What Is ISO 14064-1 GHG Verification? Complete Guide

What Is ISO 14064-1?

ISO 14064-1 is the first part of the ISO 14064 series and establishes the principles and requirements for the design, development, management, and reporting of an organisation-level greenhouse gas (GHG) inventory. Published by the International Organization for Standardization (ISO), it provides a standardised framework that enables organisations to quantify their GHG emissions and removals in a consistent, transparent, and comparable manner.

The ISO 14064 series consists of three parts that work together to form a comprehensive GHG management and verification framework:

• ISO 14064-1: Organisation-level quantification and reporting of GHG emissions and removals
• ISO 14064-2: Project-level quantification, monitoring, and reporting of GHG emission reductions or removal enhancements
• ISO 14064-3: Specification with guidance for the verification and validation of GHG statements

ISO 14064-1 is designed to be applicable to any organisation regardless of size, type, or sector. It is sector-neutral and can be applied by manufacturing companies, financial institutions, government bodies, service providers, and any other entity seeking to understand and report its carbon footprint. The standard does not prescribe specific emission reduction targets; rather, it establishes how an organisation should measure and report its current GHG position.

Historical Context

The original ISO 14064-1 was published in 2006 as part of ISO's response to the growing need for standardised GHG accounting. It was developed alongside the GHG Protocol Corporate Standard (first published in 2001 by WRI and WBCSD) and drew on many of the same foundational principles. The standard underwent a significant revision in 2018, which modernised its approach to indirect emissions and aligned it more closely with evolving climate disclosure requirements.

ISO 14064-1 sits within the broader ISO 14000 family of environmental management standards, which includes ISO 14001 (Environmental Management Systems), ISO 14040/14044 (Life Cycle Assessment), and ISO 14067 (Carbon Footprint of Products). This family provides a comprehensive toolkit for organisations pursuing environmental sustainability objectives.

The 2018 Revision: Key Changes

ISO 14064-1:2018 represented a substantial update from the 2006 edition. The revision addressed the evolving landscape of GHG reporting and brought the standard into closer alignment with contemporary best practices. Understanding these changes is essential for organisations preparing for verification.

Six Emission Categories

The most significant structural change was the introduction of six emission and removal categories, replacing the previous alignment with the GHG Protocol's three-scope model. The six categories are:

1. Category 1 — Direct GHG emissions and removals: Emissions from sources owned or controlled by the organisation (equivalent to Scope 1)
2. Category 2 — Indirect GHG emissions from imported energy: Emissions from the generation of imported electricity, heat, or steam (equivalent to Scope 2)
3. Category 3 — Indirect GHG emissions from transportation: Emissions from transportation of materials, products, waste, and employees
4. Category 4 — Indirect GHG emissions from products used by the organisation: Emissions from purchased goods, capital goods, and upstream activities
5. Category 5 — Indirect GHG emissions associated with the use of products from the organisation: Emissions from the use and end-of-life treatment of sold products
6. Category 6 — Indirect GHG emissions from other sources: Any other indirect emissions not covered in categories 3-5

In practice, most organisations and verifiers continue to use the widely recognised Scope 1, 2, and 3 terminology alongside the ISO categories. The mapping is straightforward: Category 1 = Scope 1, Category 2 = Scope 2, and Categories 3-6 collectively = Scope 3.

Enhanced Indirect Emissions Requirements

The 2018 revision significantly strengthened requirements for reporting indirect emissions (Categories 3-6 / Scope 3). Organisations must now assess the significance of all indirect emission categories and provide documented justification for any categories excluded from the inventory. This shift reflects the reality that for many organisations—particularly in the services, finance, and technology sectors—indirect emissions represent 80-95% of the total carbon footprint.

