Name: 人口統計学者だけど質問ある？ | Tech Support | WIRED Japan
Uploaded: 2025-03-14T09:50:06.000Z
Duration: 30 min 37 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

I'm Jennifer Shuba and I study demographic data.

Let's answer your questions from the internet.

At virillion four, how many people have ever lived on this earth?

So there have been about 108 billion people, as an estimate, who have ever taken a breath on planet earth.

If you went back to, say, year one, there would be about 55 billion people who had ever taken a breath, and there are eight billion people who live on planet earth, 7% of the 108 billion who have ever taken a breath.

Is the majority of the world's population children or adults?

Well, the majority of the world's population is adults.

Even in Africa, which is the youngest region in the world, 54% of the population is adults.

Countries have seen a steady increase in their life expectancy over time.

World population is growing older, and that's because the number of children per woman has gone down.

One way to think about it is the average woman about 50 years ago would have had four children in her lifetime, but the average woman globally today has only two.

So if we think about lining everyone in the planet up from the youngest person to the oldest person, where would the center of gravity be?

The center of gravity has shifted over time as the average number of children per woman has gone down.

At jdcrow13, quiz, what is the fastest-growing minority in America?

If you answered hipster, then you win the prize.

Actually, if you answered Asian Americans, you would win the prize.

They are the fastest-growing minority in the United States, and they're about 7% of the US population.

At benpo234, what are the signature demographics of a red state versus a blue state?

If we think most generally, a red state most often would be more rural, probably have an older population, and is whiter.

Blue state would have more urban areas, ethnically or racially diverse, and probably a younger population.

But you may notice that it doesn't always map that way.

That's why on election night, it wasn't really just enough for us to see the 50 states projected on the screen and try to figure out how the election would turn.

You could start to zoom in and see really different dynamics, like Tennessee, for example, that is relatively a red state across, and then with these little blue dots in the Memphis-Nashville areas.

A state like Maine is the most rural state in the United States, but it still has lots of blue areas, and those are its urban areas.

So if you're talking about a House race or a Senate race, you can see how those sub-state red and blue areas really show up and matter for what a vote looks like.

At Stallman's Beard, is immigration a net positive or negative?

One way we wanna think about it is through an economic lens.

In the United States, immigrants are actually most likely to be of working ages.

The US has a total fertility rate below replacement level of 1.6 children per woman on average, means immigration contributes quite a bit to the growth in the working age population here.

We can see that foreign-born population, very few children under five, very few five to 17 years of age, much more concentrated in terms of 18 to 64, or those working ages.

Versus US-born population, immigration is kind of what propels that overall population growth.

If the US were to stop all immigration right now, not do anything else between now and the end of the century, the US population would shrink by over 30%.

At Venompilled, wants to know why do fertility rates matter?

Well, they matter a lot because they impact its age structure, for example, and of course, its size.

We can actually see this if we look at snapshots in time of a handful of countries in the world today.

Females on this side and males on this side, from age zero all the way up to over 100.

So if we're looking at Ethiopia here, we can see this classic pyramid shape means that it's a population where women have, on average, more than two children.

So the population is a lot more bottom-heavy, which means that there are a lot more younger people in the country there.

If you had one that's fertility rate of four children per woman on average, each generation's twice the size of the one before it.

Versus, if we look at a country like Turkey, you can see that that center of gravity, in terms of ages, is in the middle more.

And that's because they've had close to replacement level fertility rates for a while.

Average number of children of 1.9 per woman.

So we see that that population is growing older.

The bulk of the people would be here of these working ages.

It's not really a population pyramid anymore.

There are lots of older people in this society.

And so you can see this narrowing here at the bottom.

And that just shows you that women of reproductive ages, they're having under-replacement level fertility rates.

If you're in Ethiopia and you're a policymaker, probably one of your bigger concerns is how to build enough schools year after year for all of these young people aging into kindergarten.

And then how to have enough jobs for those who are aging into the workforce.

If you're in Turkey, you're thinking about the working age population, certainly, and their jobs there.

But you also need to be thinking about how, in just a few years, these folks will be moving into retirement ages.

And if you're in Japan, you're thinking about how schools are closing year after year.

You have a much smaller workforce needing to support a growing population of older people.

So age structures, which are affected by fertility rates, really matter for even setting the agenda at the national level.

At Tommy Boyo is the real issue that we have too many humans on the planet.

So in a few hundred years, when the world population is over 50 billion, what will our problems be then?

We will never have a population of 50 billion, at least not anywhere close to it with our trends right now.

Best estimates are somewhere around the year 2080.

And we'll top out at between nine and 10 billion people.

Now we're reasonably certain about this because our trends in fertility rates and mortality rates, they're following a fairly predictable pattern.

The uncertainty comes from really just two things.

One is how fast will fertility rates fall in places where they're currently still high?

And there really aren't that many places in the world where fertility rates are really high.

They're mostly concentrated in a few countries in Sub-Saharan Africa.

We live in a world where there are only eight countries out of 200 something countries where women have five or more children.

That includes Nigeria, for example, which is a pretty big country, keeps global population young.

We have not seen any indication that it's gonna come up in places where it's low.

So I feel pretty confident we'll be hitting a peak of somewhere between nine and 10 billion people, roughly around the year of 2080.

At Hawaiian Pace asks, how can Elon Musk be worried about population decline when Nick Cannon exists?

Elon and Nick Cannon maybe have something in common, which is they might be single-handedly trying to change global trends.

Global population growth has been declining since the 1960s.

You can see this peak here in the mid-1960s.

So that rate of growth is really going down over time.

This is what's happening beneath the surface, while on top we see world population continuing to grow to where we have eight billion today.

So why is Elon Musk worried about declining population?

It's because what's happening right now is the beneath-the-surface trends are starting to catch up to what we actually see on the surface, where there's over 60 countries in the world that have shrinking populations.

So to keep population growth steady, you would wanna replace them with two children.

But in some countries, Singapore, for example, you only have one child born for those two parents.

So you can see how those populations of those countries would start to shrink over time.

And that's happening, especially in a lot of high-income countries.

So the reason why somebody like Elon Musk would be concerned about this is you end up with smaller generations over time, meaning fewer producers and fewer consumers.

At Shuffleupagus, I'm on a road trip right now, and I'm wondering what's up with these empty small towns.

There are a lot of governments who are really worried about this because of what it means for economic vitality or national security.

Obviously one of the world's biggest economies, huge player on the international stage, but also a rapidly shrinking population.

Look at a country like Italy and how many of the villages are depopulating.