
Two centuries of rapid global population growth will come to an end - sohkamyung
https://ourworldindata.org/world-population-growth-past-future
======
dzdt
A major point the article is missing is that after population peak comes
population decline. The pattern of "demographic transition" is that as
lifespans extend, infant mortality declines, and lifestyles change the
birthrate drops. But it doesn't drop just to replacement rate, it drops much
below replacement rate.

Most developed countries are in this state now where their population would be
declining but for immigration.

When today's fast-growing countries reach the same point in their demographic
transitions, the whole world's population will enter decline.

This could happen even earlier than around 2100 when the UN estimates; other
demographers are forecasting a date more like 2065. [1]

What will the economics be of a world in population decline? How will culture
and policies change to eventually stabilise the decline? Lots of questions...

[1] Lutz et al 2018 :
[https://ec.europa.eu/jrc/sites/jrcsh/files/lutz_et_al_2018_d...](https://ec.europa.eu/jrc/sites/jrcsh/files/lutz_et_al_2018_demographic_and_human_capital.pdf)

~~~
nerdponx
_A major point the article is missing is that after population peak comes
population decline. The pattern of "demographic transition" is that as
lifespans extend, infant mortality declines, and lifestyles change the
birthrate drops. But it doesn't drop just to replacement rate, it drops much
below replacement rate._

Great. Better to have it happen through declining birth rates than through
natural disaster, pandemic, starvation, etc.

~~~
raducu
Those are not exclusive, you know that, right?

On the contrary, a shrinking population is much more likely not to be able to
manage those issues.

~~~
hinkley
Or an aging population.

When I was in college some of the profs offered extra credit if you wanted to
go bag sand for major flooding about an hour away (a nice way to let people go
home and help their family and friends).

Strong backs and enthusiasm are good for augmenting the experts in a disaster
recovery situation.

------
comboy
Related to that, I highly recommend Factfulness[1]. You can try to answer 13
a/b/c questions here[2]. Most educated people score lower than if they would
have just chosen answers randomly. It's really hard to discuss population and
poverty if most people worldview is so skewed.

Btw, I've been wondering how population stabilization (it pretty much already
stabilized in the US and EU) will influence real estate. Historically real
estate have been a remarkably good investment. But historically population
kept growing pretty fast. I'd love to hear some thoughts or recommended
reading on that topic.

1\.
[https://www.goodreads.com/book/show/34890015-factfulness](https://www.goodreads.com/book/show/34890015-factfulness)

2\.
[http://forms.gapminder.org/s3/test-2018](http://forms.gapminder.org/s3/test-2018)

~~~
SomeOldThrow
There are massive issues with the calculation of poverty designed to give the
illusion of progress under globalized production chains. In reality, the
metric is completely disconnected from what people identify as poverty. The
entire premise is flawed. See: Steve Pinker for an example of this technique
in use.

~~~
beat
Have you read _Factfulness_? He is very explicit about what he means with his
different levels of income and changes in poverty - using examples of physical
situation, not mere money. (Like at what point in the cycle do you own shoes?
Can afford a bicycle? Have running water? What do these things mean for your
income potential in the future, or that of your children?) Dr Rosling worked
for much of his life as a health care provider in the poorest places on Earth,
and was intimately familiar with what real poverty looks like, in all its
details.

~~~
SomeOldThrow
Yes, and I think it’s a boneheaded and disingenuous argument. Much, if not
most, of the world is blatantly in poverty and cannot afford a quality
standard of living. Comparing it to a world with equitable wealth distribution
would be much better. This is how the western world justifies open
exploitation.

~~~
beat
That's the bias of privilege talking.

Going from $2/day to $8/day may not seem like much to you, but to someone at
that level, their income has quadrupled. They might have access to a bicycle
to get to a paying job now. Shoes. Clean water. School for their children, so
the next generation has more opportunity. Go from $8 to $32 (using Rosling's
quadruplings here), and you now have a car, potable hot and cold water from a
tap, even the possibility of college for your kids. It's still "poverty" to
us, but not all poverty is the same. Understanding this is a shift in
perspective, and requires putting down our wealthy, western privilege for a
moment.

Keep in mind, too, that a world of no health care, no clean water, no
literacy, etc - the extreme poverty of the poorest nations - was the situation
in much of Europe during the 19th century. It took Europe a long time to get
to where it is today, and much of the progress happened in the post WWII, post
colonial era. "Open exploitation" is not what you think it is, not anymore.

As I've pointed out elsewhere, much of the world has seen income increases
from 20x-100x per capita in the past 50 years. That's the poor, "exploited"
countries.

 _Economic change takes time_. Generations. The fact that we wiped out two
thirds of the world's extreme poverty isn't "boneheaded", it's incredible. But
it will take several more generations to get the rest of the world up to the
standards of our privilege.

