Water shortage due to urban climate imbalance in water, food, and energy nexus and the role of their respective resource recovery

Urban areas, in particular, are more susceptible to flooding due to the substantial presence of impermeable surfaces, such as asphalt and concrete roadways, which exacerbate runoff and reduce natural water absorption. This issue, coupled with water scarcity intensified by anthropogenic activities and climate disruptions, highlights the interconnected challenges addressed by the water-energy-food (WEF) nexus framework. While water shortages are a global concern, their impacts are disproportionately severe in specific regions, such as arid and semi-arid zones, rapidly urbanizing cities, and regions heavily reliant on agriculture. These areas are particularly vulnerable to the compounded effects of climate variability, over-extraction of water resources, and unsustainable land use practices. This chapter focuses on these vulnerable regions, thus exploring how resource recovery practices integrated within the WEF nexus can mitigate localized water stress. Key strategies include reusing treated wastewater for agricultural irrigation, thus generating biogas from organic waste and optimizing green water through urban farming systems. These circular economy-based solutions not only alleviate water scarcity but also reduce dependency on finite resources, create economic opportunities, and promote environmental sustainability. Case studies from diverse geographic and socioeconomic contexts demonstrate the scalability of these practices and their alignment with global sustainability goals, including SDG 6 (Clean Water and Sanitation) and SDG 13 (Climate Action). In addition, this chapter examines the critical roles of governance, technology, and tailored policy interventions in enabling effective implementation. By emphasizing region-specific challenges and solutions, this chapter underscores the need for localized yet scalable resource recovery strategies to foster resilience against water scarcity and support sustainable development in the most affected areas.