Other Key Changes

• Biogenic CO2 reporting: Separate reporting of biogenic carbon dioxide emissions and removals is now required
• Avoided emissions: Clearer guidance on the treatment of avoided emissions, distinguishing them from actual emission reductions
• Uncertainty assessment: Strengthened requirements for assessing and reporting uncertainty in quantification
• Base year recalculation: More explicit requirements for when and how to recalculate the base year inventory
• Consolidation approaches: Clarified requirements for equity share and control (financial and operational) consolidation approaches

Emission Categories: Direct, Energy Indirect, and Other Indirect

Understanding how emissions are categorised is fundamental to building an accurate GHG inventory and preparing for verification. Each category has distinct data requirements, quantification methodologies, and evidence expectations.

Category 1 / Scope 1: Direct Emissions

Direct GHG emissions occur from sources that are owned or controlled by the reporting organisation. These are typically the most straightforward to quantify because the organisation has direct access to activity data.

• Stationary combustion: Fuel burned in boilers, furnaces, turbines, heaters, and generators
• Mobile combustion: Fuel burned in company-owned or controlled vehicles, aircraft, and ships
• Process emissions: GHGs released from industrial processes such as cement production, aluminium smelting, or chemical manufacturing
• Fugitive emissions: Unintentional releases from refrigerant leaks, natural gas distribution, coal mining, and wastewater treatment

Category 2 / Scope 2: Energy Indirect Emissions

Energy indirect emissions come from the generation of purchased or acquired electricity, heating, cooling, and steam consumed by the organisation. ISO 14064-1:2018 requires organisations to report these using both the location-based and market-based methods where applicable.

• Location-based method: Uses average grid emission factors for the geographic location where the energy is consumed
• Market-based method: Uses emission factors from specific contractual instruments such as Renewable Energy Certificates (RECs), Guarantees of Origin (GOs), or power purchase agreements (PPAs)

Categories 3-6 / Scope 3: Other Indirect Emissions

Other indirect emissions are a consequence of the organisation's activities but occur from sources not owned or controlled by the organisation. The 2018 revision requires a documented assessment of significance for each category. Common sources include:

• Purchased goods and services: Cradle-to-gate emissions from procured materials and services
• Capital goods: Emissions from the manufacture of purchased capital equipment
• Fuel- and energy-related activities: Upstream emissions not included in Scope 1 or 2 (e.g., well-to-tank emissions)
• Upstream and downstream transportation: Movement of goods, materials, and waste
• Waste generated in operations: Third-party treatment and disposal of waste
• Business travel: Employee travel in non-company-owned vehicles
• Employee commuting: Travel between home and workplace
• Use of sold products: Emissions from customer use of the organisation's products
• End-of-life treatment of sold products: Disposal and recycling of sold products

Quantification Principles

ISO 14064-1 establishes five fundamental principles that underpin the GHG inventory process. Verifiers assess compliance with these principles throughout the verification engagement.

The Five Principles

Quantification Approaches

ISO 14064-1 recognises several approaches for quantifying GHG emissions:

• Calculation-based (emission factors): Activity data multiplied by emission factors. This is the most common approach, using factors from recognised databases such as IPCC, DEFRA, EPA, or national inventories
• Direct measurement: Continuous emissions monitoring systems (CEMS) or periodic stack testing. Required for certain large-point-source emitters under regulatory schemes
• Mass balance: Quantification based on input/output mass flows of carbon-containing materials. Common in chemical and process industries
• Modelling: Estimation using process-specific models, typically for fugitive emissions or complex processes

The choice of quantification approach depends on the emission source, data availability, regulatory requirements, and the desired level of accuracy. Verifiers will assess whether the chosen approach is appropriate for each source and whether emission factors are current and relevant.

