For many Americans, urban sustainability brings to mind images of solar panels, recycling bins and smart cars. Perhaps buying “green” products at the grocery store and biking to work once in a while enter the picture as well. There is much more to it than this, however. Urban sustainability means more than simply living our lives in a somewhat more environmentally benign way. It is about challenging assumptions and seeing the world — and our place in it — in a different light.
For centuries, cities have been viewed as the antithesis of nature. How could such places, so dirty and overcrowded, possibly contribute to a more sustainable future? Don’t cities consume enormous amounts of energy, food and water, much of which has to be imported from elsewhere? Don’t cities also generate enormous quantities of waste and pollution? The answer to both of these questions is “yes.” Indeed, the ecological footprint of a city is enormous. Ironically, it is just this relationship — lots of people squeezed into small spaces on the earth’s surface — that make cities more efficient and, in theory at least, more sustainable.
So what is it that makes city living more sustainable than life in the suburbs or in rural areas? A closer look at New York City explains why this is the case. First, packing a lot of people into small spaces has forced New Yorkers to build up instead of out. Building tall buildings not only permits the city to add floor space using the same amount of ground area, it induces residents to be more energy efficient. For example, stacking apartments saves energy in the winter because excess heat from one unit warms surrounding units.
Second, urban dwellers consume less electricity than suburbanites — about 27 percent less.
Third, high housing prices cause most people in New York to occupy small living spaces. Living smaller means people accumulate fewer material goods. Finally, New Yorkers drive less and so they consume less fossil fuel and generate less air pollution. In fact, 82 percent of employed residents in Manhattan walk, bike or take public transit to work. All that walking and biking does more than save energy; The average New Yorker weighs less than the average American and has a higher life expectancy.
That city living may hold the key to sustainability should come as welcome news. According to the 2010 census, 83.7 percent of Americans live in one of the country’s 366 metropolitan areas. Now here’s the bad news: When it comes to population density, New York City is the exception rather than the rule. In cities such as Nashville, St. Louis, Las Vegas, Phoenix, and dozens more, urban form was not constrained by physical geography. Moreover, it was influenced by the car, which has dominated transportation since the 1950s. Thanks in part to federal highway subsidies and housing policies, cities throughout the U.S. spread outward instead of upward. As more and more people swapped apartments in the city for detached houses in the suburbs our metropolitan areas “sprawled.” From a sustainability perspective, this has been a disaster. Urban sprawl has reduced population densities, eroded municipal tax bases and discouraged investment in urban infrastructure, including public transportation. Low-density suburban development has also dispersed employment, causing more people to commute by car, increasing fuel consumption, compounding congestion problems and adding to the air pollution load.
While numerous strategies have been employed to control sprawl — urban growth boundaries, greenbelts, smart growth, and so on — the problem has only worsened in recent years. According to James Gustave Speth, since 1970 average house size in the U.S. has increased 50 percent. Meanwhile, per capita electricity consumption has shot up 70 percent. Worse, 80 percent of new construction since 1994 has been “exurban,” occurring at the farthest reaches of the urban-rural interface. If we are serious about sustainability, we need to promote policies that discourage sprawl and encourage compact living. Greater density translates into more tax dollars, less driving and cleaner air.
“If the future is going to be greener, then it must be more urban,” writes Edward Glaeser, professor of economics at Harvard University. “For the sake of humanity and our planet, cities are – and must be – the wave of the future.”
Professor Geoffrey Buckley is an associate professor in the Department of Geography. His areas of expertise include historical environmental geography; resource conservation and management; and land use in North America and Appalachia.