> You answered it yourself: it's not possible to get rid of the excess CO2. Think about conservation of energy: we extracted energy by burning stuff and producing CO2.

You can use pyrolysis to reduce usage of energy. Instead of building ethanol using corn etc, some fast growing crop can be converted to biochar using pyrolysis. And stored indefinitely underground or somewhere. Of course this isn't profitable and probably will run in to climate activists roadblocks.