Urban population differentiation is reshaping the Global South: from migration, age structure, to the shift of growth centers

The Next Stage of Urbanization Is Not “More People Moving to Cities,” but “Which Cities Are Absorbing the Future”

Over the past two decades, the global growth narrative has long revolved around one core assumption: more people moving into cities means higher productivity, deeper marketization, and stronger industrial agglomeration effects. But the latest research on urban populations reminds us that this assumption is losing its simplicity. Urbanization is still continuing, but it no longer unfolds through uniform expansion; instead, it is reshaping the growth map of the Global South in markedly differentiated ways.

This Nature study covers age and gender structure data from more than 10,000 cities worldwide between 2000 and 2020. The results show that the global urban dependency ratio fell from 0.87 to 0.59, indicating that cities as a whole are still evolving toward structures more favorable to labor supply; but this trend is not evenly distributed. Smaller cities are generally younger than larger ones, and this is especially evident in Africa. At the same time, some cities in the Middle East and North Africa have seen a pronounced male population surplus, reflecting the close connection between cross-border labor migration and urban labor markets. The study also estimates that 45% of urban population growth came from net migration, while 55% came from natural increase.

Taken together, these facts point to a more important conclusion: the real differentiation in global urban growth lies not in “whether urbanization is happening,” but in “who is growing, in what structure, and whether that growth can be transformed into long-term productive capacity.”

For Emerging Markets, Demographics Have Already Become Part of the Investment Map

In the Global South, urban populations are not merely statistical concentrations; they are nodes where capital, labor, and public service capacity are all under pressure at once. In many low- and middle-income countries, urban growth is occurring before infrastructure, housing, transportation, water supply, and healthcare systems have finished expanding. In other words, population growth does not automatically bring dividends; if fiscal capacity and institutional supply fail to keep pace, the expansion of population size quickly turns into governance pressure.

This is precisely one of the most important structural differences between emerging markets and mature economies. Some cities in high-income countries are facing population decline and aging, which means social welfare, labor supply, and local finances are under reallocation pressure; meanwhile, cities in Africa, South Asia, and parts of Southeast Asia are facing the opposite problem: a continuous inflow of young people, with cities needing to expand housing, transportation, vocational education, and energy systems in a much shorter time.

From an investment perspective, this difference changes how capital judges markets. In the past, foreign investment often assessed markets on a country-by-country basis; now, more and more opportunities and risks are concentrated in specific cities and city clusters. A country’s macro-level demographic dividend does not mean its major cities also possess sustainable labor-absorption capacity. City-level age structure, gender structure, migration patterns, and the share of informal employment are becoming important variables in determining long-term returns.

The Youthfulness of Africa’s Small Cities Means Both Growth Opportunities and a Governance RaceThe study specifically points out that small cities are generally younger than large cities, and this phenomenon is most pronounced in Africa. This has long-term implications. For many African countries, the places that truly absorb new population and connect rural economies with national markets are not always capital cities or megacities, but a large number of secondary cities and small and medium-sized cities.

These cities often play three roles:

1. A transit point between agricultural hinterlands and consumer markets; 2. A base for regional logistics and basic manufacturing; 3. The first stop for rural populations entering the modern economic system.

Therefore, the youthfulness of secondary cities is not a marginal phenomenon, but a core component of the growth path of the Global South. It determines whether a country can turn population growth into productivity, rather than pushing population pressure onto the capital and a few coastal centers.

But youthfulness also means higher governance demands. When there are many young people, migration is rapid, and job opportunities are insufficient, cities can easily develop systemic shortages in housing, public transportation, basic education, and security management. If such gaps cannot be repaired for a long time, the demographic dividend will slide into social pressure, which in turn will affect the stability of local politics and a country’s investment rating.

Migration is not a supplementary variable, but one of the main engines of urban growth

Another key conclusion from the study is that about 45% of urban population growth comes from net migration. This proportion is enough to show that migration is no longer a peripheral factor in urban growth, but a core mechanism.

This is especially important for the Global South, because migration patterns determine the “quality” of urban population structure. Migration from rural areas usually means an increase in labor supply and consumer expansion, but it can also mean a mismatch of skills; cross-border migration further changes the gender structure, wage system, and housing demand of cities. The obvious male surplus in some cities in the Middle East and North Africa is precisely a signal of labor migration being embedded in the urban economy.

