What is CBAM? It’s the EU’s way of making sure imported steel, cement, aluminium, and other carbon-intensive goods pay a carbon price close to what European producers already pay — and here’s exactly what that means for your business.

In this article:

• The problem CBAM was built to solve (carbon leakage, in plain terms)
• What CBAM actually is — and why it isn’t a tariff
• Who has to comply, who’s exempt, and the timeline from “learning phase” to full obligations
• Which goods and sectors are in scope, at a high level
• How the certificate obligation is worked out, without the algebra
  

If you run a business that imports steel, cement, aluminium, fertiliser, hydrogen, or electricity into the European Union — or sell any of those things to a company that does — you’ve probably heard the acronym CBAM lately. Maybe your customs broker mentioned it, or a customer overseas asked for “embedded emissions data” and you had no idea what that meant.

I want to walk through this from the beginning, the way I’d explain it to a colleague in finance or ops who has never touched a carbon report. By the end you should understand what CBAM is, why it exists, and roughly how it affects a business like yours.

What Is CBAM?

To understand CBAM, you first need to understand a problem the EU has been wrestling with for years: carbon leakage.

The EU runs a carbon market called the EU Emissions Trading System, or EU ETS. Under it, European factories that make carbon-intensive products — steel mills, cement plants, aluminium smelters — have to buy and hand over “allowances” for every tonne of CO2 they emit. That costs real money, and it’s meant to push those industries toward cleaner production.

Here’s the catch. A factory in a country without an equivalent carbon price doesn’t face that cost, so it’s cheaper to make steel outside the EU and ship it in than to make it inside the EU and pay for the emissions. That price gap creates a nasty incentive: EU industry can simply move production — and the emissions that go with it — somewhere else, then sell the finished product back into the EU market. The emissions haven’t gone away, they’ve just moved. That’s carbon leakage, and it’s the exact loophole CBAM exists to close.

So What Exactly Is CBAM?

CBAM stands for Carbon Border Adjustment Mechanism. In one sentence: it’s an EU policy that requires importers of specific carbon-intensive goods to pay a carbon cost roughly equivalent to what an EU-based producer of the same good would pay under the EU ETS.

A few things worth being precise about, since this is where people get it wrong most often:

• CBAM is not a tariff. A tariff is a flat tax on a category of goods regardless of how they were made. CBAM is priced to the actual carbon footprint of the specific goods — a low-emission steel producer pays less than a high-emission one, even in the same category.
• CBAM does not target countries. It targets the embedded emissions of specific products, from any country outside the EU, applied the same way regardless of origin.
• CBAM mirrors the EU ETS rather than creating a separate tax regime. The goal is that an EU producer and a non-EU producer selling into the EU face a comparable carbon price — no more, no less.

One more mechanic worth knowing: EU industries at carbon-leakage risk have historically received a chunk of their EU ETS allowances for free, as a competitiveness cushion. As CBAM phases in, that free allocation is being phased out in parallel — so CBAM isn’t only about charging importers, it’s also about retiring a legacy subsidy for EU producers.

Who Actually Has to Comply

The legal responsibility sits with the importer — the “authorised CBAM declarant,” usually the company lodging the customs declaration, or an indirect customs representative acting on its behalf. Every tonne of an imported CBAM good has exactly one declarant responsible for it.

A detail that surprises people: the non-EU factory that actually makes the goods has no legal obligation under CBAM at all. Foreign producers aren’t required to measure, verify, or report anything to the EU. If they don’t cooperate, the EU importer falls back on standardized “default values” from the European Commission — conservative figures that can push the cost higher than a producer’s real, verified footprint would. That makes emissions data a competitive lever, not just a compliance checkbox: a supplier willing to verify its actual numbers can hand its EU customers a lower bill than one that isn’t.

A few categories are exempted outright: importers whose total CBAM-goods imports stay under 50 tonnes a calendar year (doesn’t cover electricity or hydrogen); goods for specific military uses; and imports from Norway, Iceland, Liechtenstein (which apply the EU ETS directly) or Switzerland (linked ETS) — producers there already face a comparable carbon price.

