A country gets a carbon credit by reducing or removing greenhouse gas emissions through a verified project or program, then having that reduction certified and recorded in a registry. Each credit represents one metric ton of carbon dioxide (or its equivalent) that was either prevented from entering the atmosphere or actively removed from it. The process involves international rules under the Paris Agreement, independent auditing, and national-level accounting systems that track every credit to prevent double counting.
The Two Main Pathways Under the Paris Agreement
The Paris Agreement created two distinct routes for countries to generate and trade carbon credits, both housed under Article 6. The first, known as Article 6.2, allows countries to trade emission reductions directly with each other through bilateral or multilateral deals. These traded units are called Internationally Transferred Mitigation Outcomes, or ITMOs. A country that cuts emissions beyond what it pledged can sell the surplus to another country that needs help meeting its own target.
The second route, Article 6.4, establishes a centralized UN carbon market sometimes called the Paris Agreement Crediting Mechanism. This works more like a global marketplace: specific projects within a country (a wind farm, a reforestation effort, an industrial efficiency upgrade) earn credits that can be sold to other governments or to private buyers. After nearly a decade of negotiation, countries agreed at COP29 in late 2024 on the final rules making both pathways fully operational, including mandatory checks against environmental and human rights protections and safeguards requiring informed agreement from Indigenous Peoples before a project can proceed.
What a Country Needs Before It Can Participate
Before generating or trading credits, a country needs infrastructure. At a minimum, this means a national carbon registry: a digital system that tracks every credit issued, held, transferred, or retired. These registries connect to international verification systems. Under the Kyoto Protocol era, for instance, every registry linked to the International Transaction Log run by the UN, which verified transactions in real time and could block any trade that violated the rules. The Paris Agreement framework follows a similar logic, with registries recording holdings and settling trades by moving credits from seller accounts to buyer accounts.
Beyond the technical system, a country needs a legal and institutional framework for authorizing transactions. Authorization is a country-driven process, meaning each nation sets up its own domestic arrangements for deciding which credits can be transferred internationally. This matters because authorizing a transfer triggers a binding obligation: the selling country must apply what’s called a “corresponding adjustment” to its own emissions balance, effectively adding those tons back onto its books. Without this step, the same reduction could be counted by both the seller and the buyer.
How a Carbon Credit Project Gets Built
The lifecycle of a credit-generating project follows a predictable sequence, whether it’s a government initiative or a private project operating within a country’s borders.
It starts with a feasibility assessment and project design. The project developer defines objectives, methodology, and timeline, then establishes a baseline: the amount of emissions that would have occurred without the project. This baseline is the measuring stick. Everything the project achieves gets compared against it. A monitoring plan is also developed at this stage, laying out exactly how emission reductions or carbon removal will be tracked over time. Stakeholder engagement, including local communities, government agencies, and investors, happens here too.
Next comes validation and certification. An independent third-party auditor reviews the project design to confirm it meets the requirements of a recognized carbon standard. Once the project is up and running, auditors return (often annually) to verify actual results against the baseline. Only after verification are credits formally issued and made available for trading.
Implementation itself can look like anything from planting millions of trees to installing solar panels to upgrading factory equipment. Throughout the project’s life, continuous monitoring and regular reporting to the certification body keep the credits flowing. If results fall short, fewer credits get issued.
The Additionality Test
The single most important quality check for any carbon credit is additionality. A project is “additional” only if the emission reductions it delivers would not have happened without the financial incentive of selling carbon credits. If a factory was going to upgrade its equipment anyway for cost savings, credits from that upgrade aren’t truly additional, and issuing them would amount to rewarding business as usual.
This sounds straightforward in theory but gets complicated in practice. Research published in the journal Ecological Applications examined forest carbon projects credited under “improved forest management” protocols and found that several projects in ecologically diverse regions did not actually contain more carbon than would be expected under typical private management once environmental factors were properly accounted for. In other words, the baselines were set too generously, and the projects got credit for carbon storage that would have existed regardless. This kind of finding is why credible standards now require rigorous baseline setting, and why the Article 6.4 mechanism mandates alignment with the best available science.
Forest Protection as a National Strategy
One of the most significant ways developing countries generate credits is through REDD+ programs, which pay countries to reduce deforestation and forest degradation. These operate at a jurisdictional scale, meaning they cover an entire nation or large subnational region rather than a single forest plot. The World Bank’s Forest Carbon Partnership Facility has supported multiple countries in designing these programs, providing technical assistance, funding for satellite monitoring systems, frameworks for including Indigenous Peoples, and transparent benefit-sharing arrangements so that local communities actually receive financial returns.
A country participating in REDD+ needs to build national capacity for monitoring forest cover (using both ground measurements and remote sensing), establish social and environmental safeguards, and demonstrate that reduced deforestation is generating real, measurable emission reductions compared to a historical baseline. When verified, the resulting credits can be sold internationally or used as part of the country’s own climate pledge.
How Corresponding Adjustments Prevent Double Counting
The accounting backbone of the entire system is the corresponding adjustment. When Country A generates a carbon credit and sells it to Country B, Country A must add that ton of emissions back onto its own national tally. Country B subtracts it. This ensures each ton of reduction is counted only once globally.
This creates a real cost for the selling country. By transferring a credit, the host nation increases its own burden for meeting its climate pledge. If a country sells too aggressively, it risks “overselling,” leaving itself unable to meet its own targets without pursuing more expensive domestic reductions later. The World Bank has noted several pricing strategies countries can use to manage this risk, including setting prices based on the opportunity cost of the reductions being sold, or earmarking only those reductions that go beyond what the country needs for its own compliance.
Credits used in the voluntary carbon market or for purposes like offsetting international aviation emissions under CORSIA follow similar authorization and adjustment rules, though the specifics vary depending on the intended use.
Independent Certification Standards
Not all credits run through the UN system. Independent registries like Gold Standard and Verra operate their own certification processes that countries and project developers can use. Gold Standard, for example, checks projects against criteria including credible baselines and additionality, robust monitoring plans, stakeholder-inclusive design, and social and environmental safeguards. Certified projects must renew their design certification every five years, applying updated methodologies and redefining their baseline to reflect current conditions.
These independent standards are now increasingly aligning with Paris Agreement requirements. At a practical level, this means ensuring that emission reduction calculations reflect national climate policies, that carbon finance goes beyond what countries would do on their own, and that project baselines account for the host country’s existing climate targets. A credit that meets both an independent standard and Article 6 requirements can be traded in multiple markets, making it more valuable.