How do we make cities greener? Start by growing smarter

The video of my talk at Saturday’s “Greening Greater Washington” seminar at the Smithsonian is now available online:

Coincidentally, the Wall Street Journal contains an 8-page section today on how to make cities greener.

Most of it focuses on the traditional environmental subjects, like reducing trash, cutting down on rare metals, saving water and home weatherization.

Those are all very important, though in recent years the environmental debate has broadened to include the larger issues of land use and transportation. We use 20-25% of our energy on transportation alone, so no discussion of reducing ecological footprints can be complete without discussing transport.

The article says,

It wasn’t long ago that the idea of using “green” and “city” in the same sentence seemed absurd. Cities were considered a blight on the environment: energy-hogging, pollution-spewing, garbage-producing environmental hellholes. But in recent years, they’ve begun to be seen as models of green virtue. City dwellers tend to walk more and drive less than their suburban counterparts, and dense urban development encourages transit use. Apartment living generally means lower per-household energy use.

This is an important shift. Certainly more pollution and waste are created per square mile in cities, but that’s because they have more people; each individual person has lower impact in a city than outside. A fixed set of people is more sustainable the fewer acres they collectively use.

At one point, some viewed the ideal sustainable lifestyle as one where a small bubble of trees and grass surrounds each household. But instead, that just means a lot of heating and cooling energy is wasted to that bubble, and we spend far more energy moving among them.

Not everyone has yet come around to that view. During the Q&A for one of the panels, an audience member criticized a trend in Arlington where some property owners are enlarging their houses, or additional dwelling units or in-law suites to their homes. She said that is creating a less sustainable form of living.

If people just enlarge houses to accommodate a separate media room, that certainly doesn’t make the home greener, though the effect is probably small. However, if the change allows for more residents, such as more children, family members, or a second family, it’s one of the greenest things we can do.

In his talk, Chris Zimmerman noted that Arlington residents drive about 25-50% less per person on average than residents of Montgomery, Prince George’s, Fairfax, Loudoun and Prince William. I suspect that’s largely because they start their days much closer to their jobs, and also are far more likely to have transit options.

The day’s conversations included plenty of talk about improving stormwater treatment, weatherizing homes, and even the ways the Smithsonian cuts down on energy use by allowing more temperature variation in its exhibits where that won’t damage the artifacts, but the biggest focus looked at the overall shape of our region, its cities and towns, and the agricultural areas which are or aren’t preserved. The way we grow in the future is likely to be the most significant factor in how sustainable a region we have for generations to come.