GHG Protocol, ISO to combine carbon accounting standards

The Greenhouse Gas Protocol and ISO are merging their corporate carbon accounting frameworks into a single standard, with a draft due next year. This move addresses a fragmentation problem that has plagued corporate emissions reporting for two decades – companies have navigated competing methodologies, scope definitions, and verification requirements. The unified standard will likely anchor scope 1, 2, and 3 emissions calculations to a single set of rules rather than forcing organisations to reconcile overlapping guidance.

The stakes are material. Investors, regulators, and disclosure bodies already mandate GHG Protocol alignment for most major corporate reporting; ISO's parallel standard has gained traction in specific sectors and geographies, but the duplication wastes compliance resources and creates audit friction. A combined framework should reduce reporting cost and increase comparability – which is the actual point of standardisation.

But convergence isn't guaranteed to be clean. The draft will need to navigate territory where ISO and GHG Protocol have diverged on specifics: upstream scope 3 boundaries, avoided emissions counting, and geographic scope rules. If either party waters down rigour to achieve consensus, the standard loses credibility with investors and science-based target bodies like SBTi.

The real test arrives when organisations implement. A merged standard only matters if verification bodies, auditors, and disclosure platforms accept it, and if companies actually adopt it instead of running parallel calculations. The question isn't whether one standard is better than two – it's whether the combined version will be more useful or just larger.