How the world's wealthiest cities can beat back climate change.
"In the past people have tended to measure carbon footprints by measuring how many emissions we’re directly creating. But we live in a truly globalized economy. Many of the things we use in our everyday lives come from other places, and while the emissions may be released in another place – China, for instance -- they are in a really clear way the direct the result of our own consumption. So in the last few years, people have started trying to measure what’s called consumption-based footprints. Which is basically to say, everything we actually use in our lives, all of the stuff that we use, all of the materials and energy that go into the things around us, how many emissions are being produced."