I don't work in commercial aviation any more, but can offer a few pointers
Eurocontrol are exactly the people you want taking this seriously - they regulate European airspace. So whilst I think it probably is neglected relative to other climate proposals in terms of funding vs estimated impact, it may not be neglected by the right people.
For related reasons, I think it's way more tractable than most interventions: changing altitude under certain conditions is a lot easier than dissuading people from flying or consuming. And there is an established track record of regulators enforcing environmental rules and costs like noise restrictions and NOx emissions charges (along with sticks governments haven't beat them with yet like carbon taxing jet fuel)
On the other hand it seems like it's actually true the current state of scientific consensus hasn't resolved the important question of when and where to divert yet (see the variability factors in your infographic) and the diversion usually does result in increased fuel burn (and some contrails are even cooling!) And flight directions are a complex multidimesional problem
Airspace controllers will need to be involved because airlines are unlikely to do anything voluntarily that impacts their profit margins (which are on average small anyway) regardless of how settled the science. In general, being "greener" through lower fuel consumption actually saves them money; this is an obvious exception.
An indirect "stick" approach like levying fines or additional charges on airlines causing contrails whilst passing through particular airspace sounds neat, but whilst theoretically contrails observed from the ground or orbit can be matched to ADS-B readings of aircraft that recently passed through that space, systematically validating that in a legally-valid way in congested airspace seems tricky...
I can't see it being practical to achieve via consumer pressure and wider public awareness campaigns run the risk of getting mixed up with "chemtrails" conspiracy theories
If you want a possible exception to airline lack of sympathy, a UK startup airline Zeroavia is owned by eco-activist billionaire Dale Vince. Their hydrogen powered fleet claims they already intend to capture water emissions to release at lower altitude [1] for the stated purpose of avoiding contrails. Zeroavia are a very atypical airline, currently have zero flights and I'm not sure how much aviation industry executives actually respect Dale, but if you wanted to outreach to an airline that actually might be sympathetic and see PR benefits of shouting about contrails, they'd be a starting point
So I think there's definitely something to be worked on here, but its going to take industry experts more than grassroots campaigning. I think there are probably some really interesting algorithm development projects there for people with the right skillsets too...
(For anyone interested in space, an analogous situation is the aluminium oxide deposited in the mesosphere by deorbiting spacecraft. This used to be negligible. It isn't now that constellations of 10s of 1000s of satellites with short design lives in LEO are a thing. The climate impact is uncertain and not necessarily large but probably negative; the impact on ozone depletion could be much more concerning. Changing mindsets on that one will be harder)
This is the third in a sequence of posts taken from my recent report: Why Did Environmentalism Become Partisan?
Summary
Rising partisanship did not make environmentalism more popular or politically effective. Instead, it saw flat or falling overall public opinion, fewer major legislative achievements, and fluctuating executive actions.
Public Opinion...
I think right now EAs might be making a significant mistake by paying insufficient attention to the political realm. As EAs we tend to figure out what’s most impactful for us to work on and focus hard. That’s great! But there are various actions that are ‘non-delegatable’ - the extent to which an individual can do the action is limited (like voting, going to a protest, making hard money contributions to particular campaigns). It might be useful if we were all more in the habit of doing variou...
This post presents the executive summary from Giving What We Can’s impact evaluation for 2025. At the end of this post we share links to more information, including the full report and...
There could be a major, overlooked climate opportunity: avoiding persistent contrails caused by aircraft. These contrails can form cirrus-like clouds trapping as much heat as all historical aviation CO2 emissions. The IPCC and other experts confirm contrails significantly warm the planet, even if the exact figure is uncertain. The good news is that changing flight altitudes by roughly 2,000 feet to dodge high-humidity zones could dramatically reduce contrail-induced warming. Making this change for contrails could cut the climate impact of aviation in half, at very low cost. This strategy is comparable to how airlines already reroute around turbulence.
