GHG Protocol Corporate Standard

1. Standard Overview & Historical Context

The GHG Protocol Corporate Accounting and Reporting Standard was developed jointly by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), first published in 2001 and revised in 2004. The 2004 revised edition remains the operative version. No subsequent full revision has superseded it; the supplementary GHG Protocol Scope 2 Guidance (2015), the Corporate Value Chain (Scope 3) Standard (2011), and the Land Sector and Removals Standard (January 2026) extend — rather than replace — the Corporate Standard’s foundational architecture.

The Standard requires that organisational GHG inventories satisfy five principles: relevance, completeness, consistency, transparency, and accuracy. These are not best-practice suggestions. They function operationally as audit criteria against which third-party verifiers and assurance providers test methodological adequacy. Failure on any one principle — for example, omitting a material Scope 3 category without justification (completeness), or reporting a single CO₂e total without gas disaggregation (transparency) — constitutes a methodological deficiency, not a stylistic preference.

Why It Became the Global Default

The Corporate Standard achieved universal adoption through two reinforcing mechanisms. First, it was the earliest publicly available, methodologically rigorous framework for corporate GHG accounting; first-mover advantage cemented its position before competing standards matured. Second, downstream frameworks — CDP, the UN Global Compact, the Science Based Targets initiative (SBTi), GRI 305, and most recently the EU’s CSRD ESRS E1 — built their reporting requirements on top of the Corporate Standard rather than alongside it. The result is a self-reinforcing compliance ecosystem: an organisation that does not produce a GHG Protocol-aligned inventory cannot, in practice, satisfy the disclosure obligations of any major reporting framework.

Scope of This Page

This reference covers the Corporate Standard exclusively. It does not address the methodology of the Scope 3 Standard in detail (see Scope 3 Standard), the Project Protocol, or the Land Sector and Removals Standard (see Land Sector Standard). Where Scope 3 categories are referenced below, the treatment focuses on classification and boundary placement under the Corporate Standard rather than the calculation methodologies in the Scope 3 Standard itself.

2. The GHG Protocol Standards Hierarchy

The Corporate Standard sits at the apex of a layered standards architecture. Each subsequent document presupposes alignment with the foundational Standard.

3. Organisational Boundaries

Boundary definition is where most inventories fail and where most audits concentrate scrutiny. The Corporate Standard offers three approaches; selecting the wrong one — or applying the correct one inconsistently across the inventory — is the single most common cause of material misstatement in corporate GHG reporting.

3.1 The Three Boundary Approaches

3.2 Choosing an Approach

The Corporate Standard does not rank the three approaches or apply them in sequence. A company chooses one consolidation approach for its whole inventory and documents why. The choice should follow how the company is actually organised and how it reports financially:

1. Pick one approach for the whole inventory. Equity share, financial control or operational control. The standard asks that the approach be applied consistently across all operations and disclosed.
2. Under a control approach, it is 100% or nothing. An operation the company controls is counted in full; an operation it does not control is counted at zero in Scopes 1 and 2, however large the shareholding. Equity share is not a fallback for operations that fail a control test; it is a separate approach.
3. Check against the financial accounts. Financial control follows the accounting consolidation; equity share follows economic interest. Where the two would give materially different pictures, the standard encourages reporting on both an equity and a control basis.
4. Record uncontrolled operations elsewhere. Emissions from operations excluded by the chosen approach can appear in Scope 3, for example Category 15 (Investments) for joint ventures and associates, or Category 8 or 13 for leased assets.

