Contrail avoidance: the magic bullet to rapidly cut aviation’s climate footprint
Anna Krajinska, UK Director
| Transport & Environment
Contrails warm the planet almost as much as all aviation CO₂ emissions. Anna Krajinska explains why contrail avoidance is a low-cost, high-reward climate solution the UK cannot afford to ignore.
Look up on a clear day and you will often see streaks of white stitched across the blue sky. These are contrails – condensation trails created when aircraft pass through cold, humid layers of atmosphere. While many vanish within minutes, others linger, turning into human-made clouds that trap heat. Experts warn these persistent contrails warm the planet about as much as all the CO₂ emissions from aviation itself.
The solution? Contrail avoidance. It’s one of the simplest, cheapest, and most effective tools available to slash aviation’s climate footprint – and it can be done quicker than other aviation climate fixes.
The research is compelling. Less than three per cent of all flights worldwide are responsible for 80 per cent of the climate-warming effect caused by contrails.1 By making minor adjustments to the flight altitudes or routes of these most problematic flights, global contrail warming could be cut by more than 50 per cent by 2040.2
And the cost? Negligible. The added expense for airlines would be minimal – the added price on a London to New York ticket would be under £4 – less than one per cent of the fare. Yes, airlines need to burn a bit more fuel, but real-world airline trials have demonstrated that the climate benefit from contrail avoidance is at least 15 times greater than the CO₂ penalty from marginally higher fuel consumption,3 and potentially as much as 40 times greater, with benefits realised immediately rather than over decades.4
The Intergovernmental Panel on Climate Change (IPCC) acknowledged the climate impact of contrails more than twenty-five years ago, yet meaningful action has still not been taken.5 Experts describe contrail avoidance as a “no-regrets” climate solution – one that delivers immediate benefits with minimal disruption to passengers or air traffic.
Currently, the UK is lagging behind Europe on contrail policy. The EU has already taken decisive steps, requiring airlines to monitor and report contrail forming non-CO₂ emissions under its Emissions Trading Scheme (ETS). Expanding the UK’s own ETS to include these emissions would create the same accountability, incentivising airlines to adjust high-risk flights and ensuring aviation’s full climate impact is addressed as part of UK’s net-zero commitments. The UK’s airspace management rules should also be reviewed to incorporate contrail avoidance.
This is the climate opportunity of the decade. With airport expansion on the horizon, failing to act risks a surge in contrail pollution that could wipe out progress toward net-zero.
The choice is clear: swift contrail policy could make the skies part of the solution, not the problem. The Labour government must seize the lead up to COP30 as its moment to act – before aviation’s white streaks turn into a dark cloud over its climate promises.
- Teoh et al (2024), Global aviation contrail climate effects from 2019 to 2021, Atmospheric Chemistry and Physics, 24, Volume 24, Issue 10
- Transport & Environment (2024), Contrail avoidance: aviation’s climate opportunity of the decade
- Sonabend et al. (2024), Feasibility test of per-flight contrail avoidance in commercial aviation. Communications Engineering 3, 184
- Transport & Environment (2024), Contrail avoidance: aviation’s climate opportunity of the decade
- IPCC (1999), Aviation and the Global Atmosphere
