On September 9, 2025, the Greenhouse Gas Protocol (GHG Protocol) and International Organization for Standardization (ISO) announced a new strategic partnership to harmonize and co‑develop greenhouse gas (GHG) accounting standards. This announcement raises the stakes for the GHG Protocol's ongoing update process, which promises significant changes to its existing suite of corporate standards and guidance.
Key Takeaways
- What's New: ISO and GHG Protocol will combine the ISO 1406x family with the GHG Protocol Corporate, Scope 2, and Scope 3 Standards into harmonized, dual-logo standards and will co-develop a new PCF standard.
- Why it Matters: A single, interoperable framework should reduce duplicative work and conflicting terminology, making it easier for companies, auditors, and policymakers to compare emissions data.
- Regulatory Context: The move aligns with calls for harmonization and with disclosure baselines such as ISSB/IFRS S2, which directly reference the use of the GHG Protocol for GHG measurement.
- What's Next: The GHG Protocol and ISO will likely begin developing work plans and drafts. This work will likely continue alongside the GHG Protocol's current work to conduct comprehensive updates to its corporate suite of standards and guidance.
The Announcement in Context
ISO and the GHG Protocol have announced a strategic partnership to harmonize their existing portfolios of GHG standards and co‑develop new, co‑branded standards. The collaboration will combine the ISO 1406x family with the GHG Protocol Corporate, Scope 2, and Scope 3 standards and guidance into harmonized, dual-logo standards, and will co-develop a new Product Carbon Footprint (PCF) standard.
Currently, GHG calculation and reporting standards have varying scopes and verification guidance, often leading to confusion by users—and sometimes verifiers— due to inherent comparability issues. The ISO and GHG Protocol partnership seeks to streamline terminology, measurement, and reporting. By unifying widely used corporate-level standards with product- and project-level approaches—and by issuing a joint PCF standard—the organizations aim to provide a cohesive toolkit for value-chain GHG emissions accounting and management. The initiative responds to longstanding user feedback about fragmentation across standards and verification guidance.
This effort also dovetails with the global disclosure landscape. The EU Corporate Sustainability Reporting Directive (CSRD) and IFRS S2, the new climate disclosure standard developed by the International Sustainability Standards Board (ISSB), point companies to the GHG Protocol when measuring emissions. A harmonized ISO–GHG Protocol framework will help companies align processes for regulatory disclosures, internal GHG inventories, product or company-level lifecycle analyses, and supplier requests.
What the Unified Standards are Expected to Cover
- Corporate accounting: Consolidated guidance for Scope 1, 2, and 3 measurement and reporting, built from ISO 1406x and the GHG Protocol Corporate/Scope 2/Scope 3 standards.
- Product-level accounting: A co-developed PCF standard to generate consistent, lifecycle-based product footprints suitable for supplier programs, procurement, and product claims.
Significance for the Business Community
Many organizations already anchor their emissions reporting on the GHG Protocol and have built systems around ISO 1406x. The work of this partnership should allow entities to converge GHG data collection and reporting to a single, credible standard set. Alignment across ISO and the GHG Protocol should also improve comparability; ease assurance dialogues with verifiers, auditors, and investors; and support the granular value-chain data needed to manage Scope 3 emissions and inform related product design and procurement decisions.
What's Next
Experts from both the GHG protocol and ISO will now collaborate through an integrated technical process to deliver the unified standards portfolio. While no formal timeline has been announced for the joint standards, early monitoring of work plans and drafts will help companies get ahead of transition impacts (e.g., recalibrating Scope 3 methods, refreshing supplier templates, and updating product claims protocols).
The announcement is also a further reason for companies to pay close attention to and consider engaging with the GHG Protocol's update process. Launched in late 2022, the update process is now well underway and covers the Corporate Standard, Scope 2 Guidance, and Scope 3 Standard. On July 14, 2025, the GHG Protocol's Independent Standards Board approved for fall 2025 public consultation draft revisions to the Scope 2 location-based and market-based methods. In parallel to the work on Scope 2, the GHG Protocol's Corporate Standard and Scope 3 standard/guidance are in development under workplans published in December 2024, along with cross-sector guidance on quantifying and reporting the GHG impacts of market-based approaches and interventions. The GHG Protocol aims to complete the update process by 2027, although these timelines are subject to change.
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