Sometime in the 1970s, most advanced economies crossed a quiet threshold. Fertility rates fell below 2.1 children per woman, the level required to keep a population stable, and never recovered.

Fifty years later, that threshold has become a fault line dividing the global economy into two distinct demographic worlds, one that’s shrinking, and one expanding, with consequences that neither side can navigate alone. They show up in labor shortages and a gradual shift in where the world’s economic weight is moving.

The Data Behind Population Decline

The numbers are well-documented. The average total fertility rate (TFR) across OECD countries fell from 3.3 children per woman in 1960 to just 1.5 in 2022 — well below the level needed for population stability without immigration.

South Korea recorded a TFR of 0.72 in 2023, and Italy and Spain stood at 1.2. Japan’s working-age population has declined sharply by 16% from its 1995 peak of 87.3 million to just 73.7 million in 2024. It’s projected to further decline by 31% from its 2023 levels by 2060.

The dependency ratio, or the number of elderly relative to working-age adults, tells the same story. In Japan, the old-age dependency ratio went from 21% in 1995 to 49% in 2024 and is projected to reach 74% by 2060, per OECD data. Across the OECD broadly, by 2060, old-age dependents per working-age person are set to rise by 67%. A Lancet study projects that by 2050, 155 of 204 countries will have fertility rates below replacement level, rising to 97% of countries by 2100.

Now, these aren’t speculative projections. The people who will be workers and retirees in 2040 are already born, and the structural direction has been largely set.

Economic Consequences in Developed Markets

An aging, shrinking population reshapes an economy through three compounding pressures.

Labor Supply Constraints

Japan already faces a labor shortage, and by 2040, it could be short of 11 million workers. Per an OECD report, the Bank of Japan’s Tankan survey findings also indicated widespread labor shortages, the country’s lowest in the last 30 years.

A shrinking working-age population limits labor force growth, which in turn constrains economic expansion. Even with productivity gains, fewer workers generally translate into lower potential output.

Fiscal Strain

In Japan, public debt is already elevated, exceeding 200% of GDP. Across the OECD, estimates suggest that without policy adjustments, aging-related spending will place sustained pressure on public finances through 2060.

Aging populations increase demand for pensions, healthcare, and social services while reducing the tax base that funds them. This creates structural budget challenges, particularly in countries with extensive social welfare systems.

The Slow Drag on Productivity

An IMF analysis estimated Japan’s economic growth will fall by around 0.8% per year over the next four decades due to demographic aging and shrinking. Without changes in policy, OECD modeling puts the GDP per capita growth slowdown across its membership at roughly 0.4 percentage points annually. That sounds modest until you compound it over several decades.

While aging workforces can retain experience and institutional knowledge, they may also see slower rates of innovation and labor mobility. Economies with fewer young workers may face challenges in adopting new technologies at scale.

Potential Policy Responses

Governments and businesses are already experimenting with responses:

• Automation and AI to offset labor shortages
• Extended working lives through higher retirement ages
• Pro-natalist policies, including childcare support and financial incentives
• Immigration policies designed to supplement domestic labor forces

However, none of these solutions is a complete substitute for a stable or growing population. Automation improves productivity but doesn’t fully replace human labor across all sectors. Immigration can help, but it’s often constrained by political and social considerations.

Growth in Developing Economies

In contrast, many developing regions, particularly Sub-Saharan Africa, are experiencing sustained population growth. Fertility rates in the region remain significantly higher than the global average. Additionally, the continent’s population is projected to grow substantially by 2050 and account for 22% of the global population, Agence Française de Développement reported.

Per the UN, five of the eight countries expected to account for more than half of all global population growth are African, specifically the Democratic Republic of the Congo, Egypt, Ethiopia, Nigeria, and Tanzania.

This trend creates the potential for a demographic dividend, which is a period in which the working-age population grows faster than dependents, enabling higher productivity, savings, and economic growth.