3.3 Boundary Scenarios

4. Scope Classification

4.1 Scope 1 — Direct Emissions

Scope 1 covers GHG emissions from sources owned or controlled by the reporting organisation. The Corporate Standard divides Scope 1 into four operational source categories:

• Stationary combustion — boilers, furnaces, turbines, and on-site generators burning fossil or biomass fuels
• Mobile combustion — company-owned or operationally controlled road vehicles, aircraft, vessels, and rolling stock
• Process emissions — chemical or physical industrial processes not involving combustion (cement clinker calcination, primary aluminium smelting, ammonia synthesis, refrigerant production)
• Fugitive emissions — intentional or unintentional releases: refrigerant leaks from HVAC and refrigeration; methane from coal mining and natural gas distribution; SF₆ from electrical switchgear; HFCs from foam blowing

Biogenic CO₂ treatment. CO₂ from combustion of biomass (wood, biogas, biofuel, biogenic municipal waste) is excluded from the Scope 1 total but must be reported separately as a memo item. Failing to disclose biogenic CO₂ as a supplementary figure is a Corporate Standard compliance failure, not an editorial choice. The non-CO₂ biogenic emissions (CH₄, N₂O) remain in Scope 1.

Refrigerant fugitives. Fugitive emissions from HVAC and refrigeration systems are Scope 1. They are routinely missed because they require equipment-level records, annual leak detection logs, and refrigerant-specific GWP application — not utility meter readings. In commercial real estate and food retail they can be one of the largest Scope 1 sources and are a focal point of verification scrutiny.

4.2 Scope 2 — Indirect Energy Emissions

Scope 2 covers emissions from the generation of purchased electricity, steam, heat, or cooling consumed by the reporting organisation. The 2015 Scope 2 Guidance requires dual reporting for any company with operations in markets where contractual instruments such as certificates or supplier-specific rates are available.

Critical decision point. Dual reporting depends on the market, not on what the company holds. A company operating where certificates or supplier-specific rates exist reports both figures even if it holds no instruments; its market-based figure then uses supplier rates or the residual mix (in Europe, the AIB residual mix). Reporting only a market-based zero-emission figure without the location-based disclosure does not meet the Scope 2 Guidance, and the location-based figure keeps market-based zero claims from obscuring grid-driven emissions.

Quality criteria for market-based instruments. The Scope 2 Guidance specifies eight Scope 2 Quality Criteria that contractual instruments must meet to be used in the market-based method, covering among other things attribute conveyance, exclusivity (no double-counting), tracking and redemption, vintage proximity to the reporting period, geographic relevance to the consumption market, and explicit retirement or cancellation in the consumer’s name. Where instruments fail these criteria, the market-based figure falls back to supplier rates or the residual mix. The GHG Protocol consulted on revisions to the Scope 2 Guidance between 20 October 2025 and 31 January 2026; until a revised version is published, the 2015 Guidance applies.

4.3 Scope 3 — Value Chain Emissions

Scope 3 covers all indirect emissions not captured in Scope 2 — spanning upstream and downstream activities across the value chain. Under the Corporate Standard, Scope 3 is an optional reporting category: companies “shall” account for and report Scopes 1 and 2, and “may” report Scope 3. The stricter rule comes from the separate Scope 3 Standard: a company claiming conformance with it must report all relevant categories and justify any exclusions. In practice Scope 3 is expected by most frameworks that build on the GHG Protocol — CDP, SBTi and, where material, CSRD’s ESRS E1.

Detailed quantification methodology resides in the separate Corporate Value Chain (Scope 3) Standard (2011). The classification table in Section 5 is authoritative under the Corporate Standard; calculation methodologies fall to the Scope 3 Standard.

5. Scope 3 Category Reference

6. GWP Values & Gas Disaggregation

6.1 GWP Reference Table — IPCC AR6 (100-year)

^† AR6 gives separate GWP-100 values for fossil and non-fossil methane; AR5 gave one value, 28, for both. The GHG Protocol’s GWP table (v2.0, 7 August 2024) says the fossil value applies only to fugitive emissions from fossil sources (oil and gas systems, coal mining) and to industrial processes where the carbon in the methane is fossil. All other methane, including stationary and mobile combustion of fossil fuels, uses the non-fossil value, because the CO₂ from oxidising that methane is already counted in the combustion CO₂. Sources: IPCC AR6 WGI Table 7.15 and Table 7.SM.7; GHG Protocol, IPCC Global Warming Potential Values v2.0. See Land Sector and Removals Standard for agricultural inventories.

