7. Role of Biochar in Carbon Sequestration and Greenhouse Gas Mitigation

Global warming and associated climate change are becoming a threat to almost all the ecosystems on the earth. According to the intergovernmental panel on climate change (IPCC) special report 2019, the global mean surface (land and ocean) temperature has been increased by 0.87 °C while mean of land surface air temperature has increased by 1.53 °C since 1850–2015. Climate change is affecting food security and human life due to warming, changing precipitation patterns, and the greater frequency of some extreme events. The main cause of global warming is the continuous increase in the atmospheric concentration of greenhouse gases (GHGs) like CO₂, CH₄, N₂O and fluorinated gases due to several anthropogenic activities. Therefore, reducing the increasing concentration of GHG is necessary to slow down global warming and climate change. Among several options of greenhouse mitigation, application of biochar into the soil is gaining popularity due to several advantages over other options. Biochar is a highly stable form of carbon derived from pyrolysis of biomass at relatively low temperatures. Application of biochar into the soil has been reported to provide multiple benefits like increase in crop yield, nutrient and water use efficiency and several environmental benefits. Recalcitrant nature, relatively higher carbon content and easily available feedstock make biochar a highly sustainable and quick option for carbon sequestration into the soil. Biochar application into the soil not only helps in carbon sequestration but also provides a better option for managing agricultural residues. The application of biochar has also reported for reducing a considerable amount of methane and nitrous oxide emission from the agricultural field due to its priming effect on the soil. Biochar yield, physical properties, and carbon content varies with the type of feedstock and pyrolysis condition. Therefore, the rate of carbon sequestration and mitigation of greenhouse gas is also highly variable, however, the biochar application ultimately leads to a positive contribution towards climate change mitigation. However, most of the reported benefits are confined to laboratory and field trial at institute level, widespread adoption of biochar on farmer’s field is still lacking. In the present chapter, all the aspects of biochar towards carbon sequestration and greenhouse mitigation have been well discussed.