~~~
SomeOldThrow
As I said, marginal improvements are used to justify ruthless exploitation.

~~~
beat
I have a hard time thinking of the 20x improvement in Egypt or the 100x
improvement in China (or similar gains elsewhere) as "marginal improvements".
We're talking orders of magnitude improvements in standard of living over the
course of a couple of generations.

I don't know what you're expecting. Someone snaps their fingers and everything
is magically "fair"?

------
ElonsMosque
Except in Africa. The population is expected to double until 2050 and
potentially double again by 2100.[1]

[1] [https://uk.reuters.com/article/uk-health-global-
gates/africa...](https://uk.reuters.com/article/uk-health-global-
gates/africas-rapid-population-growth-puts-poverty-progress-at-risk-says-
gates-idUKKCN1LY0GQ)

~~~
igravious
That's okay, because the population density of Africa is very low (it's
comparable to that of the Americas, much less than Europe/Asia)[1], it's
currently only 15% of the world's population[2], and Africa is an enormous
continent[3] the fact of which the Mercator projection distorts[4].

[1][2] [https://www.geolounge.com/continents-population-
density/](https://www.geolounge.com/continents-population-density/)

[3] [https://io9.gizmodo.com/africas-true-size-will-blow-you-
away...](https://io9.gizmodo.com/africas-true-size-will-blow-you-
away-1441076531)

[4] [http://www.petersmap.com/](http://www.petersmap.com/)

~~~
danmaz74
It's an enormous continent, but a lot of it is covered by deserts and other
inhospitable environments

------
jacquesm
Such long term predictions have relatively little value due to the sensitivity
to the initial inputs. Any small deviation from reality will result in a huge
deviation in the longer term and 80 years is much too long to predict with any
accuracy.

Typically the only useful info you can get out of such long term studies is
the sign of the change and the order of magnitude.

~~~
Certhas
This is absolutely incorrect, and you have no idea what you are talking about.
There is no sensitive chaotic model behind this, it's completely
straightforward dynamics.

The fertility rate is about 2 kids per woman now. But the generation of 20
year olds is much larger than the generation of 40 year olds. So even though
the generation of 0 year olds is the same size as that of 20 year olds, in 20
years time we will have replaced a small 40 year old generation by a large 20
year old generation.

There are only two factors here: Fertility rate per woman, and death rate.
This prediction is not terribly sensitive to either, and both are easy to
measure accurately and on quite stable long term trajectories:

[https://ourworldindata.org/fertility-
rate](https://ourworldindata.org/fertility-rate)

~~~
Retric
Look at the error bars for the U.N. estimates. 95% chance between 9 billion
and 13 billion 80 years from now is not exactly a narrow band.
[https://population.un.org/wpp/Graphs/Probabilistic/POP/TOT/9...](https://population.un.org/wpp/Graphs/Probabilistic/POP/TOT/900)

One extreme unknown is global life expectancy. New diseases, or new cures for
existing diseases can make a huge difference. Add in wars, economic growth,
and a host of other factors making long term estimates are hard. Just consider
how accurate past population estimates have been.

~~~
Certhas
P.S.:

> Just consider how accurate past population estimates have been.

Uh, fairly accurate as far as I know? There were always bad extrapolations and
naive papers and articles, but the state of the art predictions didn't do
badly, especially after data quality improved.

Also, again, the major driver for the predicted dynamics is the collapse in
fertility rate that has already happened, and no longer needs to be predicted.
This is a vastly simpler question now than it was in the 70s.

Look at this graph:

[https://population.un.org/wpp/Graphs/Probabilistic/FERT/TOT/...](https://population.un.org/wpp/Graphs/Probabilistic/FERT/TOT/935)

Of course in 1970 it's almost impossible to predict how quickly Asia will
experience the cultural, economic and technological changes that reduced the
fertility in Europe dramatically over the previous century. Today the
transition towards small family sizes has happened. We still have drift (as we
see in Europe too) but the important major driver of going from roughly 6
children per woman to 2 children per woman has happened. So the biggest
uncertainty factor in old forecasts is gone.

~~~
Retric
The 10 year forecast for U.N. population made in 1990 was off by 3.3%.

They have gotten fairly close with long term estimates a few times, but a poor
track record for predicting deviations from existing trends.

------
raducu
It could be that we are approaching a great filter: "when an intelligent
species has the freedom to decouple the great incentive for reproduction
(sexual pleasure) from the actual reproduction, it turns out individuals
choose not to reproduce, which leads to the collapse of the whole
civilization"

~~~
benj111
From what I understand people are having less sex period.

