The planet's biggest problems have to do with sustainability, environmental decline, global poverty, disease, conflict and so forth. Really, they're all interconnected - it's one big problem, which is that the way we're doing things can't go on.

By fundamentally changing how we design the places and systems that enable our daily lives, we can slash emissions way beyond the immediate carbon savings - because our own personal emissions are just the tip of a vast iceberg of energy and resources consumed far from our view.

We have to craft new political realities, not only in places like India, Afghanistan, Kenya, Pakistan, but here at home as well. Another world is possible.

There's no law of physics that says we have to be an unsustainable society - in fact, quite the opposite. The planet's ready to work with us if we're ready to think differently, but we do have to make that jump and start to do things in new ways.

If mass media, social isolation in the suburbs, alienating workplaces and long car commutes create a bunker mentality, the Internet does the opposite.

To be young and aware is to know you’re being lied to; to know that a bright green future is possible; to know that we can reimagine the world, rebuild our cities, redesign our lives, retool our factories, distribute innovation and creativity and all live in a world that is not only better than the alternative, but much better than the world we have now.

The denser places get, the lower the amount of energy people use to get around it.