CO₂ estimates for ocean shipments

Ocean shipments now carry a CO₂ emissions figure alongside the ETA in the transport details, the way air shipments already did.

It’s calculated from the great-circle distance between the shipment’s tracked ports and the cargo weight, using distance-banded emission factors — short-sea legs are less fuel-efficient per tonne-kilometre than deep-sea ones. Multi-leg routes are priced leg by leg and summed, so a transshipment isn’t averaged away into a single band.

Shipments tracked before this existed have been backfilled.

The figure is shown in tonnes (🌍 1.50 tonnes) on the shipment page, labelled as an estimate, and is available as an optional column on the shipments list.

FAQ #

Is this figure accurate enough to report? #

It is an estimate, and it is labelled as one. It is derived from distance and cargo weight rather than from the vessel’s actual fuel burn, which no carrier publishes per container. Treat it as a good-faith order of magnitude for internal reporting, not as an audited figure.

Why does a short leg emit more per tonne-kilometre than a long one? #

Short-sea vessels are smaller and spend proportionally more of the voyage manoeuvring, at berth and at reduced speed. The emission factors are banded by distance to reflect that rather than applying one average to every leg.

Does a transshipment get counted properly? #

Yes. Multi-leg routes are calculated leg by leg and summed, so each leg gets the band that matches its own length instead of the whole journey being averaged into one.