
World Population Growth - gkst
https://ourworldindata.org/world-population-growth/
======
newscracker
If you ever want to feel really old, go to Population.io [1], enter your date
of birth and country (fake it a bit if you wish), and look at how many people
in the world are currently younger than you. This is both fascinating and
shocking even if you enter the information for any smaller children you know
(from the last decade or so).

[1]: [http://population.io](http://population.io)

~~~
sumedh
You are expected to live 40.1 years as a citizen of India

Well that is depressing.

~~~
JoeAltmaier
Not really. You're expected to die in childhood. Survive that, you'll likely
live about as long as anybody anywhere else.

~~~
eru
Close, but not quite. Ie at age 30, the site gives me 53.4 more years in
Germany, and 42.1 in India.

------
Frogolocalypse
One thing that is a little bit off in the analysis is the statement

"China, India and Africa are (and have been for a long time) the most populous
regions in the world"

Actually, according to that data, Africa only overtook Europe in population
between 1980 and 1990. I remember when that happened, because I'd always
assumed Africa had far more people. They will, but it hasn't been for 'a long
time'. It was quite recent really.

~~~
dagaci
Until extremely recently Africa has (with the exception of the Nile delta)
been very under-populated.

Even today it's regions do not rank amongst the most populated regions
[https://en.wikipedia.org/wiki/Population_density](https://en.wikipedia.org/wiki/Population_density)
(with the exception of the Nile delta)

Historically Africa had very little population growth compared to the tiny
population that survived the "out-of-africa" exit.

I would speculate: part of the reasoning for this would be the lack of
domesticable livestock, and why that would occur in the place where humans had
evolved from simple inefficient sapiens.

~~~
hx87
Scarcity of reliably arable land combined with extreme disease burdens
probably have something to do with that.

~~~
Frogolocalypse
It's actually much more simple. It's just urbanization vs rural. As
urbanization increases, population density can increase. Until very recently
Africa was mostly rural.

------
dzdt
Peak population will be a huge paradigm shift for the world economy. For the
entire history of the world we have relied on growth, and the main deiver of
economic growth has been population growth. No more!

~~~
WildUtah
Peak population isn't coming in the next few centuries. The 2008 UN data these
charts are based on had mistaken data on African growth. African fertility is
much higher than expected then and continues not to fall.

The later 2100s in these charts now look to add several more billion and
growing, almost all in Africa. Or from Africa; migration from poorer and
overcrowded countries means Europe will probably be majority African by 2100
and have several hundred million more than shown in these charts also.

The post-2008 revisions of UN projections are quite sobering about the future
and sustainability of humanity. We are not on a path to sustainability. We are
cratering full speed toward a potential Great Filter.

~~~
weatherlight
I really don't think earth is going to be able to support 9 billion people
without some sort of dramatic paradigm shift in the way, as a species, we
consume things

~~~
davidiach
9 billion is 1.6 billion more people than we have today. What dramatic
paradigm shift do we need for the earth to be able to support such a modest
increase?

~~~
crpatino
It would be a "modest increase" if we had spare carrying capacity. Instead,
what we have now is a situation that is going from bad to worse, but since the
crisis is unfolding in slow motion, most people do not recognize it as such;
after all, most people alive today have either never seen what a good
situation looks like, or where too young to grasp the meaning of the changes
they observed back then.

The (human) carrying capacity of Earth was estimated to be around 2 billion,
which was surpased sometime in the late 1920's. Contrary to other comments
here, that does not mean that after you hit population 2,000,000,0001 we all
die (we clearly did not). Instead, what it means is that given the
technological level we had at that time, we'd consume renewable resourses
faster than they can renew themselves, and we'd also produce waste faster than
the environment can degrade it. Otherwise, more than 2B people would cause
environmental degradation, which would itself reduce the carrying capacity in
the long term.

Please note this definition is tied with humans technological level. It is not
set in stone, since we have some degree of control over our impact in the
environment, and we have the ability to use the same resources in a more
efficient way. The big tragedy of 20th century is that this fact was not
recognized but for a handful of theorists, and therefore it was not a
political and economic goal to explicitly manage the carrying capacity of
Earth. As of 2016, the situation is still the same.

By example, we gained a bunch of technologies that allows us to do the same
stuff more efficiently. Given explicit economic incentives, we might have...
maybe doubled our carrying capacity (CC=4B). Unfortunatelly, because this was
not a goal itself, we engaged in a buch of economic practices that negated
much of this benefits, so if we are generous these might have been reduced by
half (e.g. CC=3B). Also given that population growth was not arrested back in
the 1970's, but only slowed down, the carrying capacity has not improved at
all (CC=2B).

