Author(s): Amin Elshorbagy; Lina Wu
Linked Author(s): Amin Elshorbagy
Keywords: Water-energy-food nexus; Assessment framework; Climate change; Irrigation expansion; Saskatchewan
Abstract: Basic human needs in the forms of water, energy, and food (WEF) are challenged across the globe by various limitations, with water being the most obvious one. The interactions and feedback loops among WEF systems, creating what is called WEF nexus, lead to trade-offs but also potential synergies under different natural conditions, policies, and management decisions. We developed a WEF nexus model that incorporates both supply and demands sides of WEF systems into a single system-of-systems model using the system dynamics approach. The model is applied to the province of Saskatchewan, Canada, and so is named WEF-Sask model. WEF-Sask includes the water resource system, rainfed and irrigated agricultural crop production, and the various sources of energy production (hydro, thermal, wind, and bioenergy) and their uses for residential, industrial, and agricultural activities. The results reveal the various levels of sensitivities of water, energy, and food sectors to the socioeconomic and climatic drivers. The analysis of trade-offs and synergies shows that the proposed large irrigation expansion in Saskatchewan boosts the provincial food production by 1.6% while reducing hydropower production by 2.7%. Wind expansion strategy makes synergies that not only contribute to electricity supply but also reduce greenhouse gas emissions, industrial water demand, and groundwater use by 2.0, 5.7, and 3.8%, respectively. Biofuel use in transportation cuts GHG emissions by 1.2% but reduces the potential food export by 5.0%. The WEF-Sask model allows for scenario analysis toward integrated resources management, which provides multi-centric assessment of water resource policies and management plans. Furthermore, the WEF nexus has been investigated under ensemble of climate change, transboundary inflows, and policy options. The time horizon includes a baseline (1986-2014) and the near-future climate scenarios (2021-2050). Results show that the WEF nexus in Saskatchewan is vulnerable, with 22% of 7500 simulations cannot meet pre-set food and hydropower production targets. Decreasing transboundary inflows and local dry weather are the greatest threat to the WEF nexus performance, suggesting the critical role of hydroclimatic conditions and water policy in the upstream province of Alberta. Renewable energy expansion leads to the best nexus performance during 2021-2050, reducing total water demand, groundwater demand, and greenhouse gas (GHG) emissions by 2.6%, 8.2%, and 10.5%, respectively. Irrigation expansion plans are projected to improve the resilience of food production to climate change by turning two future scenarios (SSP126 and SSP245) from undesired scenarios to desired ones and increases food production by 3.6%. However, this policy also significantly increases total water demand (62.2%), resulting in reduced hydropower production by 3.2% and water transferred to the downstream province of Manitoba by 3.3%. This study provides a comprehensive modeling-based framework to assess water-energy-food nexus.