Doubling the size of a city increases wealth and innovation by about 15 percent, but it also increases the amount of crime, pollution, and disease by roughly the same amount. Apparently, the good and the ugly come hand in glove, an integrated, almost predictable, package. A person drawn to the city by innovation, a greater sense of “action,” and higher wages can also expect to confront an equivalent increase in smog, garbage, theft, stomach flu, and AIDS.
In contrast, the social networks that underlie the “superlinear scaling” of wealth creation, innovation, crime, and pollution behave in exactly the opposite fashion: The bigger the organization, the faster the pace of life. In big cities, disease spreads more quickly, business is transacted more rapidly, and people walk faster — all in approximately the same systematic, predictable way (the same ~15 percent rule).
In contrast, in social organizations where growth is driven by superlinear scaling, growth is unbounded, never reaching an “asymptotic” stable state, and proceeding at a rate that is faster than exponential. To sustain such growth in the light of resource limitation requires continuous cycles of paradigm-shifting innovations such as the discovery of iron, steam, computation, and most recently, digital technology. Indeed, the litany of such breakthroughs is testament to the extraordinary ingenuity of the human social mind when it comes to overcoming resource limits. There is, however, a serious catch: Theory dictates that the time between successive innovations must get shorter and shorter. So if we insist on continuous growth driven by wealth creation, not only does the pace of life inevitably quicken, but we must also innovate at a faster and faster rate!
The challenge is clear: The key to long-term sustainability of the planet lies in applying a scientific lens to cities, with the goal of understanding their dynamic structure, growth, and evolution.