Urban Nexus Science for Future Cities: Focus on the Energy-Water-Food-X Nexus

Purpose of Review: Rapid urban expansion of the world’s cities is placing unprecedented demands on the energy, water, food, and other (X) systems (e.g., mobility) that each offer multiple life-supporting services. Coordination that considers inter-sectoral connections among these urban systems and services remains nascent in practice, yet are critical to the future well-being, resource/operational efficiency, and resilience of urban areas. This paper therefore proposes an applied “urban nexus science” framework to identify integrated and synergistic pathways toward achieving urban sustainability. Recent Findings: The design, planning, and operation of urban W-E-F systems can benefit from integrated analyses to accelerate infrastructure, land use, and hazard mitigation planning and decision-making. New knowledge quantifying the key effects of W-E-F systems designed in isolation versus an increasingly integrated systems, especially when exposed to hazards, health risks, or extreme events, are a critical need. Summary: Interactive system modeling and participatory technologies are needed to support stakeholder engagement and two-way (and multi-directional) information flow, for exploring outcomes of alternative solutions for integrating W-E-F sectors. To support such important efforts, research is needed to fill critical gaps in data, identify tradeoffs, and develop synergistic solutions that measure sustainability co-benefits based on different levels of urban integration among W-E-F systems and services.