Our cities have the potential to be a key climate change solution. Already they are hot-beds of innovation in local and global approaches to the nexus of sustainability and quality of life.  People who live in cities drive less, use less energy to heat, cool, and light their homes, and even their water and sewer lines are shorter and require fewer resources. (See related, “The City Solution.”)

But all of those advantages – and the ability to save more land for nature and agriculture – will be cancelled out if our cities are ringed with suburbs that are profligate in their use of energy and resources. In my laboratory – the Renewable and Appropriate Energy Laboratory (RAEL) — at