Food security impact gauged by carbon accounting of food life cycle

Food security is closely related to society and national economy. Carbon accounting based on food life cycle could identify activities with high carbon emissions, conducive to ensuring food security under the goal of carbon neutrality. The life cycle of grain under the change of energy policy includes farmland planting, ethanol preparation and ethanol by-product resource utilization, and manure-return to the field. CH₄ emission is the main source of direct carbon emission, and indirect carbon emission is mainly due to application of chemical fertilizer, especially nitrogen fertilizer. Land use change (due to urban expansion, conversion of farmland to forests and changes in energy policies) is another factor affecting food security. Future nitrogen use efficiency should be improved, organic fertilizer should be applied, urban construction should be rationally planned, carbon accounting system should be established for coordinated development of grain and forest land, and non-grain fuel ethanol should be developed. Impact of resource utilization of food crop by-products on food security was analyzed, food by-product production of feed was found to reduce feed industry demand for food, manure-return to the -field could reduce the use of industrial fertilizers and improve soil quality. Impact of by-product feed production and manure-return on carbon emissions were not studied．In the future, carbon accounting could be combined with food life cycle to help policy makers to find a low-carbon and high-yield food security model in the life cycle to ensure a stable pattern of food security.