Google Utilising AI to Mitigate Climate Impact of Contrails

Ubiquitous US tech giant Google is working with the airline industry to reduce the warming effects of contrails.

To test if pilots can choose routes that avoid creating contrails, Google Research teamed up with American Airlines and Breakthrough Energy to bring together huge amounts of data such as satellite imagery, weather, and flight path data and used AI to develop contrail forecast maps.

Contrails have been found to have a surprisingly large impact on the climate. A 2022 IPCC report noted that clouds created by contrails account for roughly 35% of aviation’s global warming impact, over half the impact of the world’s jet fuel.

The white trails 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 occurrence 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 Airlines 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 Research analysed satellite imagery and found that the pilots were able to reduce contrails by 54%. This is the first proof point that commercial flights can verifiably avoid contrails and thereby reduce their climate impact.

The other significant finding of Google’s test with American Airlines is the flights that attempted to avoid creating contrails burned 2% additional fuel.

Recent studies show that a small percentage of flights need to be adjusted to avoid the majority of contrail warming. Therefore, the total fuel impact could be as low as 0.3% across an airline’s flights.

This suggests that contrails could be avoided at scale for around US$5-25/ton CO2e (carbon dioxide equivalent) using existing predictions, making it a cost-effective warming-reduction measure and further improvements are expected.

Google Research says in conclusion on its work to date that contrail avoidance has the potential to be a cost-effective, scalable solution to reduce the climate impact of flying.