Direct air capture is the most engineered form of carbon removal: a plant takes in ordinary air, strips out the carbon dioxide and sends it for permanent storage. The result is a removal credit with very long storage, at a very high price. This page explains how DAC works, how it is credited, what it costs and the risks to weigh. It is part of our guide to carbon credit project types.
How direct air capture works
A DAC plant moves air over materials that bind CO₂, then releases that CO₂ as a concentrated stream. Isometric’s protocol covers projects that chemically or physically capture CO₂ from ambient air using solid sorbents, liquid solvents, membranes or electrochemical processesSource 2. The IPCC describes three basic steps: contacting the air, capturing the CO₂ on a liquid or solid sorbent or a liquid solvent, and regenerating the sorbent or solvent with heat, moisture or pressureSource 1.
The captured CO₂ then has to be stored. The IPCC notes that when CO₂ is captured directly from the atmosphere, carbon capture and storage provides the storage part of the removalSource 5. The storage options Isometric accepts are:
- geological storage in saline aquifers or depleted oil and gas reservoirs, or by mineralising it in rock underground;
- mineralisation reactors above ground, including engineered enhanced weatheringSource 2.
Captured CO₂ can also be used in products instead of stored. That is not the same as a durable removal: the IPCC notes that how long the carbon stays out of the air then depends on the product, from weeks to months for synthetic fuels to centuries or more for building materialsSource 1.
The plant is credited only for the net result. Isometric counts the CO₂ stored, minus what would have happened anyway, minus the emissions from building, running and decommissioning the project, including energy use and leakageSource 2.
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Removal, not avoidance
DAC credits are removal credits. Ecosystem Marketplace lists direct air capture among the technological removals, alongside biochar, that create removals onlySource 7. Each credit stands for CO₂ that was already in the atmosphere and has been taken out.
The IPCC concludes that carbon dioxide removal is unavoidable to counterbalance hard-to-abate residual emissions if net zero is to be reachedSource 5. The Oxford Offsetting Principles point to DAC with geological storage as a removal with a low risk of reversalSource 6. For the broader comparison, read removal vs avoidance credits.
How permanent is it?
Geological storage is the main reason buyers pay for DAC.
- Isometric requires CO₂ to be stored through physical or chemical trapping for more than 1,000 yearsSource 2.
- Puro.earth’s Geologically Stored Carbon methodology, which covers both DACCS and bioenergy with carbon capture and storage, requires storage for at least 1,000 yearsSource 3.
- The IPCC estimates storage time scales of 10,000 years or more for methods that store carbon in geological formations, against decades to centuries for vegetation and soilsSource 5.
Low risk is not zero risk
The Oxford Principles note that some leakage from geological reservoirs could still occur, for example through earth movements or unexpected gas movement between rock formations, so monitoring and a plan to compensate any reversal are still neededSource 6.
What does DAC cost?
There is no openly published average transaction price for DAC credits, which is why our price snapshot leaves it out. The best open benchmark is a cost estimate: the IPCC puts the cost of DACCS at $100–300 per tonne of CO₂, at the high end of the removal methods it assessedSource 5.
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| Item | Value (USD per tonne) |
|---|---|
| DACCS cost estimate (IPCC) | 100–300 |
| Biochar, average price 2024 | Over 160 |
| All removal credits, average price 2024 | 19.50 |
As of Oct 2026
The cost estimate comes from the IPCCSource 5 and the prices from Ecosystem MarketplaceSource 7. The Oxford Principles say removals with geological storage remain challenging to invest in because of novel technology, limited supply and, for now, high costsSource 6. See carbon credit prices for the current snapshot.
Risks and integrity issues
- Energy and life-cycle emissions. A plant powered by fossil energy can emit a large share of what it captures. Protocols subtract energy, embodied and process emissions before issuing creditsSource 2, so check the net figure, not the gross capture.
- Scale and supply. The Oxford Principles call for a thousand-fold increase in carbon removal with a low risk of reversal by 2050, and note that supply of high-quality removals is still very limitedSource 6.
- Storage after issuance. Under Isometric’s protocol, reversals that happen after credits are issued are handled outside the main calculation, through monitoring and a reversal risk assessment at each crediting period renewalSource 2.
- Forward sales. Because capacity is scarce, some DAC tonnes are sold before they are delivered. A credit that has not yet been issued and retired is a promise, not a removal.
Gross capture is not net removal
If a seller quotes tonnes captured, ask how many credits were issued after subtracting energy and other emissions, and which registry shows them.
Standards and methodologies
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| Programme | Methodology | ICVCM status |
|---|---|---|
 Isometric | Direct Air Capture, v1.1 | CCP-approved (October 2025) |
 Puro.earth | Geologically Stored Carbon (covers DACCS and BECCS) | Not covered by this decision |
Logos identify the organisations named; no endorsement is implied.As of Oct 2026
The ICVCM’s October 2025 decision approved six carbon removal methodologies, including Isometric’s DAC protocol, and approved a Gold Standard concrete carbonation methodology on condition that its CO₂ comes from direct air capture or biogenic sourcesSource 4. Puro.earth’s methodology details come from its own pageSource 3.
Buying DAC credits
- Decide the role. Most buyers use DAC as a small, durable slice of a wider mix. The portfolio approach explains how.
- Check delivery. Know whether you are buying issued credits or a future delivery.
- Verify retirement in the registry; see how to verify carbon credits.
Compare with biochar and enhanced weathering, the other engineered removals.