Insights
For more than twenty years, businesses measuring and reporting their greenhouse gas emissions have worked across two parallel systems: the GHG Protocol and the ISO 14064 family of standards. Both are internationally recognised and widely respected, but using them side by side has often created unnecessary complexity. Differences in terminology, reporting requirements and verification processes have meant sustainability teams have spent time reconciling standards rather than focusing on reducing emissions.
That is now set to change.
In September 2025, the Greenhouse Gas Protocol and the International Organization for Standardization (ISO) announced a strategic partnership to harmonise their corporate greenhouse gas accounting standards. On 29 July 2026, the two organisations published further details of how that work will progress. Rather than continuing to maintain separate corporate standards, they will develop a single, co-branded framework that brings together GHG Protocol’s Corporate Standard, Scope 2 Guidance, Scope 3 Standard and Actions and Market Instruments work with ISO 14064-1.
A public consultation draft is expected during the second quarter of 2027, with the final standard anticipated in 2028. If delivered as planned, it will represent the most significant development in corporate carbon accounting since the original GHG Protocol Corporate Standard was introduced in 2001.
Carbon accounting is no longer simply a sustainability exercise. It underpins mandatory disclosure requirements, procurement decisions, investment assessments and customer expectations. As climate reporting has become more prominent, so too has the need for consistent methodologies.
Many organisations already report under the GHG Protocol while maintaining ISO certification or complying with additional national reporting requirements. Although the underlying principles are closely aligned, differences around organisational boundaries, terminology and acceptable market instruments have often resulted in duplicated work, additional assurance costs and unnecessary complexity.
The new joint standard aims to address that challenge by creating a common framework that can be applied consistently across reporting, assurance and certification.
The collaboration extends beyond organisational reporting. ISO and GHG Protocol have also established a separate programme to align product carbon footprint standards, with project-level greenhouse gas accounting expected to follow in due course. Together, these initiatives signal a broader move towards globally harmonised carbon accounting.
Alongside the partnership announcement, GHG Protocol also published the outcome of its long-running consultation on Scope 2 accounting.
Since the introduction of the Scope 2 Guidance in 2015, organisations have reported purchased electricity emissions using two complementary approaches: a location-based method, which reflects the average emissions intensity of the local electricity grid, and a market-based method, which reflects contractual purchases of electricity, including qualifying renewable electricity instruments.
The market-based approach has undoubtedly helped stimulate demand for renewable electricity. However, over the past decade an important question has gained increasing attention: does purchasing a renewable electricity certificate always contribute to additional renewable generation, or does it sometimes alter reported emissions without materially changing outcomes on the electricity system?
Investors, regulators, NGOs and businesses have increasingly called for greater transparency over what renewable electricity claims actually represent.
The consultation attracted almost 1,100 responses from stakeholders across 56 countries, highlighting the level of interest in what has traditionally been one of the more technical areas of greenhouse gas accounting.
The consultation has not introduced a new Scope 2 standard. Instead, it has provided a clear indication of the direction in which the revised guidance is likely to evolve.
Respondents broadly supported retaining both location-based and market-based reporting while strengthening the integrity of market-based claims through improved disclosure requirements and clearer criteria for qualifying instruments. There was also strong support for distinguishing between an organisation’s reported emissions and the wider impact of its purchasing decisions.
Rather than publishing a standalone revision to the Scope 2 Guidance, GHG Protocol has confirmed that this work will now form part of the joint corporate standard being developed with ISO.
Among the concepts currently being explored is a “multi-statement” reporting model, developed through the Actions and Market Instruments workstream. Rather than presenting a single emissions figure, this approach would separate operational emissions, market-based emissions and the impact of mitigation actions into distinct reporting statements. While this has not been adopted as the final approach, it reflects a broader move towards greater transparency around corporate climate claims.
For now, however, nothing changes. Organisations should continue reporting in line with the existing GHG Protocol Corporate Standard and Scope 2 Guidance until the revised standard is published.
Perhaps the most significant change is not a technical one but a philosophical one.
For many years, success in Scope 2 reporting has often been associated with achieving the lowest possible reported emissions, frequently through the purchase of renewable electricity certificates.
The emerging direction suggests a different emphasis: demonstrating that procurement decisions contribute to meaningful decarbonisation, supported by robust evidence and transparent disclosure. The focus is shifting from simply reporting lower emissions towards explaining how those reductions have been achieved and what they represent.
Although the new standard is not expected until 2028, organisations should begin preparing now.
Key priorities include:
In the meantime, organisations should continue reporting under the current GHG Protocol Corporate Standard and Scope 2 Guidance while monitoring consultation drafts as they are released. Those that strengthen their data, governance and procurement practices now are likely to find the transition considerably smoother once the revised framework comes into effect.
This partnership marks an important milestone in the evolution of corporate carbon accounting.
For years, sustainability professionals have questioned why voluntary standards, regulatory requirements and assurance frameworks have not aligned more closely. The collaboration between ISO and GHG Protocol represents a concerted effort to create a more coherent global approach.
It is unlikely to make carbon accounting less demanding. If anything, expectations around evidence, transparency and governance are set to increase. What it should do, however, is improve consistency, reduce duplication and give greater confidence in the emissions data that organisations publish.
Ultimately, accurate measurement has never been the end goal of carbon accounting. The real objective is to demonstrate credible progress towards a lower-carbon economy. As the next generation of standards takes shape, that distinction is becoming increasingly important.