First, the bad news: Global fertility is falling fast. The aging populations of rich countries are relying on ever fewer workers to support their economy, dooming those younger generations to a future of higher taxes, higher debt, or later retirement—or all three. Birth rates in middle-income countries are also plummeting, putting their economic development at risk. Practically the only countries set to continue growing are desperately poor.
首先，坏消息：全球生育能力正在迅速下降。富裕国家的老龄化人口依靠更少的工人来支持他们的经济，注定了那些年轻一代的税收，更高的税收，更高的债务或以后的退休，或者这三个退休。中等收入国家的出生率也正在暴跌，使其经济发展处于危险之中。实际上，唯一要继续发展的国家迫切贫穷。
By about 2084, according to the gold-standard United Nations “World Population Prospects,” the global population will officially begin its decline. Rich countries will all have become like Japan, stagnant and aging. And the rest of the world will have become old before it ever got the chance to become rich.
根据金牌标准的联合国“世界人口前景”，到2084年，全球人口将正式开始下降。富裕的国家都将变得像日本，停滞不前和衰老。而且，世界其他地方才会变得悠久，然后才有机会富有。
Sorry, did I say “bad news”? That was actually the good news, based on estimates that turned out to be far too rosy. Every two years, the UN’s demographers revise their population projections, and for the past 10 years, they’ve always had to revise in the same direction: down. Next year, they’ll do so again. In reality, the worldwide population decline is set to begin decades ahead of their expectations. Because global fertility trends are much worse than they, and probably you, think.
抱歉，我说“坏消息”吗？实际上，这实际上是一个好消息，基于估计，事实证明太乐观了。联合国人口统计学家每两年都会修改他们的人口预测，在过去的十年中，他们一直必须朝着相同的方向进行修改：下降。明年，他们会再次这样做。实际上，全球人口下降将在他们的期望之前几十年开始。因为全球生育率趋势比他们和您可能会想到的要差得多。
Jesús Fernández-Villaverde, a University of Pennsylvania macroeconomist, studies how poor countries develop. This development usually happens alongside a fertility transition. As people move from rural areas to cities, their economic opportunities expand, and kids become less crucial as a source of agricultural labor. Women gain access to contraception and education. They go from having about six kids, on average, to two. Fernández-Villaverde calls this “the standard modernization story,” and he’s been teaching it for decades.
宾夕法尼亚大学宏观经济学家JesúsFernández-Villaverde研究了贫困国家的发展方式。这种发展通常与生育过渡一起发生。随着人们从农村地区迁移到城市，他们的经济机会不断扩大，并且孩子作为农业劳动的来源变得不那么重要。妇女获得避孕和教育。他们平均有大约六个孩子到两个。Fernández-Villaverde称此为“标准现代化故事”，他已经在教书了数十年。
Much of Fernández-Villaverde’s research focuses on Latin America, an economically middling region where one would expect middling fertility rates. In recent years, however, births in some Central and South American countries have plummeted to rates far lower than most rich countries’, in defiance of the standard modernization story. Each year, Fernández-Villaverde updates his data on Latin American birth rates, which he gathers from the countries’ official birth statistics, in preparation for a class he teaches about the region’s economic history. He first began noticing in 2019 that the UN was too optimistic, but only in the past few years did the discrepancies become downright alarming.
Fernández-Villaverde的大部分研究都集中在拉丁美洲，拉丁美洲是一个经济中等的地区，人们期望中等生育率。然而，近年来，在不违反标准现代化的故事的情况下，一些中美国家和南美国家的出生局势远低于大多数富裕国家的比率。每年，Fernández-Villaverde都会从国家正式出生统计数据中收集有关拉丁美洲的出生率的数据，以准备他教他的经济历史的课程。他在2019年首次开始注意到联合国太乐观了，但是在过去的几年中，差异才变得令人震惊。
For 2024, the UN had projected 701,000 births in Colombia; it had put the chance of the number of births being lower than 553,000 at only 2.5 percent. In the end, Colombia saw only 445,000 births in 2024. That translates to a fertility rate of 1.06 births per woman, down more than half from 2008. Chile’s is even lower: At current rates, 100 reproductive-age Chileans can expect to have 52 children and only 27 grandchildren. (Demographers generally consider a birth rate of about 2.1 to be “replacement level,” or the point at which a society doesn’t shrink from one generation to the next.)
2024年，联合国预计在哥伦比亚有701,000个出生。它使出生率低于553,000的机会仅为2.5％。最后，哥伦比亚在2024年只有445,000个出生。这意味着每位女性的生育率为1.06个出生，比2008年的生育率下降了一半以上。智利甚至较低：当前率，100个生殖时代的智利人可以期望有52个孩子，只有27个孙子。（人口统计学家通常认为大约2.1的出生率是“替代水平”，或者社会不会从一代人缩小到另一代。）
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The discrepancies were not limited to South America. In 2024, Poland’s births were also below the 2.5-percent probability cutoff, as were Estonia’s and Cuba’s and Azerbaijan’s and Sri Lanka’s and Egypt’s. These supposed outlier results aren’t outliers at all—the world is just not having as many babies as the UN had thought it would.
