Long-Term Water Projections and Climate Change

Model scenarios predict increased scarcity in the Middle East and India.

Image courtesy of Kay Ledbetter for Texas A&M AgriLife Research via a Creative Commons license.
Researchers have used a global climate model to assess future water demands in the agricultural, energy, industrial, and municipal sectors, concluding that freshwater availability may be insufficient in some regions.

The Science

Global freshwater use has grown over the past century from an estimated annual 580 km3 in 1900 to 3829 km3 in 2000, with continued growth expected in the coming century. The need for freshwater is likely to increase in the future as regions are subjected to more extreme climate conditions and rapidly growing demands in water-use sectors such as agriculture (crop production, irrigation, and livestock), municipal, and industry (energy and manufacturing).

The Impact

Researchers have concluded that (1) freshwater availability may be insufficient to meet all future water demands in some regions such as the Middle East and India and (2) many regions can be expected to increase reliance on nonrenewable groundwater, water reuse, and desalinated water. Their study also highlights an important role for development and deployment of water conservation technologies and practices.


Department of Energy scientists at Pacific Northwest National Laboratory, in collaboration with a multi-institutional team, used the Global Change Assessment Model to evaluate future water demands representing six socioeconomic scenarios. The modeling framework explicitly tracks future water demands for the agricultural, energy (electricity generation and primary energy production and processing), industrial (manufacturing and mining), and municipal sectors. The energy, industrial, and municipal sectors are represented in 14 geopolitical regions, with the agricultural sector further disaggregated into as many as 18 agro-ecological zones within each region. The scenarios showed increases in annual global water withdrawals from 3710 km3 in 2005, to 6195–8690 km3 in 2050, and 4869–12,693 km3 in 2095. Comparing the projected total regional water withdrawals to the historical supply of renewable freshwater, the Middle East exhibits the highest levels of water scarcity throughout the century, followed by India—with scarcity increasing over time in both regions. In contrast, water scarcity improves in some regions with large base-year electric sector withdrawals, such as the United States and Canada, due to capital stock turnover and the almost complete phase-out of once-through flow cooling systems.


Mohamad Hejazi
Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, MD


Research support provided by the Integrated Assessment Research program of the Office of Biological and Environmental Research within the U.S. Department of Energy’s Office of Science under contract no. DE-AC05-76RL01830.


Hejazi, M. I., et al. “Long-term global water projections using six socioeconomic scenarios in an integrated assessment modeling framework,” Technol. Forecast. Soc. 81, 205–226 (2014). [DOI: 10.1016/j.techfore.2013.05.006].

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