Material Flows with Nexus of Regional Socioeconomic System

This beginning chapter aims to introduce the background, goal, and main contents of this book. First, it will introduce the materials and their flows through the socioeconomic system. The system composes all the material flows within its whole life cycle including mineral exploitation and transport, raw material production and processing, construction, operation and maintenance, and dismantling and waste disposal. To analyze the material flows in the socioeconomic system, the chapter then proposes the material flow analysis, a particular method widely used to analyze the material flows in the system. Considering the ‘nexus’ relationship among these materials and its great effect on the material flows and the related environmental impacts of the system, it highlights the material flows with nexus in the related studies. Moreover, the chapter points out that the book will explore the material flows with nexus in regional socioeconomic systems due to their regional differences. Lastly, the chapter gives a main introduction of each chapter discussed as follows.

This chapter aims to introduce the relationship between human and the environment, the concept of material, the concept and influence of material flows, as well as the concept and development history of material flow analysis. First, by introducing the relationship between humans and the environment, it explains the exchange of materials between society and the natural environment, as well as the related production and consumption processes, directly or indirectly contributing to the degradation of the earth. This helps to recognize the important roles of materials and material flows in the socioeconomic system. Subsequently, the chapter introduces the concepts of material and material flow, and discusses the impacts of material flows in the socioeconomic system. Then it introduces the concept and the development of material flow analysis. Finally, it uses case studies to demonstrate the practical applications of material flow analysis in the socioeconomic system.

The purpose of this chapter is to systematically introduce the methods of material flow analysis, which mainly include substance flow analysis, life cycle assessment, input–output analysis, and environmental footprint. These methods are widely used in the field of environmental science and sustainable development. By measuring and analyzing environmental indicators such as resource utilization, energy consumption, and waste emissions, they can reveal the environmental performance and sustainability of products or systems. In this chapter, we begin to introduce the definition and basic principles of these methods and discuss the background and characteristics. Subsequently, we summarize the development of these methods. Additionally, we elaborate the analytical framework of these methods and explain each step in detail. Lastly, in order to provide a clearer introduction to these methods, we present a specific example to illustrate the application of the methods. Here, we focus on the definition of system boundary in specific applications.

Agricultural production is crucial for maintaining the normal functioning of human society and promoting environmental sustainability. Agricultural production encompasses various components. In this chapter, we categorize agricultural production system into crop production system and animal production system. Crop production system is composed of fertilizer production and crop cultivation. Animal production system is composed of crop feed cultivation, breeding, and manure management. In recent years, there has been a growing concern about the environmental impacts of material flows in agricultural production. The material flows dominated by carbon, N, and P have been found to have the most significant impacts on the environment, regardless of whether they are in crop production system or in livestock production system. We aim to illustrate the environmental impacts of material flows (such as N flows and P flows) in agricultural production with some examples. We will apply life cycle assessment (LCA) method to demonstrate the nutrient flows in agricultural production.

The abundance and stability of coal resources make it an important raw material for industries such steel, construction, coal chemical, and coal-fired power generation. Among them, coal-fired power generation is an important component of China’s energy structure, with significant significance in promoting economic development and ensuring energy security. We first describe the importance of coal to various industries in society and then introduce the coal-fired power generation industry generated from coal as raw material. We also introduce the historical development of coal-fired power generation, including technological evolution and scale expansion. From the life cycle perspective, we analyze the material flows of the coal-fired power generation system. Finally, we present a case study on the life cycle of circulating fluidized bed (CFB) coal-fired power generation. We aim to use life cycle assessment (LCA) to explore the material flows of coal-fired power generation system and their impacts on environment. We hope use LCA to explore the flows of coal-fired power generation system deeply and provide a scientific basis for the sustainable development of the coal-fired power generation industry.

This chapter mainly introduces nexus theory and approach. Broadly speaking, the nexus approach is a tool for integrating systems, a platform for engaging stakeholders, and a method for exploring pathways for development. It is also a comprehensive tool to solve the challenges of global sustainable development. The appearance of nexus can be traced back to the early 1980s, and the relationship between two nodes (food-energy) was initially proposed. As time goes by, the nexus approach becomes more and more complex and diverse, and the number of nodes involved also increases. These nodes can be resource departments/systems or specific social-ecological problems. The nexus approach is very beneficial to the sustainable development agenda. Because the more nodes involved, the more potential reality can be captured. However, there is no consensus on key-related nodes covering all Sustainable Development Goals. The current problems of using nexus approach in the context of sustainable development include formulating implementation framework and determining relevant indicators and target values for evaluating trade-offs and synergies. Overall, the nexus approach has the potential to contribute to global sustainability, but further efforts are required to fully harness its benefits.

Food and water are essential for human existence, and energy is the key to human development. Access to these resources and their sustainable management are the basis for sustainable development. Efficient use of these limited or declining resources is essential to sustainability. The concept of the food-water-energy (FWE) nexus emerged from international conversations on resource security and sustainable development. The FWE nexus offers an analytic framework to better understand and systematically analyze the interactions between resource systems, the natural environment, and human activities across sectors and scales. This chapter is composed of five sections: food-water nexus, water-energy nexus, food-energy nexus, food-water-energy nexus, and food-water-energy-carbon nexus. Food-water nexus is mainly concerned with agricultural production, where the amount of water withdrawn far exceeds the amount of water used by humans in other ways. Water-energy nexus is primarily concerned with water use in power generation, but is also indirectly linked to hydrological changes associated with hydropower development. Food-energy nexus not only details the relationship between the food system in terms of energy consumption for food production and the energy system in terms of food provision for energy production, but also analyzes the possible environmental problems in the interrelationship. Meanwhile, this chapter will describe food-water-energy nexus and food-water-energy-carbon nexus with two case studies.

The chapter aims to provide a holistic understanding of the role and impact of material flow with the nexus in the socioeconomic system, offering both theoretical frameworks and practical examples. The chapter begins with describing the origins of the nexus approach and the material flow analysis approach and their roles in the socioeconomic system, as well as how the nexus approach affects material flows in the socioeconomic system. Next, it presents an analytical framework of integrating material flow analysis with nexus approach. Then, it introduces a case study to illustrate the application of the framework. Furthermore, the chapter explores the relationship between sustainable development and material flows within the nexus, emphasizing the implications of this approach for sustainable development across agricultural, industrial, and urban sectors. To provide a comprehensive understanding, the chapter used two case studies to represent the application of the material flows with nexus approach. These case studies offer practical examples of how the approach is implemented and its potential outcomes within different socioeconomic contexts.

It is helpful and crucial to analyze material flows with nexus in the regional socioeconomic system. However, more methods and better-operationalized research should be explored to identify the complex and various human activities. This last chapter summarizes and proposes several major directions for the studies of material flows with nexus in the socioeconomic system.