By Katherine Salant
Saturday, May 3, 2008
Can a new house reduce your ecological footprint?
An ecological footprint is a way of quantifying human impact on the earth. The originator of the concept, environmentalist Mathis Wackernagel, sees it as a way to help average people wrap their brains around an overwhelming amount of data.
Wackernagel converted all the earth's resources into a single unit of measurement, productive hectares of land. He terms that a global hectare. Then he calculated each person's share. That's the ecological footprint. With 6.6 billion people on the planet, the average stands at 1.8 global hectares per person. (1.8 global hectares equals 2.2 acres.)
The size of an average American's ecological footprint, however, has ballooned to 9.6 global hectares. If everyone on earth lived like we do, we would need five planets, clearly an unsustainable proposition. Scaling down to a "one-planet lifestyle" would require many changes.
When it comes to housing, size might seem to be the main issue. However, it's not as big a factor as you might think. Where you live and the type of transportation you use are just as important. If you have to drive to every activity outside your house, transportation takes up a significant share of your ecological footprint.
Of the choices available to new-home buyers, one of the smallest footprints could belong to a house in a New Urbanist community -- that is, one that follows the planning philosophy that models new suburban developments on older, walkable city neighborhoods. With its mixed-use land planning, shopping areas are within walking distance of most houses, so residents can use their cars less. When such a development adjoins public transportation, many two-car households get rid of one car.
To achieve true one-planet living, however, requires more. Fossil fuels would not be used, so the energy for heating, air conditioning and electricity would be produced by on-site renewable sources. To conserve local water sources, rainwater would be stored, treated and recycled. To the extent possible, building materials would be locally manufactured with recycled content.
Achieving all this community-wide would be considered impossible by most land developers and home builders. But it has been done in England by the BioRegional Development Group, which is now working with a U.S. developer.
That developer, Codding Enterprises, based in Rohnert Park north of San Francisco, is in the final planning stages of what promises to be America's first one-planet-living community, Sonoma Mountain Village. Construction is expected to begin next year and end in 2021. The eventual population is projected at about 5,000.
From a distance, Sonoma Mountain Village will appear to be a typical New Urbanist town, but close up, a visitor will see significant differences, said Geof Syphers, Codding's chief sustainability officer.
At 35 units to the acre, the housing density will be comparable to that in older neighborhoods such as Georgetown. Fifty stores and small businesses will line 10 blocks in the town-square area.
To attract an economically diverse population, more than half of the 1,900 housing units will be multifamily condominiums, senior housing, rental apartments and affordable housing. The 900 single-family houses will range from 500-square-foot cottages to conventional 3,000-square-foot, four-bedroom models. The average will be 1,400 square feet.
The one-planet aspects of Sonoma Mountain Village will be less obvious. Heat, hot water and electricity will be produced on site with renewable sources. Roof-mounted solar collectors will provide hot water. Passive solar design features that tap the warmth of the sun will produce most household heat; the cloudy weather backup heating will be provided by a community-wide grid of geothermal heat pumps that capture the warmth of the earth. Electricity will come from solar photovoltaic panels, which will be arrayed on the roofs of all the commercial and some residential buildings. The combined output of that system will be shared among the households and businesses.
Cisterns throughout the project will collect and treat rain to be used for irrigating the landscape during the nine-month dry season.
To give the local economy a boost and reduce the environmental impact of shipping materials across the country, some major construction components, including cabinetry and framing, will be produced by local firms. Codding is also using recycled and reused materials to an impressive degree.
The firm opted for steel framing instead of wood because there is less waste, and the framing will be made from recycled automobile parts.
Every front door will be made of reclaimed wood salvaged from local rivers and lakes by a firm that also makes the doors. The flooring for the front porches will be recycled, lightweight, fly-ash concrete. Unlike conventional concrete that is made with energy-intensive Portland cement, fly-ash concrete is made with the waste that accumulates at coal-powered electric plants.
For many people, though, the most interesting aspect of this project could be the social engineering. The company said it wants to create a sense of community and a consensus for living within a smaller ecological footprint.
To do that, it needs to foster casual socializing. Each neighborhood will have a New Urbanist treatment: narrow streets lined with wide sidewalks and porches. In many cases, kitchens will overlook the street so that a resident working at the sink can wave to passersby or chat when windows are open. Each neighborhood will have a pocket park with public art.
To reduce car use, the town center will offer essential services as well as entertainment venues, a movie theater, restaurants, a bakery and a daily farmers market. For commuting, residents can choose carpools, buses or a shuttle service to the local train station. For those willing to eschew a car altogether, the developer will organize a car-share club that lets members rent hybrid or electric cars by the hour.
Katherine Salant can be contacted via her Web site, http://www.katherinesalant.com.
© 2008 Katherine Salant