About Contrail Awareness
Contrail Awareness is a UK-based, volunteer-run and self-funded campaign group with two missions:
1. Raising public awareness regarding the severe climate impact of Aviation's non-CO2 effects (contrails).
2. Helping to accelerate the implementation of contrail management in the UK and around the world through public pressure.
We help the public understand the science behind the climate impact of contrails as well as the solution: contrail avoidance.
We also provide the public with opportunities to call for more transparency and action on contrails from the Government and the aviation industry, through petitions, open letters and communication templates.
We hope for a future where both the non-CO2 and CO2 climate impacts of aviation are fully acknowledged and addressed, allowing for true sustainability in the aviation sector and the reduction of global warming.
Contrail Awareness was formed in May 2026 by Toby Gay, a master's student in Environmental Law, Politics and Governance at Birkbeck College, University of London.
Scroll down to see our values and positions
Values
Transparency
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We believe that overcoming any problem first requires the problem to be recognised and acknowledged.
Most people have never heard of contrails, and they are often confused with the 'chemtrails' conspiracy theory. In fact, they were 5 times ,more searches on Google last year for 'chemtrails' than 'contrails.
To address this, we think that governments and the airline industry need to be more actively transparent about the non-CO2 climate impact of aviation (contrails), thereby allowing the public to make informed decisions about their travel choices.
Equally, we are fully transparent about our motivations, finance and information sources, and organisational structure. We are open to comments, constructive criticism and thoughts on current and future campaigns. Please get in touch with us here.
Environmental and Social Justice
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We believe that Climate Change is a Human Rights and Social Justice issue. Aviation is a major example and driver of this. It represents 19% of our remaining temperature budget but 80% of people have never taken a flight. 1% of the world’s population is responsible for 50% of the world’s aviation emissions, which becomes 54% when private jets are taken into account. UK-attributable aviation is responsible for 8% of the country’s emissions, even though global aviation emissions only make up 2-3% of the world’s total. The people least likely to take a flight are also the most likely to be affected by climate change.
Contrails fit into this pattern: The worst warming contrails are formed over Europe and the North Atlantic, where 5% of total flight miles are flown but 10-11% of contrail warming originates from. The total global emissions equivalent of contrails is comparable to a country the size of Germany. In spite of this, the worst effects of Climate Change are felt by the most vulnerable and least responsible communities. Because of this, we believe that developed nations like the UK have a responsibility to lead on regulating contrails, ensuring the transition to a sustainable aviation sector, and preventing the worst effects of climate change.
Collaboration
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We recognise organisations like Contrails.org, Blue-Lines.org, Plane Sight News and many others, which have worked tirelessly to establish the science behind contrails and contrail avoidance, and monitor and report airline and government (in)action on aviation’s non-CO2 climate impact.
We also acknowledge the work of organisations like Stay Grounded, Bumprints, Transport & Environment, Opportunity Green, Possible, Flight Free UK, Safe-Landing.org and many others which are pushing for a significant reduction in the CO2 impact of the aviation industry.
We note the importance of working together with these organisations to help ensure a socially just and speedy transition to a sustainable aviation industry, with regards to both CO2 and non-CO2 effects. In the same way, we recognise the need for the separate actors in the aviation sector (including governments) to work together to improve transparency around contrails, increase trials for contrail avoidance, and ultimately resolve this issue.
Position statements
1. On the uncertainty and quantification of the warming effects of contrails, and the precautionary principle
We acknowledge the current uncertainty surrounding the climate impact of contrails, which is exacerbated by the fact their effects last for a much shorter time than CO2 (which can remain in the atmosphere for 1000s of years whereas contrails linger for only a few hours). However, as the opening line of the March 2026 report by the Contrail Impact Mitigation Task and Finish Group, commissioned by the UK Government, makes clear: "Aviation's contrail climate impact is significant". It goes on to say: "There is consensus that contrails cause a net positive radiative forcing (warming)."
