Astronomers tell us that when we look to the night sky,
we're actually looking back in time.
Light from those faraway stars takes so long to reach our eyes
here on Earth,
that by the time we wish upon a particular star,
it may no longer even exist.
I'm here to tell you the population of Earth
is a lot like those stars.
In parts of the globe,
the human population is already, or will soon be, shrinking.
I know what you're thinking.
And yes, total population is still growing from eight billion today
to a peak of probably nine or 10 billion.
But when we track total increase,
we're looking at the star that seems to be shining brightly,
but in actuality has already imploded.
And that’s because there’s a difference between what’s happening on the surface --
which is obvious total growth -- and the tectonic forces beneath.
Since the 1960s, world population has more than doubled,
but the growth rate has been falling the entire time.
We're witnessing the most fundamental shift to take place
in modern human history.
The shift towards pervasive and permanent low fertility,
population aging and eventual depopulation.
Fertility is down everywhere,
just at different rates in different places.
If fertility stays the same as it is today, just hold still,
by the end of this century,
China's population will be less than half of its current size.
It's a loss of 800 million people.
South Korea's will be down by 63 percent,
Poland's and Japan's by half,
Italy's and Thailand's by 44 percent,
Eastern Europe by 40 percent.
Even greater number of countries are already aging.
Again, just 20 years ago,
if we'd lined up everyone in Japan or Italy or Germany
from the youngest person to the oldest
and we ask that person in the middle their age,
they would have been 40 years old.
Today, the populations of Thailand, Kuwait and Cuba are just as old,
with Chile, Iran and Vietnam close behind.
And even India,
as it seems to be this bright star,
assuming the throne as world's most populous country,
has below-replacement fertility.
The number of young people entering into India's workforce
has already peaked.
People are the foundation of everything in a society.
We're the workers and the voters
and the soldiers and the caregivers.
So how many of us there are and who we are, that matters.
We're on track for there to be more people over age 60
than under the age of 14 by the middle of this century.
That radical shift in modern human society
presents us with a world of possibilities.
Our demography is our destiny, yes,
but how we react to that demography is not preordained.
What possible worlds might we create
if we thoughtfully plan for an older,
smaller population?
In one possible world,
we put our heads in the sand
and keep going about our business as usual.
We have seen most societies react like they're living in this world
and throw money at people to have more babies.
But it doesn't work.
South Korea has spent 210 billion dollars
over the last 16 years trying to raise fertility
and they keep hitting record lows, under one child per woman on average.
In this status quo world,
we keep the same economic models that assume infinite population growth
and amass more debt to pay for our public spending.
Our social safety nets stay the same,
which, those rely on more inputs from workers
than withdrawals from retirees.
That's what we call a pay-as-you-go system.
Western Europe is already struggling to keep these systems afloat
because in many of those countries
there are only two workers for every retiree.
You can see how top heavy the population's age structure is here
and how in the next few years it will grow even more so that way.
In a status quo world,
the world's most powerful countries continue to increase military spending
and try to project power beyond their borders,
even as their national budgets strain
and the recruiting pool for soldiers shrinks.
Hello, Russia, China, and maybe even the United States.
So what results from failing to adapt and clinging to the status quo?
Systems overload and break.
We have higher labor costs which lead to inflation
and that just makes it even more expensive to have children.
Social security systems go bankrupt
and we lose the gains we've made in reducing old-age poverty.
But a head in the sand world isn't as bad as a fearful one.
In a fearful world,
the ability to choose how many children to have
and when to have them gets taken away.
Something that's easier in less democratic settings.
And not good news here either.
Twenty years ago, almost all of our aging countries were democracies.
Now, a quarter of them,
those with median ages of 35 or higher, aren't free.
And I know we see this idea of coercion in science fiction,
but it's not just science fiction.
In 1965, when Nicolae Ceaușescu took the helm in Romania
and he wanted more Romanian babies,
he forced it to happen through invasive measures.
Fertility temporarily spiked,
but not without dire consequences for women and for those children,
many of whom were abandoned to orphanages.
In a fearful world,
immigration becomes more restricted.
There's more hatred and division
as majority groups fear being replaced by people who don't look like them.
There’s less global cooperation as aging, shrinking countries,
they lose the willingness
and ability to think about causes outside their borders and fund those.
We can't come together on pandemics or climate change
or other transboundary issues.
Does any of this sound familiar?
I actually don't think we're fully in this world yet,
even if way too much of this hits close to home.
But I can imagine how we might get there
if we aren't proactive to shape the world we want.
And what kind of world would we want?
Well, in a resilient world,
we compete to attract talent from across the globe
and set aside our nationalist tendencies.
A shrinking world is in our future,
but obviously some places are much closer than others.
In the Democratic Republic of the Congo, Ethiopia, Nigeria, Tanzania,
fertility is still high enough that each generation is twice the size
of the one before it.
Those young and growing populations can be a tremendous resource
for their national economies
if we have investments in human capital and other policies
that can help these countries reap a demographic dividend.
And they can be a resource for the global economy too.
I mean, the US and Canada,
they stand out as still growing despite below replacement fertility in both.
And in fact, Canada had record population growth last year,
96 percent of which was due to immigration.
Theirs aren't the only models for immigration
and there are obvious trade-offs to opening your borders.
But no one said this would be easy.
And speaking of things not being easy, we're going to have to work longer.
Me too. You too.
And that's because in nearly half of economies that the OECD tracks,
fewer than 10 percent of people over the age of 65 still work.
That is not going to fly in a resilient world.
But in a resilient world,
we've rethought what work looks like at older ages,
and we strategically leverage technology to maximize our productivity.
And we can work longer because we're healthier.
In a resilient world,
we finally realize that investing in health
is a much better use of time and resources
than trying to dictate population size.
Similarly, in a resilient world, we've put in place policies,
incentives and technologies
that recognize how we consume is just as important
as how many of us consume.
And the environment is healing.
In a resilient world,
those societies closer to the start of this demographic transition
take advantage of the time to plan and institute sustainable systems
in the face of their demographic change.
This is important
because for the population ages 60 plus
to go from 15 percent of the total to 30 percent,
it'll take Ireland 92 years,
the United Kingdom 89 years,
and Germany 70 years.
For that same demographic shift to happen now,
it'll take India 34 years,
Mexico 32,
Iran 20
and Thailand, only 19.
It's happening faster now.
And we really need to realize this because those countries have to act,
including suites of policies like moving away from informal economies
that increase the risk of poverty in older ages.
You know, there are so many people on the planet right now
just between the ages of 65 and 74,
that altogether they'd be the third most-populous country in the world.
There's far more of them than there are global migrants,
which we don't hear about, right?
And there'll be 800 million of them by the middle of this century.
They're a vast untapped resource in most places in the world right now,
but a well-utilized one in a resilient world
and to mutual benefit.
We should run from a fearful world and get our heads out of the sand.
And we should be able to imagine a much better, more resilient world.
I've always thought that the way we feel about population aging
to a large extent reflects the really negative way
we feel about our individual aging.
And that bias has held us back.
But just as with our own aging, this shift is inevitable.
So what are we going to do about it?
As individuals,
we know that our actions now set us up to live longer, healthier,
more financially secure lives.
Our society's actions set us up
for one of these three worlds to become our reality.
Let's make it a resilient world and reimagine a grayer,
smaller world as a beautiful one.
Thank you.
(Applause)