The most massive

厲害的海嘯風暴

tsunami perfect storm

正臨頭痛擊我們

is bearing down upon us.

這場厲害的風暴

This perfect storm

正造成嚴峻的事實 日益嚴峻的事實

is mounting a grim reality, increasingly grim reality,

而我們面對這事實的態度

and we are facing that reality

是全然地相信

with the full belief

我們可以用科技解決這個問題

that we can solve our problems with technology,

而這是非常可以理解的

and that's very understandable.

那麼，我們面對的這場厲害風暴

Now, this perfect storm that we are facing

是我們人口增加的結果

is the result of our rising population,

攀升至近百億的人口

rising towards 10 billion people,

土地變成沙漠

land that is turning to desert,

當然，還有氣候變遷

and, of course, climate change.

那麼，無庸置疑的

Now there's no question about it at all:

我們只能以科技

we will only solve the problem

代替石化燃料以解決這個問題

of replacing fossil fuels with technology.

但石化燃料、碳——煤及石油——

But fossil fuels, carbon -- coal and gas --

絕不是導致氣候變遷的

are by no means the only thing

唯一理由

that is causing climate change.

沙漠化

Desertification

是形容土地變成沙漠的華麗名詞

is a fancy word for land that is turning to desert,

而這種情況是因為

and this happens only when

我們造出太多裸露的土地

we create too much bare ground.

沒有其他的原因了

There's no other cause.

而我刻意要把重點放在

And I intend to focus

全球那些變成沙漠的土地

on most of the world's land that is turning to desert.

但我要提出一個非常簡單的方法

But I have for you a very simple message

能提供更多超乎想像的希望

that offers more hope than you can imagine.

我們有

We have environments

終年溼氣不斷的環境

where humidity is guaranteed throughout the year.

在這些地方，幾乎不可能

On those, it is almost impossible

產生大面積裸露土壤

to create vast areas of bare ground.

無論你怎麼做 大自然都能快速覆蓋它

No matter what you do, nature covers it up so quickly.

而我們也有這樣的環境

And we have environments

是我們有幾個月的濕氣

where we have months of humidity

然後接著是好幾個月的乾旱

followed by months of dryness,

而這就是沙漠化發生之處

and that is where desertification is occurring.

幸運的是，現在因著太空科技

Fortunately, with space technology now,

我們可以從太空觀察它

we can look at it from space,

如此做，我們相當能清楚地看見比例

and when we do, you can see the proportions fairly well.

一般來說，你所見綠色之處

Generally, what you see in green

就是沒有沙漠化的地方

is not desertifying,

棕色處則是發生沙漠化的地方

and what you see in brown is,

這些是迄今世上最大的幾處

and these are by far the greatest areas of the Earth.

我猜，大約三分之二的 全球土地正經歷沙漠化

About two thirds, I would guess, of the world is desertifying.

我在提哈馬沙漠拍了這張照片

I took this picture in the Tihamah Desert

當時降雨量為25公釐 大約是一英寸的雨量

while 25 millimeters -- that's an inch of rain -- was falling.

以汽油桶裝水來想像一下

Think of it in terms of drums of water,

每桶可裝二百公升的水

each containing 200 liters.

那天，那塊地每公頃上

Over 1,000 drums of water fell on every hectare

降下了超過一千桶的水

of that land that day.

但隔天，那塊地看起來變成這樣

The next day, the land looked like this.

那些水都去了哪裡？

Where had that water gone?

有些變成了溢流跑掉了

Some of it ran off as flooding,

但大部分浸入土裡的水

but most of the water that soaked into the soil

就只是再蒸發掉了

simply evaporated out again,

完全就像你家花園的情況一樣

exactly as it does in your garden

如果你讓花園土壤裸露

if you leave the soil uncovered.

那麼，因為水及碳的循環

Now, because the fate of water and carbon

與土壤有機質息息相關

are tied to soil organic matter,

當我們破壞了土壤，你就釋放了碳

when we damage soils, you give off carbon.

碳會回到大氣層

Carbon goes back to the atmosphere.