The current scientific understanding is that contrails have warming effects equal to or greater than that of the CO2 emitted from airplanes over a 20-year period. Over a 100-year period, this decreases to about 25%. We focus on the former figure (50%), and the 20-year timeframe, to reflect the wider urgency that is desperately needed not only to address aviation’s growing climate impact, but also the climate crisis in general. This approach also highlights the target set by the Paris agreement of avoiding the +2°C limit by 2050 and the fact that, as T&E point out, “planes keep flying every day, so new contrails keep forming and continuously adding to the warming effect. The problem does not disappear; it is like trying to mop up a floor while leaving the tap running.”
Regardless of how severe the climate impact of contrails is or what metric is used to quantify it, we believe the public has a right to know about this issue. This forms the central tenet of our first mission to educate the public about contrails and possible solutions like contrail avoidance, so that people can make informed about their travel choices.
Our second mission is informed by the precautionary principle (enshrined into international law by the 1992 Rio Declaration on Environment and Development), which indicates that states shouldn't wait until they know exactly how bad a problem is before acting. Research shows that the earlier we act on environmental problems involving uncertainty, the better (European Environment Agency, 2013). This is corroborated by Legal analysis produced by Cornerstone Barristers in 2025, which found that states have a legal obligation to include aviation’s non-CO2 emissions (contrails) in their national climate plans to comply with commitments under the Paris Agreement.
This is why we advocate for greater action on the part of Governments, starting with the inclusion of contrails in net zero legislation and policy frameworks, but also on the part of airlines and other actors in the aviation industry, through support for research and participation in contrail avoidance trials.
Please sign our petition to the UK Government here. This demands that UK legislation and policy frameworks be updated as soon as possible to reflect the climate impact of contrails. It also demands that the Government follow the advice of the Contrail Impact Mitigation Task and Finish Group in establishing a permanent governance body to govern the regulation of contrails: “Government should establish a permanent UK-led body to own this roadmap, coordinate trials, and synchronise learning across the industry.”
2. On the uncertainty surrounding the efficacy of contrail avoidance and the dangers of inaction
We also acknowledge the current uncertainty surrounding the efficacy of contrail avoidance, particularly regarding the meteorological mapping of Ice Supersaturated regions (ISSRs) and the operational difficulties associated with rerouting flights.
However, according to a 2025 report by the International Council on Clean Transportation, contrail avoidance is not only modelled to be the best solution available for contrail mitigation, but also that it is “the most impactful and cost-effective lever” for aviation’s climate impact in general, “accounting for 40% of total avoidable warming by 2050... even with a maximum level of GHG (greenhouse gas - CO2) mitigation between now and 2050, aviation would more than double its share of the remaining climate budget, from 4% of historical temperature change in 2019 to 9%. This highlights the need to identify additional mitigation levers, such as SLCP (Short-lived Climate Pollutants - contrails) control and explicit air transport demand management" (see our position on air transport demand management below).
In addition, a paper produced earlier this year by the University of Cambridge and Imperial College London found that the biggest risk associated with contrail avoidance is not the negligible extra CO2 emissions (see our position on CO2 below) it would produce but rather inaction. Another paper recently found that this was true regardless of what metric is used to quantify contrail warming. Furthermore, there have been a number of successful contrail avoidance trials recently, such as the one conducted by American Airlines in collaboration with Google, which resulted in an estimated 67% reduction in contrail warming effects. Lastly, as Sebastian Eastham, Associate Professor in Sustainable Aviation at Imperial College London, points out, the best way to confront the remaining uncertainty surrounding contrail avoidance is through the continuation and increase of trials.
For these reasons, we advocate for the rapid increase in contrail avoidance trials, particularly over the North Atlantic where a lot of the worst warming contrails are formed.
We think it is important to point out that even if contrail avoidance is found to be ineffective or lead to an excessive amount of extra CO2 emissions, net zero legislation and policy frameworks should still be updated as soon as possible to reflect the warming effects of contrails, as this would provide greater incentives for the aviation sustainability transition. Please sign our petition to the UK Government demanding that here.
