What Is Article 6 of the Paris Agreement? A Guide to International Carbon Markets

Article 6 of the Paris Agreement is the framework enabling international cooperation on climate targets through carbon market mechanisms. It allows countries to trade emission reductions and removals, helping them meet their Nationally Determined Contributions (NDCs) more cost-effectively while channeling climate finance to projects worldwide.

Adopted in 2015 but only fully operationalized at COP29 in November 2024, Article 6 represents a decade of complex negotiations under the UNFCCC. Understanding its mechanisms is essential for anyone navigating the evolving landscape of international carbon markets.

The Three Mechanisms Under Article 6

Article 6 establishes three distinct approaches for international climate cooperation, each serving different purposes.

• Article 6.2 enables bilateral and multilateral agreements between countries. Under this framework, nations can trade Internationally Transferred Mitigation Outcomes (ITMOs), which are emission reductions or removals transferred between countries. As of December 2025, 176 pilot activities have been recorded under Article 6.2. Switzerland and Thailand completed the first ITMO transfer in 2024, setting a precedent for country-to-country carbon trading.

• Article 6.4 establishes a centralized, UN-supervised carbon crediting mechanism known as the Paris Agreement Crediting Mechanism (PACM). This replaces the Clean Development Mechanism (CDM) from the Kyoto Protocol era. The Article 6.4 Supervisory Body oversees methodology approval, project registration, and registry management. In late February 2026, the UN issued the first credits under this mechanism, marking a historic milestone for international carbon markets.

• Article 6.8 provides a non-market framework where countries can support each other's climate efforts without trading credits, focusing on technology transfer and capacity building.

First Article 6.4 Credits Signal Stricter Standards

The inaugural Article 6.4 issuance came from a clean cooking project in Myanmar that distributes improved cookstoves to reduce household air pollution and pressure on forests. The credits were authorized for transfer to the Republic of Korea, where they will count toward both the country's NDC and its domestic emissions trading system.

Notably, the new mechanism applies more conservative calculations than its predecessor. The credited reductions were approximately 40% lower than what the CDM would have issued for the same project. This reflects stricter environmental integrity requirements under the Paris Agreement, including updated baseline methodologies and more rigorous quantification standards. The mechanism also includes a mandatory 5% share of proceeds directed to the Adaptation Fund and a minimum 2% cancellation requirement for overall mitigation.

How Corresponding Adjustments Prevent Double Counting

A critical integrity safeguard in Article 6 is the corresponding adjustment mechanism. When one country transfers emission reductions to another, the host country must adjust its emissions accounting to reflect the transfer. This prevents double counting, where the same reduction is claimed by multiple parties.

For example, if Country A sells ITMOs to Country B, Country A must add those emissions back to its national inventory while Country B subtracts them. This accounting ensures the global emissions balance remains accurate and that traded reductions represent real climate benefits.

Key Takeaway

Article 6 of the Paris Agreement provides the architecture for international carbon trading under UN oversight. With 78% of countries indicating plans to use Article 6 mechanisms in their NDCs, these frameworks will increasingly shape global carbon market dynamics. The first Article 6.4 issuance demonstrates that the system is now operational, with integrity standards that exceed those of the Kyoto era. For buyers, developers, and policymakers, understanding the distinctions between Article 6.2 and 6.4, and the integrity safeguards underpinning them, is now essential for navigating compliance and voluntary market participation.