Holistic and replicable quantitative assessment of non-tangible benefits of Nature-Based Solutions

In order to contrast the negative impacts of climate change, the concept of Nature-Based Solutions (NBS) has emerged as one of the favored available options. NBS are defined as “the use of natural or modified ecosystems to address societal challenges while at the same time providing a range of long-term benefits to human well-being and biodiversity”. NBS’s central concept of providing many different benefits makes them very interesting tools for adaptation, which lead them to be recommended in international environmental policy agendas, disaster risk and research programs. However, despite their potential, their implementation is lagging behind. This may be due to various reasons, but uncertainties regarding the economic feasibility of NBS are deemed to be a substantial barrier to their uptake. Therefore, the monetary quantification of NBS benefits that are not directly connected to a market (e.g., increased recreation and enhanced biodiversity – also called non-tangible benefits) is seen as a possible strategy to get closer to a complete assessment of NBS and support their prioritization. However, the complexity of setting a monetary value to non-tangible benefits often leads this kind of assessment to be left out, causing NBS to be perceived not only as less economically feasible, but also as less multi-functional.

This PhD research is part of the EU Horizon 2020 project RECONECT, and it focuses on developing and applying a new method for assessing the non-tangible benefits of NBS. The main aim is to ease the economic assessment of these solutions to support their implementation. This was achieved through a series of processes, starting with a literature review of the state-of-the-art of non-tangible benefits assessment, proceeding with the creation and application of a new methodology, and concluding with the analyses of its outcomes.

In the review of the current literature on NBS, it was found that the valuation of non-tangible benefits is not that widespread, and that the connection between the different benefits of NBS is mostly overlooked. Moreover, most of the examined studies assessed just one site at a time, thus producing very site-specific evaluations, which in turn hinder benefit transfer and upscaling of these strategies.

In order to make a step towards closing these gaps, we developed a survey directly eliciting a monetary value, in the form of willingness-to-pay (WTP), from the general public living close to and/or using an NBS site. The novelty of this method resides in the holistic approach to the information collected (i.e. spacing from socio-demographic characteristics to personal preferences on the various benefits of NBS) and in its modularity, allowing it to be tailored to different NBS while at the same time collecting the same data.

We co-designed and distributed the survey in 6 different NBS projects (both completed and under construction): two in Denmark, one in Germany, one in Italy, one in Austria, and one in the Netherlands.

The outcome of such a distribution campaign was a unique dataset, allowing for the full comparison of factors that influence the value of NBS across different European case studies. In our analyses, it was found that income, personal preferences (specifically regarding nature, e.g., the importance attributed to the increase in biodiversity), and uses of the area were the biggest influences over the value attributed to NBS across sites. Based on these results, we developed joint models to summarize and ease the upscaling of our findings.

Our survey can be further replicated and used to collect the same data in other sites, which then will be directly comparable to the information gathered in this study. Ideally, the survey could be applied in very different settings (i.e., also outside of Europe), to compare results across much diverse contexts. Thus, it could contribute to the creation of a more holistic knowledge base for secondary data analyses (e.g. meta-analyses) to develop on.

Overall, the outcomes of this project are believed to be useful, complementarily to market benefit assessments, to maximize the potential and support the implementation of NBS.