GHG Protocol and ISO merger in 2026: what carbon data teams should do now

On 29 July 2026 the GHG Protocol announced that it will combine its corporate standards with ISO 14064-1 into one joint standard. This post covers what was announced, what still applies today, and what carbon data teams can do now.

What did the GHG Protocol and ISO announce?

The GHG Protocol will consolidate the Corporate Standard (2004), the Scope 2 Guidance (2015), the Scope 3 Standard (2011) and its Actions and Market Instruments workstream with ISO 14064-1. The stated aim is to reduce fragmentation, increase interoperability and give organisations one foundation for climate reporting.

The planned timeline has a consolidated public consultation in Q2 2027 and final publication of the joint standard in Q4 2028. The new standard is planned in two parts, with supplementary implementation guidance documents.

Do the current standards still apply?

Yes. The GHG Protocol states that the existing standards remain applicable while the new one is developed. Its guidance for now is to report physical inventory emissions, market-based emissions and the impact of climate actions separately and transparently, without combining them.

For Scope 3 teams, that means the Scope 3 Standard and its Category 1 methods are still the rulebook for the next reporting cycles. The four ways to calculate a Category 1 line (supplier-specific, hybrid, average-data and spend-based) are unchanged today.

What should carbon data teams do now?

Three habits will make any later change cheaper, whatever the final text says.

Record the method behind every figure. If a rule changes, you need to know which lines were calculated from a supplier's own data and which rest on a sector average, because those are the lines a new rule is most likely to touch.

Keep the source document and its date next to the number. A figure that can be traced to a named source can be re-examined. One that cannot has to be rebuilt.

Keep verification separate from calculation. ISO 14064-3 is the standard for verifying a greenhouse gas statement, and it is a different document from ISO 14064-1. Check what your data provider's assurance actually covers.

What does Verdantix say about the impact?

In its blog One Standard To Rule Them All? What The GHG Protocol-ISO Unification Means For Organizations And Carbon Management Software, Verdantix describes this as the first overhaul of the Corporate Standard since 2001 and puts the near-term impact for businesses as small. Its longer-term view is fewer duplicate audits and one methodology to train teams on.

"For businesses, near-term impact is small..." Alessandra Leggieri, Senior Analyst, Verdantix

Verdantix also raises a caveat. IFRS S2, the ESRS and the CSRD reference the existing GHG Protocol standard by name, so a unified standard does not automatically inherit that regulatory status, and how it will be folded into disclosure rules is not yet clear. For software providers, it points to the Scope 2 revision and a parallel product carbon footprint standard as the changes likely to arrive first.

How does DitchCarbon fit?

DitchCarbon records which of four methods produced each organisation's figure, with industry data fourth of four and used only where the first three could not be found. Every figure carries its source and change history, and source documents carry the assurance level they state, per scope. The calculator is verified to ISO 14064-3, limited assurance, by UL Solutions, renewed annually. The documents are in the trust centre.

That record is what a standards change tests: method per line, source behind each figure, and a visible trail of what changed.

The standard will take until the end of 2028 to settle. Method, source and change history on every figure are worth having before then.