One GHG Inventory for GRI 102, ESRS E1 and IFRS S2: Boundaries, Metrics and Remaining Gaps

Technical status: source-grounded publication draft; final human technical review required before release.

The physical activity does not change when the reporting framework changes. A litre of diesel, a megawatt-hour of electricity, a tonne-kilometre of freight and a unit of product sold can feed the same controlled calculation engine. This creates a strong case for one source-data and calculation core.

The reporting question does change. GRI asks for information about the organisation’s significant climate impacts. ESRS applies double materiality and adds its own reporting-boundary and presentation rules. IFRS S2 asks for material information for investors about climate-related risks and opportunities that could affect the entity’s prospects. Therefore, the inventory should be shared, while materiality decisions, boundary overlays, presentation and narrative outputs remain explicit.

A shared inventory is reliable only when it stores the facts needed to recreate different reporting views. A flat spreadsheet containing one total per scope is not a reusable inventory. It is a final output with the decision trail removed.

Figure 1. One controlled GHG data core can feed three framework-specific reporting adapters.

Source activity data. Fuel, refrigerants, electricity, heat, steam, cooling, purchased goods, logistics, travel, commuting, assets, sales, product-use and end-of-life data can be collected once with controlled units and periods.

Emission factors and GWP values. A central library can hold approved sources, versions, geographic and technological representativeness, gas coverage and recalculation status.

Scope 1-3 calculation logic. Formulae, allocation, sampling, extrapolation and category models can be used across outputs when their boundaries and methods satisfy each framework.

Data-quality and estimate records. Primary/secondary status, uncertainty, representativeness, supplier methodology and improvement actions are relevant across all three frameworks.

Controls and evidence. Reconciliations, change approvals, reviewer sign-off, source extracts and retention rules support every reporting route and future assurance.

Operational reduction analysis. Category hotspots and emissions drivers can inform targets and transition actions, even though each framework asks different narrative questions.

The matrix below separates a common data field from a common reporting requirement. Similarity is not the same as equivalence, and a framework can require additional disaggregation or context even where the underlying tonnes of CO2e are produced by the same model.

Figure 2. Cross-framework gap matrix: shared calculations sit beneath different materiality, boundary and narrative requirements.

Most cross-framework differences arise before a formula is applied. The inventory needs a controlled register of legal entities, sites, ownership periods, contractual arrangements, leased assets, joint operations, associates and joint ventures. For each source, store the entity that owns it, the party that operates it, the percentage and period of control, and the classification under each reporting view.

GRI 102 requires the organisation to report the consolidation approach - equity share, financial control or operational control - and apply it consistently across Scope 1, Scope 2 and Scope 3. ESRS E1 starts from the consolidated accounting group and has specific operational-control treatment and disaggregation for associates, joint ventures, unconsolidated subsidiaries and certain joint arrangements. IFRS S2 requires the GHG Protocol Corporate Standard approach unless an applicable jurisdictional or exchange requirement permits another method.

A practical shared engine should calculate location-based and market-based Scope 2 whenever contractual instruments are used, even though the publication emphasis differs. GRI 102 requires location-based and, if applicable, market-based Scope 2. ESRS E1 requires both and uses them to present two total-GHG views. IFRS S2 requires location-based Scope 2 and information about contractual instruments necessary to understand the emissions; a separate market-based figure can be useful but should not replace the required location-based metric.

The safest common denominator is a register containing all 15 GHG Protocol categories. GRI 102 requires the category breakdown. ESRS E1 requires screening of all 15 and disclosure of each significant category, along with included/excluded categories and justifications in the application guidance. IFRS S2 requires the entity to consider the 15 categories and disclose the categories included in its Scope 3 measure, using its Scope 3 measurement framework.

The December 2025 IFRS S2 amendments add a Category 15 permission: an entity may limit Category 15 to financed emissions, with specified explanations and disclosures. That relief does not automatically change GRI 102 or ESRS E1 requirements. The data architecture should therefore retain the full Category 15 population, the IFRS-limited population where used, and a bridge explaining the difference.

The direction matters: IFRS S2 GHG disclosures can satisfy the corresponding GRI 102 emissions requirements when the conditions are met. The statement does not say that a GRI 102 disclosure automatically satisfies all IFRS S2 requirements, and it does not extend equivalence to transition plans, impacts, targets, financial effects or other climate disclosures.

