Research shows aviation emissions reductions possible using today’s aircraft
A new study published in Communications Earth & Environment, a sibling publication to the internationally respected journal Nature, reports that large reductions in aviation carbon dioxide emissions could be achieved by improving how today’s aircraft are used, without waiting for new fuels or radically different aircraft.
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The paper “Large carbon dioxide emissions avoidance potential in improved commercial air transport efficiency”, analyses data from roughly 27.5m commercial flights worldwide in 2023, making it one of the most detailed examinations of aviation efficiency to date.
The researchers, led by Stefan Gössling of Linnaeus University in Sweden, examined how much CO₂ is emitted per revenue passenger kilometre, a standard measure that combines passenger numbers with distance flown.
According to the Nature study, the results reveal striking differences in efficiency across the global air transport system. Some routes and aircraft emit several times more CO₂ per passenger than others, even when flying comparable distances.
The analysis found that emissions intensity ranged from around 30g of CO₂ per passenger kilometre on the most efficient services to more than 800g on the least efficient ones. These disparities, the authors argue, point to a large and largely untapped opportunity to reduce aviation’s climate impact through better operational choices.
The authors found that airlines use a wide range of aircraft types, seating layouts and load factors, all of which influence how much fuel is burned per passenger. The paper suggests that if airlines were to deploy more efficient aircraft more consistently, increase passenger load factors and rely more heavily on higher-density seating configurations where appropriate, the sector could cut its total CO₂ output by almost 11% using only technologies and aircraft that are already in service today
The researchers also explored more ambitious scenarios, assuming that every flight operated with the most efficient aircraft available, filled most of its seats and adopted high-density layouts similar to those used by some low-cost carriers.
Under those conditions, the study estimates that global aviation emissions could be reduced by around half compared with current levels. While the authors stress that such a scenario is theoretical and would be difficult to achieve in practice, it serves to illustrate the scale of inefficiency that exists in the present system.
The findings add to an ongoing debate over how the aviation industry should pursue decarbonisation. Governments and airlines have largely focused on longer-term technological solutions such as sustainable aviation fuels, hydrogen-powered aircraft and carbon offsetting schemes. The Nature study does not dismiss those approaches, but it argues that relying on future technologies alone is risky, particularly given the rapid growth in air travel demand. Historically, increases in passenger numbers have tended to outpace gains in fuel efficiency, meaning total emissions continue to rise even as aircraft become more advanced.
By contrast, the study highlights that changes in how flights are scheduled, equipped and filled could deliver measurable emissions savings in the near term. Because these changes do not require new aircraft designs or fuel supply chains, they could, in theory, be implemented relatively quickly if supported by policy incentives or market pressures.
The authors suggest that efficiency-based fees, performance benchmarking or transparency requirements could encourage airlines to shift away from particularly inefficient aircraft and routes. And while aviation remains a difficult sector to decarbonise, the study indicates that meaningful emissions reductions are possible within the current system, provided efficiency becomes a stronger priority in how air transport is organised and regulated.