The City Solution

Why cities are the best cure for our planet’s growing pains

This story appears in the December 2011 issue of National Geographic magazine.

At the time of Jack the Ripper, a hard time for London, there lived in that city a mild-mannered stenographer named Ebenezer Howard. He's worth mentioning because he had a large and lingering impact on how we think about cities.

Howard was bald, with a bushy, mouth-cloaking mustache, wire-rim spectacles, and the distracted air of a seeker. His job transcribing speeches did not fulfill him. He dabbled in spiritualism; mastered Esperanto, the recently invented language; invented a shorthand typewriter himself. And dreamed about real estate. What his family needed, he wrote to his wife in 1885, was a house with "a really nice garden with perhaps a lawn tennis ground." A few years later, after siring four children in six years in a cramped rental house, Howard emerged from a prolonged depression with a scheme for emptying out London.

London in the 1880s, you see, was booming, but it was also bursting with people far more desperate than Howard. The slums where the Ripper trolled for victims were beyond appalling. "Every room in these rotten and reeking tenements houses a family, often two," wrote Andrew Mearns, a crusading minister. "In one cellar a sanitary inspector reports finding a father, mother, three children, and four pigs! … Elsewhere is a poor widow, her three children, and a child who had been dead thirteen days." The Victorians called such slums rookeries, or colonies of breeding animals. The chairman of the London County Council described his city as "a tumour, an elephantiasis sucking into its gorged system half the life and the blood and the bone of the rural districts."

Urban planning in the 20th century sprang from that horrified perception of 19th-century cities. Oddly, it began with Ebenezer Howard. In a slim book, self-published in 1898, the man who spent his days transcribing the ideas of others articulated his own vision for how humanity ought to live—a vision so compelling that half a century later Lewis Mumford, the great American architecture critic, said it had "laid the foundation for a new cycle in urban civilization."

The tide of urbanization must be stopped, Howard argued, by drawing people away from the cancerous metropolises into new, self-contained "garden cities." The residents of these happy little islands would feel the "joyous union" of town and country. They'd live in nice houses and gardens at the center, walk to work in factories at the rim, and be fed by farms in an outer greenbelt—which would also stop the town from expanding into the country. When one town filled to its greenbelt—32,000 people was the right number, Howard thought—it would be time to build the next one. In 1907, welcoming 500 Esperantists to Letchworth, the first garden city, Howard boldly predicted (in Esperanto) that both the new language and his new utopias would soon spread around the world.

He was right about the human desire for more living space but wrong about the future of cities: It's the tide of urbanization that has spread around the world. In the developed countries and Latin America it has nearly crested; more than 70 percent of people there live in urban areas. In much of Asia and Africa people are still surging into cities, in numbers swollen by the population boom. Most urbanites live in cities of less than half a million, but big cities have gotten bigger and more common. In the 19th century London was the only city of more than five million; now there are 54, most of them in Asia.

And here's one more change since then: Urbanization is now good news. Expert opinion has shifted profoundly in the past decade or two. Though slums as appalling as Victorian London's are now widespread, and the Victorian fear of cities lives on, cancer no longer seems the right metaphor. On the contrary: With Earth's population headed toward nine or ten billion, dense cities are looking more like a cure—the best hope for lifting people out of poverty without wrecking the planet.

One evening last March, Harvard economist Edward Glaeser appeared at the London School of Economics to promote this point of view, along with his new book,Triumph of the City. Glaeser, who grew up in New York City and talks extremely fast, came heavily armed with anecdotes and data. "There's no such thing as a poor urbanized country; there's no such thing as a rich rural country," he said. A cloud of country names, each plotted by GDP and urbanization rate, flashed on the screen behind him.

Mahatma Gandhi was wrong, Glaeser declared—India's future is not in its villages, it's in Bangalore. Images of Dharavi, Mumbai's large slum, and of Rio de Janeiro's favelas flashed by; to Glaeser, they were examples of urban vitality, not blight. Poor people flock to cities because that's where the money is, he said, and cities produce more because "the absence of space between people" reduces the cost of transporting goods, people, and ideas. Historically, cities were built on rivers or natural harbors to ease the flow of goods. But these days, since shipping costs have declined and service industries have risen, what counts most is the flow of ideas.

