A climate change solution that's right under our feet | Asmeret Asefaw Berhe

翻译人员: Li Ying (Amelia) Hu 校对人员: Lipeng Chen

So one of the most important solutions

气候变化带来了全球性的挑战，

to the global challenge posed by climate change

而应对这一挑战的一个 最重要的解决方案，

lies right under our foot every day.

每天都在我们的脚下。

It's soil.

土壤。

Soil's just the thin veil that covers the surface of land,

虽然土壤只是浅浅地覆盖着 地球表面的那一层，

but it has the power to shape our planet's destiny.

但它却能决定我们地球的命运。

See, a six-foot or so of soil,

一片厚度 6 英尺左右的土壤，

loose soil material that covers the earth's surface,

即覆盖着地球表面松松的土料，

represents the difference between life and lifelessness in the earth system,

可意味着在这地球上有无生命之别，

and it can also help us combat climate change

只要我们不视之如粪土，

if we can only stop treating it like dirt.

它还可以帮助我们应对气候变化。

(Laughter)

（笑声）

Climate change is happening,

气候正在发生变化，

the earth's atmosphere is warming,

地球的大气层正在变暖，

because of the increasing amount of greenhouse gases

因为我们不断向大气层释放

we keep releasing into the atmosphere.

越来越多的温室气体。

You all know that.

这是众所周知的。

But what I assume you might not have heard

但我猜想你们可能还没听说过，

is that one of the most important things our human society could do

为应对气候变化，

我们人类社会可以做的 最重要事情之一

to address climate change

lies right there in the soil.

就在这土壤里。

I'm a soil scientist who has been studying soil since I was 18,

我是一名土壤学家， 我从 18 岁起就开始研究土壤，

because I'm interested in unlocking the secrets of soil

因为我有兴趣揭开土壤的秘密，

and helping people understand this really important climate change solution.

并帮助人们了解这个十分重要的 气候变化解决方案。

So here are the facts about climate.

我来讲一下有关气候的实际情况。

The concentration of carbon dioxide in the earth's atmosphere

就在过去大约 150 年期间，

has increased by 40 percent

地球大气中的二氧化碳浓度

just in the last 150 years or so.

增加了 40%。

Human actions are now releasing 9.4 billion metric tons of carbon

人类活动现正向大气释放

into the atmosphere,

94 亿吨碳，

from activities such as burning fossil fuels

这些活动包括燃烧化石燃料、

and intensive agricultural practices,

进行密集的农业生产活动，

and other ways we change the way we use land,

以及我们改变土地用途的其他方法，

including deforestation.

包括砍伐森林。

But the concentration of carbon dioxide that stays in the atmosphere

但大气中的二氧化碳浓度

is only increasing by about half of that,

只约增加了一半，

and that's because half of the carbon we keep releasing into the atmosphere

这是因为我们不断释放到大气中的碳，

is currently being taken up by land and the seas

目前有一半正被陆地和海洋吸收，

through a process we know as carbon sequestration.

我们称这个过程为碳封存。

So in essence, whatever consequence you think we're facing

所以从根本上来说，不管你认为 我们现正面临气候变化

from climate change right now,

带来的后果是什么，

we're only experiencing the consequence of 50 percent of our pollution,

我们只遭受了 50% 的污染所产生的后果，

because the natural ecosystems are bailing us out.

因为自然生态系统在拯救我们。

But don't get too comfortable,

但是不要太过于掉以轻心了，

because we have two major things working against us right now.

因为现在有两件事对我们不利。

One: unless we do something big,

第一：除非我们采取大规模

and then fast,

且快速的行动，

emissions will continue to rise.

否则排放量将持续上升。

And second: the ability of these natural ecosystems

第二：自然生态系统有能力

to take up carbon dioxide from the atmosphere

从大气中吸收二氧化碳

and sequester it in the natural habitats

并将其隔离在自然栖息地，

is currently getting compromised,

而它的这一能力目前正受到损害，

as they're experiencing serious degradation because of human actions.

因为人类的活动， 这种能力正经历严重退化。

So it's not entirely clear

因此，如果我们继续 像往常一样行动，

that we will continue to get bailed out by these natural ecosystems

是否会继续得到这些 自然生态系统的帮助而摆脱困境，

if we continue on this business-as-usual path that we've been.

