
I estimate human population to peak in 2065 - toonies555
https://docs.google.com/document/d/1gUXWSoAVmkOAyztKfJTfNELnZeBtHZiuLVAWi_zYNds/edit?usp=sharing
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anton_tarasenko
A polite reminder: some people predict population dynamics for living.

For example, the World Bank: [http://data.worldbank.org/data-
catalog/population-projection...](http://data.worldbank.org/data-
catalog/population-projection-tables)

If you look for dinosaurs, the WB also have a 1984 report on topic:
[http://documents.worldbank.org/curated/en/496471468156899142...](http://documents.worldbank.org/curated/en/496471468156899142/World-
development-report-1984) (see p. 186, "Population data supplement")

The UN, IMF, and most national agencies also release their numbers.

In general, world GDP growth — and its correlates, like HDI — is stable enough
to predict population growth. As a country gets richer, fertility falls: women
get careers, jobs require more education for children, people start to rely on
savings, instead of family. The aggregate numbers are smooth and predictable.
At least, for a reasonable time horizon.

But you need to fine-tune the model at the right aggregation level. For
example, the US, EU, Japan have similar GDP levels, but fertility in the US
remains high. Census data helps settle down these issues.

~~~
Balgair
Ok, so for everyone that can barely use that terrible website, the number that
they have in 2050 is 9.71 billion. Someone else can try to figure out how to
download that data and then give an actual estimate as to when the population
will flat-line. Maybe find a way to get it into excel and then apply a log fit
to it, or soemthing. Hell, I ain't gonna mess with that terrible site again.

Edit: Forgot to thank my parent comment for finding the data in the first
place!

~~~
pierrec
It seems their data is based on UN research, who publishes regular population
projections. The latest revision, published in 2015, apparently only goes up
to 2100, at which point they still predict growth. However, if you look at
projected growth as it's presented in this article:

[http://blogs.worldbank.org/futuredevelopment/rapid-
slowdown-...](http://blogs.worldbank.org/futuredevelopment/rapid-slowdown-
population-growth)

You can see that the growth is rushing towards zero and almost crosses it in
2100, giving a maximum sometime around 2115. But I wouldn't really count on
any projection's accuracy that far into the future: what really sticks out is
how the historical growth is extremely jagged, driven by crises and
revolutions, then becomes ridiculously smooth as soon as it turns into a
projection. It just screams out "this is a very rough approximation and
probably wrong".

~~~
Balgair
Ok, I get what the article you linked to is saying, but I think it's really
uninformative. Those graphs are the derivative of the population. What I would
most like to see is the absolute number of people on earth over time and then
into the future. The derivative, though important, is not as useful (to me) as
the absolute number. Hans Rosling has some good TED talks on it, but I think
they are probably out of date by now.

~~~
pierrec
The graph for the actual population projection was basically linked in the
article:

[https://esa.un.org/unpd/wpp/Graphs/Probabilistic/POP/TOT/](https://esa.un.org/unpd/wpp/Graphs/Probabilistic/POP/TOT/)

(you have to select "WORLD" in the drop-down)

------
richardwhiuk
There's no testable prediction in this model.

He also just assumes some naive correlations based on some graphs, without
doing any rudimentary statistics (e.g. chi squared to check if the
correlations are even notable), and then plugs the numbers in and see's what
he comes out with.

Instead, he should base his model on data from say 2000, and then predict the
population in 2015, and then if that's correct, he might be able to say
something about 2065 with any degree of certainty.