差异不仅限于南美。在2024年，波兰的出生也低于2.5％的概率临界值，爱沙尼亚和古巴和阿塞拜疆和斯里兰卡和埃及的诞生也低于2.5％的概率临界值。这些所谓的离群结果根本不是离群值，而世界没有像联合国想象的那样多的婴儿。
Digging into the UN’s model, Fernández-Villaverde found something even stranger. For nearly every low-fertility country, the UN projects either one of two outcomes: The fertility rate will flatten, or it will rise to a number somewhere between one and two births per woman—still below replacement level, but not quite as catastrophic. The United States is in the first category. Our fertility rate has fallen steadily since the Great Recession, from 2.1 to 1.6. One might therefore expect the decline to continue. But the UN projects that the U.S. birth rate will stay flat, not just this year but also in 2026 and 2030 and 2060 and 2090, never rising above 1.7 or dipping below 1.6.
挖掘联合国模特，费尔南德斯·维拉维德（Fernández-Villaverde）发现了一些陌生人。对于几乎每个低矮的国家，联合国预测的两个结果之一：生育率将会变平，或者将在每个女性一个和两个分娩之间的数字上升到一个替代水平以下，但不太灾难性。美国属于第一类。自大衰退以来，我们的生育率从2.1降至1.6。因此，人们可能预计下降会继续下去。但是，联合国预计，美国的出生率将不仅在今年，而且在2026年，2030年，2060年和2090年都保持平稳，从不增加1.7以上或低于1.6。
In the other category are countries such as Thailand, whose fertility rate has been falling for 72 years and has never stopped for longer than a single year. Nonetheless, there the UN projects a demographic miracle: Starting in two years, the country’s birth rate will begin to climb, first slowly and then a little more quickly, finishing out the century with a birth rate of 1.45, up from its projected 2024 low of 1.20.
另一类是泰国等国家，泰国的生育率已经下降了72年，并且从未停止使用超过一年的时间。尽管如此，联合国项目的一个人群奇迹：从两年来开始，该国的出生率将开始攀升，首先要慢慢，然后更快，然后以1.45的出生率为1.45，比预计的2024年低点为1.20。
Every part of that appears to be wrong. In reality, Thailand’s reported birth rate last year was 0.98, and preliminary 2025 data show the decline continuing. In a country the size of Thailand, the difference between the UN’s projection and the real fertility rate throughout the 21st century will amount to millions of people who will never be born.
每个部分似乎都错了。实际上，泰国去年的出生率为0.98，2025年初步数据显示下降持续。在一个泰国规模的国家中，联合国预测与21世纪的真正生育率之间的差异将达到数百万永远不会出生的人。
All in all, as Fernández-Villaverde recently explained at a research symposium in London, humanity won’t start to shrink in 2084. It will start to shrink in 2055, if not sooner.
总而言之，正如Fernández-Villaverde最近在伦敦的一项研究研讨会上解释的那样，人类不会在2084年开始收缩。它将在2055年开始缩小，即使不是很快。
“There are two types of people,” Alice Evans, a British professor who studies falling fertility around the world, posted on X after reading Fernández-Villaverde’s presentation: those “not bothered about demographics” and “those who’ve read Jesus’s slides.”
“有两种类型的人，”英国教授爱丽丝·埃文斯（Alice Evans）在阅读了费尔南德斯·维拉维德（Fernández-Villaverde）的演讲之后，在X上刊登了生育能力，他的演讲：那些“不为人口统计学的人打扰”和“那些读过耶稣幻灯片的人”。
The UN has a simple explanation for its optimistic projections: Fertility has rebounded in the past, so it will rebound again.
联合国对其乐观的预测有一个简单的解释：过去的生育能力已经反弹，因此它将再次反弹。
In Belarus, for example, the fertility rate in 1988 was at replacement level; it fell to an abysmal 1.22 only nine years later. But then it rebounded, all the way up to 1.73 by 2015. Australia’s birth rate fell to 1.7 in 2001, only to bounce back to 2.0 in 2008. France’s rate followed a similar trajectory during the same period, as did Italy’s and Sweden’s. “To the extent you think the ‘World Population Prospects’ are wrong, that is the extent to which you are saying, ‘This time is different,’” Lyman Stone, a Ph.D. student and birth-rate consultant, told me.