还尚不明确。

Here's where the soil comes in:

下面我来说说土壤的作用：

there is about three thousand billion metric tons of carbon in the soil.

土壤里约含有三万亿吨的碳，

That's roughly about 315 times the amount of carbon

这大约是我们目前释放到

that we release into the atmosphere currently.

大气中碳量的 315 倍，

And there's twice more carbon in soil than there is in vegetation and air.

土壤中的碳含量超出 植被和空气中的碳含量两倍多。

Think about that for a second.

我们就此来想一下，

There's more carbon in soil

土壤中的碳量

than there is in all of the world's vegetation,

大于世界上所有植被中的含量，

including the lush tropical rainforests and the giant sequoias,

这些植被包括茂密的热带雨林 和巨大的红杉、

the expansive grasslands,

广阔的草原、

all of the cultivated systems,

所有的耕地，

and every kind of flora you can imagine on the face of the earth,

以及你能想到 在地球表面的每一种植物群，

plus all the carbon that's currently up in the atmosphere, combined,

加上目前在大气中的所有的碳， 全部加起来，

and then twice over.

还多出两倍。

Hence, a very small change in the amount of carbon stored in soil

因此，土壤中所储存的 碳量有点小变化

can make a big difference in maintenance of the earth's atmosphere.

就能对维持地球大气产生很大的影响。

But soil's not just simply a storage box for carbon, though.

但是土壤不只是一个碳储存箱，

It operates more like a bank account,

它的运作更像是个银行账户，

and the amount of carbon that's in soil at any given time

在任何时候，土壤中的碳量

is a function of the amount of carbon coming in and out of the soil.

都跟进出土壤的碳量密切相关。

Carbon comes into the soil through the process of photosynthesis,

碳通过光合作用进入土壤，

when green plants take carbon dioxide from the atmosphere

绿色植物从大气中吸收二氧化碳，

and use it to make their bodies,

并用它来生长植物体，

and upon death, their bodies enter the soil.

植物死亡时，就会进入土壤，

And carbon leaves the soil

这些原来活着的生物体死后，

and goes right back up into the atmosphere

由于微生物的活动 使其在土壤中腐烂，

when the bodies of those formerly living organisms

这时碳离开土壤，

decay in soil by the activity of microbes.

再回到大气层。

See, decomposition releases carbon dioxide into the atmosphere,

腐烂分解释放出 二氧化碳进入大气，

as well as other greenhouse gases such as methane and nitrous oxide,

还有其他温室气体 如甲烷和一氧化二氮，

but it also releases all the nutrients we all need to survive.

但它还会释放出我们生存 所需的所有营养。

One of the things that makes soil such a fundamental component

土壤之所以是任何减缓气候变化战略

of any climate change mitigation strategy

的基本组成部分，

is because it represents a long-term storage of carbon.

原因之一就是因为它 代表着长期的碳储存。

Carbon that would have lasted maybe a year or two

如果碳被留在土壤表面，

in decaying residue if it was left on the surface

它可能会在腐烂的 残渣中留存一两年，

can stay in soil for hundreds of years, even thousands and more.

但碳在土壤里则可以保存数百年， 甚至数千年以上。

Soil biogeochemists like me

像我这样的土壤生物地球化学家

study exactly how the soil system makes this possible,

就在研究土壤系统 是如何使这成为可能的，

by locking away the carbon in physical association with minerals,

通过将碳锁在与矿物的物理联系中，

inside aggregates of soil minerals,

锁在土壤矿物的内部聚集物中，

and formation of strong chemical bonds

并形成牢固的化学键，

that bind the carbon to the surfaces of the minerals.

将碳与矿物表面结合在一起。

See when carbon is entrapped in soil,

当碳被包裹在土里，

in these kinds of associations with soil minerals,

与土壤矿物相结合，

even the wiliest of the microbes can't easily degrade it.

即使是最狡猾的微生物 也难以轻易地分解它。

And carbon that's not degrading fast

而无法快速降解的碳

is carbon that's not going back into the atmosphere as greenhouse gases.

是不会作为温室气体返回大气的。

But the benefit of carbon sequestration

但是，碳封存的好处

is not just limited to climate change mitigation.

不只是限于缓解气候变化，

Soil that stores large amounts of carbon is healthy, fertile, soft.

储存大量碳的土壤 会很健康、肥沃、柔软，

It's malleable. It's workable.

