The proposed research will be conducted within the Community Earth System Model version 2 (CESM2), a fully coupled, state-of-the-art earth system model whose simulations have contributed to the Intergovernmental Panel on Climate Change’s (IPCC) sixth assessment report (exp. 2021). CESM is tested and developed by an international research community of more than 5000 scientists and CESM1 is considered to be the best performing model of its generation. However, water management is poorly parameterised (e.g., no reservoir operation), routed water is decoupled from landscape processes (e.g., river water is not available for irrigation), and adaptation options in the water sector are absent (e.g. no climate-smart irrigation). In this project, we will improve CESM to include (i) a two-way coupling between landscape processes and routing; (ii) crop irrigation, industrial and domestic water use from routed freshwater and reservoirs [Secondment to IIASA]; (iii) scenarios of climate change adaptation options for irrigation [Secondment to Climate Analytics]. By explicitly considering climate change adaptation in a subset of global-scale simulations, we will be able to forecast the added value of adaptation in alleviating impacts projected under no-policy scenarios.