What Seaweed and Cow Burps Have to Do with Climate Change | Ermias Kebreab | TED Countdown

譯者: Fred Tsang 審譯者: Shelley Tsang 曾雯海

由於我們吃肉以及飲用乳製品的習慣，

Pasture is the single largest type of land

on the surface of the Earth today,

牧場儼然成為當今地球上

thanks to our taste for meat and dairy.

占地最大的土地利用方式。

Just over a quarter of all land is used for livestock.

畜牧業就佔了四分之一的土地。

That's more than forests or farm fields or anything else.

這比森林、農田 或是任何其他利用方式還來的多。

Most of that land is best for ruminants,

大部分牧場最適合養反芻動物，

such as cows,

像是牛，

that can digest high-fiber feed such as grass and straw.

這類動物可以消化高纖飼料 例如牧草或是稻草。

However, the process by which grass and fiber is broken up

然而，在這些反芻動物

in the stomachs of cows and other grazing ruminants

在消化牧草和纖維的過程中

has a byproduct, methane,

腸胃也會產出甲烷這類副產物。

a potent greenhouse gas.

甲烷是種很強的溫室氣體。

Despite what you might have heard about methane and cows,

你可能聽過甲烷和牛的關聯，

most of the methane is actually burped out,

但其實大部分甲烷不是牛「放出來」，

not through the back end.

而是「嗝出來」的。

(Laughter)

（笑聲）

And that represents about two billion tons

這相當於每年

of carbon dioxide equivalent per year,

二十億噸的二氧化碳當量

or more than four percent of our annual global greenhouse gas emissions.

或是超過每年溫室氣體 排放量的百分之四。

We have a methane problem from cows.

牛排放的甲烷 確實已經成爲一個問題了。

So how can you reduce these methane burps?

那我們該怎麼減少這些甲烷呢？

My colleagues and I may have found a solution.

我和我的同事找到一個方法。

Seaweed!

海藻！

Let me explain.

請容我解釋一下。

A couple of years ago,

數年前，

an article was published by Rob Kinley and colleagues

羅布·金利 (Rob Kinley)和他的同事 發表了一篇論文，

that showed almost complete elimination of methane

實驗結果顯示 剁碎的草在加入海藻之後，

when seaweed was added to chopped grass in the lab.

幾乎可以不排出甲烷。

Great.

棒透了。

But as an agricultural researcher,

但我作為農業學家，

I know lots of additives work well in the lab,

我知道很多添加劑在實驗室很好用，

but not in real animals.

但在動物身上就不是如此。

But there was something different about seaweed

不過這在海藻 以及他們減少甲烷的方式上

and the way in which it reduced methane.

卻不大一樣。

So we thought we should test this in live animals.

所以我們想在動物身上實驗。

In collaboration with Joan Salwen,

我和瓊·薩爾文 (Joan Salwen)合作，

an entrepreneur,

他是個企業家，

and colleagues from James Cook University and CSIRO,

也是在詹姆士庫克大學 以及CSIRO的同事，

we decided to conduct a small experiment

我們決定先做個小實驗，

to determine the amount of seaweed we might need to use.

來決定海藻的使用量。

This was the first ever experiment in dairy cattle,

這是第一次在乳牛身上做的實驗，

and we had no idea how much to give them.

所以我們不知道該用多少。

So we started with about 60 grams per day,

所以我們從每天 60 公克開始，

going up to 250 grams.

逐步調整到 250 公克。

Mind you, this was mixed in with 25 kilograms of their feed.

提醒你一下， 這會混在他們 25 公斤重的飼料裡。

One of the graduate students I work with, Breanna Roque,

其中一個跟我共事的研究生 布雷安娜·羅克 (Breanna Roque)，

trapped their methane burps.

蒐集了牠們嗝出的甲烷。

(Laughter)

(笑聲)

In that first experiment,

第一次實驗結果，

the emissions were reduced by up to 67 percent.

甲烷排放減少了 67% 。

(Applause)

(掌聲)

And I thought at first,

我當下想說

the equipment must have malfunctioned, but it was real.

實驗器材一定故障了， 但並沒有。

But we are left with more questions than answers.

