温室气体

Nobody knows quite how the Spanish overcame this problem

没人知道西班牙移民如何征服了这个困难

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

可能是西班牙人和当地人结婚生子

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

甚至安第斯人也无法在五千米环境生活

Higher than this and human reproduction is impossible.

高于这一海拔人类难以生育

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

换句话说，氧气对于我们的物种存在起很大限制

So life created oxygen and, in turn,

所以说，生命创造氧气，反过来

oxygen has dramatically extended the possibilities for life.

氧气戏剧性的又是生命的必需

And you might think that for us

也许你会认为大气层里

there's no more important gas in the atmosphere.

没有对我们有用的重要气体了

But you 'd be wrong.

那你就错了

There are other gases that are every bit as important

还有其他气体对于我们在地球生存

for our survival on the planet.

有重要作用

These are the greenhouse gases, like carbon dioxide,

有温室气体，比如二氧化碳

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

如我们所见，从火山中喷发

Without these gases, the average temperature of the planet

没有这些气体，地球的平均温度

would fall to nearly 27 degrees below freezing.

会降到零下27度

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

但是我们现在排放了过量的二氧化碳到大气中

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

因为燃烧碳基矿物燃料，比如煤矿，石油，天然气

重点讲解

1、complicate

使难以理解；使复杂化

What complicates the issue is the burden of history.

历史的重负使问题复杂化了。

The day's events, he said, would only complicate the task of the peacekeeping forces.

他说白天发生的事件只会使维和部队的任务更为复杂。

2、pump out

大量生产（或提供）

Japanese companies have been pumping out plenty of innovative products.

日本公司一直在生产大量富有创意的产品。

World Service Television is pumping out 24-hour news to 38 countries in Asia.

英国广播公司世界电视台正24小时不间断地向38个亚洲国家播出新闻。

（流行音乐等）响亮地奏出，喧闹地传出

Teenage disco music pumped out at every station.

每一站都喧闹地播放着十几岁少年所喜爱的劲爆迪斯科音乐。

3、dramatically

突如其来的;急剧的;引人注目的

A fifth year of drought is expected to have dramatic effects on the California economy.

第五年遭受旱灾预计会对加利福尼亚的经济产生巨大的影响。

This policy has led to a dramatic increase in our prison populations.

这项政策已经让我们监狱的囚犯人数激增。

激动人心的;引人注目的;令人印象深刻的

He witnessed many dramatic escapes as people jumped from as high as the fourth floor.

他目睹了许多人从五层高的楼上跳下来逃生的惊险场面。

Their arrival was dramatic and exciting.

他们的到来令人激动不已，难以忘怀。

戏剧的;有关戏剧的;戏剧学的

a dramatic arts major in college.

大学里戏剧艺术专业的学生

I had no thoughts of making a dramatic film. I was working in documentary.

我没想过要拍一部剧情片，我正在拍一部纪录片。