No need to panic as baby boomers mature
The two world wars of the 20th century had enduring but different effects on population. The conflict of 1914-18 killed and maimed young men in appalling numbers. Except in Russia, there were fewer casualties in 1939-45, and they were widely distributed among the civilian as well as military population. The first world war was followed by an abnormally low birth rate: rapid economic recovery after the second world war led to an unusually high birth rate.
And so, in 1980, the cohort of potential retirees - those aged between 55 and 64 and therefore born between 1916 and 1925 - was relatively small. Conversely, the 15-24 age group, the new workers born between 1956 and 1965, was relatively large. In Britain, France, Germany and even in the US, there were almost twice as many new workers as potential retirees.
The US was more successful at creating jobs for new workers, but wage earners gained little from the resulting economic growth, and inequality in income distribution widened considerably. Continental Europe resisted this trend: instead, youth unemployment rose and there was an explosion of what, in last week's column, I called "quasi- retirement". The official retirement age did not fall, but large numbers of older workers left the labour force, few with any intention of working again. These quasi-retired workers took advantage of benefits for sickness or disability until they reached normal pension age. Some were frustrated that their skills were no longer required. Others, with limited skills, welcomed the opportunity to escape dull jobs.
In 1980, there was little difference between France and the US in the proportion of working people aged 55-64. By 1990, a large gap had emerged in this age group: labour force participation was 38 per cent in France and 54 per cent in the US. The French experience was repeated across Europe, most of all in Germany where the ranks of the quasi-retired were swollen by reunification. This left many older workers in the east without hope of productive employment at wages comparable to their entitlement social benefits.
Perhaps, on balance, the more market-oriented American response was better. But the verdict is not obvious, and each continent experienced social tensions as a consequence of its choice. In any event, these are yesterday's issues, not today's. The cohort of new workers and the cohort of potential retirees are now both about 20 per cent of the working age population - pretty much the number that would be expected in a steady state. In Europe, the proportion of potential retirees still working stabilised in the early 1990s, and youth unemployment has been falling. In the US, the increase in wage inequality appeared to end in 1995 as the economy boomed.
The effect of these demographic fluctuations is not over yet. The baby boomers - the cohort of 1956-65 - will reach retirement age in the next two decades. If, like their predecessor generation in Europe, most stop work before retirement age, the costs will soon start to spiral. But this will probably not happen.
Metaphorically, even literally, there is always a queue of those hoping to leave employment and a queue of those hoping to join it. When - as in the 1980s - many are hoping to join and many are hoping to leave, participation rates tend to fall and so do the wages of people in work. We can opt for more of one and less of the other, but there is no avoiding this unpalatable choice. That was the dilemma of the 1980s; wages took the strain in the US and employment in Europe.
But when - as in the next decades - the queue of joiners is short and that of leavers long, we will face different options. With young workers in short supply, early retirement will no longer be readily available, and the tendency to greater wage inequality will be reduced.
