GHG Protocol Scope 3 Standard revision: what is changing and how to prepare
The GHG Protocol is revising its Scope 3 Standard for the first time since 2011. The draft proposals published so far would require companies to report at least 95% of their required Scope 3 emissions, disclose how much of the total rests on each type of data, and stop allocating a diversified supplier's company-wide emissions to their purchases. Nothing is final yet: under the current plan a consolidated draft goes to public consultation in 2027 and the revised standard is due in late 2028. The direction, though, is clear enough to start preparing supplier data now.
Why the Scope 3 Standard is being revised
The Corporate Value Chain (Scope 3) Standard was published in 2011. Since then Scope 3 has moved from a voluntary extra to a disclosure that regulators and investors expect: ESRS E1 and IFRS S2 both call for Scope 3 information, and target-setting bodies such as the SBTi set Scope 3 boundary rules of their own. Inconsistent boundaries, heavy reliance on spend-based estimates and little transparency about data quality have made Scope 3 figures hard to compare between companies.
The GHG Protocol surveyed stakeholders between November 2022 and March 2023, started formal standard development in 2024 and announced a partnership with ISO in September 2025. In March 2026 it published a Phase 1 progress update describing draft proposals on data quality, boundaries and investments.
The timeline: what is planned and when
Scope 3 is no longer on a separate track. Under the GHG Protocol's standard development plan of July 2026, the Scope 3 requirements will be folded into a consolidated Corporate Standard (version 3.0), developed jointly with ISO. The plan estimates:
- Q2 2027 — consolidated draft standard published for public consultation;
- Q4 2028 — revised standard published.
The plan gives no effective date and says the timeline may change. Updated Scope 3 guidance is to follow the standard. Until the revised standard is published, the 2011 Scope 3 Standard remains the one to report against.
The main draft proposals
Everything below comes from working drafts that the GHG Protocol's Independent Standards Board had not approved when they were published. They show the likely direction, not final rules.
1. A 95% minimum boundary
The draft says companies "shall account for and report at least 95% of total required scope 3 emissions". Exclusions, including de minimis items, would be capped at 5%, and companies would quantify their total required Scope 3 every year — a hotspot analysis is acceptable — to show they stay within the cap. Exclusions would be disclosed and justified using a standard notation, and required and optional Scope 3 emissions would be reported separately. Downstream emissions of intermediate products whose end use is unknown could still be excluded outside the 5% cap.
2. Disclosure by data type
Companies would split Scope 3 emissions into tiers by the type of data behind them, from supplier-specific data down to estimates, with an "unclassified" tier for the rest. Two classification options were still under discussion. The draft also recommends setting goals for the share of specific or primary data, tracking metrics such as the percentage of suppliers providing specific data, and setting year-on-year data quality improvement targets.
3. Limits on allocating supplier totals
Many companies take a supplier's company-wide emissions and allocate a share to their purchases, often by revenue. The draft says corporate-level allocation "shall not be used" for value chain partners, except where the partner is "homogeneous" — broadly, a company whose activities are similar enough that an average is meaningful. Definitions were still pending. For diversified suppliers, this points towards product-level or activity-level data.
4. Emission factors and verification
The draft recommends emission factors with no more than 5% cut-off or exclusions, and regional factors that account for imports and exports. Companies that verify some or all of their Scope 3 emissions would disclose whether it is fully, partially or not verified. Whether verification becomes mandatory sits with the Corporate Standard working group.
5. Category 15 and a new Category 16
Category 15 would be narrowed to investments — financed emissions — with all investments required, investee Scope 1, 2 and 3 in the boundary, and the equity share calculation including debt in the denominator, in line with PCAF. A proposed Category 16, "other value chain activities", would cover facilitated activities such as brokerage, underwriting and insurance, mostly on an optional basis. Our financed emissions guide explains how PCAF treats these today.
What it means for supplier engagement
Taken together, the proposals reward companies that already know where their Scope 3 comes from and what each number rests on. Three practical consequences stand out:
- Completeness becomes measurable. A 95% threshold needs a full screening of every category each year, not only the categories you have chosen to report.
- Data type becomes visible. If the split between supplier-specific, average and spend-based data is disclosed, readers will see how much of your Scope 3 is estimated — and whether that share is falling.
- Revenue allocation weakens. For diversified suppliers you will need product carbon footprints or activity data for the items you buy, not just their company total.
How to prepare now
- Screen all 15 categories. Run a hotspot estimate for every category, record any exclusions with a reason and an estimated size, and check they would sit within 5%. Our Scope 1, 2 and 3 explainer lists the categories.
- Tag every Scope 3 line by data type. Record whether each figure uses supplier-specific, average-data or spend-based inputs, so you can report the split if it becomes required.
- Set a supplier-specific data goal. Pick the suppliers behind most of Category 1 and set a target for the share of emissions they cover with their own data. The steps are in our supplier engagement guide.
- Ask diversified suppliers for product data. Request cradle-to-gate footprints for the products you buy, rather than relying on revenue allocation of their totals.
- Keep evidence and versions. Record the emission factor source and version behind every number and keep an audit trail, so verification status can be stated with confidence.
- Plan to comment. The GHG Protocol has asked stakeholders to hold feedback until the public consultation opens, currently estimated for Q2 2027.
EKOTRACE already records the data type, emission factor version and approval history for each activity, and its supplier portal lets suppliers report emissions and product footprints that you review before they replace spend-based estimates. See how it fits a full GHG inventory.
Frequently asked questions
Is the GHG Protocol Scope 3 Standard changing?
Yes. The GHG Protocol is revising it alongside the Corporate Standard, jointly with ISO. Under its July 2026 plan, a consolidated draft is expected for public consultation in Q2 2027 and the revised standard in Q4 2028. Until then, the 2011 Scope 3 Standard applies.
What is the proposed 95% rule for Scope 3?
A draft requirement that companies report at least 95% of their total required Scope 3 emissions, with exclusions, including de minimis items, capped at 5% and disclosed with a justification. It is a proposal and could change.
What is Scope 3 Category 16?
A proposed new category, "other value chain activities", for facilitated activities from which a company earns income without buying, selling or owning the activity, such as brokerage, underwriting and insurance. Most of it would be optional.
Should we wait for the final standard before improving Scope 3 data?
No. Screening every category, tagging data by type and collecting supplier-specific data are good practice under the current standard and already help with ESRS, IFRS S2 and SBTi requirements. They also put you in a position to adopt the revised rules quickly.