Some people I've talked with who are into environmentalism and anarchism expect the future to be decentralized not just in politics, but in geography as well. They want to essentially undo urbanization and let people live in small towns and communities, in harmony with nature, and so on. I think this is absolutely the wrong way to go, both for ourselves and for the environment.
Here's an example of why:
This is a map showing carbon dioxide emissions per capita. Red is bad, pale green is good. Notice anything surprising about that map? The urbanized East is far greener per capita than the spread-out West. It takes a certain minimum amount of infrastructure to support people, and there are efficiency gains to be had by putting more people in less space.
High-density urban living, supported by technologically-mediated organic vegan farming and renewable energy, could maintain populations as high or higher than we have now while reducing our environmental impact.