Looking backward to look forward: water use and economic growth from a long-term perspective

Recent research has examined the relationship between natural resources and economic growth. Considered vitally important, not only for humanity's well-being but also for the integrity of the ecosystem, the relationship between water use and economic growth has nevertheless traditionally attracted little attention by analysts. This article studies water use trends from 1900 to 2000 throughout the world and their relationship to the main determinants of economic growth. To do this, we first analyse water use trajectories. Second, to proceed with the determinants of water use, we reformulate the Ehrlich and Holdren's impact, population, affluence, technology (IPAT) equation (1971), decomposing water use trends into changes in economic demands and in water use intensity on the basis of a decomposition analysis. Finally, a simple scenario analysis is conducted, to project future water use trends under different economic, demographic and technological assumptions.The empirical evidence shows that economic and population growth have been crucial in explaining the increase in water use over the past 100 years, with significant regional differences. Nevertheless, the decline in water use intensity has been responsible for a significant reduction in the growth of total water use.