但是這個結果 帶給我們更多問題。

Would the microbes in the gut get used to it

腸道中的微生物 會不會習慣於這些海藻，

and start producing methane over time?

並隨著時間的推移 再次開始產生甲烷？

Would the seaweed be stable over a long period of time in storage?

海藻在長時間的儲存中 是否能保持穩定？

Would the taste be affected and the cows turn up their noses?

味道會不會受到影響， 牛會不會仰起鼻子？

Or would the seaweed affect the cows's health or milk production?

或者海藻會不會影響奶牛的健康 或產奶量？

So we teamed up again to conduct another trial.

所以我們再次聯手 進行了另一項試驗。

Over a five-month period,

在五個月的時間裡，

we saw the seaweed that was harvested three years prior

我們看到三年前收穫的海藻

reduce emissions by over 80 percent.

減少了 80% 以上的排放。

(Applause)

(掌聲)

Our colleagues in Australia,

我們在澳大利亞的同事，

they saw up to 98 percent reduction in a similar trial.

他們在一個類似的試驗中 看到了高達 98% 的減少。

That kind of reduction is simply staggering.

減少這麼多簡直是驚人的。

And in the graph,

而在圖表中，

you see methane emissions in three levels of intake.

你可以看到在三種程度的攝入量下 的甲烷排放量。

So the first line is for cattle with no seaweed,

所以第一行是 沒有攝入海藻的牛，

The second line is for cows

第二行是攝入了

that were supplemented with about 30 to 40 grams of seaweed.

大約 30 到 40 公克海藻的牛。

And the last one is for cows

而最後一種是為奶牛

supplemented with about 60 to 80 grams of seaweed.

補充了大約 60 至 80 公克的海藻。

As you can see, as you increase the amount of seaweed,

正如你所看到的， 當增加海藻的數量時，

you see a reduction in methane emissions.

甲烷排放量會減少。

We have also seen an improvement in bulking up

我們還看到， 肉牛的體型得到了改善，

of the beef cattle with no adverse health effects.

而且對健康沒有不良影響。

So it’s a win for the environment;

因此，這對環境來說是一個勝利；

it's a win for the farmers and consumers.

對農民和消費者來說也是一個勝利。

A panel of 112 people got to taste steak

一個由 112 人組成的小組

分別品嘗了來自飼餵了海藻的牛 和對照組牛製成的牛排。

made from steers offered seaweed and control.

And they did not detect any difference.

他們沒有發現任何差異。

We also did a nutritional quality of the meat,

我們還做了一個肉的營養質量檢測，

and we found no difference between animals that were offered seaweed

我們發現飼餵了海藻的牛 和對照組之間沒有區別。

and the control.

So how does it work?

那麼它是如何做到的呢？

Some seaweeds contain ingredients

一些海藻含有的成分

that directly inhibit microbes in the cow’s gut from forming methane

可以直接抑制奶牛腸道中的微生物 形成甲烷，

without interfering with food digestion.

而不干擾食物消化。

The amount of methane produced

甲烷的產生量取決於

is dependent on how much the animal is eating

動物的進食量和飲食中的內容。

and what's in the diet.

And as such,

因此，

previous efforts to reduce methane emissions

以前減少甲烷排放的努力

focused on changing their diets

集中在改變它們的飲食

or improving forage quality.

或提高飼料質量上。

And we do have potential solutions other than seaweed

而且，除了海藻之外， 我們確實有其他潛在的解決方案

to reduce methane emissions.

來減少甲烷排放。

We looked at additives to feed, such as 3-NOPs,

我們研究了飼料的添加劑， 如 3-NOPs，

reduce emissions by about 30 percent.

可減少約 30% 的排放。

Even garlic and citrus extract

即使是大蒜和柑橘提取物

can reduce methane burps by over 20 percent

也能減少 20% 以上的甲烷嗝，

without affecting animal health and productivity.

而不影響動物健康和生產力。

Now you may ask:

現在你可能會問：

Why not stop eating beef and drinking milk?

為什麼不停止吃牛肉和喝牛奶？

Audience member: Yeah!

聽眾：是的!

