I don’t see how one can read that from “To avoid greenhouse effect you can't have things that require CO₂ to constantly remain in the atmosphere.”

The natural greenhouse effect has CO₂ constantly (I think at least since there’s any carbohydrate burning on earth) remaining in the atmosphere.

It's all implied. Maybe he doesn't know about some of those things, but it is incredibly common to talk about it in those terms without spelling out that you mean excess / problem-causing amounts of the effect, etc. When he says can't have things he's talking about human energy use. He says right after you need to use wind, solar, etc.