The December 2025 IFRS S2 amendments also allow an entity, in specified circumstances, to use a jurisdictional or exchange-required GHG measurement method instead of the GHG Protocol Corporate Standard. A company using that relief should not assume it still meets the joint GRI equivalence condition. It should perform a separate GRI 102 gap test and either maintain a GHG Protocol view or report the GRI requirements directly.

A GHG inventory is an input, not a transition plan. It can show the emissions baseline, category mix and progress, but it cannot by itself explain the organisation’s significant impacts, strategic response, dependencies, resilience, capital allocation, just-transition effects or current and anticipated financial effects.

Lock the source set. Record the current GRI 102, ESRS E1, IFRS S2 and GHG Protocol editions, effective dates, amendments and legal applicability assumptions.

Create the entity-and-operation register. Map legal consolidation, ownership, operational control, joint arrangements, leased assets and changes during the period.

Define the common data dictionary. Standardise activity units, gases, factor fields, location, technology, category, period, owner, evidence and review status.

Build the calculation core. Preserve gas-level calculations, gross emissions, both Scope 2 views, all 15 Scope 3 categories, biogenic fields, base year and recalculation logic.

Apply framework boundary flags. Generate GRI, ESRS and IFRS views from the same source records and reconcile the bridges.

Run separate materiality gates. Approve the GRI impact conclusion, ESRS double-materiality conclusion and IFRS investor-materiality conclusion independently.

Generate framework adapters. Produce required disaggregation, method notes, category lists, omissions/reliefs, Content Index references and disclosures.

Complete the residual-gap matrix. Assign owners for targets, transition plans, impacts, financial effects and framework-specific narrative evidence.

Sign off the claims. Approve which standards are applied, whether GRI-IFRS equivalence is used, which reliefs are used, and where each disclosure is published.

The company creates one entity register and marks the joint venture as outside the financial consolidation group but within an operational-control overlay for the relevant ESRS view. The GRI and IFRS views are generated according to the selected GHG Protocol consolidation approach. The source-level records remain the same; only the inclusion and presentation flags differ.

For Scope 2, the engine calculates location-based emissions for every site and a market-based view where qualifying instruments exist. For Scope 3, all 15 categories stay in the register. The ESRS output publishes significant categories, the GRI output provides the category-by-category disclosure, and the IFRS output identifies the included categories. Because the group uses the GHG Protocol Corporate Standard, it elects to use the IFRS S2 emissions disclosures for the corresponding GRI 102 requirements and maps them precisely in the GRI Content Index.

The group does not describe the frameworks as fully equivalent. Finance separately assesses material climate risks and anticipated financial effects; the GRI team assesses significant climate impacts and just-transition effects; and the ESRS team documents both materiality lenses and the required boundary disaggregation.

FAQ candidates

One GHG inventory architecture

Figure 1. One controlled GHG data core can feed three framework-specific reporting adapters.

Cross-framework GHG gap matrix

Figure 2. Cross-framework gap matrix: shared calculations sit beneath different materiality, boundary and narrative requirements.

Update triggers

A revised or amended GRI 102, GRI-IFRS equivalence statement or GRI FAQ.

A delegated act adopting amended or simplified ESRS, or new EFRAG implementation guidance affecting E1-6.

Further IFRS S2 amendments, TIG decisions or educational material affecting GHG measurement or reliefs.

Final revised GHG Protocol Corporate, Scope 2 or Scope 3 standards.

Change in the organisation’s reporting boundary, consolidation approach or early-adoption decision.

A new assurance finding indicating that the boundary bridge, factor library or framework adapters are not controlled.

Technical-review flags

Recheck the enacted ESRS text and any final European Commission simplification immediately before publication.

Validate the IFRS S2 HTML/PDF source URL and paragraph references after integrating the December 2025 amendments.

Technical reviewer should confirm the one-way equivalence analysis where an IFRS jurisdictional-method relief is used.

Obtain finance review of all statements about current and anticipated financial effects.

Do not reuse the boundary-case table as a company conclusion without contract, ownership and operational-control evidence.

Confirm whether the organisation early adopts the IFRS S2 2025 amendments and update effective-context wording accordingly.