- Home
- Insights
- GHG assurance
- What a GHG verifier actually examines
What a GHG verifier actually examines
Organisations preparing for a first verification usually expect a document request and a meeting. What arrives instead is a structured examination with a stated objective, defined criteria, a declared level of assurance, an assessed materiality and an evidence-gathering plan built from a risk analysis. This note describes that sequence as it is performed under ISO 14064-3:2019.
A verification tests an assertion, it does not produce one.
The subject of a verification is a GHG assertion made by the responsible party — an inventory, a project report, a product footprint, a neutrality claim. The verifier does not calculate it, correct it or improve it. The verifier plans and performs an examination sufficient to conclude, at a declared level of assurance, whether that assertion is materially correct and in conformity with stated criteria.
That distinction is the reason a verification body cannot also prepare the inventory it examines. Under ISO/IEC 17029:2019 and ISO 14065:2020 the impartiality of the body, and the separation of the engagement team from the independent reviewer and from the decision-maker, are conditions of the conclusion having any value at all.
Seven things established before a single figure is tested.
Objective, scope and criteria
What is being examined, over which period and boundary, and against which criteria — ISO 14064-1:2018, a programme methodology, a regulation, or a defined combination. Criteria that are not agreed in writing cannot be reported against.
AgreementLevel of assurance
Reasonable or limited. This is not a service tier — it determines the depth of testing, the sampling, and the wording of the conclusion.
DeclaredMateriality
The threshold at which an error, omission or misstatement would change a user's decision. It is set and documented before testing, not adjusted afterwards to fit a result.
Set in advanceStrategic analysis
Understanding the operations, the data flows and the systems that produce the assertion — which is where the risk actually sits.
UnderstandingRisk assessment
Inherent risk, control risk and detection risk, assessed per source and per data stream, not at the level of the organisation as a whole.
AnalysisEvidence-gathering plan
Sampling, analytical procedures, recalculation, walkthroughs and site work, sized against the assessed risk and the declared level of assurance.
PlanIndependent technical review
A competent reviewer who took no part in the engagement examines the file before any conclusion is issued. Then, separately, an authorised decision-maker decides.
Before issuance
What is examined, and what it is examined against.
| Area | What the verifier tests | Typical evidence |
|---|---|---|
| Boundary | That the organisational and reporting boundaries are stated, applied consistently, and reconcile to the legal and operational structure. | Consolidation approach, entity list, ownership records, site register |
| Completeness | That all significant sources and sinks inside the boundary are included, and that exclusions are stated and justified. | Process maps, utility register, asset list, prior-year comparison |
| Quantification | That the method, activity data and factors match the criteria and are applied consistently. | Calculation model, meter data, invoices, factor sources with versions |
| Data flow and controls | That the path from primary record to reported figure is intact, and that the controls on it operate. | Walkthroughs, access logs, reconciliation, review evidence |
| Base year | That the base year is defined and that the recalculation policy has been applied where structural change occurred. | Base-year statement, recalculation record, acquisition and disposal records |
| Uncertainty and estimates | That estimates are identified, that the basis is documented, and that the effect is understood. | Estimation methodology, sensitivity work, documented assumptions |
| Reporting | That the report contains what the criteria require it to contain, and claims nothing beyond it. | Draft GHG report, disclosure checklist, management representation |
Three ways an engagement ends.
An unmodified conclusion. The assertion is materially correct and conforms to the criteria at the declared level of assurance. The statement says what was examined, against what, at which level, within which boundary — and nothing more.
A modified conclusion. Something material remains unresolved, or the scope was limited in a way that could not be worked around. The modification is stated plainly and its cause is described. This is a legitimate outcome, not a failure of the process.
No conclusion. The evidence does not permit one. Where an engagement cannot be completed, the body withdraws rather than issuing a statement it cannot support. A verifier who will always find a way to sign is telling you something about the value of the signature.
Primary sources
- ISO 14064-3:2019 — Specification with guidance for the verification and validation of greenhouse gas statements — www.iso.org/certification.html (checked 01 September 2026)
- ISO 14064-1:2018 — Specification with guidance at the organization level for quantification and reporting of GHG emissions and removals — www.iso.org/certification.html (checked 01 September 2026)
- ISO/IEC 17029:2019 — General principles and requirements for validation and verification bodies — www.iso.org/certification.html (checked 01 September 2026)
- ISO 14065:2020 — General principles and requirements for bodies validating and verifying environmental information — www.iso.org/certification.html (checked 01 September 2026)
- ISO 14066:2023 — Competence requirements for teams validating and verifying environmental information — www.iso.org/certification.html (checked 01 September 2026)
Editorial note. Author and technical review above are editorial functions. They are separate from the independent technical review and the decision functions required under ISO/IEC 17029:2019, which apply to validation and verification engagements and not to published articles. Nothing on this page is advice on a specific engagement, and nothing here extends or replaces the accreditation records.
Read next
Describe the claim — not the service.
Tell us what must be relied on, who will rely on it and by what date. We will confirm the correct programme, evidence requirement and responsible entity — or tell you it is outside our scope.