No more or less than usual.
Recent journal articles and media headlines have used “more” or “increasing” with “acid” as a root for a supposed lowering of the average pH of the oceans from 8.2 to 8.1. I say, “supposed,” because Sverdrup et al. (1963) state, “The pH encountered in the sea is between about 7.5 and 8.4.” Elsewhere, they say, “The pH of water in contact with the air will vary between about 8.1 and 8.3, depending upon the temperature and salinity of the water and the partial pressure of carbon dioxide in the atmosphere.” Similarly, the well-known Stanford geochemist Konrad Krauskopf (1967) states, “The pH of ocean water sampled near the surface is almost always between the narrow limits of 8.1 and 8.3. Locally and temporally it may deviate from this range, but by and large the pH stays surprisingly constant.” Thus, the claimed recent decline to an average pH of 8.1 from 8.2 is within the bounds of the typical range observed more than 50 years ago. Further, the claim has been made that the average pH of the oceans in pre-industrial times was 8.2; yet values as high as 8.3 were reported commonly 50 years ago. Thus, it would seem that neither the claimed values of 8.1 currently, or 8.2 150 years ago are credible.
If you want to get deep in to the weeds on the chemistry (and the misleading media language-and its roots) read the entire article here.
