What Is a Carbon Credit?

Industrial operations are where many discussions about carbon markets and greenhouse-gas reductions begin

A carbon credit is a unit created so that a greenhouse-gas reduction or removal can be transferred and traded. One credit generally represents one tonne of carbon dioxide equivalent (1 tCO₂e) reduced or removed from the atmosphere.

Consider a project that replaces fossil-fuel power with renewable energy, captures methane from a landfill, or restores degraded forest. The project calculates the greenhouse gases actually avoided against what would have happened without it. After third-party verification and registry issuance, that outcome becomes a carbon credit.

The core of a carbon credit is not the claim that a “good environmental project” took place. It is the ability to demonstrate, in a common unit, how much additional mitigation occurred and what evidence supports the result.

Where did carbon credits begin?

The roots of carbon credits reach back to the UN Framework Convention on Climate Change (UNFCCC), adopted in 1992, and the Kyoto Protocol, adopted in 1997. The international community agreed to act together on climate change, but the cost and conditions of reducing emissions differed by country and region.

The Kyoto Protocol set legally binding reduction targets for developed countries and established market mechanisms: international emissions trading, Joint Implementation (JI) and the Clean Development Mechanism (CDM). The aim was to direct finance to places where reductions could be achieved and recognize those outcomes in common units. UNFCCC Kyoto Protocol

The CDM in particular allowed developed countries to participate in mitigation projects in developing countries and receive Certified Emission Reductions (CERs) for verified results. One CER represented one tonne of CO₂. The basic structure used today—project registration, approved methodology, demonstration of additionality, monitoring, verification and issuance—became established internationally through this process. UNFCCC Clean Development Mechanism

Carbon credits were therefore never merely eco-friendly certificates. They developed as a policy instrument that measures mitigation outcomes, converts them into verifiable units and connects international cooperation with climate finance.

What did the Paris Agreement change?

The Paris Agreement, adopted in 2015, moved to a system in which nearly every country sets and implements its own nationally determined contribution (NDC). When a mitigation outcome generated in one country is used by another country or a company, it becomes critical to determine who may count that outcome.

Article 6 provides a framework for voluntary cooperation among countries:

• Article 6.2 addresses authorization, accounting and reporting for mitigation outcomes transferred between countries.
• Article 6.4 establishes a new international crediting mechanism supervised by the UNFCCC.
• Article 6.8 addresses non-market approaches to international cooperation.

A central principle is preventing double counting. If both the host and acquiring country claim the same reduction, global mitigation is overstated. Host-country authorization and accounting procedures such as corresponding adjustments are therefore important for internationally transferred mitigation outcomes. UNFCCC Article 6 of the Paris Agreement

The Article 6.4 mechanism is building an international framework for methodologies, registration, verification, issuance and transfer based on these principles. UNFCCC Paris Agreement Crediting Mechanism

How mitigation outcomes are authorized, issued and transferred under Article 6.4. Source: UN Climate Change, Paris Agreement Crediting Mechanism

How is a carbon credit created?

Take a project that captures and treats methane from a landfill. Installing methane-recovery equipment alone does not immediately produce credits.

The project first determines the baseline quantity of methane that would have been released without the project. It must show that the activity creates additional mitigation beyond common practice or legal requirements. It then collects field data—such as recovered methane volume and concentration and equipment operating hours—under an approved methodology and calculates actual reductions.

This requires MRV:

• Monitoring: continuously collecting and managing activity data such as gas flow, concentration and operating hours;
• Reporting: documenting the methodology, calculations and supporting evidence; and
• Verification: having an independent body confirm the validity of source data and calculations.

Verified reductions are issued as credits after review by the relevant carbon standard and registry. Transfers are recorded in the registry, and credits are cancelled or retired upon final use so they cannot be reused.

Applying digital technology to this process creates DMRV. DMRV connects source data from sensors and meters with calculations, evidence and change history in a digital environment to create a verifiable data flow. What Is DMRV? explains how DMRV connects corporate operating data with carbon-credit issuance.

DMRV does not automatically issue credits. Eligibility depends on the applicable standard and methodology, independent verification and registry review. DMRV improves the reliability and traceability of the data needed for those decisions.

Why are carbon credits becoming more important now?

First, after the Paris Agreement, carbon credits are more closely connected to national targets and international cooperation. It is no longer enough to show that a reduction occurred; users must also explain which country claims the outcome and how double counting is prevented.

Second, carbon credits are a climate-finance instrument. Renewable-energy, methane-reduction, forest-protection and carbon-removal projects that require large upfront investment or lack conventional commercial viability can secure additional finance through credit revenue. Credit purchases should complement, not replace, direct reductions by companies and countries.

Third, eligible carbon credits play an expanding role in sector-specific regulation such as international aviation. ICAO's CORSIA is a global market-based measure for international aviation emissions. Airlines cannot use just any credit; units must meet detailed conditions concerning approved programs, vintages, project scope and host-country attestation. Rules also define the units eligible for the 2024–2026 first phase. ICAO CORSIA · ICAO Eligible Emissions Units for 2024–2026

The increasing importance of carbon credits therefore means more than higher trading volume. As credits connect with national targets, sectoral regulation and corporate climate strategies, demonstrating policy- and regulation-aligned quality becomes more important.

What makes a carbon credit trustworthy?

Not every credit has the same quality or value. The conditions behind the stated tonne matter as much as the number itself.

• Is the reduction additional—would it not have occurred without the project?
• Are the baseline and calculation methodology sound?
• Can source data and supporting evidence be reviewed?
• Did an independent body verify the result?
• For storage projects such as forestry, will the benefit remain long enough?
• Has the project shifted emissions elsewhere through leakage?
• Has the same outcome been issued or used twice?
• Are issuance, transfer and retirement recorded in a registry?
• For compliance use, does the unit meet the required authorization and eligibility conditions?

A carbon credit converts an invisible mitigation outcome into a unit. Trust therefore does not come from a name or label alone, but from connected data, methodology, verification and accounting procedures.

What ultimately matters is the evidence behind the reduction

Carbon credits can channel climate-action finance to real mitigation projects. But turning weakly supported claims into numbers can undermine trust in the entire market.

Through Samton-DMRV, Samton connects source-data collection, reduction calculations, evidence management and verification reporting in one data flow.

The starting point for a trustworthy carbon market is not only the final credit figure, but the ability to explain where it came from, which rules were applied and how it was verified.

For the history and differences among major crediting programs, see Carbon Credit Standards: Their History and Role. For a closer comparison of allowances and credits and the limits on credit use in some compliance systems, continue to How Carbon Allowances Differ from Carbon Credits.