The study analyzed 45 toolkits to identify best practices in cost-benefit analysis for Nature-based Solutions (NbS). We considered a resource to be a toolkit if it contained guidance on specific steps, tools or a process for either selecting NbS or assessing them. The approach to cost-benefit analysis, inclusion of benefits and costs, and incorporation of climate considerations was analyzed. The authors identified numerous toolkits with valuable guidance that may be relevant for UNDP-supported projects, and include case studies of seven of these toolkits in the appendix. However, no single toolkit yet comprehensively provides guidance for cost-benefit analysis of NbS with a climate lens.
Based on this analysis, the authros conclude with a series of recommendations for a toolkit to support cost-benefit analysis of NbS with a climate lens. Critically, guidance should be directly contextualized to the LAC region with particular attention to the economic, ecosystem, and policy environment and feedback from project stakeholders. Attention to the long-term nature of NbS investments and the implications for cost-benefit analysis is also important (a key challenge for NbS is that the benefits can take several years to be fully realized compared to gray infrastructure solutions, requiring a long-term perspective). Incorporation of climate projections and guidance on the use of climate models is critical to ensure that NbS investments are climate-resilient. This report and recommended guidance are intended to support NbS practitioners looking to identify the full range of social, economic, and environmental benefits and costs resulting from NbS. A credible, evidence-based foundation for assessing the benefits and costs of NbS can help to identify the most effective allocation of limited resources to address the drivers and consequences of climate change.