Will CORSIA flight offsetting scheme pay for green projects - or greenwash?

Reuters

27-05-2025

May 16 - Airlines using offsets to market flights as sustainable have frequently been accused of greenwash, opens new tab by campaigners, with the risks demonstrated last year by the legal precedent-setting Dutch Court ruling against KLM.
Now, however, the industry is gearing up to buy hundreds of millions of credits through a global scheme agreed under the United Nation's International Civil Aviation Organization (ICAO).
The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) is expected to unlock unprecedented demand for carbon offsets. But will the scheme have enough integrity baked in to assuage greenwash concerns?
CORSIA aims to offset growth in the sector's greenhouse gas emissions by mandating airlines to purchase credits for each tonne they emit over a baseline of 85% of 2019 emissions.
As with most offset schemes, airlines are only meant to buy carbon credits as a last resort, once they have put in place other emissions reduction strategies. These include making aircraft and engines more efficient and lighter, more efficient operations such as take-off and landing, and electric engines for short-haul flights.
CORSIA also has a list of eligible feedstocks for sustainable aviation fuels (SAFs), which airlines can use to reduce their need to purchase offsets, though these are in short supply.
CORSIA is being implemented in phases ahead of becoming mandatory for all international flights from 2027. During a pilot phase, from 2021-2023, and the first phase, 2024-2026, offsetting is required only for flights between states that volunteer to participate, but as of this year, 129 states are included in the scheme.
Integrity under scrutiny
IATA insists that CORSIA and the carbon credits sold under it are high integrity, backed by several safeguards and independent checks. In December, the body approved four new CORSIA-compliant carbon standards: Gold Standard, Verra, Climate Action Reserve and Global Carbon Council, adding to the two existing standards, American Carbon Registry (ACR) and Architecture for REDD+ Transactions (ART), which manages The REDD+ Environmental Excellence Standard (TREES).
All projects must meet eligibility criteria that emissions reductions are real, additional and permanent.
IATA has, however, removed some categories of credits that have attracted the most controversy from eligibility for CORSIA. These include afforestation and reforestation, and project-level REDD+ schemes, which pay for projects that protect forests that are under threat.
Allowed are jurisdictional-level REDD+, which are administered at a national level, the type of scheme certified by ART TREES.
In addition to ICAO's process, governments of host countries must agree 'a corresponding adjustment' to prevent double counting, so that credits supporting projects under CORSIA are not also used to meet national obligations under the Paris Agreement on climate change.
So far, only Guyana has agreed a corresponding adjustment for 7.15 million credits issued by TREES.
One million of these were purchased for a fixed price of $21.70 by 11 airlines late last year, when IATA held the first large-scale auction. But the forestry schemes the South American nation intends to finance through CORSIA have previously been criticised by scientists, who said they would overstate the amount of emissions they will prevent, given that Guyana is a country with high forest cover, but low amounts of deforestation (HFLD).
While some Indigenous groups has supported the Guyanese government, others have complained to ART about insufficient consultation, and questioned whether they are receiving adequate compensation for their role in protecting Guyana's forests.
ART, however, defends its crediting approach for HFLD countries like Guyana, citing gold mining exploration as one of numerous threats to Guyana's intact forests. "Forests cannot be protected indefinitely without ongoing support and incentives."
It also said all 242 Indigenous communities in Guyana have received funds from an earlier sale of 33.47 million TREES credits, some of which had been bought by corporate buyers.
While Guyana's credits are currently the only game in town under CORSIA, 15 countries – mostly in Africa – are in the process of issuing Letters of Adjustment, according to IETA. 'These are like a promissory note that you will issue a corresponding adjustment within two years,' explains Will Gifford, policy manager, aviation and natural climate solutions lead at IETA.
'A lot of countries are figuring out how many credits they can authorise to go out of the Paris Agreement bucket and into the CORSIA bucket. Guyana is the only one we have now, but we expect a lot more,' he says.
Until some of these come to fruition, just 7.6 million credits meet the eligibility criteria for CORSIA, according to carbon market analysts Abatable. It estimates demand from airlines at 135-182 million units during the first phase, leaving demand two or three times larger than supply. This gap widens during the second phase, when it forecasts demand as reaching 825 million to 1.6 billion units, nine to 10 times supply.
