Perspectives, challenges and directions for future research into the water-energy-food (WEF) nexus

In 2018, Albrecht et al. published a review of water-energy-food (WEF) nexus literature, coming to five main criticisms in nexus research. The five central conclusions of that review together with a consideration of on-going projects and recent nexus research insights form the basis for this critical review. The current state of nexus research, and in particular modelling research, is examined and updated to reflect recent advances and correct misperceptions, and put them in the context of larger epistemological issues. The main conclusions are: 1) The considerable and growing diversity in nexus studies precludes a one-size-fits-all approach. Indeed, it has never been an objective to develop a ‘grand unified nexus theory or model’; 2) A lack of ‘fundamental equations’ between many nexus parameters hinders full quantification of nexus linkages, though data-driven, stochastic and agent-based approaches offer avenues for development; 3) The use of qualitative and social science methods in nexus studies is rapidly gaining traction, especially when blended with quantitative modelling outcomes; 4) Progress has been made in attempting to break disciplinary siloes, especially when considering integrated assessment models and system dynamics models.