Additional Coverage:
- The UK and Google are testing changes to flight paths to tackle aviation’s climate impact (apnews.com)
A new international effort aims to reduce the climate impact of aviation by adjusting flight altitudes over the northeastern Atlantic Ocean. Beginning this winter and continuing through the next, hundreds of commercial flights passing through a busy transatlantic corridor will be asked to slightly alter their routes to avoid forming contrails-those thin, white streaks in the sky that contribute to global warming.
The British government is backing this innovative 30-month trial, known as Operation Blue Skies, which uses artificial intelligence developed by Google UK to forecast where contrails are likely to form. When airplanes fly through cold, humid air, ice crystals can develop around engine emissions, creating contrails that trap heat and warm the planet. The Shanwick Oceanic Control Area, which handles significant air traffic between Europe and North America, is a prime location for such formations.
During designated test periods-around 20 to 40 days each winter-air traffic controllers will instruct some flights to adjust their altitude by up to 2,000 feet (610 meters) to avoid contrail-prone areas. These modest altitude shifts fall well within standard flight operations and will be coordinated through existing air traffic control channels. Out of roughly 10,000 flights traversing the Shanwick airspace during testing, about 1% to 5% will make these adjustments, a range sufficient to measure meaningful reductions in contrail formation, according to Paul Hodgson, Google’s technical lead on the project.
Individual airlines have previously experimented with altitude changes to limit contrails. Earlier this year, Google and American Airlines reported success using AI-driven forecasts to reduce the climate impact on select flights. Operation Blue Skies seeks to expand this approach across an entire flight corridor, potentially offering a scalable solution for airspace-wide contrail mitigation.
Contrails are responsible for an estimated 1% to 2% of global warming, according to Contrails.org, a nonprofit focused on reducing aviation’s climate footprint. Modeling indicates that the Shanwick airspace alone contributes about 5% of the warming effect attributed to contrails, with the highest impact during winter months.
Keir Mather, the UK aviation minister, emphasized the government’s commitment to supporting British innovation in cleaner flying technologies. The UK government is covering more than half of the £5 million ($6.76 million) study’s cost. Google describes contrails as one of the most urgent but addressable climate challenges facing the aviation industry today.
Hodgson noted that testing contrail avoidance on an airspace scale-rather than through isolated airline efforts-can demonstrate how multiple flights can be rerouted simultaneously to reduce overall contrail formation, potentially creating a model for other busy airspaces worldwide.
The consortium leading Operation Blue Skies includes Google, the UK Department for Transport, the Met Office, the UK’s primary air navigation service provider NATS, Contrails.org, Imperial College London, and the University of Cambridge. A 2020 study from Imperial College found that minor flight path adjustments could significantly lower contrail-related climate impacts. Professor Marc Stettler described this trial as an unprecedented opportunity to test these findings in real-world conditions on a large scale.