The oceans are acidifying more quickly than at any time in hundreds of thousands of years, the National Research Council has reported to Congress.
The report adds that unless man-made CO2 emissions are substantially cut or atmospheric CO2 is controlled by some other means, the acidification will accelerate.
The ocean absorbs around a third of man-made CO2 emissions, decreasing its pH. Since the beginning of the industrial revolution, the average pH of ocean surface waters has fallen from about 8.2 to 8.1. Models project a further 0.2 to 0.3 drop by the end of the century.
This rate of change is the fastest in hundreds of thousands of years, the committee told Congress.
Studies on marine organisms have shown that lowering seawater pH with CO2 affects photosynthesis, nutrient acquisition, growth, reproduction, and individual survival.
It damages shell and skeletal growth in many creatures, including reef-building corals, commercially important mollusks such as oysters and mussels, and several types of plankton at the base of marine food webs.
And there still isn’t enough information to assess the social or economic effects of ocean acidification, much less develop plans to mitigate or adapt to them, the NRC noted.
The federal government has already steps to respond to the nation’s long-term needs by creating the National Ocean Acidification Program.