Countries gather for triennial ICAO Assembly, with a focus on CORSIA and SAF scale-up

After a series of sessions marked by big announcements on the environmental front, ICAO’s 42nd Assembly starting on September 23 will instead focus on stocktaking and implementation. Despite the change, the Assembly will still be closely watched. Two themes are poised to dominate the environmental discussions: fixes to ICAO’s CORSIA (the Carbon Offsetting Reduction Scheme for International Aviation) and the scale up of sustainable aviation fuels. In the background, there could also be governance talks over the non-ICAO proposed international aviation climate levies, or the credibility of 2050 targets without interim objectives. Justine El Amrani-Joutey of Ishka SAVi takes a deep dive into what states, industry groups and NGOs are set to advocate for in Montreal, three years after the adoption of ICAO’s long-term global aspirational goal (LTAG) for international aviation to achieve net-zero emissions in 2050.

Several working papers (all working papers are available on the A42 website) converge on a simple operational risk: airlines’ offsetting obligations under CORSIA began with 2024 emissions for Phase 1 participants, but the supply of Eligible Emissions Units (EEUs) is lacking, due in large part to host states not issuing the Letters of Authorisation (LoAs) to apply corresponding adjustments to their emissions balance. As of mid-September 2025, Guyana remains the only country to have issued EEUs.

Representing airlines, IATA (WP/322) is urging states to “promptly issue LoAs” and expand voluntary participation before 2027, arguing scarcity will drive price volatility and compliance risk. The Arab League-affiliated Arab Civil Aviation Organisation (ACAO) (WP/295), which counts 22 members, makes the same point and asks for accelerated LoAs and adjustments to stabilise supply.

Other less existential CORSIA demands also flare up. For instance, Pakistan warns the sectoral growth factor– a key parameter used in CORSIA to determine aircraft operators’ offsetting obligations – is expected for the first time to be positive for 2024, as international aviation surpasses the 85%-of-2019 traffic threshold. The precise number will be published by ICAO before the end of October 2025.

Pakistan’s paper contends this would bring disproportionate costs for operators in developing states, and asks ICAO to broaden the CORSIA-Eligible Fuels (CEFs) SAF feedstock criteria to include feedstocks Pakistan can easily access. India, on the other hand, flags a practical regulatory gap, alleging there is no guidance on how to calculate CORSIA baselines and obligations through mergers, demergers and acquisitions – a question sparked by the Vistara-Air India merger in 2024.

A big question mark on CORSIA is also the role of the US. The country walked away from the International Maritime Organisation (IMO) talks on its net-zero framework in April, and urged other IMO members to reconsider their support – threatening retaliatory measures against those that backed the plan. In preparation of the 42nd Assembly, the country has not published any papers under the environmental items. Tim Johnson, Director of the UK-based Aviation Environment Federation (AEF), and who also represents international NGO coalition group ICSA at ICAO, says everyone is aware of the IMO incident, but he believes the country “will remain committed to ICAO, […] there’s a clear rationale for the US to want to be at the table when you look at Boeing’s global interests and the need for international standards.”

Expected pushback on aviation carbon pricing and levies outside of ICAO

The fault line over who gets to regulate aviation emissions is set to resurface in Montreal. On top of ICAO’s long-running opposition to the EU ETS, 2025 saw the rise to prominence of the Global Solidarity Levies Task Force (GSLTF), an international initiative studying climate levies for polluting sectors. The GSLTF, which is backed by a handful of small countries together with France, Kenya and Spain, and supported by the European Commission, formally established in June a coalition for levies on premium flyers, with the explicit aim of building momentum for new taxes on aviation.

ICAO has made clear it views such initiatives as a direct challenge to its mandate as international aviation’s regulator and its capacity to stimulate global action. In its own working paper (WP/26), the Council of ICAO notes it has been “closely following” proposals under consideration emanating from outside its remit, and warns they remain “under active discussion despite concerns raised by ICAO across various platforms.”

The Council argues that aviation levies risk raising travel costs for small island and tourism-dependent states, “undermining the economic viability of airlines and delaying progress” towards multiple UN Sustainable Development Goals. The paper reiterates that CORSIA is the only agreed global market-based mechanism (MBM) for international aviation, and calls on states to “continue to express clear concern” about diverting sectoral resources to other purposes.

This message is echoed across a bloc of state and industry submissions. The African Union-affiliated African Civil Aviation Commission (AFAC) (WP/122) and ACAO(WP/295), representing a combined 75 states, re-affirm CORSIA as the sole global MBM, warning that regional schemes such as the EU/UK ETS and any solidarity levies could result in double counting and duplicative obligations that drain capital from decarbonisation. IATA (WP/322) also argues that fragmented MBMs “double charge the same tonne” and take away funds from SAF and offsets.

