Permanence, Buffer Pools and Reversal Risk: Why You Don't Get Paid for Every Tonne
Soil carbon and trees can release their carbon again. Registries manage that with buffer pools that withhold a share of every project's credits. Here's what permanence means for Indian farmers, FPOs and the tonnes you actually get paid for.
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There is a number every farmer is quoted and a smaller number they are actually paid for. Part of that gap is commission, part is cost recovery — and part is a mechanism most enrolment conversations skip entirely: the buffer pool. Understanding it is essential to understanding why verified tonnes and saleable credits are not the same thing.
Quick answer
Why don't you get paid for every verified tonne?
Because land-based carbon can be released again. Soil carbon returns to the atmosphere if fields are ploughed; tree carbon is lost if trees are felled or burn. To manage this, registries assess each project's reversal risk and withhold a percentage of every credit batch into a shared buffer pool that covers losses across the programme. Those withheld credits are not issued to the project and generate no revenue. A project quoting gross tonnes without mentioning the buffer is overstating what you will be paid.
Why permanence is a real problem, not a technicality
A tonne of CO2 kept out of the atmosphere for two years is not worth the same as a tonne kept out for a century. Buyers are purchasing a durable climate outcome, and the credibility of the entire market rests on that durability being real.
Some carbon pathways are inherently durable — geological storage, for instance. Agricultural carbon is not. It is stored in living systems and in soil that remains under active management, and it can be undone by an ordinary farming decision.
| Pathway | Where the carbon sits | Main reversal risk |
|---|---|---|
| Soil organic carbon | Soil organic matter, actively farmed | Return to tillage; residue removal or burning |
| Agroforestry | Standing tree biomass | Felling, fire, drought, pest, poor survival |
| Biochar | Decomposition-resistant carbon in soil | Comparatively low — durable by nature |
| Rice methane (Alternate Wetting and Drying, AWD) | Emissions avoided, not carbon stored | Not reversible in the same sense |
Avoided emissions versus removals — an important distinction
Rice methane reduction is an avoided emission: methane that was never released. Once a season passes without that methane being emitted, it cannot be un-avoided. There is no equivalent reversal risk, and buffer arrangements differ accordingly.
Soil carbon and agroforestry are removals or stock increases: carbon actively held somewhere that could release it. That is where permanence rules bite hardest.
This is one genuine advantage of the rice pathway that rarely gets mentioned when pathways are compared.
How the buffer pool works
- Risk assessment. Each land-use project is assessed for reversal risk across factors including land tenure security, financial viability, governance and management capability, natural risks such as fire, drought and pest, and the likelihood that practices are discontinued.
- Withholding. A percentage of every issued batch is deposited into the registry's pooled buffer account rather than delivered to the project.
- Compensation. If any project in the programme suffers a reversal, credits are cancelled from the pool to make good the loss.
- Release. Under defined conditions and over time, some buffer credits may be released back as risk declines.
It is, in effect, a collectively funded insurance scheme — every project pays in, and the pool covers whichever projects fail.
Because the percentage is project-specific and the rules are periodically revised, the useful action is to ask a direct question rather than assume a standard number: what buffer percentage has been assessed for this project, and why? A high assessed buffer is itself informative — it tells you the registry considers this project comparatively risky.
What this means for farmers
Your quoted tonnes are gross. When someone estimates your land will generate a certain number of credits, ask whether that is before or after buffer withholding, and before or after MRV cost recovery and commission. The four numbers can differ substantially, as our look at how much farmers actually earn sets out.
Your commitment period exists because of permanence. The reason soil carbon agreements run five to ten years is not administrative preference — it is that a shorter commitment would not deliver a durable outcome. When you sign, you are agreeing to maintain practices, and that is what the buyer is paying for.
Exit clauses matter. Reversals are classified broadly as intentional — the project or farmer chose to stop — and unintentional, caused by natural events. Registries treat these differently, and enrolment agreements handle them differently too. Read what yours says about leaving early, and about what happens if a planted block fails.
