Scientists believe that the entire world beyond Africa was populated from descendants of these two hundred individuals.
科学家认为非洲以外的男女老幼,全都是这两百人的后代,
Over time our ancestors multiply and spread out;
久而久之,我们的祖先越来越多,
to India, onto Asia and into Europe.
并扩散至印度、亚洲与欧洲。
But while humans head north, a giant wall of ice travels south.
然而人类往北走,一块巨大的冰墙却往南走,
Europe, 40,000 years ago.
欧洲,40000年前。
Homo sapiens arrive, only to find a world that's quickly changing.
智人来到这里,却发现世界变得实在太快了。
It should be the height of summer, but it's getting colder.
这时应是盛夏,天气却越来越冷。
The plants are frostbitten, and the rivers are frozen.
植物都被冻伤,河流也结了冰。
Natural changes in the Earth's orbit, CO2 levels, and the flow of warm water around the planet conspire to lower the Earth's temperature.
地球运行轨道的自然变化,二氧化碳浓度,与各地温水的流动,一齐使地球温度下降。
The Earth, and its inhabitants, enter an ice age.
地球与地球居民进入冰河时期,
Glaciers as high as skyscrapers creep over the northern hemisphere about a foot every day,
跟摩天大楼一样高的冰河,以每天30公分的速度覆盖北半球,
Slow, and powerful, they sculpt the landscape, gouging out great depressions.
它们用缓慢而强大的力量雕塑沿途经过的地表,挖出深深的洼地,
The planet will never look the same again.
地球样貌彻底改变,
Now, around twenty thousand years ago, they grind to a halt.
两万年前冰河突然停止移动。