The Demographic Future of Humanity: Facts and Consequences [pdf]

19 akyuu 16 8/11/2025, 5:03:33 PM sas.upenn.edu ↗

Comments (16)

Arainach · 18m ago
The complaining about fertility rates, mostly done by the chunk of the population hoarding more and more of the wealth, will continue until people's ability to afford rent and children improves.
rayiner · 13m ago
Rent is the bigger issue than affordability per se. My wife pointed out the other day that we had our second and third kids shortly after we stopped living in apartments and bought a house. We didn't plan to have a significant age gap between our first (who we had in law school) and our other kids, and we earned a lot of money the whole time, it just happened that way. She's convinced that having the extra space subconsciously encouraged us to have more kids.
vonneumannstan · 11m ago
This totally ignores the fact that the decline in fertility is measurable across the globe in the poorest and wealthiest nations in the world. It's clearly not a simple matter of affordability...
cyberax · 5m ago
The drop in fertility rate is directly liked to migration into dense cities. They are just not a good place to have children.

The US resisted the fertility drop for much longer, because of higher suburban population.

vixen99 · 7m ago
'hoarding more and more of the wealth'. Sounds very much like you believe in the pie fallacy. A zero sum game? Maybe that's not what you meant though.
api · 15m ago
The thing that collapses in a negative population growth environment is passive earnings from interest and asset appreciation, retirement, and to some extent social welfare states. The whole idea of things like social security is predicated on a growing population paying for the elderly. It's also very, very bearish for things like real estate long term. We are probably still in a real estate bubble.

I suppose I've never expected to ever be able to retire unless I get truly wealthy. It's not something I've ever included in my life plan because I've kinda seen the writing on the wall about this since I was in my twenties.

I don't think this crash in fertility is that unexpected, and it's not even all bad. It'll help us weather things like climate change and natural resource depletion.

toomuchtodo · 13m ago
Social security is solvent for at least the next 75 years if the US removes the payroll cap on contributions from wage income. We choose not to. The economic resources exist for these social programs, it will just diminish profits (the horror /s). It's a policy choice.

Every year total fertility rate remains lower than replacement rate further locks in the fertility curve, but there is no political will or desire to implement the fixes required. So, we keep kicking the can until we cannot anymore. It's unfortunate. Demographic destiny comes regardless.

https://usafacts.org/articles/how-much-does-the-us-spend-on-...

https://www.pgpf.org/article/social-security-reform-options-...

jmclnx · 8m ago
This is all well and good, but population dropping will only impact our civilization a little. I think this is an issue only because the "very rich" may actually see their standard of living fall. For the poor, it will have no real impact.

Plus it is probably a good thing population will start dropping.

The much larger worry should be Climate Change, a dropping population can only help Climate Change in the long run. But right now, due to how we all live, we are heading into a whole lot of hurt due to Climate Change. Far more "hurt" than the population falling.

Also, worried about population dropping ? Wait to see how fast it drops when Countries start massive wars due to dwindling resources.

EDIT: want an example of the Impact of population dripping ? Look at Europe during the Plague in the 1300s(?). What happened was the rich had a hard time finding labor, so they had to start paying people a lot more for their work. To me, that is the big fear, the rich may have to start paying more.

api · 27m ago
Paul Ehrlich was almost exactly wrong about everything, but he continues to frame the discourse to a ridiculous degree. I'm not sure what the magic pixie dust is that allows people to be this wrong and still have credibility.
profstasiak · 23m ago
how is Paul Ehrlich linked to the original post?

what is he wrong about?

UncleMeat · 14m ago
Paul Ehrlich was the most visible figure in the midcentury fear of overpopulation. He claimed that by now we'd have seen starvation so profound around the world (100,000,000s dead of starvation) that large portions of the third world would collapse completely and that the only mechanism to prevent this starvation was extreme population control measures placed by the west on the rest of the world (including things like partitioning India and just letting some regions starve completely to death with no aid). He believed that the sustainable population for the planet was one billion.

He was completely wrong. I think it is a great example to use in these modern discussions. Just 50 years ago we were seeing highly influential people say "we are going to breed ourselves to death and the only solution is extreme curtailing of rights." Today, we are starting to see highly influential people say "we are going to not-breed ourselves to death and the only solution is extreme curtailing of rights."

api · 12m ago
Unfortunately a lot of people are now saying we need extreme curtailing of rights -- largely womens' rights -- because of underpopulation. The answer to every panic is always curtailing of rights. Scary thing may happen therefore we need big alpha ape to fix it for us by bashing people on head with big rock. Grunt, grunt.
UncleMeat · 7m ago
Right this is what I am saying. And I think that we should be outrageously skeptical of such people and oppose them with fervor. In the 70s people were saying that we needed to commit brutal oppression against a large portion of the world based on geography in order to prevent future catastrophe. These people were wrong in every possible dimension and has we listened to them we would have committed a world-historic evil.

Similarly, we are starting to see people say that we need to commit brutal oppression against a large portion of the world (this time based on gender) in order to prevent future catastrophe. I suspect that these people will be wrong in every possible dimension and that if we listen to them that we will be committing a world-historic evil.

retrocog · 25m ago
This trend doesn't bode well for the long term survival of the social welfare state.
rwyinuse · 20m ago
That depends very much on how technology progresses during coming decades. If we get something like AGI, then having less working age people may be a good thing, because there will be much, much less demand for white collar workers at least.

In the mid 2000's when I was a kid, at school I was taught that there would be a HUGE labour shortage once certain large generations retire, as younger generations are much smaller. Guess what, they retired a decade ago, and yet my country has the second highest unemployment rate in EU, with a very weak job market for fresh graduates in particular. Increased efficiency & automation ate all those jobs, nobody was hired to replace many of the boomers who retired. I doubt the future will be any different.

toomuchtodo · 23m ago
Social welfare state will still exist, it'll just be more costly as drag than it is today (in the US, ~$1.1T/year of uncompensated caregiving occurs, for example). Capitalism is more the challenge, it's built on squeezing the aggregate working age population for profits, and that cohort is in terminal decline over the long term. Between global sovereign debt load [1] and the demand for future profits (slides 31-33 of this PDF), there will be sadness as the future has less and less humans to saddle these economic burdens on. Such are the breaks when you predicate a socioeconomic system on never ending growth, and growth is over because humans globally (for various complex and interwoven issues) are choosing to have less children or no children.

[1] https://unctad.org/publication/world-of-debt ("Global public debt surpasses $100 trillion in 2024.")