GHG Protocol and ISO Alignment: What Changes and When

Corporate carbon accounting has long been built on two parallel foundations. Most companies calculate their emissions using the GHG Protocol, while ISO 14064-1 provides the organisation-level framework for quantifying and reporting emissions that's widely used alongside GHG Protocol in corporate accounting and assurance. The two overlap heavily, but they are not identical, and companies operating across multiple markets have often had to reconcile both.

That is set to change. On 29 July 2026, the GHG Protocol announced that it and the International Organization for Standardization will combine their corporate carbon accounting standards into a single, harmonised global standard.

What was announced

The announcement covered three connected updates.

• The consolidation itself. GHG Protocol and ISO will publish a single co-branded corporate standard rather than maintaining separate frameworks. The work builds on a strategic partnership the two organisations established the previous year, and is a milestone set out in the COP30 Action Agenda on harmonising global greenhouse gas accounting.
• Results from the Scope 2 public consultation. The consultation attracted close to 1,100 responses from 56 countries.
• Preliminary feedback on Actions and Market Instruments. This came from a Request for Information on the workstream, which will now be developed as part of the consolidated standard rather than as a separate output.

What is being consolidated

Five existing standards and workstreams are being brought together.

It is worth noting what is excluded: The Land Sector and Removals Standard and Guidance, published separately in 2026, is not part of this particular corporate-standard consolidation.

How the new standard will be structured

The consolidated standard is expected to be published in two parts, supported by additional implementation guidance.

• Part 1 is expected to cover general requirements and the physical greenhouse gas inventory, meaning the Scope 1, Scope 2 and Scope 3 emissions that companies report today. 
• Part 2 is expected to cover Actions and Market Instruments.

GHG Protocol currently refers to the planned output as the Corporate Accounting and Reporting Standard, Version 3.0. The title is provisional and will be finalised with ISO.

Actions and Market Instruments explained

Actions and Market Instruments is the least familiar part of the package and the part most likely to change what a corporate climate report looks like, so it is worth setting out before turning to the rest of the proposals.

An action is any intervention that leads to a change in emissions or removals, such as a project, an investment, or the production or purchase of a product. Examples include electricity attribute certificates and other contractual instruments used to make claims about the attributes associated with energy or other products.

The workstream proposes a multi-statement reporting structure, which would allow companies to report three distinct things separately rather than folding them into a single figure:

1. Physical emissions. Emissions from the company's own operations and value chain, which is broadly what inventories capture today.
2. Market-based emissions. Emissions associated with contractual instruments such as commodity certificates and mitigation-related agreements.
3. Greenhouse gas impact statement. The estimated emissions impact of a company's actions and investment decisions, with consequential accounting methods among the approaches under consideration.

Preliminary feedback from the Request for Information indicated significant support for this approach, including the multi-statement structure itself, the market-based inventory concept, and a separate statement for the impact of actions.

For companies wanting to move early, GHG Protocol has offered interim direction: report physical inventory emissions, market-based emissions and the impacts of climate actions separately and transparently, without netting between the categories, while the detailed requirements are developed.

What could change in practice

The technical requirements have not been decided, and the consultation draft has not yet been published. The Standard Development Plan does, however, identify several areas where changes are under active consideration.

• Organisational boundaries. Descriptions of organisational boundaries may be updated to align more closely with financial accounting principles. The three existing consolidation methods may be narrowed or ranked, and clarifications are planned for control, leases, joint ventures, minority interests, base-year recalculations and mid-year structural changes.
• Scope 2 and renewable energy claims. Measurement principles may be refined to add rigour to the accounting treatment of renewable energy procurement arrangements and contractual instruments, including energy attribute certificates.
• Scope 3 completeness. One proposal would require disclosure of all Scope 3 categories, subject to a minimum threshold, rather than allowing companies to report only the categories they consider material.
• Financial institutions. Guidance on Scope 3 category 15, covering investments, may be updated to reshape which types of emissions financial institutions are required to report.

Taken together, these would represent a meaningful shift rather than a tidying exercise, particularly the proposals around Scope 3 completeness and the accounting treatment of energy attribute certificates.

The timeline is subject to change as the revision process continues.

What it means for regulators and reporting frameworks

The consolidated standard will not take effect automatically in regulated reporting.

Current GHG Protocol standards are referenced extensively in the IFRS Sustainability Disclosure Standards and in the European Sustainability Reporting Standards. The International Sustainability Standards Board and the European Commission would each need to consider separately, and consult on, whether and when to embed the revised standard in their own requirements.

That means companies reporting under the Corporate Sustainability Reporting Directive (CSRD) and European Sustainability Reporting Standards, or under frameworks incorporating IFRS S2, should expect a lag between publication in late 2028 and any change to what those frameworks require. Target-setting and disclosure programmes will likewise make their own decisions about which elements they adopt.

What companies should do now

The practical answer for most organisations is to keep going and stay informed.

1. Continue reporting under the current standards. The existing Corporate Standard, Scope 2 Guidance and Scope 3 Standard remain the current GHG Protocol frameworks while the consolidated version is developed.
2. Monitor the development process. The areas under review, particularly Scope 3 completeness and energy attribute certificates, are the ones most likely to affect existing inventories.
3. Strengthen data quality where the proposals point. Companies that currently report only their material Scope 3 categories would face more work if a completeness requirement is introduced, so improving coverage now reduces the size of that step later.
4. Review documentation on renewable energy claims. If contractual instruments form a significant part of the Scope 2 position, the underlying evidence for those claims is worth checking against the direction of travel.
5. Consider the multi-statement approach for internal reporting. Separating physical emissions, market-based emissions and the impact of actions is useful discipline regardless of when it becomes a requirement.
6. Watch for signals from regulators. Updates from the ISSB, the European Commission and other regulators will determine when the consolidated standard actually affects compliance obligations.

How Zevero can help

Zevero supports companies through methodology changes by keeping the underlying data structured and traceable.

• Standards-aligned accounting. Zevero calculates Scope 1, Scope 2 and Scope 3 emissions in line with the GHG Protocol and ISO 14064-1, which are the two frameworks being consolidated.
• A transparent calculation trail. Every figure can be traced to its source data and the emission factor applied, which is what makes recalculation and base-year restatement manageable when requirements change.
• Scope 3 breadth. Where companies need to extend coverage across more categories, Zevero supports the move from spend-based estimates to activity-based and supplier-specific data.

Get in touch with us to discuss how the consolidated standard could affect your reporting.