評論
打印
Narrator: Listen to part of a lecture in an environmental science class.
請聽環境科學課上的部分內容。
Professor: Now, over the next few weeks, we're gonna focus on carbon and its role in what's known as the "greenhouse effect".
教授：在接下來的幾個周，我們會關注碳，以及它在"溫室效應"中所起的作用。
Everyone knows what that it, right? But let's make sure anyway. Yes, Karlie?
每個人都知道那是什么，對吧？不過不管怎樣，我們還是確定一下吧。Karlie，請說。
Student: The greenhouse effect is when gases in Earth's atmosphere act like the glass in a greenhouse or a hothouse.
學生：溫室效應是指地球大氣層中的氣體起著像溫室的玻璃一樣的作用。
They trap in heart which warms up the earth.
它們會把熱量困住，而這就讓地球變暖了。
Professor: Gases like?
教授：哪些氣體呢？
Students: Uh, water vapor? Carbon dioxide?
學生：水蒸氣？二氧化碳？
Professor: Right. Carbon dioxide, we hear a lot about carbon these days, no?
教授：沒錯，二氧化碳，我們最近經常聽到碳，不是嗎？
Carbon emissions, carbon burning, leaving a carbon footprint.
碳排放、碳燃燒、留下碳足跡。
So it'd be easy to assume that any form of carbon burning is necessarily a bad thing.
所以一個人很容易會以為任何形式的碳燃燒都一定是一件壞事。
But the fact is: it's not quite that simple.
但事實是：這遠沒有那么簡單。
So we're gonna focus today on difference between good, bad and well, the, not so bad, the potentially okay carbon burning.
所以，今天我們會集中討論一下好的、壞的、不那么壞的、可能沒問題的碳燃燒之間的區別。
OK.Good carbon burning, well, we all have a personal stake in this because burning carbon is the basis of life.
好的，首先是好的碳燃燒，我們所有人在這里面都有份，因為碳燃燒是生命的基礎。
We wouldn't be here if we ourselves weren't burning carbon, basically, all living things burn carbon to survive.
如果我們自己沒有在燒炭，我們就不會站在這里了，基本上，所有活著的生物都需要燒碳來生存。
Usually this happens at the cellular level and what's burned is carbon in the form of sugars, glucose.
這通常發生在細胞的層次，燃燒的是糖、葡萄糖形式的碳。
Oxygen gets chemically combined with sugars in our cells and the energy produced from that reaction is then used to power the cells.
氧氣會以化學的方式在我們的細胞中和糖結合，這種行為產生的能量接著會被用來給細胞提供力量。
So just by breathing you could say we are all guilty of carbon emission and contribute to the amount of carbon in the atmosphere.
可以說僅僅通過呼吸我們所有人都有排放碳的罪過，并且增加了大氣中的碳含量。
Um, another thing about atmospheric carbon: it keeps us from freezing.
另一個關于大氣中的碳的事情是：它能保護我們不被凍死。
Because without carbon and other greenhouse gases, our planet would be the same temperature as outer space, around four degrees above absolute zero.
因為沒有碳和其他溫室氣體，我們星球的溫度會和外太空一樣，大約在絕對零度以上四度左右。
And there's nothing going on at that temperature, no possibility of life of any sort, so without atmospheric carbon, life couldn't exist on Earth.
在那種溫度之下，沒有任何事情能夠得以進行，任何形式的生命都沒有存在的可能性，所以沒有了大氣中的碳，地球上就不會存在生命。
Now, another thing to remember is that carbon is always being removed from the atmosphere.
要記住的另一件事是，碳經常都被從大氣中清除了。
It gets used up, largely it is consumed by plant life through photosynthesis.
它會被耗盡，很大一部分都是被植物通過光合作用消耗掉了。
Also, it dissolves in the oceans or gets stored deep in the ocean.
它還會溶解在海洋中，或者被存儲在深海中。
You have shellfish that use the CO2 dissolved in the water to make carbonate shells and when they die, they fall to the ocean floor and the carbon gets sequestered down there.
貝類會用溶解在水中的二氧化碳做碳化的殼，當它們死后會掉落在海床上，而碳就被隔離在那下面了。
