Integrated Assessment of Anthropogenic Carbon, Nitrogen, and Phosphorus Inputs: A Panjin City Case Study

Energy consumption and environmental pollution pose significant challenges to sustainable development. This study develops a comprehensive coupled framework model that advances the quantitative integration of carbon (C), nitrogen (N), and phosphorus (P) cycles driven by multiple anthropogenic pollution sources. This paper used Panjin city as a case study to analyze the dynamic changes and interconnections among C, N, and P. Results indicated that net anthropogenic carbon inputs (NAIC) increased by 33% from 2016–2020, while net anthropogenic nitrogen inputs (NAIN) and net anthropogenic phosphorus inputs (NAIP) decreased by 14% and 28%, respectively. The primary driver of NAIC was energy consumption, while wetlands were the dominant carbon sequestration sink. Agricultural production was identified as the primary source of NAIN and NAIP, and approximately 4.5% of NAIN and 2.9% of NAIP were discharged into receiving water bodies. We demonstrate that human activities and natural processes exhibit dual attributes, producing positive and negative environmental effects. The increase in carbon emissions drives economic growth and industrial restructuring; however, the enhanced economic capacity also strengthens the ability to mitigate pollution through environmental protection measures. Similarly, natural ecosystems, including forests and grasslands, contribute to carbon sequestration and the release of non-point source pollution. The comprehensive environmental impact assessment of C, N, and P revealed that the comprehensive environmental index for Panjin city exhibited an improved trend. The factors of energy structure, energy efficiency, and economic scale promoted NAIC growth, with the economic scale factor alone accounting for 93% of the total increment. Environmental efficiency factor and population size factor were the primary drivers in reducing NAIN and NAIP discharges into the receiving water bodies. We propose a novel management model, ecological restoration, clean energy utilization, resource recycling, and pollution source reduction to achieve systemic governance of C, N, and P inputs.