global warming. The federal government has signed on. The Obama administration has told metropolitan areas to include land-use regulations in the transportation plans that federal law requires them to update every five years. Washington is also giving communities “livability grants” aimed at promoting high-density development.
As a result, cities that are far removed from San Francisco in a political sense — Des Moines, Iowa, and Lafayette, La., for example — are considering similar land-use restrictions.
Advocates argue that the demand for single-family homes is about to drop as retiring baby boomers and up-and-coming millennials will prefer to live in mixeduse neighborhoods with high densities and easy pedestrian access to stores and entertainment.
This claim isn’t supported by people’s actual behavior. The vast majority of population growth continues to be in low-density suburbs. Surveys of millennials show that more than three out of four aspire to live in a single-family home with a yard.
The data also show that crowding people together isn’t really effective at reducing greenhousegas emissions or addressing other urban concerns. Population densities in the San Francisco-OaklandSan Jose urban areas have already grown by nearly 60 percent since 1990, yet per-capita driving still has increased.
Even under planners’ most optimistic projections, Plan Bay Area will have negligible effects on carbon-dioxide emissions: The draconian land-use changes will reduce emissions by only about threequarters of 1 percent.
In contrast, improved fuel economy, already mandated by the state of California, is projected to reduce per-capita emissions by more than 30 percent in the coming years.
Other transportation programs, such as van pooling and giving drivers incentives to use electric cars, are expected to reduce per-capita emissions by nearly 3 percent more.
As Americans consider the future growth and development of their communities, the Plan Bay Area debate should offer a message of caution. Forcing people to live in crowded “stack and pack” housing developments curtails freedoms without substantially curbing greenhouse gases.
There are many ways to reduce emissions that are genuinely cost-effective, some of which — such as making cars and homes more energy-efficient — could actually pay for themselves in the long run. In contrast, decreeing radical lifestyle changes for average Americans is expensive, intrusive and ineffective — squandering the political and financial capital needed for real improvement in environmental quality and our quality of life.