The quintessence of the vibrant city for Glaeser is Wall Street, especially the trading floor, where millionaires forsake large offices to work in an open-plan bath of information. "They value knowledge over space—that's what the modern city is all about," he said. Successful cities "increase the returns to being smart" by enabling people to learn from one another. In cities with higher average education, even the uneducated earn higher wages; that's evidence of "human capital spillover."

Spillover works best face-to-face. No technology yet invented—not the telephone, the Internet, or videoconferencing—delivers the fertile chance encounters that cities have delivered since the Roman Forum was new. Nor do they deliver the nonverbal, contextual cues that help us convey complex ideas—to see from the glassy eyes of our listeners, for instance, that we're talking too fast.

It's easy to see why economists would embrace cities, warts and all, as engines of prosperity. It has taken a bit longer for environmentalists, for whom Henry David Thoreau's cabin in the woods has been a lodestar. By increasing income, cities increase consumption and pollution too. If what you value most is nature, cities look like concentrated piles of damage—until you consider the alternative, which is spreading the damage. From an ecological standpoint, says Stewart Brand, founder of the Whole Earth Catalog and now a champion of urbanization, a back-to-the-land ethic would be disastrous. (Thoreau, Glaeser points out gleefully, once accidentally burned down 300 acres of forest.) Cities allow half of humanity to live on around 4 percent of the arable land, leaving more space for open country.

Per capita, city dwellers tread more lightly in other ways as well, as David Owen explains in Green Metropolis. Their roads, sewers, and power lines are shorter and so use fewer resources. Their apartments take less energy to heat, cool, and light than do houses. Most important, people in dense cities drive less. Their destinations are close enough to walk to, and enough people are going to the same places to make public transit practical. In cities like New York, per capita energy use and carbon emissions are much lower than the national average.

Cities in developing countries are even denser and use far fewer resources. But that's mostly because poor people don't consume a lot. Dharavi may be a "model of low emissions," says David Satterthwaite of London's International Institute for Environment and Development, but its residents lack safe water, toilets, and garbage collection. So do perhaps a billion other city dwellers in developing countries. And it is such cities, the United Nations projects, that will absorb most of the world's population increase between now and 2050—more than two billion people. How their governments respond will affect us all.

Many are responding the way Britain did to the growth of London in the 19th century: by trying to make it stop. A UN survey reports that 72 percent of developing countries have adopted policies designed to stem the tide of migration to their cities. But it's a mistake to see urbanization itself as evil rather than as an inevitable part of development, says Satterthwaite, who advises governments and associations of slum dwellers around the world. "I don't get scared by rapid growth," he says. "I meet African mayors who tell me, 'There are too many people moving here!' I tell them, 'No, the problem is your inability to govern them.'"

There is no single model for how to manage rapid urbanization, but there are hopeful examples. One is Seoul, the capital of South Korea.

Between 1960 and 2000 Seoul's population zoomed from fewer than three million to ten million, and South Korea went from being one of the world's poorest countries, with a per capita GDP of less than $100, to being richer than some in Europe. The speed of the transformation shows. Driving into Seoul on the highway along the Han River, you pass a distressingly homogeneous sea of concrete apartment blocks, each emblazoned with a large number to distinguish it from its clones. Not so long ago though, many Koreans lived in shanties. The apartment blocks may be uninspiring on the outside, urban planner Yeong-Hee Jang told me, but life inside "is so warm and convenient." She repeated the word "warm" three times.

Every city is a unique mix of the planned and the unplanned, of features that were intentionally designed by government and others that emerged organically, over time, from choices made by the residents. Seoul was planned from the start. The monks who chose the site in 1394 for King Taejo, founder of the Choson dynasty, followed the ancient principles of feng shui. They placed the king's palace at an auspicious spot, with the Han River in front and a large mountain in back to shield it from the north wind. For five centuries the city stayed mostly inside a ten-mile-long wall that Taejo's men had built in six months. It was a cloistered, scholarly town of a few hundred thousand. Then the 20th century cleaned its slate.

