Wildfires, low water levels, and shifting travel habits have dominated this summer’s climate coverage, but I’m bringing you something a little different this week: contrails. 

Condensation trails, known as contrails, are ice clouds that form behind aircraft. They occur when soot and water vapor emitted by jet engines mix with cold, humid air at high altitude, creating artificial cirrus-like clouds. 

Sometimes they dissipate quickly, but those that linger typically have a warming effect because they trap heat in the atmosphere, depending on the time of day and year. For this reason, it’s likely that aviation’s contribution to climate change is much higher than the well-cited stat of 2–3% of global carbon dioxide emissions. 

The good news is that work is underway to understand and predict where they will form, which means those areas can be avoided. It may not be hugely disruptive either: researchers think it can be done by rerouting a flight up or down just 2,000 meters, within existing air traffic control protocols. 

Contrail avoidance is an area of active research, and today a UK-based and backed consortium of technology partners and researchers announced a £5 million project to test out that hypothesis.

Google UK, the UK Department for Transport, the Met Office, NATS and Contrails.org will run an airspace-wide contrail avoidance operation over two winters across the NATS-controlled Shanwick airspace, starting this year. Shanwick is a particular hotspot for contrail formation and has high traffic, meaning any positive results could be a win for climate action.

Imperial College London and the University of Cambridge will analyze and independently verify the operation’s findings. 

Check out my full reporting over at Skift, and, as ever, feel free to say hi at [email protected].