urban metabolism
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maintained, there is ‘consumption of capital’ and therefore no sustainability42. Daly reiterates the need to ensure the ecosystem’s continuing ability to sustain the flow of materials and energy from natural sources through the entire human economy, then returning to nature as waste. In the context of ever-increasing anthropic pressure, linked to indiscriminate global production and consumption, the concept of circular economy responds to the concrete need for sustainable development. Circular economy The term Circular economy dates back to 1990, when it was used in a book by two British economists, David W. Pearce43 and R. Kerry Turner44, entitled Economics of Natural Resources and the Environment45. The two authors, basing their idea on reflections by the economist K. Boulding46, pointed out that the economy is not an open and linear system but a closed and circular one, as depicted in Figure 247. Daly H.E. 1996, Beyond growth: the economics of sustainable development, Beacon Press, Boston. 43 David W. Pearce OBE (1941 - 2005) Professor Emeritus in the Department of Economics at University College London (UCL). He specialised in and was a pioneer of Environmental Economics. 44 R. Kerry Turner (1948) associate professor in the School of Environmental Sciences and former professor of environmental economics and management at the University of East Anglia, UK. 45 Pearce D. W., Turner R. K. 1989, Economics of Natural Resources and the Environment, Johns Hopkins University Press. 46 Author of: The Image: Knowledge in Life and Society (1956) and Conflict and Defense: A General Theory (1962). He is also the originator of general systems theory. 47 Andersen M.S. 2006, An introductory note on the environmental economics of the circular economy, «Sustainability Science», n. 2, p. 136. 42