Visions of apocalypse meet a deep-seated human need. The intellectual history of the last three centuries is full of mostly unfulfilled prophesies of doom. Future demography is a problem for the world economy. But before panic sets in, we should appreciate the extent to which that economy has absorbed demographic changes in the last two decades without anyone really noticing
面对“退休潮”莫恐惧
20世纪的两次世界大战均对人口产生了深远影响，但影响的方式完全不同。1914-18年的第一次大战中，战死、伤残的年轻人不计其数。除了俄罗斯以外，1939-45年的第二次世界大战的伤亡人数就少一些，而且伤亡者分布广，有军人也有平民。一战后，出生率进入了超常的低谷期；二战后，经济迅速复苏，导致出生率出现异乎寻常的高峰。
因此，在1980年，在55岁和64岁之间、生于1916年和1925年之间的潜在退休者，只是一个相对比较小的群体。相反，15-24岁年龄段、亦即1956-1965年之间出生的从业者，就是比较大的群体。在英国、法国、德国，甚至还有美国，新从业者的人数几乎都是潜在退休者的两倍。
在为新从业者创造就业机会方面，美国更为成功，但是在随后的经济繁荣期，工薪阶层获益甚少，收入分配不均大幅度增加。欧洲大陆却抵制住了这一倾向：相反，年轻人的失业率上升了，另外，我在上周专栏里所说的“准退休”正出现爆炸性增长。官方的退休年龄并没有下降，但是大量年龄较大的从业者离开了工作岗位，而且没有几个人想要重新就业。这些准退休的人还没有达到正常领取退休金年龄，但他们在利用病假或残疾等方面的福利。他们有些人为自己的技能得不到应用而沮丧，但其他人的技能有限，而准退休让他们终于可以摆脱乏味的工作，这种机会他们非常欢迎。
1980年，法国和美国55-64岁从业者的比例相差无几。到了1990年，这一年龄段的分布出现了重大差异：法国从业者比例为38%，而美国是54%。法国的经历在欧洲其它国家重演，特别是德国。德国统一造成了准退休者人数的急剧增长，德国东部一些上了年纪的从业者很难指望充分就业，即便能够充分就业，工资还达不到退休福利金水平。
美国的应对方法是以市场为导向，综合来看，或许这一方法更佳。但是这一判断也不是绝对的，两个大陆作出各自的选择，都造成了各自的社会压力。但无论如何，这都是过去的问题了，目前已不存在。现在，新就业者和潜在退休者人数各占就业人口20%，这基本上是一个稳定国家所应有的比例。上世纪90年代初期，欧洲仍在工作的潜在退休者的比例保持稳定，而青年失业率在下降。在美国，收入不均的上升趋势在1995年的经济繁荣期就终结了。
这些人口变动造成的影响还没有结束。婴儿潮一代(1956-1965年出生的人)在20年后将进入退休年龄。如果他们和上一代欧洲人一样，在达到退休年龄前离开岗位，成本不久就会大幅度上升。但这种情况大概不会出现。
总是有人在排队等候退休，同样也总是有人在排队等候就业，这既是比喻，也是实情。和80年代一样，有很多人等着就业，有很多人希望离开，所以就业率会下降，从业者的工资也会下降。我们可以在鱼与熊掌间做出选择，但是这种选择是根难啃的骨头，且无法避免。这曾经是80年代的矛盾。当时美国面临工资的压力，欧洲面临的是就业的压力。
接下来的几十年，等候就业者少，等候退休者多，我们就会相应地面临新的选择。由于青年就业者短缺，提前退休的难度会增加，收入差距扩大的趋势也会得到缓解。
启示录般的预言总是为了满足深层的人类需要。过去三个世纪以来，思想史上未曾实现的悲观预言比比皆是。未来的人口是世界经济面临的一个问题，但先不要惊慌。值得我们欣慰的是，经济的消化能力很强。过去二十年来，我们一不留神，经济就已经不声不响地消化了各种人口变动。
(back)Through the demographic window of opportunity
Thomas Malthus forever attached the word "dismal" to "economics". The argument of the 19th century sage that rising population would offset any tendency towards rising standards of living was as depressing as it has since proved incorrect. Malthus was not the first prophet to underestimate human ingenuity. He will not be the last.
Yet Malthus was right to believe that demography is always important. As this month's World Economic Outlook from the International Monetary Fund makes plain, demographic forces will drive the world economy in the decades ahead.* Three big things are now happening. First, fertility rates - the number of children produced by each woman - are falling rapidly almost everywhere. Second, life expectancy is also rising almost (though not quite) everywhere. Third, developing countries are well behind the advanced countries, with the poorest countries furthest behind of all.