Haldane Dodd, Executive Director of the Air Transport Action Group (ATAG), which represents OEMs and key aviation trade bodies, says he believes the levies “will come up”, though he is not sure “how much of a discussion there will be.” Dodd questioned why the GSLTF decided to “look at aviation at this stage as opposed to other sectors” as he sees “options for levies to be looked at in other sectors, including cryptocurrencies, or oil and gas.”

Johnson, on the other hand, believes discussions on the levies could act as “disruptors”. He specifies that states may regard the GSLTF proposals as “an aggressive action on their airlines, [..] and may seek to use this [Montreal] as an opportunity to say ‘don’t do it; we are warning you don’t do it.’ What may happen if they went ahead, you can’t really speculate,” he shares. Johnson notes that technically, the proponents of the levies “don’t need to progress through ICAO, they can just ‘go on and do it’” through bilateral pressure on governments.

SAF scale-up: ACT-SAF, Finvest Hub, lower-carbon fuels

In order to accelerate the SAF scale-up and achieve its 2050 net-zero LTAG, ICAO has already set a voluntary objective to reduce the emissions intensity of fuel in international aviation by 5% by 2030. The CAAF/3 objective covers the use of SAF, lower carbon aviation fuel (LCAF) and other cleaner energies. To support that objective and the SAF scale-up, ICAO in 2022 launched ACT-SAF capacity-building programme and earlier this year the Finvest Hub– an effort to connect SAF and other sustainable aviation projects with investment – whose creation will be consolidated at this year’s Assembly.

ICAO Council’s own working papers address its pre-Assembly implementation plans, for instance through WP/27 which proposes a resolution for the Council, with the technical contribution of CAEP, to undertake a study of real-world fuel accounting, including preliminary book-and-claim, to work out if and how ICAO should support it. Dodd welcomed the move as well-timed, noting that while a global and unified book-and-claim system is desirable, “there’s not enough understanding yet amongst states,” and the priority is to “put in place the right technical details, including some of the book-and-claim and registry solutions being offered by industry like CADO” outside the Assembly setting.

Another of the Council’s paper, WP/25, sketches the Finvest Hub’s functions: matchmaking projects with finance, working with Development Finance Institutions on risk-mitigation, building a funding database, and developing term-sheet templates. Together, ACT-SAF and the Finvest Hub are meant to bridge the technical or financing gaps that may hinder the SAF capacity scale-up, by pairing states that have opportunities with experts and finance.

This cooperative exercise, says Dodd, is the real value of this year’s Assembly. “We will probably be using this Assembly [to make sure] that we are meeting with governments to […] help them understand what the right policies are to put in place to support the energy transition,” Dodd said. “Those sorts of sidelines discussions this time around are likely to be as important as the big discussion in the room.”

The scaling of SAF capacity and finance is a priority on which most relevant working papers are in agreement. Nigeria, Brazil, Ethiopia, Singapore, the EU and Japan reiterate their support for scaling ACT-SAF and operationalising the Finvest Hub, with Brazil – one of ICAO Council’s most active members – additionally proposing the activation of ICAO’s Voluntary Environment Fund for SAF in developing states.

Offering some critiques, China’s submission (WP/112), questions whether the 2030 “5% by SAF/LCAF/cleaner energies” vision and the net-zero 2050 LTAG have been paired with sufficient cost/impact analysis for developing countries, a critique echoed in papers from Pakistan and South Africa.

Disagreements may arise more plainly on the topic of LCAF, a label that covers fossil-based aviation fuel that achieve at least 10% reduction emissions compared to the conventional jet fuel, which can be achieved, for instance, by using renewable electricity during production.  Qatar and Oman, as well as a joint Saudi/Egypt/Nigeria/UAE paper, argue current CORSIA sustainability certification schemes (SCSs) largely exclude lower-carbon fossil-derived fuels – even though they offer near-term abatement and are listed as part of the industry’s path to decarbonise in CAAF/3 – effectively shutting out ready producers, often based in the Global South.

Russia wants to allow national LCAF certification until global schemes expand and to cap sustainability criteria updates to a three-year cadence to reduce policy turnover. On the other side, NGOs and some regulators, notably European countries, see LCAF as counterproductive fossil lock-in that dilutes incentives for advanced SAFs.

Finally, Dodd highlights that although since CAAF/3 he sees “more and more countries starting to put in place policies that will help achieve our goals […] there needs to be commitments from even more countries towards the finance and energy sector to make [them] a reality.” Calls for more involvement from the oil majors are amiss from the working papers, but Dodd notes that although governments must put the right policies in place to de-risk SAF projects, the energy majors also “need to step up”. He finds Shell’s recent decision not to restart construction of its advanced SAF facility in Rotterdam “seriously disappointing, […] given that they’ve got the expertise and the capital and the distribution networks,” while deploring that “they just don’t seem to have the will.”

