I think the answer to your question is that the CO2 has been absorbed by the ocean's carbonate buffer system thus far and it's capacity to do this has either al

I think the answer to your question is that the CO2 has been absorbed by the ocean's carbonate buffer system thus far and it's capacity to do this has either already been compromised in the recent past or is likely to be exceeded soon because the change in ocean pH is killing the sensitive lifeforms that are responsible for fixing CO2 as insoluble carbonates.