America’s Water Supply Challenge: Adaptation to Future Population Growth and Climate Change

Abstract:

Water shortages, and the prospect of such shortages, have been repeatedly faced and addressed as population and economic growth placed increasing demands on available water over the past century. Such challenges have been most common in arid areas, but also have been encountered in some more humid portions of the US during times of drought. The challenges have been met using a wide range of adaptation measures, from large infrastructure projects (e.g., major trans-basin diversions) to alterations in local water prices (e.g., increasing block pricing). The future may bring even greater adaptation challenges as, in addition to continued growth in population, climate change will reduce water supplies in many locations. In this study we report on the relative importance of changes in demand versus changes in supply in causing projected future shortages in basins throughout the contiguous U.S. under different sets of socioeconomic and climatic conditions. We then examine the degree to which projected shortages can be avoided through adaptation. The adaptations examined include reductions in demand of major water use sectors, alterations in water management infrastructure, and inter-basin water transfers.