World War II and then the Korean War, which ended in 1953, brought more than a million refugees to the bombed-out city. Not much of Seoul was left—but it was filled for the first time with a potent mix of people. They were burning to improve their miserable lot. In their hearts, the ancient Confucian virtues of loyalty and respect for hierarchy fused uneasily with Western longings for democracy and material goods. "The explosive energy of my generation," says Hong-Bin Kang, a former vice mayor who now runs Seoul's history museum, dates from this period. So does South Korea's population explosion, which was triggered, as elsewhere, by rapid improvements in public health and nutrition.

It's an uncomfortable fact that a dictator helped organize all that energy. When Park Chung-Hee took power in a military coup in 1961, his government funneled foreign capital into Korean companies that made things foreigners would buy—knockoff clothes and wigs at first, later steel, electronics, and cars. Central to the process, which created conglomerates like Samsung and Hyundai, were the women and men streaming into Seoul to work in its new factories and educate themselves at its universities. "You can't understand urbanization in isolation from economic development," says economist Kyung-Hwan Kim of Sogang University. The growing city enabled the economic boom, which paid for the infrastructure that helped the city absorb the country's growing population.

A lot was lost in the bulldozing, high-rising rush. If you lived in old Seoul, north of the Han River, in the 1970s and 1980s, you watched an entirely new Seoul rise from verdant paddies on the south bank, in the area called Kangnam. You watched the city's growing middle and upper classes leave sinuous alleys and traditional houses—lovely wooden hanok, with courtyards and gracefully curved tile roofs—for antiseptic high-rises and a grid of car-friendly boulevards. "Seoul lost its color," says Choo Chin Woo, an investigative journalist at the newsweekly SisaIN. "Apartment high-rises all over town—it looks stupid." Worse, the poor often got shunted aside as their makeshift neighborhoods were redeveloped with high-rises they couldn't afford.

But over the years an increasing share of the population has been able to cash in on the housing boom. Today half the people in Seoul own apartments. Koreans like to heat their homes to 77 degrees, says urban planner Yeong-Hee Jang, and in their well-equipped apartments they can afford to do that. One reason the buildings in Kangnam line up like soldiers on parade, she adds, is that everyone wants an apartment that faces south—for warmth as well as feng shui.

Seoul today is one of the densest cities in the world. It has millions of cars but also an excellent subway system. Even in the newer districts the streets seem, to a Westerner, anything but colorless. They're vibrant with commerce and crowded with pedestrians, each of whom has a carbon footprint less than half the size of a New Yorker's. Life has gotten much better for Koreans as the country has gone from 28 percent urban in 1961 to 83 percent today. Life expectancy has increased from 51 years to 79—a year longer than for Americans. Korean boys now grow six inches taller than they used to.

South Korea's experience can't be easily copied, but it does prove that a poor country can urbanize successfully and incredibly fast. In the late 1990s Kyung-Hwan Kim worked for the UN in Nairobi, advising African cities on their staggering financial problems. "Every time I visited one of these cities I asked myself, What would a visiting consultant have said to Koreans in 1960?" he says. "Would he have imagined Korea as it was 40 years later? The chances are close to zero."

The fear of urbanization has not been good for cities, or for their countries, or for the planet. South Korea, ironically, has never quite shaken the notion that its great capital is a tumor sucking life from the rest of the country. Right now the government is building a second capital 75 miles to the south; starting in 2012, it plans to move half its ministries there and to scatter other public institutions around the country, in the hope of spreading Seoul's wealth. The nation's efforts to stop Seoul's growth go back to Park Chung-Hee, the dictator who jump-started the economy. In 1971, as the city's population was skyrocketing past five million, Park took a page from the book of Ebenezer Howard. He surrounded the city with a wide greenbelt to halt further development, just as London had in 1947.

Both greenbelts preserved open space, but neither stopped the growth of the city; people now commute from suburbs that leapfrogged the restraints. "Greenbelts have had the effect of pushing people farther out, sometimes absurdly far," says Peter Hall, a planner and historian at University College London. Brasília, the planned capital of Brazil, was designed for 500,000 people; two million more now live beyond the lake and park that were supposed to block the city's expansion. When you try to stop urban growth, it seems, you just amplify sprawl.

