Shipping emissions: compare fuels with the same voyage boundary
An ambition is not a shipment certificate
The IMO’s 2023 strategy describes greenhouse-gas ambitions for international shipping. A strategy, an agreed proposal, an adopted rule and a rule in force are different stages. This article uses the dated strategy for context and does not assert the present legal status of a later framework. Confirm applicable current requirements with the responsible authority and carrier.
Compare the same freight service
| Field | Keep comparable |
|---|---|
| Service | Cargo quantity, origin, destination and period |
| Activity | Voyage distance and allocation to the shipment |
| Fuel | Production route and source of the lifecycle factor |
| Boundary | Fuel production, delivery and ship operation included or excluded |
| Evidence | Measured activity, calculation method and verification scope |
| Claim | Physical service, allocation or certificate; what it actually covers |
Two fuels with the same name can come from different production routes. A ship’s direct exhaust figure also differs from a lifecycle estimate. Do not rank options using one tank-to-wake result and one well-to-wake result.
A fictional intensity calculation
Suppose a carrier assigns 12 tonnes of CO₂-equivalent to transporting 100 tonnes of cargo over 2,000 kilometres under a stated method. Dividing 12,000 kg by 200,000 tonne-kilometres gives 0.06 kg CO₂e per tonne-kilometre. This is a unit example, not a route benchmark. If a second quote excludes fuel production, the intensities cannot be compared without aligning their boundaries.
What to ask for with a quote
Ask for the period, factor source, allocation method and any separate certificate terms. Preserve exclusions next to the figure, including empty repositioning or other legs if omitted. A lower disclosed intensity can support a scoped comparison; it does not automatically establish compliance or a complete reduction across the supply chain.
Sources and scope
- IMO: 2023 greenhouse-gas strategy — A dated strategy and ambitions; not evidence that a later measure is currently binding.
Sources checked October 10, 2026. AI-assisted research and drafting. The examples, calculations and worksheets are Luminesca editorial work; they are not measured trials, first-hand reporting or an independent certification. Removed assertions about the current legal status of a proposed framework and universal fuel rankings. Report a specific correction with its source.