Writing for Grist, David Roberts argues that dense environments enable more efficient uses of resources, and the rise of information technology is helping to improve that efficiency.
"To say that density is green is not to say that all cities are green in all ways. (Obviously!) It is rather to say that when we look at pathways to radical, non-incremental change in our resource efficiency, all roads lead back to density. Nothing else has as much potential.
Consider: What's the main barrier to sharing more stuff and owning less? Well, it's a pain in the ass. Buying stuff is easy; indeed, the best minds in America are devoted to making it easier. But coordinating with other people to share stuff is time-consuming and often inconvenient. The main barrier to sharing is transaction costs. Density, bringing people into close physical proximity, is one way reduce those costs. Another is information technology. The two together make a modern, bright green city."