past where carbon dioxide levels have been high, the concern is that the current change is taking place too fast. That is, a slower increase would allow the oceans to dilute the additional carbon dioxide.

Dr. Ken Caldeira, a research scientist at the Carnegie Institution's Department of Global Ecology in Stanford, Calif., and a member of the Royal Society panel:

"If we put it out over a few hundred thousand years, we'd have nothing to worry about," he said.

Coral reefs, already facing the problem of temperature change, will likely suffer further.

The pH change is likely to slow the rate of growth of coral reefs, which are already suffering from warmer temperatures and pollution, the report said.