Here’s something that sounds a bit counterintuitive. For as long as humans have measured birth rates, which is at least several hundred years, they’ve been falling.
Every generation of humans has had fewer and fewer children than the previous. This may feel a little confusing because at the same time, the world is more populated than it’s ever been.
Where these trends are headed is cause for concern in decades to come, and some experts are raising red flags now.
Dean Spears is an economic demographer and an associate professor at the University of Texas. He’s also co-author of a new book called “After the Spike: Population, Progress, and the Case for People.”
He joined the Texas Standard to discuss his research findings. Listen to the interview above or read the transcript below.
This transcript has been edited lightly for clarity:
Texas Standard: What exactly explains this notion that we’re seeing birth rates fall and yet the world population continues to grow?
Dean Spears: The likely future for the world population is global depopulation, that each generation will be smaller than the one before. And that’s because birth rates are falling worldwide.
In fact, our numbers have only been growing because we’ve been surviving in greater numbers. Mortality has been falling. But eventually we’ll reach the year when there will be fewer births and deaths, and that’ll be the year we begin to shrink.
And what year are we talking about?
So, nobody knows for sure. Nobody has a crystal ball.
The UN puts it at 2084. Other demography groups put it a little bit earlier, but coming as soon as within the lifetime of a child born today, but not as soon as next week or even next year.
Why do subsequent generations have fewer and fewer children? In fact, I can remember, gosh, going back to when I was a kid, hearing stories on the news about a population explosion – that the Earth wouldn’t have enough room for everyone being born at the time. And now it seems like there are a lot of warnings, heads up, red flags, about the opposite happening.
That’s right. So in 1968, Paul Ehrlich wrote a book about the “population bomb,” warning of overpopulation. But even then, birth rates were falling, and countries around the world were beginning to fall below this important cut point of two kids. Two kids per two adults is the dividing line that will cause depopulation.
And right now, two-thirds of people around the world already live in a country where the birth rate is below two kids per two adults. The three biggest countries – the U.S., China, and India – are all below this cut point.
And when the world as a whole goes below an average of two kids, pretty soon after that is when we’re gonna start to see global depopulation.
I have been already reading stories, particularly analysis coming out of China – and you don’t know exactly where the numbers are, of course, given their economy and command-control economy and all that…
But there’s been concern, supposedly, that population numbers in China have fallen so dramatically it may not be sustainable for their economy. Is that the sort of thing we’re talking about here?
I think for the world as a whole, it’s going to bring unprecedented new challenges to have depopulation.
We’ve never had a future where generation after generation is getting smaller for the world as whole. All the progress that we’ve achieved, the improvements in living standards and life expectancy and infant mortality, all of that has come in a time when the world population has been growing quickly.
And so we shouldn’t necessarily count that we can count on that we can upset that apple cart and know what’s going to happen. Nobody has a break. There’s no sort of automatic stabilizer that once depopulation begins, we can be confident about where it’s going to land or even if the decline is going to stop.
Well, give me a scenario. If someone’s listening to us talking right now, I mean, they may say 2080’s a long way off. What does this mean for us now? What does it mean in the future? Give me a scenario that you’re concerned about with depopulation.
So here’s one way to think about it. Over the past hundred years, the size of the world population has quadrupled, and the decline, once it begins, could be just as fast.
In the U.S., the average birthrate now is 1.6. In Europe, it’s 1.5. In Canada, it is even lower.
So a world of 1.50 kids per two adults is one where the next generation is a quarter smaller. And that means that in a decade, a world like that would fall by about 10% of its size. And in a century, it would fall by two-thirds and that could cause very big changes to our economy, big changes to what we’re able to achieve together.
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Let me just ask what sounds like a crazy question coming out of my mouth. Is it possible humans could be on a track to extinction if we’re taking it way down line?
Well, if birth rates never go up, then each generation would be smaller than the one before and eventually something big would break.
Now, I think that’s far enough out that we can’t predict it exactly, but we know that there are nearer-term consequences that would matter, because people are good for one another. We all build on the discoveries and innovations of one another, that’s why lives today are better than before.
Compared with 50 years ago, life expectancy is greater in every country. Three of every four children who would have died back then now live, and that’s because of the progress we’ve made together, the discoveries and the science that we’ve done together.
If there just aren’t as many of us contributing, then we won’t be able to continue that sort of progress.
Let me ask you again, these sound like crazy questions as I say them, but you hear about people concerned that there aren’t enough people looking for jobs already in some rather sophisticated economies. I’m thinking of Europe in particular.
Are we already seeing the effects of depopulation?
Some countries definitely are. So in South Korea, for example, it’s an average of .7 of a kid for two adults and an economy like that is one where the grandchildren’s generation would be like 12 percent the size of the grandparent’s generation and that’s going to have big effects all over.
Even in the United States, people are talking at universities about how we’re going to plan for cohorts of students that are going to be smaller than what came before.
But the biggest impacts, the most important impacts, are the sorts of long-term progress that we achieve, where science builds on itself – cultural progress, innovation builds on itself. And that’s the sort of thing where we’re just going to achieve less and do less to alleviate poverty, improve living standards, build abundance, than we would be able to in a future where there are more of us contributing.
Well, the obvious question, then, is what, if anything, can be done to mitigate this? Does this basically mean we may see governments saying, “have more kids”?
There are people who feel ready to jump to solutions with some new law or new program, but we’re just beginning to understand this new challenge. And so I think that’s too early.
We’re not going to make progress on getting off the path to depopulation and getting on to a path of stabilization until there’s a bigger consensus that depopulation matters. So I think the first step is to talk about these new facts and understand them and eventually to build some agreement that depopulation won’t solve our problems and may well bring new ones.
