Earth has been blessed with just the right balance ofstability and the occasional catastrophe.

地球被赋予了适宜的稳定 还有偶尔的灾难

Too many catastrophes and life never gets a chanceto develop.

太多的灾难，生命没有机会产生

Too few, and life gets stuck in a rut.

太少的灾难，生命被困在定例中

It's taken four and a half billion years to turn the Earth from a barren rock

花费了45亿年，地球从荒芜的岩石

into the world we see today.It's been a remarkable journey.

变成我们今天看到的世界 这是一个了不起的过程

But now the planet's facing perhaps its greatest challenge.

但是现在地球也许面临着最大的挑战

Humans.Just look at Earth from space.

现在有一股新的力量在威胁这个独一无二的星球 人类本身

At night, our lights mark out our domination of the world.

晚上，我们的光显示出我们统治着地球

By burning fossil fuels like coal and gas,

通过燃烧化石燃料比如煤和天然气

we've changed the very composition of the atmosphere,and with it, the climate.

我们改变了大气层的组成 结果提高了温度