ISO 14083 — the standard shippers' sustainability teams audit against — computes freight emissions as transport activity × emission intensity. Activity is tonne-kilometres: the cargo's mass times the distance it moved. Intensity is kilograms of CO2e per tonne-km, well-to-wheel — the fuel's whole life, not just what left the exhaust. Multiply, and that is the whole method. Everything hard about freight emissions lives in WHERE THE INTENSITY CAME FROM, which is why this page names its source and date on every answer.
The defaults here are the GLEC Framework v3.2 published values — the factor set ISO 14083 itself grew out of. The framework's own hierarchy is blunt: primary data from your carrier beats a modelled default every time. That is why the override field exists and why the answer brags when you use it. A forwarder who asks their airline for a lane intensity once a year produces better numbers than one who owns the fanciest default table.
For a Hong Kong SME forwarder this number is commercial, not ceremonial. European and increasingly mainland consignees write per-shipment CO2e into vendor requirements; the forwarder who cannot answer drops off the tender list before price is discussed. The magnitudes are also a sales tool in themselves: the same 8 tonnes HKG→Europe emits roughly fifty times more by air than by sea — a customer with flexible cargo and a deadline three weeks out is a modal-shift conversation, and this page prices it in carbon the way your quote prices it in dollars.
GLEC came first: an industry methodology from the Smart Freight Centre for calculating logistics emissions consistently across modes. ISO 14083 (published 2023) turned that approach into an international standard. In practice they agree on the method — tonne-km × well-to-wheel intensity — and GLEC v3 publishes the default factor tables people actually plug in. If a customer asks for "ISO 14083-aligned" numbers, a calculation like this one, with the factor source named, is the shape of the answer.
Allocation. A passenger aircraft burns its fuel mostly to carry people, seats and the airframe; the GLEC mass-based allocation hands the belly cargo its share of a much less freight-efficient flight, and modern freighters carry far more freight per litre. Under other allocation conventions belly can come out lower — which is exactly why the factor's source matters more than the factor, and why two honest parties can quote different numbers for the same pallet until they agree whose table governs.
Yes — with its passport attached. State the method (ISO 14083 activity-based), the factor and its source and date ("GLEC v3.2 default, WTW, retrieved …"), and the distance basis (GCD or routed). A labelled estimate builds trust; a bare number invites an audit you cannot answer. And when a customer's sustainability team eventually asks for carrier-specific data, that request is your reason to ask your carriers — the override field is waiting.
No. The GLEC well-to-wheel defaults count greenhouse gases; the additional warming from contrails and NOx at altitude — radiative forcing — is reported separately where a regime requires it, typically as a multiplier that can roughly double the air number. Corporate reporting under some protocols wants it, others exclude it. The honest move is the same as everywhere else on this page: say which convention the number follows, and never mix the two in one comparison.
Cargo-Stack reads the enquiry, prices it against your own rates, and drafts the quote — with this arithmetic underneath it. Same maths, no retyping.
Try it on a real enquiry