Urbanization is happening rapidly. Is this good or bad?

"I view great cities as pestilential to the morals, the health and the liberties of man."

Thomas Jefferson was not a fan of cities, and neither were some of this country's greatest thinkers, including Emerson, Thoreau, Henry James, and Frank Lloyd Wright, who called the American city "a parasite of the spirit." More recently, commentator George Will has gone so far as to call urbanization a liberal plot to rob people of their freedom. Globally today, for the first time ever, more people live in cities than anywhere else, and the World Health Organization estimates that by the year 2050, 70 percent of the world's population will be urbanites. If, like Jefferson or Will, you think this means that our morals, health and liberty are at risk, you're wrong. By many important measures, cities are dramatically better for the environment, the economy, and you.

Cities are smarter for the environment

Urban development is significantly more efficient with resources, because higher density yields lower waste. In December, a Berkeley study revealed that the average footprint for households in major urban areas is less than half the national average, while it can be twice the average in suburbs. New York, the largest U.S. city, is also the greenest by far for per-capita consumption. Its carbon emissions are less than a third the national average, and electricity use is 75 percent lower than Dallas. Because walking and public transit are popular, gasoline consumption approximates U.S. levels from the 1920s.

Denser land use also preserves more area for natural development. According to estimates, a single acre of forest absorbs enough carbon and produces enough oxygen to meet the annual needs of 18 people. Reforesting the land of a single Big Box retail site can nullify the environmental footprint of over 300 people.



Density and walkability promote human and environmental health. Manhattan's carbon emissions are less than a third the national average, its obesity rate is less than half the national average. High Line, New York. Credit: iStock.com/ © Ferran Traité.

Cities are smarter for the economy

Cities are economic engines. Various studies show that as population density rises, so do wages and productivity: a few years ago, the Federal Reserve Bank estimated that for every 50-percent swelling in density, productivity grows by 2-4 percent. A 2011 Brookings Institution report reveals that in 47 out of 50 states, just one or two metropolitan areas account for the majority of the state's GDP. In each of 15 states, one city alone accounts for the bulk of economic output.

Economist Edward Glaeser explains:

Cities bring opportunities for wealth and for the creative inspiration that can result only from face-to-face contact with others. In fact, the crush of people living in close quarters fosters the kind of collaborative creativity that has produced some of humanity's best ideas.

For example, research correlates higher employment densities with higher rates of patent applications, while "intellectual spillovers" drop off precipitously when companies are located more than a mile apart, according to studies. Cities breed innovation by putting people with diverse views in close proximity. This is why urbanist Richard Florida calls cities "cauldrons of creativity."

Cities are smarter for you

Because higher density and mixed uses promote more casual exercise, larger cities often are healthier. A Georgia Tech study indicates that every 30 minutes per day spent in a car increases the likelihood of obesity by three percent, whereas walkable, mixed-use neighborhoods decrease it by seven percent. New York is the most walkable city in the country, with an average Walkscore of 88/100 and the highest percentage of non-car commuters (67 percent). As a result, Manhattan's obesity rate is only 15.4 percent, less than half the national average. According to the CDC, annual medical costs are $1,429 higher for the obese, so Manhattan's thinner population could save its 1.6 million residents nearly half a billion dollars every year.

According to a 2010 Gallup poll, the longer your commute, the lower your well-being. In 2011, Swedish researchers found that people who commute by car more than 45 minutes per day are 40 percent more likely to divorce. Decentralization, fragmentation and longer commutes can significantly hinder the ability to form community ties, research reveals. Regular social interaction can increase life expectancy, while isolation can be more harmful than lack of exercise, obesity, alcoholism or smoking.

Conventional wisdom maintains that big cities are more dangerous, but research says no. A 2009 University of Virginia report demonstrates that higher density leads to few traffic-related deaths. Other analysis supports Jane Jacobs' 50-year-old supposition that more populous neighborhoods tend to deter violence by putting more "eyes on the street." In the 1990s, New York City's population spiked, growing nearly 10 percent that decade, while the crime rate dropped by more than half -- double the national decline. The most densely populated place in the country, Guttenberg, NJ, holds nearly 59 thousand people per square mile -- over twice the density of New York -- yet, its crime rate is less than a third the national average. By contrast, while Detroit has the nation's highest crime rate, it doesn't even appear in the top 100 densest municipalities. In fact, there is no large metropolitan area that is in the top 10 lists for both crime and density.

Various attempts to connect city life with adverse effects on well-being have proven to be inconclusive, since those effects could be linked less to density than they are to the quality of environment. In fact, surveys reveal that the most important factor contributing to personal happiness is how attractive we consider our community to be. Richard Florida calls it "the beauty premium."

With the benefits of urban life becoming clearer and clearer, it's no wonder that people are showing a strong preference for it. In December, the American Institute of Architects released a report indicating a "pronounced shift" in the housing market over the past decade, with more and more demand for higher density, walkability, mixed uses and access to public transit. Couple these trends with abundant recreational opportunities, urban agriculture and forestry, green infrastructure, and well-designed places, and the future of cities looks very bright.

Lance Hosey, FAIA, LEED AP, is Chief Sustainability Officer with the global design leader RTKL. His latest book is The Shape of Green: Aesthetics, Ecology, and Design (2012). He is a member of the American Institute of Architects Committee on the Environment.