Not Seeker, specifically, I mean humans in general.

並不是特別指 Seeker 的錯，一般來說，我是指全人類。

We're digging up and burning sources of carbon that otherwise would have been locked

我們正在挖掘和燃燒碳源，否則碳源會鎖在地球內部，

away within the Earth, adding it to our atmosphere and driving average global temperatures up.

增加到大氣層中會導致全球平均溫度上升。

So why don't we take the carbon from the air, and push it somewhere else?

那麼，為何我們不從空氣中取出碳，然後把它推到別處呢？

That's the idea behind Negative Emission Technologies, or NETs.

這就是負排放技術 (NETs) 背後的想法。

They're one possible tool to stop climate change, but they aren't the silver bullet.

它們可能是阻止氣候變化的一種工具，但並不是萬靈丹。

It's tempting to think that if we develop a way to scrub the air of CO2 we won't have to cut down our emissions so much.

一般很容易認為，如果開發出清除空氣中二氧化碳的方法，就不必減少那麼多排放。

No lifestyle change, no big shift in energy infrastructure, just some quick fix that keeps this climate change thing from getting out of hand.

生活方式不用改變，能源基礎設施不用大轉變，用某些快速解決方案，讓氣候變化的問題不會失控。

Unfortunately while that's theoretically possible it's very far from practical.

可惜的是，雖然理論上可行，但離實際運用還很遠。

At the start of 2018 the European Academies Science Advisory Council released a report

2018 年初，歐盟科學顧問委員會發表一份報告，

on how feasible NETs are for slowing or reversing the effects of atmospheric carbon dioxide and their conclusion is… not good.

針對 NETs 能否減緩或徹底改變大氣中二氧化碳的可行性，他們的結論是......不太行。

First it helps to understand why plucking CO2 from thin air isn't as easy as it sounds.

首先，它有助於理解為何從稀薄空氣中抽出二氧化碳，並不像聽起來那麼簡單。

As of 2013 we were adding an estimated 40 billion tons of CO2 to the air annually.

從 2013 年起，我們每年在空氣中增加約 400 億噸的二氧化碳。

While that's a lot of CO2, it's not very concentrated; there are only about 400 CO2 molecules per million molecules that make up our air.

雖然二氧化碳的量很多，但並沒有很集中；每百萬分子中，約只有 400 個二氧化碳分子構成我們的空氣。

So if you want to just neutralize the stuff we're putting out each year, you're going to have to churn through a lot of air.

因此，如果想要中和我們每年排出的東西，就必須流失大量的空氣。

Jennifer Wilcox, an assistant professor at Stanford University, imagines what she calls a synthetic forest.

珍妮弗．威爾考克斯是史丹佛大學的助理教授，設想出人造森林的主意。

Sounds like cool funky neon trees but really it's more a 200 meter wall of fans pushing air through liquid with chemicals that capture carbon dioxide.

聽起來像是很酷又時髦的霓虹燈樹，但實際上是個 200 公尺的壁扇，推動空氣穿過液體時，化學物質會捕獲二氧化碳。

The chemical is then separated from the CO2 using high heat, allowing it to go back and capture more carbon.

之後使用高溫將化學物質與二氧化碳分離，讓化學物質回流並捕獲更多碳。

What's left behind is high-purity CO2 that's easier to liquify or repurpose.

留下高純度二氧化碳，更容易液化或重新利用。

Now you may have noticed this process isn't passive, you need to put energy into it.

你現在可能注意到這過程不是被動的，你需要將能量投入其中。

Wilcox estimates that to remove a million tons of CO2 a year,

威爾考克斯估計，每年要減少 100 萬噸二氧化碳，

you'd need a dedicated power plant putting out anywhere from 300 to 500 megawatts.

需要一個專用發電廠，發電量在 300 到 500 百萬瓦之間。

So to balance out that 40 billion tons we're emitting annually, that works out to 40,000 additional power plants.

因此，為了要平衡每年排放的 400 億噸二氧化碳，發電廠將增加額外 40,000 座。

And that's assuming you use carbon neutral power.

而這還是假設你用碳中和來計算。

If you use a coal plant, you emit more than you extract.

如果使用的是煤電廠，排放量就會超過提取量。

A synthetic forest isn't the only possible negative emission technology.

人造森林不是負排放技術唯一的可能。

We could go au naturale and plant more forests.

我們可以用自然的方式並種植更多森林。

Let the trees do the work.

讓樹木來完成工作。

Except planting new forests is hard and we're already deforesting what currently exists.

除了種植新的森林很難外，我們還大量砍伐現存的森林。

Really it'd be better to get that under control first.

先把這問題控制住比較實在。

Another alternative is sprinkling iron into the ocean, stimulating photosynthetic plankton to absorb more CO2.

另一種選擇是將鐵灑入海洋，刺激會行光合作用的浮游生物，吸收更多二氧化碳。

But that process is kind of like unleashing a tiger and hoping it takes care of your gorilla problem.

但這過程有點像放出老虎，希望牠能解決大猩猩的問題。

We could try making a carbon capturing mineral like magnesite in a lab.

我們可以嘗試在實驗室中製造礦物來捕獲碳，如菱鎂礦。

The mineral forms when magnesium is introduced to carbonic acid, a molecule that results when CO2 and water react.

碳酸與元素鎂結合形成礦物，碳酸是二氧化碳和水反應時產生的分子。

In August of 2018 scientists discovered how to make it artificially in just 72 days,

2018 年 8 月，科學家發現如何在 72 天人為製造出菱鎂礦，

as opposed to the hundreds of thousands of years it takes to form naturally.

而不是花數十萬年自然形成。

Now we just need to make 80 billion tons of the stuff every year and we're set.

我們現在每年只需生產 800 億噸的東西，我們就搞定了。

All of these issues led the European Academies Science Advisory Council to conclude that betting on NETs alone is not the answer.

這些問題導致歐盟科學顧問委員會得出一個結論，就是僅僅賭在 NETs 上並不是正解。

We can't keep emitting at the rate we are now and hope some future carbon capture wonder tech will turn the tide.

我們不能以現在的速度繼續排放，又希望未來碳捕獲技術能奇蹟似地扭轉局面。

The goal is still to cut current emissions as drastically as possible.

目標仍是盡可能大量減少現在的排放量。

In the meantime we can still develop negative emission technologies.

同時間，我們還可以發展負排放技術。

Just because they can't stop climate change alone doesn't mean they can't help.

只因為單靠負排放技術無法阻止氣候變遷，但並不表示它們沒有幫不上忙。

But humans need to scale back our carbon emission so NETs don't have to counter 40 billion tons of CO2 every year.

但人類需要縮減碳排放量，這樣 NETs 每年就不必抵銷 400 億噸的二氧化碳。

While you're here subscribe for more videos, and check out Marens video about new solar technology powered by bacteria.

在你訂閱看到更多影片的同時，來看看 Marens 的影片，了解由細菌驅動的新太陽能技術。

While CO2 levels are at 400 parts per million today, until 1950 CO2 hadn't risen above 300 parts per million for over 400 thousand years.

雖然二氧化碳含量目前為百萬分之 400，但直到 1950 年，二氧化碳濃度在 40 多萬年中，從未超過百萬分之 300。

Thanks for watching and I'll see you next time on Seeker!

謝謝觀看，下次在 Seeker 的影片見！