Want to grow the economy? Shrink your city's emissions.
In tough times, some of us see protecting the climate as a luxury, but that's an outdated 20th-century worldview from a time when we thought industrialization was the end goal, waste was growth, and wealth meant a thick haze of air pollution.
Cities and urbanization are the story of the 21st century. Already, most of us live in cities. Over the next 40 years, though, we'll ride a building boom unlike anything humanity has ever seen, or may ever see again, as the world's cities swell by billions. Cities at the center of this demographic revolution will be utterly changed.