Reversing population growth means having an ever increasing population of elderly people and increased burden on the young to support those elderly. It's hard to see solutions to this that aren't dystopian and downright cruel.
Wealth-wise, the global bottom 50% emit on average 1.4 tonnes of carbon-dioxide equivalent (tCO2e) per year. The top 10% emits 28.7 tCO2e [1].
We're not talking about billionaires when we mention "the top 10%. This was a 2019 study, so 10% of the population was about 770 million people— that's roughly the population of the whole of Europe [2].
That bottom 50% deserve their living standards to be elevated. They deserve and should get sewage, home appliances, water pipes, electricity, cars, meat, video games, disposable income, etc etc. When that happens, half of the population could be producing one or two orders of magnitude more tCO2e. Someone in that 10% right now is producing 205x more tCO2e than someone in that bottom 50%, and it isn't because they own private jets, it's because they can afford a washer and dryer.
[1]: https://www.nature.com/articles/s41893-022-00955-z#:~:text=G...).
This assumes that technology remains constant.
As it stands now, technology is not catching up and a smaller percentage of them will have access to those amenities.
We can't just create more oil out of thin air. Progress on batteries is too slow and renewables and electric cars are too expensive. We're already over-fishing and over-farming the earth with our current population. We are missing all of our climate targets, and that's on an earth where most don't live in developed countries yet.
We could replace those needs with technology like VR experiences and processed food for example, but I have a hard time seeing how that will be enough.
Industry that serves a number of individuals, so the relationship is direct.