The vast majority of the world’s countries are experiencing a demographic revolution: dramatic, sustained, and likely irreversible population aging. A combination of low fertility levels and high life expectancies has led to a significant increase in the percentage of people 65 and older and with it, a steady rise in the median age of their populations. In 1950, around five percent of the world’s population was 65 or older. By 2021, that number had nearly doubled. Even if fertility rates stop declining and remain where they were in 2022—an unlikely development—the United Nations forecasts that by 2050 that percentage will have more than tripled. Many of these states are not just aging; they are becoming smaller as a result. More than 40 countries have shrinking populations because of low fertility levels. By 2050, nearly 90 countries will have fewer citizens at the end of each year than they did at the beginning
全球大部分国家都在经历一场人口大变革：人口老龄化，而且是那种很夸张、持续不断、估计还改不了的。生育率低加上人均寿命长，导致 65 岁以上的老年人比例大幅增加，人口的平均年龄也一直在涨。1950 年的时候，全球大概只有 5%的人是 65 岁及以上的。到了 2021 年，这个数字差不多翻倍了。就算生育率不再下降，就停在 2022 年的水平（这可能性不大），联合国预测到 2050 年，这个比例会涨到原来的三倍多。
很多国家不光是老龄化，人口还在缩水。因为生育率低，已经有 40 多个国家人口在减少了。到 2050 年，差不多有 90 个国家，年底的人口会比年初还少。
As many analysts have pointed out, the aging of a population slows economic growth and necessitates new and greater public spending on the welfare of elderly citizens. But it also has an important unrecognized international benefit: aging significantly reduces the likelihood of war between states. The twenty-first century, widely predicted to be an “age of depopulation,” may also turn out to be a more peaceful one.
很多分析师都说了，人口老龄化会拖慢经济增长，而且还得花更多钱在老年人福利上。但它还有一个没啥人注意到的国际好处：老龄化大大降低了国家之间打仗的可能性。这个二十一世纪，大家都说会是“人口减少的时代”，说不定也会是个更和平的时代。
The idea that international conflict will in future decades ebb may appear counterintuitive, given the large number of wars in Africa, Europe, and the Middle East during the first quarter of the century. But as countries grow older, governments will be forced to attend to their aging populations and contend with a shrinking pool of resources. All the while, as leaders and citizens age, studies indicate that they will be more likely to express a preference for peace. These factors will combine to create societies less capable and tolerant of waging war.
虽然 21 世纪头二十年非洲、欧洲和中东战事不断，但国际冲突在未来几十年会减少这个想法听起来可能有点反常。不过，随着国家越来越“年长”，政府将被迫关注老龄化人口，并应对日益枯竭的资源。同时，研究表明，随着领导人和民众年龄增长，他们会更倾向于和平。这些因素加在一起，会让社会越来越没能力也没意愿打仗。
Although there are certainly exceptions, the tendency to fight wars, in other words, is stronger in countries with younger populations. The coming wave of old and shrinking populations will fundamentally reshape geopolitics. In at least one way, that transformation will be for the better.
虽然肯定有例外，但人口年轻化的国家打仗的倾向会更强。老龄化和人口萎缩的浪潮将从根本上重塑地缘政治。至少在某一方面，这种转变会是好事。
WORLD AT WAR? 世界要打仗了？
In 2023, Emma Beals and Peter Salisbury wrote in Foreign Affairs about the “global explosion of violent conflict” since 2012. Indeed, according to data collected by the Uppsala Conflict Data Program and the Peace Research Institute Oslo, the number of state-led military conflicts nearly doubled in the decade between 2012 and 2022.
2023 年，Emma Beals 和 Peter Salisbury 在《外交事务》杂志上写道，自 2012 年以来，“暴力冲突在全球范围内爆发”。确实，根据乌普萨拉冲突数据项目和奥斯陆和平研究所收集的数据，在 2012 年至 2022 年这十年间，国家主导的军事冲突数量几乎翻了一番。
But these statistics fail to show that interstate violence is largely restricted to demographically young countries. In every year from 2012 to 2023, the average percentage of people ages 65 and older for all of the principal states initiating violent conflict stood at five, roughly half the average of that of all the countries in the world in 2024.
但是这些数据没说，国家间的暴力冲突主要集中在那些人口结构年轻的国家。从 2012 年到 2023 年，每年发起暴力冲突的主要国家里，65 岁及以上人口的平均占比都只有 5%，这差不多是 2024 年全球所有国家 65 岁及以上人口平均占比的一半。
Demographically older states have thus already demonstrated a reduced tendency to engage in violent conflict. Statistical analyses show that these countries are significantly less likely to initiate military hostilities than are younger ones. What appears to be a universal trend toward war is in reality predominantly powered by the aggressiveness of demographically youthful states.This could help explain the high prevalence of war and conflict across the African continent, which has some of the youngest populations in the world.
