"We can predict the magnitude of the acidification based on the evidence that has been collected from the ocean's surface, the geological and historical record, ocean circulation models, and what's known about ocean chemistry," continued Caldeira. "What we can't predict is just what acidic oceans mean to ocean ecology and to Earth's climate. International and governmental bodies must focus on this area before it's too late."
The pH (potential of Hydrogen) scale is from 1 to 14, with 7 being neutral. Anything that lowers pH makes the solution more acidic. The scientists calculated that over the past 200 years, the pH of the surface seawater has declined by 0.1 units, which is a 30% increase in hydrogen ions. If emissions of CO2 continue to rise as predicted by the Intergovernmental Panel on Climate Change's IS92a scenario, there will be another drop in pH by .5 units by 2100, a level that has not existed in the oceans for many millions of years. In addition, the changes in the oceans' chemistry will reduce their ability to absorb CO2 from the atmosphere, which in turn will accelerate the rate of global warming.
"This report should sound the alarm bells around the world," remarked Chris Field, director of the Carnegie Department of Global Ecology. "It provides compelling evidence for the need for a thorough understanding of the implications of ocean acidification. It also strengthens the case for rapid progress on reducing CO2 emissions."