It's not just a "set back", it's a fantasy. There's a hundred times too many people on this Earth to live like that. We've leveraged up our population using technology, and there's no way to unwind that without also eliminating almost everyone. Nor would we want to. Say what you will about the ills of technology, but I'm so much happier to be living now than a hundred years ago. Life is better by nearly every way you want to measure it. We'll have to get ourselves out of the climate mess the same way we got into it - with technology.