Title: Holistic governance strategy to reduce carbon intensity

The "dual carbon" goals of carbon peaking and carbon neutrality constitute an important strategic decision for China in the new era. For the purpose of elaborating the internal correlation between the BTH coordinated development strategy and carbon dioxide intensity (carbon intensity), this study uses the synthetic control method (SCM) to test the effect of BTH coordinated development strategy on reducing carbon intensity. The SCM is combined with the improved logarithmic mean Divisia index method to analyze the mechanisms promoting changes in carbon intensity. The study found that the BTH coordinated development strategy has had a positive impact on carbon intensity reduction, demonstrating that the policy effect has intensified, with carbon intensity dropping by 15%–20%. It is further determined that the strategy primarily uses two main paths of industrial energy intensity and energy structure to reduce carbon intensity, and its contribution to the overall policy effect exceeds 64%. Notably, the reduction of carbon intensity in Tianjin primarily depended on energy intensity, and the energy structure generated a negative hindrance during the study period. The research results, particularly the demonstrated differentiation in regional characteristics, provide decision support for the BTH holistic governance strategy for carbon peaking and carbon neutrality in China.