Managing transport emissions that everyone uses…and no-one really owns!
If Scope 3 Category 1 is uncomfortable, Categories 4 and 9 are awkward.
What are Scope 3 Category 4 and Category 9 transport emissions?
Scope 3 Category 4 and Category 9 transport emissions cover the greenhouse gas impact of moving goods through your value chain. Category 4 (upstream transportation and distribution) captures emissions from supplier-to-gate logistics, while Category 9 (downstream transportation and distribution) covers gate-to-customer movements. Under the GHG Protocol Corporate Value Chain Standard, reporting organisations must account for emissions from all third-party carriers, freight forwarders, and distribution centres used in both directions.
| Aspect | Category 4 (Upstream) | Category 9 (Downstream) |
|---|---|---|
| Boundary | Supplier to reporting company | Reporting company to end customer |
| Included activities | Inbound freight, third-party warehousing | Outbound freight, retail distribution, last-mile delivery |
| Common transport modes | Container shipping, road haulage, rail freight | Road delivery, parcel carriers, air freight |
| Typical data sources | Supplier invoices, freight forwarder reports | Carrier reports, 3PL data, distribution centre records |
| Calculation method | Distance-based (tonne-km) or spend-based | Distance-based (tonne-km) or spend-based |
| Key challenge | Supplier unwillingness to share freight data | Lack of visibility beyond first delivery point |
They sit in that familiar ESG grey area: emissions you rely on, influence indirectly, and are expected to report — but don’t directly control. Transport happens because your business exists, yet responsibility for its carbon footprint is fragmented across suppliers, carriers, contracts and routes that rarely line up neatly.
This playbook sets out how leading organisations approach Scope 3 Categories 4 and 9 — not as an exercise in logistics perfection, but as a manageable, defensible discipline that improves over time.
What Categories 4 & 9 Actually Cover
Category 4 captures upstream transportation and distribution — the movement of goods from suppliers to your operations. Category 9 covers downstream transportation and distribution — the movement of goods from your business to customers, retailers or end points not owned or controlled by you.
In theory, that sounds simple. In practice, transport emissions are scattered across freight forwarders, shipping lines, last-mile carriers and third-party logistics providers, each with their own data standards and priorities.
One supply chain manager described it neatly: “The emissions are everywhere, but the data is nowhere.”
Why Transport Emissions Are So Difficult to Pin Down
Transport emissions are defined by movement — distance, weight, mode, route, utilisation. That means data often lives in operational systems designed to move goods efficiently, not to explain carbon impact.
In many organisations, logistics data is optimised for cost and service levels. Carbon is an afterthought, if it’s captured at all.
We’ve seen teams attempt to reconstruct a year of transport emissions using invoices, shipment records and best guesses. The result is usually a heroic spreadsheet, a very tired analyst, and a number everyone agrees not to look at too closely.
The Reality of Estimates in Categories 4 & 9
Most organisations start with distance- or spend-based estimates for Categories 4 and 9. And, as with Category 1, that’s entirely reasonable.
Estimates provide coverage. They allow organisations to understand scale and direction. They surface which transport modes matter most — air freight rarely hides for long.
The risk comes when estimates are presented without context.
One logistics lead summed it up bluntly: “We know this isn’t precise, but we don’t know how wrong it is.” That uncertainty is what undermines confidence, not the use of estimates themselves.
When Carrier Data Complicates Things
As logistics providers begin supplying emissions data, a new challenge emerges.
Carrier-reported emissions often use different assumptions, allocation methods and boundaries. One provider reports well-to-wheel emissions. Another reports tank-to-wheel. A third reports something in between.
Without standardisation, organisations can end up stitching together numbers that look sophisticated but don’t quite add up.
More data arrives. Confidence doesn’t necessarily follow.
What Good Looks Like for Categories 4 & 9
Leading organisations take a pragmatic approach.
They start by establishing a clear baseline using consistent assumptions. They identify the transport modes, routes or regions that drive the majority of emissions. They focus engagement on the logistics partners that matter most, rather than attempting to extract perfect data from everyone.
One global manufacturer shared that once they focused on air freight lanes alone, they unlocked more insight in three months than they had in the previous two years.
Progress came from focus, not volume.
Clarifying Ownership Across the Organisation
Transport emissions sit at the crossroads of sustainability, supply chain, finance and operations — which makes ownership particularly easy to avoid.
Successful organisations are explicit. ESG defines the methodology. Supply chain teams provide operational insight. Finance ensures governance and consistency. Logistics providers supply data where available.
When those roles are clear, Categories 4 and 9 stop drifting between functions and start moving forward.
From Disclosure to Decision-Making
The turning point comes when transport emissions inform decisions.
That might mean reviewing air freight policies, re-evaluating distribution networks, or understanding the carbon impact of service-level commitments. The aim isn’t to eliminate trade-offs, but to make them visible.
A supply chain director put it simply: “Once we could see the carbon cost of speed, conversations changed.” That’s when Categories 4 and 9 start to matter.
What This Means for You
If You’re in Supply Chain or Logistics
Categories 4 and 9 don’t require you to become a carbon accountant. They require clarity.
A structured approach allows you to understand which routes, modes and decisions drive emissions, without drowning in data requests. Carbon becomes another operational lens — not a distraction, but a tool to support better network and service-level decisions.
If You’re an ESG or Sustainability Manager
Transport emissions are rarely perfect, but they can be credible.
This playbook approach gives you a defensible baseline, a clear improvement pathway, and a way to explain uncertainty without undermining trust. It shifts the conversation from “Is this exact?” to “Is this directionally right — and are we acting on it?”
If You’re a CFO or Finance Leader
Categories 4 and 9 often sit outside traditional financial controls — which is exactly why governance matters.
A structured methodology ensures the numbers you sign off are consistent, explainable and auditable. More importantly, it links emissions back to operational and commercial decisions, where oversight actually makes a difference.
If You’re a CSO or Board Sponsor
Transport emissions are visible, emotive and increasingly scrutinised.
A pragmatic, transparent approach shows stakeholders that the organisation understands where its logistics footprint sits, acknowledges uncertainty, and has a credible plan to improve over time. That combination builds confidence far more effectively than precision theatre.
What This Looks Like in Horizon ESG
Horizon ESG’s ESG reporting platform supports this journey by helping organisations establish consistent baselines, layer in carrier-specific data where it adds value, and track data quality over time. Emissions can be linked to routes, modes and partners, making transport a manageable part of the Scope 3 picture.
The Playbook Mindset
Scope 3 Categories 4 and 9 are uncomfortable because they expose the hidden mechanics of how goods actually move.
But they also reveal opportunity.
Organisations that approach transport emissions with focus, transparency and realism don’t just report better — they make smarter operational decisions.
And that’s the point. Book a demo to see how Horizon ESG can help.
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