How many people can Earth support?
This question plagues people.
It keeps people up at night.
Once you realize that we live in this little speck in the middle
of space, nothing gets in, nothing gets out,
it really can weedle in there, you know?
Most studies find that we could have 8 to 16 billion people
on this little planet.
This is referred to as the planet's "carrying capacity."
And eventually, the system is going to break down.
Mathematicians, environmentalists, economists,
they're all working on how we can get more people
to live on this planet.
10 billion is the tippity top.
The tippity top.
How do we get to where we need to be to feed everyone?
Let's kick into it.
[MUSIC PLAYING]
Hey, everyone.
Thank you so much for joining.
Episode four of five starts now.
This week, we're talking about how many people the planet can
realistically support.
People love to throw out different numbers.
You know, if everywhere was built
with the density of Hong Kong, we
could fit trillions of people on our planet.
Which is silly, because those people
would need to eat and drink and excrete waste and probably go
outside once in a while.
If the American diet was adopted by everyone,
on the opposite end here, we could feed maybe
1 and 1/2 billion people.
That's how bad our diet is.
But that's not the whole picture,
because right now, we have 7 and 1/2 billion.
The UN predicts 9.7 billion by 2050 and 11 billion by 2100.
If we can't feed people, then we're
going to have mass famine, food shortages, or who knows.
Are we on the brink?
Experts think not yet.
We learned back in Episode 1 earlier
on that you can save money by cutting meat out of your diet.
You can save $750 a year by becoming a vegetarian fully,
and you can save fractions of that
by cutting meat out of your diet.
It's great.
The United Nations Global Environmental Service
looked at dozens of papers from the last 30 years
and they organized the estimates into this amazing graph
that I've recreated here for you.
And this echoes what I said earlier.
We can support eight to 16 billion.
According to the Harvard University sociobiologist
Edward Wilson, the common limiting factor
is fresh water and the amount of arable land.
If you have 10 billion people with no cattle, not taking
into account the rainfall, nitrogen
cycle, available quantities of phosphorous,
which are all problems when you're growing lots of food
for lots of people, the 3 and 1/2 billion acres
that we use today, the 2 billion tons of grain
annually would be enough to feed 10 billion vegetarians, or 2
and 1/2 billion US omnivores.
So let's be honest.
You're never going to get 100% vegetarian society globally.
It's not going to happen.
If we could do anything, what would we do?
Mathematical biologist Joel Cohen,
in his book How Many People Can Earth Support-- great question,
Joel, I've heard that one-- there are three paradigms.
I love a paradigm.
In the face of a global catastrophe,
one needs a bigger pie, fewer forks, and better manners.
I see what you did there, JC, making the like food jokes.
It's nice.
So one, bigger pie.
In post World War II, the huge issues with food
caused famine all over the globe,
and we were worried we wouldn't make
enough food to feed ourselves.
The American experiment actually did such a good job with that
that Soviet scientists came to see how our farms worked
in this country.
It's amazing.
It was called the farms race.
And I really want to make a whole video just about that.
You can look it up.
It's amazing.
Anyway, Norman Borlaug bred two special wheats.
He took wheat with high yield and he mixed it
with wheat that was short, stocky.
It was called hybrid dwarf wheat.
Well, it lifted people out of famine.
Wheat yields nearly doubled in Pakistan and India just because
of this invention.
And Borlaug won the Nobel Peace Prize in 1970.
Without Norman Borlaug's invention,
we would not be able to feed the 7 and 1/2 billion we feed now.
We need more inventions like that.
Thinking outside the box.
Not just growing crops in regular ways and saying like,
what if we water them more, or what if we add pesticides
to the way we already grow crops?
We need to make super crops and grow them in super ways.
People are working on that, but that's one.
Two, fewer forks.
Ultimately, we live in a fishbowl, in an aquarium.
Earth doesn't get any bigger.
We just use the things that are here over and over again.
Can the Earth keep up with the current population growth?
Of course it can.
We'll just destroy more of it as we continue to live here.
There is a lot of empty space on our planet,
but we can't just keep occupying more of it
until there's none left.
The Worldwatch Institute, a think tank
on global environmental concerns,
says that if you split the world into 100 square meter
blocks, that is, a hectare, that would
be 1.9 blocks per person for food, for absorbing waste,
and to produce all their textiles and cotton and stuff.
