西门子1136模块接线图:世界人口：现今已达70亿

世界人口

Now we are seven billion

现今有70亿

Persuading women to have fewer babies would help in some places. But it is no answer to scarce resources

说服女人少生孩子在某些地区行得通，但这并不是解决稀缺资源问题的答案。

Oct 22nd 2011 | from the print edition

2011年10月22日|来自印刷版

IN 1980 Julian Simon, an economist, and Paul Ehrlich, a biologist, made a bet. Mr Ehrlich, author of a bestselling book, called “The Population Bomb”, picked five metals—copper, chromium, nickel, tin and tungsten—and said their prices would rise in real terms over the following ten years. Mr Simon bet that prices would fall. The wager symbolised the dispute between Malthusians who thought a rising population would create an age of scarcity (and high prices) and those “Cornucopians”, such as Mr Simon, who thought markets would ensure plenty.

1980年，经济学家朱利安·西蒙与生物学家保尔·厄里奇打了个赌。畅销书《人口炸弹》的作者厄里奇先生挑选了五种金属--铜、铬、镍、锡和钨--并说它们的实际价格将在未来10年内上涨。西蒙先生则赌它们的价格会下跌。这个赌体现了认为增长的人口将会酿成一个（物资）匮乏（和高价物品横流）时代的马尔萨斯主义者和西蒙先生这样的认为市场物资充分的“资源丰饶主义者”的分歧。

Mr Simon won easily. Prices of all five metals fell in real terms. As the world economy boomed and population growth began to ebb in the 1990s, Malthusian pessimism retreated.

西蒙先生轻而易举地赢了。五种金属的实际价格全都无一例外地下跌了。上世纪九十年代，正当世界经济蓬勃发展时，人口增长的速度开始减缓，马尔萨斯主义者的悲观主义回退。

It is returning. On October 31st the UN will dub a newborn the world’s 7 billionth living person. The 6 billionth, Adnan Nevic, born in October 1999, will be only two weeks past his 12th birthday. If Messrs Simon and Ehrlich had ended their bet today, instead of in 1990, Mr Ehrlich would have won. What with high food prices, environmental degradation and faltering green policies, people are again worrying that the world is overcrowded. Some want restrictions to cut population growth and forestall ecological catastrophe. Are they right?

它卷土重来了。10月31日，联合国将会为世界上在世的第70亿人口授予称号。第60亿人，诞生于1999年10月埃德南·涅维克两周后即将迎来他的第12个生日。如果西蒙先生和厄里奇先生的赌现在截止，而不是在1990年，厄里奇先生就会赢。担心食品高价、环境衰退和艰难推行的环保政策的同时，人们又开始担心这个地球会过度拥挤。有些人希望动用法律削减人口增长并预先阻止这场生物学灾难。他们对么？

Lower fertility can be good for economic growth and society (see article). When the number of children a woman can expect to bear in her lifetime falls from high levels of three or more to a stable rate of two, a demographic change surges through the country for at least a generation. Children are scarcer, the elderly are not yet numerous, and the country has a bulge of working-age adults: the “demographic dividend”. If a country grabs this one-off chance for productivity gains and investment, economic growth can jump by as much as a third.

低密度（人口）对经济增长和社会都有好处（详见全文）。当一个女人可以承担的孩子数量从较多的3或3个以上降为稳定的2个，贯穿整个国家的人口统计学上的剧变至少持续了一代。儿童越来越少，老龄人口数并不庞大，成年劳力富余：（也就是所谓的）“人口红利”。如果一个国家抢占了这样的一次性的盈利和投资的机遇，经济将翻3番。

Less is more

过犹不及

However, the fall in fertility is already advanced in most of the world. Over 80% of humanity lives in countries where the fertility rate is either below three and falling, or already two or less. This is thanks not to government limits but to modernisation and individuals’ desire for small families. Whenever the state has pushed fertility down, the result has been a blight. China’s one-child policy is a violation of rights and a demographic disaster, upsetting the balance between the sexes and between generations. China has a bulge of working adults now, but will bear a heavy burden of retired people after 2050. It is a lurid example of the dangers of coercion.

