Why the world’s population is heading for collapse

Starting with what's actually happened, Mike. Now, the replacement rate is a. number to to keep in mind. It's it's the. number of children that women need to. have in order to keep the population. stable. Talk us through what we've seen. um with global fertility rates around. the world in recent decades. >> Basically, what we've seen over the last. few decades is rich countries fertility. rates falling. Uh you've seen that. especially clearly in in East Asia. you. know, you'd have to have been living. under a rock to have not heard this. about Japan, South Korea, China, but.

it's a lot of rich countries as well. Really, all of the the world's rich. countries, but the really interesting. trend, I think, uh, in recent years is. the number of much lower income. countries that are starting to fall. below that replacement level. You can. see on the chart, India there, not a. rich country at all. India had a a. fertility rate of about three and a half. at the turn of the century. It had a. fertility rate six years ago. It's now. uh sub replacement rate. It's true of. most of uh South America. It's true of a.

large part of the rest of the world. And. really the only countries with uh above. replacement fertility rates now are in. Central Asia. There's a big sweep of. countries there and in subsahara and. Africa where you still get some very. high fertility rates but it's an. increasingly small group of countries. that that are actually above that 2.1. level. >> and it's about two twothirds of the. global population there on the left. below 2.1 so most of the world now. >> how does this then translate into what.

to expect for the global population over. the next over the course of this century. Henry the UN does some projections right. >> yes absolutely uh so obviously If the. lower your uh fertility rate, your to. your total fertility rate falls, the uh. faster your population is going to uh. fall. The global population is still. growing at the moment. It's still going. to grow for several decades. And uh what. the UN does is is project forward. fertility and say, okay, when's peak.

population going to be? And it says that. peak population is going to be in the. 2080s. It's going to be uh about 10. billion. And here's the chart of their. their baseline number. But fertility. rate assumptions behind this chart are. obviously really hard uh to make. And. our colleague Corbyn Duncan looked into. them and wrote a piece not long long ago. about this and pointed out that in the. places where fertility has fallen really. low like South Korea, the UN assumes. that fertility will pretty much. immediately start recovering. And in.

other places where it's not so low but. still below fertility rate like the. United States, it says that fertility is. is going to stop falling. And that's. what produces that line. But of course, you can't say for sure that what's been. happening recently is just going to all. of a sudden stop, let alone recover. So. the exercise we went through was saying, okay, let's see what happens if you say. that the current fall in fertility. carries on first for five years. Well, that blue line is what what happens to. global population if uh if current.

trends go on for five years. You bring. for forward the peak in global. population to about 2070. What happens. though if you say okay current trends in. fertility continue for 15 years while. you bring it forward even closer uh to60. and then our last line on this chart is. about 25 years of falling fertility from. this point and you can see you're. creeping gradually closer to midentury. and the other thing to say about that is. of course this is this is at a global. level if you apply that kind of.

assumption to the worst affected places. in East Asia then you know South Korea. might lose a fifth of its population by. mid-century roughly if things continue. as they are. So you you know we are. going to see over the next few decades. us approach this peaku population. position globally which is really. remarkable because the global population. hasn't fallen since the black death. >> Wow. Okay. So a once in several. centuries uh moment may be approaching. Just one question. What is there any.

justification for expecting the. fertility rate to come back up as as the. UN does? Well, it has happened before uh. countries uh that the US was below. replacement fertility or fell below in. the 70s and 80s and then it did rebound. I think what uh makes me pessimistic if. you want to frame it like that about uh. fertility recovering is that you know. what we're saying is a global. phenomenon. It seems to go across. cultures, seems to go across economies.

and we don't have a firm handle on. precisely what is causing it. it seems. to be a kind of whole of society thing. Um, and so predicting things will just. get better because, you know, we we. assume there'll be mean reversion, I. think, strikes me as a little bit uh. naive. So, it's a really big call that's. being made there in in the UN. projections and um it might be that. there's a timing thing that's going on. as as women are having children later, you have cohorts having children a bit. later and so there may be a bit of a. correction in the fertility rates, but.

it's a big call to to assume that around. the world rates are going to start going. up. Let's dig a little deeper into why. fertility rates have fallen. Um Mike, you you talked about the fact that, you. know, something that may not have quite. sunk in is that you're seeing um the. fertility transition not just in rich. places, but in poor places. Now, also in. a lot of people's minds, there might be. this idea that um what's happened to. fertility rates reflects what we've seen. among more educated and and richer. women. But actually, this is a much more.

broad-based trend, isn't it? >> Absolutely. In the same sense that. you're seeing that convergence across. countries with very very different. income levels in the the original chart, you're seeing a convergence within. economies as well at different income. levels uh for for parents, for mothers. especially. What people would have. expected to be normal from the the 20th. century was actually very unusual by. sort of deep historical standards. So. historically, if you go back further and. further the the norm was always that.

rich women had more children than poor. women. you could afford the resources to. have more children, so you did. Poor. women couldn't and so they didn't. That. changed in the 20th century and you saw. poorer and less educated women having. more children than highly educated and. richer women. That has now changed. significantly and you've seen a. convergence across income levels are. sort of balancing out. You look at the. US for example, more than half of the. decline in fertility in the US since. 1990 has been down to mothers under 19.

having fewer children. This is obviously. something that you know is a sort of. social and political goal. It's not. something uh that people didn't want to. happen. You've seen that balancing out. and actually now rich and highly. educated women in the US have slightly. more children than uh some of the lower. income groups. So sort of interesting. change there. But yeah, I think what. you're seeing is a kind of uh. convergence of lifestyle desire. Um so. you're seeing a convergence of interest. That means it's pulling the aggregate.

fertility rate down from the lower end. of the income distribution. And this. seems to be happening uh all over the. world. It's not just the US. It's not. just rich countries either. There is a. convergence across the income uh scale. pretty much globally. >> I find that stat absolutely astounding. I have to say that in the US half of the. fertility decline is essentially the. loss of teen pregnancies because it runs. up so much against the kind of. stereotypical explanation that people. have in their mind that this is about. career women not having children when in.

actual fact uh women in their 30s. college and college educated women. especially they're having children. slightly later I think the uh number our. colleague Karen Richmond Jones reported. was 28 to 30 for the first births among. college educated women in the US. Uh so. it's it's happening slightly later. Uh. but it hasn't really gone down uh uh uh. much at all and it's concentrated in. these these younger less educated age. groups where the trade-offs are much. more complicated because if you go back.

to the 1990s then of course governments. were desperate to reduce the number of. teen pregnancies. So now you have this. phenomenon that is portrayed more often. than not as a problem. Uh but of course. in large part it reflects the success of. of of that campaign.