Across Africa, cities are expanding at a pace among the fastest in the world, as populations grow and people move from rural areas to urban centers in search of opportunity. The scale and speed of this urbanization represent one of the defining demographic shifts of the era, and the race to build the infrastructure, housing, and services to match it is shaping the economic and social future of a continent whose population is young and growing rapidly.

The drivers of this urban growth are powerful and largely structural. Africa’s population is expanding while much of the world’s is aging or stabilizing, and a large and youthful population is moving into the cities that offer the prospect of work, education, and a better life. The cities swell as a result, with some growing into vast metropolitan areas in a span of decades, a transformation that compresses into a short period the kind of urbanization that unfolded over much longer stretches elsewhere.

The opportunity that this urbanization presents is substantial. Cities concentrate people, ideas, and economic activity, and they can serve as engines of growth, productivity, and innovation. A young and growing urban population could provide the workforce and the dynamism to drive economic development, and the concentration of people in cities can make the provision of services and the building of markets more efficient. Realizing this potential, however, depends on whether the infrastructure and institutions can keep pace with the growth.

The challenge lies in that race between growth and the capacity to accommodate it. Building the housing, transportation, water, power, and sanitation systems that growing cities require demands enormous investment, and the pace of urban growth has in many places outstripped the pace at which this infrastructure can be built. The result is strain, visible in inadequate housing, congested transportation, unreliable services, and the spread of informal settlements that grow faster than the formal systems meant to serve them.

The financing of the needed infrastructure presents a formidable obstacle. The investment required to build the systems that rapidly growing cities need is vast, and mobilizing it strains the resources of governments contending with many competing demands and limited revenue. The search for financing has drawn in a range of sources, from domestic resources to international lenders and private investors, each with its own conditions and consequences, and the question of how to fund the infrastructure of urbanization without accumulating unsustainable debt remains pressing.

The way this urbanization is managed carries long-term consequences. Cities that grow with adequate planning and infrastructure can become engines of prosperity, while those whose growth outpaces their capacity can entrench problems that prove difficult to remedy later, as informal patterns of development harden and the cost of retrofitting infrastructure rises. The decisions made during this period of rapid growth, about how cities are planned, how infrastructure is financed, and how services are provided, will shape the trajectory of urban life on the continent for generations.

The urbanization of Africa is a transformation of global significance, given the scale of the population involved and the continent’s growing weight in the world. Whether the cities can build the infrastructure to match their growth, and whether the opportunity that urbanization presents can be realized, will influence not only the prosperity of the continent but the shape of the global economy and population in the decades ahead. The race between urban growth and the capacity to accommodate it is among the consequential contests of the era.