Triumph of the City

by Edward Glaeser

  Smokey the Bear could use this story to teach children the dangers of forest fires, but at least one of the culprits steadfastly denied any guilt. He wrote: “I have set fire to the forest, but I have done no wrong therein, and now it is as if the lightning had done it.” The other residents of Concord were less forgiving, taking an understandably dim view of even inadvertent arson. They called the young incendiary a “dammed rascal” and a “flibbertigibbet.” The Concord Freeman’s text sounds like a stuffy nineteenth-century New Englander channeling Smokey: “It is to be hoped that this unfortunate result of sheer carelessness, will be borne in mind by those who may visit the woods for recreation.”

  The unrepentant forest burner was Henry David Thoreau, a somewhat underemployed Harvard graduate who has since become the secular saint of environmentalism. Thoreau’s Walden is one of those rare books whose influence seems only to grow over time. During his lifetime, his journal, describing two years of isolated living, received little attention. But in the twentieth century, it became a global bestseller, read by millions and taught by environmentally conscious high school teachers around the world.

  Thoreau loved the woods, but he was also part of an urban chain of intellectuals. He had been educated in the intellectual hothouse of early nineteenth-century Harvard. More important, he was one of a remarkable concentration of minds brought together by Ralph Waldo Emerson in Concord, a town filled with creative thinkers. Emerson assembled, and occasionally funded, brilliant minds, including Herman Melville, Nathanial Hawthorne, Margaret Fuller, Bronson Alcott, Louisa May Alcott, and Thoreau.

  Thoreau was part of Emerson’s Transcendentalist salon, but he extolled the virtues of rural isolation rather than urban interaction. In his introduction to Walden, Emerson described Thoreau thus: “An iconoclast in literature, he seldom thanked colleagues for their services to him, holding them in small esteem, whilst yet his debt to them was important.” Would Thoreau have been able to write so well about living alone if he hadn’t also connected with so many smart people in towns? Yet the eloquent cadences of Walden preach the virtues of sylvan solitude. Just as Thoreau and his disciples have rarely seen the virtues of cities, they have also had little empathy for the Concord Freeman’s warnings against rural recreation.

  Thoreau’s walk in the woods did much more for his soul than for the woods themselves, and my move into the countryside has done nothing but harm the environment. I’ve gone from being a relatively parsimonious urban energy user to emitting massive amounts of carbon. While my compact urban living space could be easily warmed, it takes hundreds of gallons of fuel oil to heat my drafty home over a New England winter. My modest attempts to reduce energy use have led my mother to accuse me of trying to freeze my children. I call it building character. What with lights and air conditioning and appliances, my electricity bill has tripled. Of course, like most of nonurban America, I’ve also become dependent on the car, burning roughly a gallon of gas every time I go to a full-size grocery store. It all seems pretty absurd to someone who, city-born, didn’t learn how to drive until he was in graduate school.

  My story, like Thoreau’s, makes a fundamental point: Cities are much better for the environment than leafy living. Residing in a forest might seem to be a good way of showing one’s love of nature, but living in a concrete jungle is actually far more ecologically friendly. We humans are a destructive species, even when, like Thoreau, we’re not trying to be. We burn forests and oil and inevitably hurt the landscape that surrounds us. If you love nature, stay away from it.

  In the 1970s, Jane Jacobs argued that we could minimize our damage to the environment by clustering together in high-rises and walking to work, and this point has been eloquently argued by David Owen in his book Green Metropolis. We maximize our damage when we insist on living surrounded by greensward. Lower densities inevitably mean more travel, and that requires energy. While larger living spaces certainly do have their advantages, large suburban homes also consume much more energy.

  There is still much debate about the relationship between greenhouse gases and global warming, and there is plenty of uncertainty about the effects global warming will have on the planet. I am no climatologist, and I have little to add to these contentious discussions. However, even those who doubt that humans are responsible for much of the recent rise in global temperature should still recognize that there are environmental risks associated with massively increasing the amount of carbon we emit.

