Throughout Earth's history

翻开地球的历史

as carbon dioxide levels in the atmosphere havechanged,

大气层二氧化碳浓度有所变化

so has the temperature of the whole planet.

使得整个地球的温度

In fact, it's now becoming clear

事实上，现在逐渐了解

that even relatively small changes in carbon dioxide

甚至是细微的二氧化碳浓度变化

could begin a chain reaction.

也会导致连锁反应

And this would lead to unexpectedly large changes in our climate.

这会使得我们的气候产生难以预计的巨变

To find out what this might mean for our future, I'm off to Siberia.

为了这对于我们的未来意味着什么，我前往西伯利亚

This is one of the remotest and coldest regions on the planet,

这是地球上最遥远和寒冷的地方

and yet hidden in this frozen ground is the potential for a climate disaster.

目前有一个潜在的气候灾祸在这片冰原下

It's called methane,

被称为甲烷

and it's a far more powerful greenhouse gas than carbon dioxide.

这是比二氧化碳要强得多的温室气体

And that's what I'm looking for.

那正是我找寻的