Workshop on Aviation non-CO2 emissions

13. - 14. December 2023
Breydel building Oudergemlaan 45, 1000 Brussels, Belgium

For over 25 years, successive European aviation Strategic Research and Innovation Agendas set ambitious environmental and climate goals (i.e. ACARE Flightpath 20501) and the achievements are very good. However, only last year, in the latest edition of Europe’s Vision for Sustainable Aviation by ACARE, the importance of all non-CO2 effects was adequately recognised. Given the many parallel initiatives in the last two years, the workshop presents a great opportunity to work even closer together with the industry, airlines, research establishments and academia towards cost-optimum solutions for aviation and climate.


The workshop is organised jointly by the European Commission (DG-RTD, DG-MOVE, DGCLIMA, DG-ENV), including the two aviation Horizon Europe Partnerships (Clean Aviation and SESAR) and the European Aviation Safety Agency.

Content Description

The objectives of the workshop are fourfold:

  • To provide an overview of the state-of-play of aviation non-CO2 impacts, notably:
    • Dependence of contrails on altitude and geographic region
    • Predictive accuracy of met conditions that promote persistent contrails
    • Sensors on-board
    • Satellite contrail detection & tracking - overestimation of persistent contrails
    • Percentage of flights that are really affected in Europe and globally
    • Expectations from hydrogen-powered aviation and water-enhanced turbofan
    • Impact of SAF on contrails
    • Can simplified calculation methods be trusted and verified?
    • Climate restricted airspaces
    • Metrics for CO2 and non-CO2 aviation emissions - AGTP - ATR100 or what?
    • ATM trade-offs for CO2, NOx and contrails
    • Can the complexity of non-CO2 emissions be represented by a CO2 multiplier?
  • To listen to all relevant stakeholders, identify research and policy gaps, and gather
    recommendations, that have the potential to actually reduce the aviation non-CO2
    impacts, mainly via new technologies and optimised operations, in the short- and
  • To contribute to a quantified and scientifically-agreed roadmap towards minimising
    all non-CO2 aviation impacts towards 2050 (and 2070), considering all possible
    measures (i.e. new technologies, optimised operations, new fuel options, and market-based measures) in combination as well as the trade-off between CO2 and non-CO2 emissions. The workshop is confined primarily to the climate effects of non-CO2 aviation emissions, while Local Air Quality (and noise) will be the subject of an upcoming workshop in Q3 2024.
  • To communicate the findings of the workshop and contribute towards clearing the fog that surrounds the issue, for the benefit of aviation and the climate.


Day 1

  • 9:00 Registration and Welcome Coffee/Tea
  • 9:30 Opening Address
    DG RTD / Roselinde van der Vlies, DG CLIMA / Bea Yordi
  • 9:45 Session 1 - Non-CO2 Aviation Emissions/Impacts - State-of-the-art
    Chair: Michael Kyriakopoulos (DG RTD)
    • Keynote: 25 years of non-CO2 aviation emissions research after Seeheim
      DLR & TU Delft / Volker Grewe
    • Better contrail understanding and mitigation options
      DLR / Christiane Voigt
    • Aircraft and engine influence on CO2 and non-CO2 emissions
      Airbus / Charles Renard
    • Q&A (10 min)
  • 11:30 Coffee Break
  • 11:45 Session 1 - Continued
    • Progressing toward a better estimate of the climate impact of aviation
      ISPL & ONERA / Nicolas Bellouin, Philippe Novelli
    • Climate assessment of single flights
      DLR / Katrin Dahlmann, Sigrun Matthes
    • Significant factors influencing the net effect of single contrail
      Technische Universität Dresden / Judith Rosenow, Hartmut Fricke
    • Q&A (10 min)
  • 13:00 Lunch Break
  • 13:45 Session 2 - Innovative Technologies I
    Chair: Niclas Dzikus (DG-RTD)
    • Expectations from hydrogen-powered aviation
      Airbus / Glenn Llewellyn, Frédérique Rigal
    • Challenges and non-CO2 impact of hydrogen-burning engines
      Rolls-Royce / Paul Madden
    • Multi MW fuel cell systems – challenges and potentials
      MTU / Dominik Wirth
    • Current knowledge of the impacts of NOx
      IPSL & ONERA / Didier Hauglustaine and Etienne Terrenoire
    • Q&A (10 min)
  • 15:15 Coffee Break
  • 15:30 Session 2: Innovative Technologies II
    Chair: Jean-Francois Brouckaert (Horizon Europe Clean Aviation)
    • A significant reduction in NOx emissions
      SAFRAN / Valérie Guenon, Nicolas Jeuland
    • The Water-Enhanced Turbofan - A revolutionary gas turbine concept
      MTU / Christopher Pfennigs
    • Low NOx Technologies
      GE Aerospace / Thomas Ripplinger
    • CS2 Technology Evaluator and CA ACAP Impact Monitor
      Airbus / Matthias Meussen
    • Q&A (10 min)
  • 17:30 Discussion
  • 18:00 Close Day 1

