Carbon dioxide is a main contributer to the Greenhouse Effect, and when more and more of it is added to the atmosphere, it can have lasting severe consequences and repurcussions.
Greater carbon dioxide emissions into the atmosphere would dramatically increase its concentration and heat the atmosphere, the ocean, and the planet in general.
When the world becomes more overpopulated than it already is, housing, food, freshwater, and other resources will become more scarce and expensive to obtain for the ever-growing human species.