Abstract

The water-energy-food-ecosystem nexus Nexus (WEFE nexus) is the approach that postulates that water security, food production, natural ecosystems and energy production must be researched, managed and planned together. The interaction between those sectors are numerous and their dependencies can lead to synergies, that is beneficial join opportunities, or trade-offs, understood as an improvement in one sector which causes damage in another sector. On top of the complexity of the WEFE nexus, large trends, such as climate change, technological advancements and demographic change have strong effects in the WEFE nexus.

Our group at the Ludwig-Maximilians-University in Munich has researched the status, characteristics and dynamics of the nexus systems through simulation of scenarios in different modelling systems. Climate models (GCMs), hydrology models (GHMs), energy models (IAMs) and ecological, vegetation and land use models (DGVMs, crop models, etc.) and economic models (general and partial equilibrium models) have been used for this purpose.

Recently, Prof. Dr. Fader had the idea of researching the WEFE nexus using tools from complex system science. Why? Because the WEFE nexus is a complex system composed by complex subsystems. A complex system is not a complicated system, it is a system that has characteristics at the system level that do not appear when the system is deconstructed in its parts. That means that the system is much more than the sum of its parts. This is called “emergence”. Such characteristics are for example self- evolution and adaptation, pattern formation, nonlinear dynamics, hysteresis. Some of the tools from complex system theory that may be relevant for this context are network theory, chaos theory, non- linear system dynamics, complex adaptive system analysis. But also “simple” systems of differential equations may be used to describe some dynamics. The chair of Prof. Fader is searching for collaborations that help us to use complex system methodologies for the analysis of the dynamics of the WEFE nexus.

The presentation will introduce the nexus concept, give an overview of the model we use, present some examples about past research and some ideas about future work.