The International Air Transport Association (IATA) called for urgent action to deepen the understanding on the formation and climate impact of aviation contrails to develop effective mitigation measures.

The newly released IATA report Aviation Contrails and their Climate Effect: Tackling Uncertainties and Enabling Solutions calls for a strengthening of collaboration between research and technological innovation, coupled with policy frameworks to address aviation’s non-CO2 emissions through more atmospheric data.

The report highlights the complexity of contrail science, noting gaps in the understanding of how contrails form, or when they could persist, and how they impact the climate.

The lack of high-resolution, real-time data on atmospheric conditions (particularly humidity and temperature at cruising altitudes) hinders precise contrail forecasting.

“The industry and its stakeholders are working to address the impact of non-CO2 emissions on climate change, particularly contrails. To ensure that this effort is effective and without adverse effects, we must better understand how and where contrails form and shrink the uncertainties related to their climate impact. “Action now” means more trials, collection of more data, improvement of climate models, and maturing technologies and operations. Formulating and implementing regulations based on insufficient data and limited scientific understanding is foolish and could lead to adverse impacts on the climate. That is why the most important conclusion from this report is to urge all stakeholders to work together to resolve current gaps in the science so that we can take effective actions,” said Willie Walsh, IATA’s Director General.


With current levels of understanding, the report made the following recommendations:

• In the immediate term (2024-2030), the priority for mitigating aviation’s climate change impact should be on reducing CO2 emissions over the uncertain gains that could stem from contrail detection and their mitigation. Over this time, increasing airline participation in sensor programmes, continuing scientific research, and improving humidity and climate models should be the focus of work on contrail mitigation.

• Mid-term actions (2030-2040) should involve establishing standards for data transmission, continuous validation of models, and encouraging aircraft manufacturers to include provisions for meteorological observations, as well as selected avoidance.

• Longer-term actions (2040-2050): Aircraft should be continuously providing data and the models and infrastructure should be there and be reliable. The community will have at this point a more complete understanding of the non-CO2 effects of alternative fuels, with extended mitigation measures. These action items collectively aim to mitigate the climate impact of aviation while advancing scientific understanding and technological capabilities.
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