It's not just enough to survive. We've got to make something better than what we've got.

Cabbies in particular seem to like discussing the fate the Earth.

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.

I think there's a gigantic generation gap in terms of how people understand the Internet and how much they think technology is an important factor in social change.

Cities generate most of the global economy, and most of its energy use, resource demands and climate emissions. How we build cities over the next decades will largely determine whether we can deliver a bright green future.

Deep walkability describes a city that is built in such a way that you can move from one area to another on foot, on bicycle, on transit and have an experience that remains a pleasant one, that you feel you are welcome not just in the neighborhood but moving between neighborhoods.

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.