In a groundbreaking move, ISO and the Greenhouse Gas Protocol have forged a strategic partnership to harmonize their greenhouse gas standards. This collaboration aims to create a unified global language for emissions accounting, addressing the fragmentation of carbon accounting frameworks. By combining ISO's 1406X family of standards with GHG Protocol's widely adopted standards, the partnership promises to simplify reporting processes, increase data consistency, and reduce the measurement burden for all stakeholders. This consolidation represents a fundamental shift in how organizations will measure, report, and verify their greenhouse gas emissions. It addresses the current challenges of navigating multiple, sometimes conflicting requirements across different regions and reporting schemes. The unified approach will reduce compliance costs, improve data quality and comparability, strengthen stakeholder confidence, and provide a solid foundation for carbon pricing mechanisms and climate policies.
In a watershed moment for climate accountability, the International Organization for Standardization (ISO) and the Greenhouse Gas Protocol (GHG Protocol) announced a landmark strategic partnership on September 9, 2025. This historic collaboration aims to harmonize their existing portfolios of greenhouse gas standards and co-develop new standards for GHG emissions measurement and reporting, addressing one of the most significant challenges in corporate sustainability: the fragmentation of carbon accounting frameworks.
The partnership represents a fundamental shift in how organizations will measure, report, and verify their greenhouse gas emissions. By combining ISO’s 1406X family of standards with GHG Protocol’s widely adopted Corporate Accounting and Reporting Standard, Scope 2 Guidance, and Scope 3 Standard, the organizations seek to create a unified global language for emissions accounting. This consolidation promises to simplify reporting processes for companies, increase data consistency for policymakers, and reduce the overall measurement and reporting burden for all stakeholders.
“ISO is proud to announce this landmark partnership with GHG Protocol, which drives forward an ambition that enables co-creation, resulting in a harmonized portfolio of standards,” said Sergio Mujica, ISO Secretary General. “Both ISO and GHG Protocol have a shared vision to efficiently advance climate action and simplify the task for all stakeholders. This is a new era for the carbon accounting landscape and both organizations are thrilled to be working together.”
To understand the significance of this partnership, we must first recognize the complementary strengths and global influence of these two organizations. ISO, established in 1947, has developed over 25,000 international standards across virtually every industry. Its 1406X family of standards is used by governments worldwide in legislation and regulation, forming the foundation for GHG reporting and verification frameworks in many jurisdictions. Meanwhile, the GHG Protocol, launched in 1997 as a joint initiative of the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), has become the world’s most widely used greenhouse gas accounting standard, providing the underlying framework for nearly all GHG reporting programs and climate-related disclosure requirements globally.
The current sustainability reporting landscape is characterized by a proliferation of frameworks that has created significant challenges for reporting organizations. Companies operating globally often find themselves navigating multiple, sometimes conflicting requirements across different regions and reporting schemes. The most prominent frameworks include the International Sustainability Standards Board’s (ISSB) IFRS S2 Climate-related Disclosures, the European Sustainability Reporting Standards (ESRS) mandated by the EU’s Corporate Sustainability Reporting Directive (CSRD), the U.S. SEC’s climate disclosure rules, and California’s Climate Corporate Data Accountability Act (SB 253).
Each of these frameworks incorporates elements of GHG Protocol standards but with varying degrees of alignment and additional requirements. According to a January 2025 overview published by the GHG Protocol, there are notable differences in how these frameworks apply GHG Protocol methodologies, particularly regarding organizational boundaries, scope 2 reporting approaches, and scope 3 emissions requirements. This fragmentation has created significant resource demands on reporting organizations, undermined data comparability, and generated confusion in the market.
Geraldine Matchett, Steering Committee Chair of GHG Protocol, emphasized the user-centric nature of the collaboration: “We are very pleased to announce this historic agreement that leverages the respective strengths of both organizations. Harmonizing corporate, product and project-level GHG accounting standards is key. With users top of mind, this partnership establishes a new mechanism for long-term collaboration, demonstrating our commitment to reducing complexity in the field of international standards and allowing the development of the core frameworks needed to enable meaningful climate action across stakeholder groups.”
The technical integration of these standards will address several critical areas of carbon accounting. The partnership will combine standards from the ISO 1406X series and the GHG Protocol suite into one set of co-branded international standards. This will include a harmonized approach to organizational boundaries, operational boundaries covering Scope 1, 2, and 3 emissions, and alignment on methods for calculating Scope 2 emissions from purchased electricity and energy.