That he disagrees with other predictions suggests his model is wrong, but it's
difficult to say how.

~~~
fleitz
Yup, reverse malthusianism.

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notahacker
The description of this suggests the analysis is a _lot_ less plausible than
the actual figure:

\- Birthrates are assumed to fall linearly all the way to zero, despite an
abundance of reasons why that's obviously not likely to be the case

\- If I'm reading it correctly, countries' birth rate declines are estimated
as a discrete property of arbitrary HDI labels rather than a function of
actual HDI score. Which in practice means that minor threshold differences
decide whether birthrates in a country to fall sharply across one decade and
less sharply in another

\- Small islands are given equal weight to China and India in gauging an HDI-
bracket's average birth rate

\- The HDI brackets aren't even _copied_ correctly, and thus many ultra
wealthy territories like Bermuda and Gibraltar are placed in the "low HDI"
bracket. That probably means the model massively underestimates the YoY
decline in birthrates in low development countries (which I suppose at least
works in the opposite direction to incorrect assumptions made about birthrates
dropping to zero)

\- There's really no justification at all for projecting a death rate that
varies between ~1 and ~15 per 1000 as a uniform 8 per 1000, especially not
when data on population age distributions and life expectancies exists. (The
only saving grace is that it isn't that far from the figure for India and
China which have a disproportionate effect on the model)

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tbirrell
_" The table above already shows that birth rates go to zero by 2065."_

Uh.... This seems incorrect. Sure we can extrapolate the declining birthrate
all the way down to zero, but realistically it will level out somewhere since
humans will never stop producing more humans. Granted it might be a lower
birthrate, but never 0.

~~~
himlion
I assume he is talking about net birth rate.

~~~
mfsamuel
He is not, and that is the primary flaw in this analysis.

Estimates that the recent declines in birth rate will continue until 0 annual
births, once the birth rate stops the death rate continues at pace, and kills
everyone eventually.

Flawed in many ways, but that is the biggest mistake. A good example would be
the temperature has dropped 20 degrees in the last month at this rate we will
reach absolute 0 in around 2 years.

~~~
hughes
How would any reasonable person think that all humans will completely stop
having children?

It makes about as much sense to me to continue the trend below zero, and
assume that eventually people start _consuming_ children.

~~~
merkleee
Hey, it worked for interest rates.

~~~
hughes
Zero or negative interest rates can still spur economic growth, unlike birth
rates.

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mywittyname
The author's models for population growth are too rudimentary to be accurate
over more than one or two decades. I find it really hard to believe that the
growth rate for countries will maintain a constant value for the next few
centuries.

~~~
ProAm
Why?

~~~
legodt
There are near infinite factors influencing birth rate that are all
interconnected. No model can accurately account for all of this, but the
models linked don't even attempt to cut very deeply.

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jakozaur
[http://www.economist.com/news/international/21619986-un-
stud...](http://www.economist.com/news/international/21619986-un-study-sparks-
fears-population-explosion-alarm-misplaced-dont-panic)

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kobeya
What if people aren't dying in 2065?

~~~
Udo
That's a huge "what if", on top of what's already an impossible-to-predict
situation. But if we're going to entertain this, we should also factor in the
other circumstances that are likely to come with this scenario:

I spent a chunk of my life adjacent to bio/med research and my conclusion is
radical life extension by purely biological means will probably remain
unfeasible. Genetically, we're millions of years worth of horribly
interdependent spaghetti code, there is no fixing this mess. So - barring the
option to upload yourself to silicon - death won't be obsolete by 2065.

However we might see some _very, very_ moderate increases in life expectancy
across the board, even in comparatively poor nations, as long as they're not
living in abject poverty. This would be cause for concern, but data from
industrialized nations suggest a major regression in births once a population
becomes (somewhat) wealthy and healthy.

The desire to procreate boundlessly may very well be a deep-seated instinct
triggered by living in precarious environments. If dying slows down, it's
because of improved living standards and medical care, the same things that
stop over-procreation.

It seems to me that in order to control Earth's population, we need to address
poverty, which incidentally would solve a huge slew of other humanitarian and
ecological problems.

~~~
kobeya
First, I don't think you are adequately compensating for the availability of
new technologies, such as medical molecular nanotechnology, which we will
certainly have by 2065. The entire approach to medicine that we use now is
likely to be obsoleted in that time frame, leading to the eradication of most
terminal diseases.

Second, one doesn't have to eliminate biological death entirely to muck up
those forecasts. We know from super-centenarians that those who are lucky
enough to not suffer any life threatening conditions nevertheless kick the
bucket around age 120. Even if that's not fixed by 2065, it's almost double
the average life expectancy and that is not factored at all into the OP's
calculations.

Third, birthrates are currently constrained by menopause in women. Most women
don't have more than a few children in the developed world because they are
biologically incapable of having more. And although men have the capability to
have "2nd families" (with another woman later in life after their previous
children are grown), women do not. Defeating/controlling menopause is
therefore more likely to result in either larger families, women choosing to
have a second family at a later stage in life, or women who would have
otherwise missed their chance having a family at all. Again, fertility
advances are not factored into the OP's calculations.

