There is no evidence that any acceptable behavioral alteration will help. The kind of behavioral modification needed is horrifying dystopian nightmare stuff, people naturally resist things like that. The population is going to be reduced no matter what. The question is purely "are we going to do it by lowering birth rates, or are we going to wait until India or Africa unleashes an antibiotic resistant super plague on the world that kills a few billion people?"
Rethinking our property system need not be draconian. The economic solutions to a steady state economy have been on the shelf for years. The ideology of growth will need a humiliating defeat, and then folks will be ready to accept alternatives.
The ideology of growth being dealt a genuinely humiliating defeat would involve massive depopulation event anyway. It seems far better to shift away from growth-dependent economics before any humiliating defeat rather than hope the people who survive it happen to be well-versed in regenerative economics.
I've started a meetup group for the purpose of discussing how a grassroots effort could shift some of the resources of the growth-economy to a steady-state economy while the former is still in place, but interest has been miniscule in my midsized college town.
That's stopping growth, that's what I am suggesting we do. The alternative which I think can only be draconian is "modifying our behavior" to accommodate a huge population. This means eliminating almost all food in favor of the half dozen highest producing crops. It means eliminating all natural spaces and consuming all resources for ourselves and leaving nothing for non-humans. I can't see any reason why a high population is a good thing, much less so good that it warrants making all those lives as miserable as possible. A billion people with high quality of life and a diverse planet full of billions of creatures beats the hell out of a hundred billion people living like factory farmed chickens on a planet virtually devoid of non-human life.
