Industrial Ecology and Socio-Metabolic Research
Challenge
Materials are at the basis of human society. Urbanization, industrialization, and growing consumption
drive the demand for wood, concrete, steel, plastics, chemicals, and various technology materials.
Providing adequate access to modern and low-carbon energy services and adapting to climate change
further increase resource consumption, as new energy infrastructure and protective measures such as
dams and dikes need to be built.
The global use of natural resources has grown at an unprecedented rate, and the number of chemical
elements and their combinations used in modern technologies have multiplied. Consequently, the natural
resource endowment and the quality of the environment keep declining in most countries, especially in
the Global South, which in turn fuels economic, social, and geopolitical conflicts.
Currently, material production accounts for about 23% of global greenhouse gas emissions. This major
contribution to global warming, plus the large impacts of mining on land use change and water
consumption, highlight the need for research on how materials are linked to and can be decoupled from
environmental impacts and service provision to people by establishing a circular economy of materials.
Resilient and sustained supply of so-called critical materials and the large material requirements of
the transition to low-carbon energy are major global concerns involving materials. On the social side,
material extraction is often connected to struggles for environmental justice.
SEM Approach
Socio-economic metabolism (SEM) is a research paradigm that looks at material and energy turnover
and processing at the societal level. SEM researchers study human-controlled stocks and flows of
energy and materials and their links to social outcomes and environmental impacts.
Under the SEM paradigm, researchers have developed methods and established accounting approaches to
measure material use in the economy, model scenarios for transforming material cycles, and provide
policy advice regarding resource use constraints of policy interventions. Material flow analysis (MFA),
often combined with energy flow analysis (MEFA), is the basic accounting and modelling method of
scientific analysis of socio-economic metabolism. In-use stocks, the material stocks in the built
environment, are a key component of society’s metabolism, as they provide services such as shelter
and mobility and also provide the resources for future recycling.
Socio-economic metabolism is complex and includes many delays, like the lifetime of products in use,
and couplings, such as the different materials contained in a single vehicle. For another example,
many green technologies that reduce greenhouse gas emissions use critical minerals, making these
industries vulnerable to supply disruptions.
More detailed accounts of resource use and waste are needed to deepen the understanding of how
materials flow through the economy, where losses occur, and where efficiency can be improved.
Such detailed material flow accounts form the basis for assessing efficiency and circular economy
improvements for businesses and governments at the company, city, regional, national, and global scales.
The analysis may also focus on certain materials of concern because of their availability or toxic
capacity and will identify the impact of regulatory and engineering solutions to metabolic problems.
Dynamic MFA studies show how in-use stocks and material cycles evolve over time. They quantify the
accumulation of stocks in our economy, such as the material demand for the energy transition. A focus
of dynamic MFA is on industrial countries, such as Japan and China, which often depend on imports and
have large production industries and consumption levels.
Dynamic MFA helps identify future ‘urban mines’ (recycling potential) and allows us to estimate the
decline of ore grades as a response to growing demand. Thus, such studies provide necessary information
for assessing the potential of circular economy strategies, e.g., in the global building sector or
for cement.
Practical Applications, Current Trends, and New Research Avenues in SEM Research
MFA studies are now linked to supply chain assessment, e.g., via MFA-LCA combinations, and to
assessments of the economic implications of changed consumption and circular economy measures,
e.g., to estimate rebound effects. Increasingly, MFA studies are linked to social and environmental
impacts.
To study the social and environmental aspects of material use more systematically, the energy and
material service cascade offers a framework that combines the key elements of socio-economic metabolism
(material services, stocks, and flows) to human well-being on the one hand and materials to environmental
impacts on the other hand.
Different social and environmental links of material can be studied, as well as different decoupling
options along the cascade. The framework allows for coupling MFA studies to the assessment of legal
instruments and economic incentives at the different stages of the cascade, as well as exploring the
link between material stocks, product stocks, product functioning, service provision, and well-being.
The multi-stage cascade and its link to culture, lifestyle, regulations, and economics enable us to
systematically expand the traditional set of economic indicators to include well-being indicators
beyond GDP that measure how effectively basic human needs are being met, alongside high-level
information on material use, waste, energy use, emissions, and water use.
This refined understanding of human material use in the energy and material service cascade leads
to an expanded set of indicators that is critical to redesigning our provisioning systems to achieve
a good life for all within planetary limits.
Source: This text is part of an overview on socio-economic metabolism research written
by Stefan Pauliuk in his role as ISIE-SEM board section chair and published at:
https://is4ie.org/sections/metabolism/pages/40