I guess its some combination of women's lib (women more likely to say no to
sex, relationships and children, wanting careers), people working more (side
hustles are now a thing), and there now being more things to do (you can now
socialise on the internet without actually meeting anyone).

~~~
adrianN
Sperm counts in men are on decline as well. There might be some environmental
factor.

------
Symmetry
The fact that fertility is heritable makes an end to population growth
unlikely.

[1][https://www.sciencedirect.com/science/article/pii/S109051381...](https://www.sciencedirect.com/science/article/pii/S1090513817302799)

------
Nursie
That is interesting.

But I wonder how the model would be affected by, say, the mass availability of
a significant longevity increase, brought about by some sort of medical
breakthrough?

~~~
IAmEveryone
Since people would presumably not use that extra time to have more children
(they aren’t time-limited now), the result would just be a linear increase in
population. The important part here is the change from the exponential models
of Malthus etc.

~~~
jacquesm
> they aren’t time-limited now

They mostly are actually. Barring the occasional exception there is a definite
20-40 or so age band where most females that have children will have them.
This is in part because of society and custom and in part for very valid
medical reasons, the chances of children having birth defects go up quite fast
past the age of 35.

~~~
tntn
I think that 'IAmEveryone likely means that people aren't lifetime-limited.
Most people aren't reproducing after 40, but expected lifespan is much more
than that so even if it doubled there wouldn't be more children.

------
jlawson
These predictions are laughable because they ignore the fact that fertility,
like everything else, is heritable.

The people who aren't reproducing will die out. The people who are reproducing
will do so, and their kids will keep reproducing too. These are separate sub-
groups of the population.

As a very simple example, the Amish population doubles roughly every 20 years
because of their high and early birth rates. It's not hard to calculate that
there will be billions of them within a few centuries because of the power of
exponential growth.

Any analysis which doesn't separate sub-groups by fertility, or handle the
heritability of fertility, is meaningless.

All we're in now is a temporary state caused by rapid introduction of birth
control and porn and other such technologies which suppress fertility. No
different from hitting a bacterial colony with a drug that stops 90% of them
from reproducing. It reverses growth for a few generations, but the logic of
evolution and exponential growth always wins in the end and the population
hits its carrying capacity once again. Which for humanity with modern tech, is
going to be a very, very ugly situation.

~~~
jessaustin
It's far more likely that the Amish will have disappeared altogether in "a few
centuries" than that they will number in the "billions". There is no Amish
gene.

~~~
jlawson
You can just flatly assert that, but it'd be more interesting if you supported
your assertion with some kind of argument. What exactly do you think is going
to dissolve the Amish that didn't do so already? Do you not think fertility is
heritable, and if not, how not?

Also, who said anything about genes? Sub-groups can be separated by culture,
religion, genetics, or any combination of the above. Amish are separated by
all 3.

Religiosity is also linked to genetics; this is scientifically established
(though not totally proven yet).

~~~
iamnothere
Not the person you're replying to, but I'll give a hypothetical argument. The
Amish have an extremely successful culture right now because their society
positions them advantageously versus the predominant culture. Their practices
are excellent for building strong communities and providing efficient,
effective mutual aid in a form that is lacking in society at large; and unlike
what most people think of the Amish, they do adopt some modern technology, but
only that which strengthens the community.

As the Amish community grows, they will face the same challenges faced by all
growing, successful "challenger" cultures: envy and resentment, followed by
active undermining of their culture and attempts at assimilation through
popular media, fashion, and a hostile legislative environment. (This presents
itself as a sort of "embrace, extend, extinguish" effect, with the end product
being ethnic restaurants and kitsch once the culture has been fully digested.)

The Amish may be able to adapt to face this challenge, but what often happens
is that the process of adaptation ruins the good and unique things about the
culture, and the assimilation happens anyway. Cultures that resist this effect
stay small by necessity.

An example of a culture recently reaching this "breakout" point where pushback
is encountered is the Hasidic community in New York. A good example of a
culture that is left alone due to its small size is the Sikh-American
community. An example of a fully digested culture is the Italian-American
community, which no longer exists as a separate identity.

