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  • So I assume you know that there's a lot of people on this planet. As of last week, Wednesday,

  • I think, was when we turned over to seven -- I --, nobody knows. But nobody knows exactly

  • how many people there are, it's kinda hard to keep track; it's a big planet. But there

  • are about seven billion people on the Earth right now.

  • And they keep getting born, all the time. In fact, for every 2 people who die, about

  • 4 are born. Every second, there are about four babies introducing themselves to this

  • world, and there are less than two people saying goodbye to it.

  • So, easy math here, our world's population is growing by about 2.5 people per second.

  • And as a reminder of this, during this video I'm going to have 2.5 ping pong balls being

  • thrown at me every single second throughout the entire rest of the video. Who's hitting

  • me in the face every single time?

  • [Intro]

  • Ok, instead of the balls, uh, were just gonna do a clock because I get nosebleeds pretty

  • easily, and I don't want you to have to see that.

  • So 7 billion people, it's hard to actually get your mind around how many people that

  • is, maybe if you were to just like sit down and count to 7 billion, it would take you

  • like 200 years or something.

  • On the other hand, there is plenty of space for them. If you took 7 billion people and

  • stood us shoulder to shoulder like we were at a Sting concert, those 7 billion people

  • could fit in an area the size of Los Angeles. We can fit on the Earth. There's space for

  • us all.

  • So as long as there's space for us all, what's the big deal about having 7 billion people?

  • Well it turns out people have been thinking about this for a long time, since around 1800,

  • when the world first clocked 1 billion people.

  • I know what you're thinking, you're like 1 billion, that's nothing, haha. Well at that

  • time all the economies in the world were based on agriculture. How much stuff we could grow

  • with human hands, farm animals, maybe a scythe and a wooden plow or something. So that kind

  • of technology, a billion people was really pushing it.

  • And the first like big-time thinker guy, to totally have a cow about there just being

  • too many freakin' people was a British economist named Thomas Malthus. Thomas Malthus calculated

  • that human populations tend to grow exponentially, while the ability of humans to feed each other

  • tends to grow more linearly. And so our growth as a species tends to outstrip our ability

  • to feed everyone.

  • And when that happens, it's pretty obvious what happens, you get the famine, and the

  • starvation. And for the people who are left over who don't die of those things, they can

  • get taken care of by disease and war.

  • Basically, Malthus thought that humanities natural state was to be cruel, miserable,

  • pathetic and sniveling in a pile of dirty underpants. In his essay on the principle

  • of population, Malthus observed... "The vices of mankind are active and able

  • ministers of depopulation. They are the precursors in the great army of destruction, and often

  • finish the dreadful work themselves. But should they fail in this war of extermination, sickly

  • seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their

  • thousands and tens of thousands. Should their success be still incomplete, gigantic inevitable

  • famine stalks in the rear, and with one mighty blow levels the population with the food of

  • the world."

  • Diseases also have an easier time taking hold, and of course starvation can kill off a lot

  • of people as well. Though he did make some pretty good points, as long as humanity is

  • well-fed, we're a pretty nice lot of people. But I have this problem too; when my blood

  • sugar just gets a little bit low, I start killing all of my neighbors -- that's not

  • actually true.

  • When you and your family's lives are threatened by starvation there's a lot of things that

  • you will do for food, including go to war. However, what Mister Doom and Gloom didn't

  • predict was the frickin' Industrial Revolution- which not only allowed the production of much

  • more food with far fewer laborers, it was also the impetus for this.

  • Uh, yeah. What that there is, is uh, the population of the Earth busting through Malthus's ceiling

  • and then his atmosphere and then his ozone layer and then his mesosphere and then his

  • - probably be pretty impressed by this. If you're not impressed yet, ah, just keep staring

  • at it. I can wait. I got all day.

  • It took humanity fifty thousand years to go from zero to one billion people, and then

  • to get from one billion to seven billion, about two hundred. So wow, Industrial Revolution,

  • thank you for allowing us to grow more food using machines, and for the fast and efficient

  • transportation that it takes to move all that food around to the people who needed it, and

  • thanks for the medical advances too, which help us understand things like the importance

  • of soap and the way that diseases worked, and as a result, humans now live about four

  • decades longer than the average guy in the eighteenth century.

  • Yeah! Industrial Revolution!

  • So Malthus might have been right about how frickin' stupid it was to be a human if the

  • Industrial Revolution had not happened. So now, the world's population is growing at

  • about 1.1 percent per year, which is a tiny bit better than the 1.3 percent per year that

  • got us here. If this current rate continues by 2050, we should have about 9.3 billion

  • people on the planet.

  • So the question is: at what point are these numbers going to outstrip our ability to feed

  • all of the people on the planet? It turns out actually that the question isn't how many

  • people can the Earth accommodate, it's more like: how many rich people can the Earth accommodate?

