Insights

Materials societies accumulate in buildings, infrastructures, and products are a key element of social metabolism dubbed ‘material stocks’ in sociometabolic research. Globally, the fraction of all material extraction used to build new or replace / maintain existing material stocks has increased from just over 20% in 1900 to nearly 60% today. The remaining share consists of materials used for energy, food/ feed and other dissipative purposes. Most material stocks are in buildings and infrastructures, though vehicles and industrial machinery also play important roles.

Societies use physical resources (both stocks and flows of materials and energy) for production and consumption activities that provide essential services such as nutrition, shelter, mobility, education, healthcare, and others. Service provision almost always requires specific combinations of stocks and flows. For instance, providing living space requires material stocks in the form of a building, energy flows for heating, cooling or lighting, as well as material flows for maintenance.

The concept of a stock-flow-service nexus shifts attention toward the potential for delivering services with fewer and more environmentally sustainable resources. For example, well-designed buildings can offer comfortable living conditions while using minimal heating or cooling energy, whereas poorly designed ones may require 10-100 times more energy to deliver the same service.

The construction and maintenance of material stocks, as well as the biophysical flows required for their use, are usually supplied in complex, and often international supply chains. The resilience of supply networks hinges on the qualities and quantities of the materials as well as the structure of the supply chains themselves. Current sociometabolic methods are generally descriptive or static and thus ill-equipped to assess supply chain resilience. An important goal of REMASS is to develop methods and models that can account for disruptions and non-linear dynamics, including tipping points in socio-ecological systems.

Material stocks often require large investments and embody substantial value, making them important capital stocks. Their design often requires energy or material flows during use, thereby locking service provision into specific, and often unsustainable patterns of resource consumption. They are therefore central for understanding the malleability of social metabolism, i.e. the extent to which it can be shaped through purposive actions. Assessing these lock-ins and identifying options to transform existing stock patterns towards more sustainable configurations is thus a central objective of REMASS.

Over the past decade, socio-economic metabolism (SEM) research has made substantial advances in analysing the global copper cycle. Material flow analysis and environmental input–output models have focused primarily on mapping material stocks and flows across national and international supply chains, addressing key “what” questions: the magnitude and distribution of stocks and flows, the main producing, trading, and consuming regions, and the drivers of copper demand. However, approaches that rely largely on statistical data provide limited insight into why these patterns have emerged. Crucial “why” questions therefore remain unanswered: Why did certain firms and actors pursue strategies that resulted in the observed stocks–flows trajectories, why specific corporate strategies and technologies have prevailed, and why certain regions are integrated into global networks while others are marginalised. This gap also constrains the ability to address “how” questions central to sustainability transitions, including how goals such as reduced resource extraction and increased recycling align or conflict with existing corporate interests, and how national or international policies might effectively reshape copper supply chains.

Our research addresses this gap by proposing an analytical framework that integrates biophysical perspectives on material stocks and flows with political economy approaches, notably Global Value Chain (GVC) analysis. The framework is relational and dynamic, recognising that actor strategies both shape and are shaped by evolving stocks and flows, and that shocks and disruptions can trigger adaptive reconfigurations of supply chains. It also accounts for macro-level developments beyond the industry itself, such as global economic growth and climate policies. We apply this framework empirically to global copper supply chains by combining insights from a newly developed physical multi-regional input–output (MRIO) model, which traces copper flows along global value chains, with a novel qualitative dataset on the top 15 copper firms based on interviews, financial statements, market intelligence, and corporate and media sources. By mapping firm strategies, investment rationales, and regulatory contexts, we analyse how corporate and state interests interact to shape investment decisions and the evolving organisation of global copper mining and processing.

Through addressing these “what”, “why” and “how” questions within one analytical framework we ultimately seek to contribute to scientific and policy debates about the past, present and future of global commodities markets and opportunities and constraints in designing policies that reconcile the material demand of modern societies while addressing climate change and environmental destruction.