In order to achieve this, though, we desperately need to get every country well below replacement-level fertility rate, and sustain that for a long, long time. Not sure it's possible, particularly when some political factions still consider "below replacement" to be a bad thing.
It's happening though. Birthrate in many countries are below replacement rate, and birthrates in all countries have declined:
https://www.economist.com/interactive/briefing/2025/09/11/hu....