Thus although I could argue that biological immortality is not "unfeasible", I
don't need to. The OP has failed to factor in reasons why the death rate will
go down and the birth rate will go up, making his charts too conservative.

------
earthtolazlo
Why do almost no population projections take climate change into account?
We're rapidly heading towards a much less habitable earth. The projections
I've seen with Africa at a population of 3-4 billion people by 2100 would be
laughable if the whole situation wasn't so damn tragic.

~~~
fleitz
Because current projections don't reach population levels where we exhaust the
capacity of the earth, at best we'd face reduced material wealth.

Why the situation tragic? The universe does not care the sea levels or
temperatures are different from what they were in 1700, just as the universe
does not lament the great oxidation event which wiped out most of the species
inhabiting the planet at the time.

In fact I'd argue that most humans are elated that cyanobacteria 'destroyed'
the planet.

~~~
earthtolazlo
Just about every model shows significant increases in drought and
desertification across most of the world's currently arable land with more
than a couple of degrees of warming, which is the path we're currently on.
Couple that with the fact that most land at far northern latitudes does not
have the soil quality necessary to support large-scale agriculture, and we're
looking at global famines that billions of people are unlikely to survive.

~~~
stcredzero
_we 're looking at global famines that billions of people are unlikely to
survive_

If I were part of a shadowy oligarchic cabal running the world, I'd be willing
to trade-in worldwide chaos for the 21st century equivalent of a Hydraulic
empire, where technologically enabled food production replaces irrigation.

[https://en.wikipedia.org/wiki/Hydraulic_empire](https://en.wikipedia.org/wiki/Hydraulic_empire)

Conspiracy trash aside, if there are billions to be made helping the world
avoid yet another Malthusian disaster, someone will make it.

~~~
eli_gottlieb
>Conspiracy trash aside, if there are billions to be made helping the world
avoid yet another Malthusian disaster, someone will make it.

Who made their millions off the Irish potato famine, other than the British
businesspeople who _caused_ the famine by making Irish food unaffordable to
the Irish?

~~~
fleitz
That's a huge simplification of the famine. The root causes of the famine are
generally attributable to rental law in Ireland and the disincentives it
created towards farmers investing in land and/or farms scaled to the right
size for economies of scale.

------
baq
[https://en.wikipedia.org/wiki/The_Limits_to_Growth](https://en.wikipedia.org/wiki/The_Limits_to_Growth)

not sure if there's anything more to say.

~~~
crpatino
I, too, thought it was related. It is not.

Limits to Growth, whether you agree with their conclusions or not, is an
actual model.

The google docs above is one guy fiting a curve to a bunch of demographic
statistics. There is no real causality there, no attempt to make an
interpretation of the numbers. If he would have done so, he would - as others
have already pointed out - reached the conclusion that: "Since birth rates
decrease when people's lives improve, Progress will make our life so
fulfilling that we will stop having children altogether. Then we will live
happily ever after until we all die of old age."

------
cobookman
Is this such a bad thing. Third world countries are becoming westernized
giving us a continued growth of our markets even though the population might
shrink.

Automation might make manual labor a thing of the past. We might not have
enough jobs or natural resources to support a growing population.

Sadly I feel like studies like this don't take into consideration what a ww3
might do on the world's population long term. We are in an unprecedented time
of peace which might not last to 2065.

~~~
VLM
Also revolution. Automation vs labor vs 1848 and all that. Where there is food
vs where there are hungry mouths are not obligated to match up as they do now.

It would be interesting to analyze food production capability at various
levels of petroleum production and then analyze the probability of those
various levels of petroleum production. The days of powering your oxen with
some acres of hay are long gone, takes quite a few calories of fossil fuels to
generate each calorie of food.

Fossil water is another interesting concept. The east of the USA has more
water than we know what to do with, we'll be OK, but the west currently lives
off rapidly emptying aquifers, and once those are pumped dry, the population
will revert to 1700s to 1800s levels, possibly a little lower. Farmable land
minus aquifer irrigated land, will be an interesting math problem for our
kids.

The roll forward of progress was heavily advertised and seems orderly. The
roll back is going to be completely disorganized and chaotic.

