Inter-provincial water-energy-carbon transfer and its efficiency in China: the perspective of land use

BACKGROUND: Revealing inter-regional water-energy-carbon transfer driven by land use has great significance for realizing multiple objectives of resource collaborative optimization and carbon mitigation, yet land-use WEC accounting at the provincial scale and the efficiency of inter-regional WEC transfer driven by embodied land flow remain insufficiently explored in China. Accordingly, a theoretical framework for water-energy-carbon accounting and inter-regional transfer based on land use was established. Then the water and energy use and carbon emissions of cropland, forest land, grassland, water area, and construction land in 30 Chinese provinces were estimated and their spatial-temporal patterns were analyzed. The efficiency and spatial characteristics of inter-provincial water-energy-carbon transfer driven by embodied land flow were discussed. RESULTS: The results showed that the land-use water consumption was relatively stable from 2005 to 2020, while land-use energy consumption and carbon emissions exhibited an increasing trend. Embodied land mainly flowed from underdeveloped areas to developed areas, and there was regional variability in the related water-energy-carbon transfer. The energy-carbon transfer patterns driven by embodied land flow were similar. Embodied land consumption was concentrated in cropland, forest land, and grassland. Water consumption driven by embodied land flow was primarily concentrated in cropland. Energy consumption and carbon emissions driven by embodied land flow were mainly concentrated in construction land. Generally, the embodied land flow-related water-energy-carbon transfer efficiency has improved, with the proportion of efficient transfer increasing by 2.03%, 2.08%, and 2.82%, respectively. Water transfer between different land use types was more efficient than energy-carbon transfer, and water-energy-carbon transfer associated with construction land was inefficient. CONCLUSIONS: Water-energy-carbon transfer driven by embodied land flow could alleviate resource and environmental pressures, while its efficiency could still be enhanced. Therefore, in the future, land resource allocation should be optimized based on regional coordination and integrated water-energy-carbon management to enhance the efficiency of cross-regional water-energy-carbon transfer, thereby achieving efficient resource utilization and environmental sustainability. Overall, this study provides quantitative evidence for the resource and environmental impacts of cross-regional land resource allocation and offers new insights for synergistic resource optimization from a remote coupling perspective.