Metabolism is a biological concept to describe the chemical conversion of material and energy by organisms to sustain reproduction. Social metabolism by analogy implies that societies organize - similar to organisms - material and energy flow with their natural environment (and also by way of imports and exports), for their sustenance and reproduction. Much of these flows end up as stocks (or built infrastructure) to provide critical services to society such as transport, education, health, energy, and food security. These stocks, in turn, need to be maintained through flows, creating a dynamic feedback loop. The quantity and quality of flows a society will require over time will depend on the type and amount of stocks a society builds to deliver the necessary services. This is referred to as the material "stock-flow-service" nexus.

Sustainability at its core means the ability of a socioeconomic system to maintain its social metabolism at the lowest environmental cost while enhancing human wellbeing. Industrial Ecology (IE) tools such as material and energy flow analysis (MEFA), material stock accounting (MSA), and life cycle analysis (LCA) are most commonly used to quantify resource throughput through socioeconomic systems across time and space. The emphasis is on society’s resource use and resource efficiency at multiple scales.

Social metabolism studies aim to provide a number of potential sustainability solutions. For example, resource decoupling (i.e. reduce the material throughput of economies relative to economic growth), circular economy (i.e. move processes away from linear to the closed-loop material cycle), industrial symbiosis (where wastes and by-products from one process are inputs to another), and resource cascading (when a resource is used repeatedly in different applications to reduce the use of virgin materials, as well as reduce waste).

Only recently have scholars begun to analyze islands through the lens of social metabolism. Islands are excellent systems for such studies. Not only does the clear boundary of islands simplify tracking resource flows, but the limited resource availability and carrying capacity of islands warrant better tracking and management of these inputs and outputs. As the saying goes: “You can’t manage what you can’t measure”. Island metabolism studies provide data and information to planners and policymakers on the physical basis of island economies, that is, on the quantity and quality of material and energy domestically produced, imported, transformed, used, and discarded. Concepts of resource decoupling, circular economy or industrial symbiosis can be helpful to address several island sustainability problems such as waste, resource dependency, climate vulnerability, and a range of environmental and social risks. By studying the metabolism of islands, we can support island societies to transition towards more sustainable modes of production and consumption, and enhance social wellbeing.

Seminal works for beginners:

Fischer-Kowalski, Marina (1998): Society's Metabolism. The Intellectual History of Material Flow Analysis, Part I, 1860 - 1970. Journal of Industrial Ecology 2(1), pp. 61-78.

Deschenes, P. J., & Chertow, M. (2004): An island approach to industrial ecology: towards sustainability in the island context. Journal of Environmental Planning and Management, 47(2), 201–217.

Singh, Simron J., Grünbühel, C. M., Schandl, H. and Schulz, N. B. (2001): Social Metabolism and Labour in a Local Context: Changing Environmental Relations on Trinket Island. Population and Environment 23(1), pp. 71-104.

Haberl, H., Wiedenhofer, D., Erb, K.-H., Görg, C., & Krausmann, F. (2017). The Material Stock–Flow–Service Nexus: A New Approach for Tackling the Decoupling Conundrum. Sustainability, 9(7), 1049.