Airport Carbon Credits: Purchases, Risks and Choices

At a Glance · Airport Carbon Credits

Airport Carbon Accreditation is voluntary, yet the 85 airports at Levels 3+ and 4+ that retired 495,665 tCO2e of offsets in the programme’s sixteenth reporting year, and the 21 airports at Level 5 that retired 20,754 tCO2e of removals, did so to support public claims of neutrality and net zero, and those claims are now read against consumer law and credit-integrity decisions that the accreditation itself does not settle.

The offset records airports have published show purchases weighted towards cookstove, landfill gas and grid-connected renewable energy credits, bought once a year through a broker against a retirement certificate, with two records retiring credits six to ten years after the reduction took place, so that the ICVCM’s rejection of the main renewable energy and four cookstove methodologies, the EU ban on offset-based neutrality claims and the shortage of removals all reach the airport without having been priced into the purchase.

Airports should buy to their level and to the direction they are moving in, Level 3+ buying only what its final renewal requires from ICVCM-approved methodologies within a three-year vintage, Level 4+ adding a removal share that rises each year and Level 5 contracting a diversified removal portfolio years ahead, with every purchase backed by a due-diligence file and every claim worded to the accreditation level rather than to neutrality.

Airport Carbon Accreditation, launched by ACI EUROPE in 2009, certifies airports at seven levels, from mapping a carbon footprint at Level 1 to net zero at Level 5, and at Levels 3+, 4+ and 5 it requires the airport to retire carbon credits against its residual emissions, which 85 airports at Levels 3+ and 4+ and 21 at Level 5 did in the programme’s sixteenth reporting year, from May 2024 to May 2025.¹ The programme’s verifiers check that each credit comes from an eligible programme, sits within the vintage window and has been retired, whereas consumer law judges the claims an airport makes to passengers on their own merits, whatever certificate stands behind them.²

The EU Directive on Empowering Consumers for the Green Transition has applied since 27 September 2026 and bans, in all circumstances, claims that a product or service has a neutral, reduced or positive greenhouse gas impact on the basis of offsetting, with no transition period for claims already in use, as we set out in our analysis of the EU offset claims ban. The UK Digital Markets, Competition and Consumers Act has allowed the Competition and Markets Authority to fine for unfair commercial practices directly since 6 April 2025, up to 10% of global turnover, and the Australian Competition and Consumer Commission’s guidance of December 2023 expects a business to state which emissions a claim covers and how far it relies on purchased offsets.^6,7,8

Aviation claims have already been tested, the District Court of Amsterdam having found in March 2024 that 15 of 19 statements challenged in an airline’s sustainability campaign were misleading, and a complaint to New Zealand’s Advertising Standards Authority against an airport’s climate positive claim, which argued that the claim rested on offsets and left out flight emissions, having ended in February 2024 after the airport said it had stopped using the phrase.^9,10 An airport’s exposure therefore turns on two things the accreditation does not settle, the quality of the credits behind its claim and the words in which the claim is made.

Issue 2 of the Carbon Offset Requirements, which applies to credits bought since June 2025, obliges each airport to publish the crediting programme, project, volume and retirement date of the credits it retires, and the programme totals, read with the records that eight airports and airport groups have published, give a direct view of the credits behind accreditation.^1,2,11 At programme level, offsetting is concentrated at Level 4+, where 53 airports retired 391,989 tCO2e in Year 16 against 103,676 tCO2e from the 32 airports at Level 3+, the combined 495,665 tCO2e being 26% below the 667,016 tCO2e retired in 2023 to 2024, while Level 5 removals rose to 20,754 tCO2e from 17,465 tCO2e.¹

Credits retired under Airport Carbon Accreditation, Year 16, tCO2e

Level 4+ offsets

391,989 t

53 airports

Level 3+ offsets

103,676 t

32 airports

Level 5 removals

20,754 t

21 airports; 17,802 t from the Verified Carbon Standard

Offsets at Levels 3+ and 4+ together fell to 495,665 t from 667,016 t in 2023 to 2024; Level 5 removals rose from 17,465 t.

The offsets retired at Levels 3+ and 4+ are reported by programme but not by project type, host country or vintage, so that the airports’ own records are the only public view of what was bought, and they show avoidance credits accounting for most of the tonnes named, from landfill gas, cookstoves and grid-connected wind, hydro and solar, with the projects located in China, Brazil, Burkina Faso, Cambodia, Peru, Mali, Turkey and India.¹¹

Table 1 · What published airport offset records and registry retirement notes show, with airport names withheld. Sources: retirement certificates, offsetting reports and disclosure pages of eight airports and airport groups, read November 2026; Climate Decode registry data, Verra retirements to 2 June 2026; Airport Carbon Accreditation Annual Report 2024-2025.

