Human beings are everywhere.
人类无处不在。
With settlements on every continent, we can be found in the most isolated corners of Earth's jungles, oceans, and tundras.
安居在每一片大陆，我们存在于世界上最与世隔绝的丛林，海洋和平原。
Our impact is so profound, most scientists believe humanity has left a permanent mark on Earth's geological record.
我们的影响如此之深刻，以至于大多科学家们相信人类在这个地球上已留下了永久的痕迹。
So what would happen if suddenly, every human on Earth disappeared?
那么如果所有人都突然消失了，地球会怎么样呢？
With no one maintaining them, some of our creations backfire immediately.
当没有人维护时，我们的一些创造产物会立刻表现异常。
Hours after we disappear, oil refineries malfunction,
在我们消失后的几小时后，炼油厂会瘫痪，
producing month-long blazes at plants like the ones in western India, the southern United States, and South Korea.
并会持续数月地对周围植物喷射火焰；这种事会发生在印度西部，美国南部，还有南韩。
In underground rail systems like those in London, Moscow, and New York City,
而比如伦敦，莫斯科和纽约的地下铁路系统，
hundreds of drainage pumps are abandoned, flooding the tunnels in just three days.
数以百计的排水设施将被废弃，地下隧道将在三天内被洪水淹没。
By the end of the first week, most emergency generators have shut down,
一周之后，大多数应急发电机会关机，
and once the fires have gone out, the earth goes dark for the first time in centuries.
而当火也熄灭时，地球将会在这几个世纪以来第一次回到黑暗的怀抱。
After the first catastrophic month, changes come more gradually.
第一个多灾多难的月份过去之后，变化会慢慢放缓。
Within 20 years, sidewalks have been torn apart by weeds and tree roots.
20年之内，街道两侧会布满植草以及树根。
Around this time, flooded tunnels erode the streets above into urban rivers.
这段时间，被水淹没的隧道已经生锈，而上面的街道变成的河流。
In temperate climates, the cycle of seasons freezes and thaws these waterways, cracking pavement and concrete foundations.
在温带气候的环境中，随着季节循环，这些水流时冻时化，对周围街道和坚固设施产生冲击和破坏。
Leaking pipes cause the same reaction in concrete buildings, and within 200 winters, most skyscrapers buckle and tumble down.
漏水的管道在大楼中也会造成同样的破坏，大多数摩天大楼撑不过两百个冬天就会崩裂倒塌。
In cities built in river deltas like Houston,
在如休斯顿这种依河流三角洲所建的城市里，
these buildings eventually wash away completely -- filling nearby tributaries with crushed concrete.
这些大楼将被完全冲走--致使周围的水域布满破碎的钢筋水泥。
Rural and suburban areas decay more slowly, but in largely unsurprising ways.
郊区和乡村的衰败会缓慢一些，但大多会以不出乎意料的方式进行。
Leaks, mold, bug and rodent infestations -- all the usual enemies of the homeowner -- now go uncontested.
漏水、霉菌、虫害以及鼠害--那些家户常见的敌人--现在肆无忌惮了。
Within 75 years, most houses' supporting beams have rotted and sagged,
75年之内，大多数房屋的支撑横梁会腐败、下陷，
and the resulting collapsed heap is now home to local rodents and lizards.
而造成的坍塌就成了当地的老鼠和蜥蜴的家园。

But in this post-human world, "local" has a new meaning.
但是在这个后人类的世界，“土生土长”有了全新的含义。
Our cities are full of imported plants, which now run wild across their adopted homes.
充满入侵植物的城市，将被肆意生长的它们完全占领。
Water hyacinth coat the waterways of Shanghai in a thick green carpet.
凤眼蓝将在上海的水道上形成一层厚厚的绿色覆盖。
Poisonous giant hogweeds overgrow the banks of London's Thames River.
有毒的大型大豕草将漫上英国泰晤士河的河岸。
Chinese Ailanthus trees burst through New York City streets.
中国臭椿将占领纽约市的街道。
And as sunken skyscrapers add crumbled concrete to the new forest floor,
而且当塌陷的摩天大楼给新的森林地表增加建筑残块时，
the soil acidity plummets, potentially allowing new plant life to thrive.
土地酸度会急剧上升，给了新植物潜在的繁荣生长的机会。
This post-human biodiversity extends into the animal kingdom, as well.
这种后人类的生态多样性同样也延伸到了动物世界。
Animals follow the unchecked spread of native and non-native plants, venturing into new habitats with the help of our leftover bridges.
动物追随本地或引进植物无限制的扩张，依靠我们留下的桥梁进入新的领地。
In general, our infrastructure saves some animals and dooms others.
总的来说，我们的基建拯救了一些动物，同时也毁灭了另一些动物。
Cockroaches continue to thrive in their native tropical habitats,
蟑螂继续在它们原产的热带领域繁衍生息，
but without our heating systems, their urban cousins likely freeze and die out in just two winters.
但是没有了我们的供暖系统，它们在城市的种群将在两个冬天受冻，最终消亡。
And most domesticated animals are unable to survive without us -- save for a handful of resourceful pigs, dogs, and feral housecats.
大多数家养动物在没有我们的情况下将无法生存--仅剩下一些机智的猪、狗以及家猫。
Conversely, the reduced light pollution saves over a billion birds each year
相反，削减的光污染每年将拯救超过十亿只候鸟，
whose migrations were disrupted by blinking communication tower lights and high-tension wires.
因为以往它们的迁徙受到闪亮的信号灯以及高压电线的阻碍。
And mosquitos multiply endlessly in one of their favorite manmade nurseries -- rubber tires, which last for almost a thousand years.
蚊子将在它们最爱的人造乐园之一--橡胶轮胎中继续繁衍生息超过千年。
As fauna and flora flourish, Earth's climate slowly recovers from millennia of human impact.
随着动植物不断繁衍，地球的气候将从人类数千年的影响中逐渐恢复过来。
Within 35,000 years, the plant cycle removes the last traces of lead left by the Industrial Revolution from Earth's soil,
35000年以内，植物循环将从土地中移除工业革命留下的最后一丁点铅，
and it may take up to 65,000 years beyond that for CO2 to return pre-human levels.
而二氧化碳量将至少需要65000年才能回到人类文明前的水平。
But even after several million years, humanity's legacy lives on.
但是即使数百万年之后，人类的遗产依然存在。
Carved in unyielding granite, America's Mt. Rushmore survives for 7.2 million years.
它们被雕刻在坚硬的花岗岩中，美国的拉什莫尔山将存在720万年。
The chemical composition of our bronze sculptures keeps them recognizable for over 10 million.
我们的铜制雕塑因其化学成分将留存超过1000万年的时间。
And buried deep underground, the remnants of cities built on floodplains have been preserved in time as a kind of technofossil.
深埋在地下，建造在涝原上的城市的废墟，将以化石的形式被保留下来。
Eventually, these traces, too, will be wiped from the planet's surface.
最终，这些遗迹也会被从地球表面抹去。
Humanity hasn't always been here, and we won't be here forever.
人类文明并非亘古永存，我们也不会永久存在。
But by investigating the world without us, perhaps we can learn more about the world we live in now.
但是通过考察没有我们的世界，也许我们可以更好地了解我们现在赖以生存的世界。