Carbon markets are becoming more sophisticated as standards, national policy frameworks and carbon-accounting approaches continue to develop, placing greater emphasis on the evidence used to support claims of emissions reductions and removals.

For project developers, investors and buyers, the central question is therefore no longer only whether a project can generate carbon credits, but how confidently the underlying climate outcome can be quantified, attributed to the project and maintained over the period for which it is claimed. This is increasing the importance of additionality, baseline setting, measurement, durability, safeguards and the treatment of mitigation outcomes within national climate policy.

Three developments illustrate this broader shift particularly well: stronger carbon-credit integrity requirements, the growing practical relevance of Article 6 and continued progress in the measurement and accounting of carbon removals.

Integrity depends on the strength of the underlying claim

Carbon-market integrity is sometimes discussed as though certification alone establishes the quality of a credit, whereas in practice certification forms part of a broader assurance process built on the methods, data and governance arrangements supporting the underlying mitigation claim.

A credible carbon credit therefore depends on a coherent chain of evidence. The mitigation activity needs to generate an emissions reduction or removal which would not otherwise have occurred, while the baseline against which that outcome is quantified needs to be well supported and uncertainties addressed conservatively. Leakage needs to be accounted for where relevant and, where carbon storage may be reversed, suitable mechanisms are needed to address that possibility over time.

The same principle applies to safeguards and governance, because carbon accounting does not operate independently of land rights, stakeholder participation, benefit sharing and environmental impacts. These considerations affect the credibility of the overall project, even where the underlying carbon calculations are technically sound.

This broader interpretation of integrity is increasingly reflected in carbon-market frameworks. The Integrity Council for the Voluntary Carbon Market’s Core Carbon Principles address additionality, permanence, robust quantification, double counting, independent validation and verification, transparency and safeguards. Verra’s VCS Version 5 follows a similar direction, with strengthened requirements relating to stakeholder engagement, safeguards, rights to emission reductions and removals, benefit sharing and baseline reassessment.

The practical implication is that confidence in a carbon credit depends on much more than the programme under which it was issued. Buyers and investors increasingly need to understand how the baseline was established, how additionality was demonstrated, how uncertainty was treated, how monitoring will detect change and how durability is addressed. For developers, this means that the foundations of a credible carbon claim are established during feasibility and project design, well before validation or verification begins.

Article 6 connects project development with national climate policy

Article 6 adds a further dimension because some carbon transactions depend not only on project performance, but also on the policy and institutional systems of the host country.

Under Article 6.2, countries can cooperate through internationally transferred mitigation outcomes, with participating countries applying agreed approaches to authorisation, tracking, reporting and corresponding adjustments where required. This makes national policy and institutional readiness directly relevant to projects seeking to participate in Article 6 transactions.

A project may have strong mitigation potential and a suitable crediting methodology, yet its ability to transact internationally can still depend on whether the host country has established clear procedures for authorisation, carbon rights, corresponding adjustments and international transfer. Where those systems are well defined, they can provide greater certainty regarding what types of mitigation activities may be authorised, how outcomes will be accounted for and what administrative steps developers and buyers need to follow.

Article 6 readiness therefore extends beyond the existence of a national carbon-market policy. What matters is whether the institutional system can support the authorisation, accounting, reporting and transfer of mitigation outcomes in a consistent manner, while remaining aligned with the country’s nationally determined contribution and wider climate-policy objectives.

This distinction is important because Article 6 does not apply uniformly to all voluntary carbon-market activity. A voluntary credit does not automatically require host-country authorisation or a corresponding adjustment, since their relevance depends on the intended use of the mitigation outcome, applicable programme rules and the host country’s policy framework.

For project developers, this changes the way feasibility needs to be assessed. Biophysical mitigation potential and methodological eligibility remain central, but projects seeking international transfer also need to consider the national policy environment within which those outcomes will be authorised, accounted for and ultimately used.

Carbon removals place greater emphasis on measurement

Carbon removals raise a related but distinct set of accounting questions because the category includes activities with very different removal mechanisms, storage reservoirs and monitoring requirements, ranging from afforestation and soil carbon management to biochar, enhanced weathering and direct air capture.

Despite these differences, a removal claim has two fundamental components: carbon needs to be removed from the atmosphere and the resulting carbon needs to remain stored for a defined period. Both components require evidence, although the form of that evidence varies considerably between pathways.

A soil-carbon project, for example, may need to distinguish genuine changes in carbon stocks from substantial spatial and temporal variability, while an afforestation project needs to quantify biomass accumulation alongside leakage and potential reversals. Enhanced weathering requires evidence that mineral application has resulted in additional atmospheric CO₂ removal, rather than simply demonstrating that material has been applied. Direct air capture allows relatively direct measurement of captured CO₂, but still requires accounting for energy use, transport and the subsequent storage of the captured carbon.

Durability adds another layer because different carbon reservoirs behave very differently over time. Carbon stored in vegetation may be affected by disturbance, harvesting or land-use change, while soil carbon can decline if management changes. Geological and mineral storage have different monitoring requirements and storage characteristics, which means they cannot be assessed using the same assumptions or timescales.

For this reason, carbon-removal accounting cannot be reduced to the number of tonnes reported as removed. It needs to establish what was measured, how the counterfactual was defined, how uncertainty was treated, where the carbon is stored and how continued storage will be demonstrated over the relevant period.

Monitoring, reporting and verification therefore form part of the technical basis of the removal claim itself, because without sufficiently robust measurement and accounting it is not possible to determine with confidence how much atmospheric CO₂ has been removed or how durable that removal is likely to be.

From carbon credits to evidence

Taken together, these developments point to a broader change in how carbon credits are assessed and understood.

The unit being transferred may be a carbon credit, but its value as a climate instrument depends on the evidence supporting the underlying mitigation outcome. That confidence is built through a connected set of elements, including a credible counterfactual, additional mitigation, conservative quantification, appropriate treatment of uncertainty and leakage, effective safeguards, transparent governance and, where relevant, consistent national accounting.

Different project types require different forms of evidence, which means there is no single technical template for demonstrating credibility across all carbon activities. The central question is whether the accounting, monitoring and governance systems are appropriate to the activity and sufficiently robust to support the claim being made.

For developers, this means designing projects around the evidence needed to substantiate their climate outcomes rather than treating measurement and assurance as later-stage requirements. For governments, it means establishing policy and accounting systems which provide clarity on how mitigation outcomes can be authorised and transferred. For buyers and investors, it means understanding the basis on which each carbon claim has been quantified, verified and maintained.

The direction of travel is therefore not simply towards more detailed rules, but towards a carbon market in which confidence rests increasingly on the quality, transparency and consistency of the evidence supporting each credit.