Lesson learnt from the OPERANDUM project: A novel framework for hydro-meteorological risk reduction using nature-based solutions.

Hydro-meteorological risks (HMR) such as river flooding, coastal erosion, salt intrusion are becoming more and more damaging due to climate change. The impact of HMR is expected to lead to relevant economic losses and additional $CO_2$ emissions affecting resilience and exacerbating in turn climate change. In this communication we will discuss the lesson learnt from the project H2020 OPERANDUM to demonstrate the ability of nature-based solutions (NBS) to reduce hydro-meteorological risks. In this context a novel framework for the assessment of risks resulting from heat waves with the aim of quantifying the main contributions to economic losses and $CO_2$ emissions is presented. The formulation of the framework includes the the description of the NBS, used to enhance our adaptive capacity in a sustainable and cost-effective way. Since NBS consist of natural features that are also exposed to heat waves, the entire life cycle of NBS is considered ($i.e.$, the implementation, maintenance, and possible restorations). The proposed framework stands as a tool for assessing the local impacts of already implemented or designed NBS in the current and future climate scenarios.