The CBAM Timeline: From Reporting to Real Money

CBAM rolled out in two phases, not all at once.

The first was a transitional period, running from October 2023 through the end of 2025 — a “learning phase,” in the European Commission’s own words. Importers had to report the embedded emissions of goods they brought in every quarter, but didn’t have to pay anything. Think of it as a dry run: build the reporting muscle before the bill shows up.

That phase is over. We’re now in the definitive period, which began 1 January 2026 — this is where the financial obligation kicks in, and importers must buy and surrender CBAM certificates tied to embedded emissions. Reporting also shifted from quarterly to an annual declaration, with the first one due by 30 September 2027, covering imports from calendar year 2026.

The certificate obligation doesn’t jump straight to 100% either. It phases in gradually between 2026 and 2033, in step with the phase-out of that free EU ETS allocation, rising each year. From 2034 onward, 100% of embedded emissions in covered goods are subject to CBAM certificates, and free allocation for those goods disappears entirely.

The diagram below shows the CBAM rollout on a single timeline, from the reporting-only learning phase through to full financial enforcement in 2034.

A note on precision: the exact year-by-year percentage sits in the CBAM Regulation and its implementing acts; early guidance cites a specific 2026 figure only as an illustration, not a headline number. The direction — rising steadily to 100% by 2034 — is settled; treat the precise annual figure as one to confirm before you cite it.

Which Goods and Sectors Are Covered

CBAM applies to six sectors, chosen because they sit within the EU ETS and are most exposed to carbon leakage:

CBAM also reaches “precursors” — inputs used to make a covered good — and certain downstream products made from them. A company importing a finished product containing, say, a steel component may be in scope even if “steel” isn’t the headline item on the invoice. The full, legally binding list of covered product codes lives in the CBAM Regulation; it’s detailed enough to deserve its own post later in this series.

How the Obligation Actually Gets Calculated

This is the part that scares people off, because the official formula looks like an engineering equation. The logic behind it is straightforward. For each imported good, it works in three steps:

1. Start with the real carbon footprint — how much CO2 was emitted making this shipment, or a conservative EU-set default if that data isn’t available.
2. Subtract two credits: the “free allocation” credit (the phase-in adjustment above, mirroring what an equivalent EU factory would still get that year), and any carbon price the foreign producer already paid at home, so it isn’t charged twice.
3. Multiply what’s left by how much you imported. The result — never below zero — is the number of CBAM certificates owed, one per tonne of CO2-equivalent emissions.

“Embedded emissions” itself has two components: direct emissions (from making the good, including the energy to heat or cool it) and indirect emissions (from the electricity used to make it). For imported electricity, only direct emissions count.

The flow below traces a shipment from a non-EU factory through to certificate surrender — showing where emissions data comes from and where it can be replaced by defaults if a supplier doesn’t provide it.

The certificate price itself isn’t arbitrary — it tracks the EU ETS, calculated as the yearly average of EU carbon allowance prices. As the EU’s own carbon price moves, so does the cost of CBAM certificates.

Transitional vs. Definitive Period, at a Glance

How Sprih Helps

If there’s one thing that becomes clear once you look past the customs paperwork, it’s this: CBAM is fundamentally a supply-chain emissions-data problem, not a tax-filing exercise. The number that determines your certificate bill lives inside your suppliers’ factories, not your finance system — and chasing it down, shipment by shipment, supplier by supplier, is where most companies get stuck.

That’s the layer we’ve spent our time building. Sprih’s core platform, SustainSense, already indexes emissions and sustainability data across more than 120,000 companies and 400,000 reports, giving teams a way to see and act on climate data at scale rather than assembling it from scratch every quarter. We’re extending that same infrastructure into CBAM-specific tooling, built to help importers and their suppliers calculate, verify, and manage embedded-emissions data as this obligation scales through 2034.

If you’re trying to figure out what CBAM actually means for your import book, we’d be glad to talk it through.

Sprih is an AI-native sustainability intelligence company helping enterprises turn climate and compliance data into competitive advantage.