Cities are responsible for the vast majority of the creation of the economy. They're also places into which we pour the vast majority of resources, the vast majority of energy and the places where a huge percentage of the decisions about how systems are built and how products designed, etc., happen.

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.

Cities offer us powerful leverage on our most stubborn, wasteful practices. Long commutes in our cars, big power bills from our energy-hogging buildings, shopping trips to buy stuff that'll spend a few short months in our homes and long centuries in our landfills.

Carbon zero simply means that the emissions you are releasing either are zero or balance out to zero.

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

For most people, using the Internet broadens their sense of who 'we' is and actually ends up leaving us in a place of greater compassion and understanding. It leaves us more connected to a larger group of people and more at one with a lot more people in our community.

Copenhagen has done a remarkable job creating streets that are focused on bicycles and pedestrians.