> By the time birth rates plummet below replacement rate in Africa, they would have risen well above replacement again in Europe and North America.
What makes you think they will rise again in a timely manner? Demographers naively predicted the rates would stop decreasing and magicaly stabilize close to replacement levels, and failed miserably. To my best knowledge there is no indication the current trends will reverse or at least stabilize any soon.
Demographers were kinda right, it's just that we've had new socioeconomic problems [0][1] post-pill, and we're really starting to feel the effects since around 2008. Post-pill fertility rates in Europe and NA had been slowly rising before that. I think we're likely to fix at least one of these problems in the coming decades. Or rather, we have to because we'd be royally screwed otherwise. And in the event we fail, most democratic societies would turn authoritarian, in which case they'd be able to implement population engineering measures like banning birth control.
What makes you think they will rise again in a timely manner? Demographers naively predicted the rates would stop decreasing and magicaly stabilize close to replacement levels, and failed miserably. To my best knowledge there is no indication the current trends will reverse or at least stabilize any soon.