UK Tests AI to Help Planes Reduce ‘Sky Graffiti’

A £5 million UK trial will test whether artificial intelligence (AI) can help aircraft avoid areas where their vapour trails are likely to contribute to global warming.

The 30-month Operation Blue Skies project will use AI, satellite images, flight data and weather information to predict where warming contrails are likely to form. Aircraft could then be directed around those areas, mainly by changing their altitude.

The trial will focus on the Shanwick Oceanic airspace in the eastern half of the North Atlantic corridor, an area estimated to account for about 5% of global contrail warming.

The project brings together Google, the UK government, the Met Office, air traffic control provider National Air Traffic Services (NATS), the University of Cambridge and Imperial College London.

Contrails, also known as vapour trails, are formed when hot exhaust from aircraft engines meets very cold air at high altitude. This creates ice crystals that can form visible white lines behind aircraft.

Many contrails disappear within a short time. However, when the atmosphere is particularly cold and humid, they can remain for longer and spread into cloud-like formations.

These clouds can trap heat that would otherwise escape from the Earth, contributing to climate change.

Dr Paul Hodgson, Google’s technical lead for Operation Blue Skies, told the BBC’s Tech Life programme that contrails could have a significant impact on aviation’s contribution to climate change.

He said his five-year-old child has a more colourful description for the white trails, calling them “sky graffiti”.

“We think that contrail warming is responsible for something like a third of all aviation climate warming,” he said.

Dr Hodgson acknowledged that there is still uncertainty about the exact contribution of contrails to global warming. However, he said scientists were confident that it was “either quite a large problem or a very large problem”.

How the AI system will work

Under the project, Google will use satellite images and flight data to identify locations where aircraft have previously produced contrails.

The information will then be combined with weather patterns to predict where atmospheric conditions are likely to create new contrails.

The forecasts will be passed to NATS, where air traffic controllers can advise pilots to avoid areas with a high risk of producing warming contrails.

The trial is not expected to require major changes to flight routes. Instead, most adjustments will involve changing the altitude of aircraft by about 2,000 feet.

Such changes are already common in aviation, as pilots regularly adjust altitude to avoid turbulence and bad weather. As a result, passengers are unlikely to notice significant differences.

Ian Jopson, director of sustainability at NATS, said the system would fit into existing procedures.

He described it as “pretty much business as usual using existing procedures for the operators on the North Atlantic”.

Testing will take place during selected evenings and nights in the winters of 2026-27 and 2027-28, when there is less air traffic.

About 10,000 flights are expected to pass through the selected airspace during the trial periods. However, only a small number are expected to require altitude changes specifically to avoid contrails.

The UK’s Department for Transport is providing £2.65 million towards the project, while Google is contributing £1.4 million through AI research, engineering and computing infrastructure.

Questions over climate benefits

The project comes as the UK government supports the expansion of airports, raising questions about whether technology can reduce aviation’s environmental impact as demand for air travel increases.

There are also concerns about the environmental impact of the growing use of AI itself, as major technology companies invest billions of pounds in large data centres that require significant amounts of electricity.

A key question for Operation Blue Skies is whether changing aircraft altitude to avoid contrails will create additional carbon emissions by requiring planes to burn more fuel.

Aviation Minister Keir Mather said the project would examine whether “small tweaks to flight paths over the Atlantic” could make flying cleaner.

“This is a world-first, and it’s British ingenuity leading the way,” he said.

Dr Hodgson said previous trials suggested that the extra fuel required would be much smaller than the climate benefit of preventing warming contrails.

“The CO2 penalty is in the order of less than 1%, compared to the contrail cost, which is of a similar order magnitude to all of the CO2 of aviation,” he said.

Modelling for Operation Blue Skies indicates that a full deviation through Shanwick airspace could require an affected aircraft to use about 100kg of additional fuel.

Previous trials involving airlines have achieved reductions of between 60% and 70% in contrail formation or warming, according to Dr Hodgson.

The results of Operation Blue Skies are expected to be published in academic journals and made available for wider scientific review.

Researchers hope the findings will provide clearer evidence on whether AI-guided changes to flight paths can reduce aviation’s impact on climate change without significantly disrupting air travel.

Source: BBC