你一遍又一遍地聽到人再三地說

Now you're told over and over, repeatedly,

沙漠化只能發生在

that desertification is only occurring

地球的乾旱及半乾旱氣候區

in arid and semi-arid areas of the world,

而像這樣的高草地

and that tall grasslands like this one

因降雨量高，不會發生這現象

in high rainfall are of no consequence.

但是如果你不看其上之草 只看其下的土壤

But if you do not look at grasslands but look down into them,

你會發現你剛剛所見的草原

you find that most of the soil in that grassland

其土壤都裸露並被苔原覆蓋

that you've just seen is bare and covered with a crust of algae,

造成逕流增加及水分蒸發

leading to increased runoff and evaporation.

那就是我們未能早期發現的

That is the cancer of desertification

沙漠化惡瘤，直到它已惡化到末期

that we do not recognize till its terminal form.

現在我們知道沙漠化是因家畜造成

Now we know that desertification is caused by livestock,

大部分是養牛、綿羊及山羊

mostly cattle, sheep and goats,

過度放牧造成植被無法復原

overgrazing the plants,

使得土壤裸露並釋放甲烷

leaving the soil bare and giving off methane.

幾乎大家都知道這個現象

Almost everybody knows this,

從諾貝爾獎得主到高爾夫球桿弟

from nobel laureates to golf caddies,

或者至少你被教導過，像我一樣

or was taught it, as I was.

你在這張圖看到的

Now, the environments like you see here,

塵土飛揚的環境，那是我的家鄉非洲

dusty environments in Africa where I grew up,

我很愛野生動物

and I loved wildlife,

所以我長大後非常恨惡家畜

and so I grew up hating livestock

因為牠們造成許多破壞

because of the damage they were doing.

我的大學教育讓我成為生物學者

And then my university education as an ecologist

更加堅固了我的信仰

reinforced my beliefs.

但是，我要告訴你

Well, I have news for you.

我們曾經如此堅信

We were once just as certain

世界是平的

that the world was flat.

然後發現我們錯了 現在我們發現我們又錯了

We were wrong then, and we are wrong again.

我要邀請你

And I want to invite you now

與我一同走過我被 再教育及重新發現的旅程

to come along on my journey of reeducation and discovery.

當我還很年輕，在非洲

When I was a young man,

還是一個沒經驗的生物學家時

a young biologist in Africa,

我參與一項計畫，要把幾片壯麗的土地

I was involved in setting aside marvelous areas

預留成未來的國家公園

as future national parks.

沒多久──這是1950年代

Now no sooner — this was in the 1950s —

沒多久，我們就把一群以狩獵

and no sooner did we remove the hunting,

敲鼓為生的人移居以保護動物

drum-beating people to protect the animals,

然後這塊地的情況就開始惡化

than the land began to deteriorate,

就像你看到的這個 我們弄出來的公園一樣

as you see in this park that we formed.

那麼，雖然沒有家畜了

Now, no livestock were involved,

但我們懷疑有太多大象

but suspecting that we had too many elephants now,

我做了個研究證明的確如此

I did the research and I proved we had too many,

所以我建議我們要降低其數目

and I recommended that we would have to reduce their numbers

且要降到這片土地 可以自給自足的水平

and bring them down to a level that the land could sustain.

對我而言 那是個不得不的可怕決定

Now, that was a terrible decision for me to have to make,

而老實說也是政治炸彈

and it was political dynamite, frankly.

所以我們的政府組了一個專家團隊

So our government formed a team of experts

來評估我的研究

to evaluate my research.

他們的確做了，也與我持相同意見

They did. They agreed with me,

所以接下來幾年

and over the following years,

我們射殺了四萬頭大象 試圖停止土地破壞

we shot 40,000 elephants to try to stop the damage.

然而事情變得更糟，沒有更好

And it got worse, not better.

我是如此愛著大象

Loving elephants as I do,

那真是我一生中最難過 也是最大的失誤

that was the saddest and greatest blunder of my life,

終其一生我都將懷著悔恨

and I will carry that to my grave.

但痛定思痛，還是有件好事

One good thing did come out of it.

它讓我矢志不移

It made me absolutely determined

要畢生投入以找出解決方案

to devote my life to finding solutions.

