Here’s an interesting tidbit from the ever-geekalicious Todd Litman: a chart comparing average impervious surface per household in urban vs. suburban settings.
As you can see, large single-family lots — the sort of homes that are surrounded by greenery — actually require the most pavement overall. Apparently, it takes an awful lot of road space to get a homeowner to and from that exurban McMansion. (Take that, sprawl!)
At the same time, even though dense cities are typically plastered with concrete, in the final analysis urban high-rises seem to rest lightest on the landscape.
This chart was taken from a new "Pavement Busters Guide" (PDF) with some pretty detailed recommendations for ways to reduce impervious surface area in cities and suburbs. Todd’s number one recommendation: educate decisionmakers. Sounds like a smart first step to me.