Historical carbon emissions and future mitigation potentials from staple food cropping systems in China.

China's demand for staple food continues to grow, and securing the supply of staple food for 1.4 billion people is of great significance for China's and the world's food security. The trend and potential of carbon emissions from staple food cultivation will profoundly affect the sustainability of this system. Using comprehensive data based on geographic information systems (GIS) and statistical yearbooks, we constructed a carbon emission accounting model for China's staple food cropping system, accounted for the historical trend of its emissions, and analyzed the trend of staple food cropping-carbon emission in different regions with the help of a decoupling model. We used Scenario planning (SP) to create five future scenarios, namely, baseline, technological advances, self-sufficient, reducing food losses, and synthesized, to predict the future emission potential of the system. The results show that carbon emissions from China's staple food cropping system peaked around 2015-2016, and have now declined by 18 Tg from the peak, with field management activities accounting for the highest proportion of emissions, but all subsystems show a declining trend, and a weak decoupling of staple grain production-carbon emissions has been achieved in most regions, with carbon sinks playing a key role in the staple grain cropping system. The results of the scenario simulations show that carbon emissions from China's staple food cropping system will continue to increase under the baseline scenario, the technological advances scenario can reduce carbon emissions by about 20 %, and the emission reduction potential reaches about 25 % under the synthesized scenario. The results point to the importance of reducing food losses in reducing carbon emissions, and the trend of carbon emissions can be effectively curbed under this scenario without the imposition of other measures. If the current production pattern is continued and expanded, the carbon sink of the system will offset the new increase in carbon emissions, which provides new evidence for the expansion of production. Reviewing the shortcomings in the development of staple food cropping systems, accurately assessing the current state of development in different regions, and emphasizing the combined effects of key measures in future development are critical to achieving China's own sustainable agricultural development and food security, and provide empirical evidence for achieving the SDGs' Zero Hunger and Climate Action goals.