A Fermatean Fuzzy Merec & Waspas Methodology for Assessing the Sustainable Environmental Transformation Performance of European Union Countries

Improvement of the environment can be achieved by taking limited resources under control by giving importance to sustainable development. Especially since the policies of the European Union countries on sustainable development shape the global economy, it is important to measure the sustainable development performance of the EU countries. This study aims to propose an effective methodology for assessing the sustainable environmental transformation performance of EU countries. The outline of the proposed hybrid algorithm is based on Fermatean fuzzy sets with weighted aggregated sum product assessment (WASPAS) and MEREC. The Fermatean MEREC approach objectively determines criterion weights, while Fermatean WASPAS generates robust country rankings. Our analysis identifies "Energy productivity" as the most significant criterion among the evaluated sustainability indicators. The application of the FFS-MEREC-WASPAS framework reveals Sweden and Denmark as the top performers in environmental sustainability, demonstrating the method's effectiveness in cross-national sustainability assessment.