Reporting Requirements

ISO 14064-1 specifies detailed requirements for the GHG inventory report (also called the GHG assertion or GHG statement). The report forms the basis of the verification engagement. A compliant GHG report must include:

Mandatory Report Content

• Reporting organisation: Legal name, description, and relevant contextual information
• Responsible party: Person or team accountable for the GHG inventory
• Reporting period: Start and end dates of the inventory period
• Organisational boundary: Consolidation approach (equity share or control) and entities included
• Operational boundary: Emission categories included and excluded, with justification for exclusions
• Quantification methodologies: Methods, emission factors, and data sources used for each category
• GHG emissions and removals: Quantified results by category, reported in tonnes of CO2 equivalent (tCO2e)
• Base year: Base year inventory and recalculation policy
• Uncertainty assessment: Qualitative or quantitative assessment of uncertainty
• Biogenic CO2: Separately reported biogenic carbon dioxide emissions and removals

GHG Types

ISO 14064-1 requires reporting of the seven greenhouse gases covered by the Kyoto Protocol and its amendments:

• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• Hydrofluorocarbons (HFCs)
• Perfluorocarbons (PFCs)
• Sulphur hexafluoride (SF6)
• Nitrogen trifluoride (NF3)

All GHG emissions are converted to carbon dioxide equivalent (CO2e) using Global Warming Potentials (GWPs) from the IPCC. The GWP time horizon (typically 100 years—GWP100) should be specified and consistently applied.

Verification Under ISO 14064-3

While ISO 14064-1 defines what to measure and report, ISO 14064-3 defines how the reported information is independently verified. Verification provides stakeholders—investors, regulators, customers, and the public—with confidence that the GHG data is reliable.

What Verification Involves

A verification engagement under ISO 14064-3 typically follows these stages:

1. Pre-engagement: Define scope, objectives, materiality threshold, and level of assurance
2. Planning: Develop verification plan, assess risks, design sampling approach
3. Execution: Review documentation, test data, conduct site visits (if applicable), interview responsible personnel
4. Evaluation: Assess findings against materiality, aggregate errors, form opinion
5. Reporting: Issue verification statement and management report

Levels of Assurance

ISO 14064-3 defines two levels of assurance:

Materiality

Materiality is a critical concept in GHG verification. It is the threshold at which an error, omission, or misstatement could influence the decisions of the intended user. Materiality is typically set as a percentage of total reported emissions—commonly 5% for reasonable assurance and 5-10% for limited assurance. The materiality threshold is agreed upon at the start of the engagement between the verifier and the responsible party.

ISO 14064-1 vs GHG Protocol

ISO 14064-1 and the GHG Protocol Corporate Standard are the two most widely used frameworks for organisational GHG accounting. While they share common roots and are broadly compatible, there are notable differences.

Many organisations use the GHG Protocol as their primary reporting framework while seeking verification against ISO 14064-1 requirements. The two are sufficiently compatible that a well-prepared GHG Protocol inventory can typically be verified against ISO 14064-1 with minimal additional work. Verifiers are familiar with both frameworks and can advise on any reconciliation needed.

Benefits of Verification

Independent third-party verification of a GHG inventory delivers value across multiple dimensions—from regulatory compliance to competitive advantage.

Stakeholder Confidence

• Investor assurance: ESG-focused investors increasingly require verified emissions data. Verified inventories support TCFD, ISSB, and CSRD disclosures
• Customer trust: Supply chain partners and B2B customers use verified data to calculate their own Scope 3 emissions
• Regulatory compliance: Many regulatory schemes require or strongly prefer verified data
• Public credibility: Verified claims are materially different from self-reported data in the eyes of media, NGOs, and the public

Internal Benefits

• Data quality improvement: The verification process identifies errors, gaps, and methodological weaknesses that strengthen future inventories
• Process maturity: Preparing for verification forces organisations to formalise data collection, internal controls, and documentation practices
• Baseline integrity: Verified base year data provides a reliable foundation for setting and tracking science-based targets
• Risk identification: Verification often uncovers operational risks related to energy use, waste, and supply chain emissions

Commercial Advantages

• CDP scoring: Verified data can improve CDP scores, which are increasingly used in procurement and investment decisions
• Green finance: Green bonds, sustainability-linked loans, and climate-focused funds often require verified emissions data
• Supply chain access: Major buyers (e.g., Walmart, Apple, Microsoft) increasingly require suppliers to provide verified Scope 1 and 2 data
• Carbon markets: Participation in emissions trading schemes and carbon offset markets typically requires verified data

Regulatory Recognition

ISO 14064-1 verification is recognised or required by a growing number of regulatory and voluntary reporting frameworks worldwide.

