Contrails – Plane to see

(EurActiv, 2 May 2024) If you look up at a clear blue sky you’ll surely already have seen white stripes criss crossing the horizon. Contrails, as these stripes are called, are caused by jet engine exhaust. They are worse for the climate than aviation’s CO2 emissions.

William Todts is Executive Director of Transport & Environment

Cutting contrails is the quickest, cheapest path for the airline industry to reduce its climate impact. Yet some legacy airlines and other players in the industry are lobbying hard to avoid this from happening.

Contrails are formed when particles emitted by planes combine with water in ice cold and humid parts of the atmosphere. These little ice crystals are the stripes we see when we look up. Some contrails form clouds which can last in the atmosphere for up to a few hours. When the sun goes down, they trap heat coming from earth, warming the planet.

If it were just one flight, the impact of contrail-induced heating would be insignificant. But as there are more than 20,000 daily flights crossing over Europe alone, contrails clouds become semi permanent, leading to very significant warming. 

This phenomenon was described in a landmark IPCC report published in 1999 – a quarter of a century ago. Since then, regulators across the world have done nothing to address contrail pollution. For that, we can thank the aviation industry.

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EurActiv, 2 May 2024: Contrails – Plane to see