Why Strict Additionality Rules Can Slow Carbon Sequestration Finance

What additionality is supposed to do in carbon markets

Additionality is meant to separate real, incremental carbon sequestration from activity that would have happened anyway. In practice, it is a carbon credit integrity test. It asks a simple but difficult question: would this project still exist without carbon finance?

That question matters to buyers. If a buyer funds a project with business-as-usual economics, the credit may look valid on paper but weak in practice. The risk is not only environmental. It also affects reputation, claims compliance, and auditability. Standards and frameworks increasingly treat additionality as a core quality requirement, not a side issue.

The test also sits close to compliance markets. In CORSIA, ICAO and its Technical Advisory Body keep reviewing eligibility, baseline setting, and methodology design as part of program assessment. That makes additionality part of a broader eligibility and review process, not just a one-time checkbox.

Modern methodologies also go beyond simple financial additionality. They use barrier analysis, investment analysis, and standardized additionality tests. For institutional buyers, that matters because the real question is whether carbon finance is actually needed to make the project happen.

Once that role is clear, the next issue is obvious. What happens when the test becomes so strict that it pushes developers toward projects that are easier to certify, but harder to scale?

How strict tests can push developers toward only marginal sequestration projects

Very strict tests can favor edge-case projects. These are the projects where additionality is easiest to prove because the economics are clearly weak or the barriers are easy to document. That can leave out carbon sequestration projects that are more scalable but also more complex.

The pattern is easy to see across project types. Small biochar projects, soil improvement work, or micro-ARR projects can often clear document-heavy barriers more easily than larger systems with complex supply chains. By contrast, DACCS, BECCS, mineralization, and geologic storage usually need more capital, more infrastructure, and longer offtake horizons.

That creates a distortion. Developers start optimizing for verifiability of the credit instead of total sequestration potential or the marginal abatement cost curve. For corporate buyers, that is a real problem. They often want volume, durability, and long-term supply, not just credits that are easy to validate.

Strict proof requirements also raise development risk. They increase legal and MRV costs, lengthen validation and verification timelines, and make projects more dependent on specialist advisors. The result is a tougher path to market, especially for projects that already need patient capital.

That selection effect becomes even clearer when looking at the largest removal options. Many of them are mature enough, bankable enough, or policy-supported enough that they struggle to fit old-style additionality screens.

Why the most scalable carbon removal options often fail additionality screens

The most scalable removal options often face the hardest additionality questions. Large-scale afforestation and ARR, geologic CCS, BECCS, enhanced weathering, and biomass carbon removal can all be penalized because they may already benefit from public incentives, industrial synergies, or infrastructure logic that complicates a pure project-level test.

The market context shows why this matters. The IEA says CCUS financing has grown more than 15 times since 2020, passing USD 5 billion in 2025. It also says around 90% of announced projects for 2035 have not yet reached FID. That is a strong sign that scale depends on patient capital, not just on static credit rules.

For buyers, the key point is simple. A project can be climate additional in a system sense even if it fails a narrow project-level test. That is why the distinction between project-level additionality and market- or technology-level additionality matters so much.

The standards are already moving in that direction. Verra has updated its biochar methodology to include an investment analysis requirement aligned with the Core Carbon Principles, while ICVCM continues to expand approved methods. That shows a market in transition, not a fixed rulebook.

If the biggest and most useful projects are slowed down or excluded, the next question is who pays for the extra rigidity.

The investment trade-off: integrity gains versus lost capital and slower deployment

Stricter additionality can improve trust. It can reduce over-crediting risk and make buyers more comfortable with claims. But it can also shrink the investable supply of projects and slow deployment.

The financing side matters here. The IEA notes that more than USD 15 billion of commercial debt has been raised over two years, mainly where risk was reduced through policy support and structured offtake. It also stresses that growth depends on long-term contracts, not certification quality alone.

That creates a practical buyer question. Is it better to pay a premium for ultra-tight credits that are scarce, or to build a portfolio with integrity controls, buffer pools, reversals management, and third-party MRV that offers more availability?

For developers, the trade-off is just as sharp. Costly tests raise pre-FID risk, make infrastructure rounds harder to close, and can push capital toward merchant projects that are easier to certify but less climate-optimal.

The market does not need weaker integrity. It needs a framework that protects integrity without freezing finance.

What a more practical additionality framework could look like for global buyers and standards

A better framework would be more flexible, not less rigorous. It would combine dynamic baselines, sectoral benchmarks, periodic reassessment, and technology-specific additionality tests instead of using one rigid filter for every sequestration project.

For buyers, a portfolio approach makes more sense. Early-stage CDR, commercial-scale removal, and infrastructure-enabled sequestration do not carry the same risk profile. They should not be judged by the same investment additionality test, permanence expectation, or leakage profile.

This is also where standards are evolving. ICAO and CORSIA, along with ICVCM, are tightening quality and review requirements. That suggests additionality can become more credible without becoming static.

A practical offtake contract can reflect that. It can require an ex-ante evidence pack, continuous MRV, review at each renewal period, and methodology update clauses. That protects claims while still helping the project scale.

Once the framework becomes more usable, the debate shifts. It is no longer only about one credit. It becomes about how policy, standards, liquidity, and market design shape the next phase of growth.

The policy and market implications for carbon sequestration in the next phase of growth

Too much rigidity creates scarcity, higher prices, and slower deployment. Too much leniency weakens credibility and compresses premium pricing. The market needs a middle path.

The next growth cycle will depend on policy support, long-duration offtake, clear liability rules, and harmonized standards. The IEA is clear that financing becomes possible when risk is de-risked across the value chain, not just at the certification stage.

Global buyers need comparability between standards. They need to compare additionality, permanence, and reassessment rules in a way that supports liquid and verifiable books. Without that, procurement stays fragmented and capital stays cautious.

The most advanced markets are already moving toward high-integrity but investable carbon removal. In that model, additionality still matters. But it is read together with systemic contribution, technology maturity, and bankability.

That is the real lesson. Strict additionality rules can protect carbon credit integrity, but if they are too rigid, they can also slow the finance needed to build carbon sequestration at scale.