We are coming to the end of an amazing millennium, during which the human population has increased twenty-fold, from about 300 million to 6 billion. Over the millennium our growth in energy exploitation has been almost beyond measure. For the first 800 years of the millennium we had access to relatively few energy sources and the amount generated was, by current standards, slight but mostly renewable. Since then, the growth of industrial capitalism has called into being, at exponential growth rates, massive energy markets and enormous technical advances in energy sources, conversion and motion; first coal and steam, then oil, electricity, nuclear, and so forth. Such was this growth that in the USA this century the energy required to keep the American economy functioning has grown over a thousand-fold (Lapp 1973). During the twentieth century the energy released by our technology, and used by our productive forces generally, created an unprecedented level of wealth whose benefits, however unevenly, flowed through society and around the world. So dazzling were these benefits that their costs went for a long time unseen, or ignored. Almost against our will these costs forced themselves on our attention. Because most of the growth was due to the use of fossil fuels, localised pollution and extraction damage were first noted. Next, concern was expressed that fossil fuel resources would eventually be depleted (Meadows et al. 1972). It seemed, however, that there was always a technological solution-for example, nuclear power; human ingenuity was inexhaustible, and thus growth could continue unabated as it had over the last thousand years. That comforting belief dominated policy thinking (Simon and Kahn 1984) until the extent of climatic anthropogenic change became increasingly apparent over the last decade-and-a-half. Governments began to sit up and take notice and sustainability entered the policy lexicon (World Commission for Environment and Development 1987).