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Another resounding failure for ICAO

byJames Higham
28 October 2025
9 minute read

Earlier this month the International Civil Aviation Organisation concluded its 42nd General Assembly in Montreal. The result has been another dismal failure for action on international aviation emissions and a failure for sustainable tourism. It raises the question: at what point do you accept that ICAO is incapable of dealing with aviation emissions?

Transcript

The 42nd ICAO General Assembly took place recently, from 23 Sept – 3 October, at the ICAO headquarters in Montreal, Canada. The Assembly takes place every three years. Given that frequency, and the fact that the IPCC’s 2030 climate targets loom in just four more years, you would think that the UN would consider the 2025 ICAO Assembly a rather urgent priority. So what reassurance of focus and effort has ICAO offered us after their recent Assembly? 

The best person to comment on this is Chris Lyle who has had a long career in air transport. He has been actively involved in aviation’s climate change impacts since 1997, when the Kyoto Protocol was negotiated and agreed. Nearly 30 years ago. It was at Kyoto that of the UN Framework Convention on Climate Change (UNFCCC) referred the problem of reducing greenhouse gas emissions from international aviation to the International Civil Aviation Organisation (ICAO).

After the recent ICAO Assembly Chris shared his reflections in a report on LinkedIn. In his report he summarises the outcomes of the ICAO Assembly and considers what progress it made. In his words: “The 42nd Session of the ICAO Assembly has come and gone with net-zero progress on aviation emissions mitigation policy, just 26 pages of Resolution blah blah blah”. In his view, the ICAO’s 2025 Assembly made “no significant advance from its last Assembly, three years ago”.


In his report he summarised the failure of the ICAO Assembly in these terms:

  1. Still no intermediate targets towards the “aspirational goal” of net-zero carbon emissions by 2050
  2. Adoption of a 2023 Sustainable Aviation Fuels recommendation “to achieve a collective global aspirational Vision to reduce CO2 emissions in international aviation by 5%”, but retention of the phrase “compared to zero cleaner energy use”. This is very different from an absolute reduction in emissions. It ensures that the vast majority of unabated emissions will continue to grow as the aviation sector itself grow.
  3. No strengthening of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). Thus, CORSIA will continue to apply only to emissions above 85% of 2019 levels with the vast majority of international aviation emissions unaccounted;
  4. The inherent problems of the concept of offsetting remain unaddressed;
  5. No action on non-CO2 aviation emissions other than “exploring means to quantify potential climate impacts …..and measures to address such impacts”
  6. No consideration given to contrails which we know is a further driver of aviation emissions.

CORSIA has been ICAO’s post-Paris response to the problem of aviation emissions since it was announced after the 39th Assembly in October 2016. We wrote about its failure in a paper published in 2019 (Higham, Ellis and Maclaurin, 2019). Chris Lyle has been very clear about CORSIA’s multiple flaws. CORSIA only applies to emissions growth above 85% of 2019 levels. By way of illustration, in the European context this only addresses 26% of the EU’s international aviation CO2 emissions by 2035. The hopes pinned on carbon offsets means no commitment to stablise or reduce emissions at source – in other words a free rein to continue to increase gross emissions as the industry continues to grow.

The environmental integrity of CORSIA’s eligible carbon credits also remain in grave doubt. An analysis of the carbon credits issued by mid-2025 found that in some cases 84% of credits did not represent any real emissions reductions. European aviation is projected to spend somewhere in the range of €7 billion to perhaps as much as €43 billion on offsets over the next decade – which the carbon offset intermediaries will be very pleased about.

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The problem, as we all know, is that aviation is notoriously difficult to decarbonize. Recent studies have again confirmed the high tourism emissions attributed to aviation (Sun et al., 2024) and the fact that marginal technical improvements under current technologies continue to be totally overwhelmed by contributed growth in air travel volume.

Since 1997 the International Civil Aviation Organization (ICAO) has been the global body charged with the responsibility of managing aviation emissions. Following CORSIA, ICAO’s Long-Term Aspirational Goal (LTAG) for net-zero emissions by 2050 continues to centre on market mechanisms and sustainable aviation fuels (Lyle, 2025). ICAO flatly refuses to consider demand management which, in the absence of new low emissions aviation technologies, is the only effective way to stabilise and reduce high international aviation emissions.

Sustainable Aviation Fuels (SAF) and alternative propulsion sources such as electricity and hydrogen have been promised as works in progress and causes for optimism. Currently much hope is placed on SAFs which may reduce lifecycle GHG emissions compared to standard jet fuel when blended with convention jet kerosene. Crucially, for the aviation industry, SAFs do not require new aircraft designs or engines modifications, unlike other propulsion technologies such as battery electric or hydrogen.

But the current volume of SAFs is very low – approximately 0.7% of kerosene worldwide – and the cost of SAF ranges from 2.5 to 6-7 times the cost of kerosene. Chris Lyle also outlines the serious concerns about SAFs full lifecycle impacts: SAFs still generate GHGs when combusted; they impact on direct and indirect land-use changes; they require high renewable energy inputs to produce and the potential available volume of supply is limited – so there are enormous opportunity costs involved when most would agree the greater priority is to actually transition economies and societies to renewable energy. Chris Lyle also points out the considerable barriers in necessary investment, pricing, and scaling up to commercial level.

The same sorts of issues apply to synthetic e-fuels which are considered part of the SAF suite of potential solutions. But e-fuel production requires “green” hydrogen, which needs a considerable volume of renewable energy to produce, and supply for aviation is constrained by strong demand for e-fuels in other sectors of the economy.

