A world with 2 billion people would be decaying, poor, brutal, violent, hopeless.
A world with 100 billion people would be dynamic, rich, innovative, peaceful, hopeful.
I’ll prove that to you today.
In last week’s article, I explained how the Earth can carry 100B people or more. There were a lot of comments, but today I want to address the biggest fear: Maybe we can grow to 100B humans, but the world would be a worse place to live. If we shrink the population, the world would be better off!
That is the misconception I’ll address today. Later this week, I’ll cover the other concerns:
Do people really stop having children because of the environment and fears of population growth?
Why is it ethical to want society to grow?
Why would that maximize individual happiness?
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The big worry that people have is that more people would make the world a horrible place. I’m sure you’ve heard this type of argument: “We’re only 8 billion, and the Earth is already going to shit, forests are being cut down, global temperatures are spiking, war and politics are tearing us apart. How can we put more people on Earth under these conditions?!”
In economics, this is called a congestion effect. When you’re the only one using a road, you move fast and are happy. But if there are a lot of people, you end up in a jam, and you’re miserable. People think the world is like that: It suffers from congestion, and therefore, more people are bad.
This is intuitive, but wrong. The congestion effect is real, but it’s not the only effect. There are other effects that counterbalance congestion. The question becomes: On balance, does having more people make everyone better or worse off? When we look into it, we realize it makes people better off.
So let’s first look at the positive side of a bigger population, and then look at the negative.
We can conclude that more people bring more happiness for two reasons:
This is what has happened in the past
Looking at first principles
Let’s do each.
a. History’s Take
The world population has been growing rapidly.
And with this population growth has come more happiness and comfort. Fewer people die in wars.
Or from crime.
Child mortality has dropped from nearly 50% to near 0%.
Life expectancy has shot up.
We are wealthier.
We work less.
The share of the world population that lives in poverty has shrunk dramatically.
And much more: There are fewer infections, fewer diseases, fewer accidents. There is more racial equality, and slavery is nearly abolished. There’s more sexual equality, and women are more free and have more independence and income than ever before. Everyone has instant access to all the knowledge in the world, in their own language, via the internet. We can go anywhere, whenever we want.
So historically, the amount of people and happiness have grown together. Therefore, the safest prediction is to assume this will continue: Overall, we will be better off in the future.
But of course, correlation is not causation. So let’s look at first principles.
b. Fundamental Reasons Why More People = More Happy People
Specialization
You probably know that the more people there are, the more they can specialize. In a world with 100 humans, most of us would need to be farmers. But in a world with 8 billion humans, some of us can specialize in producing shoes while others focus on producing corn. Both groups are more productive as a result, which yields lower costs and lower prices for consumers.
Innovation
This specialization allows more people to do research, which leads to ongoing innovation. For example, since there are hundreds of cancer variants, I’m glad there are thousands of researchers trying to find a cure for it. As a creator, I’m very glad that nearly every question I have while researching topics has some answer thanks to the publication of discoveries by academics. Even obscure topics like the logistics of Roman armies have dedicated experts. Whenever I run into a question that nobody has answered, I feel the pain. And when I stumble upon a small niche that only a handful of people have considered, I’m thankful for the fact that we’re 8 billion people and not one billion. For example, there are only a few scientists who study sulfate injection into the stratosphere—the most likely short-term solution to global warming. Would we have discovered that if there were only 4 billion of us?
I’m glad there are thousands of people working to improve our solar panels, our batteries, our windmills, our computers, our AI. The more people we are, the more we can specialize, the more we can innovate, and the better the world will be.1
My own job would be impossible in a smaller world, because there would not be enough kind and curious souls to pay a premium subscription to Uncharted Territories. A smaller world would not have my voice in it.
Population growth is one of the major factors that has driven humanity’s development. A world with a growing population increases specialization and wealth. A dwindling population stops it.
Economies of Scale
The more people there are, the more we can produce, and the cheaper everything becomes. Producing billions of tons of milk makes every liter very cheap. If the world’s population were smaller, Apple would sell fewer iPhones, it would need to amortize its facilities and design across fewer customers, and every iPhone would be more expensive. There would also be fewer buyers, which would in turn reduce economies of scale. And higher prices would mean more inequality: A world with fewer people is one where a smaller share of those remaining have an iPhone (or any smartphone).
