Advancing Aeronautics and Aerosol research to Accelerate Climate neutral aviation (A4Climate)

The mitigation of aviation non-CO2 effects, in particular contrails, could cut the radiative forcing from aviation by half in the next decade. Furthermore, the European Commission requires the Monitoring, Reporting and Verification of non-CO2 forcing agents by 2027. However, large uncertainties currently prevent the implementation of dedicated mitigation measures. A4Climate directly targets the complex challenge of reducing aviation non-CO2 effects by advancing knowledge on engine particle emissions, contrails and their climate impact. Specifically, A4Climate improves weather and contrail predictions and integrates new information on contrail predictability, accuracy, climate impact and cost in a real time software. The contrail prediction tool will be validated on 400 contrail avoidance flights, thereby leveraging the consortium’s expertise in the air transport system, weather and climate research. A4Climate creates further knowledge on contrail formation in the “low-soot regime” through dedicated lab measurements and models, filling gaps towards the assessment of the climate impact of modern lean burn and future hydrogenbased propulsion systems. Ultimately, A4Climate provides unique new atmospheric data on humidity, aerosols and contrails from an exceptional campaign with a research aircraft to improve process and climate models and to investigate fuel sulfur effects on contrails and low clouds.