Global pattern of the international fossil fuel trade: The evolution of communities Weiqiong Zhong a, b , Haizhong An c, d, e, * , Lei Shen f , Tao Dai a, b , Wei Fang c, d, e , Xiangyun Gao c, d, e , Di Dong c, d, e a MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, CAGS, Beijing, 100037, China b Research Center for Strategy of Global Mineral Resources, Chinese Academy of Geological Sciences, Beijing, China c School of Humanities and Economic Management, China University of Geosciences, Beijing, China d Key Laboratory of Carrying Capacity Assessment for Resource and Environment, Ministry of Land and Resources, Beijing, China e Open Lab of Talents Evaluation, Ministry of Land and Resources, Beijing, China f Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China article info Article history: Received 17 May 2015 Received in revised form 30 January 2017 Accepted 6 February 2017 Available online 7 February 2017 Keywords: Fossil fuel International trade Communities Complex network Emergy abstract In the international trade of fossil fuel, countries are clustering into communities. The evolution of the communities can reflect the underlying trade pattern. This paper provides a new perspective in analyzing the global pattern of international fossil fuel trade by quantitatively analyze the evolution of the communities. Emergy transformity are used to unify the three different fuels into the same unit seJ. This paper creates network models of fossil fuel as well as coal, crude oil, and natural gas and detected the clustering of the countries by an algorithm. Three types of Normalized Mutual Information are designed to measure characteristics of the evolution of the communities. A matrix is also designed to show the flows between each two communities. This study finds that the natural gas trade network is the most partitioned and the most stable. In 2013, natural gas exceeded crude oil had the highest similarity with the integrated fossil fuel trade pattern. 2012 was a turning point. The trade blocs and organizations play important roles. However, their effects are limited. The geographical factor is reinforced and the roles of the USA and Russia are becoming more important. Clusters containing Asia Pacific countries are less stable. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Coal, crude oil and natural gas are the most important types of energy in modern society. Because of the uneven distribution of production and consumption, these three fossil fuels flow between countries by international trade [1]. A better understanding of the evolution of the global pattern of the international trade of fossil fuel is important to policy makers. In the international trade of fossil fuel, countries are clustering into communities (or clusters) [2]. Some countries are closely related while others are loosely related. Trade blocs such as European Union (EU), North American Free Trade Agreement (NAFTA), and organizations such as Organi- zation of Petroleum Exporting Countries (OPEC) are well-known communities formed by trade agreements and/or political strate- gies. However, do the relationships among countries follow the same pattern in the real world? A detailed quantitative analysis of the clustering of the countries is needed to reveal the true pattern of the fossil fuel trade. This study introduces a new perspective to quantitatively analyze the evolution of communities in the inter- national trade of fossil fuels by complex network analysis and emergy theory, and provides a series of indexes and methods to portray the dynamic evolution of the global pattern which can be useful references to the policy makers. There are two questions need to be answered before we carry out the study. First, how to modelling the global pattern of inter- national trade? Most of the previous studies are based on tradi- tional international trade theories and models. For example, Halkos et al. designed a visual framework to display multi-region and multi-sector classical models, and it can illustrate the interactions among interregional and intersectoral economic activities [3]. Bernhofen took a set of conceivable outcomes as the primitive and * Corresponding author. School of Humanities and Economic Management, China University of Geosciences, Beijing, China. E-mail address: ahz369@163.com (H. An). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2017.02.033 0360-5442/© 2017 Elsevier Ltd. All rights reserved. Energy 123 (2017) 260e270