Carbon footprint of global rice production and consumption

Rice paddies are not only sources of staple food for half of the global population but also account for nearly half of the anthropogenic greenhouse gas emissions (GHGs) of croplands. Carbon footprint (CF) is a key tool for identifying and weighting sources of the GHGs along the food supply chain, promoting the efforts to curb these emissions within the targets of the climatic change protocol of the Paris Agreement. We introduced a comprehensive global quantification of rice CF, including direct and indirect emissions and sinks of the GHGs of inputs production, packaging, transportation, and application, soil and plant systems, farm operations, and uses of the produced biomass until the end of life. Globally, the rice CF was 2430 kg CO(2)eq. Mg-1 grain in 2020, of which 46% and 42% were sourced from the Gate and Grave stages, respectively, after excluding 3265 kg CO(2)eq. Mg-1 grain, that is the assimilated C in plant biomass. Net GHGs emissions of soil, biomass mulching and burning, and farm operations accounted for 20, 17, and 63%, respectively of the Gate stage CF. Meanwhile, food consumption contributed to the Grave stage CF by 92%. The rice CF ranged between 14 and 4854 kg CO(2)eq. Mg-1 grain among countries, wherein, for example, the rice CF values in Indonesia, India, Vietnam, and Russia represented 9, 50, 97, and 122% of the global average. Southeast, South, and East Asia were the major contributors (35, 34 and 18%, respectively) to the atmospheric CO2 load (2.4 Pg CO(2)eq.) of global rice production and consumption. This CO2 load will increase to 3.1 Pg CO(2)eq. in 2100, driven by a 32% growth in rice consumption. Here, we suggested an optimistic strategy (green energy use, hybridization, improving use efficiency of the inputs, and reducing food losses) to reduce the CO2 load by 60%.