Global Afforestation Carbon Sequestration Potential Within an Integrated Environmental Protection and Sustainable Food System Framework

Afforestation is a high-potential and cost-effective climate change mitigation strategy, but its large-scale implementation raises sustainability concerns. It requires extensive areas of land, potentially conflicting with agriculture and impacting food security. Moreover, inappropriate forest expansion, such as the afforestation of naturally open habitats, could reduce habitats for non-forest organisms and may cause biodiversity loss. Here, we assess the global mitigation potential of afforestation by integrating environmental constraints and sustainable food system transformations within an integrated assessment model framework. Using the Asia-Pacific Integrated Model (AIM), including the AIM-Hub general equilibrium model and AIM-PLUM spatial land use allocation model, we evaluated seven scenarios incorporating biodiversity protection, soil quality enhancement, dietary shifts, food waste reduction, trade, and irrigation intensification. We found that environmental considerations reduce the maximum afforestation potential to 2.13 GtCO2 yr−1, highlighting the importance of accounting for land use trade-offs. However, sustainable food system transformations substantially recover this mitigation potential, increasing afforestation-based carbon sequestration to 5.01 GtCO2 yr−1 by 2100. Approximately 90% of this potential can be achieved at a cost below 50 USD tCO2−1. Our study emphasizes the need for integrated policies to balance climate mitigation with environmental conservation.