地球的力量 第1集 火山(19)二氧化碳的重要性

Today we think carbon dioxide as a dangerous gas,

如今我們認為二氧化碳是危險的氣體

causing havoc through climate change.

它改變氣候并因而引發(fā)浩劫。

but actually, carbon dioxide has always been vital to our planet

不過事實上，二氧化碳對地球而言，一直是至關(guān)重要的

because it traps heat in the atmosphere that would otherwise be lost to space.

二氧化碳有助于留住大氣層內(nèi)的熱能 否則這些熱量將散失到太空中。

To see just how critical carbon dioxide is to Earth,

為了理解二氧化碳對地球的重要性

take a look at our near neighbors.

看一下地球鄰居的情況。

Mars is a frozen wasteland with an average temperature of minus 60 degree.

火星是一片冰凍荒原 平均為零下60度。

that is because, its atmosphere doesn't have enough carbon dioxide to keep it warm.

原因是火星大氣層沒有足夠二氧化碳來保暖

At the other extreme,

金星處在另一個極端

is hot enough to melt lead,not simply because it's a bit coser to the Sun,

其表面溫度高得足夠融化鉛 原因并不只是與太陽的距離更近

but because Venus has an atmosphere with thousands times more carbon dioxide than Earth.

也是因為金星大氣中的二氧化碳含量為地球的數(shù)千倍