From Trade Catch-Up to Low-Carbon Upgrading: Provincial Regime Dynamics and FTZ Effects in China

Amid accelerating globalization, climate change, and the transition toward sustainable development, reconciling international trade expansion with low-carbon transformation has become a central challenge for regional economies. This study examines the coordinated evolution of provincial trade and low-carbon development in China and identifies the conditions and policy factors associated with regime upgrading. Using panel data for 31 Chinese provinces from 2000 to 2022, we construct trade and low-carbon development indices and identify their coordination patterns and latent regimes. Machine learning with SHAP is then used to predict regime upgrading, while double machine learning estimates the effects of free trade zone exposure. The coordination degree increased from 0.560 to 0.736, mainly because the initially lagging trade subsystem caught up with low-carbon development. Four regimes were identified, with 94.3% annual persistence, indicating strong path dependence. FTZ exposure significantly improved trade development and coordination but produced no significant short-run low-carbon effect. Policies should integrate trade facilitation with industrial upgrading, clean-energy transition, and stronger environmental regulation.