Urban retrofitting: creating different sorts of spaces and uses out of places that are already there.

We get so little news about the developing world that we often forget that there are literally millions of people out there struggling to change things to be fairer, freer, more democratic, less corrupt.

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.

You don't change the world by hiding in the woods, wearing a hair shirt, or buying indulgences in the form of 'Save the Earth' bumper stickers. You do it by articulating a vision for the future and pursuing it with all the ingenuity humanity can muster.

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.

Clean air and water, a diversity of animal and plant species, soil and mineral resources, and predictable weather are annuities that will pay dividends for as long as the human race survives – and may even extend our stay on Earth.

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.