ABSTRACT
In 1992 William Clark published the results of a twelve-country historical analysis based on the Ehrlich framework (1992). It was a revolution in energy— the rise of fossil fuels— that brought people the urban industrial society that promises a better life but also poses major challenges for sustainability. To achieve the economic development that all countries now desire and to provide for the ever increasing numbers of people on the planet requires more energy. Energy consumption grows more rapidly than wealth production in the early stages of development. But it is also true that in the process of development a peak is reached in levels of energy consumption per unit of wealth; and from that point technology becomes more efficient, and the amount of energy required to produce an extra unit of wealth declines. The product mix of industrial consumption can vary greatly and can become an element of national planning.
