地球的力量 第3集 冰川(8)冰河世紀(jì)
這是個(gè)陌生和新奇的島嶼和山脈 人類從未見過
We may take it for granted that snow and ice arevery much part of our world
我們把冰和雪視為世界當(dāng)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凍的風(fēng)景
but in fact, nothing could be further from the truth.
但是，實(shí)際上，事實(shí)并非如此
As far as Earth is concerned, ice is pretty unusual.
當(dāng)?shù)厍虮谎芯恳詠?，冰就是非常特別的
For most of our planet's long history, about 90% of it.
我們地球漫長(zhǎng)的歷史中有90%的時(shí)間
there's been virtually no ice at all.
是一點(diǎn)冰都沒有的
Even the dinosaurs that hung around for 200 million years
甚至在恐龍遍地的兩億年前
never saw anything like this.
也沒見過這一景象
Our current era is actually an unusual time in Earth's history.
我們處于一個(gè)非常時(shí)段
It's called an ice age,
所謂的冰河世紀(jì)
an era when ice sheets covered large areas of the planet.
當(dāng)冰川覆蓋大片土地時(shí)
It began around three million years ago.
大約三百萬年前開始
when the continents of North and South America collided.
南北美洲大陸沖撞
The result 3 warm ocean current that flowed around the equator was cut off.
結(jié)果，三條沿著赤道流動(dòng)的海洋暖流被切斷
so now the warm water travelled north.
所以這暖流現(xiàn)在流向北方
Today we know this current as the Gulf Stream.
就是我們今天熟悉的墨西哥灣流
