Should we be worried about overpopulation or depopulation?

Daniel and Kelly talk to the authors of "After The Spike", who argue that humanity is on a dangerous path to depopulation.

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Episode Transcript

Speaker 1 (00:07):
The average number of children each woman gives birth to
globally has been steadily declining. To some, this is a disaster.
Elon Musk, for example, says that collapsing birth rate is
the biggest danger civilization faces by far, with fourteen children
at last count, he seems to be attempting to avert
this crisis single handedly. Folks concerned with the decline in

(00:31):
birth rates advocate for policies that incentivize having more children.
But on the other hand, a decline in birth rate
is music to the ears of others. As someone who
adores both human beings and nature, I would love to
see living standards rise as population size falls. It seems
reasonable to assume that more humans translates into a greater

(00:53):
environmental impact. So if humans are choosing to have fewer babies,
that sounds like a win win for humans and for nature. Plus,
I've heard humans are going to level out at eight
billion people anyway, so any decline in population size would
be short lived, and anyway, this seems like a problem
for future generations. Right, Why should we start worrying about
population size now? Well, today we're going to talk to

(01:17):
Dean Spears and Michael Jeruso about their recent book After
the Spike, Population Progress and the Case for People. They
are concerned that the future will see a precipitous decline
in human population size, and they want to see us
start taking this problem seriously now so that we have
plenty of time to find compassionate solutions to the problem

(01:38):
before society start to feel the pinch. Welcome to Daniel
and Kelly's Extraordinary Universe.

Speaker 2 (01:56):
Hi. I'm Daniel. I'm a particle physicist and a professor
a you see Irvine, and I have two children and
a dog.

Speaker 1 (02:02):
Hello. I'm Kelly Weener Smith. I study parasites and space
and I have two children, two dogs, seven goats, two cats,
and as of next week, I will have five ducks
and two geese.

Speaker 2 (02:16):
Is that it really how many rats are living on
the property?

Speaker 1 (02:19):
Well, you know, there used to be a lot of them,
but we took care of them. And I know, I
know you and I really like rats, but not when
they're eating the chickens food. And it was just complicated
and it was us or them.

Speaker 2 (02:33):
So my question for you, Kelly is why did you
decide to have two children and not three or seventeen?
And you considered goats part of the Wiener Smith clan.

Speaker 1 (02:44):
I love the goats, but not as much as I
love my kids, and so there's a hierarchy there for sure.

Speaker 2 (02:50):
Wow, species is much Yep, Yes, it's true.

Speaker 1 (02:53):
I like humans. I do like humans a lot. We
decided to have two because after we had the second
one and he was old enough to be like sleeping
a little bit better, I thought to myself, I do
not have the energy to go through those long nights again.
And my second pregnancy was a high risk. I ended
up in the ICU with hypertension after my son was born,

(03:15):
and so I was like, I think my body is
telling me two is good, and yeah, what about you?
Why'd you pick two?

Speaker 2 (03:22):
I feel like two is a special number because it's
the same number as parents in the family, And so
I think people really underestimate, like how much more work
a third child is. And you know, when we talk
to the economists today on the program, they're talking about
these numbers one, two, three, But I really feel like
there's a barrier there past two where it just really
becomes much much harder. And also if you have like

(03:42):
two academics and young careers, and it just didn't seem
plausible for us. Plus every pregnancy for us is high
risk because Katrina is Type one diabetic. Yeah, so it
just felt like more than we could handle.

Speaker 1 (03:53):
So you and I both read the book, and they
do address how difficult and time consuming it is to
have children, also like how beauty full and amazing it is.
And one of their suggestions is that, you know, society
needs to modify in ways that make it easier, you know,
easier to get child cares, or less work for the
moms and for the dads, and just trying to make
the whole thing easier. But I agree, two was a

(04:16):
lot more work than one. And I thought, I thought, well,
I'm already doing this parenting thing. It won't be that
much more. It's a lot more, And I'm still glad
I did it, for sure, But yes, three is to
me conceivable.

Speaker 2 (04:29):
So thank you to all the parents out there having
more than two children and helping us maintain the human population.

Speaker 1 (04:36):
That's right, Yes, it's an important job and needs to
be done well. And so speaking of the human population,
the book that we're talking about today sort of projects
forward what the human population might look like as we
go through multiple generations, and so we wanted to know
what our audience thinks about how many people will be
on the planet in three hundred years, and here are

(04:57):
their answers.

Speaker 3 (04:58):
That's a good question, but realistic unanswable, and my humble opinion,
because there are too many unknown variables that can occur
in three hundred years that could wipe out a portion
of all of humanity, from our own deeds to an
asteroid impact like the size that took out the dinosaurs,
or a combination of things like successive volcanic eruptions, wildly
ballenced anomious tornadoes, and plant earthquakes. So I don't think
the question is realistically answerable.

Speaker 4 (05:19):
So the optimist in me would say that overall population
would be in a slow decline by then, since as
education levels increase around the world and the standard of
living increases around the world, people tend to have fewer
children on average. In fact, they tend to have a

(05:41):
negative birth rate, So I would say.

Speaker 2 (05:44):
One billion individuals.

Speaker 4 (05:45):
I kind of feel like we'd go back down to
something like that. The pessimist in me says that we
blow ourselves up with a nuclear disaster.

Speaker 5 (05:55):
Birth rates in all countries have dropped. I expect in
three hundred years, we will have less population than today.

Speaker 6 (06:04):
It's easy to naively imagine living like the Jetsons three
hundred years from now, but considering the unsustainably outrageous rate
of our populace over consuming all natural resources except sunlight,
I anticipate a bleak existence. For However, many humans can
subsist on what remains. Choosing a number, I doubt even
first order billions.

Speaker 7 (06:24):
Well, I think that in three hundred years there will
be social pressure to just replace yourself. I think with longevity,
people will be living for a very long time and
we will avoid overpopulation.

Speaker 8 (06:40):
I personally think we have a horrible future as a species.
We are terribly overpopulated right now without enough resources. My
guess is in three hundred years they'll probably be less
than ten percent of the population left. Sadly, I don't
think there will be any people lift on planet in

(07:00):
three hundred years.

Speaker 6 (07:02):
We are our own worst enemy, and considering the trajectory
we're going in right now, I would say.

Speaker 2 (07:08):
Less of five percent of the current population, precisely zero.

Speaker 5 (07:13):
There's no way we'll make it that far.

Speaker 2 (07:15):
So, Kelly, why did you pick three hundred years? It's
a really specific timeline.

Speaker 1 (07:20):
Oh. I went to one of the figures in their book,
and I looked at a point where the projected population
size was quite a bit lower, and so I thought,
you know, at this point, people can say up or down,
and according to their projections, the answer should be definitely down.
But I gotta be honest, I did not expect answers
to be so dark dark from our audience. Usually there's

(07:42):
like a bunch of jokes thrown in there, like I
don't know, but here's a poop joke, and I'm like, oh,
I love you guys. But this was like we're probably
gonna blow ourselves up. Yeah, And they're like, oh man,
a couple answers like that, and so wow.

