An Integrated Assessment Model for the German Food-Energy-Water Nexus
The United Nations has defined the food-energy-water nexus as a key issue in the green economy process towards sustainable development. The integrated assessment model is used here to frame and study the heterogeneity of the food-energy-water nexus and to manage the food-energy-water nexus in Germany in a social learning and decision-making process. For the integrated assessment of the German food-energy-water nexus sector, a four-phase approach based on the de Ridder method is used to analyse the food-energy-water nexus against the background of the completely revised German sustainability strategy of 2017. In the first step, the integrated assessment problem analysis, the interconnections of the food-energy-water nexus between the natural resources and the socio-economic system are formulated. The new political values and options needed for the management of the food-energy-water nexus sector are revealed in the second research step and it is stressed that justice is the defining ethical norm of the revised German sustainability strategy of 2017, which is the sustainability framework for the German food-energy-water nexus. Thus, inter- and intragenerational justice is also a central issue of the food-energy-water nexus and is integrated with the social discount rate in the food-energy-water measuring concept (Fisher nexus quantity index) presented in the third step. In the final research step of the integrated assessment approach, it is found that the new food-energy-water nexus policy process also needs a ‘culture of reflected numbers’, as Voßkuhle calls it, to ensure a social discourse as a permanent learning process for both the German government and society.