GHG Protocol and ISO Join Forces to Standardise Carbon Accounting

GHG Protocol announces partnership with ISO to merge corporate carbon standards

The GHG Protocol has entered a formal partnership with ISO to merge their flagship carbon accounting standards into a single set of co-branded international frameworks. The collaboration brings together the ISO 1406X family and the GHG Protocol’s Corporate Accounting and Reporting, Scope 2, and Scope 3 standards. Announced in September 2025, the agreement aims to eliminate duplication between the two most widely used emissions measurement systems.

This partnership sits alongside a broader technical overhaul of the GHG Protocol’s existing standards. The organisation has opened public consultations on Scope 2 guidance and consequential accounting methods, scheduled a new Land Sector and Removals Standard for January 2026, and committed to releasing a revised Corporate Standard in mid-2026. Together, these developments represent the most significant restructure of corporate carbon accounting frameworks since the original GHG Protocol standards were published more than two decades ago.

For UK businesses, the implications are practical. Most carbon footprint reports, net zero strategies, and PPN 06/21 submissions rely on GHG Protocol methods. Changes to these underlying standards will affect how emissions are calculated, what data you need to collect, and how your disclosures compare with competitors and supply chain partners. Furthermore, the shift toward internationally recognised ISO standards may influence future UK regulatory requirements and public procurement criteria.

The timeline for implementation remains uncertain. Draft standards are expected in 2026, with final versions anticipated in 2027. However, the scale of the revision suggests a phased rollout, meaning some businesses may operate under transitional arrangements for several years. Consequently, planning for these changes now will help avoid last-minute compliance scrambles later.

Partnership creates unified international carbon accounting framework

The September 2025 announcement confirmed that ISO and the GHG Protocol will co-develop new measurement and reporting standards. The GHG Protocol described the move as “a new era” in carbon accounting. Both organisations will harmonise their existing portfolios and jointly develop future standards, including a unified product carbon footprint methodology.

The partnership addresses a long-standing problem in corporate sustainability reporting. Companies currently navigate multiple overlapping frameworks, each with slightly different calculation methods, boundary definitions, and disclosure requirements. ISO standards carry formal international recognition and are often referenced in trade agreements and regulatory frameworks. Meanwhile, the GHG Protocol has become the de facto global standard for corporate emissions reporting, used by thousands of businesses and embedded in disclosure platforms such as CDP.

Merging these two systems should reduce duplication and improve comparability. If a supplier in Germany, a customer in Japan, and a UK manufacturer all apply the same standard, supply chain emissions data becomes more reliable. Similarly, investors and regulators can compare disclosures more easily when companies follow a consistent methodology. The collaboration also creates a clearer pathway for future technical updates, with both organisations committing to joint development rather than parallel revisions.

However, the announcement provides limited detail on how the merged standards will work in practice. Questions remain about which elements of each framework will take precedence, how existing users should transition, and whether the new standards will require different data inputs or calculation tools. These details will emerge through public consultations planned for 2026.

Scope 2 and consequential accounting consultations now open for feedback

On 20 October 2025, the GHG Protocol opened two public consultations. The first addresses updates to the Scope 2 Guidance, originally published in 2015. The second covers consequential accounting methods for estimating avoided emissions from electricity-sector actions. Both consultations were initially set to close in late 2025 but were extended to 31 January 2026 to allow more time for industry feedback.

Scope 2 emissions cover purchased electricity, heat, steam, and cooling. The current guidance allows businesses to report using either a location-based method, which applies average grid emissions factors, or a market-based method, which reflects contractual instruments such as renewable energy certificates. The proposed updates may refine how these methods are applied, particularly for businesses with complex energy procurement arrangements or operations across multiple grids.

Consequential accounting represents a more technical shift. Instead of calculating emissions based on what a business has directly consumed or purchased, consequential methods estimate the broader impact of specific decisions on total system emissions. For example, a company switching to renewable energy might claim credit for the emissions avoided by displacing fossil fuel generation on the grid. This approach is more complex than traditional attributional accounting and requires robust data on grid dynamics, generation dispatch, and marginal emissions factors.

The consultation period reflects the GHG Protocol’s intention to gather input from auditors, corporate reporters, and technical experts before finalising the guidance. UK businesses that report Scope 2 emissions or participate in renewable energy markets should review the draft proposals. Changes to Scope 2 methods could affect how electricity purchases are reflected in carbon disclosures, which in turn may influence procurement decisions and renewable energy strategies.

Land Sector and Removals Standard launches in January 2026

The GHG Protocol has confirmed it will publish its first Land Sector and Removals Standard on 30 January 2026. The standard will take effect from 1 January 2027, giving businesses a 12-month transition window. This new framework addresses emissions and removals associated with land use, forestry, agriculture, and nature-based carbon sequestration projects.