Currently, environmental degradation is going in overdrive. We have lost a lot
of time, and the resources we need to make an orderly transition are already
commited to keep the system going. Population will go down, one way or the
other. I don't believe in a single sharp die off many apocalyptic thinkers
profetize, but adding and extra 1.6B mouths to feed will make the downward
tendency of the curve more steeper than it needs to be.

~~~
hx87
A couple of questions about your numbers:

> was estimated to be around 2 billion

By whom? A source would be nice, which is why I generally refrain from using
passive tense when stating facts.

> Also given that population growth was not arrested back in the 1970's, but
> only slowed down, the carrying capacity has not improved at all

How exactly does population growth affect carrying capacity? If I have a car
with 7 seats, its passenger capacity is the same whether I have no passengers
or 6 passengers. If population is an intrinsic factor in carrying capacity,
then whatever definition of carrying capacity you are using is inadequate.

~~~
crpatino
Ok, this are complex questions... but I will try to address them as best as I
can.

1\. The guy who first came with the 2 Billion figure in the 1920s was the
scientist Raymond Pearl, though the copncept of 'carrying capacity' as we
understand it today did not exist. Pearl's work was for the most part
statistic/economic; It was Eugine Odum who later picked up that earlier work
in the 1950s and applied it to the ecology concept of 'carrying capacity'
which was independently developed by the observation of animals in natural
environments. You can check the standard form in Odum's textbook "Fundamentals
of Ecology".

The problem with the original formulation for Carrying Capacity is that it is
assumed to be fixed, because animal behavior is governed mostly by insticts.
Humans, even if ultimately subject to the Laws of Nature, can show much wider
variations in behavior due to culture, availability of technology and many
other factors. According to the wikipedia page, UN has several estimations of
current carrying capacity, and they vary widely (From 4 to 11B) depending on
each researcher biases and methodology.

I personally assume that the results in the higher end of the spectrum come
from cornucopians that fail to take into account the economic and political
presures that get in the way of implementing the (theoretically) optimal
solutions, and therefore assume that actual carrying capacity is closer to the
4-5B range... but then, it's my own bias speaking there.

2\. Other concept you can take from Odum is that long term carrying capacity
can be eroded by organisims that happen to find a short term way to reproduce
beyond the current carrying capacity of the ecosystem they belong to. This is
what I was talking about in my previous msg, though I admit it sounds a bit
convoluted and ranty in retrospective.

If you have a 7 seat car and you usually drive around with 10 or more people
on it, (or with merely 5 fraternity bros that usually behave like baboons on
meth) someone is eventually going to break one of the seats - probably the
copilot one, which happens to be the least robust one. Then, you end up with a
6 seat car, at least for the lenght of the time that it takes you to fix it.
And if you do not fix the seat but keep driving around with the same people on
board, you are going to break another seat, and another.

~~~
hx87
Thanks for the background info, and I think you have a good point about
carrying capacity degradation. I don't think "degradation" is a single
variable though--it's a trade off current well-being, future well-being, and
for a lack of a better word, "nature". We can absolutely provide a high
standard of living for 9-11 billion people, but to do so we have to discard
our desire to "preserve" the world as it is and actively take control of it to
a far greater extent than we do now, i.e. large scale geoengineering.

------
dharma1
In a large part thanks to this guy, who invented a process for extracting
nitrogen from the atmosphere - an invention that now feeds half the Earth's
human population.

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

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

Cheers, Fritz

~~~
pmoriarty
Radiolab had a great episode on Haber:

[http://www.radiolab.org/story/180132-how-do-you-solve-
proble...](http://www.radiolab.org/story/180132-how-do-you-solve-problem-
fritz-haber/)

~~~
dharma1
that was a great listen, thanks

------
Zigurd
This paper
[http://na.unep.net/geas/archive/pdfs/geas_jun_12_carrying_ca...](http://na.unep.net/geas/archive/pdfs/geas_jun_12_carrying_capacity.pdf)
by a UN group surveyed studies of the "carrying capacity" of the Earth. The
bad news is that the largest number of studies say we are near the bounds of
capacity. Worse, many studies say we have overshot sustainable capacity.

But there many studies that claim carrying capacity is much higher than
current population, and that the projected 16 billion simultaneous living
humans is within capacity.

It seems like whether we have a soft landing at the end of the oil age could
dominate any calculation. The ability of renewables to scale up is only just
crept past the starting line of a long, but necessarily urgent race. I'm not
very enthusiastic about the odds.

------
sytelus
As population is one of the indicative of productivity (although a weak one),
you can see how many big events were driven by population growth. For example,

\- During World War II, US had more people then Germany, France and UK
combined. This certainly enabled deployment of massive armies on many front
and huge amount of weapon production.

\- Japan's population suddenly started rising and overtook many western
countries. Its increased productivity might be the reason why this tiny
country felt it can take on the world.

\- India and China are odd balls. India had massive population since very
early times compared to European countries.

-Somewhere in 1870, US population crossed a threshold and became the most populated western country.

-Population for 2100 AD is estimated at 10 billion.

------
amelius
See also Hans Rosling's TED talk on the subject, [1].

[1]
[https://www.ted.com/talks/hans_rosling_on_global_population_...](https://www.ted.com/talks/hans_rosling_on_global_population_growth/transcript)

------
Symmetry
If there are heritable traits that lead to people having more kids in a
developed world environment then at some point evolution will take over and
we'll start to see exponential growth again.