Day 2

  • 9:00 Registration and Welcome
  • 9:30 Opening Address
    DG MOVE / Filip Cornelis
  • 9:45 Session 3: Market-Based Measures - EU-ETS - MRV
    Chair: Dimitar Nikov (DG-CLIMA)
    • Regulatory/Certification issues related to EU-ETS Directive Art 30(4)
      EASA / Joonas Laukia
    • Tender CLIMA/2023/OP/0005 - Support for establishing an MRV system
      for non-CO2 effects in aviation - revision of the ETS Directive
      To70 – DLR - AerLabs / Liam Megill
    • Climate metrics for aviation CO2 and non-CO2 impacts: technical and policy
      Airbus / Philippe Mattei
    • Aviation Impact Accelerator on fleet impact of new technologies
      University of Cambridge / Rob Miller
    • Q&A (10 min)
  • 11:15 Coffee Break
  • 11:30 Session 4: Fuel Options
    Chair: Andreas Busa (EASA)
    • Unveiling nucleation mechanism in aircraft engine exhaust and its link
      with fuel composition options
      ONERA / Ismael Ortega
    • Cleaner aviation fuels have the potential to reduce contrail cloudiness
      DLR / Patrick Le Clercq, Tina Jurkat-Witschas, Christiane Voigt
    • A full environmental life cycle assessment (eLCA)
      BHL / Mirko Hornung, Andreas Sizmann, Valentin Batteiger
    • Energy Transition in Aviation – future fuel options
      TU Delft / Arvind Gangoli Rao
    • Q&A (10 min)
  • 13:00 Lunch Break
  • 13:45 Session 5: Optimised Operations I
    Chair: Andrei Mungiu (DG-MOVE)
    • Towards Climate-Optimized Operations
      THALES / Julien Lopez
    • Mitigation strategies studied in the ClimOP project
      NLR / Elisabeth van der Sman
    • Satellite and ATC data for contrail detection, tracking and matching
      Airbus/ Remi Chevallier
    • Satellite detection of contrails using AI and changes COVID-19
      DLR / Luca Bugliaro
    • Q&A (10 min)
  • 15:15 Coffee Break
  • 15:30 Session 5: Optimised Operations II
    Chair: Olivia Nunez (Horizon Europe SESAR)
    • CICONIA - Climate effects reduced by Innovative Concept of Operations
      Airbus / Philippe Mattei
    • CONCERTO – Traffic Flow optimizations based on total climate impact
      THALES / David Antonello
    • MUAC Contrails prevention – the global picture and main challenges
      EUROCONTROL / Ilona Sitova, Rüdiger Ehrmanntraut
      ContrailHub® - Sharing contrails data to facilitate research
      EUROCONTROL / Philippe Very, Gabriel Jarry
    • Actual and Time-Optimized Flight Trajectories
      KLM – Air France / Lisanne van Wijngaarden
    • Q&A (10 min)
  • 17:00 Conclusions - Discussion Panel
    Moderated: Michael Kyriakopoulos (DG RTD)
  • 18:00 Workshop closure