Google and the U.K. are using AI to reroute flights and reduce climate-warming contrails

Free daily briefing on global business news.

The 30-month Operation Blue Skies program will test altitude adjustments of up to 2,000 feet over the North Atlantic to prevent heat-trapping clouds from forming

David Paul Morris/Bloomberg via Getty Images

Google $GOOGL and the U.K. government launched a trial on Tuesday using artificial intelligence to predict where warming contrails will form over the North Atlantic and redirect flights to avoid those zones.

The 30-month program, called Operation Blue Skies, is the first state-backed effort to manage contrail avoidance across an entire oceanic airspace, according to Google. The program centers on Shanwick Oceanic airspace, which spans the eastern half of the North Atlantic corridor and is responsible for roughly 5% of global contrail warming.

At cruising altitude, the hot gases expelled by jet engines can trigger ice crystal formation when they encounter cold, humid atmospheric conditions; those crystals sometimes linger and expand into cloud layers that retain heat. Google estimates contrail warming is responsible for around one third of aviation's total climate impact.

The trial consortium includes Google U.K., air traffic control provider NATS, the Met Office, nonprofit research group Contrails.org, Imperial College London, and the University of Cambridge. Using satellite images and flight data, Google will pinpoint where aircraft have generated contrails in the past, then layer those findings against weather patterns to predict where new contrails are likely to form. NATS will then receive those forecasts so its controllers can steer pilots clear of the identified zones.

Controllers will primarily request vertical adjustments of roughly 2,000 feet rather than rerouting planes laterally — a maneuver pilots already perform regularly to sidestep turbulence, according to the BBC. Test flights will be conducted on select evenings and nights across the 2026-27 and 2027-28 winter seasons, periods chosen because air traffic is lighter, with roughly 20 to 40 nights of testing each winter.

During the designated test windows, the trial corridor is expected to see approximately 10,000 flights in total. Roughly 1% to 5% of those flights would be asked to deviate, which Paul Hodgson, Google's technical lead for the operation, said would be enough to demonstrate a statistically significant reduction in contrail formation across the airspace, according to the BBC.

An obvious concern with changing altitude is the potential for additional fuel burn. Earlier trial data indicated to Hodgson that any increase in fuel consumption would be far outweighed by the climate gains from contrail prevention. According to the BBC, the program's models put the fuel cost of a complete rerouting through Shanwick at approximately 100 kilograms per aircraft diverted.

The total program cost is £5 million, or about $6.76 million. Of the total budget, the Department for Transport is putting in £2.65 million; Google U.K., which is involved on a pro-bono basis, is adding £1.4 million in the form of AI research, engineering time, and computing resources, the company said. The results are expected to be published in academic literature.

Join 500,000+ readers who start their day with Quartz.

By subscribing, you agree to our Terms of Service and Privacy Policy.

Global business news for a smarter world