I think all of these analyses contain a critical flaw in that they ignore the effect of evolution. Any characteristic that increases reproduction rates that is passed down to the next generation, whether that characteristic is cultural, location-specific, or genetic, will eventually become the majority. (And yes, cultural beliefs and location can be "passed down" to some degree.) This will result in eventual birth increases as pro-fertility adaptations build up. You can't assume that the system is static and that trends will continue when the math of evolution inherently promotes a pro-reproduction bias.
So you're saying this whole world is a game where if a species is not intelligent enough to know when to stop reproducing in order to save the environment, it's an inevitable game over? :)
I do not believe the world will hit peak child, unless there is a catastrophe.
Looking at overall birth rates might make it seem that way. But logically, in order to hit peak child, every subgroup will also have to hit peak child. Will every single country hit peak child? Will every religious group hit peak child? All it takes is one of those groups to keep expanding, and the world will not hit peak child. There are so many subgroups with drastically different birth rates and retention rates, I don't believe we will hit peak child. There will just be a transition period as the world starts to contain fewer Italians and more Mormons.
> In order to hit peak child, every subgroup will also have to hit peak child.
This is an interesting argument; thanks for sharing it. I didn't understand it right away and my intuition was that you must be incorrect. But after playing with some actual numbers I've come to understand. In an attempt to restate your claim in a way that's more intuitive to me:
If a group is reproducing above the replacement ratio, then they haven't hit peak child yet. So if only one subgroup remains that hasn't hit peak child, then that subgroup is also the only one that's growing (all others are shrinking). Assuming that trend continues (read: assuming subgroups have birth rates that reflect their culture, and that culture will be preserved in the next generation), this subgroup will grow without bound.
The pressure-release on a system like this (one which the article you linked points out in its conclusion) is that birthrate within a subgroup isn't fixed. The birthrate among the Amish appears to be declining slightly, perhaps influenced by economic forces in the US. In your example, while it's true that _tommorow_ there will be more Mormons and fewer Italians than today, that doesn't guarantee that eventually the world will be populated entirely by Mormons, because the birthrate in that subgroup isn't wholly 'inherited' (in the cultural sense) -- it may change in ways that we can't forecast today.
Not really, because subgroup membership is flexible: people can enter and leave a subgroup. But even ignoring that objection, calculating that the Amish will eventually outnumber everyone else is a crazy bad extrapolation, whereas predictions of world population are based on much more modest and justified extrapolations.
If you took some old population data you could perhaps extrapolate that Shakers were destined to increase exponentially, but what happened to them? I'd say that the destiny of a single religious group is typically a short-term and local phenomenon that doesn't much affect the long-term development of world population.
I don’t claim that the Amish will eventually outnumber everyone else. I merely claim that for the global population to hit peak child, every subgroup has to hit peak child. That is a very mathematically sound statement. To me it seems intuitively unlikely that every subgroup will exhibit the same trend. What I expect in practice is not that the Amish will outnumber everyone else, but that over time many different subgroups that are expanding their population will continue growing, and thus world population will continue to grow.
Claim: In order for the overall population to hit a maximum number of children, every subgroup within it must also hit a maximum number of children.
Proof: Assume the opposite, that there is a subgroup S that never hits a maximum amount of children, but the overall population has a maximum amount of children X. Since S does not hit a maximum amount of children, S at some point has more than X children. This contradicts the initial assumption. QED
Oh, that's boring. It's almost as boring as saying that the number of any countable physical thing must reach a maximum because it is bounded by the mass of the universe divided by the mass of an electron, or something equally tedious. I don't think we're gaining any insight here.
World population decreases because people are dying, and increases because people are being born. It's enough to decrease the total population to have the global reproduction become lower than global mortality.
By the same token, if a certain group keeps reproducing at a high pace, but the majority of the world keeps having fewer and fewer children, the overall number of children will decrease, so the curve will be past the peak.
