Key Points
- Scope 3 typically represents 70% to 90% of a company's total greenhouse gas footprint, dwarfing Scope 1 and Scope 2 combined.
- ESRS E1 paragraph 44 requires disclosure of gross Scope 3 emissions in metric tonnes of CO2 equivalent, broken down by significant category.
- The GHG Protocol defines fifteen mutually exclusive categories spanning purchased goods, transportation, employee commuting, use of sold products, and end-of-life treatment.
- EFRAG's November 2025 amended ESRS drafts preserve the Scope 3 requirement but allow greater reliance on estimates where supplier-specific data is unavailable.
What is Scope 3 Emissions?
The GHG Protocol splits a company's greenhouse gas footprint into three scopes. Scope 1 covers direct emissions from owned sources (boilers, fleet vehicles). Scope 2 covers indirect emissions from purchased electricity or heat. Scope 3 captures everything else in the value chain: purchased goods and services (category 1), upstream transportation (category 4), business travel (category 6), use of sold products (category 11), and eleven further categories. ESRS E1.44 requires entities reporting under the CSRD to disclose gross Scope 3 emissions by significant category, stated in metric tonnes of CO2 equivalent. The standard references the GHG Protocol's methodology directly and expects the entity to explain which categories it included, which calculation approach it applied (supplier-specific data, spend-based estimates, or hybrid methods), and what percentage of Scope 3 totals relies on primary data from suppliers (ESRS E1 AR 46(g)).
For most manufacturers and retailers, Scope 3 is the dominant share of total emissions. That makes it the category with the largest data gap, because the entity depends on suppliers, customers, and logistics partners for source information it does not control.
Worked example: Rossi Alimentari S.p.A.
Client: Italian food production company, FY 2025, revenue EUR 67M, IFRS reporter, 480 employees. Rossi is a Wave 2 CSRD entity (reporting deferred to FY 2027 by the stop-the-clock directive) but has elected to calculate Scope 3 voluntarily in preparation.
Step 1 — Identify significant Scope 3 categories
Rossi maps its value chain. Upstream, the two largest emission sources are purchased agricultural raw materials (category 1) and inbound logistics from suppliers across southern Europe (category 4). Downstream, the cold-chain distribution of finished goods to retail customers (category 9) and end-of-life treatment of packaging (category 12) are significant. The team screens all fifteen categories and classifies four as significant based on spend analysis and sector benchmarks from CDP.
Step 2 — Collect data and select calculation methods
For category 1 (purchased goods), Rossi obtains supplier-specific emission factors from its three largest raw material suppliers, covering 58% of procurement spend. The remaining 42% uses spend-based emission factors from the EXIOBASE database. For category 4 (upstream transport), Rossi uses distance-based calculations with emission factors from DEFRA 2025 conversion tables. Categories 9 and 12 rely on average-data methods.
Step 3 — Calculate and aggregate
Category 1 produces 18,400 tonnes CO2e. Category 4 produces 3,200 tonnes CO2e. Category 9 produces 5,100 tonnes CO2e. Category 12 produces 1,800 tonnes CO2e. Total Scope 3: 28,500 tonnes CO2e. Rossi's Scope 1 and 2 emissions total 4,600 tonnes CO2e, confirming that Scope 3 represents 86% of its carbon footprint.
Step 4 — Disclose under ESRS E1.44
Rossi prepares the E1-6 disclosure table in its sustainability statement, presenting gross Scope 1, Scope 2 (location-based and market-based), and Scope 3 separately. The Scope 3 breakdown shows each significant category with its tonnage and calculation method. A narrative note explains that 58% of category 1 emissions use supplier-specific data and identifies planned actions to increase primary data coverage to 75% by FY 2028.
Conclusion: Rossi's Scope 3 inventory of 28,500 tonnes CO2e across four significant categories is defensible because each category uses a documented calculation method, estimation uncertainty is disclosed, and the primary-data coverage percentage is traceable to supplier records.
Why it matters in practice
- Entities frequently report a single aggregated Scope 3 figure without breaking it down by category or disclosing which categories were included. ESRS E1.44 requires disclosure of gross Scope 3 emissions by significant category. An undifferentiated total gives the assurance provider no basis to evaluate completeness and prevents users from assessing where the real emission exposure sits.
- Teams apply spend-based emission factors to the entire Scope 3 inventory without attempting to obtain supplier-specific data for material categories. ESRS E1 AR 46(g) expects the entity to disclose the percentage of Scope 3 emissions calculated using primary data. A 0% primary-data figure signals to reviewers that the entity has not engaged its supply chain, and it widens the estimation uncertainty band to a point where the reported figure may not be meaningful for decision-making.
Scope 3 vs. Scope 1 and Scope 2
| Dimension | Scope 3 | Scope 1 and Scope 2 |
|---|---|---|
| Boundary | Upstream and downstream value chain (suppliers, logistics, customers, end-of-life) | Owned or controlled operations (Scope 1) and purchased energy (Scope 2) |
| Data control | Entity depends on third parties for source data; estimation is common | Entity controls the source data (fuel invoices, electricity meters) |
| Typical share of total footprint | 70%–90% for most manufacturers and retailers | 10%–30%, sometimes less |
| Calculation methods | Supplier-specific, spend-based, distance-based, average-data (GHG Protocol chapter 7) | Direct measurement or activity-based calculation from internal records |
| Assurance difficulty | Higher uncertainty bands; assurance providers frequently flag estimation limitations | Lower uncertainty; primary data is verifiable against internal systems |
The distinction matters on engagements because assurance providers assess Scope 3 estimation uncertainty separately from Scope 1 and 2. A limited assurance conclusion that treats all three scopes identically misses the fact that Scope 3 figures often carry uncertainty bands of 20% to 40%, while Scope 1 figures can be verified to single-digit precision from energy invoices.
Related terms
Frequently asked questions
How do I calculate Scope 3 emissions when suppliers won't share data?
Use the GHG Protocol's spend-based method as a starting point: multiply procurement spend per supplier by the relevant emission factor from a recognised database (EXIOBASE, DEFRA, EPA). ESRS E1 AR 46 permits estimates where supplier-specific data is unavailable without undue cost or effort. Document the emission factor source, the base year, and the limitations of the approach. Over successive reporting periods, prioritise obtaining primary data from the suppliers that represent the largest share of your Scope 3 footprint.
Does Scope 3 apply to companies below the revised CSRD thresholds?
Not as a mandatory ESRS disclosure. The Omnibus I directive (published 26 February 2026) restricts the CSRD to companies with 1,000 or more employees and net turnover above EUR 450M. Companies below those thresholds have no ESRS E1 reporting obligation. Voluntary Scope 3 reporting under the GHG Protocol or CDP remains common, and value chain partners of in-scope companies may face data requests regardless of their own reporting status.
When should I update my Scope 3 inventory?
Recalculate annually at each reporting date. ESRS 1.56 requires the entity to update its materiality assessment, and emission factors, supplier data, and business activities shift year to year. If a material change occurs mid-year (an acquisition that adds a new supply chain, for instance), reassess whether additional Scope 3 categories have become significant rather than waiting for the annual cycle.