Currently, businesses struggle to account for land-sector emissions consistently. Agricultural supply chains, forestry operations, and carbon offset projects often rely on fragmented methodologies with limited comparability. The new standard aims to provide a unified approach for measuring emissions from land-use change, quantifying carbon removals in forests and soils, and reporting on nature-based carbon projects.

For UK businesses with agricultural supply chains or land-based carbon removal projects, this standard will become the reference framework. It will clarify how to account for Scope 3 emissions from agricultural inputs, how to report carbon removals from afforestation or soil carbon projects, and how to integrate nature-based solutions into corporate net zero strategies. Moreover, the standard may influence how businesses assess carbon credits from forestry or regenerative agriculture projects.

The January 2026 release date suggests the standard is nearing completion. However, practical adoption will depend on how quickly businesses, auditors, and verification bodies develop the tools and expertise needed to apply the new methods. As a result, early movers who engage with the standard during 2026 may gain an advantage in supply chain transparency and carbon project credibility.

Revised Corporate Standard draft expected mid-2026

The GHG Protocol has committed to releasing a complete draft of the revised Corporate Standard in mid-2026. This update will overhaul the foundational framework that businesses use to measure and report their total emissions footprint. The current Corporate Standard, published in 2001 and updated in 2004, has remained largely unchanged for two decades despite significant shifts in reporting practices, disclosure regulations, and carbon markets.

The revision will likely address issues that have emerged as corporate carbon reporting has become more widespread. Boundary-setting rules, which determine which entities and operations a business must include in its inventory, may be clarified. Accounting for joint ventures, franchises, and complex corporate structures has proven difficult under the existing guidance. Additionally, the revised standard may provide clearer direction on how to integrate carbon credits, removals, and offsetting into corporate emissions disclosures.

Progress updates indicate the revision will also consider how the Corporate Standard interacts with the Scope 2 and Scope 3 guidance. Changes to these supplementary standards could necessitate corresponding updates to the core framework. Consequently, the mid-2026 draft will likely reflect a coordinated package of revisions rather than isolated updates.

For businesses already reporting under the GHG Protocol, the revision presents both an opportunity and a risk. Clearer guidance could reduce ambiguity and improve confidence in reported figures. However, methodological changes may disrupt trend data, making year-on-year comparisons more difficult. Businesses should monitor the consultation process closely and prepare for potential adjustments to data collection, calculation tools, and disclosure formats.

Scope 3 Standard review addresses data quality and boundary issues

The GHG Protocol has released a progress update on potential revisions to the Scope 3 Standard. External advisory summaries suggest this work may include changes to data quality requirements, boundary-setting rules, and the treatment of investments. Scope 3 emissions, which cover indirect emissions from a business’s value chain, are often the largest component of a corporate carbon footprint but also the most difficult to measure accurately.

Data quality remains a persistent challenge. Many businesses rely on estimates, industry averages, or supplier-provided data that varies in reliability. The revised standard may introduce clearer guidance on when businesses can use secondary data, how to improve data quality over time, and what level of uncertainty is acceptable in different reporting contexts. Similarly, boundary-setting rules may be updated to clarify which categories of emissions must be included and which can be excluded.

Investments represent a particularly complex area. Financial institutions and businesses with large investment portfolios must account for emissions associated with their holdings. The current Scope 3 Standard provides limited guidance on how to allocate emissions from financed activities, joint ventures, or equity stakes. Revisions may introduce more detailed methodologies, particularly as regulators in the UK and EU impose stricter disclosure requirements on financial institutions.

The Scope 3 revision is proceeding in parallel with the Corporate Standard update and the ISO partnership. Businesses should assume that changes to Scope 3 methods will align with the broader harmonisation effort. Therefore, the revised Scope 3 Standard will likely form part of the integrated framework announced in the ISO partnership.

Changes to global carbon accounting standards carry practical consequences

• The GHG Protocol and ISO announced a partnership in September 2025 to merge their carbon accounting standards into a unified set of co-branded international frameworks.
• Public consultations on Scope 2 guidance and consequential accounting methods opened on 20 October 2025 and were extended to close on 31 January 2026.
• The first Land Sector and Removals Standard will be published on 30 January 2026 and takes effect from 1 January 2027.
• A complete draft of the revised Corporate Standard is scheduled for release in mid-2026, with final versions expected in 2027.
• Revisions to the Scope 3 Standard are underway and may address data quality, boundary-setting, and the treatment of investments.
• The changes aim to reduce fragmentation in emissions accounting and improve comparability across jurisdictions and reporting frameworks.
• Phased implementation suggests businesses may operate under transitional arrangements for several years before the new framework is fully adopted.