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But really the fundamental problem is that ICAO’s principal focus is on growing the global economy and expanding access to flying. With this single-minded focus it is necessary to wilfully ignore the fact the a tiny minority of the world’s population flies regularly, while the costs of climate change particularly impact the most vulnerable who are generally excluded from flying (Young et al., 2014).

The reality is that ICAO is a member organisation and its members are represented by governments that seek to protect national sovereignty and serve national economic and industry interests. Naturally, individual member states give priority to protecting their own economic interests, to advance economic growth through aviation and tourism, as do all other member states. It has been repeatedly stated, since Kyoto 1997 and particularly since Paris 2015, that because of these interests ICAO is totally incapable of putting in place policy mechanisms that will be effective in reducing aviation emissions.

In the absence of strong climate policies aviation emissions will at least double the 2019 benchmark by 2050. As other sectors actively decarbonise, it is estimated that aviation emissions may grow from 2.5% of total global emissions to 20%. If so, at some point along this unwanted pathway the failure of ICAO will be recognised and decisive action will then need to be taken.

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So what next? In sustainable tourism, aviation emissions are the “elephant in the sky”. Most of our tourism emissions – upward of 60% – come from travel to and from the destination, which usually involves flying. Long haul aviation is particularly problematic. One return long haul flight puts someone beyond their annual personal emissions quota if we are to collectively meet our 2015 Paris Climate targets. A flight from Europe to New Zealand accounts for over 95% of the total emissions arising from such a trip. Needless to say, New Zealand is extremely vulnerable to the risk of flight shame if the emissions question remains unresolved.

So responsible tourists need to think carefully about their choice of destination and specifically account for air travel emissions in their decision making. That is not to say forego long-haul flights altogether, but seek closer destinations and seek low-carbon alternatives, including virtual experiences, where possible. And needless to say, New Zealand is extremely vulnerable to the risk of flight shame if this equation is not resolved.

Carbon offsetting has been presented as a form of compensation but we know that carbon offsetting is fatally flawed. Most carbon offset programmes achieve little or nothing and can in fact be more damaging than not. The majority of offset programmes do not deliver what they promise and are worse than a waste of money. Some airlines also now allow passengers to purchase SAFs to cover a small fraction of their emissions, or to pay for Carbon Capture and Storage (CCS). These mechanisms can be criticised on various grounds. Some have argued that they amount to a ruse by airlines to transfer the guilt, accountability and costs of emissions from the airlines themselves to their customers (Young et al., 2014), and that they therefore absolve the responsibility of airlines who can then reduce or delay action to reduce emissions at source.

Speaking of which, Chris Lyle also calls for consumers to be very wary about the claims made by airlines who are far from immune when it comes to misinformation. Airlines often make grand claims about efficiency gains as measured in carbon intensity. This describes an increase in efficiency per passenger kilometre, but this is very different to reducing carbon emissions. While efficiency gains are good, they have been historically overwhelmed by continued growth. Airlines will not sign up to reducing gross emissions because they do not believe it is achievable under existing technologies and to reduce absolute emissions would, under the current technical regime, require a reduction in demand.

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Travellers also need to be wary of the claims made by airports. Some airports have made grand claims about being carbon neutral, but airports exclude emissions from flights, which they allocate to the airlines themselves, even though those emissions are critical to their business. Airports typically only account for their own ground-based emissions which is very misleading.

Furthermore, Susanne Becken reports on the scale of significant new airport projects and airport expansion projects, that are currently underway, highlighting the enormous disconnect between growth in air travel and climate goals. She reports that investments in new airports currently total over US$600 billion globally – mostly government funded. She explains that this coincidentally the scale of investment required to advance new aviation technologies and alternative fuels. Of course the true costs of new airport projects lie in the creation of transport path dependencies that lock travellers into the current air transport regime for decades to come. Not to mention the wider infrastructure requirements needed to support expanding airports. 

As an example, Gatwick airport’s £2.2bn second runway plan has recently been given the go-ahead by the UK’s transport secretary, Heidi Alexander (The Guardian, 2025). The aim of the new runway is to increase Gatwick’s capacity by an additional 100,000 flights a year. A government spokesperson said that “With capacity constraints holding back business, trade and tourism, this is a no-brainer for growth”. Once again governments giving priority to growth without concern for climate commitments or future emissions. Or the further strain that this scale of growth will place on the surface transport infrastructure of London and surrounding counties to the south, including the massively strained M25.

Chris Lyle concludes that ultimately it is up to us – the people who create demand for air travel – who need to take action. Our individual responses should not only include reviewing our own air travel decisions. We should also be keeping well informed, supporting environmental groups and, most importantly, we should be lobbying government representatives to urge them to take regulatory action, and vote accordingly. Governments will ultimately have to take their own direct action, individually or through coalitions of willing nations (Higham, Ellis and Maclaurin, 2019).

Conclusion

Chris Lyle’s report makes very sobering reading. He states that “The time has come to leave ICAO to its own devices…”. In the three decades since the Kyoto Agreement ICAO has consistently failed to advance meaningful collective action to address aviation emissions. Time and again it has proved itself totally incapable of advancing the policy mechanisms required.

In 1997 the UN Framework Convention on Climate Change (UNFCCC) referred the problem of reducing greenhouse gas emissions from international aviation to the International Civil Aviation Organisation. After repeated failures, it is now time for the UN to withdraw this referral and find or form an organisation that is actually capable of fulfilling this important task.

References

Author
James Higham
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