CE Delft was commissioned by Greenpeace to study which KLM flights are the most polluting, in both absolute and relative terms. In this study, the greatest polluter is defined as the one with the greatest impact on the climate, taking into account both CO2 and non-CO2 climate effects over the entire route of a flight from the Netherlands to the destination airport.
The KLM flights that contribute the most to pollution are those to its long-haul destinations. A flight to Buenos Aires, which is the furthest long-haul destination that can be reached directly, causes the most pollution, both in terms of the flight itself (1,281 tonnes of CO2 equivalent) and per passenger (3.75 tonnes of CO2 equivalent per Economy Class passenger). By way of comparison, the climate impact of this flight per passenger is roughly equal to the CO2 emissions produced in one year by an average Dutch household for food and drink, driving a car or heating their home.
Short-haul flights have a much smaller impact on the climate. The climate impact of a flight from Schiphol to Buenos Aires is 92 times greater than that of a flight to Paris. In relative terms, short-haul and long-haul flights have approximately the same climate impact (around 0.25 kg CO2 equivalent per passenger kilometre).