<p>Growing public environmental concern (PEC) has increasingly shaped the governance of agricultural sustainability, yet its role in mitigating agricultural carbon emissions (ACE) remains insufficiently understood. This study contributes to the literature by incorporating informal environmental regulation into the analysis of ACE and developing an integrated PEC–GTI–ACE analytical framework. Using panel data from 30 Chinese provinces over 2011–2022, we examine how PEC affects agricultural carbon emission intensity, as well as the moderating and nonlinear roles of green technological innovation (GTI), employing two-way fixed effects, moderation, and threshold regression models. The empirical results show that higher levels of public environmental concern significantly reduce agricultural carbon emission intensity, with a stable and robust coefficient of approximately − 0.060 across alternative specifications. GTI plays a reinforcing role in this process. The interaction between public concern and green innovation is significantly negative, with an estimated coefficient of − 0.014, indicating that advances in green innovation amplify the carbon mitigation effect of PEC. Further analysis reveals a nonlinear threshold effect in GTI, with a single threshold estimated at 0.337. Once this threshold is exceeded, the suppressive impact of PEC on ACE becomes markedly stronger. Subregional analyses indicate that the threshold effects observed in the eastern and central regions are broadly consistent with the national pattern, while the western region exhibits pronounced heterogeneity. By uncovering both the complementary and threshold-based mechanisms between public environmental awareness and green technological innovation, this study provides new evidence on how behavioral and technological factors jointly shape agricultural carbon reduction. Overall, the findings suggest that PEC and GTI act as complementary forces in mitigating ACE.</p>