airplane contrails

Airlines Unite with Tech Sector and Academia to Tackle Climate Challenge of Aviation Contrails

The Contrail Impact Task Force is the first cross-sector forum to address the potential climate impact of contrails, the cirrus clouds that trail some aircraft.  

November 21, 2022 — Boulder, CO

Five major airlines today announced that they have joined forces with academic, technology, and nonprofit partners to launch the Contrail Impact Task Force. The cross-sectoral task force was established to explore the formation and mitigation of persistent condensation trails, or “contrails,” that affect the climate impact of flight. The task force was created by Alaska Airlines, American Airlines, Southwest Airlines®, United Airlines, Virgin Atlantic, Airbus, Boeing, Breakthrough Energy, Flightkeys, Google Research, Imperial College London, and nonprofit RMI.

Contrails form when high-heat exhaust from aircraft meets cold, humid air in the lower atmosphere during flight. Depending on atmospheric conditions, these formations can last for hours and evolve into persistent contrail-cirrus clouds. There is an emerging scientific consensus that some of these thin lines of cloud contribute to the total climate impact of flight by trapping heat that would otherwise be released into the atmosphere. The precise magnitude of impact remains uncertain, but sector leaders are nonetheless taking the first steps to define the challenge and explore solutions.

“The opportunity to address the climate impact of aviation contrails is immense. RMI is thrilled to help convene this group of leaders in the world of aviation to advance our understanding of contrail impacts and explore real-world solutions,” said Andrew Chen, Principal of Aviation Decarbonization in RMI’s Climate-Aligned Industries Program.

“We recognize that addressing the potential impact of contrails is an important step in our industry’s efforts on environmental sustainability,” said Helen Giles, Director of Environmental Sustainability at Southwest Airlines. “We were excited to host the task force’s first workshop at our headquarters in Dallas last month and look forward to learning more about contrail-cirrus and how each airline’s potential impact might vary based on its routes and schedule. Through this cross-functional collaboration, we hope to play a part in advancing the science in this area.”

“American Airlines is committed to finding innovative ways to advance the technologies aviation needs to reduce its environmental impact,” said Jill Blickstein, Vice President, Sustainability at American Airlines. “The Contrail Impact Task Force brings together an exceptional set of partners with the collective resources and expertise to develop effective contrail avoidance strategies long into the future.”

“The Contrail Impact Task Force will enable vital cross-sector collaboration, allowing us to better understand the science of contrails and, ultimately, to take action to address the issue,” said Lauren Riley, Chief Sustainability Officer for United Airlines. “United is committed to working with its task force partners to get the data necessary to develop strategies and best practices that support our ongoing sustainability efforts.”

“As we continue our work to reduce the climate impact of aviation, we know that collaboration is key to progress. The Contrail Impact Task Force is a great example — focused on sharing knowledge and enabling deeper understanding of the specific impact of contrails, with the goal to more effectively communicate the science and mechanisms behind that impact and to develop mitigating practices,” said Diana Rakow, Senior Vice President, Public Affairs and Sustainability at Alaska Airlines. “This work supports climate goals across our industry and our efforts at Alaska Airlines to reach net-zero carbon emissions by 2040.”

Not all flights result in contrails, and not all contrails have a warming effect. In fact, a small portion of flights may be responsible for the majority of warming contrails, according to recent studies. The task force plans to explore the use of contrail forecasting in flight planning to avoid these contrails, similar to how forecasting is already used to avoid air turbulence in flight.

“Contrail avoidance is a rare opportunity to address a potentially considerable part of climate change at what we expect to be very low cost,” said Marc Shapiro with Breakthrough Energy. “We have tools today to avoid regions with a high likelihood of contrail warming, and these tools can be implemented within existing flight and air traffic planning systems. Contrail-prone regions are just weather, and the aviation industry has a lot of experience working around weather.”

“Google believes that contrail avoidance has the potential to be a tremendously cost-effective form of climate mitigation,” said Juliet Rothenberg, Group Product Manager for Climate at Google Research. “We’re grateful to RMI for pulling together this cross-sector working group, as we are confident that the best way to mitigate climate change is for industry, academia, and tech companies to come together. We look forward to helping advise this task force on technological opportunities and look forward to seeing what we can achieve together.”

“Taking a step toward sustainable aviation can be, and should be, done today. Early simulations indicate that rerouting around contrail-sensitive areas could easily be accomplished by current flight optimization algorithms,” assured Raimund Zopp, Director of Innovation at Flightkeys. “In Flightkeys, we are already implementing our first contrail avoidance model in our system, and we are excited to test it with our customers and get the first results.”

“Our common goal is to enable the societal benefits of air transportation while reaching zero climate impact on our planet,” said Sheila Remes, Boeing’s Vice President of Environmental Sustainability. “We are excited to partner with the members of this task force to improve our collective understanding of persistent contrails and their total climate effects, and to advance solutions for our customers and the industry.”

“The understanding of aviation’s non-CO2 emissions impacts on climate has improved considerably over the past decade. Nonetheless, further research and real-time flight trials are indispensable to ensure future contrail mitigation solutions will be truly effective. We are therefore extremely motivated at Airbus to be part of this large-scale cross-industry project and to contribute to the joint efforts on advancing science, maturing prediction capabilities, and evaluating potential mitigation solutions based on an agreed metric”, stated Alain De Zotti, Senior Vice President of Engineering, Aircraft Architecture and Integration at Airbus.

The Contrail Impact Task Force has the goals of sharing and expanding on the latest science on the climate impact of contrails, developing actionable strategies to avoid warming contrails, analyzing the operational and financial challenges of implementing potential solutions, and establishing a roadmap for implementation and validation of contrail mitigation tools.

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Alexandra Jardine Wall, Strategic Communications Manager for the Climate-Aligned Industries Program, RMI:

About RMI

RMI, founded as Rocky Mountain Institute, is an independent nonprofit founded in 1982 that transforms global energy systems through market-driven solutions to align with a 1.5°C future and secure a clean, prosperous, zero-carbon future for all. We work in the world’s most critical geographies and engage businesses, policymakers, communities, and NGOs to identify and scale energy system interventions that will cut greenhouse gas emissions at least 50 percent by 2030. RMI has offices in Basalt and Boulder, Colorado; New York City; Oakland, California; Washington, D.C.; and Beijing. More information on RMI can be found at or follow us on Twitter @RockyMtnInst.