Sprawl preoccupies urban planners today, as its antithesis, density, did a century ago. London is no longer decried as a tumor, but Atlanta has been called "a pulsating slime mold" (by James Howard Kunstler, a colorful critic of suburbia) on account of its extreme sprawl. Greenbelts aren't the cause of sprawl; most cities don't have them. Other government policies, such as subsidies for highways and home ownership, have coaxed the suburbs outward. So has that other great shaper of the destiny of cities—the choices made by individual residents. Ebenezer Howard was right about that much: A lot of people want nice houses with gardens.

Sprawl is not just a Western phenomenon. By consulting satellite images, old maps, and census data, Shlomo Angel, an urban planning professor at New York University and Princeton, has tracked how 120 cities changed in shape and population density between 1990 and 2000. Even in developing countries most cities are spreading out faster than people pour into them; on average they're getting 2 percent less dense each year. By 2030 their built-up area could triple. What's driving the expansion? Rising incomes and cheap transportation. "When income rises, people have money to buy more space," Angel explains. With cheap transportation, they can afford to travel longer distances from home to work.

But it matters what kind of homes they live in and what transportation they use. In the 20th century American cities were redesigned around cars—wonderful, liberating machines that also make city air unbreathable and carry suburbs beyond the horizon. Car-centered sprawl gobbles farmland, energy, and other resources. These days, planners in the U.S. want to repopulate downtowns and densify suburbs, by building walkable town centers, for instance, in the parking lots of failed malls. Urban flight, which seemed a good idea a century ago, now seems in the West like a historic wrong turn. Meanwhile in China and India, where people are still flooding into cities, car sales are booming. "It would be a lot better for the planet," Edward Glaeser writes, if people in those countries end up "in dense cities built around the elevator, rather than in sprawling areas built around the car."

Developing cities will inevitably expand, says Angel. Somewhere between the anarchy that prevails in many today and the utopianism that has often characterized urban planning lies a modest kind of planning that could make a big difference. It requires looking decades ahead, Angel says, and reserving land, before the city grows over it, for parks and a dense grid of public-transit corridors. It starts with looking at growing cities in a positive way—not as diseases, but as concentrations of human energy to be organized and tapped.

With its quiet commercial streets and Arts and Crafts houses, Letchworth, England, today feels a bit like the garden city that time forgot. Ebenezer Howard's ideal of a self-sustaining community never happened. The farmers in Letchworth's greenbelt sell their sugar beets and wheat to a large cereal company. The town's residents work mostly in London or Cambridge. John Lewis, who runs the foundation that Howard started, which still owns much of the town's land, worries that Letchworth is "in danger of becoming a dormitory." Still, it has a key aspect of what many planners today think of as sustainability: It wasn't designed around cars. Howard ignored the new invention. From anywhere in Letchworth you can walk to the center of town to shop or take the train to London. The truth is, Letchworth looks like a very nice place to live; it's just not for everyone. No place is.

Thirty-five miles to the south, London remains unsupplanted. Eight million people live there now. All attempts to impose sense on its maze of streets have failed, as anyone who has crossed the city in a taxi can attest. "London wasn't planned at all!" Peter Hall exclaimed one afternoon as we stepped into the street in front of the British Academy. But the city did two sensible things as it ballooned outward in the 19th and 20th centuries, Hall said. It preserved large, semiwild parks like Hampstead Heath, where citizens can commune with nature. Most important, it expanded along railway and subway lines. "Get the transportation right," said Hall. "Then let things happen."

With that he disappeared into the Underground for his ride home, leaving me on the crowded sidewalk with a great gift: a few hours to kill in London. Even Ebenezer Howard would have understood the feeling, at least as a young man. When he returned after a few years in the U.S.—he'd flopped as a homesteading farmer in Nebraska—he was jazzed by his native city. Just riding an omnibus, he later wrote, gave him a pleasantly visceral jolt: "A strange ecstatic feeling at such times often possessed me … The crowded streets—the signs of wealth and prosperity—the bustle—the very confusion and disorder appealed to me, and I was filled with delight."