Bright Lights, Big Cities

Slums are burgeoning worldwide— and that’s a good thing.

Sometime next year, most likely with the birth of a child in a small, booming city in Africa or Asia, people living in cities will outnumber those outside for the first time. There’s a good chance, 1 in 3, that the child will be born in a slum.

Cities in the developing world are feeling the strain of all their new residents: According to the United Nations Population Fund, the cities of Africa and Asia will double in population between 2000 and 2030, and the poor will continue to flow into shantytowns. Worldwide, the number of slum dwellers has grown from 715 million in 1990 to roughly a billion today, and it’s expected to hit 1.4 billion by 2020. When we think of typical poverty or a typical city, we should no longer imagine thirsty villagers or Chicago’s skyscrapers, but a squatters’ settlement.

Despite the often-squalid conditions, migrants keep streaming in for a reason. While urban poverty is more concentrated, more visible, and hence seemingly more desperate than the rural variety, migration into cities appears to reduce poverty in poor countries. In Brazil, for example, 66 percent of migrants to cities earn more money; the gains are highest for unskilled workers. According to the UN’s “State of World Population 2007” report, since the 1990s, perhaps 10 percent of the poverty reduction achieved by developing countries has been the result of migration from the countryside. And since the beginning of the industrial age, the authors note, no country has grown rich before its people first shifted to cities.

Media coverage of cities in the developing world has focused mostly on the megacities—areas with 10 million or more residents. Some of these—like Lagos, Nigeria, and Dhaka, Bangladesh—continue to grow at a breakneck pace. But many of the world’s urban giants—Buenos Aires, Kolkata, Mexico City—are now shrinking, as their disadvantages (the sprawl and crush that stifle the movement of people, goods, and waste) come to outweigh their benefits.

Most of the action today is in smaller cities. More than half of the world’s urban dwellers live in cities of fewer than 500,000, and cities of 1 million to 5 million are growing the fastest. Advances in transportation and communication have made it easier to do business in these second-tier cities, and made it easier for such cities to flourish along with the global economy.

Poor countries often try to stop slum growth, evicting migrants and denying water and sanitation to new slum developments. There’s a certain political logic to these strategies—concentrated populations can be more demanding and disruptive—and no city wants sprawling slums. But countries trying to slow urban growth are harming their citizens and economies. What’s more, their efforts usually fail, worsening slum conditions without stopping slum growth.

The UN report suggests that governments would do better if they accepted the inevitability of new city dwellers and tried to work with them: Plan ahead, provide the basics—access to water, electricity, and roads—then get out of the way. Entrepreneurial hustle fills the slums; let the same drive that brings millions to the city improve it from the bottom up.

Countries serious about slowing the growth of their cities without trapping their citizens in poverty might try a method more effective than demolishing shantytowns. Over half of city growth now comes from natural increase—births less deaths—not from migration. (China, with its aging population and one-child-policy legacy, is a notable exception.) The best antidote to the ills of urban crowding, over the long term, might be a new emphasis on education, contraception, and women’s rights.

[Click here to view a larger version of the map above.]

The image above shows the intensifying nighttime glow, a sign of rapid urbanization, from 1992 to 2003 in the Nile Delta and on the Mediterranean coast of the Middle East. Spots that have been bright throughout the period are black; those that have been dim are cyan. Blue areas indicate diminishing light, and yellow areas new light. The map’s most prominent colors, orange and red, show a substantial intensification of light.

Few places on Earth are more densely populated than the Palestinian territories. And the Nile is overflowing with people: In the past 30 years, Cairo has nearly doubled its population, to 12 million, its slums extending ever outward; tens of thousands of residents, at least, inhabit old crypts. The state has tried, with some success, to divert squatters to new cities built in the desert. Still, more than 90 percent of Egyptians live on the narrow arable strip along the Nile. It is rapidly being built over.