Governing Workplace Heat Risk Under Climate Change: A Tripartite Evolutionary Game of Regulators, Employers, and Workers

Workplace heat exposure under climate change is not only a physical hazard but also a recurrent governance problem involving regulators, employers, and workers. This paper develops a tripartite evolutionary game to examine how workplace heat-risk governance evolves through the interaction of strict regulation, employer prevention investment, and worker symptom reporting. Normal-form Nash and Stackelberg benchmarks are used to clarify the static and sequential counterparts of the evolutionary stability conditions. Heat-risk intensity is introduced as an environmental state that affects accident probability, expected losses, governance costs, and institutional benefits. The model identifies a heat-dependent cooperative stability region: full cooperation is locally stable only when digital monitoring, enforcement incentives, employer investment support, and worker reporting protection jointly satisfy threshold conditions. Extended payoff specifications allow monitoring and regulatory strictness to directly affect worker reporting incentives and link government payoffs to accident-risk reduction. The results show that monitoring and reporting protection may be partially substitutable in the worker-reporting channel but remain non-equivalent at the system level. Long-horizon, shock-recovery, and industry-specific diagnostics further show that isolated instruments often generate partial-governance regimes rather than system-wide cooperation. The findings frame workplace heat adaptation as a complex adaptive governance problem requiring coordinated technological visibility, credible enforcement, employer incentives, and protected worker reporting.