Global nickel trade network: Spatio-temporal evolution and cascading risks

The current prevalence of geopolitical rivalries and trade risks renders reliable access to nickel a strategic concern. This study employs a combination of complex network analysis and a cascading failure process model to examine the spatio-temporal evolution and cascading risks of the global nickel trade network from 2000 to 2022, thereby contributing to the understanding of global nickel ore trade and security. The results indicate a significant increase in global nickel ore trade, with the trade network becoming increasingly interconnected and efficient. The global nickel trade is concentrated in a limited number of countries, characterized by a scale-free distribution, small-world attributes, and high aggregation. A few hub nodes bear a disproportionate share of the cascading load, where disruptions targeting these nodes produce nonlinear, large-scale avalanches. The Philippines, Indonesia, and New Caledonia are identified as core countries in the nickel export trade, while China, Japan, and South Korea have emerged as significant importing nations in Asia. Overall, the impact of the nickel supply crisis has intensified with the increase in trade volume. The nickel supply risk in the United States has affected the largest number of countries, while the Philippines has had the most significant impact on the supply crisis in East Asia. Furthermore, the impacts of the nickel supply crisis in China have gradually expanded, extending to regions such as the Middle East, Europe, and North America by 2022. This expansion is anchored in direct trade linkages but is substantially amplified by indirect network spillovers, underscoring the complexity of cascading risks. Finally, policy recommendations are proposed to enhance nickel supply security.