You generally are not asked to repay cash. The buffer exists so reversals are covered without clawing money back from participants. But contractual consequences such as exclusion from future payments are common, so what matters is your specific agreement.
What this means for FPOs and developers
Reversal risk is largely a function of things an FPO controls:
- Tenure clarity — documented land and carbon rights lower assessed risk
- Governance capability — demonstrable management capacity lowers it further
- Farmer retention — the biggest practical risk in a smallholder programme is participants quietly reverting, which makes honest enrolment and continued engagement a technical risk-management activity, not only an ethical one
- Diversification — geographically concentrated projects carry correlated natural risk
The strategic point: a lower assessed buffer means more saleable credits from the same verified tonnage. Investment in tenure documentation, governance and farmer relationships pays back directly in issued credits, which is a rare case of doing the right thing being straightforwardly profitable.
Our MRV service covers risk assessment and permanence planning as part of project design; our advisory service covers structuring agreements that handle reversal fairly.
Want to understand what buffer and commitment terms your project would face? Request a free assessment and we'll walk through it honestly.
Current as of August 2026. Buffer and permanence rules are set by each registry and revised periodically — confirm current requirements with the registry directly before making project decisions. General information only, not financial or legal advice.
Frequently asked questions
What does permanence mean in carbon markets?
Permanence is the question of whether carbon stored today stays stored. A tonne of CO2 kept out of the atmosphere for two years is not equivalent to a tonne kept out for a century, and buyers are paying for a durable climate outcome. Land-based carbon — soil organic carbon and trees — is inherently reversible, so registries impose specific rules to manage the risk that stored carbon is released again.
What is a buffer pool?
A buffer pool is a shared reserve of credits held by a registry as insurance against reversals. Every land-use project undergoes a risk assessment, and a percentage of each credit batch is withheld and deposited into the pool rather than issued to the project. If any project in the programme suffers a reversal, credits are cancelled from the pool to compensate. It functions like a collectively funded insurance scheme for the whole registry.
How much is withheld into the buffer?
It varies by project, because it is set by a risk assessment covering factors such as land tenure security, financial viability, governance capability, natural risks like fire drought and pest, and the likelihood that practices are discontinued. Higher assessed risk means a larger withholding. Because the percentage is project-specific and rules are revised periodically, you should ask any project what buffer percentage has been assessed for it rather than assuming a standard figure.
What is a reversal?
A reversal occurs when carbon that was previously credited is released back to the atmosphere. In agriculture this could mean ploughing up land under zero tillage, resuming residue burning, or losing planted trees to fire, drought, pest or felling. Reversals are classified broadly as intentional, where the project or farmer chose to stop, or unintentional, caused by natural events, and registries treat the two differently.
Does a reversal mean farmers have to repay money?
Usually not directly, because the buffer pool exists precisely so that reversals are covered without clawing back cash from participants. However, enrolment agreements commonly commit farmers to maintaining practices for a defined period, and breaching that can carry contractual consequences including exclusion from future payments. What matters is what your specific agreement says, so read the exit and reversal clauses before signing.
Why do trees and biochar get treated differently from soil carbon?
Durability differs. Soil organic carbon can be released relatively quickly if management reverts, which makes it comparatively vulnerable. Tree carbon persists as long as the trees stand, so risk centres on survival, fire and felling. Biochar carbon resists decomposition for far longer than ordinary soil organic matter, which is why it is often regarded as a more durable removal and can attract stronger buyer interest.
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Rohan Mehta
Carbon Markets & Policy Lead
Rohan advises on methodology selection, registries, pricing and compliance — including how India’s Carbon Credit Trading Scheme (CCTS) and the EU CBAM affect agri-carbon programmes.
- Carbon markets & VVB management
- CCTS & CBAM advisory
- Offtake & price strategy