IPCC Fourth Assessment Report: Climate Change 2007 Climate
Change 2007: Working Group I: The Physical Science Basis Box 7.3
Figure 1  Box 7.3, Figure 1. (a) Atmospheric CO2 emissions,
historical atmospheric CO2 levels and predicted CO2
concentrations from the given emission time series, together
with changes in ocean pH based on horizontally averaged
chemistry. The emission time series is based on the mid-range
IS92a emission scenario (solid line) prior to 2100 and then
assumes that emissions continue until fossil fuel reserves
decline. (b) Estimated maximum change in surface ocean pH as a
function of final atmospheric CO2 pressure, and the transition
time over which this CO2 pressure is linearly approached from
280 ppm. A: Glacial-interglacial CO2 changes; B: slow changes
over the past 300 Myr; C: historical changes in ocean surface
waters; D: unabated fossil fuel burning over the next few
centuries. Source: Caldeira and Wickett (2003). Reprinted with
permission from Macmillan Publishers Ltd: Nature, Caldeir