The numbers are extremely counter-intuitive because we live far longer than we're fertile. Imagine we have a society that starts with 100 newborns with a fertility rate of 1, in a world where everybody gives birth at 20 and dies at 80. To make this 'sim' slightly more realistic, I'm also going to add in some filler population in year 0 with the assumption of a 6 fertility rate. Incidentally this is exactly the case for South Korea which went from greater than 6 to less than 1 in an incredibly brief period of time:
---
(148) Year 0: 4 sixties, 11 forties, 33 twenties, 100 newborns <=== last year of 6 fertility rate, ~3:1 youth:elder generation ratio
(194) Year 20: 11 sixties, 33 forties, 100 twenties, 50 newborns <=== start of 1 fertility rate
In spite of having an extinction level fertility rate, everything just seems perfectly peachy at first. The initial population is even seeing some very healthy increases over decades. As the high fertility group starts to die the growth sputters, but it seems less than catastrophic. But then when the generation that's failed to replace itself starts dying, it's like a bomb goes off. Suddenly the population is getting chopped in half every 20 years to say nothing of a large elder population now being supported by a smaller than ever youth population.
In South Korea (and most of the world, including the US) the key initial inflection is between 1960 and 1980 where they went from greater than 6, to less than 2 fertility, which is now less than 1. So their 'great dying' event will start sometime around 2060. So far away, yet also so predictable - and with 0 doubt of its certainty unless something changes dramatically now. And that seems unlikely.
Most social services function something like a pyramid scheme. You need more people paying in than taking out.
There are ways to tweak the balance a bit, almost all of which have to do with finding efficiencies that reduce administrative costs- replacing in person visits with doctors with video calls to nurses, moving manual-process-intensive paperwork to less-manual-intensive electronic billing, that sort of thing.
Unfortunately, there's only just so much you can do when a greater percentage of the population is drawing on benefits and not working than there are people working and paying taxes. If the balance swings too far, something has to give- rationing access by adjusting age limits, declining certain types of care, reducing benefits, that sort of thing.
Sure, but making people take social security at 75 instead of 65 or whatever is hardly the civilization annihilation event the person upthread was describing.
---
(148) Year 0: 4 sixties, 11 forties, 33 twenties, 100 newborns <=== last year of 6 fertility rate, ~3:1 youth:elder generation ratio
(194) Year 20: 11 sixties, 33 forties, 100 twenties, 50 newborns <=== start of 1 fertility rate
(208) Year 40: 33 sixties, 100 forties, 50 twenties, 25 newborns
(187) Year 60: 100 sixties, 50 forties, 25 twenties, 12 newborns <==== last high fertility elder dies, start of new 1:2 youth:elder generation ratio
(93) Year 80: 50 sixties, 25 forties, 12 twenties, 6 newborns
(46) Year 100: 25 sixties, 12 forties, 6 twenties, 3 newborns
(23) Year 120: 12 sixties, 6 forties, 3 twenties, 1 newborn
---
In spite of having an extinction level fertility rate, everything just seems perfectly peachy at first. The initial population is even seeing some very healthy increases over decades. As the high fertility group starts to die the growth sputters, but it seems less than catastrophic. But then when the generation that's failed to replace itself starts dying, it's like a bomb goes off. Suddenly the population is getting chopped in half every 20 years to say nothing of a large elder population now being supported by a smaller than ever youth population.
In South Korea (and most of the world, including the US) the key initial inflection is between 1960 and 1980 where they went from greater than 6, to less than 2 fertility, which is now less than 1. So their 'great dying' event will start sometime around 2060. So far away, yet also so predictable - and with 0 doubt of its certainty unless something changes dramatically now. And that seems unlikely.