Carbon dioxide making oceans more acidic
The world’s oceans are becoming more acidic as they absorb more carbon dioxide, a study by researchers from the Lawrence Livermore National Laboratory (LLNL) has found.They attribute this to increasing emissions of carbon dioxide from burning fossil fuels. The higher the emissions to the air, the higher the amount absorbed by seawater. Once in the sea, it reacts to form carbonic acid, raising the acidity levels of the water.
Oceanic absorption of carbon dioxide was originally viewed as beneficial as it removed greenhouse gases from the atmosphere. However, using computer models, Dr Ken Caldeira and Dr Michael Wickett, calculated that the continued production of carbon dioxide at current rates would increase ocean acidity more rapidly than during the past 300 million years, resulting in damage to marine life.
Scientists believe that the oceans have already become slightly more acidic over the last century. This study, however, has tried to predict what will happen in the future by combining information about the history of the oceans with computer models of climate change.
“We predicted amounts of future acidity that exceed anything we saw over the last several hundred million years, apart from perhaps after rare catastrophic events such as asteroid impacts,” Dr Caldeira said.
Previous studies have shown that marine organisms such as coral reefs, calcareous plankton and other sea life with calcium carbonate skeletal material are likely to be harmed by increasing ocean acidification. They find it much more difficult to build these structures in water with a lower pH.
LLNL is conducting research to understand how this acidity could be neutralised, with one option using crushed limestone to absorb some of the acid. The lab is also studying ways of storing carbon dioxide underground and investigating the use of hydrogen, fusion and other approaches for environmentally acceptable energy sources.