Evaluating Urban Carbon Neutrality Pathways and Co-benefits through an Integrated Downscaling Framework: A Case Study of the Beijing–Tianjin–Hebei Region, China

To address the dual challenges of climate change and air pollution, an urban-scale decision-making framework is required in China to quantify energy–environment–health co-benefits, thereby addressing the limitations of existing macro-level research. This study proposes a novel analytical framework integrating scenario prediction, dynamic downscaling, pathway optimization, and benefit evaluation. The framework combines the provincial-level Global Change Analysis Model (GCAM-China) with a municipal-level dynamic downscaling model, a high-resolution emission inventory (Gridemis), the Scenario Model Intercomparison Project (ScenarioMIP), and an air quality and health assessment model. This approach effectively translates national climate goals into heterogeneous, sector-specific, municipal-scale emission pathways. It quantifies energy structure transitions, pollutant mitigation, and health co-benefits under various policy mixes while also considering future climate-related risks. Applied to the Beijing–Tianjin–Hebei region, the results show that synergistic efforts for carbon neutrality and stringent air quality policies will drive the regional energy system from coal dominance to a diversified, cleaner structure. By 2060, this optimized pathway could reduce major air pollutant emissions by 30–88%, promote a more equitable distribution of environmental and health benefits, and significantly lower premature mortality risks. This study provides a practical tool for energy and environmental policy, offering broad applicability for other regions.