Maps showing computer model simulations of present-day ocean pH (left) and two possible futures: one in which we quickly and significantly reduce carbon dioxide emissions (middle), and one in which we do not (right). Because the pH scale is logarithmic, a difference of one pH unit represents a tenfold increase or decrease in acidity. Based on model data publsihed in Bernie, D., J. Lowe, T. Tyrrell, and O. Legge (2010), Influence of mitigation policy on ocean acidification, Geophys. Res. Lett., 37, L15704, doi:10.1029/2010GL043181.