Sovereign Economic Case Builder for Nature-Based Solutions: Conceptual Framework and EU Taxonomy Alignment Methodology

This working paper presents the conceptual framework for the Sovereign Economic Case Builder (SECB), a software module designed to generate structured, evidence-based economic cases for Nature-Based Solutions (NbS) investments by integrating ecological monitoring data, cost-benefit analysis, and EU Taxonomy alignment screening within a single on-premise platform. The SECB addresses three interconnected barriers to NbS financing: the lack of standardised cost-benefit methodologies calibrated to NbS-specific co-benefits and trade-offs; the complexity of EU Taxonomy technical screening criteria (Regulation 2020/852) for climate change adaptation and biodiversity protection as applied to nature-based interventions; and the absence of tools that translate ecological performance data into the financial metrics required by green bond frameworks, blended finance vehicles, and payment for ecosystem services contracts. The paper defines a four-module architecture (NbS Cost Database, Co-Benefit Quantification Engine, EU Taxonomy Screening Engine, Investment Case Generator), proposes a stepwise EU Taxonomy alignment screening methodology for seven NbS typologies mapped to NACE economic activities, and introduces a multi-criteria cost-benefit framework that quantifies ecological, social, and financial co-benefits using both monetised and non-monetised indicators. Implications for digital sovereignty in financial data processing are discussed. The framework is designed for integration within on-premise AI infrastructure for environmental data processing.