The new partnership between ISO and GHG Protocol and its significance for companies

On September 9, 2025, the International Organization for Standardization (ISO) and the GHG Protocol officially announced their new strategic partnership. The aim of this collaboration is to develop common and harmonized standards for greenhouse gas reporting in the future, thereby addressing one of the biggest problems in ESG and climate reporting: the fragmentation of regulations, methods, and terminology.

This announcement is highly relevant for companies. It affects not only the calculation and reporting of emissions, but also compliance, auditability, data processes, and long-term investment decisions.

The following remarks provide a structured overview of the cooperation, explain the most important background and objectives, and highlight the implications that are particularly relevant for companies.

Starting point: Why this partnership is necessary

GHG reporting has developed rapidly in recent years. At the same time, the landscape of standards has become increasingly complex:

• The GHG Protocol is recognized worldwide as the de facto standard for accounting for Scope 1, 2, and 3 emissions and forms the methodological basis for many regulatory and voluntary reporting requirements.
• With the ISO 14000 family, ISO publishes internationally recognized, certifiable standards, e.g., for carbon footprints, verifications, and management systems.
• Regulatory requirements such as CSRD, SEC climate rules, ISSB, or national laws take up these standards, but sometimes interpret them differently or supplement them with their own logic.

The result is a methodologically fragmented reporting landscape. Many companies record and report emissions that are comparable in terms of content, but based on different definitions, system boundaries, and calculation approaches. This leads to increased coordination efforts, limited comparability, uncertainties in audits, and an increased risk of inconsistent ESG statements.

This is precisely where the partnership between ISO and GHG Protocol comes in. It responds to the growing need for consistency, clarity, and globally compatible foundations in GHG accounting, thereby creating the conditions for robust, comparable, and long-term stable emissions data in an increasingly regulated environment.

The goal of the partnership: harmonization instead of parallel worlds

ISO and GHG Protocol are pursuing a clear common goal with their partnership: a globally coordinated, consistent, and compatible foundation for greenhouse gas reporting. The focus is on overcoming existing parallel worlds in methodology, terminology, and application practice.

What does harmonization mean in concrete terms?

• Alignment of methodological logic, for example in terms of system boundaries, emission factors, calculation approaches, and the mapping of Scope 1, Scope 2, and Scope 3 emissions
• Reduction of duplication of work through more consistent bases for calculation, documentation, and reporting
• Improved comparability of emissions data across companies, industries, and regions
• Increased audit and legal certainty through clearer, better coordinated requirements
• Greater connectivity to regulatory ESG requirements, which are increasingly based on internationally recognized standards

Which areas does harmonization cover?

Harmonization does not only apply to company-related emissions accounting. The partnership covers several levels of carbon accounting, including accounting at the company, product, and project levels, as well as the verification of emissions data.

These include the ISO 1406x series (corporate, product carbon footprint, project accounting, and verification), the GHG Protocol Corporate Standard including Scope 2 Guidance and Scope 3 Standard, and the further development of a common product carbon footprint standard. For the first time, product-related emissions accounting is also becoming a greater focus of harmonization; an area that is becoming increasingly important, particularly for supply chain management, CBAM implementation, and decarbonization strategies in Europe.

In addition, the partnership aims not only to harmonize existing regulations, but also to develop new, co-branded standards. These standards are intended to combine the methodological logic of the GHG Protocol with the formal structure and verifiability of ISO standards and serve as a uniform reference in the future. In the long term, the aim is to create a common reference framework for emissions management that meets both the practical requirements of corporate reporting and the formal expectations of regulators, auditors, and capital markets.

ISO vs. GHG Protocol: a structured comparison

To better understand the significance of the partnership, it is worth taking a look at the different roles and focuses of ISO and GHG Protocol. Both have established themselves as key references in greenhouse gas reporting in recent years, but they pursue different approaches and objectives. The cooperation does not aim to replace existing standards, but rather to closely integrate their respective strengths. The following comparison shows how the two frameworks have complemented each other so far.

Significance for CSRD, audits, and investors

The desired harmonization of ISO standards and GHG Protocol standards is particularly relevant in the regulatory and audit-related environment. There, it acts as a connecting element between methodological emissions accounting, formal audit requirements, and capital market-oriented reporting.

This is particularly relevant in the context of:

• CSRD & ESRS: Consistent emissions data can be used across different reporting formats without methodological inconsistencies or multiple preparations.
• Auditability: Clearly coordinated definitions and calculation logic facilitate the traceability and auditing of emissions data.
• Investors & banks: Comparable emissions metrics are becoming increasingly important for valuations, ratings, and financing decisions.
• Supply chains & Scope 3: Harmonized approaches reduce methodological inconsistencies in the collection and reporting of emissions data along the value chain.

For internationally active companies, this means a noticeable reduction in workload overall. The risk of having to meet regional or regulatory requirements multiple times, in different ways, or in contradictory ways is reduced in the long term.

What specifically will change for companies?

The effects of the partnership will not unfold completely overnight. Rather, a gradual development can be expected, with effects that will be felt differently in the short, medium, and long term. The following points provide an overview of the most important changes from a corporate perspective.

Short term

• No immediate obligation to switch
• Existing GHG Protocol inventories remain valid
• ISO standards remain applicable

Medium term

• Convergence of terms, definitions, and calculation logic
• Less room for interpretation in Scope 3 categories
• Clearer requirements for data quality and documentation

Long term

• Uniform basis for regulatory reporting
• Simplified reviews and audits
• More stable investment and transformation decisions

5 steps companies should take now to prepare

Even though the new, harmonized standards for climate reporting are still under development, companies can already take important steps today.

The following five steps will help you make your GHG accounting future-proof, consistent, and compatible.

1. Review existing emissions methodology: The current methodology should be reviewed for consistency, complete documentation, and traceability, especially with regard to system boundaries, assumptions, and emission factors used.
2. Ensure GHG Protocol-compliant data structures: A clear mapping of Scope 1, 2, and 3 and a clear allocation of emission sources form the basis for comparability and future harmonization.
3. Consider ISO proximity in processes: Processes should be designed to be auditable and verifiable, for example through clear responsibilities, reliable evidence, and traceable audit trails.

4. Use flexible systems and software: The tools used should be able to reflect methodological adjustments, new definitions, and future standard changes without fundamental system breaks. 

   Tip: With Envoria software, product carbon footprints can already be determined today based on established GHG Protocol and ISO-compliant methodologies. The tool will also support the mapping of the planned co-branded standard from ISO and GHG Protocol.

5. Actively monitor standard developments: The partnership is gradually taking shape. Continuous monitoring of new guidelines, pilot standards, and consultations enables early adaptation of your own reporting strategy.

Outlook: Important milestones of the new partnership

The strategic partnership between ISO and GHG Protocol marks a turning point in global emissions reporting. For companies, it means greater clarity, higher comparability, and less complexity in the long term, provided that their own processes are properly set up.

• Fall 2025: Launch of joint working structures and joint working groups to harmonize existing standards
• 2026:
  • Initial drafts and consultations for jointly developed (“co-branded”) standards, particularly in the area of product carbon footprint (PCF).
  • Involvement of ISO experts in ongoing revisions of key GHG Protocol standards (including Corporate, Scope 2, Scope 3).
  • Expected public consultation draft for the next version of the GHG Protocol Corporate Standard (mid-2026)
• 2027: Gradual finalization of the first harmonized standards and integration into regulatory and audit-related contexts.