Monetary Valuation of Ecosystem Services from Nature-Based Solutions: Benefit Transfer of Unit Values to Polish Conditions

Nature-based solutions (NBS) are increasingly used to support climate adaptation and urban resilience; however, their environmental and social benefits are often omitted from cost–benefit analyses because standardized monetary values for incorporating these externalities into economic appraisal remain limited across many EU countries, including Poland. This study aimed to develop reference unit values for selected ecosystem services generated by NBS and adapt them to Polish conditions using benefit transfer. A literature review and a screening of institutional databases and reports were conducted, including FEMA, IGNITION and Scopus sources. The final database comprised 75 literature sources and 233 monetary estimates covering eight NBS types and a range of ecosystem services. Source values were standardized to a common area unit, updated to 2025 price levels and adjusted to Polish economic conditions using purchasing power parity and income-related corrections. The evidence base was uneven, with forests, wetlands and parks being the best represented categories and substantially fewer estimates available for technical NBS. Considerable variation was observed within individual ecosystem-service categories. The resulting values can support preliminary and comparative economic analyses in Poland, but should be treated as reference estimates rather than universal ecosystem-service prices.