人口结构偏老龄化的国家，在暴力冲突这块儿已经表现出没那么爱掺和的趋势了。统计分析显示，这些国家主动挑起军事冲突的可能性，比那些年轻的国家要低得多。所以，那种看起来像是普遍存在的“战争趋势”，其实主要是那些人口结构年轻化的国家在搞事情。这也能解释为啥非洲大陆战争冲突那么多，毕竟那里的年轻人是全球最年轻的群体之一。
MAKE LESS, NOT WAR 少搞点事，别打仗
A central way that an aging population reduces resources potentially available for war is by significantly slowing economic growth. By shrinking the number of workers in a society, slowing productivity, and reducing domestic consumption, aging makes countries less economically dynamic—and less capable of funding wars.
老龄化社会削减战争资源的一个主要方式就是大幅拖慢经济增长。随着社会劳动力减少、生产力下降以及国内消费萎缩，老龄化会让国家经济活力减弱，也就更难支撑战争开销了。
Reductions in working-age populations (defined as people between the ages of 15 and 64) will transform the composition of societies across the globe. Europe’s working-age population will shrink by roughly 17 percent by 2050 from 2020 levels; East Asia’s will shrink by 24 percent. Between 2020 and 2050, Japan’s working-age population is expected to shrink by 28 percent, China’s by 23 percent, Russia’s by 19 percent, and Germany’s by 17 percent.
劳动年龄人口（指 15 至 64 岁人群）的减少将改变全球社会的构成。到 2050 年，欧洲的劳动年龄人口将比 2020 年减少约 17%；东亚则会减少 24%。在 2020 年至 2050 年间，日本的劳动年龄人口预计将减少 28%，中国减少 23%，俄罗斯减少 19%，德国减少 17%。
Population aging hinders productivity growth by increasing the median age of the labor force. An old workforce is a less productive one. People tend to be most productive in their 40s, when they have more knowledge, experience, and resources than younger workers and more energy and better health than older workers. People in this age cohort are also more willing than older individuals to acquire new skills and knowledge, to engage in high-risk but high-reward ventures, and to relocate for job opportunities. As many cross-national studies have found, the size of this cohort relative to older and younger workers is a key determinant of countries’ overall productivity growth. When the share of 40-to-49-year-olds rises, overall productivity gets a boost. When it falls, overall productivity suffers.
人口老龄化会推高劳动力的平均年龄，从而拖累生产率增长。老龄化劳动力生产力确实会下降。一般来说，人到 40 多岁时，知识、经验和资源都比年轻人多，同时精力也比老年人充沛、身体也更健康，是生产力最强的时期。这个年龄段的人也比年纪更大的人更愿意学习新技能、新知识，更敢于尝试高风险高回报的事情，也更愿意为了工作机会而搬家。很多跨国研究都发现，这个年龄段的人占劳动力总数的比例，是决定一个国家整体生产率增长的关键因素。40 到 49 岁这个年龄段的人占比上升时，整体生产率就会提升；反之，占比下降时，整体生产率就会受影响。
This is bad news for the economic prospects of aging countries. Among workers, the share of 40-to-49-year-olds relative to 30-to-39-year-olds and those 50 and older will plummet in many countries over the course of the twenty-first century. In Russia, this crucial share for productivity growth will shrink by ten percent from 2020 to 2050; in Japan by 15 percent; and in China by 18 percent.
这对于老龄化国家的经济前景来说，简直是坏消息。在劳动人口里，四五十岁的人相对于三四十岁以及五十岁以上的人的比例，在 21 世纪的很多国家都会大幅下降。在俄罗斯，这个对生产力增长至关重要的比例，从 2020 年到 2050 年会下降 10%；日本是 15%；中国更是高达 18%。
An old workforce is a less productive one.
A major technological advance, such as the widespread adoption of artificial intelligence, could potentially help reverse these trends. But even the AI revolution is not guaranteed to arrest the economic slowdown. Japan’s so-called Lost Decade illustrates this point. The information technology boom of the mid-1990s gave some countries a major productivity gain, one that was similar in scale to what some economists predict for the AI revolution. Yet Japan was not among the beneficiaries. Its total factor productivity, a measure of the economic value of innovation and technological advancement, grew by only one percent from 1995 to 2005, one-quarter as much as it did in the preceding decade. The acceleration of Japan’s aging crisis during this period was central to this slowing productivity growth. Compared to the number of people ages 30 to 39 and 50 to 64, Japan’s highly productive 40-to-49-year-old cohort peaked in 1991, then plummeted by 29 percent between 1995 and 2005. The information technology revolution thus may have helped Japan’s productivity tread water in the face of rapid population aging, but because the country’s workforce lacked the optimal age structure, the IT boom did not result in a significant increase in overall economic dynamism. There is reason to expect that countries with similarly aging populations will face comparable problems in the AI revolution.
