The 42nd ICAO Assembly opens in Montreal
23rd September, 2025
Today, Tuesday 23rd September, sees the start of the International Civil Aviation Organisation’s (ICAO’s) 42nd session of the Assembly. Held every three years at its Montreal headquarters, the Assembly of this United Nations specialised agency brings together 193 member states to discuss all aspects of international air travel including safety, security, navigation and environmental issues.
Environmental NGOs have been attending ICAO meetings since 1998, when several organisations, including AEF, formed a coalition (the International Coalition for Sustainable Aviation, or ICSA for short) and applied to be recognised as an observer. Since that day, ICSA has actively participated in the technical working groups of ICAO’s environment committee and has played a vocal role in Assembly negotiations on climate and noise goals for the sector.
So what can we expect in 2025?
At the last Assembly in 2022, ICAO agreed an aspirational goal for international aviation to be net zero by 2050. Twelve months later, it supplemented this with a declaration that aimed for a 5% reduction in emissions from international aviation by 2030 to be achieved through the use of alternative non-fossil fuels, and earlier this year it agreed tougher CO2 and noise standards for aircraft and engine manufacturers. The Secretary General has said that the theme of this Assembly should be a focus on consolidation and implementation of these decisions.
This implies that it’s unlikely that new environmental matters of significance will be brought to the table for a decision, but ICSA has tabled a working paper for the Assembly that stresses the importance of not standing still. We simply don’t have time to pause: rolling issues over to the next Assembly in 2028 would mean a big gap of six years. ICSA is, therefore, requesting the Assembly to think about how it can prepare for the future and has proposes three actions:
1. ICAO has aspirational goals to keep net emissions from international aviation at or below 2020 levels, and as mentioned, to be net zero by 2050. But there is no agreed pathway to join these goals. This makes benchmarking ICAO’s progress difficult and risks the sector being off track. Setting interim goals for the 2030s and 2040s would address this issue, and ICSA is asking the meeting to undertake the work necessary to support a timely decision.
2. Since the last Assembly, there has been real momentum on how to address non-CO2 impacts, especially contrails. These impacts are currently outside of ICAO’s goals, but the latest scientific assessments conclude that their climate impact has been double that of aviation’s CO2 emissions to date. With many stakeholders turning their attention to how to avoid contrail formation, further progress is expected in the coming years. ICSA is seeking a change to the Assembly’s Resolution on Climate Change to better acknowledge these impacts.
3. Drawing these two strands together, ICSA member ICCT, the International Council for Clean Transportation, has updated the ICSA vision which sets out a pathway to net zero. In an updated analysis published in an ICCT paper, ICSA presents an integrated analysis of CO2 and non-CO2, showing the temperature response associated with various mitigation levers. Interestingly, this demonstrates that non-CO2 controls can provide faster and cheaper reductions in Earth’s temperature response to international aviation activity than CO2 controls. ICSA is calling on ICAO to undertake a similar analysis to better understand future mitigation and policy priorities.