Speaker 2 (07:54):
Well, I don't know. Maybe digging this deep into science,
into physics and biologies made people existential. You know, they
realize how fragile our meat bags are on this tiny
speck of dust we're floating on in this vast universe.
So it's sort of hard in that context to imagine
we're going to be around in three hundred years, three
thousand years, three million years. It seems like incredible we

(08:14):
are here at all.

Speaker 5 (08:15):
Yeah.

Speaker 1 (08:16):
No, I absolutely agree, and I share concerns about what
our species is going to do because we have nuclear
weapons and are we going to like just totally accidentally
blow ourselves up? I hope not, but from a like
resources and population standpoint for anyone who's feeling negative but
would like to have their spirits slightly lifted, I really

(08:36):
liked Not the End of the World by Hanna Richie.
She runs our world in data and so she really
digs into the numbers for a bunch of these resource problems,
and it's like one of my favorite books because I
love the way she addresses these problems with data, and
in the end she decides, look, we can handle this
and it doesn't need to be too catastrophic in terms

(08:57):
of all of us changing our lives, but we do
need to make some changes and here are some suggestions.
And anyway, I really enjoyed her book.

Speaker 2 (09:04):
Awesome. I'll check that out.

Speaker 7 (09:06):
Well.

Speaker 2 (09:06):
Today we're talking about the book After the Spike, Population
Progress and the Case for People by Dean Spears and
Michael GURUSO out today. Go check it out. Kelly and
I both read this book. I really enjoyed it because
I love books that take apart sort of popular misconceptions like,
here's the standard lore everybody believes. Why did you believe that?
Why is that not true? And what's more likely to happen?

(09:28):
And this book does a great job of that. It's
a little bit nerdy and economical and data heavy, but
only as much as you need to convince yourself that
these guys know what they're talking about and the issues
they raise are real issues. It's also fun and their
jokes and as you'll hear in our conversation today, these
guys are good at explaining stuff.

Speaker 1 (09:46):
Yeah, and I also felt like they were sort of
kindred spirits with us because for a lot of the answers, it's, look,
we just we don't know, we don't have the data,
and they're very honest about what we do know what
we don't know. Yeah, and I really appreciate that they're
t taking on this problem because it has sort of
become politicized, as I mentioned in the intro, and I
feel like they might be sort of making themselves targets,

(10:07):
which is maybe why they are so so tied to
their data, the data and their arguments. And anyway, they
make some pretty interesting arguments. And let me go ahead
and give their bio real Quick. Spears and Jeruso are
professors of economics and demography at U t Austin. Jeruso
served as a senior economist in the Biden White House.

(10:27):
Spears runs the nonprofit research Institute for Compassionate Economics, which
helped establish a give well backed newborn health program in India.

Speaker 9 (10:37):
Welcome to the show, guys, Thanks so much for having us.

Speaker 5 (10:40):
Glad to be here.

Speaker 1 (10:41):
My husband Zach has been absolutely raving about your book.
He loved it, so I was excited to have a
chance to read it. So let's jump right in. One
of the things that I like about this book is
that it gets me to think about population size way
differently than I thought about for like, literally all of
my life. So I was born in nineteen eighty two.
When I was born, popular size was about four point

(11:01):
six billion, and it's currently over eight billion. And I'm
an ecologist, so I usually think about population size as
being the thing that kills animals and destroys ecosystems and
stuff like that. So when I started hearing that, you know, oh,
eventually population size is going to go down, that sounded
like good news to me. And so your book was

(11:22):
sort of like mental whiplash for me. So explain to
us why population is going to go down and why
instead of feeling like, oh, this is maybe good news,
why this is something that we should be concerned about.

Speaker 9 (11:34):
So we were also born in the eighties and we
also grew up hearing about overpopulation. But right now, global
depopulation is the most likely future. And what global depopulation
means is that every decade, every generation, the world's population
is going to shrink. That's the path that we're on.
Within a few decades, the world's population will begin to decline.

(11:56):
And there's no reason to think that once that happens,
it'll automatically reverse.

Speaker 5 (12:00):
So a big.

Speaker 9 (12:01):
Question before us is should we welcome that or should
we want something else to happen. But even before that
is why it's happening. And the fundamental explanation is that
birth rates are low and falling. So that's a way
that humans are different from other animals. If you're thinking
about ecology, that humans have cultures in society and decision

(12:23):
making and decide how many children to have. And over
time we've been deciding to have fewer children. And you know,
when I say low birth rates, you might think something
like South Korea where there is zero point seven of
a kid on average for two adults right now. But
actually it would be enough for global depopulation to have
low birth rates like in the US where it's one

(12:45):
point six kids per two adults, or like Texas or
Latin America where it's one point eight, because depopulation will
be the unavoidable consequence of there being fewer than two
children in the next generation to replace two adults in
the last generation. In two thirds of people now live
in a country where the birth rate is below that

(13:06):
two births per two adults average, that would stabilize the population.

Speaker 2 (13:10):
And what exactly is new about that piece of knowledge, Like,
is this something that demographers and economists have known for
a long long time but the general population isn't aware of,
Or have we recently learned something about birth rates? Why
this conflict between our knowledge that birth rates are following
and the general sense among the whole population that the
population is growing out of control.

Speaker 5 (13:30):
Yeah, I think that's a really good question. The fact
of the matter is that falling birth rates are not
some entirely new phenomenon that just popped up on the
scene in the last five or ten years. During this
period of rapid global population growth, you know, over the
last fifty sixty years, that was a period during which
birth rates were already falling. It's just really hard to

(13:52):
see and appreciate that birth rates are falling in a
time when the goal population is spiking up so quickly. Right,
So you mentioned you were born in nineteen eighty, Kelly,
or sorry, nineteen eighty two. I was born in nineteen eighty.
But the birth rate has been falling for a very
long time.

Speaker 1 (14:07):
Ian.

Speaker 5 (14:07):
It's been falling for as long back as we have
good statistics to document it. So birth rates were falling
in France and the seventeen hundreds, birth rates were falling
in other places in Europe in the eighteen hundreds. Birth
rates have been falling for the globe overall for as
long back as we have any good statistics now, like
there have been temporary blips, like the post World War

(14:30):
two baby boom, but on average, over the whole world,
over time frames that span decades rather than individual years
where things might bounce up or down, birth rates have
been falling. And so I just think it's really hard
to come to grips with the idea that even as
the population is rising birth rates have been falling.

Speaker 2 (14:49):
Can you break that down a little bit for those
of us who don't always think in terms of differential equations,
How is it possible for the population to be rising
and the birth rate to be falling?

