The Urban Water–Energy Nexus: Building Resilience for Global Change in the “Urban Century”
The urban water–energy nexus is defined as the interlinkages among water, energy, and attendant infrastructure, coupled with the populations that rely on them and the institutions for their governance. Because these interlinkages shape the future trajectory of cities – their form, function, and footprint – the nexus can be harnessed as a holistic policy tool to incorporate a holistic approach to build societal and ecosystem resilience to global change. Resource attributes of water and energy along with the large infrastructure systems conventionally used to source, transport, and distribute them, plus recover waste, make water and energy the core resources to consider for urban planning in a nexus framework. Urbanization drives the nexus in unique ways due to (a) political/economic power and demographic concentration in cities, (b) reliance on infrastructure, (c) global change forces, and (d) unique urban social vulnerabilities. In the face of multiple global change uncertainties, cities are experiencing increasing pressures as a result of climate change and economic globalization. Resilience provides a guiding principle for multi-scalar urban planning and management to increase urban adaptive capacity. Research gaps and next steps in urban water–energy nexus research and practice are centered on more robust analysis of waste and resource recovery, including the opportunities and limits to efficiency gains.