The EU Carbon Border Adjustment Mechanism (CBAM) charging phase has begun. Free allowances phase out linearly to zero by 2034, and the first tranche covers six sectors: cement, steel, aluminium, fertilisers, electricity and hydrogen. Petrochemicals are not listed yet, but the rules set product carbon footprint (PCF) as a trade prerequisite, so exporters will pay sooner or later.

SNSUC's answer is to make carbon data verifiable. For each batch, emissions from extraction to discharge port are recomputed independently in the browser with SHA-256 and attested, so the buyer verifies rather than trusts. The fingerprint shares its source with the digital warehouse receipt, confirming title and carbon rights in one step.

Cross-chain receipt mutual recognition lets the same batch's carbon certificate be read by banks on both the Chinese and European sides. The letter of credit presentation attaches the carbon-footprint hash, so the negotiating bank skips paper-report checks and single-presentation time drops from two days to four hours.

Among the seven transshipment grades, long-haul seaborne grades such as Basrah Light and ESPO carry higher carbon intensity. Building PCF now lets future carbon cost fold into today's listing price, avoiding a forced takeover after 2034. Compliance is not a cost centre; it is pricing power.