Nature-based solutions (NBS) play an important and increasing role in both adaptation and disaster risk management. This is also recognized within several global and European agreements and policies (e.g., UN’s SFDRR, EU Green Deal, the EU Adaptation Strategy) which embed NBS as a means to address climate change adaptation (CCA) and disaster risk reduction (DRR) as well as other societal challenges (e.g., biodiversity loss, climate mitigation). This calls for fit-for-purpose assessments, which critically assess the suitability of NBS for addressing climate change and other hazard impacts and monitor the success of their implementation, to inform (future) policies and actions, as well as evaluate implemented policies.

The technical report provides a concise overview of available NBS assessment approaches in the context of adaptation to climate change and disaster risk reduction, based on information from literature and selected European cases. The first theoretical part looks at the reasoning behind and purpose of carrying out NBS assessments and the available methodological approaches matching decision-makers' needs. Here, we present a step-wise framework for designing user-oriented NBS assessments, building on key success factors and limitations identified in the literature. The second part looks at real-world lessons learned from successes and challenges in working with NBS assessments and illustrate a range of different NBS assessment approaches applied in Europe for a wide range of NBS assessment purposes and uses. The report concludes with a reflection on key elements for designing and implementing NBS assessments drawn from the insights gained in this study.