Bargaining-Game and Distribution Mechanism Design for GHG Carbon Pricing Under the IMO Net-Zero Framework

Under the IMO net-zero framework, a GHG carbon-pricing mechanism must not only generate an effective price signal for emission reduction, but also address the fair distribution of carbon revenues among different types of member states. In view of the differences between developing and developed countries in transition needs, responsibility attribution, and policy affordability, this paper develops a multilateral bargaining model that incorporates a responsibility–need reference point, loss aversion, horizontal fairness preferences, and a voting threshold, and analyzes the equilibrium formation mechanism for the distribution of carbon-pricing revenues. Theoretical derivation shows that a higher responsibility–need weight raises the fairness reference point of developing countries and increases their minimum acceptable allocation requirement; loss aversion operates through a rejection-threat channel by shrinking the acceptable set of proposals below the reference point; and horizontal fairness preferences compress the relative deviation gap between the two types of countries and may trigger a transformation of the support structure once certain thresholds are reached. The simulation results show that, in the baseline L-proposer case, developing countries receive 105.48 out of the normalized revenue R=120, while developed countries receive 14.52. Under the stress scenario with q=121>NL=120, the mechanism requires cross-type support and yields group-level allocations of 106.56 and 13.44, respectively. At the same time, horizontal fairness preferences and voting rules jointly weaken the proposer’s ability to obtain additional gains through agenda-setting power. The study indicates that the IMO carbon-revenue distribution mechanism should strengthen responsibility–need orientation and cross-type support constraints while maintaining a unified carbon price signal, so as to improve the fairness, acceptability, and institutional stability of the carbon-pricing mechanism.