From a regional economic perspective, migration is also reallocating the distribution of resources. The concentration of labor in a few growth nodes will strengthen the productivity and tax base of core cities; but if this concentration happens too quickly and the regional infrastructure network is insufficient, it will widen development gaps between cities. The result is not that “the whole country urbanizes together,” but that a few cities are rapidly pushed into global competition, while others are left marginalized for a long time.

A more direct connection is forming between urban age structure and sovereign risk

Population structure is usually seen as a social issue, but in the Global South, it is increasingly close to a sovereign risk issue. The younger a city is, the stronger its dependence on employment, housing, education, and public services; once fiscal space is insufficient and policy implementation capacity is limited, instability in the city rises rapidly.

This is also why the link between demographic structure and political stability cannot be judged using only national averages. Age and gender differences within cities change resilience to risks. Cities with a higher share of young men, insufficient employment absorption, and a rising share of the informal sector are often more prone to social friction; aging cities, by contrast, face another set of constraints: shrinking tax bases, rising public spending, and labor shortages.In other words, a city’s demographic structure affects not only economic efficiency but also the cost of governance. For international capital, this means that risk distribution within the same country can be extremely uneven. Capital cities, port cities, industrial corridors, resource-based cities, and secondary cities are no longer separated by simple geographic differences, but by differences in institutional resilience.

Global capital is重新识别 “growth-capable cities”

If global capital over the past two decades has paid more attention to national GDP growth rates, then over the next decade a more important metric may be: which cities can convert population growth into productivity, and which cities can only absorb population without upgrading their economic structure.

This is also why infrastructure investment, urban renewal, housing finance, digital public services, and transportation networks are becoming key areas in emerging-market capital allocation. The younger a city is, the more upfront investment it requires; but if these investments do not pay off, urban expansion will turn into inefficient extensive growth. By contrast, if a city can form an industrial loop through the digital economy, light manufacturing, regional logistics, and service-sector upgrading, population gains may become the basis for long-term domestic demand.

Some emerging-market countries have already reflected this path differentiation to varying degrees. Certain medium-sized cities in Southeast Asia are benefiting from supply chain shifts and manufacturing decentralization; some cities in Africa rely more on population growth and regional trade; while some cities in the Middle East are seeking a balance between labor migration and service-sector expansion. Together, they show that urbanization is not a single model, but the result of industrial structure, migration institutions, and fiscal capacity.

Urban divergence is, in fact, a micro projection of the shift in global growth centers

Viewed over a longer cycle, what this study reveals is not just changes in urban populations, but structural evidence that the center of gravity of the global economy is continuing to move toward the Global South. The concentration of the world’s population in cities is mainly taking place in low-income and middle-income countries; but these countries are not benefiting equally. Only a small number of cities and urban agglomerations truly have the capacity to absorb industry, capital, and population.

This means that the future shift in global growth centers will not necessarily be manifested as the rise of a single country, but more likely as the reorganization of a network of cities:

• Secondary cities in Africa will shoulder regional market and labor-absorbing functions;
• South Asian cities will continue to bear high population density and infrastructure pressure;
• Southeast Asian cities will enhance their ability to connect to global supply chains amid manufacturing relocation;
• Middle Eastern cities will seek a new balance among labor migration, the reallocation of energy revenues, and service-sector transformation.

Cities are both carriers of growth and amplifiers of risk. A younger population can become a demographic dividend, or it can become a governance deficit; migration can optimize labor allocation, or it can be a source of imbalanced social services. What determines the difference is not population itself, but whether a city has the mechanisms to turn demographic change into institutional capacity and industrial capacity.

Conclusion: Urban competition in the Global South has already entered a stage of “structural screening”

This study is most noteworthy in that it reminds us: urbanization does not automatically bring balanced development.The most noteworthy aspect of this study is that it reminds us: urbanization does not automatically bring balanced development. On the contrary, the global urban system is undergoing a round of structural screening— which cities can absorb young populations, attract migration, expand infrastructure, and form industrial clusters, and which cities will accumulate vulnerability amid growth.

For the Global South, what this screening determines is not only the future of cities, but also the quality of national future growth. Whether the demographic dividend can be realized, whether foreign capital is willing to stay for the long term, whether supply chains will continue to shift, and whether regional cooperation can improve logistics and employment—ultimately all of these depend on the urban level.

Therefore, to understand the next stage of emerging markets, we cannot look only at average national growth rates; we must also look at urban population structure, migration flows, and infrastructure response capacity. The real shift in global growth centers often does not appear first in macro data, but rather in city neighborhoods, commuting networks, housing markets, and labor mobility.