Environmentalists are DEEPLY and BITTERLY divided into two camps: the Greens and the Grays. And they're constantly fighting with each other. The Greens are fighting to save trees and stop housing and density from destroying green space in our cities and suburbs. The Grays are fighting for new buildings and denser housing, to stop sprawl from destroying natural areas beyond the city. They both proclaim to be environmentalists, and yet they are diametrically opposed on the same issue. What’s going on? Why is housing tearing them apart? And who’s right?