Aircraft contrails

Aircraft contrail climate effects and mitigation

Contrails are line-shaped clouds made up of ice crystals that are formed from black carbon particles emitted by aircraft engines. They form and persist only in regions of the atmosphere that are cold and humid enough. Individual contrails trap outgoing longwave radiation and cause a warming effect, but can also reflect incoming solar radiation with a cooling component. On aggregate, however, the consensus is a net warming effect and its annual climate forcing could be equal or higher than the cumulative CO2 that is emitted by aviation since its inception. In this presentation, we will model the contrail climate forcing in the North Atlantic region over 5 years and identify the set of factors that are associated with highly warming/cooling contrails. New mitigation ideas are then devised based on these findings, including a targeted use of sustainable aviation fuels and prioritising mitigation for flights with the highest probability of forming strongly warming contrails.


Dr Roger Teoh is a Research Associate at Centre for Transport Studies in the Department of Civil and Environmental Engineering, Imperial College London. Roger’s current research interests is on aviation and climate change, with the aim to evaluate and mitigate the climate impact of aviation emissions and contrail cirrus. His work is largely quantitative based, which includes the modelling of flight trajectories, aircraft fuel consumption, exhaust emissions and the lifecycle of contrails. Roger completed his PhD in aviation and the environment at Imperial College London in 2020, funded by The Lloyd’s Register Foundation Scholarship and the Skempton Scholarship.

About Energy Futures Lab

Energy Futures Lab is one of seven Global Institutes at Imperial College London. The institute was established to address global energy challenges by identifying and leading new opportunities to serve industry, government and society at large through high quality research, evidence and advocacy for positive change. The institute aims to promote energy innovation and advance systemic solutions for a sustainable energy future by bringing together the science, engineering and policy expertise at Imperial and fostering collaboration with a wide variety of external partners.