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CORSIA aviation carbon market guide

CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) is one of the most important aviation carbon market systems for airlines, offset buyers, carbon project developers and voluntary carbon market watchers. Use this page as the CORSIA route map: if you are new to the topic, begin with CORSIA explained, then move into eligible emissions units and the CORSIA vs EU ETS (European Union Emissions Trading System) comparison. If you already understand the basics, the price guide and voluntary carbon market guide explain demand, supply and eligibility risk.

What is CORSIA?

The scheme is the International Civil Aviation Organization's global system for addressing emissions growth from international flights. In simple terms, participating airlines may need to monitor emissions from covered routes and cancel eligible emissions units to offset growth above the scheme's baseline.

The detail matters because CORSIA does not treat every carbon credit as acceptable. Airlines need eligible units from approved programmes, with rules on vintage, activity type, host-country authorisation, double counting and corresponding adjustments. That makes CORSIA a useful lens for understanding credit quality, policy risk and demand in the wider voluntary carbon market.

CORSIA guides to read first

Read next	Best for	Why it matters
CORSIA explained: aviation offsetting and Phase 2	First-time readers	Understand what the scheme is, who it applies to, why Phase 1 creates credit demand and what Phase 2 changes from 2027.
CORSIA eligible carbon credits	Airline buyers, brokers and project developers	Learn what makes a credit eligible, why programme approval matters and which risks to check before relying on a unit.
CORSIA vs EU ETS	Policy and compliance readers	Compare the global offsetting system with Europe's cap-and-trade system for aviation emissions.
CORSIA Phase 1	Readers tracking 2024 to 2026 rules	See why Phase 1 matters for demand, airline participation and eligible credit supply.
CORSIA and the voluntary carbon market	Carbon market participants	Understand how airline compliance demand can influence quality expectations and market segmentation.
CORSIA credit prices	Buyers and market analysts	Assess the factors that can affect pricing, including eligibility, supply, demand, vintage and policy confidence.
CORSIA eligible programmes	Project developers and procurement teams	Track which standards and programmes are relevant when assessing whether units may qualify.

Why CORSIA matters

CORSIA sits at the intersection of aviation policy, carbon credit integrity and Article 6 accounting. The rules are technical, but they matter commercially because eligibility affects which units airlines can use, how buyers assess supply, and how project developers think about demand.

It also matters because CORSIA creates a clearer distinction between ordinary voluntary carbon credits and units that can be used for a specific aviation compliance purpose. That distinction can affect price, buyer confidence, project eligibility, programme approval and the way brokers describe supply. A credit that looks attractive in the voluntary market may still be unsuitable for an airline if it does not meet the relevant CORSIA requirements.

How to read the CORSIA guides

If you are...	Focus on	Useful check
An airline or buyer	Eligible emissions units, vintages, authorisation and retirement evidence.	Do not assume a registry-issued credit is automatically CORSIA eligible.
A project developer	Programme approval, methodology, host-country status and demand signals.	Eligibility can affect buyer pool and pricing, but rules can change.
A market analyst	Supply, demand, compliance periods, airline participation and price segmentation.	CORSIA demand should be compared with wider voluntary market demand.
A sustainability reader	How aviation offsetting differs from direct emissions reductions.	Offsetting does not replace fuel efficiency, fleet changes or sustainable aviation fuel.

Key questions to understand

Which flights and airlines are covered by CORSIA?
Which emissions units are eligible, and for which compliance periods?
How does CORSIA avoid double counting?
How does it differ from the EU ETS (European Union Emissions Trading System) and UK ETS (UK Emissions Trading Scheme)?
What happens when voluntary market credits are not CORSIA eligible?
How might airline demand affect credit prices and supply?
What should a buyer check before relying on a CORSIA-related claim?

Bottom line

CORSIA is not just an aviation compliance scheme. It is also a quality filter for parts of the carbon market. Understanding which credits qualify, how the rules compare with emissions trading systems, and how demand may evolve helps buyers, project developers and analysts make better decisions.