In spite of the removal of some project types from CORSIA, critics have questioned the emissions-reduction potential of some categories that are still eligible, such as projects that provide communities with efficient cookstoves to replace burning of wood cut from local forests.
In March, the Integrity Council for the Voluntary Carbon Market (ICVCM) tightened up the eligibility criteria for cookstove projects that meet its Core Carbon Principles on the voluntary carbon market, removing those at risk of overestimating the amount of carbon they reduced due to insufficiently robust methodology.
Derik Broekhoff, a senior scientist at the Stockholm Environment Institute, says such credits are, however, still eligible under CORSIA.
'The approach under CORSIA has been to assess the major credit issuing programmes and approve them, with some restrictions on particular categories of projects. But one of the challenges with these markets in general is that, even within individual categories, you find good and bad projects, and there's no granular-level screening to weed out the bad ones,' he says.
Bastien Bonnet-Cantalloube, expert on decarbonisation of aviation and shipping at Carbon Market Watch, said: 'It's fairly positive that the eligibility rules have been made more stringent for phase one (of CORSIA). But we've already seen problems with the very first batch, so we don't expect these other registries and the new batch of credits that will be made available to airlines to be great.'
Gifford of IETA believes that international scrutiny of offsets under CORSIA will bring accountability to the system. Integrity will also be supported by the fact that countries hosting the projects funded by the scheme must also approve them, he believes.
'We can draw a distinction here between CORSIA and a voluntary scheme for passengers to offset emissions from their flight. Even though CORSIA is a global scheme, there is local control over how it is used. It's not simply anyone buying whatever they want from wherever they want,' he says.
The LEAF Coalition is a public-private coalition that has signed agreements with countries including Ecuador, Costa Rica and Ghana to undertake jurisdicational scale REDD+ reforestation projects.
Its credits have been certified by both ART TREES and the ICVCM. Some will be sold to airlines through CORSIA, once the countries have signed corresponding adjustments.
Eron Bloomgarden is CEO of Emergent, which acts as a non-profit intermediary for the coalition. He says reversing deforestation is reliant on sufficient finance for projects that make protecting forests worth more than destroying them.
'The constraint is really unlocking large sources of demand – this is where CORSIA comes in. Our goal is to achieve net zero deforestation by 2030. To do that, we need to catalyse $10 billion-$20 billion by 2030, and CORSIA could provide maybe a quarter of that,' he says.
Bloomgarden says the scheme should be viewed as a transition tool, until efficiency technologies and alternatives to long-haul travel become viable. 'Airline offsets are the best possible solution in the intervening time – they're as good as, if not better, than SAFs (sustainable aviation fuels),' he says.
Judit Legrady, senior managing consultant for Article 6 and CORSIA at consultancy South Pole, points out that growth in demand for international air travel is estimated at 4-5% a year.
'If you look at projected annual improvements in efficiencies of aircraft fuel or operations, and those resulting from using SAF, there will still be a CO2 emissions-reduction gap,' she says
Alongside addressing residual emissions through offsets, CORSIA will incentivise airlines to reduce emissions, invest in new technologies and adopt SAF.
Juan Carlos Arredondo Brun, director of knowledge, policy and advocacy at Abatable, points to the additional environmental and social benefits of projects funded by CORSIA, such as reductions in air pollution and support for livelihoods of communities where projects take place.
It will also provide a continuous source of funding for up to 30 years' operation, which will be an improvement on the ad hoc funding such projects typically currently receive through voluntary markets.
'CORSIA is the first truly global carbon market, so it should be allowed to become more mature and efficient. We must not lose sight of the benefits of projects funded by CORSIA that go beyond the quantification of carbon emissions reductions,' he says.
For Bloomgarden, CORSIA marks a shift in the global approach to greenhouse gas emissions. 'Given where we are in the climate emergency, every tonne of emissions should be paid for,' Bloomgarden adds. 'The era of using the atmosphere as a free resource to store our climate pollution should be over.'
Terry Slavin contributed to this article.
This feature is part of The Ethical Corporation's in-depth briefing on Sustainable Tourism. To download the PDF, click here