它具有适应性，适合耕种。

It makes it like a sponge.

碳让土壤变得像海绵，

It can hold on to a lot of water and nutrients.

它能保持大量的水分和营养。

Healthy and fertile soils like this

像这样健康肥沃的土壤

support the most dynamic, abundant and diverse habitat for living things

为我们所知的地球上 任何地方的生物都提供了

that we know of anywhere on the earth system.

最具活力、最丰富 和最多样的栖息地。

It makes life possible for everything from the tiniest of the microbes,

它使得各种生命得以维持， 从最微小的微生物，

such as bacteria and fungi,

如细菌和真菌，

all the way to higher plants,

一直到更高等的植物，

and fulfills the food, feed and fiber needs for all animals,

并满足所有动物，包括你和我，

对食物、饲料和纤维的需要。

including you and I.

So at this point, you would assume that we should be treating soil

说到这儿，你可能会认为

like the precious resource that it is.

我们应该将土壤视为宝贵资源，

Unfortunately, that's not the case.

不幸的是，事实并非如此。

Soils around the world are experiencing unprecedented rates of degradation

世界各地的土壤正在经历 前所未有的退化率，

through a variety of human actions that include deforestation,

这是人类各种行为所导致的， 包括砍伐森林、

intensive agricultural production systems,

密集的农业生产系统、

overgrazing,

过度放牧、

excessive application of agricultural chemicals,

过度使用农用化学品、

erosion and similar things.

腐蚀和类似的行为。

Half of the world's soils are currently considered degraded.

目前世界上有一半 的土壤被视为退化了。

Soil degradation is bad for many reasons,

从很多方面来说， 土壤退化都不是好事儿，

but let me just tell you a couple.

我来跟大家讲几个原因。

One: degraded soils have diminished potential to support plant productivity.

第一：退化了的土壤降低了 支持植物生长的潜力。

And hence, by degrading soil,

因此，人类的行为导致土壤退化，

we're compromising our own abilities to provide the food and other resources

同时也危及了我们自己 提供食物和其他资源的能力，

that we need for us

这些食物和其他资源是我们所需的，

and every member of living things on the face of the earth.

也是生存于地球上 的每一种生物所需的。

And second:

第二：

soil use and degradation, just in the last 200 years or so,

在过去的200年里， 土壤的利用和退化，

has released 12 times more carbon into the atmosphere

向大气中释放的碳

compared to the rate at which we're releasing carbon

是我们现在向大气中

into the atmosphere right now.

释放碳的速度的12倍。

I'm afraid there's even more bad news.

我得说还有更多坏消息，

This is a story of soils at high latitudes.

这是高纬度土壤的情况。

Peatlands in polar environments

在极地环境中的泥炭地

store about a third of the global soil carbon reserves.

储存着约三分之一 的全球土壤碳储量。

These peatlands have a permanently frozen ground underneath,

在这些泥炭地下面， 有一层永久冻结的土，

the permafrost,

即永久冻土，

and the carbon was able to build up in these soils over long periods of time

这些碳能够在这些土壤中长期累积，

because even though plants are able to photosynthesize during the short,

因为即使植物能够 在短暂且温暖的夏季

warm summer months,

进行光合作用，

the environment quickly turns cold and dark,

那里的环境会迅速地变冷， 天色变黑，

and then microbes are not able to efficiently break down the residue.

这样微生物就不能 有效地分解残留物。

So the soil carbon bank in these polar environments

因此，在过去的几十万年间，

built up over hundreds of thousands of years.

在极地环境中的土壤碳库存 得以日积月累。

But right now, with atmospheric warming,

但是现在，随着大气变暖，

the permafrost is thawing and draining.

永久冻土正在融化和流失，

And when permafrost thaws and drains,

而当永冻层融化并流失时，

it makes it possible for microbes to come in

微生物就有可能进入

and rather quickly decompose all this carbon,

并快速地分解所有这些碳，

with the potential to release hundreds of billions of metric tons of carbon

有可能以温室气体的形式

into the atmosphere in the form of greenhouse gases.

向大气释放数千亿吨碳。

And this release of additional greenhouse gases into the atmosphere

而这些向大气层释放 的额外温室气体

will only contribute to further warming

只会导致进一步暖化，

that makes this predicament even worse,

使这种困境更加恶化，

as it starts a self-reinforcing positive feedback loop

因为它开始了一个 自我增强的正反馈循环，

that could go on and on and on,

它会持续不断地循环，

dramatically changing our climate future.