當我到美國時我很震驚

When I came to the United States, I got a shock,

發現像這樣的國家公園

to find national parks like this one

其沙漠化的程度就跟非洲的一樣糟

desertifying as badly as anything in Africa.

而且這片土地已超過

And there'd been no livestock on this land

70年的時間沒有家畜

for over 70 years.

而且我發現美國科學家

And I found that American scientists

除了說它是乾旱及自然現象外

had no explanation for this

對此沒有任何解釋

except that it is arid and natural.

所以我開始在

So I then began looking

我能找到的

at all the research plots I could

針對美西的研究報告中尋找

over the whole of the Western United States

牛隻遷移

where cattle had been removed

真的可以停止沙漠化的證明

to prove that it would stop desertification,

但我發現的是完全相反的證明

but I found the opposite,

如同我們在這個研究站看到的

as we see on this research station,

1961年這片草地還是綠油油一片

where this grassland that was green in 1961,

但到了2002年已經變成這樣

by 2002 had changed to that situation.

而寫這篇氣候變遷意見書的作者

And the authors of the position paper on climate change

我就是從那裏拿到這些照片

from which I obtained these pictures

把此改變歸因於未知現象

attribute this change to "unknown processes."

很明顯我們並不了解

Clearly, we have never understood

沙漠化的原因

what is causing desertification,

而此現象已經毀滅了許多文明

which has destroyed many civilizations

而現在正對我們產生全球性威脅

and now threatens us globally.

我們從來沒有了解過這件事

We have never understood it.

把一平方公尺的土壤

Take one square meter of soil

像這樣光禿禿攤平在這裡

and make it bare like this is down here,

我保證你會發現，這片土與僅由

and I promise you, you will find it much colder at dawn

枯枝落葉覆蓋住的同樣土壤

and much hotter at midday

在破曉時冷得多，在日正當中時熱得多

than that same piece of ground if it's just covered with litter,

只要枯枝落葉就好

plant litter.

你就改變了微氣候

You have changed the microclimate.

所以，當你這麼做

Now, by the time you are doing that

並在超過全球一半的土地

and increasing greatly the percentage of bare ground

大幅增加裸露地面的百分比時

on more than half the world's land,

你就在改變總體氣候

you are changing macroclimate.

但我們就是不了解

But we have just simply not understood

為什麼這現象於一萬年前開始發生？

why was it beginning to happen 10,000 years ago?

為什麼最近大幅加快？

Why has it accelerated lately?

我們對其一無所知

We had no understanding of that.

我們並沒有了解到

What we had failed to understand

這些隨季節改變濕度的環境

was that these seasonal humidity environments of the world,

其土壤及植被的發展

the soil and the vegetation

與非常大數目的放牧有關

developed with very large numbers of grazing animals,

也沒有了解到這些放牧動物

and that these grazing animals

與兇猛的群體狩獵掠食動物息息相關

developed with ferocious pack-hunting predators.

那麼，要對抗群體狩獵掠食 動物的主要方法

Now, the main defense against pack-hunting predators

就是集結成群

is to get into herds,

而且群體愈大，個體就愈安全

and the larger the herd, the safer the individuals.

大群動物在其食物上排便及尿

Now, large herds dung and urinate all over their own food,

牠們還必須遷徙

and they have to keep moving,

而也就是這個遷徙

and it was that movement

避免了過度放牧

that prevented the overgrazing of plants,

而時時遷徙

while the periodic trampling

確保土壤覆蓋良好

ensured good cover of the soil,

就像我們看到一群動物走過後的樣子

as we see where a herd has passed.

這張照片是典型的季節性草原

This picture is a typical seasonal grassland.

它剛剛經歷了四個月的雨季

It has just come through four months of rain,

現在正進入為期八個月的乾季

and it's now going into eight months of dry season.

請注意看它進入長時間乾季後的改變

And watch the change as it goes into this long dry season.

現在，所有長在地上的草

Now, all of that grass you see aboveground

在下個生長期前

has to decay biologically

都要腐爛，要不然

before the next growing season, and if it doesn't,

整片草原及土壤就會開始死亡

the grassland and the soil begin to die.

