Rapidly Urbanizing Populations Face Unique Challenges

Author: Grant Potter
Grant Potter is an Executive Assistant at the Worldwatch Institute. 
  • The number of people residing in cities is expected to grow by 2.6 billion by 2050, 2.45 billion of which will live in developing countries. 
  • In Asia more than any other region, "megacities" (home to more than 10 million people) are likely to be the defining feature of this demographic shift. 
  • An increase in the number of people living in slums, where inhabitants lack basic security and sanitation, is expected to accompany the expansion of urban populations. 
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By 2050, nearly 95% of the growth in urban populations will occur in developing countries. (The Gates Foundation)

The world’s urban population is expected to grow by 2.6 billion people between 2011 and 2050, bringing the total number of urbanites to 6.3 billion. This urban expansion will be especially burdensome for developing countries, where 82 percent of the world’s population currently lives, I write in a new report for Vital Signs Online

Although the developing world is less urbanized than the industrial world in relative terms, developing countries are home to an estimated 1.54 billion more people. In absolute terms, the developing world is projected to add approximately 2.45 billion people to its cities by 2050, while the industrial world is due to add just 170 million.

Within the developing world, the vast majority of this urban growth is projected to occur in Asia and Africa. Asia far outstrips Africa in total population, with 4.2 billion people in 2011 compared with Africa’s 1 billion. But these regions are also the least urbanized areas on Earth: Asia’s population was 45 percent urban in 2011, and Africa’s was only 40 percent urban. In Latin America and the Caribbean, by contrast, 78 percent of the regions’ 599 million people live in cities.

A characteristic feature of Asian urbanization is the prevalence of “megacities” that are home to more than 10 million people. In 2011, there were 23 such cities worldwide, 13 of which were Asian. By 2025, the total number of megacities is expected to reach 37—with 21 in Asia alone. Specifically, Southeast Asia is home to the most densely populated cities: approximately 16,500 people per square kilometer are squeezed into the region’s urban areas.

Cities, especially in the developing world, must find a way to provide essential services to their ever-increasing populations. When cities fail to meet these essential needs on a large scale, they create areas known as slums, where households typically lack safe drinking water, safe sanitation, a durable living space, or security of a lease. According to UN HABITAT, 828 million people in developing-world cities are considered slum dwellers—one in every three residents. Slum populations are expected to grow significantly in the future, and UN HABITAT projects that 6 million more people live in slums every year.

The World Health Organization identifies the rapid increase of urban populations, especially slum populations, as the most important issue affecting health in the 21st century. The agency cites overcrowding, lack of safe water, and improper sanitation systems as the primary factors contributing to poor health among the urban poor. Slums often become breeding grounds for diseases like tuberculosis, dengue, pneumonia, and cholera, and slum dwellers contract water-borne or respiratory illnesses at much higher rates than people in rural areas do.

Cities and their slums will continue to grow as long as rural populations continue to migrate to cities to find economic and other opportunities, such as access to cultural amenities, education, and health care.

Click here to purchase the entire report.

Grant Potter | December 10, 2012