the rigours of life in the polar regions.

极地生活的艰苦。

There was a period of excessive warmth which melted some of the polar ice.

有段时期温度过高，融化了极地的部分冰层。

the ill-fated polar explorers.

运气不佳的极地探险家。

The nomads' lifestyle was the polar opposite of collectivization.

游牧民的生活方式同集体化的生活方式完全相反。