Evolution and Elasticity of Agricultural Carbon Balance in Beijing, Tianjin, and Hebei

Regional agricultural carbon balance studies are crucial for promoting coordinated development and achieving carbon neutrality. This research quantifies agricultural carbon emissions and sinks across 190 counties in the Beijing–Tianjin–Hebei (BTH) region from 2013 to 2022. The methodology involved the carbon emission factor approach and crop productivity models to assess the agricultural carbon balance. Furthermore, this study employed the carbon load model and the carbon output technical elasticity model to analyze the per-unit contribution of agricultural products and the carbon implications of augmented agricultural output. The findings reveal the following: (1) Total agricultural carbon emissions followed a fluctuating, inverted “U”-shaped trajectory, peaking in 2015. Emission reductions were primarily driven by decreases in agricultural energy consumption and land utilization, followed by crop cultivation. Conversely, agricultural net carbon sequestration and the carbon offset ratio show a fluctuating upward trend. (2) The agricultural carbon balance exhibits a distinct north–south differentiation. There has been a year-on-year reduction in carbon deficit counties, while the spatial aggregation of the carbon balance has become increasingly pronounced over time. (3) The marginal contribution of the agricultural carbon balance across the five primary agricultural zones positively correlates with the scale of agriculture and the prevailing crop cultivation regimes. Specifically, the Central Hebei Plain agricultural zone demonstrated the highest contribution, while the Daming agricultural zone exhibited the lowest. (4) Driven by the synergistic effect of internal and external factors, the BTH region has optimized its production elements. This has led to an elevated agricultural carbon balance and reduced inter-regional disparities. The region’s agricultural carbon balance demonstrates a favorable trajectory, suggesting sustainability under a low-carbon development paradigm. This study offers sustainability recommendations based on four pillars: establishing rigid production systems, enhancing compensation and trading mechanisms, optimizing industrial structures and integration strategies, and reinforcing regional coordination and incentive frameworks.