Global Potential of Soil Carbon Sequestration to Mitigate the Greenhouse Effect

TLDR

Atmospheric CO₂ has risen from 280 ppmv in 1750 to 367 ppmv in 1999, largely due to fossil‑fuel emissions (~270 Pg C) and land‑use change, of which ~78 Pg C originates from depletion of soil organic carbon, with most agricultural soils having lost 50–70 % of their original SOC pool. The study proposes that restoring degraded soils, converting marginal lands to suitable uses, and adopting recommended management practices can reverse SOC loss and promote sequestration. SOC sequestration can be achieved through conservation tillage, manure and compost application, integrated nutrient management, precision farming, shifting from monoculture to diverse cropping systems, meadow rotations, winter cover crops, and establishing perennial vegetation on contours and steep slopes. Globally, SOC sequestration could absorb 0.6–1.2 Pg C yr⁻¹ for about 50 years, totaling 30–60 Pg C, offering a cost‑effective climate‑mitigation strategy in the first 2–3 decades while improving soil quality, productivity, and environmental quality.

Abstract

Abstract An increase in atmospheric concentration of CO2 from 280 ppmv in 1750 to 367 ppmv in 1999 is attributed to emissions from fossil fuel combustion estimated at 270±30 Pg C and land use change at 136±55 Pg. Of the emissions from land use change, 78±12 Pg is estimated from depletion of soil organic carbon (SOC) pool. Most agricultural soils have lost 50 to 70% of their original SOC pool, and the depletion is exacerbated by further soil degradation and desertification. The restoration of degraded soils, conversion of agriculturally marginal lands to appropriate land use, and the adoption of recommended management practices on agricultural soils can reverse degradative trends and lead to SOC sequestration. Technological options for SOC sequestration on agricultural soils include adoption of conservation tillage, use of manures, and compost as per integrated nutrient management and precision farming strategies, conversion of monoculture to complex diverse cropping systems, meadow-based rotations and winter cover crops, and establishing perennial vegetation on contours and steep slopes. The global potential of SOC sequestration and restoration of degraded/desertified soils is estimated at 0.6 to 1.2 Pg C/y for about 50 years with a cumulative sink capacity of 30 to 60 Pg. The SOC sequestration is a costeffective strategy of mitigating the climate change during the first 2 to 3 decades of the 21st century. While improving soil quality, biomass productivity and enhanced environment quality, the strategy of SOC sequestration also buys us time during which the non-carbon fuel alternatives can take effect.