~~~
jlawson
Well I'm not saying the Amish are "successful" in any sense of morality or
human flourishing; I'm making no claim on that. I'm just saying they multiply
fast. Not a judgment, just an observation.

I agree the pathway would definitely change. You'd see pushback. It's not like
the Amish will be 300 million in their exact current format.

So let's say that does happen and the Amish start getting targeted for
"embrace, extend, extinguish", or some variation of semi-forced immigration
and assimilation.

Amish aren't homogenous. Some of them would be taken by this, assimilate, and
drop birth rates. Some would not. Whatever characteristics made that last part
not assimilate would then get replicated into a larger and larger population
share. And the process continues.

We may see several phases of this, but at the conclusion of the process, the
evolutionary logic leads to a certain result: A population who are absolutely,
totally immune to any influence that would assimilate them into a negative-
birthrate culture. And that population will rapidly expand until it hits
physical limits.

The reason I think this is inevitable is because evolution is relentlessly
adaptable, while the countermeasures are fairly static. It's like a new
antibiotic. Even if it works really well, the bacteria's evolutionary process
will just keep trying and trying until it finds a new replication pathway. The
replicators can adapt forever while the force that is stopping them cannot.

~~~
iamnothere
A thoughtful response, and I think you are right in that not every Amish sub-
community would be assimilated. This is already happening; there was a chapter
in Kevin Kelly's "What Technology Wants" that describes the differing
perspectives within the different Amish communities on things such as
technology. There are some Amish communities that resist almost all modern
tech; these communities are probably more likely to stay small over time (hard
to attract and keep members), but I imagine they are also less likely to be
absorbed into modern society than the rest of the Amish population. To me, it
appears that some sub-subcultures manage to maintain their identities by
putting up huge barriers to entry; the more costly they are (in terms of
personal sacrifice), the more likely that the culture will maintain its
identity, up to a certain point.

Robin Hanson has described this a fair amount as well. Some cultures have a
"price of admission" that can't be easily faked (I forget his term for this)
in order to protect their group resources against disloyal outsiders who may
take advantage of the group. This explains a lot of the bizarre,
contradictory, and otherwise illogical practices that you see in these insular
cultures.

------
peteradio
>> This new equilibrium is different from the one in the past when it was the
very high mortality that kept population growth in check. In the new balance
it will be low fertility keeps population changes small.

What is the reason for low fertility prediction?

~~~
Creationer
Excessive taxes and expensive housing. In much of Europe it is simply
impossible to buy a house on a single income, if you obey 100% of tax laws.
These taxes are used to pay for the elderly, their welfare (pensions) and
healthcare.

If you are in the US you may not appreciate how heavy the tax burden is in
Europe. It varies by country but its normally something like: 30% payroll tax
paid by employer. 30% income tax paid by you. 20% sales tax paid by you. Then,
very expensive housing due to the high population densities and limited room
to expand.

Additionally in Europe, many parents want their children to be educated in
English, however the language of instruction is usually the local language.
This is partly why the migrant stream into the Anglosphere is so high. The
alternative are private international schools, which are hideously expensive.

~~~
adrianN
Much of Europa has very cheap houses because populations are declining. It's
just in large cities that real estate is becoming expensive.

~~~
Creationer
And just like the US the jobs, education and culture are in the cities.

Housing in a second-tier Polish city is more expensive than Chicago!

[https://www.otodom.pl/oferta/klimatyczny-apartament-
balkon-w...](https://www.otodom.pl/oferta/klimatyczny-apartament-balkon-winda-
st-rynek-ID3Xt1m.html)

[https://www.zillow.com/homedetails/5345-S-Ellis-
Ave-H2-Chica...](https://www.zillow.com/homedetails/5345-S-Ellis-
Ave-H2-Chicago-IL-60615/2097963695_zpid/)

------
mensetmanusman
The population decline projected follows a similar % drop versus time as the
Black Plague.

Fascinating.

------
NotPaidToPost
This is one of the major cause of the destruction of the environment we're
seeing globally.

All forecasts predict another 60% (!!) increase in global population before it
stabilises.

Forget about banning plastic straws or flying less (which are feel-good
measures more than anything else) with such numbers... We need to take
dramatic and effective steps.

There are 80 years left until the end of the century. This increase is far
from being inevitable! But, again, we prefer to ignore these key issues and
focus on marginal, feel-good measures instead.

~~~
roca
Perhaps you didn't read the article, because its main point is that the
official UN forecast is for world population to essentially flatten out at
10.9B around 2100, which is 40% more than today, not 60%.

