Water–energy–carbon nexus of China’s Yellow River water allocation schemes

• The impact of transboundary river water allocation on carbon emissions was explored. • A transboundary water-energy-carbon nexus accounting framework was developed. • Carbon emissions from transboundary river water allocation of different scenarios were assessed. • The pathway of water allocation to achieve carbon neutrality in Yellow River in 2060 were investigated. Water allocation in rivers that cross borders is of critical concern in the field of water resource management. However, the interactions between water allocation, energy consumption, and carbon emissions have been traditionally overlooked in the design of water allocation strategies. In this paper, a GIS-based transboundary water–energy–carbon nexus accounting framework is developed to assess the carbon emissions associated with water extraction in transboundary rivers. Taking the Yellow River in China as a case study, the carbon emissions during 1998–2020 associated with three water allocation schemes are quantified. Then, future emissions for 2060 are projected using 21 different scenarios incorporating 3 emission-reduction strategies: thermal power efficiency improvements, clean energy utilization, and carbon capture and storage coupled with three water allocation schemes. The findings indicate substantial carbon emissions (2.41 × 10 8 t) associated with water extraction from transboundary rivers during 1998–2020, which could be reduced by 90 % through improved energy system and water allocation schemes. By building a new framework, this study promotes quantitative coordination and allocation of transboundary river water resources, energy usage, and carbon emissions, thereby providing insights for transboundary river management.