Band 8.5 — Bar Chart: CO2 Emissions per Passenger-Kilometre by Transport Mode

The bar chart compares five modes of transport in terms of the carbon dioxide each emits per passenger for every kilometre travelled.

Overall, there are vast differences between the modes: flying is comfortably the most polluting way to travel, while the bicycle is virtually emission-free. Broadly speaking, the more collective the mode of transport, the smaller its footprint per person.

Domestic flights sit at the very top of the scale, generating 255 grams of CO2 per passenger-kilometre. A petrol car carrying a single occupant is the second-worst option at 170 grams, well over half as much again as the bus, which produces 95 grams. These three, then, dominate the upper end of the chart.

The remaining modes are dramatically cleaner. Rail travel emits just 35 grams per passenger-kilometre, roughly a seventh of the figure for flying and around a fifth of that for a solo car journey. Cycling, at a mere 5 grams, largely accounted for by manufacturing rather than actual use, produces around one-fiftieth as much as a domestic flight, making it far and away the greenest choice of the five.