那麼，如果它沒有腐爛

Now, if it does not decay biologically,

就會轉變成氧化作用 而這是非常慢的過程

it shifts to oxidation, which is a very slow process,

而這會使草窒息死亡

and this smothers and kills grasses,

使原本的草地轉變成木本植被

leading to a shift to woody vegetation

及裸露的土壤，釋放碳

and bare soil, releasing carbon.

要避免此現象 傳統的方法是使用火燒

To prevent that, we have traditionally used fire.

但火一樣會使土地裸露，釋放碳

But fire also leaves the soil bare, releasing carbon,

且更糟的是

and worse than that,

每燒一公頃的草地

burning one hectare of grassland

比六千輛車所造成的汙染跟破壞，

gives off more, and more damaging, pollutants

都大上許多

than 6,000 cars.

但我們卻每年都在非洲

And we are burning in Africa, every single year,

燒掉超過十億公頃的草原

more than one billion hectares of grasslands,

卻幾乎沒人在意

and almost nobody is talking about it.

身為科學家，我們辯稱

We justify the burning, as scientists,

燃燒能移除已死的物質

because it does remove the dead material

讓植物能夠生長

and it allows the plants to grow.

現在，眼看著我們這片草原變成荒蕪

Now, looking at this grassland of ours that has gone dry,

到底我們能要怎麼做 才能讓它保持健康？

what could we do to keep that healthy?

請記住，我現在談的是 全球大部分的土地

And bear in mind, I'm talking of most of the world's land now.

好嗎？我們不能降低動物 數目以復原更多土地

Okay? We cannot reduce animal numbers to rest it more

卻不造成沙漠化及氣候變遷

without causing desertification and climate change.

我們無法燒了它

We cannot burn it without causing

卻不造成沙漠化及氣候變遷

desertification and climate change.

我們到底要怎麼做？

What are we going to do?

只有一個選擇

There is only one option,

我再說一次，只有一個選擇

I'll repeat to you, only one option

留給氣象學家及科學家

left to climatologists and scientists,

就是要做匪夷所思之事

and that is to do the unthinkable,

要用蓄養牲畜

and to use livestock,

要一群一群養，還要遷徙

bunched and moving,

就像之前牧群及掠食者一樣

as a proxy for former herds and predators,

模仿大自然的運作

and mimic nature.

我們沒有其他替代方案了

There is no other alternative left to mankind.

所以就開始做吧

So let's do that.

所以我們就在這塊草原上實行 但僅限在草原前端

So on this bit of grassland, we'll do it, but just in the foreground.

我們放置牲畜 倣效自然界運作

We'll impact it very heavily with cattle to mimic nature,

而我們的確也做到了，看到沒

and we've done so, and look at that.

現在滿滿的草覆蓋著這塊土壤

All of that grass is now covering the soil

因為有糞、尿、枯枝落葉及覆蓋物

as dung, urine and litter or mulch,

就像在座的園藝愛好者都能了解這個現象

as every one of the gardeners amongst you would understand,

這片土壤已準備就緒 可以吸收保留雨水

and that soil is ready to absorb and hold the rain,

可以儲存碳，可以分解甲烷

to store carbon, and to break down methane.

我們這樣做

And we did that,

不需用火破壞土壤

without using fire to damage the soil,

而植物可以自由生長

and the plants are free to grow.

當我第一次了解到

When I first realized

身為科學家，我們別無選擇

that we had no option as scientists

只能用惡名昭彰的家畜

but to use much-vilified livestock

來解釋氣候變遷及沙漠化時

to address climate change and desertification,

我面對著一個真正的兩難問題

I was faced with a real dilemma.

我們是怎麼搞成這樣的？

How were we to do it?

我們在過去一萬年 有非常有知識的放牧者

We'd had 10,000 years of extremely knowledgeable pastoralists

群集趕放動物

bunching and moving their animals,

但造成了世上大規模的人造沙漠

but they had created the great manmade deserts of the world.

然後我們在僅一百年的 先進降雨科學發展下

Then we'd had 100 years of modern rain science,

卻加速了沙漠化的發展

and that had accelerated desertification,

就像我們首先在非洲發現的

as we first discovered in Africa

然後在美國也得到確認

and then confirmed in the United States,

就如同你在這張照片看到的

and as you see in this picture

由聯邦政府管理的土地一樣