Witold Rybczynski is a terrific writer, and puts together the green case for cities in a short essay in the Atlantic, with a few digs at the green gizmo approach to sustainable design:
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.
He continues with a demolition job on most of the posts we have done on building materials and technologies:
via the late lamented edificial
Architectural journals and the Sunday supplements tout newfangled houses tricked out with rainwater-collection systems, solar arrays, and bamboo flooring. Yet any detached single-family house has more external walls and roof--and hence more heating loads in winter and cooling loads in summer--than a comparable attached townhouse, and each consumes more energy than an apartment in a multifamily building. Again, it doesn't really matter how many green features are present. A reasonably well-built and well-insulated multifamily building is inherently more sustainable than a detached house. Similarly, an old building on an urban site, adapted and reused, is greener than any new building on a newly developed site.
He is not saying that we all have to live in Manhattan, noting that the garden suburbs of the early 20th century, the streecar suburbs built around transit, were of sufficient density to support shopping, walkability and a denser fabric of urban life. Worth reading in the Atlantic.
More on density and cities:
Graph of the Day: Driving VS Residential Density
Tall Cities = Green Cities?
The Transportation Energy Intensity of Buildings