Let's be very clear here:
1) oceans are *basic* not acidic. Reducing pH of oceans at this point is *neutralization*, not acidification;
2) ocean pH varies orders of magnitude more than any proposed amount of neutralization:
"It turns out that far from being a stable pH, spots all over the world are constantly changing. One spot in the ocean varied by an astonishing 1.4 pH units regularly. All our human emissions are projected by models to change the world’s oceans by about 0.3 pH units over the next 90 years, and that’s referred to as “catastrophic”, yet we now know that fish and some calcifying critters adapt naturally to changes far larger than that every year, sometimes in just a month, and in extreme cases, in just a day."
It could be an indication that the compensation effect of the oceans is coming at an end.
How can you possibly assert that as an explanation? Let's assume, for the moment, that the missing sink is the oceans (rather than say, increased plant life, or some other part of the carbon cycle we don't understand) - the moderator of how much CO2 they could absorb every year must be the amount of surface area of the oceans, yet without changing the surface area of the oceans, you're asserting that they magically figured out how to absorb *more* CO2 in later years?
Please, *why* would the oceans in 1980 absorb x CO2 from the atmosphere, but then in 2014, they absorb Y > 10x?
Possible suggestion: Absorption of oceans is driven by ocean temperature, and from say, 1980 - 2014, increasing ocean temps absorbed more CO2 from the atmosphere. So then what regulates ocean temperature? Cloud albedo and solar activity primarily, with maybe some minuscule contribution from underwater vulcanism. Sadly, we've got no model linking cloud albedo to CO2, or solar activity to CO2, much less human CO2.
In any case, the fact that natural CO2 absorption has varied so greatly over the years indicates some other moderator than human CO2 emissions on final global CO2 levels.