The uneven distribution of global coal supply and demand markets has driven coal trade. Effectively characterizing the global coal trade pattern and exploring its evolutionary mechanisms are important for economic development and international energy security. Therefore, this study adopts complex network methods to construct global coal trade network (GCTN) from 1995 to 2021. Based on exploring the overall, individual, and motif structural characteristics of the network, the temporal exponential random graph model is adopted to explore the impact mechanism of endogenous and exogenous variables on the evolution of the GCTN. The research findings demonstrate that (1) at the overall level, the network size, closeness, accessibility, and reciprocity of global coal trade exhibit an increasing trend; (2) at the motif level, aggregation and bilateral reciprocity are the primary trade patterns that affect the formation and evolution of the GCTN that is different from the steady-state structures of the four common super-families and possesses unique characteristics; (3) at the individual level, the United States and European economies possess a higher degree of diversification in coal trade, while Australia and emerging economies exhibit higher coal export trade volumes. The RCEP economies, represented by Japan and South Korea, possess a higher import share. Additionally, the Netherlands plays a “transit station” role in the network; (4) the formation and evolution of the GCTN are influenced by endogenous mechanisms. Reciprocity, transmission closure, and convergence effects have a significant promoting effect on network construction. Ignoring endogenous mechanisms can lead to significant bias in empirical results.

中文翻译：

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探究全球煤炭贸易网络的内生结构及演化机制


全球煤炭供需市场分布不均，带动煤炭贸易。有效表征全球煤炭贸易格局并探索其演化机制对于经济发展和国际能源安全具有重要意义。因此，本研究采用复杂网络方法构建1995年至2021年全球煤炭贸易网络（GCTN）。在探索网络整体、个体和基序结构特征的基础上，采用时间指数随机图模型来探究其影响内生变量和外生变量对GCTN演化的影响机制。研究结果表明：（1）总体层面，全球煤炭贸易的网络规模、紧密度、可达性、互惠性呈现不断增强的趋势； （2）在基序层面，聚合和双边互惠是影响GCTN形成和演化的主要贸易模式，其不同于四个常见超家族的稳态结构，具有独特的特征； （3）从个体层面看，美国和欧洲经济体煤炭贸易多元化程度较高，而澳大利亚和新兴经济体煤炭出口贸易量较高。以日本、韩国为代表的RCEP经济体拥有较高的进口份额。此外，荷兰在网络中扮演着“中转站”的角色； (4)GCTN的形成和演化受到内源机制的影响。互惠、传输闭合、收敛效应对网络建设具有显着的促进作用。忽视内生机制可能会导致实证结果出现重大偏差。