A4Climate

A4Climate is a European research project dedicated to reducing the climate impact of aviation by tackling one of its most uncertain and potent contributors: non-CO₂ effects, especially contrails. Funded under the Horizon Europe programme, the project brings together 17 partners from across academia and the industry to generate new scientific knowledge, develop cutting-edge prediction tools, and demonstrate real-world mitigation strategies.

Through advanced laboratory and in-flight measurements, A4Climate investigates how modern engines and sustainable aviation fuels influence contrail formation. It also tests climate-optimized flight routing in over 400 commercial flights and improves weather forecasts to better predict contrail-prone regions. The results feed into open-access software and evidence-based policy recommendations to support the EU’s climate targets and non-CO₂ regulations.

By combining science, innovation, and stakeholder engagement, A4Climate aims to make climate-friendly aviation a reality—starting now.