As a result of these changes, annual world population growth fell from 1.8 per cent in 1950 to 1.2 per cent in 2000 and is forecast by the United Nations to reach just 0.3 per cent by 2050. The proportion of the world's population under 15 fell from 34 per cent in 1950 to 30 per cent in 2000, but is now forecast to reach 20 per cent by 2050. Average life expectancy jumped from 47 in 1950 to 65 in 2000 and is forecast to reach 74 by 2050. Consequently, the proportion of people over 65 rose from 5 per cent in 1950 to 7 per cent in 2000, and is forecast to reach 16 per cent by 2050. Finally, the countries we call "least developed" contained only 8 per cent of the global population in 1950, while the advanced countries contained 32 per cent. By 2000, these proportions had shifted to 11 and 20 per cent, respectively. By 2050, they are forecast to reach 19 and 14 per cent.
All forecasts are uncertain. Those of demographers are no exception. One uncertainty is over fertility rates. The UN assumes that the fertility rate of developing countries will fall from just above three children per woman in 2000 to two by 2050. Meanwhile, the fertility rate in advanced countries is forecast to rise modestly in the advanced countries to 1.85 children per woman, from 1.7 in 2000. The assumption then is that fertility rates will converge globally, towards the replacement rate.
On longevity, the big assumption is that life expectancies will continue to rise. Life expectancies in developing countries are forecast to reach 74 by 2050, up from 64 in 2000. Even in Africa, life expectancy is forecast to reach 63 by 2050, up from just 48 in 2000 (itself a fall from 50 in 1990). In advanced countries, too, life expectancies are forecast to rise further, to 83 in 2050, from 77 in 2000.
Changes in fertility would not make much of a difference to the scenarios until some decades hence, since the labour force of the next few decades is already born. What could make a difference much sooner would be a catastrophic spread of disease. If HIV/Aids, for example, were to attain a similar prevalence in the rest of the developing world to that now in southern Africa, the consequences could be devastating: in Botswana, a fifth of children below 17 years of age are orphans, while life expectancy fell from 65 in the early 1990s to 40 in 2002. If anything remotely similar were to happen in China or India, the tragedy would be beyond the imagination. But that seems almost inconceivable.
Assume, then, that the forecasts are broadly correct. There are three powerful economic implications. First, the dependency ratio will hardly change at the global level, but its composition will be transformed. Throughout the past, societies contained a host of children and few old people. This picture is now being reversed. The longer run implications are likely to be quite large.
Second, the effort to reduce the numbers and proportion of the world's population that lives in desperate poverty is a "Red Queen's race": the world has to run fast to stay still, as Lewis Carroll described in Through the Looking Glass. What is dragging the world backwards is Malthusianism in reverse: the greater a country's poverty, the faster population grows.
Finally, when fertility rates decline, there is a period when the proportion of the population of working age rises and the dependency ratio falls. Subsequently, however, the proportion of the population of working age will fall (see charts). This gives a window of economic opportunity. For Europe and Japan, it is now closing. For much of the developing world, notably China, it is open, but will soon close.
The IMF's analysis focuses on the economic impact of this demographic transition. As the proportion of the population in middle years reaches its peak, it notes, so should the overall national savings rate. Similarly, the higher the share of the population of working age, the higher the rate of investment. Fiscal positions should also improve. The overall result of this phase of the transition is higher growth. Then, as the dependency ratio rises, these effects go into reverse.
Given where countries are now in the transition, the impact on growth over the next half-century should vary from significantly negative in Japan and western Europe to modestly negative in the US, emerging Asia and Latin America and to positive in the Middle East and Africa (see chart). Whether the latter will exploit their opportunity is another question.
The period when the dependency ratio starts to rise once again and growth rates to fall is tricky to manage. This is particularly true if politicians were too generous with their promises on pensions and other age-related expenditures when growth was relatively rapid.
If reform is postponed too long, change may be hard to achieve in democracies. In the course of the next half century, the proportion of voters aged 50 and over will exceed half of the electorate in most of today's advanced countries (see chart). I have long believed that parents should be given votes on behalf of each of their minor children. This may now be an essential reform if the old are not to strangle their societies. It will not happen, alas.