That's it though.
And so what we need, according to this,
is fewer forks, i.e. we need people to not overpopulate
the planet.
It would be better for the planet
long term if we get to a replacement rate, says Cohen.
We get to 2.1 children per adult.
That would be a sustainable population.
And I know this is ethically very difficult.
Maybe pay people to have 2.1 kids?
Then they can choose to do what they want.
If you have ideas, share them.
That's tough though.
Fewer forks.
Three, better manners.
In Star Trek, the Vulcans landed,
once Zefram Cochrane warped near the planet,
and showed that we were ready to meet people from other planets,
because we were beginning this journey into the cosmos.
Earth started becoming one planet.
And better manners means exactly that.
We need a global culture that needs
to adapt to how we have to live on this planet.
Humans need to work together, be more
than individuals and warring nations and fighting people.
This is outside the scope of a nerdy science
show like this one, but I'd love to hear your ideas on it.
Cohen says we need all three of these things
in order to survive long term.
He says, to get there, we need to promote access
to contraceptives, develop more economies,
save children, empower women, educate men,
and do all of that at once.
I'm not thinking any of those things are crazy.
It actually sounds really great.
It sounds like we probably should just do that anyway.
But hopefully we can also do that while sustainably building
a new food system, because we're going to need it.
There are these things called planetary boundaries
that environmental scientists identified.
Here's a graphic.
And as of now, we are pushing four
of these boundaries, biosphere integrity,
biogeochemical flows, that is phosphorus
and nitrogen, climate change, and land system change.
And we can't push all of these boundaries to the limit.
It would be bad.
This isn't like a West World.
You can't just push them all to max and say,
now you're awesome.
We are ruining the planet, and we're
going to start running out of food.
Hybridized wheat was a great invention.
We need the next hybridized wheat.
We were going to run out of oil.
So we started fracking mountains apart to get more.
We're going to run out of clean air.
So we better scrub it clean with these things
that we then have to throw away.
But you know, then we have this trash that's
filling up these landfills.
And we don't really have anywhere
to put it because the ocean animals are dying.
There is no solution where we can
continue living the same way.
We do not live in a robot.
We live in an ecosystem.
It's all about balance.
And it's funny.
A lot of people think nature is just like a robot.
It can be programmed and it behaves logically
and it self-heals.
But it doesn't.
Check out nature's weirdest events,
things like sinkholes and exploding toads.
Nature is so weird, y'all.
This is just one of the crazy amazing series
and documentaries on Curiosity Stream.
You should definitely use my link curiositystream.com/trace,
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It was nominated for a Streamy.
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And thank you.
So we know that we started expanding
into all the land on the planet several hundred years ago.
We cleared it, we threw cattle on it,
and cattle started to push out other animals, which
is just economics.
And we're still doing this in places like the Amazon.
Right now, we use 3 and 1/2 billion hectares of land
for food, which is roughly the size of Africa,
or about 1 and 1/2 North Americas.
And eventually, humans will have to push out the cattle.
Probably not before we destroy the planet, of course.
But instead, we need an economics reason
to not keep expanding, to not keep polluting.
We need incentives.
Denmark just recently created a set of taxes on red meat.
Maybe we should pay people to not cut down the Amazon?
What would that do?
How could that make the Amazon safer?
And are there other places we can do stuff like that?
Because if we've learned anything from this series,
economics is a pretty big pressure outside
of classism and evolution.
And it's not just who are here now who matter.
The billions who are going to be here in the future.
We live in an aquarium.
Eventually, we're going to run up against the walls.
And they are hard limits.
This ain't Finding Nemo.
We're not going to hop out the window.
It's not possible.
Not for all of us.
We need to change the calculation.
So what do we do when the Earth is full?
Only one thing that we can do that doesn't turn stomachs,
and that is leave.
I have a series on that.
You can watch it.
But when we do leave, we got to eat.
So what are we going to eat when we leave?
That's next time.
Thanks so much for watching the series
about thinking about food that we're eating all the time.
It's the holidays, so there's probably
a lot of eating going on, plus pandemic.
I don't know about you, but I got that COVID-19 going.
Long story short, thanks for watching.
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I am Trace.
I'll see you in the future.