Fig. 10. Energy intensity changes with changes in per capita (cap) income for China, India, Japan, and the USA. Historical data for the USA since 1800 are presented. Data are converted from domestic currencies using market exchange rates (mer). GDP stands for gross domestic product. Source: Nakicenovic et al. (1998). From "Ecosystems and Human Well-being: Scenarios, Volume 2" by Steve R. Carpenter, et al., eds. Copyright (c) 2005 Millennium Ecosystem Assessment. Reproduced by permission of Island Press, Washington, D.C.