Understanding Contrail Management: Opportunities, Challenges, and Insights

Abstract

The following report examines the state of science and mitigation of contrails — the linear clouds created by aircraft in cold and humid air — including an overview of the current approaches and efforts to better understand and address their significant climate impact. Contrail management, including contrail avoidance by rerouting flights, presents an opportunity for stakeholders across the aviation sector to engage in radical collaboration to reduce non-CO2 climate impacts alongside ongoing aviation decarbonization efforts. This report was created in collaboration with participants of the RMI-convened Contrail Impact Task Force, which comprises stakeholders across the aviation sector, including industry organizations, airlines, academic institutions, non-governmental organizations, private companies, and government entities. It provides a comprehensive overview of the current understanding of the climate impact of contrails as well as research and implementation efforts that support the following key points: The climate impact of contrails is significant but solvable. Contrail-induced warming is a concentrated problem with targeted, promising solutions. While contrail formation is driven by complex and dynamic atmospheric conditions, forecasting models are being developed to predict persistent contrails. To ensure model accuracy, reliable input data is critical and validation efforts must be scaled up. The most significant source of continued uncertainty is a lack of accurate humidity data at cruising altitude. Ongoing flight trials are testing the operational implications of contrail avoidance and providing crucial insights for contrail prediction improvements. Continued collaboration on research and participation in large-scale flight trials can increase the collective understanding of the climate impact of contrails and support the improvement of prediction models. Measuring the climate impact of contrails is critical to evaluating the full climate impact of aviation.