According to Witold Rybczynski (writing in The Atlantic), it's time to get serious about living sustainably. Currently, we do that by going out to buy the latest and greatest gadgets for saving energy. There's a much better foundation for accomplishing this goal of living sustainably:

The problem in the sustainability campaign is that a basic truth has been lost, or at least concealed. Rather than trying to change behavior to actually reduce carbon emissions, politicians and entrepreneurs have sold greening to the public as a kind of accessorizing. Keep doing what you’re doing, goes the message. Just add a solar panel, a wind turbine, a hybrid engine, whatever. But a solar-heated house in the burbs is still a house in the burbs, and if you have to drive to it, even in a Prius, it’s hardly green.

Instead of putting little Band-Aids on the big problem, Rybczynski argues that we ought to move back to the city. We would save much more energy by prohibiting spread-out low-rise buildings than by pasting solar panels on them. "A reasonably well-built and well insulated multifamily building is inherently more sustainable than a detached house." He advocates three or four story "walk-ups," which don't require elevators. These can create sufficient density "about 50 people per acre, to support public transit, walk ability and other urban amenities." Another important approach is to focus on the way we construct our commercial buildings. When we combine residences with commercial and institutional structures, buildings consume 48% of our energy, more than any other sector.