Earth Day 2025, April 22, marked the two-year anniversary of Blue Lines (🎂 🎶 happy birthday to us 🎶 🎉), so I wanted to take this time to reflect on results so far and things to come.

Some highlights in the first 24 months of Blue Lines:

• Created the educational website blue-lines.org

• Created and still maintains the Airline Contrails Index, tracking airline involvement with contrails

• Co-authored and co-edited the RMI-report, Understanding Contrail Management

• Started and grew Blue Lines’ contrails newsletter (and LinkedIn profile) to currently well over 1000 subscribers

• Co-founded and co-organized the Copenhagen Contrails Conference

• Worked on contrail-related communication and tools with Breakthrough Energy / Contrails.org, Google, and others.

• Plus: Has spoken and moderated contrail-related sessions at aviation conferences and events in the US and Europe, co-launched a contrails communications group, and tirelessly attempted to make journalists cover contrails, their climate impact, and the solutions to avoid them.

This list clearly shows that collaboration and cooperation are key. Only a few people work in the contrail space (compared to, for example, SAF), so working together and helping each other are key.

Looking forward, the coming year is very interesting. At Blue Lines, we are especially interested in two tracks:

1. How do we ensure the climate solution of contrails gets on more people’s radars? Especially when the results of the European Monitoring, Reporting, and Verification (MRV) of contrail warming (and other non-CO2 effects) are publicised in early 2026, meaning that travelers will “discover” that the climate impact of flying is even greater than they thought.

2. How do we get airline executives to participate in contrail avoidance trials at scale? As it is now, airlines are incentivized to do nothing (more about this in a later newsletter). We need to change that.

If these two questions are something you are working on, I would love to get in contact and collaborate.

Video appetizers from the Copenhagen Contrails Conference

A couple of weeks ago, we started posting small video bites on LinkedIn of key messages from some of our best speakers at the Copenhagen Contrails Conference. This could act like a teaser for folks to watch the entire talk (all day 1 talks from the conference were filmed and are available here) and get more people engaged in contrail mitigation.

Below you can watch the first three contrail snacks:

Why might contrails be the most visible effect humans have on climate?

Professor Marc Stettler broke it down in his excellent contrails masterclass at
the Copenhagen Contrails Conference.

Watch the entire presentation here.

Contrail warming is at least 100 times bigger than the CO2 emissions from the extra fuel needed to eliminate most contrails

One persistent myth in contrail management is that the CO2 emissions from the extra fuel needed to fly around the contrail-prone areas could outweigh the climate benefit of avoiding those contrails.

In this clip from the Copenhagen Contrails Conference, AIA director Paul Hodgson explains why the fuel burn penalty (around 1% extra fuel) is at least 100 times smaller than the contrail warming.

Let’s stop treating a rounding error as a roadblock.

Watch the entire presentation here.

The 5️⃣ steps to communicating contrails to anyone

🛫 Contrails are complicated. But here is a brilliant, five-step narrative that can be used to tell family, media, or even policymakers about contrails. This recipe was presented by Diane Vitry, interim aviation director at T&E, at the Copenhagen Contrails Conference:

1. Contrails are a visible problem 👀
2. They warm the planet significantly 🔥
3. Their climate impact can be explained ❄️
4. Contrails can largely be avoided 🛩️
5. Fixing them is inexpensive 💰

Watch the entire presentation here.

Go to Blue Lines’ educational website to explore contrails in depth.

(As regular readers of the Blue Lines newsletter know, contrails are the thin white streaks that airplanes sometimes leave behind in the sky, created from water vapor and engine soot. Some of these condensation trails can spread out and form high-altitude ice clouds (cirrus), which reflect some of the sun’s energy back into space while also trapping outgoing energy in the atmosphere, leading to a net warming of our planet equivalent to 1-2% of human-induced global warming. However, studies and trials indicate that it is relatively simple to avoid most warming contrails by flying around areas in the atmosphere that are prone to contrails. This climate solution—often referred to as contrail management or contrail avoidance—is what Blue Lines advocates for and hopes to see implemented globally.)

See you soon.

Joachim Majholm,

Blue Lines