Beyond meta-studies: Learnings from a large multi-site primary dataset on non-tangible benefits of nature-based solutions

Nature-Based Solutions (NBS) are growing in popularity as approaches for, among others, the reduction of hydro-meteorological risks. However, their uptake is still slow despite the recognition of their role in enabling a smarter, more systemic, and faster adaptation to climate change. Uncertainties regarding the valuation and subsequent economic feasibility of NBS are deemed to be a substantial barrier to their uptake. The monetary valuation of the non-tangible benefits of NBS (e.g., increased recreation and enhanced biodiversity) is seen as a plausible strategy to get closer to providing a holistic assessment. However, the quantification of these non-tangible benefits is often not integrated into economic assessments of NBS, partly as methods that can be replicated across sites have been lacking. This situation risks leading to inconsistent and/or biased valuations, which may negatively influence or delay the prioritization of NBS. Thus, our study aims to collect primary data on the non-tangible benefits of NBS across different European study sites and to identify patterns in how the different types and contexts of NBS influence people's valuation. We applied a contingent valuation survey to six different peri‑urban NBS study sites, where the focus is on the reduction of hydro-meteorological risks. The target of the survey was the general public, and we used willingness-to-pay questions to quantify the value given by the respondents to the NBS. Our results highlighted that people value the multiple benefits of NBS, and positively react to implementations improving nature across all sites. Moreover, similar variables seem to influence the value attributed to NBS across sites, with income and personal preferences ranking highly among them. These insights indicate that decision-makers and NBS-planners can learn more broadly from past experiences from a variety of (cultural) contexts, which can assist in delivering more targeted and multi-functional NBS.