I would love to see your basis for claiming this, because I don't believe a word of it.
My personal take is that, as population declines, we eventually won't be able to produce birth control pills (or plastic, if you believe that microplastics are the cause). A couple generations after that, the population decline will halt.
> Technological stagnation (no new advancement) in fewer than 50.
This I could at least see. Society requires a certain level of specialization in order to advance, and that requires a certain number of people. More technologically advanced societies may get by with fewer people, but there's still a lower limit, below which technological progress halts (or at least massively slows down).
> Sure. Imagine that central Africa (the only place with positive fertility rates) somehow never changes in that regard. What will happen? Will they be able to power the entire world's population replacement...
Yeah , total fertility is dropping worldwide, and is only barely above the replacement rate (https://ourworldindata.org/grapher/children-born-per-woman?c...). I expect it to drop into negative territory soon.
> ...they who made no AIDS medicines of their own. They make no John Deere tractors. No industry at all, really. Will they even be able to feed these people they are creating?
I think their high fertility rate has a lot to do with them being poor and underdeveloped. And there are serious ethical challenges with keeping them that way so those populations and provide the rest of the world with needed workers.
Once they hit higher levels of development, their fertility rate will decline like everywhere else. There's no getting around this without dealing directly with the fertility problems western-style development causes.
> That's not even the argument. The argument is, why isn't everyone terrified that we're well below the replacement rate (where population neither grows nor shrinks), and that we could raise it back up to the replacement rate if we wanted to.
I think it's ideological. A lot of people hold very dear to many of the social changes that have fueled the drops in fertility, and to admit that fertility rates are a problem means admitting their ideology is wrong (and perhaps their opponents are right). A lot of people are so focused on winning these short term ideological fights, they see everything in terms of them.
Also there's also the hangover from the previous overpopulation scare(s). It's hard to shift your outlook based on new data.
Sure. Imagine that central Africa (the only place with positive fertility rates) somehow never changes in that regard. What will happen? Will they be able to power the entire world's population replacement, they who made no AIDS medicines of their own. They make no John Deere tractors. No industry at all, really. Will they even be able to feed these people they are creating?
I think once the developed world goes extinct, so too they.
>There's nothing particularly sinister going on either
Functional human extinction in 120 years, absolute human extinction in 350 (or fewer). Technological stagnation (no new advancement) in fewer than 50.
>very little reason for reproducing above replacement rate.
That's not even the argument. The argument is, why isn't everyone terrified that we're well below the replacement rate (where population neither grows nor shrinks), and that we could raise it back up to the replacement rate if we wanted to.