What is Ocean Acidification (OA)?
An emerging concern about increasing carbon dioxide (CO2) emissions is ocean acidification. Ocean acidification is the reduction in the pH of the ocean caused primarily by uptake of CO2 from the atmosphere, but also caused by other chemical additions to or subtractions from the ocean (IPCC: Workshop on Impacts of Ocean Acidification on Marine Biology and Ecosystems). The world’s surface oceans are tightly linked with the atmosphere and exchange huge amounts of CO2 each year. This exchange, in part, helps to regulate the planet’s atmospheric CO2 concentrations. Over the last 250 years, the atmospheric concentration of CO2 has increased from 280 parts per million to over 394 parts per million due to the burning of fossil fuels (e.g., coal, gas, oil) and land use change (for instance, conversion of natural forest into crop production). Were it not for ocean uptake of CO2, atmospheric levels would be increasing at an even greater rate than they are now.