^‡ The HFC range runs from HFC-41 to HFC-23 among the single-compound HFCs on the same basis in each column; some compounds counted as HFCs in AR5 are classed as HFOs in AR6. Blends such as R-410A fall inside the range. GreenCalculus implements the four most common refrigerant HFCs in corporate inventories (HFC-134a, HFC-32, HFC-404A, HFC-410A) plus less common compounds where activity data warrants. See the complete AR6 GWP dataset for all reported gases including HFOs.

6.2 The AR5 → AR6 Transition

The IPCC Fifth Assessment Report (AR5, 2013) was the operative basis for corporate inventories from approximately 2014 through 2021. AR6 (2021) updates GWP values across most gases. The most consequential shifts for corporate inventories:

• N₂O: 265 → 273 (+3.0%). Material for agricultural sectors, wastewater operators, and fertiliser-intensive supply chains.
• SF₆: 23,500 → 24,300 (+3.4%). Material for utilities and electrical equipment manufacturers.
• Fossil CH₄: 28 → 29.8 (+6.4%). Material for oil & gas, coal, and natural gas distribution.
• HFC-32: 677 → 771 (+13.9%). Material for HVAC and lower-GWP refrigerant transitions.
• Fossil/non-fossil CH₄ separation: AR6 gives distinct values where AR5’s headline table gave a single value (28; its 30 for fossil methane was not adopted by the UNFCCC). Under the GHG Protocol, combustion methane takes the lower non-fossil value; only fossil fugitive and process methane takes the higher one.

The GHG Protocol recommends AR6 for all new inventories and base-year recalculations. Organisations still applying AR5 should disclose the rationale and plan a transition. The revised ESRS E1 (Delegated Regulation (EU) 2026/1563) requires the most recent IPCC GWP-100 values, currently AR6, and asks for an explanation where older values are used.

6.3 Gas Disaggregation Requirement

At minimum, inventories must disclose CO₂, CH₄, N₂O, and the F-gas groups (HFCs, PFCs, SF₆, NF₃) where applicable to the organisation’s activities. Sector-specific high-impact gases require compound-level disclosure: HFO refrigerants in food retail and automotive AC; specific PFCs in semiconductor fabrication; specific HFCs in the air conditioning industry.

7. Emissions Calculation Logic

7.1 The Core Formula

Activity data is the quantitative measure of an activity that drives emissions: litres of fuel consumed, kWh of electricity purchased, kilometres driven, tonnes of waste disposed, kilograms of refrigerant charged. Activity data must be measured, metered, or calculated from primary records. Estimated values are permitted only with explicit disclosure of the estimation methodology and rationale — estimation without disclosure fails the transparency principle.

Emission factor is the mass of GHG released per unit of activity. Factors vary by fuel type, technology, geography, grid mix, and process. Factor selection is the most consequential methodological decision in inventory construction, the most frequently contested item in third-party verification, and the largest source of year-on-year inventory variance unrelated to actual emissions changes.

GWP converts gas-specific emissions to carbon dioxide equivalent (CO₂e), enabling aggregation across gases. The Corporate Standard requires explicit disclosure of the GWP source, version (e.g. IPCC AR6), and time horizon (typically 100-year) applied across the inventory.

7.2 Emission Factor Selection Hierarchy

8. Data Quality & Tiering

The Corporate Standard does not prescribe a formal data quality scoring system. The Scope 3 Standard introduces a five-criterion data quality indicator (DQI) covering technological, geographical, temporal, completeness, and reliability dimensions. PCAF, CDP, and CSRD assurance providers have converged on tiered data hierarchies that practitioners should adopt regardless of which framework triggers the requirement.

9. Base Year & Recalculation Policy

The Corporate Standard requires every inventory to declare a base year — the historical reference period against which subsequent emissions are tracked. The base year is the operative anchor for target-setting (SBTi commitments use the base year as the reference for absolute or intensity reduction targets), trend disclosure, and consistency assessment.

9.1 Base Year Selection Criteria

• Verifiable data. The base year must rest on data of comparable quality to current-year reporting. Selecting a base year with materially weaker data quality than the current year creates a non-comparable baseline.
• Representative period. Avoid years with anomalous events that materially distort the baseline (production disruptions, plant outages, pandemic-driven activity drops). Where the most recent verifiable year is anomalous, an earlier representative year is preferred.
• Documentation. The selection rationale must be documented and consistent. Changing the base year mid-trajectory requires explicit recalculation disclosure.

