ISO Compliance Insights & Best Practices
CART
ISO Compliance Insights & Best Practices
Scope 3 emissions are all the indirect greenhouse gas emissions in a company’s value chain that are not covered by its electricity purchases or its own operations, and for many organizations they make up the largest share of the carbon footprint. They are also the hardest to measure, because the data sits with suppliers, customers and other third parties. This guide explains the 15 GHG Protocol categories, how to decide which ones matter to you, where to get data, and how to avoid the mistakes that weaken a report.
The Greenhouse Gas Protocol divides a company’s emissions into three scopes. Scope 1 covers direct emissions from sources the company owns or controls. Scope 2 covers indirect emissions from purchased energy. Scope 3 covers everything else that occurs in the value chain, upstream and downstream. The GHG Protocol Corporate Value Chain (Scope 3) Accounting and Reporting Standard, published in 2011, is the reference used by most reporting frameworks. Its full text is available from the GHG Protocol website.
The standard requires companies to report total scope 3 emissions separately by category, to list the categories or activities excluded with a justification, and to disclose the data types, methods and the share of emissions calculated from supplier-provided data. That means the report is judged not only on the number but on how transparent the reasoning is.
The standard defines 15 categories, eight upstream and seven downstream.
| Direction | Category | Typical example |
|---|---|---|
| Upstream | 1. Purchased goods and services | Raw materials, cloud services, packaging |
| Upstream | 2. Capital goods | Machinery, buildings, vehicles bought |
| Upstream | 3. Fuel and energy-related activities | Extraction and transmission of fuels and power |
| Upstream | 4. Upstream transportation and distribution | Inbound freight paid for by the company |
| Upstream | 5. Waste generated in operations | Third-party waste treatment |
| Upstream | 6. Business travel | Flights, rail, hotels |
| Upstream | 7. Employee commuting | Staff travel to work |
| Upstream | 8. Upstream leased assets | Leased offices or equipment |
| Downstream | 9. Downstream transportation and distribution | Outbound freight not paid for by the company |
| Downstream | 10. Processing of sold products | Intermediate goods processed by customers |
| Downstream | 11. Use of sold products | Energy used by products in service |
| Downstream | 12. End-of-life treatment of sold products | Disposal and recycling |
| Downstream | 13. Downstream leased assets | Assets the company leases to others |
| Downstream | 14. Franchises | Franchisee operations |
| Downstream | 15. Investments | Emissions of investee companies |
The GHG Protocol has begun revising the standard. Its March 2026 progress update says a complete draft for public consultation is forthcoming, and describes proposals that remain subject to change. Until a revised standard is published, keep reporting against the version you have, and watch the GHG Protocol website for consultations that may affect your categories.
Nobody calculates all 15 categories in detail on the first attempt. The standard expects you to account for all emissions, but it lets you set priorities through screening, and to document exclusions with reasons based on relevance and materiality. A sensible screening exercise takes four steps.
This record is the core of your defense when an assurance provider or investor asks why a category was left out. It is also the input to a double materiality assessment if you report under a regime that requires one.
Data quality for scope 3 emissions improves in steps. Most organizations begin with spend-based estimates, which multiply money spent by an emission factor for the sector. These are fast and cheap but coarse. The next step is activity-based data, such as tonne-kilometres of freight or kilograms of material, multiplied by a suitable factor. The best data comes from suppliers directly: product-specific or facility-specific figures. The GHG Protocol asks you to disclose the percentage of emissions calculated from supplier-provided data, so track it from the start.
Supplier engagement is where most programs slow down. Start with the suppliers that represent most of your spend or your estimated footprint, and send a short, clear request instead of a long questionnaire. Explain why you need the data, give a deadline, offer a template, and say how the answers will be used. Accept estimates at first, and ask for better data over successive years. Keep a log of who responded, so you can follow up and report the supplier-provided share honestly.
The following figures are hypothetical and are for illustration only. A mid-sized furniture maker screens its footprint. Purchased goods (timber, steel, foam, packaging) come to roughly 58% of the estimate. Downstream transport comes to 9%, use of sold products is negligible because furniture uses no energy, and end-of-life treatment is 7%. Business travel and commuting together are under 4%. Fuel and energy-related activities add a few percent.
The screening leads to clear decisions. The company will calculate purchased goods using activity data for the three largest material groups and supplier data for its top ten suppliers. It will estimate transport and end-of-life from freight and waste data, report use of sold products as not relevant with a written reason, and include travel and commuting using simple methods. Priorities for data improvement are then obvious, and the effort is concentrated where the emissions are.
Measuring scope 3 emissions is only useful if it changes decisions. Once you know the hotspots, engage the suppliers behind the largest ones, ask them for data and reduction plans, and consider procurement criteria that reward lower-carbon options. Redesign products to use less material or energy in use. Set targets that are meaningful for your business, and check any external target framework’s own rules on scope 3 before you commit. Link the results to your ESG KPIs so progress is tracked and reported, and to ESG governance so that someone senior owns the outcome.
Where scope 3 emissions are disclosed, they are increasingly read alongside other sustainability information and subject to assurance. Keep a methodology document, a calculation file that links each figure to its source, the emission factors used and the screening record. Review our overview of ESG reporting for the wider context, and confirm what your jurisdiction and your investors expect. Disclosure rules are moving, so check the current requirements that apply to your organization. Be careful with claims, and see our guide to greenwashing for what not to say.
A credible scope 3 program relies on written policies, a methodology, data collection templates, supplier questionnaires and a reporting pack. The ESG Toolkit provides templates that you can adapt to your organization. Whichever documents you use, keep the screening decisions, factors and sources easy to audit.
That depends on the rules that apply to you. The GHG Protocol standard is voluntary in itself, but regulations, stock exchanges, customers and investors may require disclosure. Check the requirements for your jurisdiction and sector.
The standard expects you to account for all relevant emissions and to list any exclusions with a justification. Categories that do not apply can be excluded with a documented reason.
Upstream emissions arise from goods and services you buy, and downstream emissions arise from what happens to your products after you sell them. Categories 1 to 8 are upstream, and 9 to 15 are downstream.
Yes, as a starting point, provided you disclose the method. Aim to replace spend-based estimates with activity data or supplier data in the categories that matter most.
Yes, the GHG Protocol has begun revising it, and the March 2026 update says a draft for consultation is forthcoming. Until a revised version is published, follow the current standard and monitor the consultation.
September 30, 2026
