Ocean acidification: a millennial challenge

During recent decades, Earth system research has provided overwhelming evidence that climate change, with disastrous consequences, will result from unbridled anthropogenic emissions of greenhouse gases. It is well accepted among climate scientists that these emissions, especially of CO2, may force the planet to warm by up to seven degrees C by the end of the century. During recent years, however, a second comparably dangerous consequence of steadily increasing atmospheric carbon dioxide levels has received growing attention, namely the acidification of the oceans. Here we discuss its potential effects on marine biogeochemistry and review the recent literature on this issue. Calcifying organisms such as corals, pteropods, coccolithophorides and foraminifera are among the species that will suffer most from unabated ocean acidification.