One Supply Chain, Two Pressures: The Carbon Cost Hidden in Türkiye’s Fertiliser Trade

The study compares 21 non-EU suppliers across six fertiliser products using trade data from 2023–2025, then examines 16 Turkish agricultural input groups between January 2020 and July 2026.

Fertiliser bills can turn a carefully planned growing season into a financial struggle, especially when prices move faster than farmers can adjust their spending. Türkiye's fertiliser industry faces another pressure in European markets, where the emissions associated with production carry a carbon cost. Research examines these two pressures across the supply chain, showing where export exposure and domestic price instability overlap.

İrfan Kadıoğlu explores these questions in "CBAM Cost Exposure and Farm Input Price Risk in the Fertiliser Value Chain: A Two-Level Soft-Set and Multi-Criteria Analysis for Türkiye," published in Sustainability. The study compares 21 non-EU suppliers across six fertiliser products using trade data from 2023–2025, then examines 16 Turkish agricultural input groups between January 2020 and July 2026. Its calculations bring together carbon charges, market conditions, price behaviour and estimated spending weights to identify the products deserving closer attention.

Türkiye offers a revealing case because its fertiliser industry depends on imports for more than 90% of its raw materials, according to the paper's background evidence. The analysis finds above-average modelled carbon-cost exposure for its exports and particularly high price risk for fertilisers purchased by farmers. These are separate findings linked by product categories, with no evidence from this study that export carbon charges caused domestic prices to rise.

A carbon bill concentrated in three products

The EU's Carbon Border Adjustment Mechanism, or CBAM, places a carbon cost on emissions embedded in covered imports, including fertilisers. The paper models charges using official default emissions values and a reference carbon price of €79.07 per tonne of carbon dioxide equivalent. Applied to Türkiye's historical export basket under 2030 rules, the calculated charge equals 32.6% of export value, compared with a supplier average of 22.9%.

Ammonia, urea and calcium ammonium nitrate account for 77.4% of Türkiye's covered export value and 93.9% of its modelled carbon charge. Calcium ammonium nitrate alone contributes 66.5% of the charge, making it the clearest concentration of export exposure. Türkiye's default emissions values sit close to the averages for comparable products, meaning its high overall burden largely reflects the fertilisers it sells.

The reference scenario produces an annual equivalent charge of $47.1 million at average 2023–2025 trade volumes, rather than a forecast of actual payments in 2030. The modelled cost-to-value ratio rises from 24.2% under 2026 rules to 41.9% under 2034 rules as the allowance deduction disappears. Testing carbon prices of €60 and €110 changes the size of the bill without changing supplier rankings, a result of the model applying the same price multiplier across suppliers.

Strong sales can hide carbon exposure

Türkiye's position looks stronger when buyers consider its growing market presence and broad product range alongside carbon costs. Its overall ranking ranges from first to seventeenth across methods and specifications, compared with eighteenth out of 21 when only carbon criteria are considered. Giving carbon criteria half the total weight pushes Türkiye into ninth to eighteenth place, showing how much the answer depends on buyers' priorities.

Morocco and Algeria appear among the top three suppliers in the combined rankings under both main specifications, supported by favourable carbon costs and market attributes. Egypt leads the baseline combined ranking, and Russia benefits when market size receives more weight than trade-policy risk. The United States and Oman sit among the bottom four in both combined rankings, reflecting their weaker positions under the study's chosen criteria.

The researcher compared several ranking approaches, including Relational Membership Value Calculation, known as RMVC, which builds on whether alternatives meet specified thresholds. RMVC reduced tied scores, but simulated tests showed no advantage over the simpler Maji–Roy method in identifying the best three alternatives when ties were treated fairly. Methods that allow strengths in one area to offset weaknesses elsewhere generally performed better when those trade-offs matched the underlying preferences.

Fertiliser prices put farm planning under strain

Straight and compound fertilisers occupy the first two places across all twelve full-period price-risk rankings, including checks that remove common inflation. Their prices rose faster than agricultural inputs overall and showed strong links with global energy prices, alongside above-average co-movement with exchange rates. Much of their risk comes from unpredictable fluctuations and unusually large increases, rather than steady cost pressure alone.

The longer record does not describe every recent period equally well, with both fertiliser groups falling to fourth place under RMVC for 2023–2026. Resampling the monthly data produced broad ranking ranges, indicating that fertilisers' lead over other inputs is less certain than the full-period results suggest. The observed links with energy and exchange rates describe prices moving together, without measuring how much either factor caused fertiliser prices to change.

An input's importance changes when its share of spending enters the comparison, bringing concentrate feed into the leading group alongside fertilisers. Estimated 2020 basket weights put concentrate feed at 23.6%, energy and lubricants at 17.5%, and the two fertiliser groups together at 10.1%. These reconstructed index weights are neither officially published group weights nor the current budgets of individual farms.

Lower emissions offer a route worth examining

A model scenario cutting Türkiye's default emissions values uniformly by 25% reduces its calculated 2030 charge by 32.2% and lowers the cost-to-value ratio to 22.1%. Türkiye moves from eleventh to fifth under the baseline RMVC ranking, illustrating how lower emissions could improve its position. The reduction is a modelling threshold, with no claim that it represents an achievable national target or a proven investment outcome.

The paper identifies plant-level emissions verification and measures such as reducing nitrous oxide from nitric acid production as priorities for closer examination. Replacing default values requires reliable production and precursor data, appropriate verification and information sharing throughout the supply chain. Compound fertilisers deserve domestic price monitoring despite their smaller carbon exposure, because their farm-input risk remains high.

The findings depend on default emissions, historical trade, estimated spending weights and ranking priorities that were not collected directly from buyers or farmers. Plant-level emissions records, detailed farm costs and evidence tracing price changes through the supply chain would help establish whether cleaner export production could ease domestic pressures. The research identifies where attention belongs, with calcium ammonium nitrate and ammonia prominent on the export side and fertilisers and concentrate feed prominent in farm-budget risk.