The Carbon Trust Standard — and what replaced it

One certified organisation published enough detail to see the shape of an assessment. Cadent, the UK’s largest gas distribution network, announced Taking Action certification in February 2024.

Its own announcement records an 11% reduction in carbon emissions over the three-year period of assessment, and a positive result on the carbon management assessment across governance, implementation, measurement and stakeholder engagement.

Two things are worth drawing out, and neither is a criticism of the company. First, the assessment period is three years, not one — so the certificate speaks to a trend rather than a single year, which is a strength. Second, and more surprising, the announcement describes the Carbon Trust as assessing Cadent as “working towards” the first tier.

“Working towards” the entry tier, announced as achieving certification, is a fine distinction that will not survive into a tender summary. It is the clearest available illustration of why the tier — and the exact wording of the certificate — is the thing to ask for.

The carbon management assessment is the underrated half. It scores governance and process, not just tonnes, which is closer to what a procurement team actually wants to know.

⚠ This example is a customer’s published announcement, not a Carbon Trust document. It is cited for what that company said about its own certificate, and nothing is inferred from it about the Standard’s general requirements.

The Carbon Trust publishes the rules. Not a summary, not a brochure: a technical specification with a version number, an issue date and a twenty-six section contents list, downloadable by anyone.

Organisational carbon footprints: Requirements for assurance, Part 1: Technical — version 1.0, issued 20 September 2024.

It states its own audience in terms: “This document is intended to be used by both the Carbon Trust and external parties.” A prospective customer, a sceptical procurement team, or a competitor can read exactly what conformity requires before spending anything.

The contents are what you would want them to be: organisational boundary and the equity-share, financial-control and operational-control approaches; the operational verification boundary; emission factors; Scope 2 treatment; allocation; land-based emissions and removals; biogenic carbon; baseline year and rebaselining policy; primary versus secondary activity data; materiality and cut-off criteria; evidence requests, site visits and re-verification.

That is the document this site said was missing elsewhere in this market. Here it is, published, versioned and dated.

There is a matching Part 2 for claims, and an equivalent pair for product footprints. The existence of these documents is the strongest single argument for taking a Carbon Trust verification seriously, and it deserves to be said as plainly as any criticism on this page.

The requirements set a floor and then let the customer choose above it. An organisation “shall choose the operational verification boundary (including Scope 1 and 2 emissions at a minimum), or shall have already a verified Scope 1 and 2 footprint where the organisation wishes for a Scope 3 footprint to be verified”.

So Scope 3 is verifiable, and it is optional — and a certificate does not tell you on its face which was chosen. Ask.

Conformity is required not to one standard but to a stack: the GHG Protocol Corporate Accounting and Reporting Standard, the Scope 2 Guidance, the Corporate Value Chain (Scope 3) Standard, the Land Sector and Removals Guidance, and PCAF’s financed-emissions standard where relevant.

That last one matters more than it looks. A financial institution’s emissions are overwhelmingly financed emissions, and naming PCAF in the requirements is the difference between a scheme that can handle a bank and one that cannot.

The requirements also carry an explicit note that the Land Sector and Removals Guidance section will be rewritten once that guidance is finally published — a standard saying out loud which of its own parts is provisional.

Verification runs in two stages: a calculation-data-input stage where the aggregated data is submitted, then a transaction-level stage with evidence sampling, methodological checks, and a site visit. Re-verification of subsequent years has its own section.

The product requirements contain a short list of what may not be counted, and the first item on it is the one that separates a serious reduction claim from a purchased one.

“Reductions which are not eligible for the claim: • Use of offsets.”

That is the same principle the original 2008 Standard was built on — “No exaggeration or embellishment. No offsetting” — carried into the current documents. Reductions must come from actions within the organisation’s control or influence, and there is a separate, explicit route for reductions from outside it, such as grid decarbonisation, which must be identified as such.

Claim periods are fixed: two years for achieved reductions and two for planned reductions, with re-verification against the most recent year at the end of it. A validated forward-looking claim runs one year.

And there is a realism clause. From the third verification onwards, a footprint that has not increased may be acceptable in place of a reduction — with justification required.

Read that clause carefully before quoting it either way. It is not a loophole: it applies from the third verification, it requires the footprint not to have risen, it requires written justification, and the organisation must show the actions it took over the previous twenty-four months. It is a rule for a business that has already taken the cheap reductions.

Alongside the organisational certification the Carbon Trust runs a labelling scheme — the part of its work most people have actually seen, on packaging.

The label set covers a product carbon footprint label, an assured model label, an organisational carbon footprint label, and participation in Amazon’s Climate Pledge Friendly programme.

The claims attached to a label are defined in the requirements documents rather than left to marketing: for organisational footprints the named claims are ‘reduced’ and ‘reduced and climate projects funded’. The second is the careful construction that replaced carbon-neutral language — funding climate projects is stated as a separate fact, not folded into the reduction.

A footprint can also be verified without the right to use the logo. That is a real distinction: a verification letter is a statement about your numbers; a label is a licence to make a claim in public, with usage guidelines attached.

So “verified by the Carbon Trust” and “carries the Carbon Trust label” are different statements, and the requirements treat them differently.

There is a public label directory listing the products that carry it, which is the right shape of transparency for a consumer-facing mark.

This page is more favourable to its subject than the one next door on Planet Mark, and the reason is worth stating rather than leaving implied: the Carbon Trust publishes the rules it certifies against.

Everything critical below is drawn from documents the Carbon Trust put in public itself. That is the point. A scheme that publishes its requirements can be checked, argued with, and held to them. A scheme that does not, cannot.

The criticism here is narrow: a name mismatch, and a tier that gets dropped when the claim is repeated.

This page does not say the Carbon Trust Standard was withdrawn. No retirement notice was found, and none is asserted. It records that the live organisational certification is the Route to Net Zero Standard, and that the page carrying the older name reads “Last updated November 2021”.

It does not say a Route to Net Zero certificate is weak. Tier one requires demonstrated historical reductions and a carbon-management assessment, which is more than most marks ask. It says an unqualified claim cannot tell you which tier was met.

And it does not say the Carbon Trust is not independently accredited. The structure is set out at chapter twelve, from the Carbon Trust’s own scheme document, with the one qualification that document itself contains.