Brussels: Europe’s carbon border levy has crossed the line that separates ambition from administration. Since 1 January 2026 the Carbon Border Adjustment Mechanism has been in its definitive phase, meaning importers of steel, aluminium, cement, fertiliser, electricity and hydrogen must now buy certificates covering the emissions embedded in what they bring into the bloc. The principle is elegant. The execution, as a public consultation that closed on 10 June made clear, is where the mechanism either succeeds or quietly leaks away.
The logic of CBAM is to defend the EU’s domestic carbon price against an obvious escape route. If European producers pay for their emissions while importers do not, production simply migrates to jurisdictions with looser rules, and global emissions fall not at all. This is carbon leakage, and a border charge that mirrors the internal price is meant to close the door. In theory it levels the field; in practice its integrity depends entirely on the granular rules that decide how embedded emissions are measured, who certifies them and how easily the whole edifice can be gamed.
That is why the Commission spent the spring consulting on an implementing act aimed squarely at circumvention. The vulnerabilities are not hypothetical. A producer can ship goods through a third country to disguise their origin. An exporter can route only its cleanest output to Europe while selling dirtier production elsewhere, a practice known as resource shuffling that lowers the paper figure without lowering a single tonne of actual emissions. Default values set too generously can reward opacity, since a firm that refuses to disclose real data may end up paying less than one that honestly reports a high carbon footprint. Each loophole, left open, converts a climate instrument into a paperwork exercise.
The strengthening measures now under consideration try to anticipate these manoeuvres rather than chase them after the fact. Tighter origin tracing, stricter verification of supplier data, and default values calibrated to discourage non-disclosure are the unglamorous machinery on which the policy’s credibility rests. None of this generates headlines, yet it determines whether a tonne of carbon priced in Europe stays priced when it crosses the frontier. A border mechanism is only as strong as its weakest customs declaration.
There is a diplomatic dimension that the technical detail tends to obscure. CBAM is, from the perspective of many trading partners, a unilateral charge on their exports dressed in environmental language. Developing economies in particular argue that they are being asked to shoulder the cost of a transition designed and timed by the wealthy bloc that industrialised first. The harder Brussels tightens the rules against circumvention, the sharper that grievance becomes, because stricter enforcement falls heaviest on producers with the least capacity to measure and certify their emissions. Managing CBAM is therefore not only an exercise in customs engineering but in trade diplomacy, and the two pull in opposite directions.
The instrument also sits in delicate relationship with the EU’s own industry. CBAM was always the companion to phasing out the free emission allowances that European heavy industry has long received. As those free allowances are withdrawn, the border charge is supposed to take their place as the shield against unfair competition. If the mechanism is riddled with loopholes when that transition bites, European steelmakers and cement producers will find themselves paying the full domestic carbon price while imports slip through underpriced, the precise outcome the policy exists to prevent. The timing of the strengthening effort is no accident; it must be watertight before the protective scaffolding of free allowances is removed.
Whether tighter rules can outpace the ingenuity of those who wish to avoid them is the open question. Carbon accounting at a global scale is genuinely hard, and every rule invites a workaround. The consultation that ended on 10 June will not settle the matter so much as mark another round in a contest that will run for years. What it does confirm is that the difficult phase of CBAM has begun. The bloc has built its carbon wall. Now it has to find every crack before someone else does.
