Carbon Dioxide is a One-Way Street

Actually the formation of coal was not due to the lack of bacteria but the lack of oxygen. A lot of the ancient forests were actually swamps and the excess water covered the foliage, preventing aerobic fermentation or decomposition. You can see examples of this in fresh water tropical areas today. The water looks like strong tea.

Bacterium's are among the oldest and most successful organisms on the earth. Just because certain types need oxygen doesn't make them less plentiful.

If you perform a search of CO2 on this site you will find a lot of discussions about this subject. The problem seems to boil down to a critical race between plant an animal life. When the animal life creates more CO2 than it can tolerate, the plants will win and the next mass extinction will mostly affect the animals (including us). But fear not, because that won't likely happen in your lifetime. Can it really be stopped? Well, could the dinosaurs that were masters of the earth for more than 100 million years do anything about giant asteroids? I think you know the answer.