However, this outcome isn’t automatic. To realize a demographic dividend, countries must meet several conditions:

• Access to quality education to build human capital
• Job creation at scale to absorb new labor market entrants
• Healthcare improvements to sustain a productive workforce
• Stable governance and institutions to support investment

Without these conditions, rapid population growth isn’t sustainable and instead can strain infrastructure, public services, and employment markets, potentially leading to underemployment or instability.

The divergence between developed and developing economies is therefore not simply about population size, but about the ability to convert demographic trends into real economic outcomes.

Capital, Infrastructure, and Global Rebalancing

As demographic patterns shift, capital allocation is likely to shift with them.

Historically, developed markets have attracted the majority of global investment due to stable institutions, mature financial systems, and predictable returns. However, as growth slows in these regions, investors are increasingly looking toward higher-growth markets.

Emerging economies with expanding populations represent long-term opportunities, particularly in sectors such as:

• Infrastructure (transport, energy, digital networks)
• Urban development
• Education and workforce training
• Technology and connectivity

Yet these opportunities come with execution challenges. Infrastructure gaps, regulatory complexity, and financing constraints can limit progress.

This is where coordination becomes critical. Aligning government priorities with private sector capabilities can accelerate development and reduce risk.

Delivering this shift will depend less on capital availability and more on execution, specifically, the ability to coordinate governments, investors, and operators around large-scale infrastructure projects.

Migration as a Pressure Valve

Migration is the most direct link between two labor markets moving in opposite directions. Aging economies are short of workers. Growing ones are producing more labor than their domestic markets can absorb. On paper, the supply and demand line up cleanly, but in practice, the dynamics are much more complex.

Economic Benefits

For destination countries, migration can help alleviate labor shortages, support economic growth, and stabilize demographic decline. For origin countries, remittances can provide significant income flows and support local economies.

Political and Social Constraints

Despite economic benefits, migration remains politically sensitive in many developed economies. Public concerns around integration, labor competition, and cultural change often shape policy decisions.

Skill Shortages and Mismatch

Migration isn’t always aligned with labor market needs. High-skill shortages may persist even when migration flows increase, while low-skill labor markets may become saturated.

As a result, migration functions as a partial, rather than complete, solution to demographic imbalance.

Historical Parallels

Demographic change driving economic restructuring isn’t new. The post-war baby boom gave Europe and North America a long labor and consumer dividend. East Asia’s demographic transition (Japan, South Korea, and China) helped fuel the region’s economic ascent from the 1960s through the 2010s.

What’s different now is the scale and timing. Previous transitions were mostly national or regional. The current divergence is happening across nearly all developed economies simultaneously, while Africa’s potential dividend is still decades from its turning point. Aging is occurring simultaneously across multiple developed economies, and technological change is accelerating, thus altering labor demand patterns.

Managing a divide this large, inside an economic system this interconnected, has no real historical precedent to draw from.

Two Possible Futures

The long-term outcome will depend on how effectively global systems adapt.

In one scenario, demographic complementarity is successfully leveraged. Capital flows toward regions with young, growing workforces (high-growth regions). Developing economies build the infrastructure and institutions needed to put the labor to productive use. Migration is structured in ways that work for both sides, and growth becomes more geographically distributed.

In another, coordination may fall short. Developed economies draw inward and face prolonged stagnation under demographic pressure, while emerging markets struggle to create sufficient employment for growing populations. The result is greater inequality, increased migration pressure, and economic fragmentation.

The most likely outcome lies between these extremes, but the direction will be shaped by policy, investment decisions, and institutional capacity.

Conclusion

Demographics are often treated as background conditions, but increasingly, they’re becoming primary drivers of economic change.

The aging of developed economies is already reshaping labor markets, fiscal systems, and long-term growth trajectories. At the same time, population expansion in emerging markets represents a significant shift in the geography of future economic activity.

This divergence will not resolve itself. It will be managed, well or poorly, through decisions on investment, infrastructure, and coordination.

The question isn’t whether this reshapes the global economy because it will. The question is whether the transition is managed in a way that distributes the benefits reasonably or whether it mostly produces new forms of inequality and instability, and that’s not really a question that economics alone can answer.