Economic Sustainability of Irrigation‐Dependent Ecosystem Services Under Growing Water Scarcity. Insights From the Reno River in Italy

As water scarcity grows, irrigators are adopting modern irrigation systems to increase the proportion of water use consumed by crops and mitigate impacts on production. This increased beneficial consumption is fundamentally sourced by lower return flows‐runoff and percolation‐back into the environment, which are critical to sustain wetlands and other irrigation‐dependent green infrastructures that supply valuable ecosystem services. We adopt an innovative multi‐model ensemble of mathematical programming models to assess irrigators' responses to pecuniary compensations designed to sustain irrigation‐dependent ecosystem services (Payments for Watershed Services‐PWS), under multiple scenarios. The upshot is a database of forecasts that represents the range of plausible future states, which is used to assess economic performance and identify a robust adaptation strategy to growing scarcity. Our analysis of the Reno River Land Reclamation and Irrigation Board in NE Italy shows that, under most models and scenarios, the conservationist strategy has a superior economic performance than the autonomous adaptation strategy where modern irrigation systems are adopted. The conservationist strategy is also found more robust than the autonomous strategy. However, unless sensible incentives are put in place, irrigators may adopt irrigation technologies nonetheless. Under mild to moderate climate change scenarios, removing existing subsidies to modern irrigation systems is sufficient to deter their adoption. Under severe climate change scenarios, additional PWS to irrigators will be necessary to ensure the sustainability of irrigation‐dependent ecosystem services. Key Points We assess economic performance of conservationist (sustain irrigation‐dependent ecosystems) v. irrigation modernization strategy in NE Italy Under most models and scenarios, the conservationist strategy has a superior economic performance; and is also found more robust Unless sensible incentives are set (remove infrastructure subsidies, deploy PWS), irrigators may modernize nonetheless