As populations shrink around the world, so might armed conflicts

Across the globe, countries are undergoing a profound demographic transformation: widespread and likely irreversible population aging. Driven by a combination of low fertility rates and longer life expectancies, this shift has led to a growing proportion of citizens aged 65 and older, and with it, a steady rise in the median age of entire populations.

While population aging is typically seen as a burden—slowing economic growth and straining public resources—it may also carry an overlooked international benefit: a reduced likelihood of war. In a world increasingly marked by demographic decline, the twenty-first century may become not only the “age of depopulation” but also one of greater peace.

This conclusion may seem counterintuitive given the ongoing wars in Africa, Europe, and the Middle East. Yet research suggests that as nations age, they become less willing and able to initiate or sustain military conflict. Aging governments must devote increasing attention and resources to their elderly populations, while aging societies tend to exhibit a stronger preference for peace. As a result, older societies may simply become less tolerant of the costs and consequences of war.

Foreign Affairs has published findings that reinforce this view, revealing that the likelihood of a country engaging in war is closely tied to the age structure of its population. Nations with younger populations are statistically far more prone to conflict, whereas older societies show a marked reluctance to initiate hostilities. This trend, already visible in recent years, will only intensify as population aging accelerates.

Back in 1950, only about 5% of the global population was aged 65 or older. By 2021, that figure had nearly doubled. Even if fertility rates were to stabilize—a highly unlikely scenario—the United Nations projects that this figure will more than triple by 2050. Many aging societies are also shrinking in overall population size, further reinforcing this shift.

Although conflict has surged since 2012—what some analysts call a "global explosion of violent conflict"—the majority of these wars have been driven by youthful states. From 2012 to 2023, countries initiating military conflicts had populations where only about 5% were aged 65 or older—roughly half the global average in 2024. This suggests that demographically youthful societies continue to fuel most of the world’s violence, while older states increasingly abstain from such behaviour.

Market economics, public spending and manpower

One of the main reasons for this is economic. An aging population significantly hinders economic growth by reducing the number of working-age individuals (15–64), slowing productivity, and dampening consumer demand. In key regions, these demographic shifts are dramatic: between 2020 and 2050, Europe’s working-age population is projected to decline by 17%, East Asia’s by 24%, Japan’s by 28%, China’s by 23%, Russia’s by 19%, and Germany’s by 17%.

As the article recalls, aging also diminishes the productivity of a nation’s workforce. People in their 40s tend to be the most economically active—benefiting from a mix of experience, health, and adaptability.

As this vital cohort shrinks, countries will find it harder to sustain productivity growth. For instance, from 2020 to 2050, Russia’s share of workers aged 40–49 will fall by 10%, Japan’s by 15%, and China’s by 18%.

Even the adoption of transformative technologies like artificial intelligence may not be enough to reverse these productivity declines. Japan’s experience during the 1990s "Lost Decade" underscores this. Despite the IT boom, Japan’s productivity gains were modest, largely due to its accelerating aging crisis.

The decline in consumption further weakens economic dynamism. People in their 40s tend to spend the most, stimulating demand. As their share falls and the proportion of retirees—who typically spend less—increases, economic momentum slows. This has major implications for military spending.

Governments facing surging costs related to pensions, healthcare, and long-term elder care—projected to reach about 25% of GDP in many developed countries by 2050—will face hard choices. Although military budgets do not necessarily have to shrink, they may come under pressure as funds are reallocated. Many nations also spend heavily on programs aimed at boosting fertility, though with limited success. With so many fiscal demands, defence spending becomes an increasingly attractive area to cut.

The piece sheds light on another peace-promoting effect of aging, namely the shrinking of the military-age population. By 2050, East Asia will have nearly 48 million fewer people aged 18 to 23—a 42% drop. Europe will have eight million fewer (down 17%), and Latin America nearly nine million fewer (a 13% reduction). Simply put, it will become much harder to find enough young adults to serve in the armed forces.

This shortage forces militaries to make tough decisions. Relaxing recruitment standards may compromise quality. Offering higher pay to attract candidates, as Russia has during its war in Ukraine, raises per-soldier costs—potentially crowding out other military spending like weapons procurement or maintenance. If the quality of a military declines, the odds of victory decrease, making governments less willing to go to war.

Though some may look to technology as a substitute for manpower, many military operations—such as counterinsurgency and territory control—remain labour-intensive. As fertility continues to fall, the personnel needed for these missions will be harder to find.

By Nazrin Sadigova