It's a strange and unfamiliar world of islands andmountains that's never been seen by humans.

这是个陌生和新奇的岛屿和山脉 人类从未见过

We may take it for granted that snow and ice arevery much part of our world

我们把冰和雪视为世界当然的一部分

and that glaciers and ice sheets seem to be a permanent feature of the landscape

冰川和冰原是永久不解冻的风景

but in fact, nothing could be further from the truth.

但是，实际上，事实并非如此

As far as Earth is concerned, ice is pretty unusual.

当地球被研究以来，冰就是非常特别的

For most of our planet's long history, about 90% of it.

我们地球漫长的历史中有90%的时间

there's been virtually no ice at all.

是一点冰都没有的

Even the dinosaurs that hung around for 200 million years

甚至在恐龙遍地的两亿年前

never saw anything like this.

也没见过这一景象

Our current era is actually an unusual time in Earth's history.

我们处于一个非常时段

It's called an ice age,

所谓的冰河世纪

an era when ice sheets covered large areas of the planet.

当冰川覆盖大片土地时

It began around three million years ago.

大约三百万年前开始

when the continents of North and South America collided.

南北美洲大陆冲撞

The result 3 warm ocean current that flowed around the equator was cut off.

结果，三条沿着赤道流动的海洋暖流被切断

so now the warm water travelled north.

所以这暖流现在流向北方

Today we know this current as the Gulf Stream.

就是我们今天熟悉的墨西哥湾流