Additionally, the organizations will work on a joint product carbon footprint standard—reflecting the increasing demand from companies seeking granular data from across their value chain to guide decarbonization decisions. This comprehensive approach will bring technical rigor, policy relevance, and practical usability into one cohesive set of standards.
The implications for global climate policy and regulatory alignment are substantial. Emmanuel Faber, Chair of the International Sustainability Standards Board (ISSB), welcomed the development: “The ISSB welcomes this development which will augment the globally accepted baseline for greenhouse gas accounting. Consistent, comparable carbon data is essential for investors globally enabling informed capital allocation decisions.”
This partnership aligns with the broader trend toward convergence in sustainability reporting. Rather than competing or operating in parallel, major standard-setting bodies are increasingly collaborating to reduce market confusion and reporting burden. The ISO-GHG Protocol agreement represents the most significant move yet toward a single global system for emissions accounting, potentially serving as a foundation for future integration of other sustainability reporting domains.
The implementation of the unified standards will require careful transition planning by organizations. While the exact timeline for implementation has not been announced, companies currently using either ISO or GHG Protocol frameworks should begin preparing for the transition. This includes reviewing existing GHG accounting methodologies, identifying gaps in data collection systems, and developing a roadmap for adoption once the harmonized standards are released.
For organizations, the benefits of this harmonization are multifold. First, the unified approach will reduce compliance costs by eliminating the need to report under multiple frameworks. Second, consistent methodologies will improve data quality and comparability, enabling more meaningful benchmarking and target-setting. Third, the standardized approach will strengthen stakeholder confidence in reported emissions data, potentially reducing greenwashing concerns. Finally, the harmonized standards will provide a more solid foundation for carbon pricing mechanisms, emissions trading schemes, and other market-based climate policies.
“This partnership is a timely and critical step toward greater climate accountability,” said Dan Ioschpe, COP30 High-Level Champion. “A unified set of standards for GHG emissions reporting will help raise ambition, enable credible net-zero pathways, and build trust across borders. As countries prepare for COP30, clarity and consistency in carbon accounting are essential to accelerating progress on the Paris Agreement goals.”
The financial community has also welcomed the move. Clara Barby, Senior Partner at Just Climate, noted: “Investors need consistent, reliable data to deploy capital effectively in the transition to a low-carbon economy. Together ISO and GHG Protocol can provide coherent protocols as the basis for disclosure regimes globally, offering the credibility and simplicity the market needs.”
Looking ahead, the ISO-GHG Protocol partnership sets the stage for further evolution in sustainability reporting. As climate disclosure increasingly becomes mandatory across jurisdictions, the harmonized standards will provide a crucial foundation for regulatory alignment. Moreover, as reporting matures, the focus is likely to shift from merely disclosing emissions to demonstrating tangible progress toward reduction targets. The unified framework will facilitate this transition by establishing consistent baselines and methodologies for tracking emissions over time.
The partnership also comes at a critical juncture in global climate policy. With COP30 on the horizon and countries preparing to submit enhanced Nationally Determined Contributions under the Paris Agreement, standardized emissions accounting will be essential for tracking collective progress toward global climate goals. The harmonized standards will support both corporate and national climate commitments by providing a common language for measuring and reporting emissions.
For organizations seeking to navigate this changing landscape, proactive preparation is essential. Companies should stay informed about the development of the unified standards, assess the implications for their existing reporting processes, and begin building internal capacity for implementation. Engaging with industry peers, reporting organizations, and standard-setters during the transition period will also be valuable for sharing best practices and addressing common challenges.
The ISO-GHG Protocol partnership represents a pivotal moment in the evolution of climate accountability. By bringing together the world’s two leading carbon accounting frameworks, this collaboration promises to streamline reporting processes, improve data quality and comparability, and ultimately accelerate global climate action. As organizations worldwide adopt these harmonized standards, we can expect to see a more coherent, transparent, and effective approach to emissions measurement and management—a critical foundation for meaningful progress toward a low-carbon future.
As experts from both organizations begin collaborating through an integrated technical process, the goal is clear: delivering cohesive standards that meet the needs of all users and support robust, science-based decarbonization across regions, sectors, and economies. For the thousands of organizations currently navigating the complex landscape of sustainability reporting requirements, this unified approach can’t come soon enough.
