Speaker: Megan Konar, University of Illinois at Urbana-Champaign
Abstract: The Central Valley of California is one of the most productive agricultural locations in the world, which is made possible by a complex and vast irrigation system. Beginning in 2012, California endured one of the worst droughts in its history. Local impacts of the drought have been evaluated, but it is not yet well understood how the drought reverberated through the global food system. Here, we quantify drought impacts to the water footprint (WF) of agricultural production and virtual water transfers (VWT) of the Central Valley of California. To do this, we utilize high spatial, temporal, and water source resolution datasets and a crop model from pre-drought conditions (2011) through three years of exceptional drought (2012–2014). Over the course of the drought, there was a 0.6% increase (0.128 ⨯ 109 m3) in total WF. In particular, the groundwater WF increased from 6.00 ⨯ 109 m3 in 2011 to 11.61 ⨯ 109 m3 in 2014, predominantly in the Tulare Basin. However, production and food transfer declines led total VWT to decrease by 0.7% (0.097 ⨯ 109 m3). From 2011 to 2014, groundwater VWT increased by 3.19 ⨯ 109 m3, partially offsetting the 0.71 ⨯ 109 m3 reduction in green VWT and the 2.58 ⨯ 109 m3 decrease in surface VWT. During the drought, global consumers increased their reliance on the already overexploited Central Valley Aquifer by 93.4% (5.61 ⨯ 109 m3). These results indicate that drought shocks may strengthen the telecoupling between unsustainable groundwater withdrawals and distant consumers of groundwater-intensive agricultural commodities.