CBAM Cost Exposure and Farm Input Price Risk in the Fertiliser Value Chain: A Two-Level Soft-Set and Multi-Criteria Analysis for Türkiye

The European Union (EU) Carbon Border Adjustment Mechanism (CBAM) prices the embedded emissions of imported fertilisers, while nitrogen fertilisers are among the most volatile farm inputs in supplier countries. This study analyses both exposures for Türkiye in two complementary rankings. Stage 1 ranks 21 non-EU suppliers of six CBAM-covered fertilisers from an EU importer’s sourcing perspective; Stage 2 ranks 16 Turkish input groups on descriptive price-risk indicators for January 2020–July 2026 and on base-year index weights. Rankings use the Relational Membership Value Calculation (RMVC), its weighted extension, the Maji–Roy choice value, three compensatory multi-criteria methods and a consensus ranking. Under a 79 €/tCO2e reference price, Türkiye’s modelled 2030 charge equals 32.6% of export value (supplier mean 22.9%), with ammonia, urea and calcium ammonium nitrate carrying 93.9% of it; on the carbon criteria alone Türkiye ranks 18th of 21. Its overall rank (1st to 17th) is driven by market attributes and falls to 9th to 18th when carbon criteria receive half of the weight. Nitrogen fertilisers rank first or second under all twelve full-sample combinations, but their lead weakens after 2023 and under block-bootstrap resampling. RMVC resolves ties, yet with ties handled at fixed cardinality it identifies top alternatives no better than Maji–Roy.