Soil Carbon Sequestration Impacts on Global Climate Change and Food Security

TLDR

The world's agricultural and degraded soils store 50–66 % of the historic 42–78 GtC loss, but the rate of soil organic carbon sequestration depends on texture, structure, climate, farming system, and management. Strategies to boost the soil carbon pool include soil restoration, woodland regeneration, no‑till, cover crops, nutrient management, manuring, sludge application, improved grazing, water conservation, efficient irrigation, agroforestry, and energy crop cultivation on spare lands. Increasing the soil carbon pool by 1 t ha⁻¹ on degraded cropland can raise wheat yields by 20–40 kg ha⁻¹, maize by 10–20 kg ha⁻¹, cowpeas by 0.5–1 kg ha⁻¹, and offset 0.4–1.2 GtC yr⁻¹ of fossil‑fuel emissions (5–15 % of global emissions).

Abstract

The carbon sink capacity of the world's agricultural and degraded soils is 50 to 66% of the historic carbon loss of 42 to 78 gigatons of carbon. The rate of soil organic carbon sequestration with adoption of recommended technologies depends on soil texture and structure, rainfall, temperature, farming system, and soil management. Strategies to increase the soil carbon pool include soil restoration and woodland regeneration, no-till farming, cover crops, nutrient management, manuring and sludge application, improved grazing, water conservation and harvesting, efficient irrigation, agroforestry practices, and growing energy crops on spare lands. An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 20 to 40 kilograms per hectare (kg/ha) for wheat, 10 to 20 kg/ha for maize, and 0.5 to 1 kg/ha for cowpeas. As well as enhancing food security, carbon sequestration has the potential to offset fossil fuel emissions by 0.4 to 1.2 gigatons of carbon per year, or 5 to 15% of the global fossil-fuel emissions.