Registry records add a view from India, where each retirement note names the airport and the accreditation level it supports, and Climate Decode’s registry data to 2 June 2026 shows Indian airports retiring 134,829 tCO2e of 2020 to 2022 vintage credits from grid-connected solar and wind projects in India under ACM0002 between December 2023 and September 2024, mostly for Level 4+, before Issue 2 excluded that methodology, while three Indian airports retired 20,147 tCO2e of 2020 and 2021 vintage removals from two afforestation projects in China for their Level 5 claims between June 2024 and December 2025, so that the first Level 5 removals in Asia rest on a narrow and ageing base of plantation credits from outside the country while Indian reforestation and soil carbon projects issue on the same registry.¹⁶ The line between avoidance and removal is not always kept in these notes either, two retirements of REDD+ credits under VM0015 in 2025 and 2026 being described as removal credits or as part of Level 5, although REDD+ credits avoid emissions rather than remove them and Level 5 accepts removals only.^2,16

The published records cover the airports whose disclosures could be read in full, most of them in Europe, and the registry notes add India, so that together they indicate the pattern of purchasing rather than market shares, and the direction the Danish hub has taken is the one set by Level 5 and by the Oxford Offsetting Principles, revised in February 2024 to shift residual-emission offsetting towards removals with long-lived storage by the net-zero date.¹²

The free report lists every published airport record by credit type, host country, standard, vintage and volume.

Purchasing in these records follows an annual cycle in which the airport closes its footprint, calculates the residual volume, buys credits shortly before the accreditation application, retires them and publishes the certificate, with the purchase commonly placed through a broker or an offset retailer, so that the airport sees a price and a certificate rather than the project behind them.¹¹ The purchase and retirement recur every year, including the interim years in which no verification takes place, while the Verifier Requirements of May 2026 set verification every second year at Level 3+, every third year at Levels 4 and 4+ and every year at Level 5, so that at Level 4+ a credit that fails the rules can be retired in two successive interim years before a verifier examines it.^2,4

Table 2 · The annual purchasing cycle and the gap each stage leaves under the current rules. Sources: published airport records; Carbon Offset Requirements, Issue 2; Directive (EU) 2024/825.

The cycle tends to select the lowest-cost credit that passes eligibility, since each purchase is made against a deadline and judged on its certificate, and eligibility under Issue 2 does not by itself test over-crediting, which is where the largest losses of value in recent years have arisen, in cookstove and forest projects whose credits registries have since cancelled or found to have been issued in excess.^13,14

The exposures that follow from this cycle fall into six groups, each of which already has a public record, and Table 3 sets out that record against what it means for an airport at Levels 3+, 4+ or 5.

Table 3 · Risks a voluntary offsetting claim exposes an airport to. Sources: notes 3, 5 to 10 and 13 to 15.

Two of these exposures are new in 2026 and fall on every airport that offsets, the EU ban on offset-based neutrality claims and the phasing out of Level 3+, under which an airport whose Level 3+ certificate expires by 31 December 2026 may renew only once more, so that a Level 3+ airport needs a decision on Level 4+, and on the credits that Level 4+ will require, before that renewal runs out.^3,6

The choice of credit follows from the airport’s level and the direction it is moving in, and Table 4 sets out, for each level that retires credits, what to buy and how to contract and claim, consistent with Issue 2, the ICVCM decisions and the Oxford Offsetting Principles.^2,5,12

Table 4 · What each accreditation level should buy. The free report adds what to avoid at each level, a six-question self-check and an illustrative due-diligence card. Sources: Carbon Offset Requirements, Issue 2; Levels 3 and 3+ Requirements, Edition 1.0; ICVCM decisions; Oxford Offsetting Principles (2024).

At every level the due-diligence file should record, for each project, the methodology and its ICVCM status, the baseline and over-crediting risk, permanence and buffer arrangements, safeguards and co-benefits, and the vintage and retirement record, so that the same file serves the verifier, the airport’s disclosure and any later challenge to its claim, and we set out the detailed rules in our guides to Level 3+ credit procurement and to Level 5 removal requirements.

Climate Decode Platform

Canopy runs the airport’s credit portfolio from accreditation level to retirement, and Market Watch tracks the credits it draws on.

Climate Decode · Free Credit and Claims Check

Know where your airport’s credits and claims stand

Send the last retirement certificate and the claim wording in use to [email protected], and we return a one-page check against Issue 2, the ICVCM decisions and the consumer rules in your markets within five working days, free of charge.

Notes

Sources

This article summarises public documents and published airport records for information and is not legal advice; the Airport Carbon Accreditation documents and the programme Administrator remain the authority on accreditation requirements, and Climate Decode is not affiliated with ACI EUROPE or Airport Carbon Accreditation.