Spatio-temporal evolution of annual and seasonal water scarcity in China, India, and the United States
Date
2021
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Publisher
University of Delaware
Abstract
Growing food demand has been the primary cause of increasingly unsustainable water consumption in the world’s breadbasket regions. This unsustainable demand can have steep human and environmental consequences, leading to physical and economic hardship among vulnerable communities and depletion of environmental flows needed to support ecosystem functioning. While previous research has assessed historical trends in water scarcity (i.e., the condition under which water demand exceeds availability), these studies have focused on annual time scales or on large geographic units, limiting the ability to identify specific places, times, and crops that offer the greatest opportunity for addressing unsustainable water consumption. Here we utilize detailed county-level agricultural census in China, India, and the United States - which together comprise 41% of the world’s population and contribute 39% of global crop production - to perform a spatially and temporally-detailed quantification of historical trends in water scarcity since 1980. To do this, we first estimate monthly time series of crop-specific water demand by combining information on harvested area and crop water footprint, as well as water use data for other societal sectors. We then compare this to monthly water availability (accounting for environmental flows) to identify where, when, and by what magnitude demand exceeds availability in these countries. In doing so, the outcomes of this assessment can provide a basis from which to explore potential agricultural solutions for alleviating future water scarcity, such as improving crop water use efficiency and the optimization of cropping patterns. This improved understanding of historical trends of water scarcity also has the potential to inform decision making aimed at balancing the water resource needs of humanity and nature.
Description
Keywords
Agriculture, Food, Hydrogeology, Hydrology, Water resources, Water scarcity