Why UK businesses should track these developments closely

These revisions will affect how you measure, report, and verify your carbon footprint. Most UK businesses use GHG Protocol methods for carbon reporting, whether to meet PPN 06/21 requirements, disclose through CDP, or support net zero commitments. Changes to underlying calculation methods will alter your reported emissions figures, potentially disrupting trend data and requiring updates to carbon reduction targets.

Procurement teams will also feel the impact. If your supply chain partners adopt revised standards at different speeds, comparing supplier emissions data will become more difficult. Similarly, if your customers or investors expect disclosures aligned with the new ISO-GHG Protocol framework, you may need to adjust reporting formats before the standards are mandatory. Early engagement with the consultation process gives you a chance to influence the final methodologies and prepare for implementation.

Regulatory alignment is another consideration. The UK government has signalled its intention to introduce mandatory climate-related disclosures for large businesses and may eventually extend these requirements to smaller firms. If UK regulations reference ISO standards or the revised GHG Protocol, compliance will depend on adopting the new methods. Public sector suppliers should pay particular attention, as central government procurement increasingly requires carbon reporting that aligns with recognised international standards.

Businesses already using carbon management software or external consultants should ask how their tools will adapt to the revised standards. Calculation engines, data collection templates, and verification procedures will all need updating. Waiting until the final standards are published in 2027 may leave insufficient time to make these adjustments before the next reporting cycle. In addition, businesses with complex supply chains or international operations should consider how the harmonisation of ISO and GHG Protocol standards will affect multi-jurisdictional reporting.

Training and internal capacity will matter too. Finance teams, sustainability managers, and procurement professionals will need to understand the new methods, particularly if changes to Scope 2 or Scope 3 guidance alter how emissions are allocated across business units. SBS Academy training on carbon accounting fundamentals can help teams prepare for these technical shifts before they become mandatory.

What the revised standards mean for carbon reporting and net zero planning

The move toward a unified ISO-GHG Protocol framework will likely improve the credibility of corporate carbon disclosures. Investors, regulators, and auditors have grown increasingly sceptical of carbon reporting that lacks rigorous methodologies or third-party verification. A single set of internationally recognised standards makes it easier to audit emissions data, compare corporate performance, and identify businesses that are genuinely reducing emissions rather than relying on creative accounting.

However, the transition period will create uncertainty. Businesses that report annually will face decisions about when to adopt the new methods. Switching mid-cycle will disrupt trend data, but waiting too long may leave you out of step with competitors or regulatory expectations. Some businesses may choose to dual-report during the transition, presenting figures under both old and new methods to maintain comparability.

The revised standards may also affect carbon reduction strategies. If Scope 2 methods change how renewable energy purchases are reflected in disclosures, businesses may reassess their energy procurement strategies. Similarly, if Scope 3 guidance tightens data quality requirements, businesses may need to invest in better supply chain engagement or supplier audits. Our net zero program for carbon reporting compliance helps businesses navigate these technical updates while maintaining progress toward reduction targets.

The Land Sector and Removals Standard will open new opportunities for businesses exploring nature-based carbon solutions. Clearer accounting rules for forestry projects, soil carbon sequestration, and regenerative agriculture could make these options more attractive as part of a net zero strategy. Nevertheless, businesses should remain cautious about relying too heavily on removals or offsets without accompanying emissions reductions in their core operations.

Ultimately, the revised standards will reward businesses that have invested in robust data collection and transparent reporting. Companies with strong governance, reliable supply chain data, and clear methodologies will find it easier to adapt. Those that have relied on rough estimates or inconsistent methods may face more significant adjustments. Starting the preparation process now, rather than waiting for final publication in 2027, will reduce disruption and maintain confidence in your carbon disclosures.

Where to find further guidance on the GHG Protocol revisions

The GHG Protocol website provides official updates on the revision process, including consultation documents, timelines, and technical drafts. Businesses interested in contributing to the consultations should review the Scope 2 and consequential accounting proposals before the 31 January 2026 deadline. The site also hosts the existing Corporate, Scope 2, and Scope 3 standards, which remain the applicable frameworks until revised versions are published.

For information on ISO carbon accounting standards, visit the ISO Technical Committee 207 page, which oversees the ISO 1406X family of greenhouse gas standards. This committee coordinates the development of international environmental management standards, including those related to carbon footprinting, life cycle assessment, and emissions verification.

UK businesses looking for regulatory context should consult the Department for Energy Security and Net Zero, which sets domestic climate policy and may eventually reference the revised GHG Protocol or ISO standards in UK disclosure requirements. The department’s guidance on carbon reporting and net zero strategy provides a useful complement to the technical standards.

For practical support on implementing the revised standards once they are published, SBS compliance services for carbon reporting can help you update your calculation methods, train internal teams, and maintain comparability with previous disclosures. Preparing now will ensure you are ready to adopt the new framework as soon as it becomes the recognised standard for corporate carbon accounting.