National climate scenarios for Belgium

Developing national climate scenarios allows for a consistent translation of global and regional climate projections into information relevant for impact modelling and decision-making within Belgium. We present a new set of national climate scenarios developed within the CORDEX.be II project, based on kilometer-scale regional climate model (RCM) simulations. The ensemble includes three RCMs (ALARO, MAR, and COSMO-CLM) that simulate the present-day climate and two 20-year future periods representing global warming levels of +2°C and +3°C. The downscaling specifically targets the representation of climate extremes, including heatwaves and heavy precipitation events. Boundary conditions are derived from global climate models from the 6th phase of the Coupled Model Intercomparison Project (CMIP6), that perform well in reproducing these extremes. The performance of the three models is evaluated through an analysis of their ability to simulate key climate variables for the present-day period. The resulting scenarios provide a robust basis for assessing climate impacts across multiple sectors, including agriculture, health, and water management, and for supporting adaptation planning to future climate extremes in Belgium.