Friday 16 Nov 2018Data Driven Quantification of the Global Water-Energy-Food System

Dr Janez Susnik - IHE Delft Institute for Water Education

Harrison 170 13:30-14:30


There is increasing interest in the global water-energy-food (WEF) system and the future direction of this system. This is particularly pertinent regarding concerns over resource exploitation, sustainability, and equitable access for a growing population. Many studies investigate different aspects of this system, however there remain a number of shortcomings in modelling efforts. Such shortcomings include only representing one or two system sectors, or focussing on very specific case studies that are not generally applicable. This work presents a global analysis of the WEF-GDP (Gross Domestic Product) system, integrating these four sectors into a single, coherent analysis and modelling approach, offering consistency where it has been previously lacking. A Monte-Carlo sampling approach is adopted to characterise global variability. A system dynamics modelling approach quantifies a previously qualitative description of the global WEF-GDP system. Correlative and causal analysis shows links of varying strength between the WEF-GDP sectors. For example, the GDP-electricity consumption sectors are very strongly correlated while food and electricity consumption are more weakly correlated. Causal analysis reveals that ‘correlation does not imply causation’, often the case in complex systems. There are noticeable asymmetries in causal relationships between sectors. Historical values of WEF and GDP are well recreated. Future scenarios were assessed using seven GDP growth scenarios to 2100. Water withdrawals are close to other values estimated using very different approaches, and results suggest that humanity is at risk of exceeding the ‘safe operating space’ for water withdrawal. Food production estimates are also close to other studies by 2050, while electricity consumption is overestimated. This work demonstrates a novel methodology and is one of the first studies to quantify the global WEF-GDP nexus and is a valuable early step in providing a quantitative modelling framework to the previously qualitative descriptions of the water-food-energy-economic system.

Keywords: Correlation and causality; nexus; system dynamics; water-energy-food


Dr. Janez Sušnik is Senior Lecturer at IHE Delft Institute for Water Education. His research focuses on quantitative modelling of the water-energy-food system at many scales. He is interested in deepening understanding on how WEF systems behave and their trajectories into the future, especially at the global scale. He also has interests in water-energy relationships in cities and in sustainable urban water supply, especially in the context of rapidly developing cities. At present, he is involved in two major research projects focussed on these themes: water-energy-food systems modelling – SIM4NEXUS ( and sustainable urban water supply (

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