Speaker 5 (14:57):
Okay, good question. Population changed At the basic level is
the difference between birth rates and death rates. So there's
two ways that population can increase. Births can go up
or deaths can go down. And the revolution that's happened
around the world in the past two centuries has not
been birth rates climbing. It's been death rates falling, and

(15:18):
in particular, the death rates of children falling.

Speaker 2 (15:21):
So that sounds like good news.

Speaker 5 (15:23):
Yay, Yes, that's very good news.

Speaker 3 (15:25):
Yay.

Speaker 5 (15:26):
I mean it's really good news. It's sort of hard
to appreciate from a modern perspective just how awful the
mortality rates of children and babies were not all that
long ago. So a couple hundred years ago, the sort
of the global average for mortality for a kid would
be something like one in three kids dying before age five, right,

(15:49):
And so as we've learned to keep ourselves and our
children alive through better sanitation, through an understanding of the
drum theear of disease, through better water, through better nutrition,
eventually through vaccines later at our history, what that's meant
is that more people have grown up to become adults
and to have children of their own. So the part

(16:10):
of the equation that's been changing this time is that
death rates have been falling and birth rates have been
falling too. It's just that they've been chasing death rates downward.
And the net effect of all of that over the
past one hundred years two hundred years has been just
a skyrocketing of the global population. So, just to put
that in some perspective, in eighteen hundred, there were about

(16:31):
a billion of us worldwide. About a century later, in
nineteen twenty five we passed two billion, and then since then,
in the last hundred years, we've quadrupled to the present
eight point two billion. And all of that action has
been about declining death rates that have been declining faster
than birth rates have been declining.

Speaker 1 (16:48):
And so is the idea that at some point we're
going to max out on what we can do in
terms of reducing death rates, and now the birth rates
are going to start being more important.

Speaker 5 (16:58):
Yes, yes, we're going to in out on what we
can do for minimizing death rates. Thankfully, mortality rates for
children are so low that they're pressing up against a
zero lower bound, so there's just not much more room
for them to fall. Meanwhile, fertility rates continue to fall.

Speaker 2 (17:14):
Can't we all just transform into immortal cyborgs and solve
this problem?

Speaker 5 (17:17):
That would be? That would be that would be.

Speaker 2 (17:21):
Something I love seeing you search or an adjective there?

Speaker 9 (17:26):
Well, I mean, okay, so there is actually there's something
interesting there. I want to jump in on that because
that is a question that we get, which is, could
lower mortality rates solve this problem? We don't mean lower
info mortality rates? What sort of brought us up to
spite people's like what if people just stop dying in
older age and live longer than so, like, what if
instead of dying on average at seventy five or something,

(17:47):
we live twice as long and died at one hundred
and fifty?

Speaker 4 (17:51):
Right?

Speaker 9 (17:51):
Would that be enough to knock us off the path
and make it so it's no longer the case that
depopulation is the most likely future. And they answered that
question is surprisingly no. Now you asked out differential equations
and I won't get into it. But just think of
it as like this. If everybody still has two kids
or one point six kids on average for two adults,

(18:13):
then we're going to have the same phenomenon where the
next generation is smaller than the generation before. A given
generation will live longer, so the number of people alive
and any one time will be greater, but depopulation will
still be what's happening. As generation after generation gets smaller
and smaller.

Speaker 2 (18:29):
You're just stretching out the time scale.

Speaker 9 (18:30):
Befasted exactly, stretching out the timescale. Now it could be
if we live to be one hundred and fifty instead
of living to be seventy five. And also the biology
of reproduction change that instead of having you know, kids
in our twenties and thirties and maybe forties, you had
a couple of kids in your thirties, a couple kids
in your fifties, a couple kids in your seventies. Right

(18:50):
then we would get off the path from depopulation. But
it wouldn't be because we were living longer. It would
still be because we were having more kids. I'll pass,
I don't know, I mean, what are you going to
do with all that time when you're one hundred and
forty and sleep read read we.

Speaker 2 (19:07):
Might need to be cyborgs that to keep up with
our toddlers when we're one hundred and thirty. That does
not sound like a lot of fun.

Speaker 1 (19:13):
That's hard. I've been telling a bunch of my friends
that I read this book and have wanted to like
start conversations with them about it, and a lot of
them will say to me, well, that doesn't match up
with what I've heard. What I've heard is that the
Earth's population is going to settle at eight billion and
we're going to stay there. And a couple people have
said this to me, do you know where that figure
came from? And could you explain why it's wrong?

Speaker 9 (19:36):
Yeah. So I think it's just that people have known
that population growth was slowing, and there's just like a
trope or something that's come out of you know, population
growth is slowing and it's going to hit zero, and
there just isn't a lot of thought about what happens next.
So you might read a newspaper article it says, you know,
demographers that come out with new information that shows that

(19:58):
population growth is slowing in going to hit zero. Yes,
but then what happens next you throw a ball up
into the air, and at some point it's vertical velocity
is going to hit zero. But that's not the end
of the story, right The same force that slowed its
ascent is eventually going to bring it back down. And
I think people just aren't seeing that second side of

(20:19):
the story, that just as falling birth rates have slowed
the growth rate in the population, falling birth rates are
also going to bring the population size down.

Speaker 2 (20:29):
So are you suggesting that we haven't had any sort
of realistic model in the sort of popular discussion of population,
that it's all just been assumptions about how things are
going to stabilize.

Speaker 9 (20:40):
I think there has been a lot of thinking that
because the population size is growing, it's going to continue growing,
even though there have been signs all along that that
probably wasn't going to be the case. So all the
way back in nineteen eighty, a long time ago, as
we've already discussed on this one, and five people already

(21:01):
lived in a country where the birth rate was below two.
You know, in the nineteen seventies, Europe passed below to Japan,
passed below to Cuba, Australia, Canada passed below too. In
the nineteen seventies, and so not only have birth rates
been falling for not just decades, but centuries. It's long
been the case that we could have seen this coming.

(21:24):
But I think because rapid exponential population growth due to
low mortality was so new on the historical scene that
got everybody's attention, and so it just wasn't that many
that thought through that if then, if the world's average
birth rate falls below two, then what's going to happen next?
And the evidence pointing towards that being the likely future.

Speaker 2 (21:45):
And you mentioned earlier that birth rates vary a lot
from country to countries, South Korea versus other places, And
you know, I've heard anecdotally about subpopulations that have very
high birth rates. I remember my wife in grad school
learning about some population where they have like seven eight
children on average. What do we know about the sort
of variation among subpopulations? Are we going to see the

(22:08):
global population decline but some populations grow very rapidly to compensate.

