CARBON CREDIT PERMANENCE: RISKS, REVERSALS AND SAFEGUARDS

Permanence describes how long the climate benefit represented by a carbon credit is expected to last.

For projects that remove and store carbon dioxide, it reflects the level of confidence that the stored carbon will remain out of the atmosphere for decades, centuries or longer. For projects that protect existing carbon stocks, such as forest conservation projects, permanence concerns whether that protection can be maintained and whether the carbon will remain stored.

This matters because carbon stored in forests, soils or other reservoirs can be released again. A wildfire, illegal logging, land conversion or change in land management can reverse some or all of the climate benefit for which credits were previously issued.

Permanence is therefore not simply a project duration. It is the combination of storage durability, long-term monitoring, reversal-risk management and credible compensation mechanisms.

There is no single, market-wide definition of how long carbon must remain stored for a credit to be considered permanent.

Requirements differ between carbon standards, methodologies and project types. Under Verra’s Verified Carbon Standard, for example, relevant Agriculture, Forestry and Other Land Use projects registered under newer requirements must establish a minimum project longevity period of 40 years together with associated monitoring and compensation arrangements.

This requirement should not be treated as a universal rule for the entire voluntary carbon market. Other carbon standards may apply different monitoring periods, liability requirements and approaches to reversal risk.

Different carbon removal pathways also provide different levels of durability. Carbon stored in a living forest is exposed to different risks from carbon stored underground or converted into a stable mineral form.

Permanence is therefore best understood as a spectrum. The relevant questions are:

• How durable is the underlying carbon storage?
• Which events could reverse the climate benefit?
• How likely and severe are those events?
• How long will the project be monitored?
• What happens if a reversal occurs?

Who remains responsible over the long term? 

A carbon credit only represents a lasting climate outcome if its benefit is maintained over time.

If carbon is removed from the atmosphere and then released again a few years later, the original benefit is weakened or lost. The same applies when a forest protection project prevents deforestation temporarily, but the protected area is later cleared.

Permanence is particularly important because the warming effect of carbon dioxide emissions extends over very long periods. A temporary removal cannot automatically be treated as equivalent to permanently preventing an emission.

Weak permanence can expose carbon credit buyers to several risks:

• overstated climate impact
• weakened climate claims
• reputational damage
• financial exposure
• future replacement or compensation obligations
• criticism that short-term storage has been presented as a lasting solution

A credible carbon credit must therefore address both the initial climate result and the risk that this result may later be reversed. 

A reversal occurs when carbon that was previously removed from the atmosphere or protected from release enters the atmosphere at a later point.

Examples include:

• a forest burning after carbon removal credits have been issued
• illegal logging within a protected project area
• restored land being converted to agriculture
• peatland being drained again
• farmers discontinuing soil-carbon practices
• mangroves being damaged by coastal development
• trees in an agroforestry system being removed
• stored carbon leaking from a geological reservoir

Reversals may be caused by natural events, human activity or a combination of both.

Some reversals are considered unavoidable, such as losses caused by an extreme natural disaster despite appropriate risk management. Others may be considered avoidable if they result from poor management, insufficient enforcement or failure to fulfil project obligations.

This distinction can affect how the reversal is compensated and whether the project remains eligible to issue further credits. 

Permanence is assessed through a combination of technical analysis, risk modelling, monitoring obligations, legal commitments and system-level safeguards.

A robust assessment should examine both the physical durability of the carbon storage and the project’s practical capacity to protect it.

IDENTIFYING REVERSAL RISKS

The first step is to identify credible events that could cause carbon losses.

Depending on the project, these may include:

• wildfire
• drought
• storms and flooding
• pests and disease
• illegal logging
• land conversion
• changes in land ownership or tenure
• political or regulatory changes
• conflict
• loss of community support
• project insolvency
• insufficient long-term financing
• failure of monitoring or enforcement systems

The analysis should reflect the project’s specific ecosystem, location, management model and social context rather than relying only on generic assumptions.

ESTIMATING PROBABILITY AND POTENTIAL LOSS

The project must assess how likely each risk is and how much stored carbon could be affected.

A low-probability event that could destroy most of a project’s carbon stock may still be highly material. Likewise, repeated smaller losses can create a significant cumulative risk.

Carbon standards may convert the resulting risk score into a required buffer contribution, insurance requirement or discount applied to the number of credits issued.

ASSESSING LAND RIGHTS AND LONG-TERM CONTROL

Permanence depends heavily on whether the project has a credible basis for managing the land and carbon stock over time.

