These trails, made up of water vapor and soot freezing at high altitude, form cloud veils acting as a greenhouse gas. “It’s like a blanket that prevents the Earth’s heat from escaping into space,” Carlos López de la Osa, a specialist in aviation durable within the NGO Transport & Environment (T&E).
They form in cold and humid regions (supersaturated with ice, or “ISSR”), the avoidance of which could greatly reduce the climate impact of the sector, scientists estimate.
In Mérignac, in the Bordeaux metropolitan area, the aeronautical equipment manufacturer Thales is developing solutions in this direction: connected aircraft controls, flight calculatorclimate footprint of each flight, “orchestrator” software connecting air control zones…Such as this FlytX cockpit with large touch screens: on a Sion-Dublin flight simulation, the pilot is able to receive an alert before or after the take-off, validate a new flight plan and avoid an area with the agreement of air traffic control.
Divert the planes
Contrails could account for up to 57% of aviation’s warming impact, far more than CO2 emissions from fuel combustion, according to a 2021 study published in the scientific journal Atmospheric Environment .
“They represent the hidden part of the iceberg,” summarizes Matteo Mirolo of Breakthrough Energy, American tycoon Bill Gates’ initiative to fight climate change.
And avoiding them seems within reach: only 2 to 3% of thefts “create 80% of condensation trails warming,” he notes. A recent T&E study suggests a possible halving of this impact “by slightly modifying the flight paths of a small part of the global fleet.”
It remains to identify these flights and divert the planes concerned, as a handful of companies are already testing, including American Airlines and Amelia in France.
The small regional company has started tests: out of around thirty Paris-Valladolid flights, five saw their trajectory modified at the cost of a slight additional cost of kerosene, explains Adrien Chabot, director of innovation, pleading for a generalization of this practical.
“I don’t see today what could prevent” the big companies from doing the same, he said, while admitting a “financial issue“.
Amelia uses Flights Footprint, a Thales calculator based on the latest weather modeling and artificial intelligence. This application makes it possible to measure the climatic impact of a flight by also integrating non-CO2 effects such as condensation trails.
“These are things that can become realities relatively quickly,” assures Denis Bonnet, vice-president in charge of research, technology and innovation for aeronautics at Thales.
“We need regulations”
But air traffic controllers “don’t like at all” when trajectories are changed, he emphasizes. “When we do (avoidance) in a non-collaborative way, it saturates the system.” For this, the equipment manufacturer has also developed an “orchestrator” so that pilots and controllers agree on the area to avoid and so that traffic can be reorganized.
Despite these innovationssome players in the sector consider it necessary to wait. “I don’t think we are ready,” argues Nelly Elguindi, manager of non-CO2 emissions at Iata, the association of major airlines.
She suggests collecting “more data” to ensure that avoidance, which she nevertheless considers “promising”, does not generate more of a warming effect than it eliminates: “Certain contrails have “We don’t want to deviate from flights producing cooling contrails, emitting more CO2 to do so,” she says.
“These uncertainties should not justify inaction,” replies Matteo Mirolo of Breakthrough Energy, emphasizing that the scientific consensus is that the trails “as a whole” have a “significant” warming effect.
“The industry does not have enough pressure to act,” says Carlos López de la Osa. “Regulations are needed for these solutions to be deployed on a large scale.”
On January 1, the European Commission must set up a mechanism pushing companies to monitor their non-CO2 impact, regarding flights between European airports. Brussels must then submit a report by the end of 2027 in order, “if necessary”, to formulate regulatory proposals.
With AFP.
