ABSTRACT
Cities grow ever faster. Cities grow ever bigger. Imagine a middle-sized town of 200 000 inhabitants. With so many people the world's urban population increases in one day. In one month this growth is almost 6 million and in a year around 70 million. This implies that rural areas must supply escalating amounts of food, energy and many other commodities to towns and cities. Mass flows grow rapidly, distorting ecosystems, as do markets, distorting ages-old social systems.
