There are a lot of people who will hear CO2 and immediately decide they don't believe you. There's been some bad science behind global warming that deniers will latch onto, and I suspect "CO2" will just get associated with that in many people's minds. The science behind (and the effects of) ocean acidification are far more sound, IMHO. Probably wouldn't be bad to get a second chance in many people's minds at presenting the data.
Of course, I'm sure the same people may latch on to this as "the problem is all fixed".
Of course, I'm sure the same people may latch on to this as "the problem is all fixed".