Emeritus Professor Clifford Ollier writes at QUAESTIONES GEOGRAPHICAE: "The oceans are not acid, never have been in geological history, and cannot become acid in the future. Changes in atmospheric CO2 cannot produce an acid ocean. Marine life depends on CO2, and some plants and animals fix it as limestone. Over geological time enormous amounts of CO2 have been sequestered by living things, and today there is far more CO2 in limestones than in the atmosphere or ocean. Carbon dioxide in seawater does not dissolve coral reefs, but is essential to their survival."