City living can be more sustainable than the suburbs. Governments should find ways to incentivize urban density. Credit: Hans Kylberg via Wikimedia Commons

Last week, Conor Dougherty and Brad Plumer filed an illuminating piece in the New York Times titled "A Bold, Divisive Plan to Wean Californians From Cars." According to these reporters, the policy is:

"…an audacious proposal to get Californians out of their cars: a bill in the State Legislature that would allow eight-story buildings near major transit stops, even if local communities object. The idea is to foster taller, more compact residential neighborhoods that wean people from long, gas-guzzling commutes, reducing greenhouse-gas emissions."

The proposal is built on the knowledge that people who live in apartments and can walk to work or shop use less energy than people who live in suburban sprawl style development; that is true. We should do all we can to encourage urban population density, which is one of the themes of my new book, The Sustainable City. Density provides economies of scale that enable the use of expensive high-tech infrastructure for energy, transportation, water filtration, sewage treatment and waste management. But there are no shortcuts to urban sustainability. It needs to be built on positive reinforcement and mass social and cultural change. In America, a government edict will not work. If a community doesn't want , government should not make them accept it. But if a community won't accept greater population density, they should not receive the benefit of a new train station either. Instead, we should build a train station where a community is interested in building a town square with higher densities than the surrounding area. In fact, we could have the same rule for new highway exits. Government should provide incentives for density; it should not try to mandate it.

The idea that sustainability requires unwanted lifestyle changes dooms the politics of sustainability. We need to approach sustainability positively. Sprawl development was not an accident. Yes, people liked the idea of more living space and their own backyards, but government built highways that subsidized their transportation, made mortgage interest and property taxes deductible, and developed federal insurance for home mortgages. People were paid to move to the suburbs. Suburban development was not an accident, but a national . Most suburbanites got a lot of what they hoped for, but they also got traffic, dependence on more and more cars, and often long commutes to and from work.

Young people are gravitating to cities for the entertainment, convenience, excitement and, in some cases, for the opportunity to live sustainably and consume fewer finite resources. The trick will be to keep them in cities when they start to raise families. Older people are returning to cities for the elevators, taxis, social engagement, entertainment and health care. California's legislature should develop a more sophisticated design to encourage densely settled communities. The policy design should be less blunt than a sledgehammer forcing communities to accept apartment buildings.

Dougherty and Plumer discuss positive approaches in their article and observe that:

"California tried an incentive approach to density with the Sustainable Communities Act, a sweeping bill passed in 2008. But some experts say it did not go nearly far enough to change the state's urban sprawl or car culture."

California's car culture and desire to maintain single family housing through local zoning rules is so extreme that there is a severe housing shortage and its residents devote a higher proportion of their income to housing than most Americans. By definition, the policy approaches employed so far have not worked. It will take more to get people out of their cars and back on their feet.

One approach might be to find communities that are willing to encourage higher density in return for new mass transit lines. Communities located beyond existing lines could be approached to see if they are interested. Bus rapid transit like the system in Bogota, Columbia, or light rail like Portland, Oregon, or Jerusalem, Israel are relatively lower priced ways of building mass transit lines. Renters in high density communities might receive an income tax deduction for living in apartments. A variety of creative financing schemes and new forms of transportation could reduce auto miles travelled per capita–without inconveniencing people or impairing their quality of life.

If we are going to reduce the environmental impact of our way of life, people need to be positively attracted to that way of life. Punitive policies are also unlikely to work in the long run. Apartments might be built and then only filled at a financial loss. Under those conditions, developers and the housing market will cause the policy to fail. The counter-argument is that California's housing shortage is so acute that no housing development in California can fail. Perhaps, but the idea that sustainability requires individuals and communities to accept outcomes they do not want will become more deeply ingrained in our political life.

A better approach is to make urban living more affordable and attractive. Improve the schools so that families do not gravitate to the suburbs to raise children. Improve parks, mass transit and use new technologies to improve air quality. Provide incentives to locate assisted living facilities for the elderly in areas with higher population density. In sum, use public policy to encourage the private sector to invest in cities.

As a resident of New York City, I don't need to be sold on the lifestyle advantages of city life. I have benefited from New York's rebirth in the 21st century. While our subway system needs reinvestment, our schools, parks and public safety have all improved dramatically over the past two decades. Most of my transit is by foot or by the subway. I live within walking distance of Riverside, Central and Morningside Parks. My wife and I enjoy the city's entertainment, restaurants, shops, cultural life and streets. I am fortunate in owning a summer bungalow a few blocks from Long Island's south shore and I live close enough to the mountains that I can easily experience nature when I get tired of the city. I enjoy city life, but it's not for everyone. Our public policies should not be designed to compel lifestyles that people do not want.

Given America's pattern of land use development, increased density can only be one element of the sustainability solution. Personal transportation will always be part of the American way of life. We need to invest in the technology to make electric vehicles cheaper and better than those based on the internal combustion engine. We need to build an energy system dominated by renewable energy. We will require better technology to ensure that suburban development reduces its carbon footprint. Government can push density, but it also needs to invest in the technology and infrastructure that make suburban living more sustainable.

Perhaps because environmental policy is heavily influenced by physical and natural scientists, there is an attempt to "solve" environmental problems. Public policy is not like solving an equation or testing a hypothesis. It is not neat and rational. It is messy, incomplete, partial, and remedial. We don't actually solve public policy problems, we make them less bad. The air is cleaner in New York today than it was in 1970, but it is far from pristine. Crime has been dramatically reduced here, but it will never be eliminated. Sustainable cities will be built gradually over the coming decades. The process can be accelerated with sophisticated, carefully designed public policies. California needs more renewable energy, more electric vehicles, and as much increased density as they can attractively design. But people should be encouraged to live this way, not compelled to. For a sustainable lifestyle to truly take root, it needs to be seen as a more interesting, exciting and fashionable way of living than today's typical suburban living.