[philipkglass]

It would be a much smaller shift if the CO2 were uniformly mixed through the whole depth of the ocean. Atmospheric CO2 concentrations are rising too rapidly for that. It takes thousands of years for the deep ocean to uniformly mix with near-surface water. The acidification effects over the "short" (decades-centuries) time scale are concentrated in the upper few hundred meters of ocean. Unfortunately, those upper few hundred meters are also where the vast majority of oceanic biological productivity are located. The acidification is worst where it's most biologically worrisome.