The Water, Energy, Food Nexus (WFE) has become popular in recent sustainability research. Since the conferences World Economic Forum 2011 in Bonn, the World Water Forum, the Rio+ 20 Conference 2012 as well as the Stockholm Water Week 2014, the goal to achieve water, energy and food security is widely agreed upon. Unfortunately, the related resources exhibit trade-offs, thus advancing in one area may limit the security of another. Understanding the interactions between the three fundamental sectors and quantifying them can help to identify the most relevant interlinkages. Developing different scenarios and using them to inform decision making and policy development will be the main goal of implementing WEF Nexus related research. It is indispensable to develop adequate methods and models to perform quantitative assessments of WFE and apply them to river basin to support decision making.
Many scholars have recognized the Nexus as an innovative and promising approach (Allan et al., 2015; Struik et al., 2014; Ringler et al., 2013) to inform governments, It shifts attention from the one-sector view to a more balanced view of issues linking the three resources. However, there is a lack of quantitative methods to assess Nexus trade offs and conflicts. Only quantitatively, its status and its sensitivity to global change drivers can be really understood. Many Nexus approaches have been developed and some of them work at different scales with different requirements, e.g. hydro-economic modelling or integrated WEAP-LEAP analysis (Jägerskog et al., 2013). Other methods focus on integrated modelling based on system thinkings (Bazilian et al., 2011). Different methods of life cycle analysis (LCA) and efforts to integrate different available decision support system for the energy sector (PODIUM) are highlighted. Global change factors such as climate change are considered as important and are introduced by other authors as Nexus-smart policies and adaptation measures (Golam and Sharma, 2015).
Economic and social context
Natural resources form a pivotal base for economic development, social wellbeing and environmental integrity. Among them, water, energy and food (land) play a fundamental role as they are closely linked to most of the objectives of sustainable development. Water is particularly impacted by climate variability and climate change and increasing competition from different sectors (IPCC, 2014). In many countries the economic growth is coupled to the energy use and demand and the challenges superimposed by climate change mitigation imply that the country must focus on the development of clean and renewable sources of energy. Finally, the provision of food to meet the demand is an objective that is always affected by global change drivers (Wheeler and von Braun, 2013).
The theoretical concept
The WFE Nexus offers a theoretical concept to face rising global challenges about water, energy and food security (Meza et al., 2015). At the same time the Nexus recognizes the interdependencies between the three resources. The core of the WFE Nexus takes into account interactions between the environment, society and economy (e.g. Bizikova, 2013; Hoff, 2011). WFE Nexus is a concept that explicitly represents challenges and interrelationships between involved resources, and allows the exploration of strategies for a holistic management of intertwined resources, improving their efficiency (Meza et al., 2015). There is a need to carry out case studies to evaluate the status of the WFE Nexus at basin level and to assess the availability of its components in comparison to demand patterns (Waughray, 2011), and to tackle identified challenges. By identifying the components, each step has to be unpacked and the dynamics have to be analyzed from regional to global scale. This allows presenting a convenient framework to analyze and take action to improve water security (Beck and Villarroel Walker, 2013), defined as an availability of an acceptable quantity and quality of water, as well as an acceptable level of water-related risks to people, environments and economics (Cook and Bakker, 2012).
A Venn diagram showing the intersections of individual sets (energy security, water security and food security) is commonly used to present the concept. This approach does not allow the incorporation of dynamic driving forces such as global environmental change. Tradeoffs and synergies cannot be determined as well. The approach shows influences, supplies or demands which are indicated by arrows. Within this framework, the dynamic nature of the nexus is represented as changes in the size of the units, their composition and by changes influenced by other systems (Meza et al., 2015). Since the driving forces of the global change are connected directly or indirectly to each of the component of the nexus, the nature of the nexus turns into a more complex structure and therefore becomes a more vulnerable system.
The arrows in this figure represent supply flows provided - or demands exerted - by each subsystem and thus imbalances between both generate problems of water, food and energy security. Each system has been divided to specify its potential effect that global change will have on the nexus. Energy is divided into renewable (i.e. hydropower, wind, solar, biofuels, etc.) and non-renewable sources (those that are directly associated to greenhouse gas emissions from fossil fuels). The food system is able to deliver traditional goods and services as well as biofuels. Finally the water system is divided into surface water (because its relevance for hydropower generation) and groundwater (which demands energy for pumping).
Consequences of global change are able to increase the number of arrows representing interactions. The change over time can be seen as an indicator of sensitivity of each system.
The Nexus model is able to communicate complex system interaction and dependences among its elements. The changes in its components and relationships as a consequence of global change drivers are still difficult to identify and this limits its applicability to communicate future challenges to stakeholders and policy makers. It remains a task of scientists to communicate the WFE Nexus clearly and to offer options how to manage it.
References and further reading:
Allan, T., Keulertz, M., Woertz, E. (2015). The water-food–energy nexus: an introduction to nexus concepts and some conceptual and operational problems, International Journal of Water Resources Development, 31(3).
Bazilian, M. et al. (2011). Considering the energy, water and food nexus: Towards an integrated modelling approach, Energy Policy, 39(12), 7896-7906.
Bizikova, L. et al. (2013). The Water–Energy–Food Security Nexus: Towards a Practical Planning and Decision-Support Framework for Landscape Investment and Risk Management, Winnipeg, Canada: International Institute for Sustainable Development (IISD).
Beck, M.B., Villarroel Walker, R. (2013). On water security, sustainability, and the water-food-energy-climate nexus, Front. Environ. Sci. Eng, 7, 626–639, doi:10.1007/s11783-013-0548-6.
Cook, C., Bakker K. (2012). Water security: debating an emerging paradigm, Global Environmental Change 22(1), 94–102.
Golam, R., Sharma, B. (2015). The nexus approach to water–energy–food security: an option for adaptation to climate change, Climate Policy.
Hoff, H. (2011). Understanding the Nexus. Background Paper for the Bonn2011 Conference: The Water, Energy and Food Security Nexus. Stockholm, Sweden: Stockholm Environment Institute (SEI).
IPCC (2014). Climate Change 2014: Impacts, Adaptation, and Vulnerability, Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1132 pp.
Jägerskog, A., Clausen, T. J., Lexén, K., Holmgren, T. (eds.) (2013). Cooperation for a Water Wise World – Partnerships for Sustainable Development, Report Nr. 32, Stockholm International Water Institute, Stockholm, 45-50.
Meza, F. J., Vicuna, S., Gironás, J., Poblete, D., Suárez, F., Oertel, M. (2015). Water-food-energy nexus in Chile: Illustrating current WFE status and communicating future challenges due to global change in different regional contexts. Water International, (ahead-of-print), 1-17.
Ringler, C., Bhaduri, A., Lawford, R. (2013). The nexus across water, energy, land and food (WELF): potential for improved resource use efficiency?, Current Opinion in Environmental Sustainability 5.6, 617-624.
Struik, L.C., Jong, S.V., Shoubridge, J., Pearce, L.D., Dercole, F. (2015). Risk-based Land-use Guide, Geological Survey of Canada.
Waughray, D. (ed) (2011). Water security: the water-food-energy-climate nexus, World Economic Forum, Island Press, Washington, DC.
Wheeler T, von Braun J. (2013). Climate change impacts on global food security, Science 341(6145), 508–513.