What is ISO 14064-1? GHG inventory and verification explained
ISO 14064-1 is an inventory standard, not a management system certificate. The six categories, inventory steps, ISO 14064-3 verification, levels of assurance, and how it differs from CBAM verification.
ISO 14064-1 is the international standard that sets out how an organization quantifies and reports its greenhouse gas emissions and removals. The current edition dates from 2018, and ISO reviewed and confirmed it in 2024. One detail matters more than any other: unlike ISO 9001, it does not lead to a management system certificate. The organization prepares its inventory, an independent verifier examines it under ISO 14064-3, and the verifier issues an opinion for a specific reporting period.
What the market calls an "ISO 14064 certificate" is usually that verification statement. The difference shapes your budget, your schedule and what you can actually send to a customer who asks for proof. This guide covers the structure of the standard, the six categories, the inventory steps, how verification works, and how it differs from mandatory verification in Turkey and from CBAM verification. If you buy from Turkish suppliers, the last comparison will help you ask for the right document.
What does each ISO 14064 standard do?
"ISO 14064" is not a single document. Separating the numbers tells you who does what:
| Standard | Subject | Who it concerns |
|---|---|---|
| ISO 14064-1:2018 | Quantifying and reporting emissions and removals at organization level | The organization preparing the inventory |
| ISO 14064-2:2019 | Emission reductions and removal enhancements at project level | Reduction project developers |
| ISO 14064-3:2019 | Verification and validation of GHG statements | Verifiers, and indirectly the organization |
| ISO 14065:2020 | Requirements for bodies validating and verifying environmental information | Verification bodies and accreditation bodies |
| ISO 14066 | Competence of validation and verification teams | Verification bodies |
In short, your company prepares under 14064-1 and the verifier examines under 14064-3. The verifier's own capability is assessed through 14065.
What are the six categories of ISO 14064-1?
ISO 14064-1:2018 groups emissions into six categories. If you know the three scopes of the GHG Protocol, the mapping below will help. We explain the scope logic in Scope 1, 2 and 3 emissions explained.
| Category | Content | Example at a plant | GHG Protocol |
|---|---|---|---|
| 1 | Direct emissions and removals | Boilers, furnaces, company vehicles, process emissions, refrigerant leaks | Scope 1 |
| 2 | Indirect emissions from imported energy | Grid electricity, purchased steam | Scope 2 |
| 3 | Indirect emissions from transportation | Third-party freight, staff shuttles, business travel | Scope 3 |
| 4 | Indirect emissions from products the organization uses | Raw materials, packaging, purchased services, waste | Scope 3 |
| 5 | Emissions associated with the use of the organization's products | Use and end of life of sold products | Scope 3 |
| 6 | Other indirect sources | Special cases that fit nowhere else | Scope 3 |
One rule is often missed. You do not have to quantify every indirect category automatically, but you do have to assess them all. The organization defines its significance criteria, quantifies the indirect sources it finds significant, and justifies what it leaves out. That justification is one of the first things a verifier reads.
How do you prepare an ISO 14064-1 inventory?
The standard rests on five principles: relevance, completeness, consistency, accuracy and transparency. In practice the work runs in this order:
- Organizational boundary. Decide which sites and companies are included, using a control or equity share approach.
- Reporting boundary. Sort sources into categories and put your significance criteria in writing.
- Source identification. List fuels, electricity, process emissions, refrigerants, logistics and purchases, site by site.
- Data and method. Collect primary data such as invoices, meter readings and weighbridge records, then choose an emission factor and global warming potential values for each source.
- Base year. Choose a comparison year and define in advance which changes trigger a recalculation.
- Uncertainty. Assess how reliable the results are and explain it in the report.
- Report and records. Prepare the report and retain the documents and calculation records.
The report covers the organization, the responsible person, the reporting period, the boundaries, results by category, the base year, methods, factors and uncertainty. It also states whether the report was verified and, if so, the type of verification and the level of assurance.
A spreadsheet can be enough for the calculation side. We look at where it starts to break in carbon accounting in Excel vs software.
How does the verification process work?
Going by the structure of ISO 14064-3, verification is not a one-day check at the end. It has planning, execution and completion stages:
| Stage | What happens | What you provide |
|---|---|---|
| Pre-engagement and contract | Scope, criteria, level of assurance and materiality are agreed. | Boundaries, site list, intended users of the report |
| Strategic analysis and risk assessment | The verifier studies your activities and where errors are most likely. | Process descriptions, data flow, last year's report |
| Verification and evidence-gathering plans | They define what will be tested, how, and whether a site visit is needed. | People to interview, access to records |
| Site visit and evidence gathering | Invoices, meters and calculations are examined on a sample basis. | Source documents, calibration records, factor sources |
| Evaluation of findings | Misstatements and non-conformities are raised. | Corrections and explanations |
| Independent review and opinion | Someone not involved in the work reviews the file, and the opinion is issued. | Final report |
Quoting a standard duration or fee would mislead you. The drivers are the number of sites and categories, the sector, the level of assurance, any site visits and the state of your data. The verifier's first request is usually the same: "Show me where this figure comes from." Tidy evidence shortens the review.
Reasonable or limited assurance?
