Stanford, CA. -- In a commentary in the September 25, 2007, issue of the Geophysical Research Letters (GRL), a large team of scientists state that human-induced carbon dioxide (CO2) emissions will alter ocean chemistry to the point where it will violate U.S. Environmental Protection Agency Quality Criteria  by mid-century if emissions are not dramatically curtailed now. This is the first recognition that atmospheric CO2 emissions will cause ocean waters to violate EPA water quality criteria.
The paper also says that carbon-dioxide induced changes in ocean chemistry within the ranges predicted for the next decades and centuries present significant risks to marine biota and that adverse impacts on food webs and key biogeochemical process would result.
An international team of twenty five leading researchers described the evidence to date regarding the effects of CO2 emissions on the acidity of the worlds oceans.
About 1/3 of the CO2 from fossil-fuel burning is absorbed by the worlds oceans, explained lead author Ken Caldeira from the Carnegie Institution Department of Global Ecology. When CO2 gas dissolves in the ocean it makes carbonic acid which can damage coral reefs and also hurt other calcifying organisms, such as phytoplankton and zooplankton, some of the most critical players at the bottom of the worlds food chain. In sufficient concentration, the acidity can corrode shellfish shells, disrupt coral formation, and interfere with oxygen supply.
Most of the research today points to a future where, in the absence of a major effort to curtail carbon dioxide emissions, there will be double the atmospheric concentrations of CO2 (760 parts per million, or ppm) by centurys end. Atmospheric carbon dioxide concentrations could reach 500 ppm by mid-century. Pre-industrial concentrations, by comparison, were 280 ppm and today's concentration is about 380 ppm.
The acidity from CO2 dissolved in ocean water is meas
|Contact: Ken Caldeira|