Article 6 of the Paris Agreement is a fundamental pillar of international climate policy. It provides a formal structure through which countries can cooperate to achieve their climate goals, by using both market-based and non-market approaches. The design of Article 6 is intended to ensure that cooperation is real, measurable, and contributes with integrity to global mitigation ambition.

The Purpose of Article 6

The main purpose of Article 6 is to foster voluntary cooperation between countries in order to deliver their Nationally Determined Contributions (NDCs) more cost-effectively, while simultaneously promoting sustainable development. By enabling the transfer of emission reductions and encouraging non-market collaboration, Article 6 supports greater ambition, increased climate finance, and stronger global partnerships.(1)

Importantly, Article 6 also seeks to preserve environmental integrity. This is achieved through accounting rules, particularly “corresponding adjustments”, to prevent the same emissions reduction from being claimed by more than one party.(2)

The Three Mechanisms of Article 6

Article 6 is composed of three sub-articles, each offering a different but complementary path for cooperation: 6.2, 6.4, and 6.8.

1. Article 6.2 – Cooperative Approaches

Under Article 6.2, countries may engage in bilateral or multilateral agreements to transfer emissions reductions. These reductions are quantified as Internationally Transferred Mitigation Outcomes (ITMOs).(3)

In practice, one country can finance or support a mitigation activity in another country. The reductions achieved by that activity – once authorised – can then be transferred to the financing country and counted toward its NDC. This flexibility allows for very tailored cooperation. 

However, to guard against double counting, the framework requires corresponding adjustments. When a mitigation outcome is transferred, the seller country adjusts its national emissions ledger (or its NDC accounting) downward; the buyer country adjusts upward.(4)

Cooperative approaches under Article 6.2 are meant to be transparent, with reporting and accounting obligations.(5)

2. Article 6.4 – The Paris Agreement Crediting Mechanism

Article 6.4 establishes a centralised, United Nations-supervised mechanism to generate tradable carbon credits. This mechanism is sometimes referred to as the Paris Agreement Crediting Mechanism.(6)

Credits created under this mechanism are known as A6.4ERs (Article 6.4 Emission Reductions). These credits may be generated from a variety of mitigation activities—such as renewable energy deployment, deforestation avoidance, or industrial gas destruction.(7)

The governance of this mechanism is handled by a Supervisory Body under the UNFCCC. That body is tasked with setting rules, ensuring transparency, and reviewing activity submissions. (8)

One of the design principles is that projects under Article 6.4 should contribute to sustainable development in host countries, not just generate emissions reductions.(9)

Like in 6.2, corresponding adjustments are required when credits are used toward NDCs, in order to maintain environmental integrity.(10)

Moreover, a share of the proceeds from these projects is often reserved for adaptation finance in developing countries, which helps address climate vulnerability. (11)

3. Article 6.8 – Non-Market Approaches

Article 6.8 recognises that not all climate cooperation must involve trading carbon credits. It provides a formal framework for non-market approaches, such as capacity-building, technology transfer, finance, and shared policy design.(12)

These approaches are voluntary. Participating countries can collaborate on sustainable development initiatives that contribute to mitigation, adaptation, or both — without the exchange of mitigation outcomes. (13)

Key aims of Article 6.8 include:

• Promoting both mitigation and adaptation ambition(14)
• Strengthening public and private sector participation in national climate plans(14)
• Facilitating coordination across different governance structures and financial instruments 

To support this cooperation, the UNFCCC has established the Glasgow Committee on Non-market Approaches (GCNMA). This committee has initiated a work programme to encourage and guide non-market climate collaboration. 

There is also an NMA (Non-Market Approaches) Platform, which allows Parties and stakeholders to register non-market cooperation activities, share information, request support, and coordinate their efforts. 

Advantages of Article 6 Mechanisms

• Cost Efficiency: Allowing emissions reductions to be achieved in countries where they are most cost-effective can lower the overall cost of mitigation.(16)
• Stimulating Climate Finance: The mechanisms help channel investment into mitigation activities, particularly in developing countries.(17)
• Ensuring Environmental Integrity: Robust accounting and the use of corresponding adjustments reduce the risk of double counting.
  
• Encouraging Broad Cooperation: By providing non-market paths as well, Article 6 supports inclusive collaboration — not just through trade, but through capacity-building, technology sharing, and more.
  
• Promoting Sustainable Development: Projects under Article 6 often carry co-benefits, such as job creation, clean energy deployment, or adaptation support.
  

Challenges and Criticisms

Despite its promise, Article 6 is not without controversy:

1. Double Counting Risks: Even with corresponding adjustments, there remain practical risks that some parties may not account properly, undermining environmental credibility.
   
2. Quality of Credits: The integrity of credits generated under Article 6.4 depends on rigorous methodologies. Poorly designed credits risk being non-additional or over-claimed.
   
3. Equity Concerns: Critics argue that wealthier countries could outsource emission reductions without decarbonizing their own economies — raising ethical and developmental questions.
   
4. Institutional Capacity: Implementing robust accounting, registry systems, and supervisory institutions requires capacity that some developing countries may struggle to build. 

The Evolving Landscape

Since COP 26, significant progress has been made in finalising the rulebook for Article 6. However, some technical and institutional challenges remain. 

The full effect of Article 6 will likely depend on how well countries operationalise its mechanisms and maintain integrity. If implemented robustly, the system could become a major driver of international climate cooperation, channeling finance, technology, and ambition where they are most needed.

Conclusion

Article 6 of the Paris Agreement stands as a central framework for collective climate action. By combining market-based cooperation (via Articles 6.2 and 6.4) with non-market collaboration (Article 6.8), it offers nations multiple pathways to meet their NDCs while promoting sustainable development. The success of Article 6 will depend on robust accounting, transparency, and the willingness of countries to support high-quality mitigation and resilient development efforts