Reinventing cities for people and the planet

Cities are home to more people than ever before. In 1900, only 160 million people, one tenth of the world's population, were city dwellers. But soon after 2000, in contrast, half the world (3.2 billion people) will live in urban areas--a 20-fold increase in numbers. In this urbanizing world, cities hold the key to achieving a sustainable balance between the Earth's resource base and its human energy. Industrialization in developing countries has led to urban health problems on an unprecedented scale. Cities around the world affect not just the health of their people but the health of the planet. Urban areas take up just 2 percent of the world's surface but consume the bulk of vital resources. In this paper, the author shows that changes in six areas - water, waste, food, energy, transportation, and land use - are needed to make cities and the vast areas they affect better for both people and the planet. Cities can align their consumption with realistic needs, produce more of their own food and energy, and put much more of their waste to use.