Transport
‘Ban private jets now!’
A hundred climate activists block private jets at biggest business aviation sales event in Europe, protesting luxury mega-polluters.
24 May 2023
Main image: The study shows that replacing all aircraft with the most efficient models – including the Boeing 787-9 for all long-haul flights – would result in fuel savings of 25-28%
A new study co-led by the University of Oxford has found that, by combining three strategies to boost efficiency, global aviation emissions could be reduced by 50-75%.
The reduction would require only the most fuel-efficient aircraft to be flown, all-economy layouts on flights and increased passenger loads.
Crucially, the study shows that around a 11% reduction in global aviation emissions is achievable immediately, by using the most efficient aircraft that airlines already have more strategically on routes they already fly.
Published today (07 January) in Nature Communications Earth & Environment, the researchers analysed more than 27 million commercial flights in 2023, covering 26,000 city pairs and nearly 3.5 billion passengers.
This revealed enormous variability in emissions efficiency, with some routes producing nearly 900 grams of CO₂ per kilometre for each paying passenger – almost 30 times higher than the most efficient, at around 30 grams of CO₂ per kilometre.
‘Our results clearly show that efficiency-focused policy could swiftly reduce aviation emissions by more than half, without reducing flight numbers or waiting for future fuels. These are tools that we can use right now.’
DR MILAN KLÖWER
Co-author, Department of Physics, University of Oxford
Globally, average aviation emissions were 84.4 grams of CO₂ per kilometre for each paying passenger in 2023.
The study identifies three practical levers to reduce this figure: operating only the most fuel-efficient aircraft, removing premium-class seating to carry more passengers and raising passenger loads to 95%.
Aircraft model alone was found to make a significant difference, with emissions ranging from 60–360 gram CO₂ per kilometre for each passenger.
According to the analysis, replacing all aircraft with the most efficient models – the Boeing 787-9 (long-haul) and the Airbus A321neo (short- and medium-haul) – would result in fuel savings of 25-28%.
‘While economically and practically unfeasible to replace all older aircraft short term, this analysis shows the potential more efficient aircraft have in comparison to other efficiency gains. Realistically, this would be a long-term transition – one that could be promoted by policies that reward efficiency, so that the most efficient aircraft are favoured whenever replacement decisions are made.’
DR MILAN KLÖWER
Co-author, Department of Physics, University of Oxford
Seating configurations also matter, since business and first-class seats are up to five times more CO₂-intense than economy class seats.
The researchers found that increasing passenger numbers to the maximum seating configuration for the most efficient aircraft would further reduce emissions by 22-57%.
In 2023, aircraft passenger occupancy ranged from 20% to 100%, with an average of 79%. According to the analysis, increasing average occupancy to 95% would further reduce emissions by 16%.
If these three measures were applied globally, the study estimates that emissions could be reduced by between 50% and 75% – though this full reduction would require systemic changes.
The analysis found that airlines could reduce emissions by around 11% right now by flying their most efficient aircraft on routes where they already operate.
The researchers suggest that efficiency improvements could be promoted using policy tools and market-based measures, such as emissions ratings for airlines, adjusted landing fees based on aircraft performance and carbon intensity caps – drawing parallels to standards used in sectors like household appliances and vehicles.
‘Efficiency-based policies have a great potential to curb aviation emissions, and can be in airlines’ own economic interest. But the reality is that many airlines continue to fly with old aircraft, low passenger occupancies, and growing proportions of premium-class seating.’
PROFESSOR STEFAN GÖSSLING
Lead author, Linnaeus University
The study was based on data from Airline Data, the International Civil Aviation Organization and the International Air Transport Association.
This showed that the regions with the most inefficient flights were Africa, Oceania, the Middle East, Central Asia and North America.
The regions with the most efficient flights were Brazil, India and Southeast Asia.
The study also involved researchers from atmosfair providing data and the Munich University of Applied Sciences.
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