3. On who/what will pay for contrail avoidance
Estimates suggest that it would only cost an airline around $20 per flight (not per passenger) to implement contrail avoidance or between $1–$2 per tonne of CO₂ equivalent warming avoided. This has led to contrails being christened as the “low-hanging fruit” of climate change. Airlines spend around $900B a year, so this would be less than 0.1% of their expenses. But it’s still not exactly clear where the funding will come from.
Some argue that given the urgency of the climate crisis, the potential of contrail mitigation as a quick (if only partial) solution, and the deadlock faced by the aviation sector on other sustainability solutions like SAF, the speed rather than the equity of the funding process should be prioritised. This would suggest that Governments should foot the bill through taxpayer funds.
Because of our commitment to environmental and social justice, we think it is important to point out that this would probably not be well received by the general public, especially as aviation is such a lightning rod for environmental injustice (see our values section for more information on this).
We are open to comments on this issue and are prepared to shape our position on it to reflect the public’s views. Please let us know here whether you think airlines, their customers (frequent or occasional flyers) or taxpayers (in the Global North or both the Global North and South) should pay for contrail avoidance.
4. On CO2, the importance of collaboration, air transport demand reduction and Heathrow expansion
We acknowledge the work of organisations like Stay Grounded, Bumprints, Transport & Environment, Opportunity Green, Possible, Flight Free UK, Safe-Landing.org and many others which are aiming to reduce the CO2 impacts of the aviation industry. Aviation is a sector which is proving extremely difficult to decarbonise and is therefore projected to account for 19% of the remaining temperature budget if the +2°C limit set by the Paris Agreement is to be avoided by 2050. It is also on course to be the UK’s highest emitting sector by 2040. For this reason, it is important that any attempts to reduce aviation’s non-CO2 effects do not impede efforts to reduce the sector’s CO2 emissions.
Many of the organisations mentioned above, as well as Contrails.org, Blue-lines.org and Plane Sight News, are also working hard on the science, policy and public communication of contrails and contrail avoidance.
We understand the importance of collaboration in this space to ensure that both the CO2 and non-CO2 climate effects of aviation are reduced significantly, fairly and as soon as possible, without negative trade-offs in either direction. We believe this is possible.
Given the urgency of the climate crisis and the severe lack of progress regarding Sustainable Aviation Fuels (SAF) and other CO2 solutions for aviation, we share the Stay Grounded view that growth in the aviation sector (in other words, an increasing number of flights globally) is incompatible with an equitable and timely transition to net zero. Accordingly, we support air transport demand reduction/management measures, such as the fostering of alternative modes of transport.
However, demand reduction would probably not be enough to resolve the issue of contrails. This is because only 3% of flights cause 80% of persistent ('warming') contrails, so depending on where the reduction takes place, this may not lead to any contrail mitigation at all! This is why we believe that measures like contrail avoidance need to be implemented as well and for trials to take place as soon as possible.
Nevertheless, we are fully aligned with demand reduction efforts regarding CO2, which is also why we are opposed to the expansion of Heathrow.
We believe that it is very important that the proposed expansion of Heathrow is rejected, and not just because an expanded Heathrow would represent a major setback for efforts to reduce aviation's CO2 emissions. Heathrow is mainly a long-haul flight hub and many of the worst warming contrails are formed by long-haul flights over the North Atlantic. By some estimates, the North Atlantic accounted for only 5% of the total flight distance flown in 2019 but a massive 10-11% of annual total contrail warming effects. Therefore, with more and more flights flying into and from an expanded Heathrow and inaction on contrails (the UK Government is currently completely passive on this front), the total warming impact of contrails would skyrocket.
5. On our choice of campaigns, and focus on transparency and greater action
Alongside our petition to the UK Government and the consultation template for Heathrow (which will be ready for when the consultation opens), we are also encouraging people to write to high-profile organisations like Arsenal F.C. (sponsored by Emirates, an airline which is severely lagging behind in terms of transparency and action on contrails), commercial airlines, flight search aggregators, the UK Civil Aviation Authority (CAA), and NATS to call for transparency and greater action.