Speaker 5 (22:12):
What's sort of interesting, and I think flying under the
radar in the popular discourse about this is that really
almost every region on Earth has either low fertility or
falling fertility. So it's really easy to think that this
is a phenomenon that's like special to Southeast the rich
economies of Southeast Asia, or maybe to Europe or the US.

(22:35):
But you know, we're here at Texas, and the birth
rate in Mexico, just south of the border is lower
than the birth rate in Texas. The fertility rate in
Latin America as a whole is something like one point eight,
which is below the replacement rate. Let's see. So the
three largest countries in the world are India, China, and

(22:55):
the United States, and all three countries have birth rates
below replacement and those are places that are very different.
They're different socially, they're different economically, they range. You know,
India's a developing country, China's middle income country. The United
States is an advanced economy. But basically everywhere in the
world we have low birth rates. And the exceptions to
that places like subs Haer in Africa. Birth rates are

(23:17):
still high. So it's still something like four kids per
two adults, but that number has also been falling over
the last fifty years, and demographers tend to project that
will continue to fall into the future as subs Haer
in Africa continues its development in terms of rising incomes,
rising opportunities, rising education.

Speaker 1 (23:35):
So let's take a break and when we get back,
we'll talk about what we know about why birth rates
fall and how good we are at predicting this stuff.

(24:03):
And we're back.

Speaker 7 (24:04):
Mike.

Speaker 1 (24:04):
At the end of the last segment, you were talking
about how birth rates in the Sahara region have gone
from four to Are they dropping from four or did
they go from higher than four to four?

Speaker 5 (24:15):
They've gone from something like six in the middle of
the twentieth century to something like four today.

Speaker 1 (24:21):
So how good are we at predicting this kind of
stuff in like a ten year frame for example?

Speaker 5 (24:27):
So in a ten year frame, professional demographers are good
at predicting population trajectories. The reason that demographers are pretty
good at predicting population sizes over a course like ten
years is that the population just has a lot of
inertia in it, so no matter what happens to they
were sticking too much on calculus here. But a fertility
rate is a flow and population is a stock, and

(24:49):
so you can change the flow as much as you
want instantaneously and it's going to have no immediate effect
on the stock. So in terms of predicting the population tomorrow.
I can pred debt very well, even though I don't
know how many babies will be born today, because most
of that prediction is built up in the stock of
people who are already alive. We know how people age

(25:11):
and die in their later years. We can predict that
with pretty good statistical accuracy. And so the uncertainty is
really about fertility and changes, and fertility actually take a
long time to play out into changes in population size. Now,
how good is anyone predicting whether fertility rates will stay low,
not just in the next decade, but in the next

(25:32):
half century, the next century. I think we should be
pretty clear that nobody knows for sure. But what we're
seeing around the world is a convergent pattern of low
fertility fertility below too. And history is not a guarantee
of future performance. Is That's what they say in stock
market predicting. But if we look around, we shouldn't ignore history.

(25:53):
And if we look around the world at all of
the countries where over a full childbearing lifetime fertility rates
have ever fall in below one point nine, there's twenty
six countries in that category. In none of those have
lifetime fertility rates meaning over the course of women's entire
life ever risen above two again, So that zero and

(26:13):
twenty six record isn't a guarantee of what will happen,
but it would be something that we would do well
to take seriously as a risk for the future.

Speaker 2 (26:21):
So I want to understand what we know about why
this is happening, and then also talk in a minute
about things people have tried and why that might or
might not work. But what do we know about the
overall trends that are causing this.

Speaker 9 (26:35):
So surprisingly less than you might think. You know, everybody
has a theory of why birth rates are low and falling,
but everybody's theories are different, and none of them really
captured the bigness of falling birth rates. And by bigness,
I mean we've talked about how it's something that's been
going on not just for years or decades, but for centuries.

(26:55):
And also that's happening in societies that are very different
from one another around the world.

Speaker 2 (27:00):
And so we can't blame it all on Joe Biden,
for example.

Speaker 9 (27:03):
You can't blame it all on Joe Biden. You can't
blame it all on any one thing. There's going to
be no silver bull exc So you hear people you know,
depending on as you say, there are sort of preconceptions
thinking about well, maybe it's about capitalism or the free
market or neoliberalism that's causing the problem. Or maybe somebody
might say it's about feminism or the retreat for marriage

(27:25):
or the decline of religion that's causing the problem. But whatever,
whatever your theory is, you can find an exception. So
for me, I learn a lot by thinking about India,
which is the country that I study in my research
and where I work. And so India is now not
only the world's most populous country, but the world's most
populous below replacement country. It's below too also, even though

(27:46):
India was the place in the middle of the twentieth
century that was the center of these overpopulation fears. And
what makes India so interesting is that it's a society
where religion continues to be important and in almost everybody's lives,
not just on a piece of paper, but actually something
that's part of their practices. Almost everybody gets married and

(28:08):
at young ages. Almost everybody gets married at young ages
and starts having kids at young ages. And here's what's
particularly striking is that female labor force participation in India
is still pretty low in international comparison, So in a
place like the US or Europe, there's an important story
about conflicts between career and family being part of why

(28:30):
people aren't having so many children. In fact, that's the
title of Claudia Golden's books. She's a Nobel Prize winny
economist's career and family, and this is very important in
many people's lives. But even that's not the explanation that
works everywhere, because it couldn't be what's going on in
India because so many of the women aren't working in
the paid labor force but still having below replacement birth rates,
and so no theory is right or applicable everywhere. And

(28:54):
so part of what's so striking is that, yes, there's
variability across countries, but that very really is shrinking. As
as birth rates fall everywhere, countries are becoming more similar
in this way, and so what we're seeing is a
convergent outcome, and that's part of what makes us think
that depopulation is so likely.

Speaker 1 (29:13):
So Mike kind of already addressed this, but while I
was reading the book, this was a question that kind
of kept going through my mind. So I want to
sort of bottom line this. So we don't understand why
birth rates are falling, So we don't know for sure
that things won't change when we hit a population size
of six billion, for example, But we have really good
data on trends which suggests we should be concerned about this.

(29:35):
Would that be a fair way of sort of summarizing
the argument.

Speaker 5 (29:38):
Yeah, And I think we could say more too. I
think we can sort of do a little bit of
introspection here. Sometimes we can too quickly jump to the
idea that, well, this is like an unsustainable trend. You know,
birth rates can't keep falling. I mean, the first thing
to say there is that birth rates wouldn't need to
keep falling, whether they're already low. They we just have
to stay low. And then the question is, couldn't it

(29:59):
be the case that people could continue to choose to
have the sort of families that they do now. I mean,
in a world that was shrinking, that fell to six
billion or four billion, I think it's quite plausible that
if nothing else in society changed, people could look around
and think. You know, lots of people thinking that two
kids as the right number for them. Some people thinking one,

(30:19):
some people thinking zero, some people thinking three or more.
I think people could continue to make those sort of
choices even as the population was falling. Sometimes people think
that there's going to be some natural rebound to two,
that two is some sort of special number when it
comes to fertility, and two might be the number that
a lot of people choose. But two is not a

(30:39):
special number in terms of a population average. We've never
had a population average in any population any time that
just held exactly at two. When birth rates fall, they
fall right across two, and they don't. There's no like
a magnetic force pulling them back up to two. So
I think there's lots of reasons to think that low
fertility could continue even in the face of a flawing

(30:59):
global population.

