End of history and the last woman

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這是我今年年初翻的文章，想說內容和現在不婚族的普遍頗有關的。來看看《經濟學人》去年做的研究吧！裡頭談到結婚率和女嬰出生率如何影響人類歷史，挺有趣的。


End of history and the last woman

Aug 22nd 2011, 15:02 by The Economist online

How long do countries have until their populations disappear?

 As The Economist reports this week, many women in the richer parts of Asia have gone on “marriage strike”, preferring the single life to the marital yoke. That is one reason why their fertility rates have fallen. And they are not alone. In 83 countries and territories around the world, according to the United Nations, women will not have enough daughters to replace themselves, unless fertility rates rise. In Hong Kong, for example, a cohort of 1,000 women would be expected to give birth to just 547 daughters, at today’s fertility rates. (That gives Hong Kong a “net reproduction rate” of just 0.547, in the language of demographers.) If nothing changed, those 547 daughters would be succeeded by just 299 daughters of their own, and so on. At that rate, according to some back-of-the-envelope calculations by The Economist, it would take about 25 generations for Hong Kong’s female population to shrink from 3.75m to just one. Given that Hong Kong’s average age of childbearing is 31.4 years, it could expect to give birth to its last woman in the year 2798. (That is some time after its neighbour, Macau, which has a higher reproduction rate, but a much smaller population.) By the same unflinching logic, Japan, Germany,Russia, Italy and Spain will not see out the next millennium. Even China, which has a recorded history stretching back at least 3,700 years, has only about 1,500 years left—if present trends continued unbroken. 

最後一位女人終結人類歷史

滅絕一國人口需要多久？

本週《經濟學人》談到，亞洲富裕地區多數女性正進行「婚姻罷工」，偏愛單身、討厭婚姻束縛。這些地區生育率低迷，理由之一在於此。但是，上述情形不只見於亞洲。聯合國表示，世上有83個國家或屬地，其女性將無法孕育足數的女兒來接手傳宗接代的任務，除非生育率提高。以香港為例，依目前的生育率，每1000名婦女預期產下547個女兒(用人口統計學家的術語來說，香港的淨生殖率為0.547)。如果條件不變，這547個女兒只會有299個女嬰接手；如此，代代衰減。《經濟學人》依此比率粗略估算，只要25代，香港女性人口將萎縮到3.75男：1女。假設香港婦女平均產齡為31.4歲，那麼在西元2798年香港只生下唯一的女嬰，也是最後一個(比起生育率較高、人口相對少很多的澳門，還要晚了些)。同理，再過一千年，日本、德國、俄羅斯、義大利、西班牙的人口數都將歸零。如果生育率未見起色，即便是歷史能追溯到3700年前的中國，也只能再撐1500年。