Ranging from 0 to 14, pH is a scale that describes the acid and base properties of a solution. The ocean's surface has an average pH of around 8.1, which is slightly basic. The pH of the open ocean is relatively stable in both time and space; however, the uptake of CO2 by the ocean has caused measurable changes in seawater. The imagery here shows the output of a computer model that makes predictions of how the pH will change over time based on best estimates of likely CO2 emissions (RCP 8.5) used in the United Nations Intergovernmental Panel on Climate Change's AR5 assessment. The dataset starts in 1861 and runs through 2100
Although the pH changes appear small, pH is on a log scale meaning that a change of one unit represents an order of magnitude change in the acidity of the seawater. Ocean acidification, a lowering of ocean pH, has the potential to significantly impact marine ecosystems by the end of this century.