How long will human impacts last? - David Biello

翻译人员: Siyuan Qi 校对人员: vivian qian

Imagine aliens land on the planet a million years from now

设想一百万年后外星人登陆地球，

and look into the geologic record.

并且查看地质记录。

What will these curious searchers find of us?

这些好奇的探索者会找到 关于我们的什么信息呢？

They will find what geologists, scientists, and other experts

他们会找到“人类世”的痕迹，

are increasingly calling the Anthropocene,

这个名词被越来越多地质学家、 科学家和其他专家使用，

or new age of mankind.

意思是属于人类的新世纪。

The impacts that we humans make have become so pervasive,

人类所产生的影响变得越来越普遍，

profound,

越来越深入，

and permanent

越来越持久。

that some geologists argue we merit our own epoch.

于是一些地质学家认为 应该有一个关于人类的新纪元。

That would be a new unit in the geologic time scale

这个纪元是一个新的地质单元，

that stretches back more than 4.5 billion years,

可以追溯到 45 亿年前，

or ever since the Earth took shape.

或者地球形成时。

Modern humans may be on par with the glaciers behind various ice ages

现代人类可能就与冰河时代的冰川

or the asteroid that doomed most of the dinosaurs.

以及造成恐龙灭绝 的小行星并驾齐驱了。

What is an epoch?

纪元是什么？

Most simply, it's a unit of geologic time.

简单来讲，纪元 是地质时间的一个单元，

There's the Pleistocene,

比如有更新世，

an icy epoch that saw the evolution of modern humans.

一个见证了现代人类演进的冰川纪元。

Or there's the Eocene, more than 34 million years ago,

比如有始新世，3400 多万年前 的一个地球活跃时间段。

a hothouse time during which

在此期间，

the continents drifted into their present configuration.

大陆漂移成了现在的结构。

Changes in climate or fossils found in the rock record

气候变化和岩石记录中找到的化石

help distinguish these epochs and help geologists tell deep time.

能帮助我们区分这些纪元， 帮助地质学家识别更久远的时间。

So what will be the record of modern people's impact on the planet?

现代人类对于地球的影响， 会产生怎样的记录呢？

It doesn't rely on the things that may seem most obvious to us today,

这并不取决于我们今天 所见到的最显眼的东西，

like sprawling cities.

例如连绵不绝的城市。

Even New York or Shanghai may prove hard to find

即便像纽约和上海这样的城市，

buried in the rocks a million years from now.

也可能被埋在一百万年后 的岩石下，踪迹难寻。

But humans have put new things into the world

但是人类将新东西带到了世界上。

that never existed on Earth before,

这些新东西是地球之前没有的，

like plutonium

例如钚

and plastics.

和塑料。

In fact, the geologists known as stratigraphers

事实上，地质学家中 负责测定地质时间

who determine the geologic timescale,

的地层学家提出，

have proposed a start date for the Anthropocene around 1950.

“人类世”的开始时间大约在 1950 年。

That's when people started blowing up nuclear bombs all around the world

在那时，人们开始 在世界范围内投放原子弹，

and scattering novel elements to the winds.

使新元素大量扩散。

Those elements will last in the rock record,

这些元素会留存在岩石记录中，

even in our bones and teeth for millions of years.

甚至在我们的骨头 和牙齿中留存数百万年。

And in just 50 years, we've made enough plastic,

在仅仅 50 年中， 我们所生产的塑料

at least 8 billion metric tons,

就达到了 80 亿公吨以上，

to cover the whole world in a thin film.

足以在地球表面覆盖一个薄层。

People's farming, fishing, and forestry will also show up as a before and after

人类的农业、林业、渔业活动

也会先后表现在地层中,

in any such strata

because it's those kinds of activities

因为是这些活动

that are causing unique species of plants and animals to die out.

导致了稀有的动植物物种灭绝。

This die-off started perhaps more than 40,000 years ago

这种灭绝情况也许在 4 万年前

as humanity spread out of Africa

人类走出非洲时就开始了，

and reached places like Australia,

我们的祖先到达了 像澳大利亚这样的地方，

kicking off the disappearance of big, likable, and edible animals.

开启了大型、可爱、 可食用的动物的消失进程。

This is true of Europe and Asia, think woolly mammoth,

在欧洲和亚洲是这样的， 想一想长毛猛犸象就知道，

as well as North and South America, too.

北美和南美洲的动物也难逃一劫。

For a species that has only roamed

对于一个仅仅在地球上

the planet for a few hundred thousand years,

出现了几十万年的物种来说，

Homo sapiens has had a big impact on the future fossil record.

智人对于未来的化石记录 产生了巨大的影响。

That also means that even if people were to disappear tomorrow,

这也意味着，即便人类明天就消失，

evolution would be driven by our choices to date.

我们至今为止做出的选择 也会推动演进过程。

We're making a new homogenous world of certain favored plants and animals,

我们正在创造一个同质化的世界， 有利于一些特定的动植物，

like corn and rats.

如谷物和老鼠。

But it's a world that's not as resilient as the one it replaces.

但是这个世界不如 原来的世界适应能力强。

As the fossil record shows,

化石记录表明，

it's a diversity of plants and animals

是植物和动物的多样性

that allows unique pairings of flora and fauna

使得特定动植物群

to respond to environmental challenges, and even thrive after an apocalypse.

有可能去应对环境威胁， 甚至在大灾难之后依然繁衍生息。

That goes for people, too.

这点对于人类也是一样。

If the microscopic plants of the ocean suffer

假设过多的二氧化碳

as a result of too much carbon dioxide, say,

导致海洋微生植物受损，

we'll lose the source of as much as half of the oxygen we need to breathe.

我们会失去现在一半的氧气来源。

Then there's the smudge in future rocks.

然后是未来岩石中的污迹。

People's penchant for burning coal, oil, and natural gas

人类对于燃烧煤、 石油、天然气的偏好

has spread tiny bits of soot all over the planet.

使细小的煤烟在地球上蔓延。

That smudge corresponds with a meteoric rise

这种煤烟会导致空气中

in the amount of carbon dioxide in the air,

二氧化碳含量激增，

now beyond 400 parts per million,

目前空气中二氧化碳含量 已经超过了400 ppm，

or higher than any other Homo sapiens has ever breathed.

或者说比以前所有智人呼吸过 的空气中的二氧化碳含量还要高。

Similar soot can still be found in ancient rocks

类似的煤烟也能在古岩石中找到，

from volcanic fires of 66 million years ago,

这些岩石来自 6600 万年前的火山喷发，

a record of the cataclysm touched off by an asteroid

它记录下了在白垩纪末期

at the end of the late Cretaceous epoch.

由小行星引发的一场大灾难。

So odds are our soot will still be here 66 million years from now,

因此我们的煤烟也有可能 在 6600 万年后仍然存在，

easy enough to find for any aliens who care to look.

很容易被细心的外星人找到。

Of course, there's an important difference between us and an asteroid.

当然，我们和小行星之间 有一个很大的区别。

A space rock has no choice but to follow gravity.

宇宙岩石除了 遵循重力规则外别无选择。

We can choose to do differently.

但是我们可以选择做不一样的事情。

And if we do, there might still be some kind of human civilization thousands

如果我们行动起来， 几千年，甚至几百万年后，

or even millions of years from now.

仍然会有人类文明的存在，

Not a bad record to hope for.

希望这会是一个不错的记录。