Speaker 2 (31:00):
I think you're bumping up on something really interesting there,
which is implicitly doing differential equations. You know, you're telling
us that people don't respond to the density of people
around them. It's not like families get together and they're like, hmm,
there's lots of kids in the kindergarten, Let's have fewer kids.
Or while kindergartens seem empty, let's have more kids. That's
not sensitive to the population itself, right.

Speaker 9 (31:21):
And it's more than that, it's that it might not
even seem that different. And so you know, in Texas
right now, the average is one point eight. What if
the average instead were two point one. You know, that
would make the difference for the world as a whole
between depopulating and growing. But I don't think life would
seem very different living in a society with an average

(31:43):
one point eight from living in a society with an
average of two point one. When you're you know, jogging
around the park or going to the store, it would
feel pretty similar. And I think, you know, back to
the question of how did this all slip under everybody's
radar and how did we get on the path of
depopulation with that everybody noticing? I think I think part
of it is because, at least in the United States,
where we were right around this two level for a

(32:05):
long time, one point it's just not going to feel
that different from two point two, but it's going to
have very different consequences for the long term future.

Speaker 2 (32:13):
And the story we're sort of getting to is that
birth rates and rates of production of children somehow depends
on a lot of complicated factors that it's not always
obvious to dig out. And it reminds me this story
I remember from my wife being in graduate school shit
a friend who was working to study this population of
hutter Rights, a small religious community in the Midwest, and

(32:35):
they have like an enormous fertility rate, like huge numbers
of children. And I remember these researchers studying like why
is it, why are they so fertile? And eventually the
answer was they just have sex every day and why
they have so many kids. And so it's not like,
you know, we want to populate the earth, or kindergartens
are too empty. It's just like a product of lots

(32:55):
of choices people are making about.

Speaker 1 (32:57):
Their days, but their numbers are going down too.

Speaker 5 (33:00):
We talk a bit in the book, not about the
hutter rates, but about like the Pennsylvania Dutch, the Amish,
and we talk about it because I think a sort
of a certain kind of math inclined person would hear
these arguments and think, huh, well, it's one thing to
say that many populations have birth rates that would lead
to decline, but there are these subcultures like the Amish

(33:20):
that just have tons of kids. Right, So even if
we're not having a lot of kids in the rest
of America. The Amish are having a lot of kids,
and you could do a sort of extrapolation to think, well,
if the Amish keep having more and more kids, they're
going to build up to be a larger and larger
fraction of the population. And you know, so you know,
we look this up and the recent population growth rates

(33:41):
of the Amish or something like four percent a year,
and if you just extrapolate that naively, then you know,
in two hundred years there's going to be a billion
Amish in the world. But we don't think that argument
makes an awful lot of sense for a couple of reasons.
One is that sort of high fertility enclaves, whether it's
the Amish or any other, their fertility is also going down,

(34:03):
like Kelly alluded to. So, you know, maybe last century
the Amish we're having eight kids per two adults. Today
the estimates put it as something like five or five
and a half kids per two adults. It's hard to know.
There's not a census of the Amish the way that
there's like a census of Texas. So reason one is
that even among high fertility subcultures, what counts as high

(34:24):
fertility is changing over time, and you know, Sunday high
fertility might be in two kids instead of one, rather
than five kids instead of three. The other reason that
we shouldn't count on the Amish outnumbering grains of sand
on the beach is that people don't always adopt the
cultural practices of their parents. We see cultural change all

(34:45):
over the world. South America is changing from being more
Catholic to becoming more Protestant over time, just as one example.
But you know, in our own lives, I think we've
all had the experience of being teenagers and projecting one
cultural practice or another of our parents. These these links
that connect generations aren't perfect. And you really have to
push this idea of cultural heritability pretty far to think

(35:07):
that even as the Pennsylvania Dutch ran out of Pennsylvania farmland,
because you know, they're spilling across continents, because there's just
so many of them, that somehow these cultural practices and
preferences are going to be inherited one for one from
parent to child.

Speaker 1 (35:23):
I think some of that cultural stuff is at play
with the Hutter rates. Hutter rates are communal. So my
husband and I spent a lot of time reading about
them when we were trying to decide if communes would
be a good model for early space settlements, and so
we became sort of experts in hutter rates, and they
were also lamenting their declining birth rates.

Speaker 2 (35:42):
I keep waiting for somebody to make a weird al
joke here. Nobody's going to talk about how we're not
going to be living in the future Amish paradise.

Speaker 1 (35:48):
Now we missed that cultural touchstone. Let's talk a little
bit about why depopulation could be bad. So, you know,
as an ecologist, the idea that we might have four
billion people, like, I don't want there to be zero people.
I like people, and I don't want any people to die.
But if people are choosing to not have as many
babies and we end up with something like four billion,

(36:10):
it doesn't sound so bad to me initially to have
fewer people that we invest more in. But you all
make a pretty good argument about more people being better
for a lot of reasons. So let's hear about why
we don't want billions of people fewer on this planet.

Speaker 9 (36:23):
Well, first, I want to hold on that four billion
thing for a second, because I think it's important if
somebody's listening to this and they're thinking, yeah, let's have
some depopulation. And what I want is a future where
the world stabilizes at some number like four billion or
three billion or two billion. Then that sort of future

(36:45):
would fundamentally require the same thing we're talking about here,
which is an increase someday in birth rates. Right, the
population is not just going to suddenly hang and hold
still at eight billion or ten billion, and it's not
just going to suddenly hang and hold still at four
billion either unless birth rates go back up. So in
our book, after the spike, what we're considering is would

(37:07):
it be better to have a future of depopulation generation
after generation or would it be better instead to have
a future of stabilization. And not to hide the ball,
we make the case for a future of stabilization. Now
we don't say where. That's beyond what anyone could know
given the science we have. But let's take four billion.
For the world's population to ever stabilize someday at four billion,

(37:29):
that means after a period of depopulation, birth rates around
the world are going to have to go back up
to to and stay there.

Speaker 2 (37:36):
And I just want to bottom line that to make
sure people caught that because you're arguing that if birth
rates stay below replacement, we won't just go from eight
billion to four billion, we'll go to two billion and
one billion and a half a billion, and you just
keep going.

Speaker 5 (37:48):
Down, right.

