Last Thursday, the Center for Biological Diversity sued the federal government to force the EPA to regulate ocean acidification under the Clean Water Act. 

Ocean acidification may cause as much harm as global warming, and yet neither the Environmental Protection Agency nor any of the 50 states in the U.S. regulates ocean acidification as they would other water pollutants. Why not?

The Atlantic suggests a few possible reasons. First, we have known about the greenhouse effect longer than we have known about ocean acidification. Second, it is difficult to measure ocean acidification. And third, even if the EPA could determine that a body of water were harmed by ocean acidification, it can't control CO2 emissions in the air -- which are the cause of ocean acidification. 

Still scientists have some ideas about how to start analyzing -- and combating -- acidification.