  Anyone who believes that global warming is a real danger should see dense urban living as part of the solution. Over the next fifty years, China and India will cease to be poor rural nations, and that’s a good thing. They—like the United States and Europe before them—will move from farms to urban living. If billions of Chinese and Indians insist on leafy suburbs and the large homes and cars those suburbs entail, then the world’s carbon emissions will soar. Some environmentalists seem to wish that these countries would just stay rural. Thank goodness that isn’t a real option. Remaining rural means poverty and its attendant curses. The critical question is whether, as Asia develops, it will become a continent of suburban drivers or urban public-transit users.

  Environmentalists can make the case for greener living in dense cities, but to do this they must give up their antipathy to concrete. Today ecofriendly households raise their children on Dr. Seuss’s fable The Lorax, which depicts a callous city destroying a once beautiful landscape. True environmentalists should toss their copies of this book into the recycling bin and denounce the Lorax fallacy—that cities are bad for the environment. High-rise pioneers like William Le Baron Jenney and A. E. Lefcourt are better guides to a greener future than Henry David Thoreau.

  The Dream of Garden Living

  It is, of course, unfair to single Thoreau out for touting low-density living. For millennia, writers have praised the virtues of going back to nature, which actually made some sense before cities got clean water. The classical poet Horace, who left his father’s farm to be educated in Athens and Rome, wrote, “The chorus of writers, one and entire, detests the town and yearns for the sacred grove.” At the start of the nineteenth century, the age-old pleasures of English country living acquired one of the greatest public relations teams ever. Wordsworth, Coleridge, Keats, Shelley, and their fellow Romantic poets all extolled the magnificence of the countryside.

  These poets were reacting to the first explosion of industrial urbanization. They understandably saw more poetry in autumn or the west wind than in a textile mill. Byron was one of the Luddites’ few defenders in the House of Lords. In a sense, Thoreau’s years in Walden were just a more extreme version of Wordsworth’s life in the Lake District. Indeed, neither one was crazy to flee the disease and disorder of nineteenth-century cities, where life was too often nasty, brutish, and short.

  The Romantics’ love of nature spread to the more practical arts of architecture and urban planning. John Ruskin was raised in early nineteenth-century London, but as an art critic, he urged painters to “go to nature in all singleness of heart ... rejecting nothing and selecting nothing.” He loathed the standardization that marked both industrialization and classical art forms. He favored the vagaries of nature and Gothic structures. Ruskin was also an early advocate of town planning. He urged that “from any part of the city perfectly fresh air and grass and the sight of far horizon might be reachable in a few minutes walk.” He had in mind a compact, walled town, girded by a “belt of beautiful garden and orchard round the walls.” Ruskin’s message underwent a slight metamorphosis when it crossed the Atlantic, for Peter B. Wight, who helped make urban skyscrapers possible in the United States, started off as one of Ruskin’s most fervent American apostles.

  Enjoying nature is something of a luxury good, which may explain why environmentalism has grown stronger as mankind has gotten richer. Hungry people can be skittish about giving up a decent meal for a “sight of far horizon.” The poor farmers who came to Manchester’s mills were willingly abandoning nature in ord
er to put bread on their tables. But as the world grew wealthier over the nineteenth century, an increasingly large segment of the population came to want a little green mixed in with the urban density. Open spaces offered a bit of relief from the foul air and water of the early industrial cities.

  Historically, the wealthy managed to combine city and country by having two homes. Winter months were spent in the city. In the hot summers, when disease spread most virulently, the prosperous fled cities for their country estates. Yet this two-home model has remained relatively rare, because building two houses is such an expensive way for city dwellers to get access to the countryside. Out of America’s total housing stock of 128 million units, only a little more than 3 million are recreational second homes.

