Airline industry could halve emissions by using existing planes more efficiently

Global aviation emissions could be cut by between 50 and 75% through simple changes using existing technology, according to Oxford University researchers.

A study published this week in Nature Communications Earth & Environment analysed more than 27 million commercial flights and suggests three strategies for boosting efficiency: fly only the most fuel-efficient aircraft; switch to all-economy layouts; and increase passenger loads. 

Doing this could drive average aviation emissions down from their current level of 84.4g of CO₂ per kilometre. Replacing all aircraft with the most efficient models – the Boeing 787-9 for long-haul and the Airbus A321neo for short- and medium-haul flights – would create fuel savings of 25 to 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,” says Dr Milan Klöwer from Oxford‘s Department of Physics. “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.”

Changing seating configurations could reduce emissions by 22 to 57% according to the researchers, as business and first-class seats are up to five times more CO₂ intense. And, finally, increasing aircraft passenger occupancy from the current level of 79% to 95% would cut emissions per kilometre by a further 16%. 

This would, of course, require huge investment and systemic changes. But the study also found that even simply flying the most efficient aircraft on already operating routes could cut emissions by 11%. 

“Efficiency-based policies have a great potential to curb aviation emissions and can be in airlines’ own economic interest,” said Stefan Gössling from Sweden’s Linnaeus University, the study's lead author. “But the reality is that many airlines continue to fly with old aircraft, low passenger occupancies and growing proportions of premium-class seating.” 

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