Cleaner Flight

Jet engine lubrication oil is an efficient nucleation agent that likely contributes to high levels of ultrafine particles near airports contributing to poor air quality, suggest laboratory thermodenuder experiments and observations near Frankfurt International Airport.

Burning sustainable aviation fuel blends with low levels of soot-producing aromatic components can result in a 50 to 70% reduction in soot and ice number concentrations and an increase in ice crystal size, suggest measurements of exhaust and contrail characteristics in two aircraft campaigns.

Only a small part of aircraft-soot–cirrus interactions succeeds in forming cloud ice, according to simulations with a numerical cirrus cloud model. This suggests that radiative forcing from aircraft soot may have been overestimated.

Europe’s aviation must reduce more than just flight CO₂ emissions to achieve net-zero. Synthetic fuels and carbon capture and storage could help but decreasing air traffic is crucial due to non-CO₂ climate impacts and resource constraints.

Decarbonizing the aviation sector is difficult given travel patterns and technical and economic constraints. Through nine holistic scenarios towards net-zero emissions from aviation by 2050, this study can inform investments and priorities for innovation to achieve a more sustainable aviation sector.

This study presents a global well-to-wake assessment of jet fuel greenhouse gas emissions with a range of 81.1-94.8 gCO₂e MJ⁻¹. Understanding this variability can improve decision-making amid the transition to decarbonizing aviation.

Demand for aviation will increase by 2–3-fold by 2050. Nonetheless, 90% decarbonization compared with 2019 can be achieved by continued efficiency gains in aircraft and operations, and by the use of ultra-green fuels derived from biomass or clean electricity. Achieving this decarbonization goal will require an increase in airfares of up to approximately 15%.

Efficiency and clean fuels won’t be enough. Governments and industry must experiment with other approaches to bring the climate impact of aviation close to zero.

Non-CO₂ effects must be addressed for climate-neutral aviation but are currently ignored in international climate policies. The authors provide a framework with different definitions of climate neutrality, then show how technological and demand-side mitigation efforts can help to achieve these targets.

The economic, technical, environmental and safety requirements of battery-powered aircraft are considered, and promising technologies and future prospects for battery innovation are discussed.