Getting Started with ISO 14064-1 Verification

Organisations considering ISO 14064-1 verification for the first time should follow a structured approach to ensure a smooth and efficient process.

Step 1: Prepare Your GHG Inventory

Ensure your inventory is complete, accurate, and well-documented. At minimum, you need defined organisational and operational boundaries, quantified Scope 1 and 2 emissions with documented methodologies, an assessment of Scope 3 categories with justification for any exclusions, and supporting activity data with clear source documentation.

Step 2: Select a Verification Body

Choose a verification body that is accredited under ISO 14065 by a recognised accreditation body (e.g., UKAS, ANAB, JAS-ANZ). Accreditation ensures the verifier has demonstrated competence and operates an impartial quality management system. Check whether your reporting scheme specifies particular accreditation requirements.

Step 3: Agree on Scope and Materiality

Work with the verifier to define the engagement scope—which emission categories are covered, the materiality threshold, the level of assurance (reasonable or limited), and any scheme-specific requirements. This is typically formalised in an engagement agreement or terms of reference.

Step 4: Compile Your Evidence Pack

Prepare documentation including raw activity data (invoices, meter readings, fuel receipts), emission factor sources, calculation spreadsheets or software outputs, internal review records, and any changes from the prior year. A well-organised evidence pack significantly reduces verification time and cost.

Step 5: Undergo Verification

The verifier will conduct document review, data testing, and potentially site visits before issuing the verification statement. Address any findings promptly to avoid delays in receiving your statement.

Organisations that invest in data management systems and internal controls before their first verification typically complete the process 40% faster and with fewer corrective action requests than those that compile data only when the verifier arrives.

Frequently Asked Questions

What is ISO 14064-1 verification?

ISO 14064-1 verification is an independent third-party assessment of an organisation's greenhouse gas (GHG) inventory against the requirements of ISO 14064-1. A qualified verifier examines the GHG assertion—including Scope 1, 2, and 3 emissions data, quantification methodologies, and supporting evidence—to provide a verification statement expressing either reasonable or limited assurance that the inventory is materially correct.

What changed in the ISO 14064-1:2018 revision?

The 2018 revision introduced six GHG emission categories replacing the three-scope model, although Scope 1/2/3 terminology remains widely used alongside. It added requirements for indirect emissions beyond energy (equivalent to Scope 3), strengthened quantification principles, introduced biogenic CO2 reporting, and aligned with GHG Protocol Corporate Standard more closely.

How does ISO 14064-1 differ from the GHG Protocol?

ISO 14064-1 is an ISO standard with formal verification requirements under ISO 14064-3, while the GHG Protocol is a voluntary reporting framework. ISO 14064-1:2018 uses six emission categories compared to the GHG Protocol's three scopes. Both are widely recognised and largely compatible, with many organisations using GHG Protocol for reporting and ISO 14064-1 as the basis for third-party verification.

Is ISO 14064-1 verification mandatory?

ISO 14064-1 verification is voluntary in most jurisdictions. However, it is effectively mandatory for organisations participating in the EU Emissions Trading System (EU ETS), California's Cap-and-Trade programme, CBAM reporting, and CDP disclosure at leadership level. Many ESG frameworks and supply chain requirements also increasingly expect third-party verified GHG data.

How long does ISO 14064-1 verification take?

A typical ISO 14064-1 verification engagement takes 4-8 weeks from kick-off to issuance of the verification statement. Timelines depend on organisational complexity, number of sites, data quality, and whether site visits are required. Organisations with well-prepared GHG inventories and robust data management can complete verification in as little as 3-4 weeks.