Getting Verification-Ready for ISO 14064-3 — Before the Auditor Arrives
A report that is calculated correctly but cannot be proven is worth the same as one that is wrong — ISO 14064-3 defines what proof must look like and what organizations should prepare.
A carbon report used for official submission or public disclosure must be verified by an independent body under ISO 14064-3. As many organizations learn the hard way, the heavy lifting is not the audit visit — it is assembling a year's worth of evidence afterwards.
What verifiers ask for
- Source evidence behind every figure — utility bills, fuel receipts, meter logs
- The origin and version of every emission factor
- A change history: who edited which number, when, and why
- A consistent organizational boundary and consolidation approach throughout
Why spreadsheets struggle
Files pass through many hands, formulas change without a trace, and nothing marks which dataset has already been reviewed. When a number changes after sign-off, the entire chain becomes questionable.
In GCarbon
Every activity carries a verification status (UNVERIFIED → UNDER_REVIEW → VERIFIED / REJECTED), and any edit automatically rolls the status back — making post-sign-off changes impossible to hide. External auditors get read-only access through a Verifier Portal, with a data room that gathers evidence, EF traceability and a standards-based verification statement template in one place.
“The verifier does not doubt your intent — they simply need a path from every number back to its evidence”
Choosing the assurance level before the audit
Verification comes at two levels: limited assurance, with analytical review and sampling, and reasonable assurance, which digs into nearly all source evidence. Cost and duration differ substantially. New reporters usually start limited and upgrade once the system stabilizes — but some submissions mandate a minimum level, so confirm before agreeing scope with your verifier.
After the audit — handling findings professionally
Verifier findings are not failures; they are the best improvement list your organization will receive. Record each with a root cause, fix the process rather than the individual number, and keep the remediation history for the next cycle. A verifier who sees last year's findings systematically closed extends visibly more confidence to the entire dataset.
GCarbon Team
Carbon accounting specialists
