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.
The notion that CO2 will dissolve the shells of ocean life is totally wrong. At the beginning of the Cretaceous era, atmospheric CO2 was 2000 ppm, SIX TIMES what it is today. Yet, the Cretaceous is the period marked by the formation of thousand-foot deep limestone formations. Idiots.