Studies from Breakthrough Energy and Imperial College suggest that contrail avoidance might cost as little as $1–2 per metric ton of CO2-equivalent— below the $10/ton estimates of avoided climate damage from Clean Air Task Force and the Coalition for Rainforest Nations (source: Founders Pledge). Such a low-cost, high-impact measure may beat almost all other large-scale mitigation efforts. Yet airlines have not embraced it, citing scientific uncertainties. This hesitation recalls fossil fuel companies’ historical stalling. Acting now on contrail avoidance could be a top priority: it’s cheap, scalable, visible, and can reduce near-term warming. Could we deploy a policy campaign to make governments pay airlines to implement these altitude adjustments? Or is there another way to capture this low-hanging climate solution and significantly reduce our collective climate footprint?
We can do a simple analysis using the ITN framework:
Importance: yes!
According to Our World in Data, "Although CO2 gets most of the attention, it accounts for less than half of this warming. Two-thirds come from non-CO2 forcings. Contrails — water vapor from aircraft exhausts — account for the largest share. This explains why aviation contributes 2.5% of annual CO2 emissions but more when it comes to its total impact on warming."
Since about half of the temperature increase of the aviation industry is from contrails, avoiding 70% of this would be equivalent to cutting annual CO2 emissions by 1.75%! While this may not sound like much to the uninitiated, those in the climate space will understand what a massive deal this would be.
For those who want more depth, you can check these graphs from relevant science papers (1, 2) showing how paying a negligible increase in the cost of around 2-3% of all flights globally would reduce more than 70% of the total contrail radiative forcing of the aviation industry. The 80/20 rule at work:
Another fun tidbit from this article: preliminary work suggests eliminating contrails could reduce European summer warming by about a third.
Tractability: unsure
Despite the estimated ease and relatively low cost, no major airlines are currently avoiding contrails. Uncertainty around the exact impact of contrails is an oft-cited reason. Overall, the biggest factor underlying delay is that little economic motivation exists at this time for airlines to avoid contrails, and commercial airlines are obligated to try to maximize return to their stockholders. How can this be changed?
The tractability of this depends on exactly the intervention you would like to implement to realize this. As a person working on a different field, I will not venture a guess as to how tractable different interventions might be. Would it be best to mount a policy campaign to influence the US government? Or the EU? Or the UN? Liaise with aviation industry associations? Work out a startup that raises funds as a step in flight purchase to implement a web-based solution financed by flying customers? Something else? I'm curious to hear ideas from those working in the space.
Neglectedness: maybe not?
My first step before deciding to write this was going on the forum to see if someone had discussed this. I only found this great comment by user MatthewDahlhausen, part of which reads:
If I had to pick interventions in the aviation space that are likely underfunded, I'd focus on atmospheric research to better predict and understand the impact of contrails on radiative forcing, and real-time aircraft re-routing / altitude adjustments to reduce contrail formation. One could image an extension of air-traffic control that uses contrail formation risk to direct planes much as they do with real-time weather data for flight risks and to avoid turbulence.
So, at least Matthew who works at NREL[1] thinks it's underfunded. That might have pushed me on the edge of actually writing this short post here.
Who might already be working on this? Results from a cursory search:
Breakthrough Energy has a contrails project at least from the modeling side, and they have the weight of the Gates Foundation behind them.
RMI’s Contrail Impact Task Force is "at the forefront of advancing solutions for the warming effect of these aviation-induced clouds". They have a great diagram of the phenomenon which I put at the start of the post.
So there clearly already is some significant effort being invested into this. With that in mind, what matters is how contingent you think contrail mitigation is, how likely it is to happen without further action. If anyone has reason to think that this will eventually get fully solved by the people already working on this, the value of getting involved is marginal. If on the other hand you think this is unlikely to realize its full potential without additional people pushing on this, that could be a reason to jump in. I'm curious to hear if anyone has thoughts around this.
Thanks for the very interesting post.
I don't work in commercial aviation any more, but can offer a few pointers
So I think there's definitely something to be worked on here, but its going to take industry experts more than grassroots campaigning. I think there are probably some really interesting algorithm development projects there for people with the right skillsets too...
(For anyone interested in space, an analogous situation is the aluminium oxide deposited in the mesosphere by deorbiting spacecraft. This used to be negligible. It isn't now that constellations of 10s of 1000s of satellites with short design lives in LEO are a thing. The climate impact is uncertain and not necessarily large but probably negative; the impact on ozone depletion could be much more concerning. Changing mindsets on that one will be harder)
which sounds seriously expensive to me....