Crop-Based Greenhouse Gas Emission Patterns: Implications for Climate Change and Sustainable Mitigation

Greenhouse gases (GHGs) are natural constituents of the atmosphere and contribute to maintaining the Earth’s temperature at levels required for life. The major GHGs discussed in this review are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and chlorofluorocarbons. However, rapid industrialisation, fossil fuel combustion, land-use change and intensified agricultural activities have increased their atmospheric concentrations, resulting in an enhanced greenhouse effect and global warming. This review examines greenhouse gas emission patterns associated with major agricultural crops, evaluates their implications for climate change and outlines sustainable crop management and climate-smart agricultural practices that can reduce emissions while supporting food security and environmental sustainability. Current global net anthropogenic GHG emissions are about 12% higher than in 2010 and nearly 54% higher than in 1990, while atmospheric concentrations of CO₂, CH₄ and N₂O have increased by approximately 35%, 148% and 18%, respectively, compared with the pre-industrial era. Agriculture contributes substantially to greenhouse gas emissions, particularly methane and nitrous oxide, with crop-specific emissions varying according to crop type, irrigation regime, fertiliser use, residue management, soil condition and field practices. Rice-based systems are associated mainly with methane emissions under flooded and anaerobic conditions, whereas intensive cereal systems such as wheat and maize contribute notably to nitrous oxide emissions through nitrogen fertiliser use. In contrast, millets, pulses and diversified cropping systems generally show lower emission potential and greater resilience under variable climatic conditions. Improper residue disposal and manure management further increase emissions. The review emphasises that crop diversification, alternate wetting and drying, conservation tillage, residue recycling, efficient nutrient management, water-saving technologies and inclusion of legumes can support emission reduction and more sustainable agricultural production systems.