GHG Protocol and ISO agree to unify their greenhouse gas standards

What happened

On 9 September 2025 in Washington, the International Organization for Standardization (ISO) and GHG Protocol announced a strategic partnership. The two organisations agreed to harmonise their existing greenhouse gas standards and to develop new standards together.

According to the announcement, the partnership covers the following:

• The ISO 1406X family of standards (including ISO 14064-1 for corporate inventories) and the GHG Protocol Corporate Accounting and Reporting Standard, Scope 2 Guidance and Scope 3 Standard will be merged into co-branded international standards.
• Experts from both organisations will work together in an integrated technical process.
• A joint product carbon footprint standard will be developed.

The announcement did not include a date or transition timeline for the validity of existing standards. A concrete timeline was announced in July 2026: public consultation on the unified corporate standard is planned for the second quarter of 2027 and publication for the last quarter of 2028 (details).

Who is affected

Turkish companies that use both frameworks (for example GHG Protocol for SBTi and CDP reporting and ISO 14064-1 for verification) are the most directly affected. This dual setup can lead to differences in boundary setting, category naming and reporting format. Over the long term, a unified standard could make it easier to use a single inventory for both reporting and verification. Because TSRS 2, Türkiye's climate disclosure standard aligned with IFRS S2, also relies on GHG Protocol for greenhouse gas measurement, the unified standard will indirectly affect companies reporting under the Turkish Sustainability Reporting Standards (TSRS) as well.

On the product carbon footprint side, a common standard could reduce the need for Turkish exporters, whose EU customers ask for product-level data, to repeat calculations with different methods.

What companies should do

• Keep reporting under the existing standards for now; no change has taken effect.
• Document the mapping between GHG Protocol and ISO 14064-1 in your inventory (category equivalents, boundary definition); this mapping will make the transition easier.
• Record the method and data sources you use in your product carbon footprint work.

Alalëa supports inventory preparation aligned with GHG Protocol and ISO 14064-1: carbon footprint.