Contrails: A policymaker's guide
Reducing contrails – those silver streaks that form across cold, humid skies - is the closest thing we
have to a silver bullet to dramatically reduce the climate impact of aviation.
The warming effect of contrails means they will make up 35% of aviations climate impact over the next 100 years. But because they are intense and short lived, reducing them now could reduce flight emissions by 50% by 2040.
And the good news is that this would need adjustments to less than 2% of flights, there are technological solutions available, and key players in the aviation industry such as academics, flight-path providers as well as some airlines are already working together to predict, trial and monitor contrail avoidance.
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Top 5 things to know about contrails
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How can we reduce contrails?​
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We can easily decrease contrail formation by around 60%. As contrails are responsible for 35-50% of a flight's climate warming effect, this means a 20-30% reduction of aviation’s climate impact.
The policy landscape is forming around aviation’s CO2 emissions, including emissions trading and fuel standards. However, the main focus is on ‘Sustainable Aviation Fuel’ (SAF). This is highly unlikely to meet the industry’s supply requirements by 2050, and the large land requirement for producing many SAFs casts serious doubt on their sustainability credentials, especially with increasingly extreme weather events and the resulting pressure on land.
Conversely, policies for aviation’s non-CO2 emissions aren’t ambitious enough. The EU has implemented a monitoring, reporting and verification framework (MRV) for non-CO2 emissions from 1 January 2025 but only for flights within the European Economic Area (EEA) and from the EEA to the UK and Switzerland. Long-haul flights won’t be required to monitor until 1 January 2027.
But emission reductions are possible now. Effective policies are the final part of the solution.
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