Level of assurance is one of the main choices in a verification contract. ISO 14064-3:2019 has a dedicated annex for limited assurance.
| Reasonable assurance | Limited assurance | |
|---|---|---|
| Level of confidence | High, but not absolute | Lower |
| Depth of work | More extensive testing and evidence | Narrower in nature, timing and extent |
| Wording of the opinion | Positive: the statement is free of material misstatement | Negative: nothing suggests a material misstatement |
| When it fits | A customer or programme requires it, or the inventory is mature | First year, internal targets, or where external users accept it |
The materiality threshold shows how large an error must be to change the conclusion. Published verification statements often use 5 percent, but do not treat that as a fixed rule. The threshold depends on the intended users and any programme, and it is settled in the contract.
How do you choose a verifier?
- Accreditation. Is the body accredited, and does its scope cover GHG statements under ISO 14064-1 and your sector? Ask for the scope document.
- Independence. A consultant who prepared your inventory cannot verify it. Raise conflicts of interest early.
- Your customer's expectations. If a buyer requires a certain level of assurance or a certain body, find out before you request quotes.
- Language and output. If the statement goes to customers abroad, confirm which languages it will be issued in.
Three verifications that are easy to confuse
Turkish manufacturers can now face three separate regimes at once. All three get called "GHG verification", but none replaces another:
| ISO 14064-1 verification | Turkish GHG report | CBAM verification | |
|---|---|---|---|
| Basis | Voluntary standard, ISO 14064-3 | Turkish ETS Regulation (27 August 2026, Official Gazette 33353) | EU CBAM legislation, Verification Regulation 2025/2546 |
| Coverage | Organization, six categories | Operators carrying out Annex 1 activities | Installation and CBAM goods, embedded emissions per product |
| Who verifies | A verifier you choose | A body accredited by TÜRKAK under ISO/IEC 17029 and appointed through the MEDAS system | An accredited verifier competent for CBAM |
| Assurance | Chosen in the contract | Reasonable | Reasonable |
| Timing | A period you define | Reporting by 30 April each year | First CBAM declaration by 30 September 2027 |
The Turkish regulation repealed the 2014 regulation on monitoring greenhouse gas emissions. Operators under Annex 1 must have their report verified before sending it to the Climate Change Directorate, and a voluntary ISO verification does not meet that duty. For the CBAM side, see how to prepare a CBAM report. Pilot dates and scope are in our Turkey ETS guide.
The good news is that the raw data behind all three is largely the same. Keep fuel, electricity and process records once, with their sources, and you can calculate from the same data under different boundaries and methods.
Will ISO 14064-1 change?
Yes, but not yet. On 29 July 2026 the GHG Protocol announced that it and ISO will combine the Scope 1, 2 and 3 standards and ISO 14064-1 into a single corporate standard. The timeline has a consolidated public consultation in the second quarter of 2027 and publication in the fourth quarter of 2028.
That is no reason to wait. ISO 14064-1:2018 remains the current standard. The sensible move is to keep data at source level rather than in report format, and to tag every record with both its category and its scope. When the report format changes, you will not have to collect the data again.
Most common mistakes
- Treating verification as a three-year certificate. The opinion applies to the stated period and statement.
- Dropping indirect categories without written significance criteria.
- Not recording the source and version of each factor and the global warming potential values.
- Choosing a base year without defining a recalculation rule.
- Counting a source twice when mapping categories to scopes.
- Calling a verifier only after the report is finished, when gaps in evidence cost the most to fix.
Where Carbonet fits
Carbonet is a corporate carbon footprint and CBAM software developed by LNA Soft in Izmir, Turkey. Software does not verify anything; an independent verifier does. Its job is to give that verifier a tidy, traceable file. In our ISO 14064 GHG inventory software, every record is tagged with both its ISO 14064-1 category and its GHG scope. You can choose IPCC AR5 or AR6 and DEFRA, EPA or TÜİK (Turkish Statistical Institute) factor sources, the source and factor version behind each figure stay on record, and all sites are tracked on one screen. The same fuel and energy data carries over to the CBAM embedded emissions calculation.
Building your first inventory or preparing for verification? Let us look at it together: request a demo, or write to info@carbonet.com.tr or WhatsApp +90 533 368 05 99.
Frequently asked questions
Can a company get ISO 14064 certified?
ISO 14064-1 is not a management system standard, so there is no certificate like ISO 9001. Your inventory is verified by an independent body under ISO 14064-3, which issues a verification opinion or statement. What people call a certificate is usually this statement.
Is ISO 14064-1 mandatory?
The standard itself is voluntary. Customers, lenders and large buyers may still ask for a verified inventory. Some jurisdictions have separate mandatory reporting, such as verification under Turkey's ETS Regulation for Annex 1 activities.
How long is a verification statement valid?
A verification opinion applies to a specific reporting period and a specific GHG statement, so it should not be treated as having a fixed validity term. Each new reporting year needs a new inventory and, where required, a new verification.
What is the difference between ISO 14064-1 and the GHG Protocol?
The GHG Protocol groups emissions into three scopes and ISO 14064-1 into six categories. The underlying logic is similar and the same inventory can be presented both ways. The two organizations are working on a single corporate standard, expected in the fourth quarter of 2028.
Does ISO 14064 verification replace CBAM verification?
No. ISO 14064-1 is an organization-level inventory, while CBAM requires embedded emissions per installation and product under its own verification rules. Fuel, electricity and process data feed both, so keeping it in one place cuts duplicate work.