Scope 3 emissions are notoriously tricky to navigate, and the category system doesn’t always make things easier. With 15 categories covering everything from raw material extraction to the end of a product’s life, it’s easy to lose track of what belongs where. Two categories that frequently cause confusion are Category 1 (purchased goods and services) and Category 4 (upstream transportation and distribution). They’re both upstream, they both involve suppliers, and yet they measure fundamentally different things. Getting them mixed up isn’t just a reporting headache — it can distort your emissions picture and throw off your reduction strategy entirely. Here’s how to tell them apart.
What each category actually measures
Category 1 covers the emissions embedded in everything your organization buys — the goods and services that go into your products or operations. Think raw materials, components, packaging, software subscriptions, office supplies, and professional services. The emissions being measured here are those that occurred during the production of those purchased items, not during their delivery to you. It’s about what was made, not how it got to you.
Category 4 is specifically about the movement of goods. It captures the emissions from transporting and distributing products upstream in your supply chain — meaning shipments that happen before those goods reach your facility. This includes freight by road, rail, sea, or air, as well as warehousing and third-party logistics operations that are part of getting materials or products to your door. If a truck drove it to you, Category 4 is likely where those emissions live.
The cleanest way to think about it: Category 1 is about the carbon cost of making things, and Category 4 is about the carbon cost of moving things. Both sit upstream, but they capture entirely separate activities in your supply chain.
Where the boundary between them lies
The boundary is actually more precise than it might seem. Under the GHG Protocol’s Corporate Value Chain Standard, Category 1 emissions end at the point of production — once a product has been manufactured, that’s where Category 1 stops. Category 4 then picks up the moment goods start moving toward you.
Where it gets genuinely tricky is with logistics services. If you pay a freight company to ship materials to your facility, those transportation emissions belong in Category 4. But if you’re purchasing a logistics service as part of your core operations (say, a third-party fulfillment provider that handles your outbound orders), that might fall under Category 1 as a purchased service. The key question is always: are you buying the production of something, or are you buying the transportation of something?
Another common grey area is Incoterms. If your supplier includes delivery costs in the purchase price and arranges the transport themselves, you may still need to account for those upstream transport emissions in Category 4 — they don’t disappear just because they’re bundled into an invoice. This is where many organizations accidentally underreport.
How data collection differs for each category
Collecting data for these two categories requires different approaches, and it’s worth understanding why before you start building your data collection process.
For Category 1, the most common method is spend-based estimation, where you apply emission factors to your procurement spend by category. This is practical when supplier-specific data isn’t available, though it’s less precise. A more accurate approach is the supplier-specific method, where you request actual emissions data from your suppliers — increasingly common for large organizations working toward Science Based Targets (SBTi) alignment or CSRD reporting. Life cycle assessment (LCA) data can also be used when available.
Category 4 data collection tends to be more activity-based. You’re typically working with freight data: distances traveled, transport modes, and cargo weights. Freight carriers and logistics providers are increasingly able to supply this data, especially as reporting expectations grow. If you don’t have direct access to transport data, distance-based or spend-based estimates can fill the gap, though they’re less precise.
The practical difference is that Category 1 often requires supplier engagement and procurement data, while Category 4 requires logistics data and freight records. They tap into different parts of your organization, which means your data collection process needs to involve different teams.
Common reporting mistakes across both categories
Even experienced sustainability teams run into pitfalls when reporting these two categories. A few show up more often than others.
- Double-counting transport within Category 1: Some emission factors for purchased goods already include upstream transport. If you then also report that transport in Category 4, you’re counting it twice. Always check whether your Category 1 emission factors are cradle-to-gate (which typically include transport) or gate-to-gate.
- Omitting supplier-arranged transport from Category 4: When suppliers handle and pay for delivery, organizations often assume it’s the supplier’s problem to report. But if those goods are being transported to your facility, the GHG Protocol expects you to account for those emissions in your Category 4 inventory.
- Using spend-based estimates where activity data is available: Spend-based methods are a useful starting point, but they can significantly overestimate or underestimate actual emissions depending on your industry and supplier mix. When logistics data or supplier-specific data is accessible, it’s worth using it.
- Treating capital goods as Category 1: Purchased capital goods — machinery, equipment, buildings — have their own home in Category 2. Mixing them into Category 1 inflates those figures and misrepresents where your supply chain emissions actually sit.
What ties these mistakes together is a lack of clarity about where one category ends and another begins. Getting the boundaries right from the start saves a lot of rework later, especially if you’re preparing for external assurance or CDP disclosure.
How to prioritize reduction efforts in each category
Knowing the difference between these categories also shapes where you focus your decarbonization efforts, and the levers available to you are quite different.
For Category 1, reduction typically comes through supplier engagement and procurement decisions. This means working with suppliers to understand and reduce the emissions embedded in their products, shifting to lower-carbon materials or alternatives, and using your purchasing power to favor suppliers with credible climate commitments. It’s a longer-term effort, but it’s where the biggest emissions reductions often live for manufacturing and product-heavy organizations.
Category 4 reductions are more operational and often faster to act on. Consolidating shipments, shifting to lower-emission transport modes (rail over road, sea over air), optimizing routes, and working with logistics providers who use cleaner fleets are all practical steps. If you have influence over Incoterms or can shift freight decisions upstream, that creates additional room to move.
The broader point is that Category 1 tends to require supply chain transformation over time, while Category 4 offers more near-term operational wins. A smart reduction strategy addresses both, but knowing which is which helps you sequence your efforts and set realistic targets.
Ready to make sense of your scope 3 emissions?
Scope 3 reporting is detailed work, and the line between categories like these can get blurry fast. Whether you need someone to build out your data collection process, prepare your emissions inventory for CSRD reporting, or develop a supplier engagement strategy for Category 1, the right expertise makes a real difference.
At Dazzle, we connect organizations with pre-screened scope 3 specialists and sustainability reporting experts who’ve done this work before. You can be matched with the right person for your specific challenge and start working together within 48 hours. No lengthy procurement processes, no generalist advice — just the right expert, when you need them. Reach out to our team and let’s figure out the best fit for your project.
Looking for hands-on support with this? See how our Scope 3 consultants help companies build inventories that hold up to scrutiny.
