Restoring grasslands for a cooler planet: The role of soil carbon in climate solutions

Abstract

Grasslands, which span a significant portion of the earth’s surface, are vital for climate change mitigation due to their capacity to sequester atmospheric CO₂, with up to 20% of terrestrial carbon stored as soil organic carbon (SOC) in their root zones. However, anthropogenic pressures can reverse this role, turning grasslands into carbon sources, with CO₂ emissions closely linked to soil moisture, temperature, and organic content. Land degradation exacerbates this by depleting SOC stocks and degrading soil function, making sustainable land management critical for maintaining productivity, food security, and environmental health. Enhancing SOC through plants with high photosynthetic efficiency, deep roots, and high biomass output particularly in tropical pastures offers promising avenues for land rehabilitation and biomass energy use. These pastures, with their ecological diversity and deep-root systems, are well-suited for storing carbon in subsoil horizons and improving landscape stability. Globally, grassland SOC sequestration potentials are estimated at 2.3-7.3 billion tons CO₂ annually through biodiversity restoration, 148-699 megatons via improved grazing management, and 147 megatons through the use of legumes, positioning these strategies as low-cost, high-yield climate solutions (Bai and Cortrufo, 2022).