No, my statement is very simple and mathematically correct. In order for the global population to hit peak child, every subgroup must also hit peak child. You cannot have a finite set contain an infinite set. You may think that every subgroup will hit peak child and thus the global population will hit peak child - that is logically consistent. But you cannot believe that some subgroups will expand indefinitely, but the global population will peak.
Your assertion seems true only if
subgroups can maintain a positive growth rate indefinitely, which is theoretically possible but hardly proven, particularly as history show that subgroups that grow too much splinter, and the splinters do not all maintain the parents growth rate. Most splinters dwindle, so a simple exponential growth does not apply for long. (On a global scale.)
> But logically, in order to hit peak child, every subgroup will also have to hit peak child. All it takes is one of those groups to keep expanding, and the world will not hit peak child
No, it just has to make less children than it did eighteen years before.
Your condition of "make less children than it did eighteen years before" does not cause a permanent decline. That one subgroup keeps growing. Eventually, the population of that subgroup exceeds today's world population, and your condition is no longer met.
I must have misread you, because I thought you were writing "All it takes is one of those groups to keep having children".
Well yeah, obviously as long as the population keeps growing [1] (and for that it is sufficient that a subgroup does indeed), there can not be a peak child.
I was assuming that the article posited the existence of a population peak in the future, and was speculating about how many years would it be preceded by a child peak.
1. or rather, renew generations, since the population can grow without renewing generations.
Weird that religion isn't mentioned -- possibly too contentious -- but I thought the correlation within societies of high religiosity and reduced education opportunities for (or just general resistantance to the empowerment of) women was fairly well understood.
Tracking changes in religious beliefs in different demographics can give us some good predictive insight.
In previous studies of this I thought they had shown that when correcting for women’s education levels & wealth religion largely didn’t play much part.
There are many variables to this. I believe politics/economics, culture and religion do have their fair share of weight. For example communist countries, which have been ideologically opposite to religion, provided higher education to women, compulsory even. On the other hand I've read that in Nazi Germany women were also given quite a lot of rights and work responsibilities.
I just yesterday searched github to investigate female employers of the likes of google and microsoft. A significant amount of them were Chinese or Indian. It's really about how much resources a country invests in free (university level) education.
Most Christian countries aren't dominated by Christian extremists. Look to cults or isolated sects, though, and you'll find the hallmarks of true patriarchal oppression.
Most Muslims in Germany are not particularly extreme and send their daughters to school just like their sons and yet they have a much higher fertility rate that other groups in Germany.
It tells me that female Muslims are about as well educated as male Muslims in Germany. From what I hear from teachers, they do better in school than their male peers.
I don't disagree that there are some extremist Muslims in Germany, but I don't think that there are enough extremists to explain the large disparity in fertility between Muslims and non-Muslims.
When you say SA has been complaining about Euro Mosques teaching Extreamism, which definition of Extreamism are you referring to?
The formal one or what Saudis find Extreme? If it is the latter, then Saudis’ complaints would be laughable and ironic since their Human Rights’ record isn’t what anyone would laud them for.
I'm not sure religion correlates that well. Countries like Italy are the centre of the catholic faith but have high education and low birth rates, sub saharan Africa is kind of the opposite.
What we have seen in the different projections of future global population is that Africa is the most influential and contentious. What happens in Africa now and in the coming decades will determine what size and structure the global population will have at the end of the century.18
It seems less certain what the future for Africa will look like; there is considerable disagreement between UN and WC-IIASA projections. Even the medium projections vary significantly between the two institutions: The UN projects a population of 4.5 billion while WC-IIASA projects a population of only 2.6 billion. This difference of 2 billion is just as large as the difference between the projection for the global population by the UN (11.2 billion in 2100) and WC-IIASA (8.9 billion in 2100). Whether the world population increases to more than 10 billion will be decided by the speed with which Africa develops – especially how quickly women get access to better education, women's opportunities within the job market, and how rapidly the improvements in child health continue.
It's really quite astounding. If the UN's predictions are accurate, Africa's population will soar to 4.5 billion, with the Sub-Saharan part alone accounting for 4 of that 4.5 billion. Which means tens or even hundreds of millions of migrants flooding Western nations, making the current crisis seem like a drizzle when compared with this storm looming off in the distance.