Population aging will hinder economic expansion on the demand side, as well. Robust domestic consumption accounts for roughly two-thirds of economic activity in most high-income countries. The problem for aging states is that the size of the population that tends to spend the most (people in or close to their 40s) is shrinking, while the proportion of the population that tends to spend significantly less (those 65 years and older) is ballooning.
Weak consumption due to the effects of aging has, for example, contributed to China’s slumping housing market. The cohort most likely to purchase homes (people around 30 years of age) has plummeted by 30 percent since 2020. As a result, demand has crashed, straining household wealth, the government’s ability to finance itself through taxation, and China’s economy at large.
Slowdowns in economic growth will likely lead to disputes over increasingly scarce resources in aging countries. But they will also reduce the ability of those countries to engage in war with another country. According to the economists Mark Harrison and Nikolaus Wolf, the number of militarized disputes that states have initiated has historically risen apace with GDP and GDP per capita expansion. As a country’s economic power increases, the relative cost of its achieving its international goals decreases. Consequently, as the economic power of a state grows, it may be more willing to seek costly change, even by waging war. If increased growth tends to make state aggression more likely, lower growth caused by aging will tend to make such aggression less likely.
GUNS OR CANES?
As the number of seniors skyrockets, government obligations for the welfare of the elderly, chiefly pensions and health care, have ballooned. Analysts predict that many developed countries’ public spending on pensions, health care, and long-term care for the elderly is on track to hit roughly 25 percent of GDP by 2050. These trends are already affecting aging democracies with deep social safety nets and historically less generous authoritarian regimes alike. In 2009, China spent 4.4 percent of its GDP on pensions and health care. This figure grew to 8 percent in 2020 and is projected to climb to over ten percent in 2030 and to roughly 20 percent in 2050.
Governments spend billions to deal with not only with the consequences of aging populations but also with their causes. The Organization for Economic Cooperation and Development (OECD)’s member states spend an average of 2.3 percent of GDP on child and family programs, many of which are designed to boost fertility (although few meaningfully do so).
The rapid-aging demographics are also indirectly responsible for government spending on domestic security and welfare programs for the non-elderly because they powerfully contribute to many of the key sources of rising discontent in the developed world, including slowing economic growth, austerity, and growing ethnic and anti-immigrant tensions, as dominant groups fear their demographic demise. In response to rising unrest, many governments attempt to repress disgruntled groups or appease them through social programs. China, for example, quadrupled its spending on policing and domestic surveillance between 2007 and 2020; by 2020, these expenditures exceeded military spending. Japan’s spending on labor and employment support, poverty relief, and social protection (excluding old age and health-care spending) increased from 0.5 to 3.7 percent of GDP between 1990 and 2020.
As countries spend more to address the causes and consequences of aging, other spending, including on the military, will likely be crowded out as budgets come under increasing strain. Although governments need not necessarily cut military expenditures to help pay for rising elderly welfare costs, they will have strong incentives to do so. Although military spending can increase economic growth by employing underutilized labor, stimulating aggregate demand, and funding research that ultimately helps civilian industries, as research by J. Paul Dunne and Nan Tian has shown, it is more likely to harm long-run growth by reducing expenditures on more productive investments and by contributing to higher levels of debt. Coupled with slow economic growth rates and tight budgetary constraints created by high levels of elderly welfare expenditures, military spending may emerge as an attractive pool of resources to reallocate.
Statistical analysis of democratic and authoritarian countries indicates that once government spending on social welfare, including for the elderly, crosses 25 percent as a proportion of a country’s budget, the likelihood that the country will initiate a militarized dispute declines significantly. Many aged countries are either on the verge of or have already crossed this threshold. Spending on old age, unemployment, and income maintenance (and related expenditures) as a share of general government spending averaged nearly 21 percent in OECD countries in 2021. Given that these expenditures will only grow, these countries will have strong budgetary incentives to avoid initiating military hostilities.
A FEW GOOD MEN
A final way in which aging will make the world more peaceful is by shrinking the size of the prime military-age cohort. In 2050, East Asia will have nearly 48 million fewer 18- to 23-year-olds than in 2020, a 42 percent reduction; Latin America will have nearly nine million fewer, a 13 percent reduction; and Europe will have over eight million fewer, a 17 percent reduction. Put simply, aging countries will find it harder to marshal the manpower needed to fight protracted, bloody wars.