(Laughter)

（笑聲）

EK: That would be a good question.

EK：這是一個好問題。

So adopting a plant-based diet with supplements

在美國這樣的高收入國家，

may help shrink a person's carbon footprint

採用以植物為基礎的飲食 和補充食物

in high-income countries like the US.

可能有助於縮減一個人的碳足跡。

But, you know, a lot of people are not going to do that.

但是，你知道， 很多人是不會這麼做的。

And for the rest of the world,

而對於世界其他地區，

these foods are needed to provide key nutrients,

它們需要這些食物 來提供關鍵的營養物質，

such as vitamin B12 and vitamin A,

如維生素 B12 和維生素 A，

which are critical for brain function,

這對大腦功能、視力

for vision and immunity.

和免疫力至關重要。

These are found almost exclusively in beef and milk.

這些物質 幾乎只存在於牛肉和牛奶中。

In this graph, you see different countries

在這張圖中，你看到不同的國家

with their annual meat consumption per capita on the bar graph,

在條形圖上有他們每年的人均肉類消費，

and then you see the dots representing the stunting rate

然後你也能看到

in children below the age of five years old.

代表 5 歲以下兒童發育不良率的點。

And countries that have lower consumption of methane

而甲烷消費量較低的國家

are associated with higher incidence of stunting.

與發育不良的發生率更高的關連。

I know this firsthand.

我對這一點有切身體會。

Growing up in Eritrea,

在厄利垂亞長大的我，

I loved milk and meat when you could get it,

一旦有了牛奶和肉， 我就超開心，

which wasn't often.

但這並不經常有。

Even as a kid, I always wondered

即使在小時候，我也總好奇

how a cow, eating just grass, produces nutritious milk I love to drink.

一頭只吃草的奶牛是如何生產出 我喜歡喝的營養豐富的牛奶的。

And that wonder pushed me into a career to understand

這種好奇心促使我投身於了解和改善

and improve livestock production

畜牧業生產的事業中，

so that people in low-income countries do not suffer with stunting

從而使低收入國家的人們 不至於遭受發育不良

and other nutrient-deficiency diseases.

和其他營養缺乏症的困擾。

(Applause)

（掌聲）

So what now?

那麼現在呢？

We know seaweed can work.

我們知道海藻可以發揮作用。

But the cultivation of the specific seaweed has been a barrier.

但特定海藻的栽培 一直是一個障礙。

It's not so easy to farm asparagopsis taxiformis.

養殖紫杉狀海門冬 並不那麼容易。

But there are a number of efforts going on at the moment

但目前正在進行一系列努力，

to scale up production.

以擴大生產規模。

Blue Ocean Barns is growing seaweed in Hawaii already,

Blue Ocean Barns 已經在夏威夷種植海藻，

and they estimate that there will be enough production to feed all cattle

他們估計到 2030 年， 海藻的產量將

in the US by 2030.

足以餵養美國的所有牛。

All we need now is for governments to step up

我們現在需要的是 政府加強並促進

and facilitate the use of these methane-busting feed additives.

這些抑制甲烷添加劑的使用。

Cattle industries in some countries

一些國家的養牛業

have already committed to climate neutrality by 2050.

已經承諾到 2050 年 實現氣候中立化。

But if we can get these feed-additive innovations

但是，如果我們能讓這些 創新的飼料添加劑

into cow stomachs earlier,

更早地進入牛胃中，

we can cut methane burps significantly.

我們就能大大減少甲烷嗝。

Given that methane only lasts in the atmosphere for a decade or so,

鑑於甲烷在大氣中 只持續十年左右的時間，

we could even slow global warming in the short term.

我們甚至可以 在短期內減緩全球變暖。

Yes, we have a methane problem from cows,

是的，我們有 來自牛類養殖的甲烷問題，

but we may have seaweed and other solutions

但我們可能有海藻和其他方法 來解決這些甲烷嗝，

for these methane burps,

helping us provide meat and dairy while maintaining a safe climate.

幫助我們提供肉類和乳製品， 同時保持安全的氣候。

Thank you.

謝謝大家。

(Applause)

（掌聲）