You would think this would be major news, discussed openly and often by the talking heads on cable news networks and given front page billing by major newspapers. Instead, you hear virtually nothing about it, unlike (for example) Peak Oil.
The population of Asia is at the same level today: between 4 and 4.5 billions, and while there is quite a lot of immigration relatively speaking, you don't see hundred of millions of immigrants. That's partly because the economy has soared at the same time as the population. And the same reasons who are slowing down Africa's population growth (rise of education) should increase its economic growth.
It's difficult to see now of course because Africa is more unstable and fragmented than East Asia. But a lot of countries in Subsaharian Africa are not worse off than China in the 1990s and have a promising gdp growth rate (not as big as China yet, though)
Cheao solar energy would allow for massive desalination.
The problem of most countries that people flee from is not lack of resources, but inadequate government. People flee to countries that are better governed and thus more prosperous.
The thing is we know how to contain pop growth and it does not have to be drastic like China's. India is trying to implement novel kinds of birth control[1] and in addition, we know educating women [and following into the workforce] helps bring down pop growth in a generation.
So we know the solution, whether the world or locals are willing to implement them are another question.
I don't think there is any way the world remains livable with 12 billion aspirational consumers.
Education and access to family planning. Access to economic opportunities that provide a compelling reason to wait to give birth to children until later in life than directly post-pubescence.
If Westerners were serious about staving off a mass of immigrants they'd work to improve the situations where the migrants originate. That would mean a cessation to mercantilism and colonialism and likely a decline in the quality of life but surely that's a small price to pay
Why do people STILL think it's an unsolved problem? The birthrate among the native born in the West and the Far East are almost universally below the replacement rate. Education and urbanization/development do it.
All it takes is one tiny subpopulation with more than 2 kids per woman, and you get exponential growth. Exponential growth conquers all. If you have a computer science background, think back to big-O notation. Having 4 kids per woman (thus 2 per person) is a growth rate that doubles the population every generation.
So, do the Amish exist? Yes they do. That alone ensures that growth will not stop. Even if everybody else decided to not reproduce, we'd be well above the current world population after a few centuries.
In 1950 60% of the world was illiterate, today it's less than 20.
Have a look at how fertility rates can drop when people get richer and governments allow some fertility control. In the Islamic Republic of Iran fertility rates dropped from about 6 per woman in 1980 to below replacement in 2005.
There are only 2 major societal problems in the world (1) how to produce a lot of energy for cheap without damaging the ecosystem (2) how to get people to sustainably value common good at least at par with individual good.
Given (1), a few thousand skyscraper farms are enough to support the food needs of our entire planets population. When I did the calculation, I was surprised how little it actually takes.
For (2), the simplistic pure capitalism and pure communism experiments have clearly failed but there are various "in-between" experiments running (northern Europe, Xi Jiping's China, Singapore etc) which seem to be heading to both individual and societal prosperity.
It's also likely Africa will grow a fair bit economically leading to less migrants and a reduced birthrate. Africa's a big place - you can fit a lot of people in.
...what this means is that Africa may become the center of world affairs in the 22nd century after they become rich and developed.
The West and the East will both be somewhat impoverished (relatively speaking, not in an absolute sense) by aging and shrinking workforces. They'll be desperate for workers from Africa.
THough I agree education will bring down the world population I don't see it happening in Asia or Africa any time soon. One of the major reasons for the change and drop in population growth in the west was not just education but the world wars where large number of male population was either fighting or died and resulted in woman joining the workforce in large numbers. Japan had a similar thing happen after the war. China because of its 1 child policy had a similar effect with more women entering the workforce and being educated.
You might find it interesting to read up on other things by the late Hans Rosling e.g. https://www.google.ch/amp/s/www.bbc.com/news/amp/world-39211... - one of his key arguments is the Wests beliefs about 3rd world population growth are largely outdated and lack awareness of how much progress has been made.
He has a lot of good videos out there but this is the one specifically covering Africa / population predictions and the misconceptions / dated knowledge.
