Carbon dioxide doesn't have any hydrogen. Therefore, it can't increase the acidity of oceans. In contrast, sulfuric and nitric acid fully dissociate in water.
How gullible does someone have to be to believe that carbonic acid is a cause and not an effect of increasing ocean acidity?
The main problem with coal is sulfur. This causes acid rain. Why don't people concerned about the environment call for the decommissioning of coal power plants, rather than making bogus claims about CO2? Most coal power plants are nearly 50 years old anyway, so it's not much of a loss from an economic perspective. Note, the shelf life of a coal power plant is about 50 years.