The demographic challenge in cities

Cities have powered the world economy for centuries. Large cities generate about 75 percent of global GDP today and will generate 86 percent of worldwide GDP growth between 2015 and 2030. Population growth has been the crucial driver of cities’ GDP growth, accounting for 58 percent of it among large cities between 2000 and 2012. Rising per capita income contributed the other 42 percent.

However, the world’s cities are facing more challenging demographics, and the days of easy growth are over. In the past, city economies expanded largely because their populations were increasing due to high birthrates and mass migration from rural areas. Both of those sources of population growth are now diminishing. Global population growth is slowing because of declining fertility rates and aging. At the same time, rural-to-urban migration is running its course and plateauing in many regions. How cities adjust to the new reality is important not only for their prospects but also for those of nations that will continue to rely on thriving cities for rising prosperity.

The double hit of slowing population growth and plateauing urbanization caused population to decline in 6 percent of the world’s largest cities—with the largest share in developed economies—between 2000 and 2015. From 2015 to 2025, we expect population to decline in 17 percent of large cities in developed regions and in 8 percent of all large cities. In the developed world, the urban population in Canada and the United States grew at a compound annual rate of 2.2 percent between 1950 and 1970 but dropped to only 1.0 percent from 2010 to 2015. That rate is expected to persist until 2025 and then to decline even further, to 0.8 percent from 2025 to 2035. Although the demographic shift is more advanced in developed regions, it also affects emerging regions.

This is a challenge to the economic prospects of cities that marks a distinct break from recent history. The past 50 years were truly unusual in demographic terms, as large cohorts of working-age populations fueled the growth of cities and nations. In the new demographic era, we are likely to see a much more fragmented urban landscape, with pockets of robust expansion but also areas of stagnant and declining populations. Cities’ growth prospects will reflect very different demographic footprints and dynamics shaped by their local birth and death rates, net domestic migration, and net international migration.