I'm always confused why the "two kids" i.e. replacement is treated as growth. This seems to be a systemic belief.
Maybe there's something I'm missing about population dynamics, but generations are a pipeline. Yes, you're around for many years after your kids are born, but as your kids are born your grandparents or great-grandparents are probably reaching the end of their rope.
A system where a process dies as soon as it spawns a new process will have no more net growth than a system where the process sticks around for N cycles after spawning a new process, and then dies. Given the same original number of processes, it will have a greater number of processes running at equilibrium, but it will experience equilibrium nonetheless.
Not to mention, "two kids" actually leads to a very gentle decline (because not everyone reproduces) which is reasonably socially stable, unlike a world in which fertility is 0.2 per couple.
Replacement-level total fertility rate is actually generally accepted to be a little bit above 2 (around 2.3), due to unnatural deaths and other causes. At least in Geography.
With only two kids per couple, even if every woman had 2 children (which is what a 2.0TFR would mean), the population would still decline.
Maybe there's something I'm missing about population dynamics, but generations are a pipeline. Yes, you're around for many years after your kids are born, but as your kids are born your grandparents or great-grandparents are probably reaching the end of their rope.
A system where a process dies as soon as it spawns a new process will have no more net growth than a system where the process sticks around for N cycles after spawning a new process, and then dies. Given the same original number of processes, it will have a greater number of processes running at equilibrium, but it will experience equilibrium nonetheless.
Not to mention, "two kids" actually leads to a very gentle decline (because not everyone reproduces) which is reasonably socially stable, unlike a world in which fertility is 0.2 per couple.