地球的力量 第2集 大氣(23)溫室氣體

Nobody knows quite how the Spanish overcame thisproblem

沒人知道西班牙移民如何征服了這個(gè)困難

but it's probably no more complicated than havingchildren with the locals.

可能是西班牙人和當(dāng)?shù)厝私Y(jié)婚生子

Even Andean peoples wouldn't be able to live permanently above 5,000 metres.

甚至安第斯人也無法在五千米環(huán)境生活

Higher than this and human reproduction is impossible.

高于這一海拔人類難以生育

In other words, oxygen sets a limit on the very existence of our species.

換句話說，氧氣對于我們的物種存在起很大限制

So life created oxygen and, in turn,

所以說，生命創(chuàng)造氧氣，反過來

oxygen has dramatically extended the possibilities for life.

氧氣戲劇性的又是生命的必需

And you might think that for us

也許你會認(rèn)為大氣層里

there's no more important gas in the atmosphere.

沒有對我們有用的重要?dú)怏w了

But you 'd be wrong.

那你就錯(cuò)了

There are other gases that are every bit as important

還有其他氣體對于我們在地球生存

for our survival on the planet.

有重要作用

These are the greenhouse gases, like carbon dioxide,

有溫室氣體，比如二氧化碳

that, as we've seen, are pumped out from volcanoes.

如我們所見，從火山中噴發(fā)

Without these gases, the average temperature of the planet

沒有這些氣體，地球的平均溫度

would fall to nearly 27 degrees below freezing.

會降到零下27度

But now we're releasing extra carbon dioxide into the atmosphere

但是我們現(xiàn)在排放了過量的二氧化碳到大氣中

by burning carbon-based fossil fuels like coal and oil and gas.

因?yàn)槿紵蓟V物燃料，比如煤礦，石油，天然氣