In the poster boy of overpopulation, Bangladesh, the fertility rate dropped from 6.2 children to 2.1 children per mother (https://www.ft.com/content/f60e2ddc-0bbc-11e1-9861-00144feab...). No Asian country today has fertility rate above 2.5 AFAIK (except maybe the Philippines).
- The world has probably not reached 'peak child' yet. However, we are likely very close to a long flat peak; the number of children in the world will not increase much more. We are close to the peak.
- A key insight from projections, under different scenarios, is that the number of children in the long-run will depend on how successful the world will be in providing education – in particular to women – in the short-run. This is because women that are better educated tend to have fewer children. If we are successful in providing accessible education for all in the near-term, there will be fewer children – and therefore less demand for education – in the future.
- In the last part of this post I will discuss how the size of the population will change in different world regions. Crucial will be the African continent: fast development in Africa will slow down population growth, whereas slow development would leave African countries in an extended period of fast population growth. The latter scenario could see the African population growing 5-fold over the 21st century.
I don't think there's any uncertainty that the rate of child birth is peaking and is going to decline and continue declining.
There's really no alternative path I can see. One could put it at urbanized, cosmopolitan women aren't interested in child birth unless there are positive options.
I mean, first people thought China's one-child policy was reducing childbirth but a close look and efforts to dial showed the decisions were fairly well set.
Brazil didn't have to have an education outreach program. Ordinary TV was enough to reduce the reproduction rate.
And a variety of nations are looking at their negative reproduction rates (Japan, Taiwan, Russia, France, China etc) and finding there's no easy reversal. It's more like high reproduction are an exception in society's transitioning out of peasantry but after that, it goes down and doesn't go up again.
Its almost like making and raising kids is a full time job, and in places where you have better alternatives to making no money and hoping the fruits of your labor support you 30 years down the line people would rather have a career.
The day you reverse the reproduction rates in countries where they are negative is the day you recognize parenting as a skill worthy of as much credence as teachers, lawyers, or plumbers.
> The world has probably not reached 'peak child' yet. However, we are likely very close to a long flat peak; the number of children in the world will not increase much more. We are close to the peak.
I find this highly unlikely. There is huge selection pressure in favor of any population that is resistant to whatever is causing the general decrease in fertility.
One example is the Amish. For quite a while, now, their population doubles every 20 years. So far they've managed to maintain their fertility, where other notoriously high fertility populations who are less culturally isolated have not.
In the long term, this can only happen when mortality is very high.
There are lots of things that seem to reduce the rate. We can consider education, birth control, taxes, child support, alimony, custody laws, religion, heathcare costs, daycare costs, education costs... and in the end it doesn't matter one bit.
None of that can possibly matter in the long run because the chance of having more offspring than normal is inheritable. You might point at birth control and ask how that fits in, but your ability and willingness/desire to use it is a mental trait that is at least partially inheritable.
You don't see how a child born to a lower class family of 7 might not be less reproductively fit than. A single child from the the same class?
Think of it this way, given what you know of class dynamics and sexual selection in humans, if your child had the choice of selecting between one in a random assortation, without knowing which was which, which one would be advantaged and why?
Let's work that through. We'll do a few generations, starting with 8 families of each type, with each type on their own separate isolated island to keep things simple. We start with 16 people on each island, half male and half female. Going generation by generation:
First: 56 kids, or 8 kids
Second: 196 kids, or 4 kids
Third: 686 kids, or 2 kids
Fourth: 2401 kids, or 1 kid
Fifth: 8403 kids, or extinction
Now, your idea that a child of a large family of 7 is less reproductively fit isn't going to help the low-reproduction families at all. They go extinct; they are thus clearly unfit. Unless the high reproduction families are losing about 5 of every 7 to early death, their population grows exponentially.
In reality, there are not separate islands. The resource exhaustion caused by the high-rate families will not just affect them. Everybody is effected. Even if the high-rate families are more affected, it isn't likely to stop them and anyway there is no saving the low-rate families from extinction.
