Modeling Study of Irrigation Effects on Global Surface Water and Groundwater Resources
The hydrological cycle is influenced by climate, but also regulated extensively by human activities such as irrigation and groundwater pumping that also respond to climate. A team of scientists, led by U.S. Department of Energy researchers at Pacific Northwest National Laboratory, presented a first-of-its-kind study that looks at impacts of irrigation on both surface water and groundwater resources at the global scale under the Coupled Model Intercomparison Project Phase 5 climate scenarios. The team conducted three different sets of numerical experiments driven by bias-corrected climate projections from five general circulation models (GCMs) to analyze the effect of irrigation on global surface water (SW) and groundwater (GW) resources. They found that irrigation could lead to SW/GW depletion in many intensely irrigated regions. Irrigation depending primarily on SW tends to have larger impacts on low-flow than high-flow conditions, suggesting increased vulnerability for drought. By the end of this century, combined effects of increased irrigation water demand and amplified temporal-spatial variability of water supply may lead to severe local irrigation water scarcity. The team highlighted the need to account for the effects of irrigation and its water sources in assessing regional climate change impacts.
Leng, G., M. Huang, Q. Tang, and L. R. Leung. 2015. “A Modeling Study of Irrigation Effects on Global Surface Water and Groundwater Resources under a Changing Climate,” Journal of Advances in Modeling Earth Systems 7(3), 1285–304. DOI: 10.1002/2015MS000437.