例如，在白俄罗斯，1988年的生育率处于替代水平。仅九年后，它跌至1.22个糟糕的1.22。但是随后它反弹，到2015年一直达到1.73。澳大利亚的出生率在2001年下降到1.7，只能在2008年反弹至2.0。法国的利率在同一时期的类似轨迹之后，与意大利和瑞典的轨迹相似。“在某种程度上，您认为'世界人口前景'是错误的，这就是您所说的‘这次是不同的，'” Lyman Stone，博士学位。学生和出生率顾问告诉我。
The thing is, this time really does look different. Birth rates in Australia and France and Italy and Sweden have now fallen to all-time lows (excluding during World War I, in France’s case). Belarus, a onetime redemption story, recorded a fertility rate of just 1.1 last year, lower than the lowest lows the country experienced in the 1990s. Deaths outnumbered births by nearly two to one. If a rebound is coming, there are no signs of it yet. Fernández-Villaverde estimates that the world is already below replacement fertility: The population is not just projected but guaranteed to shrink if things don’t change. That was not the case in the 1990s.
问题是，这次确实看起来确实不同了。澳大利亚，法国，意大利和瑞典的出生率现在已经跌至历史最低点（以法国为例，在第一次世界大战期间不包括）。白俄罗斯（Belarus）是一个曾经的救赎故事，去年的生育率仅为1.1，低于该国在1990年代经历的最低低点。死亡人数超过了近二比一世。如果反弹来了，那么还没有迹象。Fernández-Villaverde估计，世界已经低于替代生育能力：不仅预计人口，而且如果情况不变，则保证会缩小。在1990年代并非如此。
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The UN’s model hasn’t adjusted to the new normal. If a country has ever experienced a fertility increase (as Australia and France and Belarus have), then its birth rate is assumed to be stable. If a country has never experienced an increase, then the model assumes that it will at some point, once fertility gets low enough. In other words, the model assumes as its end state a stable and modest number of births. This is perhaps a reflection of humanistic optimism. “There is, at some point, a minimum social capacity to adapt and eventually at least address some of the concerns or challenges that exist in that country,” Patrick Gerland, the chief author of “World Population Prospects,” told me. “The people living in those countries don’t necessarily want their country to totally disappear.”
联合国的模型尚未适应新的常态。如果一个国家曾经经历过生育力的增加（如澳大利亚，法国和白俄罗斯所拥有的），则假定其出生率是稳定的。如果一个国家从未经历过增长，那么该模型假设一旦生育能力就足够低，则假设它会在某个时候。换句话说，该模型将其最终状态视为稳定且适度的出生。这也许是人文乐观的反映。“世界人口前景”的首席作者帕特里克·格兰德（Patrick Gerland）告诉我：“在某个时候，有一个最低的社会能力可以适应并最终解决该国存在的一些担忧或挑战。”“居住在这些国家的人们不一定希望自己的国家完全消失。”
To his point, the model comes with a hard-coded minimum: No country can ever be projected to have a fertility rate less than 0.5 children per woman. Like the rest of the model, this, too, might need to be revised. Macau (which the UN analyzes separately from mainland China) had a fertility rate of 1.2 a decade ago. Last year, it fell to 0.58, and it looks set to fall even further: In the first four months of 2025, births were down another 13 percent.
就他而言，该模型的最低限度为最低：预计每个女子的生育率少于0.5个孩子。像模型的其余部分一样，这也可能需要修改。澳门（联合国与中国大陆分开的分析）十年前的生育率为1.2。去年，它降至0.58，看起来将进一步跌落：在2025年的前四个月，出生又下降了13％。
If you’re not sure why this is all so alarming, consider Japan, the canonical example of the threat that low fertility poses to a country’s economic prospects. At its peak in 1994, the Japanese economy made up 18 percent of world GDP, but eventually, the country’s demographics caught up with it. Now Japan’s median age is 50 years old, and the country’s GDP makes up just 4 percent of the global economy. Measured per hours worked, Japan’s economic growth has always been strong, but at some point, you just don’t have enough workers.
如果您不确定为什么这么令人震惊，请考虑日本，这是低生育能力对一个国家经济前景构成的威胁的规范例子。在1994年的高峰期，日本经济占世界GDP的18％，但最终，该国的人口统计数据赶上了它。现在，日本的中位年龄为50岁，该国的GDP仅占全球经济的4％。日本经济增长的量度一直很强，但是在某些时候，您只是没有足够的工人。
The fertility rates that doomed the Japanese economy ranged from 1.3 to 1.5. So imagine what’s in store for modern-day Colombia (1.06) and Chile (1.03). How will they grow with so few workers? How will they ever become rich if each worker is expected to provide for so many elderly people? The overly optimistic UN estimates have obscured just how urgent these questions really are. Because if the birth rate continues to drop around the world at its current pace, economic growth and workers’ retirement prospects will go the way of those projections: adjusting every few years to a smaller, sadder, poorer future.
注定日本经济的生育率范围为1.3至1.5。因此，想象一下现代哥伦比亚（1.06）和智利（1.03）的商店。他们将如何与这么少的工人一起成长？如果期望每个工人提供这么多老年人，他们将如何变得富有？过于乐观的联合国估计掩盖了这些问题的真正紧迫性。因为如果出生率继续以目前的速度下降，那么经济增长和工人的退休前景将逐步了解这些预测：每隔几年调整每隔几年，将其调整为一个较小，悲伤，贫穷的未来。