Speaker 9 (37:49):
It's you know, when your rocket ship gets to the
planet that you want to be on, how do you
slow down and stop right? When the global population gets
to the size that you want to stabilize that four
billion or three billion or whatever, if you want to
stay there, then just like at any other size, birth rate,
you have to be an average of two. So this
is my conciliatory message that we're on the same team here.

(38:11):
If you want the size of the population to stabilize somewhere,
and we face the same question of how would we
ever get back to a birth rate and an average
around two. Okay, Now, another question, and it's the one
that you asked, which is.

Speaker 5 (38:26):
Why would we want that?

Speaker 9 (38:27):
Why would we want the size of the population to
stabilize or to avoid depopulation generation after generation? And here's
one reason why we think that depopulation matters and that
we should want to avoid it, because we're all made
better off by sharing the world with more other people,
Other people alive alongside us, other people who were live

(38:49):
before us. Other people make the discoveries and have the
ideas that improve our lives. And other people are where
science and knowledge comes from.

Speaker 1 (38:57):
I like people too.

Speaker 2 (39:00):
People are awesome.

Speaker 5 (39:01):
We can drill down on that too. I mean, why
are lives better now than a couple centuries ago?

Speaker 7 (39:07):
You know?

Speaker 5 (39:08):
Why do we all have shoes on our feet and
glasses to correct our vision, plenty to eat, climate controlled work, environment,
shorter workdays, a library of literature AI in our pocket?
You know, social safety net systems to protect the elderly
and disabled. Why our living standards so much higher today
than not all that long ago. It's the same sun overhead,

(39:29):
it's the same wind blowing, it's the same dirt underneath
our feet. But knowledge is the difference. We know better
what to do with these things. We know how to
extract the minerals from the rocks and make glass and
solar panels and computer chips. We know how to farm
more efficiently to grow more food, more calories per acre
of that dirt, and we know how to do that
with less human labor. We know how to make soap

(39:49):
to keep us from getting infections. We know how to
make antibiotic pills to treat infections, and we have a
germ theory of disease so that we know what an
infection is. And we know all of these things because
of people that came before us. We know better how
to organize a kindergarten or a cancer drug trial, or
a parliamentary democracy. These these things ideas, discoveries, process improvements, innovations.

(40:14):
They are why we all on this call of listening
to this podcast get to expect more out of life
and better things out of life than people did not
all that long ago. This notion is something that economist
Paul Romer won a Nobel Prize for in twenty eighteen,
and his realization that he sort of formalized in the
language of economic math was that an idea isn't scarce

(40:39):
in the same way a parcel of land or a
physical object like a hammer is scarce. Instead, an idea
can be reused and shared endlessly. You know, we've been
talking about differential equations. I took differential equations as an
undergraduate engineering major. Maybe Kelly or Daniel you had the
same textbook as I did, But what I read the

(40:59):
words out of that textbook. It didn't cause the words
to disappear from your copy of the textbook. Right, We
get to reuse these ideas over and over again. And
so once Newton or Leibniz invents calculus, or maybe if
they didn't live, somebody else would have, then we all
get to benefit from that over and over and over again.
So ideas and scientific knowledge are a sort of special

(41:22):
resource that never gets depleted no matter how much it's used.
And that's sort of one of the core reasons why
sharing the world with a lot of other people. We're
getting to live at a time after a large population
has already existed. It's just a huge benefit to us.

Speaker 2 (41:38):
And it's more than just expanding the population and creating
new innovations, right, it's about maintaining our quality of life.
We need a certain number of people to keep making
t shirts and pencils and teaching our children like the world.
Our infrastructure can't survive on a tiny population. But it
makes me wonder if we're going to do a ridiculous
extrapolation tell us about sort of the numbers of people

(41:59):
we expect to have on Earth. If birth rates don't change,
how many people we have on Earth in ten years,
fifty years, one thousand years, extrapolate all the way out
to you know, twenty five thousand years. Are we going
to end up with like twenty people on the planet.

Speaker 9 (42:13):
Okay, we don't know, right, we don't have a crystal ball,
but we can make if then assumptions, right, you know,
if the birth rates end up like this, then we
can say something about how the future would evolve. And
so one easy and plausible case is to imagine the
worldwide average birth rate of one point five, which is
what it is right now in Europe, you know, a

(42:34):
little bit less than in the US, and a little
bit more than in Canada.

Speaker 5 (42:38):
So one point five.

Speaker 9 (42:39):
That's the next generation being twenty five percent smaller, the
next generation after that being twenty five percent smaller.

Speaker 5 (42:46):
Again.

Speaker 9 (42:46):
So if the world were like that, then every decade
we would see the size of the world population fall
by ten percent, and every century the size of the
world population would fall by two thirds, and that cumulative
exponential decay would continue and we could get quite small
in just a few hundred years. If instead of it

(43:06):
being one point five, it were an average of one
like in China today, then you can see the next
generation is going to be half the size. The generation
after that, the grandchildren's generation is going to be a
quarter the size, and so the fall could be very fast. Now,
how does all of that play out? How does that,
you know, cash out in something big breaking or something
breaking down, or not having the discoveries we need, or

(43:29):
even the librarians to staff the libraries that we can
maintain the knowledge we have. That's hard to know, but
we can learn something about it by thinking about sort
of comparing more populated places like cities and less populated
rural places. You need enough other people around who want
and need the same sorts of things that you want

(43:51):
and need in order for those things to exist to
be feasible to be provided by a government or a
business or a nonprofit other people wanting and need. What
you want is how you get in. That's true if
what you want is well functioning public transportation, because a
network of trains and buses can't operate without enough riders.
It's true if what you want is a green energy

(44:13):
infrastructure built on the work of scientists and engineers and implementers.
And it's true for all of us as a whole.
If what you need is a vaccine for a novel virus,
or a cure for a rare disease. It's the sorts
of things that only the niche medical specialization of a
big world could produce. And so as there are fewer
and fewer of us, we're not going to be able

(44:35):
to provide those sorts of discoveries, products, innovation, creation that
are only possible with other people. So other people may
sometimes be another person may sometimes be your competition, but
other people there being other people over the long run,
or why things like this can exist and there resource
of abundance.

Speaker 1 (44:56):
Let's take a break, and when we get back, we'll
talk about some let's say, less than compassionate methods that
have been used in the past to try to improve
birth rates, and what are some more ethical options we
could consider in the future for improving birth rates. And

(45:28):
we're back and we are talking about how the average
birth rate globally has fallen below too and the implications
of that. So when I think about ways for trying
to improve birth rates, the first thing that come to
mind are some authoritarian governments who have tried to control
birth rates in ways that I'm not super comfortable with.
To put it lightly, so let's review some methods that

(45:51):
have not worked when countries have tried to improve their
birth rates in the past. What do we know does
not work well?

Speaker 5 (45:57):
All of them? All of them.

