Forecasting environmental protection expenditure: A transdisciplinary framework for sustainable development validated...

This study presents a transdisciplinary framework for forecasting environmental protection expenditure (EPE), validated within the Turkish macro-institutional context. The research integrates econometric forecasting with environmental policy and resource management to project national and domain-specific EPE, bridging the gap between abstract econometric modeling and actionable institutional policy recommendations. Novel GDP-based and trend continuation models were developed to address the global challenge of financing environmental protection and achieving the United Nations Sustainable Development Goals (SDGs). The robust GDP-based models, which align closely with historical data, project Türkiye's total EPE to reach 11.2 to 20.8 billion US$ by 2029. This significantly contrasts with trend continuation forecasts of 5.5 to 11.1 billion US$, highlighting an imminent green funding gap and the critical role of economic growth in funding sustainable transitions. Considering Türkiye's 2023 expenditure of 9.4 billion US$, these projections offer practical implications for strategic planning, fiscal tools like green bonds, and resource allocation. Domain-specific forecasts, such as those for waste and wastewater management, underscore areas vital for local environmental quality. This scalable methodology provides a crucial tool for institutional policymakers, informing evidence-based decisions and accelerating environmental innovations to achieve national and global sustainability goals.