Yet whatever the difficulties of the demographic transition, let us not forget the most important point. The challenges posed by ageing societies with declining populations are the result of huge successes: growing prosperity, women's increasing control over their reproduction and rising longevity. Malthus was wrong. Let us delight in that simple fact.
从人口趋势看世界经济
托马斯?马尔萨斯(Thomas Malthus)总是把“沉闷”(dismal)一词与“经济学”(economics)并列。这位19世纪的智者声称，人口日益增加将抵消生活水平提高的任何趋势。这一观点后来证明是错误的，这同论点本身一样令人沮丧。马尔萨斯不是第一个低估人类聪明才智的预言家，也不会是最后一个。
但马尔萨斯认为人口统计学总是很重要，这个观点是对的。正如国际货币基金组织(International Monetary Fund)在本月《世界经济展望》(World Economic Outlook)中所阐明的，在今后几十年里，人口的力量将推动世界经济增长。目前正在发生的有三件大事。第一，几乎每个地方的生育率(每个妇女生育孩子的数量)都在迅速下降。第二，几乎（但不完全是）每个地方的预期寿命也都在上升。第三，发展中国家正远远落后于发达国家，而最贫穷的国家最落后。
这些变化的一个结果是，世界人口的年增长率从1950年的1.8%降至2000年的1.2%，而且据联合国预测，到2050年将下降到仅有0.3%。15岁以下人口在世界人口中所占比例从1950年的34%降至2000年的30%，预测到2050年将降至20%。平均预期寿命从1950年的47岁猛升至2000年的65岁，预测2050年将达74岁。结果，65岁以上人口的比例从1950年的5%升至2000年的7%，预期2050年将达16%。最后，那些我们所谓“最不发达国家”在1950年时仅包含全球人口的8%，而发达国家包含了32%。而到2000年，这两个比例分别变成了11%和20%，预期到2050年将变成19%和14%。
所有的预测都是不确定的，人口学家的预测也不例外。一个不确定性是生育率。联合国假设，发展中国家的生育率将从2000年每个妇女生略多于三个孩子下降到2050年的两个。同时，预计发达国家的生育率将从2000年的1.7个温和升至1.85个。由此得出的假定是，全球各地的生育率将趋同，达到替换率（每个妇女生两个孩子）水平。
在寿命上，宏观假设是预期寿命将继续上升。预计到2050年，发展中国家的预期寿命将从2000年的64岁升至74岁。甚至在非洲，预计预期寿命也将从2000年仅48岁升至2050年的63岁（2000年已低于1990年的50岁）。在发达国家也一样，预计预期寿命将进一步上升，从2000年的77岁升至2050年的83岁。
由于今后几十年的劳动力已经出生，因此要到数十年之后，生育率的变化才会对人口面貌造成很大影响。若说有什么可能在短期内改变人口面貌，那将是疾病的灾难性蔓延……
例如，若在其他发展中国家，HIV/艾滋病达到与目前在非洲南部相似的流行程度，那么结果就有可能是灾难性的。在博茨瓦纳，17岁以下的孩子中有五分之一是孤儿，预期寿命从上世纪90年代初的65岁降至2002年的40岁。即使是中国或印度发生任何稍许类似的情况，那酿成的悲剧将是不可想象的。但这看来几乎是不可能的。
接下来，假设上述种种预测基本正确，那就会对经济产生三大影响。第一，全球抚养比率几乎不会改变，但其成分将转变。自古以来，各个社会一直包含大量儿童和极少数老年人，但这种局面正在颠倒。从更长远来看，影响可能会非常大。
第二，努力减少极度贫困人口的数量及其占世界人口的比例，这将是一场“打败红心皇后之赛”：世界不得不快速奔跑以求留在原地，正如刘易斯?卡罗尔(Lewis Carroll)在《爱丽丝漫游镜中世界》(Through the Looking Glass)中所描述的。要说现在是什么在拖累世界，那就是倒过来说的马尔萨斯人口论：一国越是贫穷，其人口增长越快。
