Global transfer of salinization on irrigated land: Complex network and endogenous structure.

Increasing globalization intensifies land redistribution via global supply chains. Interregional trade not only transfers embodied land but also displaces the negative environmental impact of land degradation from one region to another. This study sheds light on land degradation transfer by focusing on salinization directly whereas previous studies have extensively assessed the land resource embodied in trade. To analyze the relationships among economies under interwoven embodied flows, this study integrates complex network analysis and input-output method to observe the endogenous structure of the transfer system. By focusing on irrigated land with higher crop yields than dryland farming, we make policy recommendations on food safety and proper irrigation. The results of the quantitative analysis show that the total amount of saline and sodic irrigated land embodied in global final demand are 260978.23 and 424291.05 square kilometers respectively. Salt-affected area of irrigated land is imported by not only developed countries but also large developing countries such as Mainland China and India. Exports of embodied salt-affected land in Pakistan, Afghanistan, and Turkmenistan are pressing issues, accounting for nearly 60% of total exports from net exporters worldwide. It is also demonstrated that embodied transfer network has a basic community structure of three groups due to regional preference in agricultural products trade.

A complex network perspective on embodiment of air pollutants from global oil refining industry.

The air pollutants emitted from oil refining industry could be transferred across borders through the increasingly complex global trade network. However, the specific structural features of the network remain unclear. Based on the Multi-regional Input-output method and complex network theory, we make a first attempt to trace six oil refining air pollutants embodied in the international trade. The results show that the overall character of the global oil refining air pollutants flow network exhibits small-world behavior, and each node of the network is strongly connected. Therefore, the refining emissions mitigation measures of one node could efficiently radiate to the other nodes connected to it, which provides essential opportunities for collaborative emissions reduction among countries. Besides, the individual characteristics of each node are distinguished, several key nodes dominate the embodied emissions throughout the global oil refining air-pollutants flow network. For specific countries, the United States, China, Japan, and the United Kingdom are the hub economics in importing embodied pollutants in the network, while Russia and Canada are the key exporters. Similarly, the critical paths with large flow still come from the trade between these key nodes. Our estimated results have great policy implications for reducing air pollutants emitted from oil refining industry and also have profound implications for environmental regulation and protection in the world.