Carbon standards merge into single global framework

Two of the world’s most widely used greenhouse gas accounting systems are to be combined into a single corporate standard intended to reduce duplication and improve the comparability of emissions reporting.

The GHG Protocol and the International Organization for Standardization have agreed to develop a harmonised framework bringing together the GHG Protocol Corporate Standard, its Scope 1, Scope 2, and Scope 3 guidance, and ISO 14064-1.

An integrated public consultation is expected during the second quarter of 2027. The resulting standard would be designed for companies compiling emissions inventories across operations, purchased energy, products, suppliers, customers, and other value chain activities.

Multinational companies currently use several methodologies to meet investor, customer, regulatory, lending, and voluntary disclosure requirements. Differences in terminology, boundaries, calculations, and assurance processes can produce duplicated work and emissions totals that are difficult to compare.

Tim Mohin, chief executive of the GHG Protocol, said: “A consolidated corporate standard represents a significant step toward integrating and harmonising greenhouse gas accounting across the world. For the organisations applying these standards to measure their greenhouse gas emissions, a single corporate standard will simplify reporting, reduce duplication, and provide greater consistency across markets and jurisdictions. This will in turn allow companies to spend more time reducing emissions.”

The work will incorporate feedback from the continuing revision of Scope 2 guidance, which covers emissions associated with purchased electricity, heat, steam, and cooling. A recent consultation attracted almost 1,100 responses from 56 countries and exposed substantial differences over renewable energy contracts and market-based claims.

Scope 2 has become one of the most contested areas of corporate carbon accounting. Companies may report reductions by buying renewable electricity certificates or entering power purchase agreements, even when the physical electricity used at a particular location continues to come from a carbon-intensive grid.

Supporters of market-based accounting argue that procurement commitments direct capital towards new renewable generation. Critics contend that some instruments do not create sufficient additional capacity and can allow reported emissions to fall without changing the electricity system serving the company’s operations.

The combined standard will need to represent both physical emissions and contractual action without creating a methodology too complex for smaller organisations to apply. One option under consideration would separate location-based emissions, market-based claims, and the wider effect of energy procurement.

Greater consistency could reduce the time finance and sustainability teams spend mapping data between frameworks, reconciling organisational boundaries, and explaining why totals differ across reports. Assurance providers could also work from a more stable measurement base.

Commercial relationships are already affected by inconsistent carbon data. Large companies increasingly request emissions information from suppliers, while banks and investors use transition metrics within risk assessments. Suppliers can receive several versions of the same request, each based on different boundaries and calculation rules.

A shared standard could make bids, suppliers, and investment proposals easier to compare, although it will not remove differences in data quality. Smaller companies may still rely on estimates, industry averages, and customer assumptions where direct measurement is unavailable.

Regulatory alignment also remains uncertain. Governments and securities regulators may reference international standards while adding jurisdiction-specific requirements. A harmonised corporate methodology would create a common basis for calculation, but companies operating internationally would still need to satisfy local disclosure rules.

Governance will receive close scrutiny. A senior resignation at the GHG Protocol raised questions over oversight and representation, and the organisation’s influence will increase if its standards are combined formally with ISO’s framework.

Companies should not assume that harmonisation will remove judgement. Decisions about organisational boundaries, acquisitions, divestments, supplier data, renewable procurement, and the treatment of estimates will continue to affect reported totals.

Boards and audit committees will therefore need to understand the assumptions behind emissions figures rather than treating carbon accounting as a technical exercise delegated entirely to sustainability teams.

Implementation may require changes to data collection, internal controls, software, supplier engagement, and assurance contracts. Organisations designing reporting systems now will need enough flexibility to adapt when the combined framework is finalised.

The consultation process will determine whether the new standard can reduce duplication without concealing important distinctions between different forms of emissions reduction. A single framework will be useful only if its figures remain credible, understandable, and sufficiently consistent to support investment and operating decisions.