ISO 14064: GHG Accounting and Verification

What It Is

ISO 14064 is an international standard for greenhouse gas accounting and verification, published by ISO. Its three core parts were most recently revised in 2018-2019, and two guidance documents have since joined the series: ISO/TS 14064-4 (2025) on applying Part 1 and ISO 14064-5 (2026) on verifying and validating remotely. It provides an internationally recognized framework for quantifying, monitoring, reporting, and verifying GHG emissions and removals at both organizational and project levels.

ISO 14064-1: Organization Level specifies principles and requirements for designing, developing, managing, reporting, and verifying an organization's GHG inventory. It covers direct emissions (comparable to Scope 1), energy indirect emissions (Scope 2), and other indirect emissions (Scope 3), using a categorization system aligned with but not identical to the GHG Protocol.

ISO 14064-2: Project Level specifies principles and requirements for determining baselines, monitoring, quantifying, and reporting GHG emission reductions and removal enhancements from specific projects. This is relevant for carbon offset projects, reduction initiatives, and project-level claims.

ISO 14064-3: Validation and Verification specifies principles and requirements for verifying and validating GHG statements. It provides the framework that verification bodies use to assess whether GHG inventories and project claims are accurate, complete, and consistent. This part is used by accredited verification bodies worldwide.

Together, the three parts create a complete system: measure (Part 1 or 2), verify (Part 3), and report with credibility.

The standard is changing. In September 2025 ISO and the GHG Protocol announced a partnership to harmonize their standards, and they are co-developing a consolidated, co-branded corporate standard that merges ISO 14064-1 with the GHG Protocol's Corporate Standard, Scope 2 Guidance, and Scope 3 Standard. Public consultation is planned for the second quarter of 2027 and publication for the fourth quarter of 2028. A revision of ISO 14064-2 is also under way.

Who Uses It

• Organizations requiring third-party verified emissions data — for regulatory compliance, carbon trading, or stakeholder credibility
• Companies subject to CSRD — where external assurance of emissions data is mandatory
• Carbon market participants — project developers and buyers requiring ISO 14064-2 for project-level accounting
• Government agencies implementing GHG reporting programs
• Verification bodies — accredited entities use ISO 14064-3 as their verification standard

Key Requirements

ISO 14064-1 (Organization Level):

• Define organizational and operational boundaries
• Identify and categorize GHG sources and sinks
• Quantify GHG emissions and removals using recognized methodologies and emission factors
• Develop a GHG management plan including base year, recalculation policy, and uncertainty assessment
• Prepare a GHG report meeting specified content requirements
• Consider verification as part of the reporting process

ISO 14064-2 (Project Level):

• Define the project baseline scenario
• Monitor and quantify GHG emission reductions or removal enhancements
• Assess and manage uncertainty
• Report project-level GHG performance
• Subject claims to validation and verification

ISO 14064-3 (Verification):

• Plan and execute verification engagement following specified procedures
• Assess materiality and risk
• Evaluate evidence using sampling and testing techniques
• Provide a verification opinion (reasonable or limited level of assurance)

How to Implement

Phase 1: Boundary Definition (2-4 weeks) Define organizational boundary (equity share or control approach). Define operational boundary (which emission categories to include). Align with GHG Protocol scopes if dual-reporting.

Phase 2: Inventory Development (2-4 months) Identify all GHG sources and sinks. Collect activity data. Apply emission factors. Calculate emissions. Assess uncertainty. Document methodology and data sources.

Phase 3: Quality Management (1-2 months) Establish data quality management procedures. Implement internal review processes. Address data gaps and quality issues. Prepare for external verification.

Phase 4: Verification (1-3 months) Select an accredited verification body. Undergo verification process (planning, document review, site visits, evidence testing). Address any findings. Receive verification statement.

Relationship to Other Frameworks

GHG Protocol: ISO 14064-1 and GHG Protocol Corporate Standard are largely compatible. Many organizations use GHG Protocol methodology and have their inventory verified under ISO 14064-3. Key differences exist in categorization (ISO uses indirect emission categories rather than the Scope 1/2/3 terminology, though the 2018 revision improved alignment). The two are set to merge into one consolidated corporate standard, planned for publication in late 2028.

SBTi: The SBTi's near-term criteria (version 5.3.1, April 2026) require companies to follow the GHG Protocol Corporate Standard, Scope 2 Guidance, and Scope 3 Standard, and the SBTi does not accept GHG accounting that is not shown to adhere to the GHG Protocol. An inventory prepared under ISO 14064-1 therefore also has to meet GHG Protocol requirements.

CSRD/ESRS: The CSRD requires limited assurance of the sustainability statement, including GHG emissions reported under ESRS E1. ISO 14064-3 provides a recognized verification framework.

Carbon markets: ISO 14064-2 and 14064-3 are used across voluntary and compliance carbon markets for project-level accounting and verification.

Why It Matters

ISO 14064 matters because it provides the verification framework that makes GHG data credible. As sustainability reporting moves from voluntary to mandatory — and from self-reported to externally assured — the importance of standardized verification methodologies increases dramatically.

The GHG Protocol tells you how to measure. ISO 14064-3 tells verifiers how to check. As the CSRD, California's SB 253, and jurisdictions adopting ISSB standards such as Australia, Japan, and Singapore require assurance of emissions data, ISO 14064 becomes the quality assurance layer that ensures climate claims can withstand scrutiny.

For organizations in carbon markets — whether selling credits from reduction projects or purchasing offsets — ISO 14064-2 provides the project-level accounting rigor needed for credible claims. In a market plagued by quality concerns, ISO 14064 verification provides essential credibility.