  A more affordable alternative is bringing the countryside into the city, which city planners have long strived to do. Ruskin offered one variant of this ideal: the small town surrounded by a greenbelt. Ebenezer Howard, a towering figure in urban planning, wrote his classic Garden Cities of Tomorrow in 1898 and made Ruskin’s vision concrete both intellectually and literally. Howard’s garden cities were to be surrounded by abundant land, which would provide food, clean air, and recreational space for the urbanites. During the twentieth century, greenbelts became a regular feature of English town planning. Today London’s Green Belt covers more than two thousand square miles, Toronto’s is even larger, and these rings of nature have also become popular in America’s Pacific Northwest.

  London’s Green Belt does, however, show the limitations of this strategy. If you’re in central London, the Green Belt is hardly within walking distance; it can easily take an hour on mass transit to get outside of London’s city limits. Greenbelts may serve to check urban growth—which may or may not be desirable—but they certainly don’t bring trees into the daily life of big-city residents.

  To make up for this shortfall, nineteenth-century urban planners built parks. In the United States, Frederick Law Olmsted specialized in bringing bucolic vistas to the heart of a city. Olmsted’s Central Park in New York remains a remarkable example of a man-made sylvan wonderland in the heart of an extremely dense place. Olmsted also gave Boston an emerald necklace, built Jackson Park in Chicago, and provided Detroit with Belle Isle. He built green spaces in Buffalo, Louisville, Milwaukee, Montreal, and Washington, D.C., and helped plan the campuses of both Berkeley and Stanford. While some might debate the merits of each individual project, most city dwellers blessed with an Olmsted creation have been grateful that he leavened their dense cities with a touch of leaf.

  But neither greenbelts nor central parks became the dominant way of merging city and country. Instead, millions of people adopted a far more extreme approach—following Thoreau and Wordsworth far more completely. Starting in the late nineteenth century, suburban developments made quasi-country estates more affordable to ordinary people. From Bryn Mawr to Houston’s Woodlands, developers have built homes on generous wooded plots. Why put up with the inconvenience of shared parks or long trips to the countryside when you could live, like Thoreau, with your own trees right outside your door?

  The emergence of faster, cheaper transportation made it possible to live with trees and work in the city. Streetcars enabled towns like Brookline, Massachusetts, to grow as they offered green spaces and access to urban density simultaneously. As an 1841 description notes, “The whole of this neighborhood of Brookline is a kind of landscape garden, and there is nothing in America of the sort, so inexpressibly charming as the lanes which lead from one cottage, or villa, to another.” Who wouldn’t want that, at least if you can afford it?

  Olmsted himself got into the suburb-building business in 1869 by designing Riverside, on the edge of Chicago, which may be America’s first “planned” suburban community. Together with his partner, Calvert Vaux, he eschewed the regularity of a grid in favor of curving roads laid out along natural pathways. Lots were large and trees were abundant. The modern suburb was born.

  Still, as late as the 1920s, many urban analysts missed the trend toward tree-lined suburban living. Architects like Raymond Hood (who later built Rockefeller Center), Hugh Ferriss, and others saw an urban future that looked like Batman’s Gotham City. Indeed, Ferriss’s drawings would be an inspiration for the comic book. They envisioned a vertical world of taller and taller buildings connected by multilevel highways with embedded airplane hangars. Le Corbusier’s city of the future included a lot more greenery, but it was still a world of vast towers, and Fritz Lang’s 1927 film Metropolis provides the ultimate dark vision of this urban future.

  As it turned out, the 1920s were the high-water mark for vertical America. Between 1930 and 1933, five new buildings opened that soared above 849 feet, the height of the tallest skyscraper in Western Europe today. America would not build another tower that tall for another thirty-six years. The move upward was overshadowed by the growth of places that looked more like Brookline and Riverside than like Rockefeller Center. Streetcars had made leafy living close to the city available for a moderate number of prosperous urban burghers, and cars made suburbs available to anyone in the middle class. As the car finally bested the elevator, the majority of Americans came to live in suburban places that combined city and nature.

  While the car enabled people to suburbanize, environmentalists meanwhile protected millions of acres of land within urban areas so that people could experience the countryside constantly. In the beautiful landscape of the San Francisco region there are endless miles of open mountain ranges and protected seascape. The computer magnates of Silicon Valley live in a region blessed not only by an extraordinary climate, but also by a beautiful setting protected from development by some of the world’s most restrictive land-use controls.