Learning Curve & Experience
We make things cheaper because of economies of scale, but also because of learning curves. A big nuclear power plant is more efficient than a small one simply because it is bigger. But we can also make items cheaper by selling more units, which gives us more opportunities to learn.
This is Wright’s Law, which notes that every time we double the production of some goods, their cost falls by a consistent amount. For solar panels and batteries, it’s about 20%. This happens across industries.
Size-Induced Investment
If a small town grows enough to pass a certain threshold, it can get a hospital that it would never otherwise have.
For new companies, it’s always easier to capture new customers than steal them from the competition. So if a market is growing at 2% annually because of increased population, a new competitor might be interested in entering the market to capture some of these people. This new company might offer better goods or services than the existing players.
Conversely, a shrinking population doesn’t justify new investment. A shrinking market means existing companies die or consolidate, reducing competition, leaving less choice to those remaining, and eliminating incentives to upgrade existing services and equipment.
In a world with a growing population, we always have more people to serve, so there’s an incentive to increase scale and create new markets. As we do, we invest more in building, and the more we have, the better off everybody is. When the population shrinks, these incentives disappear.
Network Effects
A group of three people can only have three connections. A group of six people can have 15 connections. The value of networks is linked to the number of connections, so as a network grows, its value explodes. This is Metcalfe’s Law, and it’s the reason why the Bell company was so valuable, why Twitter survives despite all the pressure against it, why the Internet is so immensely valuable, and why people flock to cities.
Metcalfe’s Law states that the value of a network grows with the square of its nodes. So when we grow the world’s population from 10B to 100B, we are 10xing the population, but we are 100xing the value of their connections.
A Shrinking World Is a Conflict World
In summary, factors like network effects, economies of scale, learning curves, specialization, innovation, and others mean that a growing population makes every person richer. Conversely, a shrinking population makes every person poorer.
We’ve gotten used to a world getting richer every year at a pace of 1.5-2% growth of GDP per capita. This has happened for 150 years now. We take it for granted. We don’t realize how much our prosperity and the peace it has brought depend on this. But a big reason why this has been the case is simply because the population has been growing. A world growing to 100B people is a world with continued economic growth.
Conversely, if the population starts shrinking, GDP per capita will probably shrink. There would not just be fewer people—all those remaining would be poorer, too! Do you know what such a world looks like? It’s a world where the pie is not growing.
How do you progress in a shrinking world?
By taking from others.
And what would that look like?
A world where theft, corruption, war, inequality, cheating, and conflict in general are more common.
This is not a world I’d like to live in.
All the upsides of population growth must be balanced out with the downside: congestion costs. People mainly fear five types:
Being more physically crowded
More competition for land, whether for housing, business or tourism
Failing transportation infrastructure
Diseases
Damage to the environment
Let’s take them one by one.
a. How Crowded Would We Be?
I talked about this in last week’s article, but I left some of the picture to your imagination, and some people lack it, so let’s paint it more clearly.
100 billion people would fit in Algeria. That doesn’t mean we’d all go live in Algeria! Similarly, the world would fit 100B people if it was like the Netherlands, but that doesn’t mean we would all live like in the Netherlands!
Paris has a population density of 21k people per km2. The world has 141 million km2 of land, and only 1 million km2 are urban and built up with infrastructure. If that million km2 of urbanized land today was inhabited like Paris, that’s 20 billion people. Think about it! If we make the world as nice as Paris, we would more than double our world population!
And this is despite the fact that Paris has a limit on the height of buildings! Most buildings have a limit of 6-7 floors. If you tripled the allowed height, that would only get you about 20 floors, and that would get us to 60B people! Without increasing the urban land at all!
Now let’s imagine we use 5% of habitable land instead of 1%. That would get us room for 300B humans!
And here I’m not even assuming that we can reclaim barren land, which we could thanks to cheap energy and desalination, as I outlined here.
Note that 45% of the land is dedicated to agriculture: about 14% to crops and 30% to livestock. That amount could be dramatically reduced through higher-density agriculture.
