How AI Could Help Planes Avoid Warming Contrails
Google and the UK government are launching a £5 million trial using artificial intelligence and advanced weather forecasting to help aircraft avoid the atmospheric conditions that create persistent warming contrails over the North Atlantic, potentially reducing part of aviation’s climate impact without changing the aircraft themselves.
What Are Contrails And Why Do They Matter?
Contrails are the white lines that sometimes form behind aircraft when water vapour from jet exhaust freezes into tiny ice crystals in very cold air. Many disappear quickly, but under the right temperature and humidity conditions they can persist for hours, spread into larger cloud formations and trap heat that would otherwise escape from the Earth’s surface.
Google estimates that warming contrails account for roughly one third of aviation’s total climate impact. That makes them an attractive target to tackle because, unlike replacing aircraft fleets or developing new propulsion technologies, avoiding the worst contrails may require only relatively small changes to how existing flights are operated.
The Met Office says that two aircraft flying at slightly different heights can experience very different conditions, with one producing a persistent contrail while the other does not. Accurate forecasts could therefore identify troublesome layers of air before an aircraft reaches them.
How Will Operation Blue Skies Work?
The project between the UK government and Google, dubbed “Operation Blue Skies”, will operate in Shanwick airspace over the eastern North Atlantic, an area that accounts for around 5 per cent of global contrail warming. It is described as the world’s first state-backed trial to test contrail avoidance across an entire oceanic airspace rather than with individual airlines.
Google UK says it will develop AI models using satellite imagery, flight information and weather data to predict where strongly warming contrails are likely to form. The Met Office says it is developing a new contrail-impact forecasting capability, while NATS (the UK’s leading air traffic control provider) will use the forecasts during normal air traffic operations so selected aircraft can be asked to make relatively small altitude changes.
Google says: “Our AI-powered forecasts have enabled flight crews and air traffic controllers to make targeted adjustments that avoid contrail-sensitive regions while remaining within normal flight operations.”
A 30-Month Programme
The 30-month programme includes operational trials during the winters of 2026/27 and 2027/28. Around 10,000 flights are expected to pass through Shanwick during trial hours each year, although only a small proportion will be diverted so researchers can compare outcomes.
Why Use Weather Intelligence?
Contrail formation depends heavily on local atmospheric conditions, particularly temperature and humidity at cruising altitude. If those conditions can be forecast accurately enough, controllers may be able to move aircraft above or below the layers where persistent contrails are likely to develop.
Emma Corrigan, an aviation expert at the Met Office, said: “Every day, our forecasts help airlines, airports, air traffic controllers and pilots make informed decisions. Through this programme, we are exploring how those same weather and climate science capabilities could help address environmental challenges for aviation.”
The combination of AI and increasingly detailed atmospheric forecasting is therefore intended to identify precisely where intervention is worthwhile, rather than asking aircraft to make unnecessary changes throughout their journeys.
What About The Extra Fuel?
Avoiding contrails is not automatically beneficial because changing altitude can cause an aircraft to burn more fuel, increasing carbon dioxide emissions. The important question is whether the warming avoided by preventing a persistent contrail is significantly greater than the climate cost of the extra fuel used.
That trade-off is one reason independent scientific verification is built into the programme. Imperial College London and the University of Cambridge will assess the trial results, while the Met Office will help evaluate forecast performance and scientific uncertainties.
James Shapland, Head of Regulated Transport Services at the Met Office, said: “Our understanding of regional weather regimes will provide an important scientific basis for the trials, and developing a global contrail forecast capability aligns with our strategic work to support the aviation industry in managing its longer-term environmental impacts.”
A Complement, Not A Cure
Contrail avoidance will not remove aviation’s carbon emissions and is not being presented as a substitute for sustainable aviation fuel, more efficient aircraft or cleaner propulsion technologies. Its attraction is that it could provide a relatively quick operational improvement while those longer-term technologies continue to develop.
Google describes contrails as “one of the most urgent yet solvable climate challenges facing aviation today” and says the trial aims to provide a validated blueprint for reducing aviation’s climate impact through airspace management.
The £5 million programme is supported through the UK government’s Aerospace Technology Institute Programme, while Google is contributing £1.4 million in research expertise, engineering time and high-performance computing on a pro bono basis. Government grant funding goes directly to the academic, non-profit and aviation partners involved in the project.
What Does This Mean For Your Business?
The wider business lesson here is that sustainability improvements do not always require replacing existing infrastructure. For example, Operation Blue Skies is attempting to reduce environmental impact by combining better data, AI and operational decision-making around aircraft that would be flying anyway.
That principle can apply far beyond aviation, with businesses potentially finding some of the quickest gains by identifying where relatively small changes to scheduling, routing, energy use or operating procedures can prevent disproportionately large amounts of waste or emissions.
Operation Blue Skies also highlights the importance of measurement, because the project is designed not only to identify where an intervention could have the greatest effect, but also to independently assess whether the environmental benefit genuinely outweighs any additional fuel used. Businesses taking a similar approach to sustainability should therefore focus on changes whose overall impact can be measured, rather than adopting initiatives that appear greener in isolation but may deliver little real benefit.
If Operation Blue Skies succeeds, it could demonstrate that one of aviation’s significant climate effects can be reduced not by redesigning the aircraft, but by helping them fly through slightly different parts of the sky.
