Voluntary or mandatory? Convergence and coexistence of “dual carbon” markets: A system dynamics analysis based on multi-agent evolutionary games

In the context of intensifying global climate change and the deepening advancement of "dual carbon" goals, exploring the synergistic mechanisms between voluntary and mandatory carbon markets has become a critical pathway for achieving systemic emission reductions in China. To realize effective integration and dynamic coexistence of these two markets, this study employs evolutionary game theory and system dynamics to construct a tripartite game model involving the government, traditional and renewable energy enterprises. This research demonstrates that: (a) There exists a synergistic threshold effect between carbon prices and subsidies. A critical carbon price triggers a significant increase in the proportion of traditional energy enterprises engaging in active emission reduction, while subsidies exceeding a certain threshold can result in excessive regulatory costs. (b) Public evaluations significantly drive the strategic evolution of market participants. Public willingness-to-lose and government reputation loss can accelerate corporate emission reduction efforts and enhance the intensity of governmental regulatory actions. (c) High carbon prices combined with tiered subsidy mechanisms can shorten the technological transition periods for traditional energy enterprises. The development of proactive emission reduction processes requires supportive government subsidies to mitigate risks. Based on these findings, the work proposes specific policy recommendations and stage-wise implementation pathways. • It uses evolutionary game theory to model government and energy firms, revealing carbon market synergy and policy effects. • It examines bounded rationality, social evaluation, and loss willingness in agent decisions and evolutionary paths. • It proposes government policies for traditional energy sector to foster innovation and emission reduction. • It analyzes the synergistic and threshold effects of policy instruments within the carbon market evolution.