Can dual-pilot policy of innovative city and carbon trading promote carbon productivity? Empirical evidence from dual-pilot city in China

China is committed to reducing carbon emissions and advancing sustainable development. The carbon emissions trading pilot and innovative city pilot programs serve as crucial policy instruments for achieving carbon neutrality and high-quality economic growth. Carbon productivity, a comprehensive metric that balances emission reduction and economic performance, provides a rational indicator for assessing these dual objectives. Investigating the synergistic effects of these dual-pilot policies on carbon productivity holds significant importance. This study evaluates the impact and mechanisms of the “dual-pilot policy” (integrating carbon trading and innovative city policies) on urban carbon productivity. It is evident from the findings that the dual-pilot policy substantially enhances carbon productivity (0.365), fostering regional green economic development. Heterogeneity analysis indicates that the policy's impact exhibits development convergence characteristics. In exploring policy synergy, this study demonstrates that dual-pilot implementation generates unique contributions: for cities already participating in a single pilot, adopting the dual-pilot policy leads to an additional 14.1 % increase in carbon productivity compared to their baseline levels. Furthermore, the policy sequencing of “innovation-first followed by carbon trading” yields superior outcomes (0.239). By innovatively exploring the joint outcomes associated with dual-pilot policy synergy on carbon productivity. This research beyond advancing scholarly discourse on decarbonization, the analysis yields operational frameworks to optimize policy synergy effects.