Biform differential game approach to dynamic carbon reduction cooperation in transnational supply chains under CBAM
研究了碳边境调节机制下跨国供应链中分销商与制造商在碳减排上的合作与非合作模式，发现合作模式下定价和减排决策动态演化并趋于稳定，且分销商利润随碳价上升而增加，而非合作模式下利润呈倒U型。
The Carbon Border Adjustment Mechanism (CBAM) is a border tax implemented by highly carbon-regulation countries (HCRC) on imports from less carbon-regulation countries (LCRC). To analyse carbon reduction cooperation in transnational supply chains under CBAM, this study develops a biform differential game model involving a distributor in HCRC and two manufacturers (from HCRC and LCRC) supplying homogeneous products. Within this framework, supply chain members cooperate in carbon reduction while independently setting the wholesale prices or retail prices. The findings reveal a key distinction between cooperative and non-cooperative modes: under non-cooperation, pricing and emission reduction decisions remain static, whereas under cooperation, they dynamically evolve and gradually stabilise. Moreover, as the CBAM price increases, distributors in the cooperative model increase the LCRC product sales but reduce them in the non-cooperative setting. Consequently, under cooperation, the distributor’s profit increases with CBAM prices, while under non-cooperation, the profit follows an inverse U-shaped pattern. Finally, the cooperative mechanism enhances sales, emission reductions, and both LCRC and HCRC manufacturers’ profits compared to the non-cooperative model. However, the distributor achieves higher profits only when CBAM prices are sufficiently high, and thus should adopt the cooperative strategy under the same condition.