Dr. Sebastian Eastham: How Atmospheric Modeling and Contrail Mitigation Are Shaping Sustainable Aviation

Contrails, seemingly harmless long, white streaks that trail aircraft, are significant contributors to the environmental impact of aviation. Current research estimates that contrails account for 20-50% of aviation’s total contribution to climate change, and therefore addressing the formation of these contrails is an urgent priority in the journey towards a more sustainable aerospace industry.

EcoAero had the opportunity to talk to Dr. Sebastian D. Eastham from Imperial College London, who is also affiliated with the MIT Laboratory for Aviation and the Environment. Dr. Eastham specializes in atmospheric modeling and the environmental impact of aviation, with a focus on understanding the chemical and physical processes that contribute to climate change. His insights provided a deeper understanding of the current efforts and challenges in mitigating the effects of contrails.

Contrails are essentially artificial cirrus clouds formed when aircraft pass through cold and humid atmospheric layers. These ice clouds trap heat in the Earth’s atmosphere, enhancing the warming effect. To mitigate this, Dr. Eastham and other researchers have proposed strategies like contrail avoidance, which involves identifying atmospheric zones conducive to contrail formation and altering flight paths to bypass them entirely. Advances in satellite technology have become crucial in this effort. Researchers, including Dr. Eastham, have leveraged geostationary satellites to detect contrails within 30 minutes to three hours of their formation. By determining the altitudes and regions most susceptible to contrails, flight paths can be adjusted in near real-time to avoid contributing to these warming phenomena.

Understanding and mitigating contrails also relies heavily on computational modeling. Dr. Eastham notes that the use of intermediate fidelity models, such as the APCEMM, bridges the gap between low-resolution global climate models and highly detailed simulations. While high-fidelity models provide the most accurate predictions, they require immense computational power, making them impractical for large-scale analysis. In contrast, intermediate models offer quicker insights that help simulate scenarios such as the impact of reduced soot or sulfur emissions.

While academic research drives contrail mitigation strategies, the aerospace industry faces difficulties in adopting these strategies. Dr. Eastham explains that commercial enterprises prioritize profitability, and immediate economic benefits from contrail reduction are not always evident. However, external pressures, such as potential regulations and customer demand for sustainability, are encouraging companies to invest in this area. Programs like ARPA-E’s PRE-TRAILS initiative exemplify public-private collaboration. Industry giants such as GE Aerospace and Boeing are focusing on technological hurdles like improving humidity sensing, a key factor in predicting contrail-prone areas. Additionally, flight trials with airlines such as Delta and Lufthansa are generating valuable data to refine contrail avoidance methods.

Emerging technologies in supersonic travel raise new sustainability concerns, such as increased emissions of nitrogen oxides and water vapor at high altitudes, which can exacerbate ozone depletion and climate impacts. Dr. Eastham believes that addressing these challenges early on is crucial to ensure that future advancements in aerospace technology do not come at the cost of environmental sustainability.

Contrail mitigation is an example of the complexities of balancing technological innovation, environmental sustainability, and industry feasibility. While contrails are a significant contributor to aviation's climate impact, advancements in satellite detection, computational modeling, and industry engagement offer hope for meaningful reductions. Ultimately, collaboration across academia, industry, and policy is essential to ensure that aviation continues to serve as a cornerstone of modern life—connecting people and ideas—without compromising the health of our planet. As Dr. Eastham emphasizes, the key to progress lies in coordinated efforts and a shared commitment to sustainability.

EcoAero is dedicated to continuing efforts to ensure that work is done to promote sustainability in aerospace as well as advancements to mitigate challenges like those Dr. Eastham is researching. By fostering collaboration and raising awareness, we aim to contribute to a more sustainable future for aviation and beyond.