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The truth about contrails, and how AI could make them disappear
The thin white clouds that have drawn outlandish conspiracy theories could soon be a thing of the past
Look up, or out of the window for a moment. If it’s a clear day, and you are under a flight path, you may well see a thin white line, or perhaps many of them crisscrossing the sky. Some disappear within seconds, while some can tattoo the sky for hours.
Soon these condensation trails, shortened to “contrails”, could evaporate from our skies entirely. Airlines are under increasing pressure to reduce them because they have a damaging effect – though not in the way some conspiracy theorists would have you believe – and Google thinks it may have found a solution, with the help of artificial intelligence.
What are contrails?
If you have always thought of contrails as clouds created by planes, you aren’t a million miles off. Plane engines produce water vapour as a bi-product of burning kerosene. Because the air surrounding the aircraft is so cold, the water vapour combines with soot particles and turns to ice crystals. In humid conditions, fluffy, cloud-like contrails are then formed in the wake of the plane.
The concern is that these contrails are contributing to global warming. In certain weather conditions they can spread or merge, creating cirrus-like clouds which cover thousands of square miles and trap heat that would otherwise have left the Earth’s atmosphere. They do have the capacity to reflect sunlight back into space during the day, but the net effect is a warming one. A 2022 Intergovernmental Panel on Climate Change (IPCC) report said that contrails account for 35 per cent of aviation’s global warming impact.
The AI solution
However, a research team from Google, American Airlines and Breakthrough Energy (a sustainable tech firm started by Bill Gates) think they might have cracked the problem. American Airlines pilots flew 70 test flights over six months, using AI-based predictions made by Google and cross-referenced with Breakthrough Energy’s open-source contrail models, to avoid flying at altitudes likely to create contrails.
It seems to have worked. Satellite imagery suggests the pilots cut contrails by 54 per cent. The IPCC published a report just last year suggesting that contrail avoidance could take “up to a decade to mature”, but these findings suggest the technology could be ready much sooner than expected.
“This is the first proof point that commercial flights can verifiably avoid contrails and thereby reduce their climate impact,” write Carl Elkin and Dinesh Sanekommu in a Google Research blog post.
The catch
There is a catch, which is that these test flights needed to burn 2 per cent more fuel in order to find suitable routes to avoid creating contrails. However, Google says that the total increase in fuel usage across all of an airline’s flights would be just 0.3 per cent, because most contrails are formed only by a small number of flights at specific altitudes.
Aviation expert John Strickland tells the Telegraph that there are layers to the contrails debate. “It’s undoubtedly a positive development but needs to be viewed in a broader context of airline operations,” he said.
“As is acknowledged, some flights may burn more fuel as a consequence of contrail avoidance and other factors could affect the on-the-day ability to do so. For example, weather conditions may prohibit or require certain routings. As can air traffic management requirements, air space congestion, total journey time and security considerations.”
What about those conspiracy theories?
Some conspiracy theorists will tell you that the discussion about the warming effect of contrails is avoiding the real issue at hand. The “chemtrails” theory claims that shady global organisations are involved in a secret plot to pump toxic chemicals into the atmosphere. Alleged motivations range from the reduction of life expectancy to weather control. The chemtrails theory is widely debunked by scientists.
“We have not seen any credible evidence that chemtrails exist,” says David Keith’s Research Group of Harvard University. “If we did see any evidence that governments were endangering their own citizens in the manner alleged in the chemtrails conspiracy, we would be eager to expose and stop any such activities.”
The research group says that – aside from the absence of any evidence – such a program of dumping toxic material, on the scale that is suggested, would involve a huge operation involving many thousands of individuals. Considering the project itself would be to bring harm to people (including the workers involved, and their families), it is hard to imagine this being kept a secret.
The project to remove contrails from the atmosphere is just one of the ways that the aviation industry is trying to reduce its carbon footprint, with many major airlines signing a pledge to hit net zero by 2050. The development of green airships, the dawning of suborbital long-haul flights and the second coming of more fuel-efficient supersonic flights are three ways in which aviation as we know it could be revolutionised in the coming decade.
How else is AI changing the way we travel?
Facial recognition at airports
Airports are increasingly investing in facial recognition software to match a passenger’s face with their passport. In some airports in the US, travellers are able to sidestep presenting any identification at all, as the program matches their face to a database of government-approved photographs.
Gatwick is one UK airport that has the capacity for facial recognition. They say: “Facial recognition is perfectly safe and works with adults and children and does not always require glasses and hats to be removed. We use this system to provide irrefutable evidence that passengers boarding a domestic or Common Travel Area (CTA) flight are the same individuals who entered the airport’s international departure lounge.”
Chatbots replacing human customer service
Many airlines use an automated chatbot to handle customer queries, which will go to great lengths to answer your question before directing you to a skin-and-bones human on the end of a phone. Some are concerned that chatbots remove a crucial element of human interaction, particularly in an industry built on face-to-face customer service like travel.
Planning your next holiday
ChatGPT is able to answer questions and solve problems, including where you should go on your next holiday. Our chief culture and consumer editor, Nick Trend, says we are not too far off AI being able to build sophisticated trip plans: “It is already pretty much at the point where it can generate a detailed travel itinerary in a few seconds. I asked for a suggestion for a one-week tour of Andalucia and was given reasonable suggestions for a different destination each day, plus sights and activities.”