Relevant questions include:

• Are land and carbon rights clearly defined?
• Do contractual commitments cover the required period?
• Can the project enforce restrictions on land use?
• What happens if the land is sold?
• Are Indigenous Peoples and local communities meaningfully involved?
• Do local stakeholders benefit from maintaining the project?
• Is there a mechanism for resolving disputes?

Long project durations alone do not guarantee permanence if the underlying rights, incentives and responsibilities are weak.

EVALUATING LONG-TERM FINANCING

Monitoring, enforcement and stakeholder engagement require continued funding.

A permanence assessment should therefore examine whether the project has a credible financial plan for activities such as:

• field monitoring
• satellite monitoring
• fire prevention
• restoration after damage
• community engagement
• legal enforcement
• verification
• reporting
• project governance

A project that depends on continuous protection but lacks long-term financing may present a material permanence risk.

MONITORING AND VERIFICATION

Projects must monitor carbon stocks over time and report significant losses.

Monitoring may combine:

• permanent field plots
• forest inventories
• soil sampling
• remote sensing
• satellite-based alerts
• drone imagery
• hydrological monitoring
• ecological surveys
• periodic third-party verification

Carbon standards should also define what constitutes a reversal, how quickly it must be reported, how the affected volume is calculated and how compensation is triggered.

Permanence is not the same for every carbon credit.

The nature of the risk depends on whether the project avoids emissions, removes carbon and stores it biologically, or stores it in a more durable physical or geological form.

NATURE-BASED CARBON REMOVALS

Afforestation, reforestation, improved forest management, agroforestry and soil-carbon projects store carbon in living biomass or soils.

These reservoirs can provide substantial climate benefits, but they remain exposed to ecological, climatic and human-driven change. Their permanence depends on continued management, protection and monitoring.

AVOIDED DEFORESTATION AND OTHER NATURE-BASED AVOIDANCE PROJECTS

Avoided deforestation projects do not remove carbon that has already entered the atmosphere. Instead, they seek to prevent the release of carbon stored in existing forests.

They nevertheless face a permanence-related risk. If protection later fails and the forest is cleared, the emissions that the project sought to avoid may still occur.

ENGINEERED AND GEOLOGICAL CARBON REMOVALS

Direct air capture with geological storage, enhanced weathering, mineralisation and some biochar pathways can offer storage lasting centuries or potentially millennia.

However, durability varies by technology, storage environment and methodology. These approaches still require credible measurement, monitoring and liability arrangements.

Longer theoretical storage duration does not remove the need to assess operational failure, leakage, measurement uncertainty or responsibility for future monitoring.

NON-LAND-BASED EMISSION-REDUCTION PROJECTS

Some projects reduce emissions without creating a stored carbon stock. Examples may include the destruction of certain industrial gases, methane capture or activities that replace a higher-emission process.

Because no new carbon reservoir is created, the same physical reversal risk may not apply. However, these projects still require robust additionality, baseline setting, quantification and monitoring.

Nature-based projects share certain risks, but their relevance differs significantly by ecosystem and project activity.

FORESTRY PROJECTS

Afforestation, reforestation and revegetation projects may face risks from:

• wildfires
• drought
• pests and disease
• low tree survival
• storms
• future harvesting
• land conversion
• insufficient maintenance
• insecure land tenure

Improved forest management projects also depend on whether changes in harvesting intensity, rotation periods and silvicultural practices are maintained over time. Market pressure can create incentives to return to more intensive extraction.

REDD+ and avoided-deforestation projects face additional governance and enforcement risks, including:

• illegal logging
• agricultural expansion
• changing commodity prices
• infrastructure development
• weak enforcement
• political instability
• changes in land-use policy
• conflicts over land and resource rights

AGROFORESTRY AND AGRICULTURAL LAND PROJECTS

Permanence in agroforestry depends on continued farmer participation, viable farm economics and the survival of trees within productive landscapes.

Risks may include:

• removal of trees when commodity prices change
• farm succession
• land sales
• changes in subsidies
• drought and heat stress
• shifts in production systems
• insufficient benefits for participating farmers

Soil carbon can be particularly sensitive to management changes. A return to intensive tillage, reduced cover cropping or altered grazing pressure can cause previously stored carbon to be released.

Soil-carbon gains may also be difficult to measure because carbon levels vary across space and time. A project must therefore distinguish genuine long-term storage from short-term variability.

