Effective reduction of agricultural carbon emissions via land-use- structure adjustment: A case study of Sichuan Province, Southwest China

China is currently the largest emitter of carbon dioxide globally. The nation, vulnerable to the imminent challenges of climate change and greenhouse gas emissions, is determined to reduce emissions. Thus, by adopting a systems-theory approach, this study is aimed at examining how the agricultural lands, output values, production activities, and populations, as well as the economic factors, influence carbon emissions in Sichuan Province. To offer insights into the long-term agricultural carbon emission (ACE) trajectories, a system dynamics model is used to predict the emission trends from 2023 to 2040. The findings indicate the following: ① policy regulation exerts influence on the ACE in the province. As per the simulation results, regulating the gross domestic product growth of the primary industry at 2.5%, 5%, and 10% will only increase the carbon emissions by 0.24%, 0.25%, and 0.53%, respectively, by 2040, indicating that effective policy regulations can decouple economic growth from substantial increases in emissions, thereby underscoring their pivotal role in emission control. ② Regulating the agricultural-economy growth rate and policies can effectively reduce ACEs in the province. ③ While single policies exert limited influence, combining multiple measures significantly boosts carbon reduction. For example, comprehensive strategies, including reduced pesticide use and marginal farmland conversion, can lower agricultural land carbon emissions by 3.48%, 5.30%, and 7.47% (by 2035) and 1.67%, 2.76%, and 3.65% (by 2040). Overall, these results emphasize the effectiveness of coordinated policies, alongside market control and land-use adjustments, in advancing low-carbon agricultural development.