And not everybody would need to live like in Paris! Some people might live in hyperdense places like the old Kowloon Walled City, which held nearly 2 million people per km2.2 Many others would live in lower-density places like Houston. What we would probably have is:
A few megacities with the majority of the world’s population. Places like Shanghai, Beijing, Shenzhen, Singapore, Bangkok, Tokyo, Mexico City, New York, Los Angeles, Madrid, Paris, London, Dubai… The megalopolises of the future could each hold hundreds of millions of people.
Many of these cities would have one or more very dense centers, with less and less density as you move away from downtown.
Most of the other cities we know today would grow in height and extension. Whereas Las Vegas is in the middle of the desert today, it could be much bigger, with other cities nearby springing up.
Some agricultural land from today would remain, but a bit would be reclaimed for urban development. A huge chunk would be reclaimed for nature.3
Here’s another way to visualize this: Consider the cities you know and love. Double their radius4 and triple their average building height. That’s it. That’s a 100B world! Doubling the radius of cities multiplies their surface area by 4, and tripling average building height gets you 3x density. That’s enough to 12x our current population, from 8 to 100B!
So it’s not like this would be an urban apocalyptic nightmare. It would be very much like the places in the world you know and love today, except buildings would be taller, there would be more urban land, and today’s small cities would become more like the big cities we know, encroaching on current suburban agricultural land. New settlements would appear in places like farmland and deserts.
Would the streets be crowded? Well, if your expectation of ideal street crowding is US suburban sprawl, then yes they would. But after living in the US and Europe, I can tell you that that type of street density is not conducive to happy street life. Americans who have lived abroad understand this. Having lived in Paris, Milan, and Madrid, I believe that the street density in those places makes them beautiful. It makes the streets alive.
My trips to downtown Hong Kong, Shanghai, and Tokyo, where street density is even higher, have shown me that these places offer a better world than the experience most Americans have today.
And it’s not just more human beings on the streets. These people are clients, so many more businesses would be possible. We could create niche experiences that are inconceivable today, simply because there would be enough customers to make them sustainable. If you’ve ever explored the amazing businesses that line Tokyo’s streets, you’ll know how amazing it would be to have an explosion of such experiences around the world.
And if you don’t like it, you can still live in rural areas! They would still exist!
b. How Expensive Would Land Be?
Land would absolutely be more expensive. Real estate would cost much more. But that would primarily be true in the big cities. In rural areas, land would remain cheap. If you wanted to escape the cities, you could.
But we must realize that the current cost of real estate is more driven by regulation than by a lack of land. A world where 100-story buildings are allowed is one where many people can have large apartments for their families, including multi-story ones.
That said, and given that remote work is likely going to be ever more common, and that countries will continue to compete for high-income earners, it will be much easier for people to move around, and real estate prices will certainly be a factor. Higher competition across cities is likely to drive prices down.
Coastal tourism would certainly be much much more expensive, because there would be more demand for it, but supply of coastal land is hard to increase. It’s not impossible, though:
And we’re not just limited to creating more coastline on the sea. We can create it on land, too, by creating more seas:
The queues to the Eiffel Tower or to Mount Everest would certainly be longer, and it would cost much more to access these places. But that would spur other places to innovate and create great experiences for people to visit.
So yes, housing and tourism would probably account for a higher share of spending. But every other cost would plummet thanks to more economic efficiency and innovation, so all in all we would be vastly richer.
c. Would Transportation Falter?
Where is transportation infrastructure better, in rural areas or urban ones?
Is it easier to move around in Tokyo and Madrid, or your average small city (eg, say, a city with 200k inhabitants)?
Transportation infrastructure is highly dependent on local politics, but holding that factor constant, transportation benefits from higher density. A subway line benefits tremendously when it doubles its passengers, because revenue doubles but costs increase much more slowly.5 The same is true for most transportation infrastructure: Its value is determined by network effects, and therefore grows exponentially, while the costs that grow are the variable costs of maintenance and service and expansions, leaving the heavy fixed costs to be amortized across many more customers.
And that’s not even taking into account amazing innovations like hyperloops, self-driving cars, or faster-than-sound transportation. All these innovations will make transportation orders of magnitude more efficient.
So odds are that our transportation infrastructure would get better, not worse!
d. Would Diseases Spread?
This is another perfect example where people only project the bad to increase, without projecting the good.
If nothing else changed, a world with 100B people living closer to each other than today would most certainly be more susceptible to fast-spreading disease.
