ahhh it doesn't work that way. Yes, Plants do breath in CO2 and breath out O2, BUT only for pary of their life cycle, then the contribute a good deal of Methane and other gasses as they break down. What they produce depends on ground water humidity and chemicals in the soil. However more CO2 is not necessarily good for existing plants and crops.
Plats growing range is dependent on temperature and weather which varies with climate. OTPH the main plant life increase we get with increased CO2 are Algae Blooms and they are not desirable and can result in large die offs of fish and other aquatic species.