In almost all city governments in America, the small group of people who don't want change are able to block change.

There’s more to being an environmentalist than occasionally signing an online petition and mailing your check to the Sierra Club. Really the most effective environmental actions you can take have to do with crafting your home and surroundings, your workplace decisions and your investment habits.

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.

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

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.

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.

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