s142.
If a growing population is added in here, even greater improvements in such technology would be needed to stabilise the impact on the biosphere. The interaction between environmental impact, If See Paul Ekins, “Sustainability First”, in Paul Ekins and Manfred Max-Neef, eds. (1992), Real-Life Economics, pp 412–422, (specifically pp 418–419). For the famous debate on this, see Paul R. Ehrlich and John P. Holdren, “Impact of Population Growth”, Science, vol 171, 26 March 1971, pp 1212–1217, and http://tinyurl.com/p5vnt4s . See also M.R. Chertow, “The IPAT Equation and its Variants: Changing Views of Technology and Environmental Impact”, Journal of Industrial Ecology, 4, 4, 2001, pp 13–19; and R. York, E.A. Rosa and T. Dietz, “STIRPAT, IPAT AND ImPACT: Analytic Tools for Unpacking the Driving Forces of Environmental Impacts”, Ecological Economics, 46, 3, 2003, pp 351–365. environmental impact is to be held constant, and population is assumed to be constant, any advance in affluence must be offset by a matching improvement in technology (i.e., technologies which reduce environmental impact). If population increases—and especially if affluence increases at the same time—technological improvement must achieve extreme reductions in order to hold the impact constant. If the environmental impact is to be made to fall, the task of efficiency-improvements required of the technology must of course be more extreme—and more remote from reality. Population, the scale of economic activity and technology is summarised in the ‘IPAT equation’, by Paul and Anne Ehrlich: Impact = Population × Affluence × Technology.