A collaboration between American Airlines, Google Research and Breakthrough Energy is demonstrating that AI can be used to help avoid forming contrails, which account for roughly one third of aviation’s global warming impact.
Contrails - the thin, white lines you sometimes see behind airplanes - have a surprisingly large impact on our climate. The 2022 IPCC report noted that clouds created by contrails account for roughly 35 percent of aviation's global warming impact, over half the impact of the world’s jet fuel. Google's bog reports that they teamed up with American Airlines and Breakthrough Energy to bring together huge amounts of data - like satellite imagery, weather and flight path data - and used AI to develop contrail forecast maps to test if pilots can choose routes that avoid creating contrails.
Contrails form when airplanes fly through layers of humidity and they can persist as cirrus clouds for minutes or hours depending on the atmospheric conditions. While these extra clouds can reflect sunlight back into space during the day, they also trap large amounts of heat that would otherwise leave the Earth’s atmosphere. This creates a net warming effect. Avoiding flying through areas that create contrails can reduce warming. The challenge is knowing which flight routes will create contrails.
A group of pilots at American flew 70 test flights over six months while using Google’s AI-based predictions, cross-referenced with Breakthrough Energy’s open-source contrail models, to avoid altitudes that are likely to create contrails. After these test flights, Google analyzed satellite imagery and found that the pilots were able to reduce contrails by 54 percent.
This is the first proof that commercial flights can verifiably avoid contrails and thereby reduce their climate impact. It will certainly be good news if contrail avoidance has the potential to be a cost-effective, scalable solution to reduce the climate impact of flying.