ABSTRACT
The first part of this article describes the discontinuity in the trajectory of human development represented by the transition from pre-industrial rural society to modern urban life in the nineteenth and twentieth centuries. As we will see, this transition was directly related to changes in energy metabolism, namely the switch from the use of renewable energy inputs to fossil fuels as primary energy source. The total dependence of modern urban society on fossil energy as primary energy source brought about an important change in the role of the city in society. Whereas in pre-industrial rural society cities could exist only by the mere grace of the surplus produced in rural areas, in post-industrial urban society cities are in charge of directing the flows of fossil energy in the entire society inclusive of rural areas. This provides to cities the required degree of freedom to become drivers of creativity and innovation.
