[Objective] Amid a complex and volatile international landscape, the global nickel supply chain is characterized by regionalization and fragmentation, posing severe challenges to the stability of nickel supply. Simulating the propagation of nickel supply risks along the industrial chain and trade network can provide a scientific foundation for enhancing the security and resilience of the global nickel supply chain. [Methods] This study utilized the 2023 global nickel trade data from the UN Comtrade Database to construct a multilayer complex network model of the global nickel industrial chain structure across upstream, midstream, and downstream segments. It simulated two scenarios—unilateral export reduction and bilateral trade friction—to identify high-risk nodes within the nickel trade network and analyze the mechanisms through which supply risks propagated along the industrial chain and trade network. [Results] (1) The global nickel supply network was highly vulnerable. Export reductions by resource-rich and major supplying countries or regions could lead to widespread supply shortages, with risks cascading across different tiers of the industrial chain. (2) Risk propagation speed exhibited nonlinear variations, and its pathways showed hierarchical heterogeneity. Upstream links were primarily influenced by geographic proximity, while midstream and downstream stages displayed complex cross-regional diffusion. (3) Due to substantial differences in positions within the industrial chain and resource reserves, China and North American countries demonstrated distinctly different resilience levels and risk transmission characteristics. Under supply-risk shocks, China simultaneously serves as both a recipient and an amplifier of risk, whereas North American countries generally demonstrate greater resilience. [Conclusion] Global nickel supply risks exhibit pronounced cross-tier transmission along the industrial chain, with key resource-producing countries or regions and hub nodes serving as critical points for the initiation and propagation of supply risks. Therefore, in addition to diversifying import sources and strengthening strategic reserves, China should accelerate the development of a coordinated cross-tier early-warning and regulatory mechanism for nickel supply risks.
[Objective] This study examines the effects of high-standard farmland construction on farm household income growth and income distribution, identifies the mechanisms underlying its distributional effects, and provides a basis for coordinating farm household income growth with income equity. [Methods] The analysis used 2024 survey data from 1166 farm households in Sichuan Province. This study employed the IV-Tobit model and the recentered influence function (RIF) regression method to evaluate the impact of high-standard farmland construction on farm household income and income distribution. [Results] (1) High-standard farmland construction significantly boosted farm household incomes, as evidenced by increases across multiple income sources, including agricultural operating income, property income, and transfer income. (2) Although overall income levels of farm households rose, this policy widened income disparities among farm households, with a stronger marginal income-increasing effect for high-income groups, exhibiting a “top-end pull-up” pattern. (3) Mechanism analysis revealed a clear scale-oriented effect of high-standard farmland construction. Large-scale farm households benefited more from income growth due to their resource advantages, and this divergence was particularly pronounced under centralized land transfer modes. In contrast, under self-organized land transfer modes, smallholders experienced greater income gains, thereby mitigating income disparities. [Conclusion] Overall, high-standard farmland construction enhances agricultural efficiency and increases farm household incomes. However, it also introduces new distributional challenges. Policy design should therefore balance efficiency with equity, paying greater attention to the protection of smallholders’ land rights and the enhancement of their capacity for development.
[Objective] China is the world's largest natural gas importer, and the security of natural gas import is threatened by multiple risk factors. The systematic assessment and forecasting of China's natural gas import risks can provide policy references for ensuring the security of natural gas import in China. [Methods] This study constructed a assessment framework for natural gas import risks by identifying the risk factors in natural gas import according to the stages and links of the natural gas import supply chain. Then, the framework was adopted to assess the risks of China's natural gas import from September 2006 to December 2022. On this basis, a deep learning algorithm, long short-term memory neural network (LSTM), was adopted to systematically forecast China's natural gas import risks and risks at each stage of the supply chain. [Results] (1) China's natural gas import risks generally experienced three evolutionary stages (fluctuating rise-fall-rise), and most supply chain risks increased with fluctuations. In recent years, the security level of China's natural gas import declined. (2) The dominant risks affecting China's natural gas import security evolved over time, showing a transition from diversification risk to dependence risk and then to availability risk. (3) China's natural gas import risks, availability risk, accessibility risk, and dependence risk were projected to rise with fluctuations, whereas diversification risk was projected to decrease with fluctuations. The country risks of about half of China's major natural gas suppliers were projected to rise with fluctuations or first decrease and then increase. The natural gas export potential of about one-third of China's major natural gas suppliers was projected to decline with fluctuations or first rise and then decline. [Conclusion] Overall, the current and future security situation of natural gas import in China is not optimistic. Given the rising trend and complexity of natural gas import risks, China should strengthen risk management of the natural gas import supply chain to ensure the security of its natural gas import.
[Objective] This study addresses the imbalance of resource loss and efficiency in the rare earth permanent magnet industrial chain, and provides decision-making support for efficient rare earth resource utilization and high-quality industrial development. [Methods] Combining dynamic material flow analysis (MFA), the super-efficiency SBM model considering undesirable outputs, DEA window analysis, and the GML index decomposition approach, this study systematically evaluated the neodymium metabolic characteristics, resource allocation efficiency, and driving factors of China's rare earth permanent magnet industrial chain from 1990 to 2021. [Results] (1) Material flow patterns differed greatly across industrial chain segments. Severe resource losses occurred in the upstream mining and smelting stages (cumulatively 164561 t). The midstream manufacturing segment showed prominent advantages in the global supply chain. Discarded consumer electronics accounted for 46% of downstream neodymium waste. Demand from clean-energy fields such as wind power grew rapidly, but these applications had not yet reached their peak waste-generation phase. (2) The resource allocation efficiency of the rare earth permanent magnet industrial chain presented a gradient pattern of low efficiency in the upstream, fluctuating efficiency in the midstream, and high efficiency in the downstream. Constrained by upstream inefficiency, the overall industrial chain efficiency left much room for improvement. (3) Technological progress was the core driving force for the improvement of total-factor productivity in the whole industrial chain. However, there was a “technology-efficiency” transformation gap in the upstream and midstream of the industrial chain, which restricted the improvement of overall industrial chain efficiency. [Conclusion] To promote efficient resource utilization in the rare earth permanent magnet industry, a chain-wide dynamic regulation mechanism should be established to optimize resource management, differentiated efficiency improvement measures should be implemented to mitigate efficiency gradients, and a technological innovation ecosystem should be built to tackle bottlenecks in technology transformation. This study provides systematic solutions for the sustainable development of the rare earth permanent magnet industry, and its coupled analytical method can serve as a reference for strategic resource management.