We are calling for more active transparency because contrails remain a largely unknown or completely misunderstood (due to the ‘chemtrails’ conspiracy theory) subject, and active transparency is desperately needed from these organisations to raise public awareness of this issue. This means that airlines and flight search aggregators should make both the CO2 and non-CO2 effects of their flights clear to consumers at the point of flight selection. Google Flights, which follows the guidance of the latest version of the Travel Impact Model by showing both effects separately, is the only organisation (including airlines) to do this:
In February, the CAA published guidance on the emissions information airlines and other booking organisations should provide passengers when booking their flights. However, this framework is only voluntary until April 2027. Also, “the CAA says it will also monitor developments and research on the non-CO2 impacts… so that more accurate environmental information can be provided to passengers.” As stated previously, we believe there is more than sufficient evidence for the warming effects of contrails to justify inclusion in this framework. This is why we are preparing an email template to be used in communications with the CAA which contains this demand. We also hope the Flight Emissions Label currently being developed for the EU by EASA will contain information about non-CO2 effects.
Beyond transparency, we are also encouraging people call for greater action on contrails, particularly by writing to airlines. This is because, according to the report by the Contrail Impact Mitigation Task and Finish Group, airlines are stuck on level 1 of the maturity model devised by the group, lagging behind all other workstreams in the sector. In addition, the UK Government’s Jet Zero Taskforce recently made “a call for the sector to start quantifying the non-CO2 impacts of aviation”. We believe that airlines should be taking more action, contributing more to research and conducting more contrail avoidance trials with the help of Air Navigation Service Providers (ANSPs) and the relevant authorities.
Finally, we are encouraging people to write to NATS, the predominant ANSP in the UK, as it will play a pivotal role in all future contrail avoidance trials over UK airspace and the North Atlantic. It will require cooperation with the UK Government, which we make clear is necessary in the petition. The UK Government’s Jet Zero Taskforce noted recently “that to make progress in contrail impact mitigation, the UK should run a properly designed trial… leveraging the strong geographical position over the North Atlantic.”
Our choice of communication campaigns therefore reflects our belief that the contrail problem will only be resolved when all the key actors (airlines, civil aviation authorities, governments, ANSPs, flight search aggregators) are encouraged to work together to raise awareness of contrails through greater transparency, and take greater action by perfecting solutions like contrail avoidance through more trials. It also reflects our beliefs that the public has the right to know about this issue and have its voice heard on potential solutions.
6. EU Monitoring, Reporting and Verification Scheme (MRV)
We applaud the EU for taking the unprecedented step of creating a compulsory Monitoring, Reporting and Verification (MRV) scheme for flights operating in the continent. However, we share the frustration expressed by other organisations, like Transport & Environment, at the fact that industry lobbying caused the scope of the MRV scheme to be limited to only intra-EEA flights for the first two years of the framework. This means that 67% of non-CO2 effects are not currently being captured by the scheme. We hope that the scheme is extended to its full scope in 2027, as scheduled. We also hope that the scheme will inform sufficient regulatory measures and mandatory trials for contrail avoidance soon.
It is important to point out that the aforementioned legal analysis produced by Cornerstone Barristers suggests that the UK, or any state, should not wait “for further data on [non-CO2’s] climate impact to become available via the MRV framework under the EU ETS” before taking measures to address these effects. This is because of the precautionary principle, enshrined by Article 3(3) of the UNFCCC and Articles 4,7 and 14 of the Paris Agreement.
For this reason, while we praise the MRV scheme as an unprecedented first step to regulating contrails, we believe the EU, UK and any other state with the power to do so, should start legislating for effective contrail regulation as soon as possible.
7. Aviation’s Non-CO2 effects beyond contrails
Aviation’s non-CO2 impact other than contrails includes the effects of Nitrogen Oxides (also called NOx), Soot particles (Aerosols), Sulphur Oxides (SOx), among others. Due to resource constraints, this campaign is not able to concentrate on these other effects.