CBAM makes supplier emissions data a commercial question

What changed in 2026

CBAM has applied under its definitive regime since 1 January 2026. It covers cement, iron and steel, aluminium, fertilisers, electricity and hydrogen. The legal obligation sits with the EU importer. Anyone bringing more than 50 tonnes of covered goods into the EU in a year must be an authorised CBAM declarant, report the emissions embedded in those goods and surrender certificates to match.

The money starts to move in 2027. Certificates go on sale on 1 February 2027, priced from EU Emissions Trading System auction prices, and the first annual declaration, covering 2026 imports, is due by 30 September 2027. The share of embedded emissions that is charged begins at 2.5% for 2026 and rises to 100% by 2034, as free allowances for EU producers are phased out.

Why the exporter still carries the work

The importer files the declaration, but the numbers in it come from the producer. Importers are asking suppliers for emissions per tonne of product at the level of the individual installation, split into direct and indirect emissions, together with the production route, the emissions embedded in purchased precursor materials and evidence of any carbon price already paid in the country of production.

Where a producer cannot provide figures checked by an accredited verifier, the importer falls back on default values published by the Commission. Those defaults are set conservatively. A producer with verified data below the default therefore lowers its customer's cost, and a producer without it raises that cost.

The early evidence

A study published in Nature Climate Change in June 2026 looked at Indian steel exporters during CBAM's reporting phase, which began in October 2023. High-emission firms reduced their exports to the EU by about 5% in quantity and 9% in revenue relative to low-emission firms, which held their export levels. The charge had not yet started. Buyers were already sorting their suppliers.

A supply chain data problem

Embedded emissions do not stop at the plant gate. They include the precursor materials a producer buys in. An exporter therefore needs emissions data from its own suppliers, collected and kept with the same discipline as tax registrations and bank details. That makes CBAM a job for the purchasing function as much as for the sustainability team.

Five things to do now

1. Map your exposure. List the products you sell into the EU by customs code, and the customers who will need data from you.
2. Build figures per installation. Measure by plant and production route, and line up an accredited verifier early.
3. Collect precursor data from your suppliers. Add emissions questions to supplier registration and qualification, and keep the evidence.
4. Bring emissions into sourcing decisions. Add emissions intensity as a criterion in sourcing events, alongside price and delivery.
5. Agree the format with EU customers. Settle what they need, in what form and by when, before their first declaration falls due.

The takeaway

In 2026 the charge itself is small. The sorting of suppliers is not, and it has already begun. Producers who can show verified, lower emissions will find that the data is worth more than the certificates it saves.