Impact of water utilization changes on the water-land-energy-carbon nexus in watersheds: A case study of Yellow River Basin, China

Promoting the transformation of water, land, energy and carbon management to "multi-resource" synergy contributes to thoroughly assess the carbon reduction potential of regional human behavior in response to climate change from the angle of the source of production and the coupling development of resources, which is significant in promoting resource conservation and improving production efficiency. This study conducts a conceptual framework to evaluate the impact of water utilization changes on the water-land-energy-carbon (WLEC) nexus in the Yellow River Basin (YRB), and quantitatively discusses the complex interactions between water utilization changes and the total WLEC system and subsystems by applying the coupling coordination degree. Results present that: (1) the overall difference in the water utilization quantity of the YRB is expanding, and the water utilization types and efficiency show significant heterogeneity of flow segments. (2) Incorporating water into the land-energy-carbon system leads to an increase in the overall coupling and coupling coordination values in the YRB, and different reaches show different growth heterogeneity. (3) The coordination levels of the two-factor system consisting of the water and land-energy-carbon subsystems will be superimposed or canceled out, thus impacting the coupling coordination of the WLEC nexus. This study helps to further clarify the impact of water utilization changes on the land-energy-carbon system and its internal subsystems, and the combination of the WLEC nexus can provide references for governments to establish regional synergistic development models of water-land-energy resources and reduce carbon emission with their resource advantages.