What is Ocean Acidification (OA)?
Another emerging concern about increasing carbon dioxide (CO2) emissions is ocean acidification. Ocean acidification primarily describes a change in ocean chemistry, including a reduction in pH, which results from an imbalance between the accelerating uptake of atmospheric CO2, and the ocean’s ability to resist this change. Other chemical additions to or subtractions from the ocean can also be important at local and regional scales (e.g. sulfur dioxide, excess nutrient input). The world’s surface oceans are tightly linked with the atmosphere and absorb huge amounts of CO2 each year. This exchange, in part, helps to regulate the planet’s atmospheric CO2 concentrations but it comes at cost for the oceans. Over the last 250 years, the atmospheric concentration of CO2 has increased from 280 parts per million to over 400 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.