  America seemed on a path to widespread Walden living, where everyone could be surrounded by greenery, but somewhere along that road, something went environmentally wrong. The dream of garden living envisioned by Ruskin and Wordsworth and designed by Howard and Olmsted turned out to be an ecological nightmare. Just as Thoreau’s forest fire suggests, living within nature can have terrible consequences for the environment. The move to low-density living ended up being far less sensitive to nature than Ferriss’s vision of a towering metropolis.

  We’ve all heard the dire warnings from an Oscar-winning former vice president and climatologists alike about how carbon dioxide emissions are causing the earth to warm. Global temperatures have been rising continuously for close to sixty years. At the same time, carbon dioxide in the atmosphere continues to grow. Higher levels of carbon dioxide are thought to create higher temperatures through the greenhouse effect, whereby gases in the atmosphere absorb infrared radiation and warm the land below. The basic intuition of the mainstream hypothesis on climate change is that more greenhouse gases mean more infrared absorption and higher surface temperatures.

  For those of us who endure New England or Midwestern winters, a few extra degrees in February sounds swell, but unfortunately the side effects from rising global temperatures are potentially terrible for almost everybody. The poorest people in the world tend to live near the equator, and more heat is particularly problematic for them. The polar ice caps appear to be melting quickly and threatening seaside cities from New York to Hong Kong with the prospect of severe flooding. And higher ocean temperatures may create more volatile, stormier weather worldwide.

  Temperatures do fluctuate for many reasons, but that doesn’t change the fact that a colossal increase in carbon emissions could still radically affect the weather. Humanity has spent millennia adjusting to our current environment. If our carbon emissions radically alter that environment, the costs may well be enormous. The potential risks from a different climate make it reasonable for the world to take significant action to reduce the growth of carbon dioxide emissions. Among other things, that means favoring construction in areas that are greener and reducing building in areas that are more brown.

  Dirty Footprints: Comparing Carbon Emissions

  Matthew
Kahn and I have put together a carbon inventory of new housing throughout America. We wanted to determine the amount of carbon emissions that come from building a typical new home in different parts of the country, so we based our estimates primarily on homes built over the last two decades.

  In 2006, the United States produced about 6 billion metric tons of carbon dioxide, which doesn’t include the emissions related to the goods we import from elsewhere on the planet. That figure represents about one fifth of total world carbon dioxide emissions, more than any other country except China and more than the amount emitted by Europe and Latin America. Together, homes and cars account for about 40 percent of an average household’s output and also about 40 percent of America’s and 8 percent of the world’s carbon footprint. About 20 percent of America’s carbon dioxide emissions are related to residential energy use, and almost another 20 percent is associated with our motor vehicles.

  Using a gallon of gas produces about twenty-two pounds of carbon dioxide, if you factor in the carbon used in refining and distributing gasoline. An average family in the United States buys about a thousand gallons of gas a year, which is associated with about ten tons of carbon dioxide. It may be easier to imagine American families buying more fuel-efficient cars than giving up on car-based living altogether, but historically the bulk of variation in gas usage among various people over various periods of time comes from total miles traveled, not from fuel efficiency. Cars now get, on average, about 22 miles per gallon, and the big difference is whether you drive three hundred miles per year or thirty thousand, which depends on whether you live in a city or a suburb.

  Kahn and I found that area density and distance to the city center are both strongly associated with gasoline usage. The average household living in a census tract with more than ten thousand people per square mile uses 687 gallons of gas per year, while the average household living in an area with fewer than one thousand people per square mile (about one household per acre) uses 1,164 gallons of gas per year. The density of one’s home neighborhood matters because most car trips aren’t commutes downtown. People drive millions of miles to buy groceries, to go out to eat, and to pick their children up at school. The density of stores and schools in an area determines the average distance of those trips. In a city, you often walk to a restaurant. In a low-density area, eating out might entail a twenty-five-minute drive each way.