Tuesday, September 30, 2008

When "open space" is bad for the environment

In the East End of my hometown of Portland, Maine, the city is now entertaining a proposal to demolish an abandoned elementary school and build new mixed-income housing and a park in its stead.

I'm all for the idea: building forty new, energy-efficient units of housing in an urban neighborhood will reduce households' dependence on oil-burning automobiles for transportation and fuel-burning furnaces for heat. Especially when the families who would live here would otherwise have to drive 20 to 30 miles out into the suburbs to find a home for a comparable price.

As an environmentalist, then, I have to take issue with one major element of the proposed project: the proposal to set aside nearly half of the site for a park.

To be clear: parks are definitely necessary for a successful urban environment. Most parks provide important ecosystem services, like cleaning the air, filtering stormwater, and providing wildlife habitat, in addition to making the city a more pleasant habitat for humans.

But this site happens to be two blocks away from two of Portland's biggest and most successful open spaces already, so the marginal environmental benefit of a new park is pretty small. In comparison, the proposed housing is providing more important environmental benefits: namely, a big reduction in forty households' energy use, and reduced development pressure in Maine's rural suburbs. What if, by sacrificing a portion of the proposed park, we could realize a big reduction in fifty households' environmental impact?

Building more housing on an already-developed site in Portland will also save acres of forest or farmland from being bulldozed into new subdivisions out in the suburbs. In other words, a small sacrifice in open space here would create a substantial net gain in open space regionally. And more housing here would also reduce the amount of public subsidy this project would require, and free up more funds for affordable housing elsewhere in the city.

We need to ask ourselves this: in a neighborhood that already has so much access to parks and open space, should we really be making all of these financial and ecological sacrifices for another patch of lawn?

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