Global Nexus challenges identified

Marc Bierkens (Utrecht University) and the global case study team work alongside experts to identify the key WEFE challenges for the global case study.

Climate change, population growth and economic development are increasing the demand for water, food and energy worldwide. The associated challenges in managing the Water, Energy, Food and Ecosystem (WEFE) nexus that are globally ubiquitous and form part of our global GoNexus case study.

Recently, in dialogue with global policy makers and the consortium, the GoNexus global case study team identified the most important WEFE challenges. The overarching WEFE challenge is that increased water demand by one sector, e.g. water for irrigation, will impact water availability for other sectors, e.g. domestic water or water for ecosystems.

Specific WEFE nexus challenges that GoNexus will target are:

1) the impact of a shift to renewables on water use (e.g. energy cropping) and shifts in water availability (hydropower reservoirs and dams);

2) the increase in energy demand that results from technologies to mitigate water scarcity such as desalinisation, treated waste water (re-)use and Managed Aquifer Recharge (MAR);

3) the impact of increases in water and energy use by sectors on biodiversity by reducing streamflow (by consumptive water use), changing timing of streamflow (by reservoirs and dams), increasing water temperature (by cooling of power plants) and fragmentation (by dams);

4) the search for regional and global policies that are robust under change, economically and ecologically sustainable and avoid improving one part of the nexus by overtaxing another part.

To tackle these challenges, GoNexus will set up a global WEFE modelling framework. This framework consists of global and continental scale hydrological models, an agricultural sector model, energy models, a global macroeconomic and trade model and global biodiversity model. Currently the models are being improved to address these challenges. After that, the global models will be used to project the future state of the global WEFE nexus. This is achieved by ‘forcing’ the global models with outputs from global climate models following climate and socioeconomic scenarios. From these results, we will assess the magnitude of the future global WEFE challenges under these scenarios and assess the efficacy and robustness of global policies to manage these.

Article authored by Dr. Marc Bierkens, Professor of Hydrology and Chair of Earth Surface Hydrology Group, at Department of Physical Geography, Utrecht University.