~~~
NotPaidToPost
11B from 7B is a 60% increase... But that's the usual sterile nitpicking. Do
you want to argue about decimal points or address the actual point?

The important point is that this is a large increase when we already cannot
manage now.

~~~
bryanlarsen
"we already cannot manage now."

Correction: we don't want to manage now. The world has far more than enough
wealth and resources to hold climate change to 2 degrees and to stop clear
cutting rain forests.

~~~
ForHackernews
Point of order: 2 degrees of climate change will still be disastrous
[https://www.rifters.com/crawl/?p=8433](https://www.rifters.com/crawl/?p=8433)

------
car12
News items like these are then used as fodder for higher immigration limits so
that the liberal parties keep getting elected further, even as they enjoy less
and less support from their already existing citizens.

~~~
wtdata
Actually, almost all of the democratic acts in the West lately (don't mistake
the echo chambers which one of us is submitted to in social networks for the
will of the majority), show a clear support for parties that - amongst other
things - want higher immigration limits.

EU parliament elections, EU local elections, USA presidentials, Brazil, and
the list goes on.

~~~
car12
I should clarify, I meant: higher numerical intake limits for immigrants to
developed countries.

Basically, most of the liberal parties have found this "hack" to win
elections. Where they wouldn't be able to win elections normally, they simply
keep importing more and more people, and these immigrants reliably vote for
these parties. Eventually, these places end up becoming one party states.
Consider the case of California as an example.

It's quite an indictment of the democratic processes.

~~~
wtdata
But, liberal parties have been loosing an awfull lot of elections lately,
clearly this is no "hack" to win elections because it is not working as you
state.

It's their ideology and it is up to the democratic process to judge it
(favorably or unfavorably). And - although personally I favor controlled
immigration only - it is perfectly healthy for a democracy to have parties
that defend and present other perspectives.

~~~
car12
> clearly this is no "hack" to win elections because it is not working as you
> state.

Like I just said, it's working extremely reliably. Look at California, the
opposition is decimated there not by the merit of liberal parties work or
argument but by the sheer number of immigrant votes. Granted there is a delay
factor such that new immigrants can't vote but the mechanism of immigrants
voting for liberal party is still at work.

This is just for state level, I predict something similar happening at Federal
level elections in a 1-2 election cycle period. Trump election was an
exception IMO.

------
yters
There is always the doomsday argument: we should expect a significant
population decline in the near future in order to justify the statistical
typicality of our present day existence.

------
igravious
This data should mandatory in all school curricula throughout the world. One
of the greatest impediments to understanding the social reality of the world
around us is the general population's ignorance of this data.

We need people to (a) understand that the world's population is increasing but
that the rate of increase will inexorably slow and that (b) this means that
the population will plateau. We then need people to ask themselves can the
Earth support that level of population of 11 billion. The answer is an
incontrovertible "yes". Anybody who claims the Earth cannot support 11 billion
people is factually incorrect. Is it going to cause environmental stress? Yes.
Will it cause environmental collapse? No.

People also fail to understand this other simple fact. Even though there will
be more mouths to feed, there will be _more hands to make the food_. And given
economies of scale, it'll arguably be _easier_ to feed 11 billion than 7
billion.

~~~
makerofspoons
I would love to see a citation for 11 billion people not causing an
environmental collapse.

At our current population 40% of insects could be extinct in the coming
decades, and over the last 50 years 60% of animal populations have been wiped
out: [https://www.cnn.com/2019/02/22/health/food-biodiversity-
repo...](https://www.cnn.com/2019/02/22/health/food-biodiversity-report-
intl/index.html)

~~~
igravious
Species extinction and animal population decline is not the same thing as
environmental collapse.

edit: To clarify, people say that we have exceeded the carrying capacity of
the Earth or that we'll exceed it as the population mushrooms. This data
proves the population won't mushroom, and I assert that 11 billion is well
within the carrying capacity of the Earth. Do I have any proof? No. But
neither do the doomsayers who claim otherwise. That's the specific narrative
I'm trying to push back against.

~~~
notfromhere
what do you think _is_ the environment? we can't survive without biodiversity

~~~
igravious
We both know what the environment is.

What you meant to say is that we can't survive below some threshold of
biodiversity. Nobody's talking about zero biodiversity. What do you think that
threshold is? I think we can survive (and the environment will be okay with)
less biodiversity. How much less that turns out to be I guess we're going to
find out.