极大地改变我们的气候未来。

Fortunately, I can also tell you that there is a solution

所幸的是，我们有一个办法，

for these two wicked problems of soil degradation and climate change.

来解决这两个糟糕的问题， 即土壤退化和气候变化。

Just like we created these problems,

就像我们制造了这些问题一样，

we do know the solution,

我们的确知道解决的办法，

and the solution lies in simultaneously working

那就是

to address these two things together,

要通过我们称之为 气候智能土地管理办法

through what we call climate-smart land management practices.

来同时处理这两个问题。

What do I mean here?

这是什么意思呢？

I mean managing land in a way that's smart

意思是要以明智的方式来管理土地，

about maximizing how much carbon we store in soil.

使土壤中的碳存量最大化。

And we can accomplish this

我们可以通过以下方式 来实现这一目标，

by putting in place deep-rooted perennial plants,

种植深根性的多年生植物，

putting back forests whenever possible,

尽可能恢复森林，

reducing tillage and other disturbances from agricultural practices,

减少耕作和其他农业活动的干扰，

including optimizing the use of agricultural chemicals and grazing

包括优化使用农用化学品和放牧，

and even adding carbon to soil, whenever possible,

甚至尽可能地用可循环利用的资源，

from recycled resources such as compost and even human waste.

如堆肥，甚至人类的排泄物， 给土壤添加碳。

This kind of land stewardship is not a radical idea.

这种土地管理并不是 一个激进的想法，

It's what made it possible for fertile soils

这是自古以来，让土壤肥沃，

to be able to support human civilizations since time immemorial.

使之能够抚育人类文明的方法。

In fact, some are doing it just right now.

事实上，现在有人正是这么做的。

There's a global effort underway to accomplish exactly this goal.

目前在全球范围内，人们 正在采取一项措施要实现这一目标，

This effort that started in France is known as the "4 per 1000" effort,

这项措施始于法国， 它被称为“千分之四”措施，

and it sets an aspirational goal

它设定了一个雄心勃勃的目标，

to increase the amount of carbon stored in soil by 0.4 percent annually,

每年将土壤中的碳存量增加 0.4%，

using the same kind of climate-smart land management practices

运用我前面提到的同样的

气候智能土地管理办法。

I mentioned earlier.

And if this effort's fully successful,

如果这项措施大获成功，

it can offset a third of the global emissions

那它可以抵消三分之一

of fossil-fuel-derived carbon into the atmosphere.

全球排放到大气层中的化石燃料碳。

But even if this effort is not fully successful,

但即使不完全成功，

but we just start heading in that direction,

我们只是开始朝着那个方向迈进，

we still end up with soils that are healthier, more fertile,

我们最终还是会获得 更健康、更肥沃的土壤，

are able to produce all the food and resources that we need

生产出我们所需的所有食物和资源，

for human populations and more,

满足人类的需求，

and also soils that are better capable

甚至土壤也能更好地

of sequestering carbon dioxide from the atmosphere

将大气中的二氧化碳隔离，

and helping with climate change mitigation.

帮助缓解气候变化。

I'm pretty sure that's what politicians call a win-win solution.

我很肯定，这就是政客们 所说的双赢解决方案。

And we all can have a role to play here.

我们大家都可以在此尽一份力，

We can start by treating the soil with the respect that it deserves:

我们可以从尊重土壤开始， 让其获得应有的尊重：

respect for its ability as the basis of all life on earth,

尊重其作为地球上 所有生命基础的能力，

respect for its ability to serve as a carbon bank

尊重其作为碳库的能力，

and respect for its ability to control our climate.

尊重其控制气候的能力。

And if we do so,

如果我们这么做，

we can then simultaneously address

我们就可以同时应对

two of the most pressing global challenges of our time:

我们这个时代最紧迫的 两个全球性的挑战：

climate change and soil degradation.

气候变化和土壤退化。

And in the process, we would be able to provide food and nutritional security

在这个过程中，我们将能够 为我们人类家庭的成长

to our growing human family.

提供足够的食物和营养保障。

Thank you.

谢谢。

(Applause)

（掌声）