Legislating outcomes would mean having to compel you. If you want to guarantee that you, personally, will be net-zero CO2, then the government will need some wa

Legislating outcomes would mean having to compel you. If you want to guarantee that you, personally, will be net-zero CO2, then the government will need some way to enforce that guarantee. I'm not sure that's really what you want. There wouldn't be any room to say, "I wanted to be net-zero, but I couldn't force the local power company to stop using coal". You'd either have to cut your energy use, a lot, or suffer whatever punishment was in the government's purview. This is a coordination problem. That's precisely the kind of situation that governments are good for.