Speaker 9 (46:00):
There isn't an example of, you know, government coercion, whether
trying to coerce higher birth rates or trying to coerse
lower birth rates, you know, resulting in the sort of lasting,
big picture, sustainable change to birth rates that could knock
the population off of a path of depopulation and onto

(46:23):
a path of stabilization. I mean, I want to take
a step backwards here. You know, we're making the case
that a stabilized future population would be better than global depopulation.
We also think that a stabilized population is compatible with
commitments to environmental stewardship, to reproductive freedom, and to progressive

(46:44):
priorities more broadly, and we want other people to think so,
to be a part of this conversation. So we don't
want anyone to misunderstand that if somebody chooses to have
no children or few children, that's not for anyone else
to say whether they're making a mistake. And that's a
question of an f starting point. But it might still
be that all of us together are making a mistake

(47:05):
when we make it hard for people to choose larger
families and choose to have children. So you can talk
about this and talk about whether stabilization is the future
we want without it, you know, necessarily invoking the idea
that anyone should be coercing anybody else. Now, that said,
it's an important and reasonable thing to worry about, because

(47:25):
there have been examples where governments have tried to compel
people to have kids they don't want to have, or
to compel people not to have kids. So, you know,
the classic example that people think about is China's one
child policy, where the government of China made it illegal
and with harsh and coursive implementation to have what they

(47:48):
consider to be too many children. And sure enough, if
you look at the birth rate in China over this
time period, it fell. However, that doesn't turn out to
be evidence that the one policy is why birth rates
in China fell. And the surprising fact is that if
you take the birth rate in China over time, so

(48:09):
make a plot where you know you're looking at the
birth rate in nineteen eighty the birth rate nineteen eighty five,
the birth rate in nineteen ninety. What you see is
the birth rate in China fell overtime while the one
child policy was in effect. But if you also look
at what happened to birth rates over time in any
other middle income developing country that was also undergoing the
same sort of increase in living standards, increase in education,

(48:32):
specifically increase in female education, you see birth rates falling
in basically the same parallel way that that was happening
all around the world in countries about that sort of
level of socioeconomic development. And so what that tells us
is that it probably wasn't the one child policy that
was responsible for the big picture decline in birth rates
in China. It's not to say that China would have

(48:53):
ended up in the exact same place without the one
child policy, but somewhere pretty similar. And it's certainly not
to say that one child policy didn't do a lot
of harm to people's lives in China. But the birth
rate is probably where it would have been otherwise.

Speaker 1 (49:07):
And wasn't there. I can't believe that. I'm forgetting the
name of the country and the leader was it child Chescu.
Somebody tried to increase birth rates by making birth control
unavailable or something like that. Correct my historical inaccuracies, please
and tell us that story.

Speaker 5 (49:21):
No, that's you are correct. So this was Romania, This
was nineteen sixty six or sixty seven, Chescu. He implemented
decrease seven seventy. And what decrease seven to seventy said
was that birth control was no longer going to be
available or legal, that abortion was going to be illegal.
And just to put this in context, in Romania, prior

(49:45):
to that time, abortion was more freely available than it's
ever been for like the whole of the United States.
So this was a big change in Romania, and that
big change overnight did cause birth rates to rise overnight.
So you know, you pulled the rugout from people, you
change what's available to them, and birth rates did climb

(50:07):
between nineteen sixty six and nineteen sixty seven. I think
they something like almost doubled.

Speaker 7 (50:11):
Wow.

Speaker 5 (50:12):
But in the years that followed, birth rates started tacking
back down, and you know, within something like a decade,
they've fallen two thirds the way back from where they
started prior to the policy, as people made other plans
and built their family planning around the new coercive regime,
so that policy did a lot of harm to people,

(50:34):
and you know, just a lot of harm. I mean,
women died, pregnancy became very unsafe. So it was awful,
but it was awful without achieving the goal of boosting
birth rates super high. And you know, Chescu was overthrown,
was lined up against the wall and shot. And so
if your formula, and I know this is not anyone

(50:56):
on this cause formula, but if it's anybody's formula to
try to bring birth rates up by you know, a
dictator coursing women to have children they don't want, that's
not a sustainable option for anybody, including that dictator.

Speaker 2 (51:09):
So you want policymakers in the audience to hear that
as a cautionary tale.

Speaker 1 (51:14):
It's a good message. So in either direction trying to
push numbers up or push numbers down. We don't have
good evidence that it works, and it's incredibly unethical the
way it's been done.

Speaker 5 (51:25):
Yeah, it's I think we have I say, even something
a little bit stronger. We have good evidence that it
doesn't work.

Speaker 2 (51:30):
What about other things like trying to provide more childcare
or making college cheaper, or more family planning. Aren't there
ethical ways we can make it easier for people to
have more kids.

Speaker 5 (51:42):
There are lots of ethical things that we can try
and that countries have tried. Unfortunately, the track record there
isn't as great as one would hope it would be.
So I think we're still still a long way to
go to figure out what might work, you know, on
this question of making childcare more affordable, more available. You know,
if you look to Scandinavian countries, for example, places where

(52:04):
college tuition is free, where there's universal health care, where
there's childcare that's not only heavily subsidized or free for
you know, pre K childcare, but it's also provided like
it's available. I don't know what your experiences are, but
my experience as a parent is like it's just hard
sometimes to organize childcare for when work is on but

(52:25):
school is out or you know, summertime. It's a patchwork
of things. But even in places where childcare is better organized, free,
where tuition is free, where healthcare is more available or
free provided socially by the government, these aren't places with
high birth rates. And so yes, I think there are
things that there's plenty left still to try in the

(52:47):
toolkit of what like free liberal societies can do to
make life better and easier for parents. But I don't
think anybody, not governments, not social scientists, have figured out
that what that special sauce is.

Speaker 9 (52:59):
Yet I want to sort of say that maybe that's
not so surprising. I mean, think about, you know, the
sort of policies that we hear of, you know, a
few thousand dollars baby bonus or something like that. Right,
you know, let's do a thought experiment. Would you have
agreed to marry somebody other than the person who you
married for about five thousand dollars? I don't think very

(53:22):
many people are going to say yes to that, right.

Speaker 2 (53:24):
Our spouse is listening to the podcast, so that question, well.

Speaker 9 (53:28):
Okay, so it's not a fair task or anonymize. I
didn't do my research procedures, right, But I think you know,
these are people's biggest decisions forming their family. What's their
life story about? What autobiography am I writing?

Speaker 5 (53:41):
Right?

Speaker 9 (53:41):
You know, a few thousand dollars will help a lot.
And you know, if you ask me or yes, Mike
will say that society should do more to help parents,
must do more to help parents, right, But when we
say do more, we're meaning something a lot bigger, and
it just shouldn't be a surprise. If we don't think
that a few thousand dollars is going to change who
you're going to marry, it's probably not going to change

(54:03):
your biggest picture decisions about how to form your family
and form your own life story in other ways too,
And so yes, by all means, let's support parents, support families.
Let's do that, but let's not be surprised when that doesn't,
you know, shift us from the path to depopulation the
path is stabilization.

