Sequestering Carbon in Agriculture: Innovations for Climate Mitigation
Abstract
Carbon sequestration plays a crucial role in addressing climate change by lowering the concentration of carbon dioxide (CO₂) in the atmosphere. With the rapid increase in greenhouse gas (GHG) emissions, the Earth’sclimate is undergoing significant transformations, making it essential to adopt strategies that counteract these emissions. Among various solutions, soil carbon sequestration stands out as an effective method, particularly because degraded and agricultural soils hold substantial capacity for storing additional carbon. Globally, soils are capable of storing nearly twice as much carbon as the atmosphere and terrestrial vegetation combined. The amount of carbon held in soil is influenced by both climatic conditions and soil characteristics. Agricultural practices—including land-use changes, crop residue handling and soil management— playa major role in determining soil carbon levels. Improving these practices not only enhances soil carbon stocks but also supports food security and promotes sustainable farming systems. The development of carbon sequestration technologies is increasingly important. Abiotic approaches such as CO₂ injection into oceans, geological formations, and mineral carbonation offer long-term storage solutions, while biotic approaches rely on natural processes and tend to be more affordable and faster to implement. Together, these methods complement each other and contribute to reducing the risks associated with climate change. Human activities, especially the burning of fossil fuels, have significantly increased atmospheric CO₂ concentrations, resulting in global warming and a range of environmental challenges. Therefore, it is essential to adopt strategies that both limit emissions and actively remove CO₂ from the atmosphere. This chapter provides an in-depth examination of carbon sequestration—its definition, processes, benefits, and challenges—along with its importance in mitigating climate change and enhancing our understanding of its overall potential.
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Introduction
Carbon is an essential component for maintaining soil biological processes, ecosystem productivity, soil biodiversity, and overall environmental quality (Gaikwad, 2021). Atmospheric carbon enters land-based ecosystems primarily through photosynthesis, while it returns to the atmosphere through various respiration processes (Gaikwad, 2021). Even slight imbalances between the amount of carbon captured from the atmosphere and the amount released back can produce noticeable shifts in climate patterns over decades. In recent years, the excessive emission of carbon has negatively affected air, water, soil, and human well-being (Gaikwad, 2021).
Since the late 19th century, global surface temperatures have increased by approximately 0.88°C, with 11 of the 12 warmest years occurring after 1995 (IPCC, 2007). Projections indicate that Earth’saverage temperature could rise by 1.5–5.8°C by the end of the 21st century (IPCC, 2001). The warming trend has accelerated since 1975, with an estimated increase of 0.158°C per decade. These temperature shifts have also contributed to major ecological changes (Greene & Pershing, 2007) and arise in both the frequency and severity of wildfires (Running, 2006; Westerling et al., 2006). Much of this climate change is attributed to greenhouse gas (GHG) emissions produced by human activities—including land-use conversion, deforestation, biomass burning, drainage of wetlands, soil disturbance, and the combustion of fossil fuels. Since the Industrial Revolution around 1850, concentrations of GHGs and their radiative forcing have steadily increased alongside human population growth. Carbon dioxide (CO₂) levels, for example, climbed from 280 ppmv in 1850 to 380 ppmv in 2005, and continue rising by roughly 1.7 ppmv (or 0.46%) each year (WMO, 2006; IPCC, 2007). Methane (CH₄) and nitrous oxide (N₂O) show similar long-term upward trends (IPCC, 2001, 2007; Prather et al., 2001; WMO, 2006). Altogether, the total radiative forcing resulting from all greenhouse gases since 1850 is estimated at 2.43 W m⁻² (IPCC, 2001, 2007). To mitigate climate change and reduce CO₂ emissions, several strategies have been proposed (Schrag,2007): 1) Lowering global energy demand, 2) Developing energy sources that are low-carbon or carbon-neutral, and 3) Utilizing both natural and technological methods to capture and store CO₂ from emission sources or directly from the atmosphere.
Between 1850 and 1998, fossil fuel use emitted an estimated 270 ± 30 Pg of carbon, while land-use change, deforestation, and soil cultivation released an additional 136 ± 30 Pg (IPCC, 2001). At present, fossil fuel combustion contributes about 7 Pg C per year (Pacala & Socolow, 2004), and land-use change contributes another 1.6 Pg C annually. Of the total anthropogenic emissions of roughly 8.6 Pg C each year, about 3.5 Pgaccumulates in the atmosphere, 2.3 Pg is absorbed by the oceans, and the remainder goes into an unidentified terrestrial sink—likely situated in the Northern Hemisphere (Tans et al., 1990; Fan et al., 1998).
The purpose of this chapter is to examine the processes and technological pathways for long-term CO₂–C sequestration in major global carbon reservoirs. While presenting abroad overview of CO₂ sequestration, particular attention is directed toward soil-based (terrestrial) carbon sequestration and its role in reducing the rate of atmospheric CO₂ accumulation.
Conclusion
Natural terrestrial and oceanic carbon sinks currently absorb roughly 60% of the 8.6 Pg C emitted annually. However, these sinks alone are insufficient to offset anticipated anthropogenic CO₂ emissions. Increasing the carbon storage capacity of managed ecosystems—such as forests, soils, and wetlands—requires careful land-use planning and the adoption of Resource Management Practices (RMPs). Effective biotic or terrestrial carbon sequestration depends on managing biological processes and understanding the interactions between carbon, water, and other nutrient cycles.
Abiotic sequestration techniques, including direct injection of CO₂ into oceans or geological formations and mineral carbonation to form stable carbonates, provide significant potential for long-term storage. While these engineering-based methods are underdevelopment and may become widely available by 2026, further research is needed to make them cost-efficient, minimize leakage risks, and reduce environmental impacts.
Human dimensions, such as policy frameworks, regulatory oversight, measurement, monitoring, carbon residence time, and carbon credit systems, are critical considerations for implementing both biotic and abiotic sequestration strategies. Alongside carbon sequestration, reducing emissions through carbon-neutral technologies is essential. This includes adopting energy-efficient production and consumption practices and exploring renewable fuels, such as bioethanol, biodiesel, methane from anaerobic digesters, and hydrogen derived from biomass.
Carbon sequestration offers multiple benefits: mitigating climate change, enhancing soil health to support plant growth, and improving food security. Environmental factors—such as temperature, precipitation, and elevated atmospheric CO₂—affect soil organic matter (SOM) decomposition, while soil texture significantly influences the accumulation of soil organic carbon (SOC). Agricultural practices impact SOC differently depending on soil characteristics, including physical and biological properties. Conservation tillage, combined with suitable crop rotations and the inclusion of legumes, can improve soil organic content and boost SOC storage.
Overall, carbon sequestration strategies contribute to sustainable agriculture by enhancing soil health, reducing pollutant loads, and lowering atmospheric CO₂ concentrations.
CONFLICT OF INTEREST The authors declare no conflict of interest.
