接著進化成直立人
who was the first to make sophisticated stone tools.
直立猿人是我們首先造出精密石器的祖先
But what caused these rapid changes has alwaysbeen a bit of a mystery.
石器的出現(xiàn)是偉大的巨變至今仍有一些迷題尚未解開It now seems that theytie in with the two greatest advances of the ice sheets.
現(xiàn)在的研究顯示他們與北冰原的兩個最劇烈的變化有聯(lián)系
Each time the ice advanced,
一旦冰層面積擴展
more of the Sun's energy was reflected from the planet.
更多的太陽能被反射進空間
This contributed to more extreme climatic conditions around the world.
導致世界許多區(qū)域出現(xiàn)極端氣候
In East Africa, home to our ancestors,
在非洲東部,我們祖先的家鄉(xiāng)
the climate became unstable and unpredictable.
氣候變得混亂和不可預(yù)知
In this fast-changing world, those who adapted best thrived.
在這種變化無常的世界里,誰能夠快速適應(yīng)誰才能存活
Both big brains and new weapons gave our ancestors an edge.
大容量的頭腦以及先進的工具使我們的祖先擁有了優(yōu)勢
Eventually, out of the climatic turmoil modern humans began to emerge.
最終,當氣候穩(wěn)定,現(xiàn)代人類出現(xiàn)了
If it wasn't for the recent ice age
如果不是冰河時代
helping to drive climate change in East Africa,
改變了非洲東部的氣候
we might not be here at all.
我們將不會出現(xiàn)在這里
So what does the future hold for the planet's ice,
那么冰層未來是怎樣的?
now that the Earth's climate is warming?
地球又是否正在變暖?
A good place to find out is Greenland.
格陵蘭是個尋找這個答案的好地方