The future scenario is very likely global population crash due to both fiscal and food chain collapse. It’s not like we can prevent this with voluntary measures like birth control or going to vegetarian diets. It has to be all-out carbon fuel reduction and regenerating global forests to even have a hope for a future for everyone.
Having said that, even before collapse, it’s soon going to be too expensive and dangerous to bring children into the world for typical families. I think the best we can do is make birth control universally available, educate women, and not subsidize with public policy more than 2 kids for each woman. Vasectomies should be universally provided, and child support made absolutely mandatory. Abortion has to be universally legal, but not promoted as a first means of birth control. Our economic system will shift, with the most money going to containing and repairing damages from climate change and shortages, with the remaining assets going towards declining consumption by humans. We’re upending the growth pyramid, necessarily so, and this will fundamentally change our society as well. The best thing that can be said about it is that wars for oil will be over, it will be over food and water.