I grew up worried that the world's population would grow too much and widespread hunger would result.
But I think 2026 is the year there will be a move to a long term drop in the world's population.
By this I mean that
1. World fertility will continue to decline at the same rate as it has been recently. So TFR of 2.3 in 2023 going to 2.25 2024, 2.20 2025, 2.15 in 2026.
2. Infant and child mortality will decline at the same rate as it has been recently. It is down to about 3.5% from 9.7% in 1990. Malaria, TB and other vaccines might reduce this considerably but fairly slowly and not much by 2026.
3. Sex selective abortion will continue to decline but not fast enough to keep females being born above replacement level.
Long term it is number of women that are raised per woman that matters. If our life expectancy goes from 40 to 80 to 120 that's really good for us. And it will mean the world's population goes up. But not in the long term.
Long terms it is really women that matter. They are the ones that actually have children. Obviously this men not mattering idea is not true at the extreme end. You do need some men.
Assuming life expectancy and men do not matter. What does matter in particular is number of female children per woman. And particularly how many of those live to an age when they can have children.
And I think these align so that we move below replacement level in 2026.
The year of peak births seems to have been 2013 and to have moved to below long term replacement that soon afterward is quite surprising. Getting the exact year is hard as in some ways we won't know how many people get to the age they can have children until they get there. At a 1% yearly decline in fertility we will be below replacement birth level soon.
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