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Studies say suburbs, not cities, help fight global warming
by Don C. Brunell
President, Association of
The debate over global warming is turning some long-held truths upside down. For example, suburban sprawl may be a good thing after all.
Conventional wisdom says densely-populated cities are more energy efficient and better for the environment, while suburban development eats up precious open space and creates miles of polluting traffic snarls. But recent studies show that cities use disproportionately high amounts of energy and add to global warming, while suburbs do not.
This information comes from authors Joel Kotkin and Ali Modarres, who reviewed studies of cities around the world, including Beijing, Rome, London, Tokyo and Los Angeles.
The authors say the culprit is hardscape miles of impervious pavement, sidewalks, buildings and glass that reflect heat back into the atmosphere. In addition, these urban heat islands increase the need for air conditioning, which adds to energy consumption in cities. Ironically, air conditioning systems themselves generate heat, necessitating even more air conditioning. While street trees may provide a little relief for urban pedestrians, they can do nothing to cool a sea of tall buildings.
A 2006 article in the New Scientists magazine noted that cities can be up to 11 degrees warmer at night and a study of Athens featured in the journal Climatic Change suggests that the ecological footprint of the urban heat island can be up to twice the size of the citys political borders. These findings have been confirmed by recent studies out of Australia and Greece, as well as studies of U.S. cities, that document the temperature difference between highly concentrated central cities and their surrounding areas.
In contrast, lower-density suburbs integrated into the environment create less heat; in fact, it can take only a double-paned window to reduce energy consumption in a two-story house, and shade trees reduce temperatures even further in these smaller buildings.
Weve all experienced this first-hand. Walking on a sweltering city sidewalk on a summer day can bring you close to heat stroke. Drive just a few miles outside the city and the air is noticeably cooler.
Ah, but what about the pollution from all those drivers commuting to city jobs? The answer is to put the jobs closer to these communities.
Thats the principle behind planned communities like DuPont, north of Olympia.
DuPont began in 1906 as a company town owned by the DuPont Company. After the DuPont plant closed in 1976, Weyerhaeuser Company bought the surrounding 3,200 acres and ultimately embarked on an experiment in New Urbanism by creating a planned community called Northwest Landing.
Today, Northwest Landing is part of the City of DuPont. Anchored by major employers like Intel and State Farm Insurance, the community features historic Craftsman architecture in its homes and businesses, tree-lined streets and large parks. In 1995, it was named Best Master Planned Community of the Year and in 1997, Weyerhaeuser and designer Calthorpe Associates were honored by the U.S. Environmental Protection Agency for promoting smart growth principles such as pedestrian-centered communities with trails, businesses and public transit in close proximity to homes.
Planned communities are now common as developers, elected officials and residents embrace the principle that putting jobs and services close to homes and parks is better for the environment and produces a better quality of life.
As Washington and the Puget Sound region, in particular continues to struggle with the issues of growth and traffic, it is helpful to remember that the answer is not a choice between cities and suburbs but a careful balance of both cities and suburbs. Well-planned cities with roof-top gardens, open space and energy-saving technology can help limit heat pollution. Well-planned suburban communities with nearby employers, services and open space can make responsible use of outlying areas while preserving special places and agricultural land.