~~~
WildUtah
Yes. The only way to long run sustainability is central control of population
with mandatory birth limits or unlimited expansion of land area to
extraterrestrial territory.

Otherwise evolution will always exceed its limits and produce a crash. Malthus
explained it all mathematically 200 years ago, even before Darwin documented
the mechanisms.

~~~
b_emery
> The only way to long run sustainability is central control of population
> with mandatory birth limits

This is demonstrably not true. Look at Japan and western Europe: declining
population. Its a function of economic situation (no need for more than 1-3
children) and female reproductive choice. If we give that to the world, the
population problem goes away. The mathematics of population dynamics work for
animals, roughly, but the assumptions don't hold for humans because of the
changes in behavior.

~~~
WildUtah
There are people, even in Japan, that want a whole mess of children. That
preference is heritable. Each generation has more of these people because
they're the ones that reproduce.

Eventually those fertile and natal enthusiasts will dominate the population
and exponential growth resumes. The current situation is a temporary response
to an external shock, specifically to reliable contraception. But Malthusian
conditions will return; Darwinism requires it.

~~~
b_emery
I respectfully disagree. Your assumption about the preference being heritable
is questionable.

~~~
wolfgke
Couldn't it not be a gene but a meme that is inherited, instead?

> Each generation has more of these people because they're the ones that
> reproduce.

I.e. each generation has more of these people since people who see having
children as something positive reproduce and teach these values to their
children.

Being a memetic instead of genetic factor would have the advantage that it is
easier to "unprogram" it, i.e. by having rules/incentives in the society that
discourage reproduction or by education.

------
known
With 15% of its population undernourished, India still has a serious hunger
problem [http://qz.com/807050/with-15-of-its-population-
undernourishe...](http://qz.com/807050/with-15-of-its-population-
undernourished-india-still-has-a-serious-hunger-problem/)

------
AlaskaCasey
With the rise of antibiotic resistant bacteria I wonder if this projection of
exponential growth and then plateau will happen sooner.

~~~
Symmetry
The population was rising before the first antibiotic was discovered so I'm
guessing that it won't make all that much of a difference. In general public
sanitation made a much larger difference in the reduction in death by
infectious disease since the 19th century than medicine has.

~~~
JoeAltmaier
And ironically Public Health is the lowest, least respected medical
specialization. Doctors practicing that earn like plumbers or construction
workers. Yet we all own them our collective health and well-being.

------
sampo
Just a note, in the first figure, the annual population growth rate is shown
as the percentage of the population size at that time, not as absolute growth
rate in number or humans added. Neither is more correct than other, but they
are different ways to present things.

------
skolos
Interesting article, but most graphs would be more readable if they would use
log scale.

~~~
eveningcoffee
Not sure, I think that linear scale is more understood.

My only complaint is that the graph 5 should have been ordered by the
population growth rate because as it is now leave a bit distorted general
picture.

------
Frogolocalypse
All I can say is, if you want to maintain that standard of living in western
democracies, you'd better get used to immigration.

~~~
CalRobert
Can you elaborate?

I'm pretty in favour of open borders as an immigrant myself but that statement
could do with some supporting evidence.

~~~
Lazare
It's not so much a question of evidence as basic math.

Imagine a society with 100 people. A working adult can create 50 widgets per
year, and there's 15 kids and 5 retirees. The economy produce 80 * 50 = 4000
widgets per year, which gives a per capita income of 40 widgets. You can have
whatever tax, welfare, or income redistribution policies you like, but there's
only 4000 widgets to go around.

Great. Now let's say 5 new kids are born, the 15 existing kids become adults,
30 adults retire, and the 5 existing retirees die. Bonus: we got 3% better at
making widgets, so a working adult makes 51.5 widgets. We now have 100 people,
5 kids, 30 retirees, and 65 working adults. Total widget production = 65 *
51.5 = 3,347.5 widgets per year, or a per capita income of ~33.5 widgets.
Again, policies can change the distribution, but not the total number.

What we're seeing is that if an aging workforce lowers the overall workforce
participation rate, _as a society_ , we get poorer. If productivity increases,
_as a society_ we get richer. It's just a question of which change is larger,
and in the US (and Europe, and much of Asia) the answer is the aging
workforce. The demographics are clear and brutal.

The most critical metric is the ratio of current workers to retirees; that
number is climbing and is going to continue without a policy change that
somehow reduces the number of retirees, or increases the numbers of workers.
Large scale skilled immigration _might_ do the latter, but failing that, we're
basically out of ideas.

This article spells it out fairly nicely I think:
[https://www.bloomberg.com/view/articles/2016-10-10/innovatio...](https://www.bloomberg.com/view/articles/2016-10-10/innovation-
falls-and-retirees-pay-the-price)

~~~
agd
What you're describing is a pyramid scheme. Get more and more new people in to
pay for those already there. If immigration falls or stop rising you suddenly
have a problem.

A more robust, sustainable solution is to improve productivity via other means
(including automation).

~~~
jackmott
or just be ok with having less shit.

~~~
logfromblammo
...or murder the retirees, and take their widgets.

The apparently abhorrent option is still an option, if you get desperate
enough.

