ISO 14064 vs GHG Protocol: differences, mapping and verification
ISO 14064 vs GHG Protocol is less a choice than a question of fit: the GHG Protocol is the most widely used method for building a corporate greenhouse gas inventory, while ISO 14064 is an international standard series that covers the inventory (ISO 14064-1), projects (ISO 14064-2) and the verification of GHG statements (ISO 14064-3). The two share the same core principles, and one well-built inventory can usually meet both. The differences lie in how emissions are categorised, what must be documented and how the inventory is verified.
What each standard is
The GHG Protocol
The GHG Protocol is a family of standards and guidance developed by the World Resources Institute and the World Business Council for Sustainable Development. For companies the core documents are the Corporate Standard, the Scope 2 Guidance (2015) and the Corporate Value Chain (Scope 3) Standard (2011). It is free to use and is the reference point for most disclosure frameworks, including ISSB's IFRS S2, ESRS, CDP and SBTi target setting. It organises emissions into Scope 1, Scope 2 and Scope 3, with Scope 3 split into 15 categories.
The ISO 14064 series
ISO 14064 is published by the International Organization for Standardization in three main parts:
- ISO 14064-1:2018 — specification for quantifying and reporting GHG emissions and removals at organisation level.
- ISO 14064-2:2019 — specification for GHG projects that reduce emissions or enhance removals.
- ISO 14064-3:2019 — specification for the verification and validation of GHG statements, applicable to organisation, project and product statements.
Related documents complete the picture: ISO/TS 14064-4:2025 gives guidance on applying ISO 14064-1, ISO 14065 sets requirements for the bodies that validate and verify, and ISO 14067 covers product carbon footprints. The series is programme-neutral: a regulator or scheme that uses it can add its own requirements on top.
ISO 14064-1 vs the GHG Protocol: side by side
| Topic | GHG Protocol Corporate Standard | ISO 14064-1:2018 |
|---|---|---|
| Type | Accounting and reporting standard with extensive guidance | International standard with "shall" requirements and guidance |
| Access | Free | Purchased from ISO or national standards bodies |
| Emission grouping | Scope 1, Scope 2, Scope 3 (15 categories) | Six categories: direct; indirect from imported energy; transportation; products used by the organisation; use of the organisation's products; other indirect |
| Indirect emissions | Scope 2 required; Scope 3 reporting optional under the Corporate Standard, with a separate Scope 3 Standard | Indirect emissions must be assessed for significance, and significant ones quantified and reported |
| Scope 2 methods | Location-based and market-based both required where applicable | Annex guidance on electricity accounting; how location- and market-based figures are reported should be agreed with your verifier |
| Removals | Reported separately from the scopes, with dedicated land sector and removals guidance | Removals quantified and reported within the inventory |
| Uncertainty | Encouraged, with guidance | Uncertainty assessment required |
| Inventory management | Guidance on quality management | Requirements for information management and documentation |
| Verification | Not specified; companies choose an assurance standard | Paired with ISO 14064-3 for verification |
| Common uses | CDP, SBTi, ISSB/IFRS S2, ESRS, BRSR, customer requests | Verified inventories, government and programme schemes, tenders |
The table summarises the main structural differences. Detailed requirements, such as the treatment of biogenic CO2 or the reporting of base-year recalculations, differ in wording; check the standards themselves for exact obligations.
Mapping categories to scopes
Because the grouping differs, one inventory needs a clear mapping. In broad terms:
- ISO Category 1 (direct emissions and removals) corresponds to Scope 1.
- ISO Category 2 (indirect emissions from imported energy) corresponds to Scope 2.
- ISO Categories 3 to 6 together correspond to Scope 3: transportation maps to upstream and downstream transport and travel; products used by the organisation maps to purchased goods, capital goods, fuel and energy-related activities and waste; use of the organisation's products maps to use and end-of-life of sold products; other indirect covers the rest.
The mapping is close but not one-to-one, so record the Scope 3 category and the ISO category against each emission source. That way both views come from the same entries, and nothing is counted twice.
GHG verification and ISO 14064-3
GHG verification is an independent check that a GHG statement is free of material misstatement and conforms to the criteria it claims. ISO 14064-3 sets out how this is done: agreeing the level of assurance (reasonable or limited), the objectives, criteria, scope and materiality; assessing risks; planning evidence-gathering; testing data and controls; and issuing a verification opinion. Verification bodies are commonly accredited against ISO 14065.
An important point is that ISO 14064-3 is not tied to ISO 14064-1. A verifier can apply it to an inventory prepared under the GHG Protocol, and many corporate GHG statements are verified this way. Financial auditors more often use ISAE 3410 or ISAE 3000, and the newer ISSA 5000 standard for sustainability assurance. In India, BRSR Core can be checked through assessment or assurance, and CCTS and CBAM have their own verification rules.
Whichever standard the verifier uses, the work looks similar: sampling entries, tracing them to source documents, recalculating with the stated emission factors and checking that the boundary is complete.
Which should you follow?
- Disclosure-led reporting (CDP, ISSB, ESRS, BRSR, SBTi): build on the GHG Protocol, because these frameworks reference it directly.
- A verification statement against an international standard, or a tender or programme that names ISO: prepare the inventory to ISO 14064-1 and have it verified to ISO 14064-3.
- Both: the most common case. Build one inventory that meets the stricter requirement on each point (for example, uncertainty assessment from ISO and dual Scope 2 reporting from the GHG Protocol), and tag each source with both its scope and its ISO category.
Convergence: one standard in future
The GHG Protocol and ISO announced a strategic partnership in September 2025 to harmonise their corporate carbon accounting standards. In July 2026 they said they would combine the GHG Protocol's Scope 1, Scope 2, Scope 3 and Actions and Market Instruments standards with ISO 14064-1 into a single co-branded corporate standard, with an integrated public consultation planned for 2027. Until a new standard is published and adopted, the current versions apply. ISO 14064-1:2018 was confirmed in 2024 and is also listed by ISO as under revision. Inventories that are already consistent with both standards will be best placed for the change.
How EKOTRACE helps
EKOTRACE builds GHG Protocol and ISO 14064-1 inventories from the same approved data. Each source is tagged with its scope, Scope 3 category and ISO category, and Scope 2 is calculated on both location- and market-based methods. Emission factors are versioned, every entry carries its evidence and maker-checker approval, and the audit trail records every change. That gives your verification body the evidence it needs for ISO 14064-3 sampling without a trail of spreadsheets. See GHG accounting, our guide to Scope 1, 2 and 3 and EKOTRACE.
Frequently asked questions
Is ISO 14064 the same as the GHG Protocol?
No, but they are closely aligned. Both rest on the principles of relevance, completeness, consistency, accuracy and transparency, and both distinguish direct from indirect emissions. ISO 14064-1 uses six categories and sets formal requirements, while the GHG Protocol uses three scopes and is the basis for most disclosure frameworks.
Can a GHG Protocol inventory be verified to ISO 14064-3?
Yes. ISO 14064-3 sets out how to verify a GHG statement against stated criteria, and those criteria can be the GHG Protocol. Many companies report under the GHG Protocol and obtain an ISO 14064-3 verification statement.
Is ISO 14064 certification mandatory?
Not generally. Verification to ISO 14064-3 is voluntary unless a regulator, programme, customer or tender requires it. Note that the output is a verification statement on a GHG inventory, not a certification of the company.
What is the difference between ISO 14064-1 and ISO 14064-3?
ISO 14064-1 tells an organisation how to quantify and report its GHG emissions and removals. ISO 14064-3 tells a verifier how to check such a statement and form an opinion on it.