Moreover, a world with 100B people and more wilderness is one where humans have more frequent contact with wild animals, increasing the odds of pathogens jumping from them to humans.6
But there are other factors to consider that make me think we would be safer from disease.
If the COVID pandemic had a silver lining, it’s that we woke up to the threat of contagious respiratory diseases. These have particular import because our mouth and nose ejections are the only ones we can involuntarily and easily project onto other humans. Not only that, but respiratory viruses have evolved to hijack our natural ability to cough and sneeze for their own contagion benefit. Nearly all other human responses can be throttled, but those that spread respiratory viruses are much harder to thwart.
So now that we are focusing on respiratory diseases, we are discovering all these mechanisms they use to infect us and spread. We are developing measures against them commensurately.
Not only that, but we’re also realizing some quick wins. For example, UV lights and air filtering are amazing at eliminating these viruses and dramatically reducing airborne infections. And research on respiratory vaccines is in hyperdrive. It’s very likely that we will have a much better grasp on these diseases and how to tackle them in the coming years.
Finally, a world with 100B people will have many more researchers, especially in healthcare. This is a world where diseases become less and less prevalent and worrisome, the way we’ve been repeatedly beating them over the last few centuries. This applies not just to respiratory diseases, but all sorts.7
Looking at the strengths and weaknesses of a 100B society, I think it’s clear that we would have a healthier world.
e. Would the Environment Suffer?
I covered this extensively in the article from last week.
The short answer is that what we’ve done in the past is unlikely to happen in the future, because:
We’ll care more about the environment
We’ll be richer
We’ll need less land for agriculture
Most of the world’s biological diversity is concentrated in a few countries, all of which are reducing their encroachment on wild forests. This process is likely to continue, and as we abandon agricultural land for forests to regrow—like has been done in Europe—biological diversity will improve, not worsen.
Similar arguments are valid for pollution. Go read the article What is the Earth’s carrying capacity?
So where does all this leave us?
Our brains are tricking us. We are machines that evolved to pay attention to immediate threats in a world that changes slowly.
So we tend to consider the problems around us and project them into the future: “If we destroyed our way to where we are today, what will happen if we 10x our population?!”
But that doesn’t take into account how things work and evolve.
With a shrinking population, we would be poorer, more depressed, more pessimistic, and we would fight for a shrinking pie, which would increase conflict, violence, corruption, and crime.
With more population, we would have fewer diseases, better transportation, livelier streets, enriching experiences, more innovation, more money, more peace, less conflict. And more people to enjoy it all.
I want to live in that world.
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I hope you enjoyed this week’s article. The premium article this week will address the other big questions readers have on this topic:
Do people really stop having children because of fears of overpopulation?
Why does more population make every individual happier too, not just overall as a society?
Why is it ethical to want a bigger population, and unethical to want it to shrink?
Isn’t it selfish to only think about humans? Should we worry about the experience of animals and plants?
Subscribe to get it.
1
Mandatory AI caveat, which should be appended to every projection on every topic beyond 4-10 years: Unless AI kills or replaces us all.
2
At an equivalent density to Kowloon Walled City, 100B people would fit in 50k km2, the size of Costa Rica. The city was smaller than a square kilometer though, and held 35k people. It’s just to show extreme environments—which were not that tall though.
3
We would just need to 2-4x our urban land, from 1% to 2-4% of all habitable land. Meanwhile, with more efficient greenhouses and vertical farms, we could easily reduce the 45% of habitable land we dedicate to agriculture. This would likely require regulation, but it’s definitely doable.
4
Not all cities can double their radius. Tokyo and Barcelona for example would have a hard time. But many other places could spring up.
5
You need to double the number of trains, but barely need to make changes to the railways and stations, which are the biggest cost.
6
I’m assuming here that we have more humans and more wilderness as we reclaim some agricultural land for forests. More of both probably means more interaction between them, although this might not be the case if regulation limits access to wilderness drastically.
7
I do worry about bugs having more opportunity to evolve with 100B hosts, and antibiotic resistance developing. But I think bug evolution is likely slower than scientific evolution, especially in a growing world. I think we can likely find fundamental ways to fight bad bugs, so on balance I think things are likely to get better.