With fewer prime-age recruits available, militaries will be forced to make difficult decisions about the size and quality of their fighting forces. If they do not boost recruitment rates when the number of potential soldiers is greatly reduced, they are unlikely to meet their personnel targets. However, if militaries increase recruitment rates by relaxing the requirements for age, health, and physical and mental abilities, they will sacrifice quality for quantity. They may also try to increase recruitment rates by increasing salaries and benefits, as Russia has in its war in Ukraine. But unless total military budgets increase, rising per-soldier labor costs will crowd out other areas of military spending, including for weapons development, procurement, and maintenance. If states are less likely to win wars because they are worse at fighting them, they are likely to be less inclined to start them.
Aging states with shrinking recruitment pools have consistently had trouble meeting their military personnel goals despite frequently relaxing standards and increasing compensation. From 2000 to 2021, Japan on average filled just 93 percent of its authorized personnel positions. Despite lowering standards for service and dramatically increasing soldier compensation after the country’s 18-to-23-year-old male cohort began declining in 2009, China’s military continues to experience a shortage of skilled soldiers. Russia in the 2010s consistently failed to meet its recruitment targets for both conscripted and contracted soldiers. Although these personnel problems did not prevent Russia from invading Ukraine in 2022, a shortage of high-quality soldiers has hampered the country’s fighting abilities, making it harder to win the war. Russia continues to fight in Ukraine, but its manpower struggles could help deter other aged states from waging wars in the future.
Militaries could try to work around shrinking military-age cohorts by substituting technology for personnel. The revolution in artificial intelligence, the recent successes of unmanned drone swarms, and the possibility of “killer robots” may make the large-scale substitution of technology for military labor increasingly attractive. But because many military missions will continue to be labor-intensive, there are limits to militaries’ ability to substitute technology for labor. Counter-insurgency and wars that require holding enemy territory will continue to require well-staffed militaries. Falling fertility rates make it harder to meet this need.
Moreover, shifting to capital-intensive warfare to offset diminishing prime-age soldier populations will likely require the recruitment of higher-quality personnel to service, use, and complement the more sophisticated equipment. A 2022 report issued by the Congressional Research Service, for example, concluded that unmanned aircraft systems in the U.S. military are likely to require an equal or greater number of military personnel than their crewed counterparts. Finding these highly capable soldiers will be difficult in a world of aging populations.
PROTEST GENERATION
Although a slower pace of economic growth and a decline in available military resources are likely to lead to less capable militaries in aging countries and, as a result, more peaceful international relations, the opposite is possible. Shrinking military capabilities could encourage leaders who see a closing window of opportunity to use force to achieve national objectives. But they are likely to face countervailing pressure because aging populations tend to prefer peace. Decades of survey data show that people tend to become more pacific and opposed to the use of force as they age. A 2006 Pew Research Center analysis of surveys conducted in the United States from the early 1960s to the mid-2000s concludes that “there is a generation gap over U.S. military interventions,” with elderly Americans consistently exhibiting “the greatest wariness about using military force.” Jessica Chen Weiss has similarly concluded, based on surveys from the 2010s, that older Chinese citizens were significantly less likely than younger ones both to believe that China relies “too little” on military power and to view the U.S. military presence in East Asia as a “major threat.” They were also less willing than younger individuals to “send troops and not shirk a fight.”
Aging populations are also likely to have a greater aversion to their country’s soldiers’ dying in war. Military casualties and the deaths of young people who have not yet had children may heighten fears that war will permanently weaken an already depopulating country.
Mounting public opposition to military deaths and casualties is particularly important in democracies because it can jeopardize leaders’ electoral support. But as populations age, it will also matter to authoritarian regimes, which may worry that wartime losses could incite domestic backlash. By 2030, for example, close to half of China’s prime military-age cohort will be only children. Low fertility in China has already resulted in the existence of hundreds of thousands of shidu (bereavement) parents, who lost the only child the government permitted them to have under the old one-child system. Throughout the 2010s, these parents demonstrated annually in front of the headquarters of the National Health and Family Planning Commission in Beijing to demand that the government provide some of the support that they would have expected to receive from their deceased offspring. The more Chinese leaders have reason to believe that bereaved single-child parents are likely to protest, the more cautious they may be about initiating a war.
PEACE THROUGH AGE
Population aging will not completely eradicate war, as Russia’s invasion of Ukraine demonstrates. But it will reduce the ability of governments to fight or widespread support for them. All aging states, regardless of their revisionist ambitions or reliance on military aggression, will have no choice but to face squarely the effects of this demographic revolution. Demography goes a long way in determining the economically and militarily possible. Aging, then, is likely to become a powerful force for peace that has never before existed.
