Hey there and welcome to Life Noggin.
大家好！欢迎来到脑洞大开的生命奇想！
There are currently over 7 billion humans inhabiting the Earth and that value is increasing exponentially.
目前地球上有70亿人口，而且这个数字还在飞速增长。
So that has a lot of people wondering:, including me, “How many people can the Earth even hold?”
所以包括我在内的许多人都在思考，地球究竟能容纳多少人？
It’s estimated that, by the end of the century, the human population will be over 10 billion.
据估计，到本世纪末，地球上的人口会超过一百亿。
And scientists are unsure whether this will be sustainable or not.
而是否会继续增长，科学家们也不确定。
To see why, let’s start off by talking about my favorite subject: food.
究竟是为什么呢？我们先来说说我最喜欢的主题：食物。
If you were to take all the land being used to raise livestock and put it on one continent, it would take up all of Africa.
所有养牲畜的土地加起来，放在地球的某一个大陆上，可以覆盖整个非洲。
In fact, it would actually be greater than Africa, between 8 and 9 billion acres.
其实它比非洲还大一些，大约80到90亿英亩。
And if we did the same thing for crop production, it would take up an area about the size of South America.
再把所有种粮食的土地加起来，大约有一个南美洲那么大。
But, after a while, the soil in these areas will degrade, meaning its fertility decreases and it erodes, rendering it useless for growing crops.
但是，随着时间流逝，这些地方的土壤在退化，即土壤肥力下降，土壤流失，不再适宜种植作物。
And not only that, but scientists are unsure if farmers could even maintain their current crop yields due to changes in the environment.
不仅如此，科学家们也不确定，在环境变化的影响下，农民们还能不能保持当前的作物产量。
See, the global average of carbon dioxide emissions per person is about 5 metric tons per year.
看！全球人均二氧化碳排放是每年5公吨。
But for Americans, that average is closer to 17 metric tons per year.
但是美国人的人均排放接近每年17公吨。
And remember, this is per person.
记住，是人均！
So, if we have about 3 billion more people living on this planet, and they all adopt a lifestyle similar to an American,
所以，如果地球上再新增30亿人，他们又像美国人一样生活，
the effects of global warming will be worsened even more.
那么全球变暖会更加严重。
In fact, it’s projected that the temperature of the Earth will increase by 2 degrees Celsius by the end of the 21st century.
其实，有人已经预测，到21世纪末全球气温会上升2摄氏度。
And with that increase comes more extreme weather conditions, which would inevitably disrupt food production.
同时伴有极端天气，到时候食品生产必将受到极大影响。
So yeah, not good.
嗯~不太好！
Now, this can be partly remedied by everyone adopting a vegetarian diet, and reclaiming the land to grow more crops instead of raising livestock.
如果每个人都吃素，并且退牧还耕的话，情况会有所改善。
But the crops won’t be able to feed an infinite number of people.
但是农作物能养活的人口也是有限的。
In fact, some scientists predict that it would only be enough to feed 10 billion people.
有科学家预测，农作物只能养活100亿人口。
And more than likely, most people won’t switch to a vegetarian diet.
而且，大部分人不可能只吃素。
After all, bacon is a beautiful thing that exists.
毕竟，培根真的太美好了。
But what about the amount of available water?
那么，可用水量呢？
Humans are currently using about 30% of the Earth’s accessible renewable water supply,
人类目前用的是地球上30%的可持续利用的水资源，
with the rest being used for agriculture.
剩下的都用在了农业。
And the water available to some people in countries like: Ethiopia, Cambodia, and Haiti isn’t even clean enough to drink.
而埃塞俄比亚，柬埔寨和海地等国，没有干净的饮用水。
So, the amount reaching humans would have to increase with an increasing population.
所以人类所需的用水量与人口同步增长。
So, to answer the original question: the Earth may be able to hold a large number of people, perhaps even over 10 billion.
那么，回到开头的问题，地球可以容纳很多人，可能会有100亿多。
But the quality of those people’s lives would be much different than they are now.
但是人类的生活质量就远不如现在了。
So how many humans do you think the Earth can hold?
所以你认为地球可以容纳多少人口呢？
Or do you think we’re already there?
你觉得地球已经满载了吗？
Let me know in the comment section below.
欢迎在下方评论区留言。
Make sure you come back every Monday for a brand new video.
每周一都要回来看新视频哦。
As always, I’m Blocko and this has been Life Noggin.
我是宝高，这里是脑洞大开的生命奇想。
Don’t forget to keep on thinking!
思考不要停。