Emissions intensity and total emissions: two different questions

Name the numerator and denominator

An intensity measure divides emissions by an activity such as passenger-kilometres, seat-kilometres or tonne-kilometres. These denominators describe different things. Passenger-kilometres count occupied traffic, while seat-kilometres count offered capacity. State the gas, unit, activity and accounting boundary before comparing two numbers.

Work through a fictional example

Suppose a hypothetical operation emits 80 tonnes of CO₂ for one million passenger-kilometres: its intensity is 80 grams per passenger-kilometre. If activity becomes 1.2 million and CO₂ becomes 90 tonnes, intensity is 75 grams. Intensity falls 6.25%, while the total rises 12.5%. These numbers illustrate arithmetic and are not measurements of an airline.

Keep climate scope visible

CO₂, CO₂-equivalent and a lifecycle fuel comparison are not interchangeable labels. Non-CO₂ effects and upstream processes require their own defined method and assumptions. A figure for fuel combustion cannot silently become a full climate footprint. Check which processes the source actually includes and how cargo or cabin classes are allocated.

Read progress on two axes

Ask both whether the service became less emission-intensive and whether the absolute total changed. Use the same period and method, and separate a reported outcome from a target. If data or allocation changed, that can alter a comparison even without a physical change in the aircraft. Keep the underlying source and review date with the result.

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