Speaker 1 (54:23):
I was listening to Left, Right and Center the other
day and one of the hosts, Sarah Iger, was saying that,
you know, one of the reasons population is going down
globally is that when women have more reproductive choice and
more options in life, they choose to have fewer kids.
And one of the things that I love that you
all addressed directly in your book was that increases in
population size, would you know, in the absence of artificial wombs,

(54:47):
have to come from women having more babies, which has
a health impact, a career impact, et cetera. So one
my question is is it true that when women have
more choice, they have fewer children, and that's the mechanism.
It sounds like maybe we don't understand that mechanism as well,
based on our conversation we've had, and what do you
propose as the method for having more babies in a

(55:08):
way to do it that sort of distributes this responsibility
more evenly.

Speaker 9 (55:13):
I think that we all have a shared interest in
their being future generations, and so that we all need
to be pitching in to making there be future generations
and sharing and lifting those burdens off of one another.
And I think it's no surprise that in a history
where we have long put a lot of that burden

(55:36):
on a subset of the population, I mean mothers in particular,
that we have people saying no, thank you. But because
that's been the past, that doesn't necessarily mean that that
has to be the future. I mean, sometimes we hear
people talking about these conversations about low birth rates, and
they act like there's a choice we have to make.
Either we can have regressive gender politics that ask more

(55:59):
of women, or we can have global depopulation. I think
people both on the left and the right start these
conversations with the presumption that if we're going to stabilize
the population, the extra burden has to fall on to women,
and I don't think that's right. I don't think that
we should start by asking more for mothers. I think
the place to start, or a place to start, is

(56:20):
by asking more from fathers. Males can't get pregnant, that's right,
But it takes more than nine months to make a
new person. It takes decades to raise a child into
a new adult. And that means there's plenty of time
and plenty to do for men to even things out.
Dads can get up at three am to sue the
crying baby. They can cook even though they're tired. They
can process the laundry and pack the snacks and figure

(56:43):
out about the childcare when school is out, and drive
to swim lessons and do so much. They can accept
the work and the responsibility and being the person who's
on call on sick days and summer days, and they
can do that for years and years and years and years.
You know, I think this is it sounds nice. I
mean it's more than just hopeful rhetoric. I think it's

(57:03):
a challenge, and we shouldn't consider there to be any
sort of guarantee that this is what's going to happen.
But the future of birth rates is going to be chosen.
Whether or not we depopulate and whether and where we
stabilize is are going to come down to the choices
that people and especially women make for their lives. That
seems pretty clear. And so if we're going to expect

(57:26):
people to choose parenting, then there's work that we all
need to do to make parenting more attractive, and that
starts with lifting and sharing the burdens that for so
long have only fallen on.

Speaker 2 (57:39):
Some of us.

Speaker 1 (57:40):
I loved reading that part of your book.

Speaker 2 (57:42):
And is this why you've written a popular book instead
of like making this argument to policymakers and within academia.
Are you're writing this to the general public to make
people aware of this coming issue.

Speaker 9 (57:53):
Well there's that and the differential equations, but no.

Speaker 2 (57:58):
That's really your goal in the end, right, This is
really just a math lesson This.

Speaker 9 (58:01):
Is a topic that more people should be talking about,
not just you know, more numbers, but a broader set
of people. We're at the very beginning of facing up
to this challenge. Most people haven't yet come to the
terms of the magnitude of what we're facing. But you know,
we wouldn't have written this book calling to avoid depopulation
if we didn't think it were possible for humanity to

(58:25):
change course. Depopulation is the path that we're on, but
it's not the inevitable future. People ask us, so, what's
your policy recommendation, what legislation would you write? And I
think jumping to a policy solution at this point is
probably the wrong move. This isn't something that's going to
turn around in one presidential term or because of one
set of legislative considerations for parents, or you know, a

(58:47):
new bill about print to leave. I think we're facing
something big, and the first step is many more people
sharing a belief that we should want something to change.
That's necess Harry precursor. If you're already convinced and you're
asking what to do next, I don't think it's advocate
for a particular piece of legislation. It's invite more people

(59:09):
into the conversation and convince your friends and family and
classmates and colleagues that people are fundamentally good for another
and that depopulation is not going to get us off
the hook for challenges like climate change and our environmental
problems that we face. Start a conversation about what could

(59:29):
be good about a future in which more people feel
like they're able to and support it to choosee parenting.
That sort of re orientation to thinking that stabilization might
be a good future has got to be the first step.
And in the meanwhile, there is a lot of social
science to do that we should be building out to
better understand what might work, so that once we're able

(59:49):
to build the social and the political support for a
stabilized future, will know what to do. But there are
a lot of minds to change first.

Speaker 2 (59:57):
Can I end us on an alien's question?

Speaker 1 (59:58):
Of course, it wouldn't be a DECA episode about it.

Speaker 2 (01:00:02):
So the fact that we see this trend across so
many different communities in so many different circumstances makes me wonder,
naturally if this is something that exists in I don't know,
all intelligent technological civilizations in the galaxy. And do you
think maybe what you've done here is stumble on the
solution to the Fermi paradox.

Speaker 5 (01:00:18):
I'm so glad you asked that. Wait, wait, wait, wait,
we need to we need to stop just for a moment.
You've really made Dean's day. He wants to put the
Fermi paradox in the book. Don't we ended up putting
the Fermi paradox in.

Speaker 2 (01:00:29):
The book, big mistake.

Speaker 7 (01:00:31):
We cut it.

Speaker 9 (01:00:32):
There was a cutting room for But I was interviewed
on a podcast from someone at SETI and I brought
this up and he was just it was almost like like,
how how could I say something so silly and smirch
the podcast? But yeah, I mean, I think it makes
a lot of sense that, you know, individuals have to
sacrifice to make the next generation. There are shared public

(01:00:55):
benefits of there being a next generation. We're gonna you're
gonna learn how to control your birth rates, and so
I do think that this sort of dilemma is probably
a common one. Now, I am just a humble demographer
of utra British India.

Speaker 5 (01:01:13):
I don't you know.

Speaker 9 (01:01:13):
I can't speak to the larger questions.

Speaker 1 (01:01:16):
But Dean is glowing right now. Everyone, He's very excited
to be talked about this. We love it all right,
Dean and Mike, thank you so much for being on
the show. This was fascinating and anybody who wants to
learn more should go grab the book after the spike.

Speaker 5 (01:01:30):
Thanks very much, guys, Thank you so much.

Speaker 7 (01:01:32):
Thank you.

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