Coordinated emission reduction strategy of water pollution and carbon emissions in the South-to-North Water Diversion Project based on a differential game model

This study investigates the green development of the South-to-North Water Diversion Project (SNWDP) by exploring the synergistic reduction of water pollution and carbon emissions. Firstly, a differential game model is constructed to reduce pollution and carbon in the water supply chain. Secondly, the emission reduction strategies of water source and receiving areas under centralized and decentralized decision models are compared and analyzed and a cost-sharing contract is designed to coordinate the supply chain. Finally, numerical analysis is used to compare and analyze the important parameters to draw conclusions. The results show that: (1) Collaboration between water source and receiving areas influences emission reduction efforts, with the highest achieved under the centralized model. (2) The cost-sharing contract improves efforts and addresses ‘free-riding’ in the decentralized model. (3) The SNWDP can achieve a win-win situation in terms of both environmental and economic benefits by promoting the synergy of pollution reduction and carbon reduction.