Integrating climate change mitigation into river basin management planning for the Water Framework Directive – A Danish case

•A map-based tool is developed to integrate climate change mitigation into WFD action programmes.•Synergies between nitrogen and GHG emission reductions for agriculture are assessed.•Agri-environmental measures can reduce both nutrient losses and GHG emissions cost-effectively.•We find a very significant potential for synergistic WFD action programmes for the case study catchment.•A differentiated approach tailored to the river basin is key to successful integration of climate change mitigation.