Sustainable use and supply of natural resources dedicated to feeding urban life are becoming increasingly complex in a time of rapid urbanization and climate change. Sustainable governance of Water–Energy–Food (WEF) requires innovative and cross-sectorial systems of provisioning. However, practitioners have often treated WEF as separate domains, while ignoring their interconnectedness. What is missing is an ‘Urban Nexus’ perspective, which assumes that environmental flows of WEF interact and relate to one another in achieving urban sustainable development. This paper contributes to theorizing the urban nexus and to understand its emergence and governance from a more socio-material perspective. It offers a conceptual framework that helps to shed light on the social and material flows shaping connections between the sectors of WEF, and the actors facilitating these connections. The paper suggests that switchers and programmers link and configure the socio-material flows of WEF facilitating the emergence of nexus governance networks and nexus programs. In doing so, the paper provides three examples of cities to test the conceptual framework by analyzing their main challenges and examples around the nexus. It demonstrates that material and social dimensions of WEF might not play an equal role in steering synergies or trade-offs—either material or social flows and their agents can be central in facilitating a nexus or in preventing it to take shape. The paper argues that material-focused methodologies need to be complemented with a social flows analysis that pays attention to the daily practice, policies, ideologies, networks or any kind of socio-cultural meaning shaping WEF provisioning.

Christian Stein, Claudia Pahl-Wostl, Jennie Barron, 'Towards a relational understanding of the water-energy-food nexus: an analysis of embeddedness and governance in the Upper Blue Nile region of Ethiopia', Environmental Science & Policy, vol. 90, pp.173-182, Elsevier BV, 2018 | Given the need for transformative changes towards more sustainable, integrated management of water, energy and food systems, the water-energy-food nexus concept seems highly relevant. However, while intuitively compelling, the nexus has also been criticized for abstracting and thereby dis-embedding the collaboration processes through which further integration could be achieved. There is a lack of empirical analysis and contextsensitive understanding, of the opportunities and constraints of, collaboration and cross-sector coordination, as faced by actors governing interconnected water, energy and food systems. In this paper we analyse how actors involved in the governance of water, energy and food systems are embedded in social networks, and discuss how that embeddedness shapes collaboration and coordination processes that are relevant for addressing interconnected sustainability challenges. Drawing on the notion of problemsheds, we delineate an analytical space that captures the interactions between water, energy and food systems and the actors influencing them in the Upper Blue Nile of Ethiopia. Our empirical data suggest that the claim that actors from different sectors are disconnected from each other is overly simplistic. The ways in which actors are embedded in hierarchical structures may help to explain why coordination challenges persist, despite the presence of cross-sectoral linkages among them