This section of the article provides a detailed analysis of the natural climate solutions (NCS) pathway, focusing on the maximum mitigation potential and cost-effectiveness of various natural pathways to reduce greenhouse gas emissions. The authors estimate the mitigation potential for 20 natural pathways across three biomes (forests, grasslands + croplands, and wetlands) by 2030, while considering food security and biodiversity conservation. Key findings include: 1. **Maximum Mitigation Potential**: The authors estimate the maximum annual mitigation potential for each pathway, constrained by human needs for food and fiber, and avoiding negative impacts on biodiversity. The methods used to estimate these potentials involve reviewing existing literature and conducting expert elicitation for uncertainty. 2. **Cost-Effective Mitigation Levels**: The authors determine the proportion of maximum potential NCS needed to limit global warming below 2°C and the cost-effective levels at which this can be achieved. They assume a marginal cost of approximately 100 USD per Mg of carbon dioxide equivalent emitted per year in 2030 to hold warming below 2°C. 3. **Co-Benefits**: The section also discusses the co-benefits associated with implementing NCS, such as enhanced ecosystem services like biodiversity, water regulation, soil quality improvement, and air quality regulation. 4. **Country-Level Mitigation**: The authors map the mitigation potential for each pathway at the country level, considering the extent and flux per hectare of each pathway. 5. **Uncertainty Analysis**: The uncertainty in the maximum mitigation potential estimates is addressed through empirical methods and expert elicitation, providing a range of possible outcomes. 6. **Mitigation Targets**: Specific targets for avoided forest conversion, reforestation, and natural forest management are set, aligning with global agreements and commitments such as the UN Declaration on Forests and the Paris Agreement. The analysis aims to provide a comprehensive understanding of the potential and challenges of NCS in contributing to climate mitigation efforts.This section of the article provides a detailed analysis of the natural climate solutions (NCS) pathway, focusing on the maximum mitigation potential and cost-effectiveness of various natural pathways to reduce greenhouse gas emissions. The authors estimate the mitigation potential for 20 natural pathways across three biomes (forests, grasslands + croplands, and wetlands) by 2030, while considering food security and biodiversity conservation. Key findings include: 1. **Maximum Mitigation Potential**: The authors estimate the maximum annual mitigation potential for each pathway, constrained by human needs for food and fiber, and avoiding negative impacts on biodiversity. The methods used to estimate these potentials involve reviewing existing literature and conducting expert elicitation for uncertainty. 2. **Cost-Effective Mitigation Levels**: The authors determine the proportion of maximum potential NCS needed to limit global warming below 2°C and the cost-effective levels at which this can be achieved. They assume a marginal cost of approximately 100 USD per Mg of carbon dioxide equivalent emitted per year in 2030 to hold warming below 2°C. 3. **Co-Benefits**: The section also discusses the co-benefits associated with implementing NCS, such as enhanced ecosystem services like biodiversity, water regulation, soil quality improvement, and air quality regulation. 4. **Country-Level Mitigation**: The authors map the mitigation potential for each pathway at the country level, considering the extent and flux per hectare of each pathway. 5. **Uncertainty Analysis**: The uncertainty in the maximum mitigation potential estimates is addressed through empirical methods and expert elicitation, providing a range of possible outcomes. 6. **Mitigation Targets**: Specific targets for avoided forest conversion, reforestation, and natural forest management are set, aligning with global agreements and commitments such as the UN Declaration on Forests and the Paris Agreement. The analysis aims to provide a comprehensive understanding of the potential and challenges of NCS in contributing to climate mitigation efforts.