9.2 Recalculation Policy — Significance Triggers

The Corporate Standard requires base-year recalculation when a structural change is significant enough to materially affect base-year emissions. The Standard does not prescribe a numeric threshold; organisations must define a documented policy and apply it consistently.

10. Reporting & Disclosure Mapping

The Corporate Standard does not operate in isolation. The following matrix maps its requirements to the four frameworks most commonly cited alongside it in corporate sustainability disclosures and regulatory submissions.

10.1 GHG Protocol ↔ ISO 14064-1

ISO 14064-1 (2018 revision) aligns closely with the Corporate Standard on boundary, scope, and calculation methodology. The principal differences are structural: ISO 14064-1 integrates directly with the ISO 14064-3 verification protocol, mandates a documented inventory management plan, and uses a six-category emissions classification (direct, indirect from imported energy, indirect from transportation, indirect from products used, indirect from products sold, other indirect) rather than the GHG Protocol’s three-scope framework. The classifications are reconcilable: an inventory built on the GHG Protocol can be presented under either framework with modest procedural additions. See ISO 14064-1 full mapping.

10.2 GHG Protocol ↔ GRI 305

GRI 305 (Emissions, 2016) explicitly adopts the GHG Protocol Corporate Standard for calculation methodology. An organisation preparing a GRI 305-aligned report using GHG Protocol calculation and AR6 GWP is methodologically aligned by construction. GRI 305 adds disclosure requirements around emission intensity ratios (Disclosure 305-4), reduction initiatives (305-5), and Scope 3 significance assessment that the Corporate Standard does not mandate. See GRI 305 full mapping.

10.3 GHG Protocol ↔ SBTi

The Science Based Targets initiative requires inventories to be GHG Protocol-aligned as a precondition for target validation. SBTi-validated targets use the GHG Protocol base year as the reference and apply the Standard’s recalculation rules. Companies setting near-term and long-term net-zero targets must demonstrate Scope 3 coverage under the SBTi Net-Zero Standard, with the Corporate Standard’s materiality assessment as the operative basis. See SBTi Net-Zero Standard mapping.

11. Industry Applicability & Sector Interpretation

The Corporate Standard is methodologically agnostic across sectors but its application varies materially. The following table summarises the Scope 1, 2, and 3 emphasis typical of nine major sectors and the principal interpretation issues each faces.

12. Common Reporting Errors & Audit Failures

The following scenarios represent the most common material errors identified during third-party verification of GHG inventories. Each is reproduced here with the protocol basis for non-compliance and the corrective treatment.

13. Audit Readiness Checklist

• ✔ Boundary approach (operational control / financial control / equity share) selected, documented, and applied consistently across the inventory.
• ✔ Scope 1 (all four source categories) disclosed with gas-level breakdown.
• ✔ Scope 2 location-based reported. Market-based reported where contractual instruments exist, with instrument retirement evidence retained.
• ✔ Scope 3 materiality assessment documented across all 15 categories. Material categories quantified; immaterial categories excluded with documented rationale.
• ✔ GWP version disclosed (AR6 recommended). All gases converted to CO₂e using the disclosed GWP basis.
• ✔ Gas-level disaggregation included: CO₂, CH₄, N₂O, applicable F-gases.
• ✔ Biogenic CO₂ disclosed separately as memo items, not aggregated into Scope 1 totals.
• ✔ Base year defined. Recalculation policy documented and applied to any structural changes since base year.
• ✔ Emission factor sources cited, with vintage and geography. Factor selection hierarchy applied consistently.
• ✔ Data quality tiering documented for material inventory items. Improvement plan in place where lower-tier data is used.
• ✔ Inventory management plan documented (per ISO 14064-1 if applicable).
• ✔ Year-on-year variance analysis prepared, reconciling structural change, methodology change, factor refresh, and actual emissions change.

14. Frequently Asked Questions