New York Times, Opinion Pages
Since the beginning of the industrial era, humans have pumped increasing amounts of carbon dioxide into the atmosphere. This has led not only to a warmer climate but also to significant changes in the chemistry of the oceans, which have long acted as a sink for carbon emissions but are being asked to absorb more than they can handle. The result is ocean acidification: increasingly corrosive seawater that has already ruined many coral reefs and over time could threaten the entire marine food chain.