Groundwater depletion embodied in transfers and exports of the United States

The United States plays a key role in global food security by producing and exporting agricultural products all over the world. Irrigation from groundwater resources is increasingly important in agricultural production in the US. Groundwater withdrawals for irrigation have nearly tripled since records began in 1950, even accounting for recent water use efficiency gains. Increased reliance on groundwater and prolonged unsustainable pumping of aquifers has led to groundwater depletion in many areas. In this study, we ask: How much groundwater depletion is embedded in the domestic and international agricultural exports of the United States? What is the mass and value of domestic and international agricultural commodity transfers that rely on unsustainable groundwater use? To address these questions we combine state-of-the-art groundwater models with statistical information on agricultural production, transfers, and exports of the United States. We find that 26.3 km3 of nonrenewable groundwater was transferred domestically in 2000, with 2.7 km3 being sent abroad. In 2010, 34.8 km3 was transferred domestically and 3.7 km3 was exported. This indicates an increase of 32% in domestic transfers and 38% in international exports. In 2000, we find that 1,491,126 Ktons (340 billion $USD) of agricultural products reliant on nonrenewable groundwater was domestically transferred, while 119,048 Ktons (47 billion $USD) was exported. In 2010, the mass transfer of agricultural goods reliant on unsustainable groundwater decreased, but the value of agricultural commodities reliant on unsustainable groundwater use in national and international supply chains increased by 54% and 31%, respectively. Our results highlight the need for scientists, policy makers, and supply chain managers to consider the risks posed to global food supply chains from reliance on unsustainable groundwater use.U of I OnlyAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD syste