US set to violate its standards on CO2 emissions

The US may violate its own standards on water quality by refusing to limit emissions of carbon dioxide, suggests a new study modelling ocean acidification.

“About one-third of the CO2 from fossil-fuel burning is absorbed by the world’s oceans,” explains Ken Caldeira at Stanford University in California, US, who led the study.

The CO2 lowers the pH of the ocean’s surface, a phenomenon known as ocean acidification. This is predicted to have dramatic consequences on marine life by dissolving the shells of tiny organisms and corals.

If governments do nothing to limit greenhouse-gas emissions, CO2 levels in the oceans will rise to a point where, by 2050, ocean acidification will reach a level considered to be industrial waste by the US’s own standards, found the study to be published on 25 September.
Industrial waste

“”We need to start thinking about carbon dioxide as an ocean pollutant,” urges Caldeira. “When we release carbon dioxide to the atmosphere, we are dumping industrial waste in the ocean.”

The US Environmental Protection Agency (EPA) water quality criteria, states that the pH of ocean waters beyond 200 metres deep should not be changed more than 0.2 units outside natural levels. Estimates put natural levels at a range from 8 to 8.25 pH. Anything beyond this is considered industrial waste. However, these standards are not enshrined in US law.

Caldeira’s team calculated how CO2 emissions from fossil-fuel burning impact on ocean acidification.
‘Dangerous interference’

“If atmospheric CO2 goes above 500 parts per million, the surface of the entire ocean will be out of compliance with EPA pH guidelines,” says Caldeira. Currently, concentrations are at 380 ppm. However, computer models suggest that if governments do nothing to limit greenhouse-gas emissions, concentrations could climb to at least 760 ppm by 2100 and could reach 500ppm by 2050.

The Kyoto protocol seeks to curb the growth of greenhouse gas emissions. The US government has repeatedly refused to ratify it. Yet, Caldeira points out that the US government has unwittingly already set itself emissions targets, in the form of the EPA’s water quality standards.

“The UN talks about avoiding ‘dangerous anthropogenic interference with the climate system’ but leaves vague what constitutes ‘dangerous interference’. The US already published a number – 0.2 pH units – with the implication that greater changes constitute dangerous interference in the marine system,” he told New Scientist.

Ne Scientist, 24 September 2007. Article.


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