[Aerroon]

I find these predictions fascinating to think about. Did we get them right this time? I remember that we were taught about the idea of overpopulation in school. As I understand, it was believed in the 60s and 70s that the world population would keep massively increasing. People were worried about overpopulation. At this point we know that that's not true - it seems that essentially all rich countries see a decline in birthrates. They might increase in population, but it happens due to immigration. However, will this pattern hold?

As I understand it, before the industrial revolution, the population was what's described as Malthusian. As a country became richer it tended to have a population increase, which meant that an estimate of GDP per capita remained relatively similar. Over thousands of years you'd see maybe a doubling or quadrupling of it. Ie the median person in the year 500 AD lived rather similarly to the median person in the year 1500 AD.

When the industrial revolution rolled around, things changed. The estimate of GDP per capita increased faster than the population. People became richer and their lives became significantly better. This came with a substantial population increase, because people started living longer. The fruits of progress spread to poorer areas. The increase in food availability and medicine made many population counts skyrocket.

At some point during this it turned out that the richest areas started seeing a significant decrease in birthrates though. Why? I'm unsure. Perhaps people wanted better lives for their children and they couldn't afford to have as many children? Perhaps it wasn't necessary to have as many children anymore (social security)? Regardless what the reason is, birthrates have declined in developed countries. This allows us to plot a peak for the human population and decline afterwards. We don't need to worry about overpopulation anymore.

Will this pattern hold though? What if it turns out that when a society hits a GDP per capita of $500k of today's money that the birthrates start increasing again? 3% growth of GDP per capita plotted over 80 years would put US GDP per capita at $668k. What's the chance that there is no societal break point in the future that reverses the birthrate decline? Quite a few countries seem to be actively working on trying to find something like that.

[X6S1x6Okd1st]

Female empowerment is what is listed in the paper and what is generally accepted.

I've typically heard two drivers:

1) children turned from an economic boon/necessity to a sink. They can start helping with farm work pretty early, not quite so much when the industry work, they have to be somewhat older and can't tag along when the parents are working.

2) women could spend their time working and earning money. They could start to support themselves.

We've been able to accelerate this trend by offering access to contraception and decreasing infant mortality.

[Zenbit_UX]

Not just empowerment but education. The higher educated a woman is the more TFR goes down.

[pps43]

> we were taught about the idea of overpopulation in school

That's a problem with school education. They give the wrong models. Exponential growth is impossible in nature because at some point it runs out of steam and fizzles out. Logistic curve or probit is a much better abstraction.

[neckardt]

I think the assumption was that humans would continue growing exponentially until they reach the carrying capacity where they're all fighting for the same resources. Then the population stops increasing because there's not enough food/water/shelter to go around.

What actually happened is people in rich countries have plenty of food/water/shelter to continue reproducing... if they wanted to. The thing the models didn't account for is that people would choose to have fewer children based on standard of living.

To me it seems this had nothing to do with the standard limits of nature, but based on individuals' choices. Given those models' assumptions, I think they were valid. I would have made the same assumption based on past data as well.

[stkdump]

I recently heard about a survey where people on average said that they do want to have 2.something (lets say 2.4, but I don't remember the exact number) kids. I guess it is easier to prevent overshooting, but sometimes life circumstances prevent them from having as many as they wanted. That can be as simple reasons as not finding the right partner, etc. What you see less often though, is people that want to have 4 or 5 kids, which I think is stigmatized, but it could even out those that don't have kids.

[jolmg]

> What you see less often though, is people that want to have 4 or 5 kids, which I think is stigmatized

That might vary by culture, but I can't think of a time when I've seen it be stigmatized. I imagine that current generations chose to have less than 4 kids for economic and quality of life reasons, not because they see having many kids as somehow wrong.

[pps43]

That's not a new idea. Walter Greiling projected back in the 1950s that world population would reach a peak of about nine billion, in the 21st century, and then stop growing [0]

[0] https://en.wikipedia.org/wiki/Projections_of_population_grow...