然而，世界大部分地区的生育率（繁殖力）已经下降。逾80%的农村人的生育率不是少于3个并下跌就是已经是2个或更少。这并并不能归功于政府的限制，而应归功于现代化及个人对小家庭的渴望。每当一个国家强制下调繁殖力时，结果总是惨淡的。中国的独生子女政策是对权利的侵犯，也是一个人口（统计学上的）灾难，倾覆了性别及代间的平衡。中国成年劳力富余，但2050年后将会承受巨大的退休人员负担。这就是一个（体现）强制的危险性的恐怖案例。

Enthusiasts for population control say they do not want coercion. They think milder policies would help to save the environment and feed the world. As the World Bank points out, global food production will have to rise by about 70% between now and 2050 to feed 9 billion. But if the population stays flat, food production would have to rise by only a quarter.

人口控制的支持者们称他们并不想要强制政策。他们认为更加温和的政策能够帮助环境保护并能解决全球人口的吃饭问题。正如世界银行所指出的，从现在到2050年，全球粮食产量将会增长70%并能喂饱90亿人口。但如果人口持续低迷，食品产量将只能有25%的增长。

When Mr Simon won his bet he was able to say that rising population was not a problem: increased demand attracts investment, producing more. But this process only applies to things with a price; not if they are free, as are some of the most important global goods—a healthy atmosphere, fresh water, non-acidic oceans, furry wild animals. Perhaps, then, slower population growth would reduce the pressure on fragile environments and conserve unpriced resources?

当西蒙先生打赢了这个赌时，他就能说人口的增长不是问题：需求的增长吸引投资，产出更多。但是这只是对商品而言的；如果它们是免费的，正如某些全球最重要的物品--清新的空气、淡水、无酸的海洋及毛茸茸的野生动物。大概在那时，减缓的人口增长能够减轻施加在脆弱环境及保存无价资源的压力。

That idea is especially attractive when other forms of rationing—a carbon tax, water pricing—are struggling. Yet the populations that are rising fastest contribute very little to climate change. The poorest half of the world produces 7% of carbon emissions. The richest 7% produces half the carbon. So the problem lies in countries like China, America and Europe, which all have stable populations. Moderating fertility in Africa might boost the economy or help stressed local environments. But it would not solve global problems.

当其它形式的定量配给，如碳（排放）税、水价正在艰难执行之时，这个观点尤其地吸引人。但迅速增长的人口对气候变化影响甚微。世界上最穷的半球制造了7%的碳排放，最富有的7%制造了一半的碳（排放）。所以，问题的关键在于中国、美洲、欧洲之类拥有稳定人口的地区。非洲放缓的生育率也许会促进经济或是缓解当地紧张的环境。但这并不会解决全球性的问题。

There remains one last reason for supporting family planning: on some estimates, 200m women round the world—including a quarter of African women—want contraceptives and cannot get them. A quarter of pregnancies are unplanned. In our view, parents ought to decide how many children to bring into the world and when—not the state, or a church, or pushy grandparents. Note, though, that this is not an argument about the global environment but individual well-being. Moreover, family planning appears to do little directly to control the size of families: some studies have shown no impact at all; others only a modest extra one. Encouraging smaller families in the highest-fertility places would still be worth doing. It might boost the economy and reduce the pressure of population in some fragile places. But the benefits would probably be modest. And they would be no substitute for other sensible environmental policies, such as a carbon tax.

至少还有一个支持计划生育的理由：根据一些评估，全世界有2亿女性--包括¼的非洲女性--想要避孕套而不得。有¼的意外妊娠。在我们看来，应当由父母来决定将多少子女在何时带入这个世界，而不是由国家、教会或催促的祖父母们来决定。值得注意的是，这并不是在讨论全球环境，而是在说个人幸福。此外，计划生育似乎对家庭的大小的直接影响甚微：一些研究表明这根本就无所作为；另一些则证明这只是多此一举。在高生育率的地区鼓励小家庭仍然是值得的。在某些脆弱地区，它有可能推动经济并减少人口压力。但可能成效甚微。而且它们也不会取代例如碳（排放）税的其它的敏感环境政策。