BLUE CARBON PROJECTS

Mangroves, salt marshes and seagrass ecosystems can store substantial amounts of carbon, particularly in their soils.

Their permanence is influenced by coastal processes and hydrology. Risks include:

• storm damage
• coastal erosion
• sea-level rise
• disrupted sediment supply
• changes in freshwater flows
• declining water quality
• conversion to aquaculture
• coastal development
• shifting land tenure and permits

Hydrological integrity is especially important. If tidal exchange, freshwater inflows or sediment processes are disrupted, the ecosystem may degrade and release stored carbon.

PEATLAND PROJECTS

Peatlands contain highly concentrated carbon stocks. When peatlands are drained, the peat is exposed to oxidation and fire, which can generate large emissions.

Rewetting can reduce these risks, but permanence depends on maintaining appropriate water levels and preventing future drainage.

A failure of water-management infrastructure, renewed agricultural pressure or severe drought may undermine the project’s climate benefit.

GRASSLAND AND SAVANNA PROJECTS

Grasslands and savannas may store substantial carbon below ground and can be resilient under appropriate management.

Risks include:

• conversion to cropland
• overgrazing
• invasive species
• inappropriate fire management
• soil degradation
• changes in grazing practices
• infrastructure development

Where credits depend on soil-carbon increases, those gains may reverse when management practices change

No single safeguard can eliminate permanence risk. Credible projects combine multiple layers of protection.

LONG-TERM MONITORING

Projects should continuously monitor carbon stocks and the conditions that could affect them.

Early-warning systems can help identify forest loss, fires, hydrological change or other threats before losses become more severe.

EFFECTIVE RISK PREVENTION

Risk reduction should be tailored to the project and may include:

• firebreaks and fire-management plans
• pest and disease monitoring
• restoration of degraded areas
• diversified planting
• water-management systems
• protection against illegal logging
• improved land-use planning
• climate-resilient species selection
• clear emergency-response procedures

STRONG LOCAL INCENTIVES

The long-term participation of Indigenous Peoples, local communities, landowners and farmers is often fundamental to permanence.

Projects are more likely to endure when local stakeholders receive credible and fairly distributed benefits, such as:

• improved livelihoods
• employment
• access to finance
• stronger land rights
• technical support
• resilient agricultural systems
• transparent revenue sharing

Community involvement should not be treated solely as a social co-benefit. It is also a core element of long-term risk management.

CLEAR RIGHTS AND CONTRACTUAL COMMITMENTS

Land rights, carbon rights and project responsibilities should be clearly documented.

Contracts should address:

• the duration of commitments
• changes in land ownership
• monitoring access
• liability for avoidable reversals
• use of project revenues
• dispute resolution
• responsibilities after the crediting period

BUFFER POOLS AND INSURANCE

A buffer pool is a reserve of credits that are withheld rather than sold.

If a qualifying reversal occurs, an equivalent number of buffer credits may be cancelled to compensate for the loss at the program-accounting level.

Under Verra’s Verified Carbon Standard, relevant land-use projects contribute to a shared buffer pool based on their assessed non-permanence risk. This pooled structure spreads risk across multiple projects rather than linking every buyer directly to an individual loss event.

Buffer pools reduce risk, but they are not proof that risk has disappeared. Their effectiveness depends on factors such as:

• the quality of risk assessments
• the size of contributions
• the independence of project risks
• the treatment of correlated climate events
• the accuracy and speed of reversal detection
• governance of the shared reserve
• whether the pool can withstand multiple large losses

Insurance and other financial guarantees may provide an additional layer of protection, but their terms, duration and exclusions require careful review.

REVERSAL-RESPONSE PROCEDURES

Standards and projects should establish in advance:

• how reversals are detected
• who must report them
• how losses are quantified
• when buffer credits are cancelled
• whether the project must make additional contributions
• how avoidable and unavoidable reversals are treated
• whether credit issuance will be suspended

Clear procedures reduce uncertainty when a loss occurs.

Permanence and additionality answer different questions.

Additionality asks whether the emission reduction or carbon removal would have happened without the project and carbon finance.

Permanence asks whether the climate benefit will last after it has been achieved.

Both conditions must be met.

A project may be genuinely additional when credits are issued but still fail to deliver its promised benefit if the carbon is later released. Conversely, a highly durable carbon stock does not generate an additional climate benefit if the activity would have happened anyway.

Strong performance in one area cannot compensate for failure in the other. Permanence and additionality are therefore separate but interconnected foundations of carbon credit integrity.