Air travel accounts for less than three per cent of global energy-related carbon dioxide emissions. Yet its climate impact is disproportionately high and not just because of CO₂, but due to something far more elusive - contrails.
What Are Contrails and Why Do They Matter?
Contrails are those white streaks trailing behind aircraft. They are more than just sky graffiti. They form when water vapour from jet engines condenses around soot particles at high altitudes, creating ice crystals. Under certain conditions, especially in ice supersaturated regions (cold and humid air), these crystals persist and spread into cirrus clouds.
Unlike lower altitude clouds that reflect sunlight and cool the Earth, contrail cirrus clouds trap heat, amplifying aviation’s warming effect. This makes contrails a significant contributor to climate change, despite being a non-CO₂ emission.
Small Changes, Big Impact.
Less than three per cent of flights cause 80pc of contrail-related warming, mostly over Europe, North America, and the North Atlantic. That’s because these regions have dense air traffic at altitudes ideal for contrail formation.
The solution? Rerouting flights to avoid contrail-prone zones. While this may slightly increase fuel use and CO₂ emissions, the net climate benefit is substantial. In fact, rerouting just two per cent of flights could halve contrail warming.
Visualising the Invisible.
To help audiences understand this phenomenon, Financial Times senior visual journalist Steven Bernard created a dynamic animation using Adobe Illustrator, Photoshop, and After Effects. The animation, embedded using the Bodymovin plugin, showcases contrail formation and its climate impact in crisp SVG vector format.
“These self-contained components allow us to embed fully customised content and interactive graphics into online articles, enabling stories to be told in richer, more dynamic ways,” explains Emma Cipolla, FT’s associate product manager.
Who Should Pay?
There’s growing political momentum to shift the burden of aviation emissions from airlines to frequent flyers and private jet users. Funds raised could support rail, road, and port infrastructure, offering greener alternatives to short-haul flights.
This approach tackles a relatively small slice of global emissions, but symbolically it’s huge, highlighting the need for political and social will to address aviation’s environmental footprint.
A Greener Sky Is Possible.
Flying greener doesn’t mean flying less. It means flying smarter. By understanding and mitigating contrails, we can make meaningful strides toward climate-friendly aviation.
