Assessing Water Scarcity Adaptation: Insights from Collective Investments and Global Policy Spillovers.

The management of surface and groundwater is a crucial component in ensuring the resilience of agricultural production, both globally and in the Western U.S., especially as the effects of climate change continue to intensify widespread and unprecedented droughts. Most of the water in the Western US is managed and distributed by irrigation organizations (IOs). In 2018, these entities served 55.5% of the total irrigated acres in the West. Although previous studies have focused on farm-level adaptations, very little is known about the investment decisions made by IOs in the adoption of adaptation strategies; this literature gap represents an urgent and understudied element in drought adaptation, especially as delays in off-farm action may compound long-term vulnerability to drought. This study empirically evaluates IO long-run adaptations to water scarcity in the Western region, exploring differences in adaptation investments based on past experiences of water scarcity and organizational characteristics. We find evidence indicating that while water scarcity experience is a driver of some adaptations, other characteristics display a higher association with adaptation likelihood. We uncover a non- linear relationship between organization size and adaptation likelihood, and a positive relationship between eligibility for federal support programs and adaptation investments.

Groundwater depletion also presents a growing threat to agricultural systems worldwide. This study focuses on California, as the state’s most valuable crops, tree nuts, both rely on and contribute to rapid groundwater depletion. The 2014 Sustainable Groundwater Management Act (SGMA) mandates sweeping reductions in groundwater use by 2040. Under the assumption that reductions in irrigated acreage will translate to decreased exports, we present a descriptive exercise assessing potential spillover effects of SGMA on global water use through virtual water exports. By estimating changing virtual water flows, this analysis broadens the discussion of Western U.S. water scarcity adaptations to consider potential global spillovers.