  • Because people in general, they tend to demand stuff for their survival like uh, oxygen,

  • water, and food. But rich people, we have different expectations. We, for example, in

  • America have a lot of agricultural crops, and we have to use a lot of fresh water to

  • water those agricultural crops. Do you want to take a guess at the number one irrigated

  • crop in the United States of America? Unless you've heard this statistic before, you were

  • wrong! It's grass! It takes more water to create lawns than it does to create all of

  • the corn in America.

  • We're using it like crazy; though it is a pretty scarce resource, we can use less than

  • one percent of the water on our planet. Most of it is salt water that we cannot use to

  • drink or irrigate crops, and 70 percent of our freshwater is frozen in glaciers. So clean

  • freshwater, non-negotiable and scarce. So what's next?

  • Ah, food. The world's combined food output could feed around 11 billion people, and yet,

  • there are 1 billion people who need food. So yeah that's one of the most pathetic and

  • infuriating things about our planet. So if there's enough food for 11 billion people,

  • and there's 7 billion people and a billion of them are hungry, who is eating all of our

  • food?

  • Food, is eating all that food. A huge amount of the food that we grow in America gets uh,

  • in turn eaten by livestock.

  • It's so hard to say the truth, which is that, but, rich people can do what they want. Now

  • when I say 'rich' it's important to note that I'm not talking about like, uh, the 99 percent

  • versus the 1 percent rich. I'm talking about if you have running water, electricity that

  • comes into your home, a computer that you can watch youtube videos on, and regularly

  • can afford to eat meat - you are a rich person on the earth, and you, you know sometimes

  • we just have to come to terms with the fact that we - even those of us who don't have

  • it great in America - have it better off than a whole lot of other people. There's a lot

  • of people in the world who don't get that. If you can have a hot shower, that's like

  • the peak of luxury to me.

  • So assuming that you are a first worlder, that you live in a developed country in Europe,

  • or you live in America or Japan, you consume on average as much stuff as 32 Kenyans. And

  • now the number of well-off people in the world is starting to increase dramatically and quickly,

  • and this is what we've always wanted for the world. So now we have all these moderately

  • well-off people walking around all over the planet, and it's great! Except that they require

  • more.

  • In the meantime though, a huge percentage of all of the babies that we're talking about

  • being born right now aren't being born to these rich people in the developed world.

  • They're being born in developing nations, and so the population isn't just growing.

  • It's growing in this weird, sort of scary, lopsided way.

  • Fact is, people in a lot of developed countries have kinda stopped having babies. Like Japan

  • for example, everybody's like 'Japan what are you doing? Why aren't you having any babies??'

  • and Japan's like 'Uhh don't know kinda don't feel like it.' So on average, Japanese people

  • are having about one baby per household. They're not even replacing themselves, compared to

  • two or three babies in America or like, five or six in most of Sub-Saharan Africa.

  • So developing nations are having a baby boom, and that's what happens when you get, you

  • know, vaccines and antibiotics and safe water and better sanitation. You get fewer babies

  • dying, and we are all completely and totally in favor of fewer babies dying, I hope. But

  • it also means that there are going to be a lot of new Sub-Saharan Africans in the next

  • 50 years or so, and that is where a lot of the 1 billion currently hungry people are

  • already living.

  • So while those of us in the developed world are not having any babies at all and yet consuming

  • enough food for like, four truckloads of babies, the governments in developing countries are

  • struggling with where to put all of these new people and how to feed them all. And you

  • also get what is known as a 'youth bulge'.

  • A lot of developing nations are currently seeing a huge explosion in people between

  • the ages of 15 and like 29. And all of those youth are out there, looking for the same

  • jobs, all at the same time, feeling generally hormonal as youth do, and being pretty unhappy

  • with their lot in life.

  • Some social scientists conjecture that youth bulges like this have been responsible for

  • nearly every insurrection in history, from the English revolution in 1640 to the more

  • recent Arab Spring. And neither of those things were bad things, but we should be aware that

  • there may be more of it coming.

  • And another thing that Reverend Malthus never thought of is: what happens when humanity

  • gets together and takes over the whole frickin' world? Seriously, because it turns out that

  • there are actually supposed to be some other things living on this planet with us.

  • Through our desire for more space and more stuff, we're putting pressure on pretty much

  • every habitat on earth. So much so that worldwide, 52 species of mammal, amphibian and bird move

  • one category closer to extinction every single year. You know, this world is pretty big,

  • but there's only so much room and it turns out that Bengal tigers aren't particularly

  • well-suited to high rise living. So the more there are of us, the fewer of literally everything

  • else there is, except for like, things that we enjoy eating, and petting - dogs and cats

  • as well; their populations continue to grow.

  • So happy birthday new people, welcome to Earth. I'll try not to screw it up too much for you.

  • If you're interested in more things to do with global population, please check out the

  • description below. There will be links in there for our source materials. You can also

  • ask us questions and leave ideas for future episodes of SciShow in the comments and get

  • in touch with us on Facebook and Twitter as well. Goodbye.

So I assume you know that there's a lot of people on this planet. As of last week, Wednesday,

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人口過多的科學 (The Science of Overpopulation)

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    簡宇謙 發佈於 2021 年 01 月 14 日
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