~~~
maxerickson
Energy will be cheaper in 10 years than it has ever been in history.

Progress is pretty likely to continue.

~~~
baq
Can the World Get Richer Forever?

[http://physics.ucsd.edu/do-the-math/2015/03/bbc-questions-
in...](http://physics.ucsd.edu/do-the-math/2015/03/bbc-questions-indefinite-
growth/)

~~~
rokosbasilisk
wow fascinating read.

If global resources are finite, it would explain the drive to colonize space.

~~~
philipkglass
Global resources are finite. The resources of the solar system are finite. The
visible universe is finite.

Finite is not another word for "meager."

Discussions of physical resource limits would be better if pessimistic
prognosticators did not write as if finite-is-meager, and if optimistic
prognosticators did not write as if plentiful-is-infinite.

~~~
rokosbasilisk
finite resources on earth can lead to meagar resources which stop infinite
growth is what I took from that paper.

So we'd have to get resources from elsewhere like asteroid mining or space
colonization.

~~~
philipkglass
_Fundamental properties of nature_ , like the finite speed of light, preclude
infinite growth. To maintain 2% annual growth in human energy consumption, in
just a few thousand years we'd need to have built Dyson swarms around every
star in our galaxy (and beyond). Faster-than-light travel becomes necessary to
sustain that growth rate in less than 2600 years.

The BBC asked a bad question and got an obvious answer. (Maybe the badness and
obviousness aren't apparent up front if you don't have a physical science
background.)

Asking if fixed-percentage economic growth can continue forever is rather like
asking if Moore's Law can continue forever. No, neither can continue forever.
That doesn't mean that things get bad after the growth phase. Somehow both
optimists and pessimists conflate "the end of growth" with "the end of
prosperity." That's ridiculous, IMO. The median citizen is much better off in
low-economic-growth (and negative population growth) Japan than in rapidly
growing Bangladesh.

~~~
rokosbasilisk
Wow thats a good point about japan. Do you know why there is so much
negativity about low growth there ?

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kowdermeister
Can someone enlighten me how did he end up prediction extinction by 2300? I
see words, but it makes no sense to me.

Even if it correctly peaks at 2065, even if it declines, it should stop at a
stable level since most developed nations usually have 1-2 child per family
today. I cannot imagine the next generations doing nothing with a laid back
attitude and slowly let us die out because nobody wants to make babies :)

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stcredzero
Even if you stay within your own solar system, a civilization only slightly
advanced from our own, even without fusion power, could easily sustain a
population of a trillion.

[https://www.youtube.com/watch?v=aDqjK5vR6hE](https://www.youtube.com/watch?v=aDqjK5vR6hE)

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shaunrussell
Faroe Islands with Low HDI?

If you throw out small island nations your trend lines will probably be a lot
more accurate.

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Apocryphon
Does he take into account that population growth has been mostly hyperbolic?

Hyperbolic Growth of the World Population in the Past 12,000 Years:
[https://arxiv.org/pdf/1510.00992](https://arxiv.org/pdf/1510.00992)

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disordinary
It will be interesting if the increase in automation and decrease in working
hours that we're likely to see in the future will lead to a reverse in the
declining birth trends that we've seen in high HDI countries.

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yazaddaruvala
Great video: [https://www.gapminder.org/videos/dont-panic-the-facts-
about-...](https://www.gapminder.org/videos/dont-panic-the-facts-about-
population/)

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kmicklas
Where is this HDI data from? A bunch of countries look misplaced. There is no
way Taiwan is low HDI for example.

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tropo
This assumes uniform gene pools that never change. In other words, it denies
evolution.

For each nation, he extrapolates various existing trends. This wouldn't be too
bad if people within each nation were uniform. They are not. Given the choice
between having children and having other luxury, people do not all make the
same decision. The mental traits that influence this decision are inheritable,
both genetically (brain structure and chemistry) and culturally (religion and
more). It should be obvious that the portion of people who decide to have kids
will increase. We'll be back to exponential growth until we hit real resource
limits and start dying in squalor.

This is unavoidable. Anything done to stop it will be overcome, because those
best at overcoming impediments to reproduction will come to dominate the gene
pool.

