From Witold Rybczynski:
... LEED (Leadership in Energy and Environmental Design), which has become the standard in the United States, award points based on a checklist—daylighting, water recycling, solar panels, bicycle racks, and so on.
... Yet a checklist approach has drawbacks. It tends to focus attention on unusual features, such as green roofs. Growing grass on a roof is definitely photogenic, but it is not as energy- and cost-efficient as simply painting the roof white (see “The California Experiment,” page 66). And checklists—even weighted checklists—may produce misleading results. Both a suburban office campus and an urban high-rise office building, for example, can receive a high rating. As David Owen points out in his forthcoming Green Metropolis: Why Living Smaller, Living Closer, and Driving Less Are the Keys to Sustainability, in the office campus, people work in sprawling buildings and drive between them; in the high-rise, people work in a compact building, use elevators (which are inherently energy-efficient, since they are counterweighted), and walk to lunch.
... 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.
Yet urban density itself can't be all of it. Think Bangkok or New Delhi with air-conditioners running 24/7 and cars jammed in the streets. The city itself has to be dense as well.