“You seem knowledgeable about carbonate equilibria and the ocean. Is there any evidence that the ocean is actually becoming more acid”
I know only what I read on the internet. ;-)
The ‘ocean acidification’ is actually a claim that the ocean will go from 8.1 pH to ... 7.8 pH. BFD!
I learned up on the topic here:
http://www.seafriends.org.nz/issues/global/acid.htm
One word why ocean acidification is not a problem: CALCIUM.
(The ocean has a lot of it, and it buffers the acidification like a TUMS will cure your acid stomach).
“It is thought that the carbondioxide in the sea exists in equilibrium with that of exposed rock and bottomsediment containing limestone CaCO3 (or sea shells for that matter). In other words, that the element calcium exists in equilibrium with CO3. But the concentration of Ca (411ppm) is 10.4 mmol/l and that of all CO2 species (90ppm) 2.05 mmol/l, of which CO3 is about 6%, thus 0.12 mmol/l. Thus the sea has a vast oversupply of calcium. It is difficult therefore to accept that decalcification could be a problem as CO3 increases. To the contrary, it should be of benefit to calcifying organisms. Thus the more CO2, the more limestone is deposited. This has also been borne out by measurements (Budyko 1977). “
That sounds like a significant decrease, but I would like to see real observational data, not the prediction of someone’s “modeling.” We’ve all seen how the AGW crowd finagle the data to make their models give the right result. Anyway, there are lots of mechanisms which take up CO2. Something like 1/4 or more of the land surface of the U.S. is underlain by limestone, which takes up CO2 as it weathers. Weathering of silicate rocks does also, but usually at a slower rate. Then of course there is photosynthesis and solution of CO2 in the oceans.