Scope 3 Category 4: Upstream Transport and Distribution Explained
Scope 3 Category 4: Upstream Transport and Distribution Explained
Scope 3 Category 4 covers transportation and distribution of goods and materials you purchase — from your suppliers to your facilities. It is one of the most commonly misunderstood Scope 3 categories, and one that many companies either omit or miscalculate. This guide explains what is included, what is excluded, and how to calculate it accurately for procurement questionnaire responses.
What Category 4 Covers
Category 4 includes: - Transport of goods you purchase from your suppliers to your own facilities (third-party logistics) - Transport between your own facilities (inbound inter-site logistics using third-party hauliers) - Warehousing energy at third-party logistics sites (optional)
Category 4 does not include: - Your own vehicle fleet transporting goods (that is Scope 1) - Outbound delivery of your products to customers (that is Category 9 — downstream transport) - Personal business travel (that is Category 6)
The boundary is: inbound goods, using vehicles you do not own or control.
Why Category 4 Matters for Manufacturers and Distributors
For a manufacturer importing raw materials or receiving JIT components by road freight, Category 4 can be the second or third largest emission source after electricity and process heat. A manufacturing company receiving 2,000 tonnes of steel annually by HGV from a supplier 200 km away:
- 2,000 tonnes x 200 km = 400,000 tonne-km
- At DEFRA 2023 HGV factor (0.065 kgCO2e/tonne-km for articulated HGV, 40t): 26 tCO2e
For air freight, the factor is dramatically higher: 0.602 kgCO2e/tonne-km for long-haul air — making a single air-freighted component delivery potentially larger than all road freight combined.
Emission Factors for Common Transport Modes (DEFRA 2023)
| Mode | Factor (kgCO2e/tonne-km) |
|---|---|
| ------ | -------------------------- |
| Articulated HGV (40t, diesel) | 0.065 |
| Rigid HGV (3.5–7.5t) | 0.161 |
| Van (under 3.5t, diesel) | 0.272 |
| Rail freight | 0.029 |
| Short-haul air freight | 1.264 |
| Long-haul air freight | 0.602 |
| Container ship (ocean) | 0.016 |
| Ro-Ro ferry | 0.128 |
How to Get the Data
The most accurate method: request annual freight summaries from your 3PL (third-party logistics) providers and couriers. Many provide tonne-km or freight-km data on request, and increasingly offer carbon calculation tools (DHL GoGreen, UPS My Choice for Business, DPD Carbon Calculator).
If detailed data is unavailable, use the DEFRA spend-based proxy: approximately 0.50 kgCO2e per £1 of UK domestic freight spend, or the equivalent in euros for European logistics spend. This is a rough estimate — use it only when tonne-km data cannot be obtained.
Is Category 4 Required for SME Questionnaire Responses?
For most SME supplier questionnaire responses (EcoVadis, CDP, SAP Ariba), Category 4 is optional or asked as "if material." Include it if transport is a significant part of your cost base. If you are a service business with no physical goods delivery, note "not applicable" in the Category 4 field.
For manufacturing and distribution companies supplying automotive, retail, or logistics buyers, Category 4 is frequently requested as a required field.
Generating Your Carbon Passport
DeCarbonOPS covers operational Scope 3 categories (WTT, waste, travel, commuting) for SME supplier questionnaire responses. For detailed Category 4 transport calculation, request freight summaries from your logistics providers and add the tonne-km data to your supplementary documentation. Your Carbon Passport covers the mandatory operational categories — add Category 4 data as supporting commentary in your questionnaire response.
Frequently Asked Questions
What is the difference between Scope 3 Category 4 and Category 9?
Category 4 covers upstream transport — goods moving toward your company (inbound: from your suppliers to your facilities). Category 9 covers downstream transport — goods moving away from your company (outbound: from your facilities to your customers or distributors). A distributor has both: Category 4 (receiving stock from manufacturers) and Category 9 (delivering to retailers or end customers). Your own vehicle fleet delivering goods is Scope 1, not Category 4 or 9.
How do I get tonne-km data from my freight providers?
Most large logistics providers (DHL, UPS, DB Schenker, Kuehne+Nagel, DPD, TNT/FedEx) offer carbon reporting tools or annual account summaries that include shipment distance and weight data. Request an annual freight summary from your account manager — ask specifically for total tonne-km by transport mode. If tonne-km data is unavailable, use freight weight (tonnes) and average distance (km) from shipping records to calculate tonne-km yourself.
Is Category 4 mandatory for all SME questionnaire responses?
No — for most SME questionnaire responses on platforms like EcoVadis, CDP, and SAP Ariba, Category 4 is optional or 'if material.' Service businesses with no physical goods deliveries note 'not applicable.' Manufacturing and distribution companies where inbound freight is a significant cost line should include Category 4. Automotive, retail, and logistics buyers frequently request it as a required field for goods-heavy supply chains.
What emission factor should I use for parcel delivery services like DHL or DPD?
Use the DEFRA 2023 factor for the relevant vehicle type: van under 3.5t diesel = 0.272 kgCO2e/tonne-km; rigid HGV 7.5–17t = 0.173 kgCO2e/tonne-km. If DHL or DPD provides a certified carbon figure in their account report (through their GoGreen or DPD Carbon Calculator programmes), use their certified figure — it is typically more accurate than the generic DEFRA proxy. Note the data source in your methodology statement.
How do I calculate Category 4 for air freight imports?
Air freight has the highest emission factor of any transport mode. DEFRA 2023 factors: short-haul air freight (under 3,700 km) = 1.264 kgCO2e/tonne-km; long-haul air freight = 0.602 kgCO2e/tonne-km. Example: 500 kg imported from China (approximately 9,000 km) = 0.5 tonnes x 9,000 km x 0.602 = 2,709 kgCO2e = 2.7 tCO2e for a single shipment. This underscores why sea freight (0.016 kgCO2e/tonne-km) is dramatically more carbon-efficient for high-volume imports.
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