Beyond fuels: interim target-setting, non-CO2 and more

Interim decarbonisation target-setting is not expected to dominate the upcoming Assembly – either from states’ submissions or from industry predictions – and might even be considered out of step with the stocktaking and implementation mandate given by ICAO’s Secretary General, Juan Carlos Salazar. But it is being pressed by NGOs in their joint paper (WP/384), which argues that ICAO’s climate goal of no net emissions increase above 2020 until net zero in 2050 leaves a vast blind spot which raises credibility questions.

ICSA’s Johnson argues that without interim milestones, the system cannot assess its own efficacy: “If you plot those two points on a graph, what happens in between? Unless [ICAO] identifies a pathway, how can it assess the effectiveness of its tools like CORSIA? How does it know CORSIA is doing enough? How does it know the baseline is set in the right place?”

He acknowledges the political atmosphere of the moment, telling Ishka that “states are obviously reluctant to sign up to something new at this stage, […] we recognise that it’s not going to be at the top of the agenda, but we do think it’s important that it is at least recognised and discussed.” The NGO paper does not ask the Assembly to agree new milestones immediately, but to start the preparatory work so that “in three years’ time we can have a constructive discussion on what those interim targets should be,” Johnson explains.

The NGO paper specifically calls for the Council to propose a CO2 trajectory to 2050, and for concrete milestones to be ready for A43, arguing the topic of non-CO2 also needs stronger acknowledgment to provide a basis for dedicated workstreams, scientific trials and integration into long-term pathways. Johnson also says that although ICAO has done some work already, “NGOs want greater recognition of non-CO2 impacts that go beyond restating the scientific uncertainties.”

By contrast, Dodd suggests that although non-CO2 “will come up”, it is unlikely to dominate, with states’ bandwidth absorbed by CORSIA and SAF scale-up. He stressed that “there is work ICAO is undertaking on the technical level rather than the regulatory level with regards to non-CO2 […] It’s much better that work is done at a technical level right now, so we can actually answer some of the questions we’ve got around mitigating contrail formation before even thinking about regulating operational measures.”

Finally, other proposals that go beyond CORSIA or SAF are less politically charged but show how broad the implementation agenda could stretch. Brazil (WP/440) highlights measurable gains from airspace redesign, citing around 5,000 tonnes of CO2 savings per year across four terminal manoeuvring areas, and asks ICAO to give operational efficiency the same weight as fuels and technology. Venezuela and 15 LACAC states (WP/458) call for ICAO to begin developing climate adaptation guidance, pointing to risks such as sea-level rise at coastal airports, runway flooding and heat-related performance limits.

What to watch for in Montreal

1. CORSIA: Do States agree any steps/timelines to lift the bottleneck for CORSIA-eligible units?

2. SAF scale-up: Movement on LCAF, co-product certification, the SAF Observatory/Outlook concept, an ACT-LTAG programme for technical assistance, a Voluntary Environment Fund and details on the operationalisation of the Finvest Hub.

3. MBMs and GLTSF levies: How hard does the Assembly push back on regional MBMs and levies? It could be an indication for the tone of the discussions with the EU in 2026/2027.

4. LTAG monitoring & non-CO2: Is a work programme for a path to interim targets for 2028’s 43rd Assembly discussed/locked in? Are non-CO2 trials or pilots discussed/proposed/locked in?

After two ICAO Assemblies defined by landmark agreements, ICAO’s 42nd session is being framed as one of consolidation and implementation. The focus on clearing blockages and embedding existing frameworks feels like a natural progression, but one could wonder if a stocktake/implementation Assembly is a luxury the industry can afford in the race to address its climate impacts.

Johnson warns against complacency: “assemblies only happen every three years. So, if you say, ‘well, this is just about stocktaking,’ then the next opportunity to really discuss progress and new things will be in three years’ time. It means very little will have changed in six years. And we’re only 25 years away from net zero.”

Dodd tempers that progress does not hinge solely on the triennial assemblies. ICAO’s environmental work is “continuous”, through ICAO’s governing Council and environmental protection committee, conferences and bilateral dialogues, with the assemblies acting as triennial milestones.  The real test may be whether the 42nd Assembly consolidates in a way that equips ICAO to come back in 2028 with solid proposals for milestones and pathways that carry credibility with regards to its long-term targets.

The Assembly is being streamed on ICAO TV

About the author

Justine El Amrani-Joutey

Justine is an analyst at Ishka SAVi, a sustainable aviation data and intelligence platform covering the intersection between aviation and finance.

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This article is republished with the kind permission of Ishka SAVi