A Growing Opportunity for Material Flow Analysis
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Now is an excellent time to build on the early successes of material flow analysis (MFA) to inform national and global environmental policy. MFA can help us address what complexity theory calls persistent environmental problems, those long-standing issues that are linked to the structure of our economy. In addition, MFA can help us understand emerging issues that are connected to widespread societal change. As flows of materials underlie society's well-being, MFA has great potential to inform the next generation of environmental (and other) policies through the illumination of materials use and associated emissions patterns. Analogies can be drawn to economics and energy analyses, which have more prominence in policy-making circles.
A recent shift in national priorities along with more careful attention paid to the interconnectedness of national policy issues brings a window of opportunity for MFA…. [T]here is a growing need for methods and analyses that address the secondary and tertiary implications of energy supply and demand; the green economy; international supply chains and material production; and underlying drivers of nonpoint source pollution.
Allen (2008) stated that analytical methods, government organizational capacity to collect and analyze data, demand from policy makers, and actual use will all be important for MFA to successfully be taken up by the U.S. policy community. Although the MFA practitioner has little control of government organizational capacity or actual use of his or her analyses, he or she can draw on insight into policy demand to inform his or her work. Thinking with some specificity about environmental policy problems that are important, urgent, and difficult to solve with traditional risk-assessment tools can help illuminate where the demand for future methods may be. MFA practitioners who would like to be policy-relevant can take inspiration from persistent or emerging challenges for the environmental policy community.
Today's Window of Opportunity in U.S. Environmental Policy
In the past several decades, U.S. environmental policy and regulation have been guided by risk assessment. Regulations supported by risk assessment have been successful at addressing individual existing environmental problems. However, this traditional approach does not fully capture the connections and interactions among drivers of environmental impacts. Furthermore, it tends to support reactive rather than proactive policies.
A recent shift in national priorities along with more careful attention paid to the interconnectedness of national policy issues brings a window of opportunity for MFA in conjunction with other disciplines, such as economics. Specifically, there is a growing need for methods and analyses that address the secondary and tertiary implications of energy supply and demand; the green economy; international supply chains and material production; and underlying drivers of nonpoint source pollution.
Energy Supply and Demand
To address climate change and energy security, the United States, along with many other nations, is moving toward transforming its energy sector. The extraction, refining, processing, transport/transmission, and consumption of fuels and electricity, along with the construction of fuel and electricity production and transport/transmission infrastructure, are intertwined with material use and linked to environmental impacts at every stage of the life cycle. MFA could proactively inform material trade-offs and linked environmental implications between the various energy options (e.g., wind, solar, coal, conservation) in the context of the overall economy. MFA could be used to explore the actual and possible contribution of the energy sector (both infrastructure and operations) to overall national material intensity under various scenarios. Such analyses could highlight and characterize structural transformations in the material basis of the economy. Substance flow analysis (SFA) could be used to examine the flow of trace materials, such as gallium and indium, which are important for renewable energy. In general, materials-based analyses would be a good complement for the economics-based analyses that are already common for the energy sector.
Within the United States, there is increasing emphasis on “green jobs” and a “green economy.” As the full definition of green economy is still developing, it would be useful to draw on MFA to characterize a green economy's macro scale material basis. In addition, moving to a “green economy” begs for a proactive environmental approach, which includes constructively informing the development and application of new technology in addition to finding problems with what is already underway. It would be quite valuable for multi-scale MFA to help highlight where in the evolving material flow system greener technologies could have the largest positive overall effect.
International Supply Chains and Material Production
In the past several decades, supply chains have become more globally dispersed. Also, a ramp up in materials production, particularly in China, has significantly changed production and consumption patterns on a global scale. For example, though it has leveled off somewhat in the past year, steel production in China increased by more than a factor of five between 1994 and 2008 (USGS 1996, 2009).
In addition, there is increased complexity of products and materials, including increasing diversity of chemical elements used. For example, the 15 rare earth metals more than doubled in global production between 1990 and 2006 (USGS 2002, 2009), in part due to advanced technologies. These increases in quantity and diversity of materials used have been more rapid than ever before encountered. All of these changes have environmental implications, which MFA can help illuminate.
Nonpoint Source Pollution
Though there is always more work to do, U.S. environmental policy has successfully addressed much point source pollution through traditional risk-assessment-based regulation. The increasing importance of nonpoint sources (relative to point sources) suggests the potential value in increasing the focus on addressing the underlying drivers. MFA may help us reason through diffused or distributed environmental problems and their possible solutions. For example, understanding the linked flow of nitrogen in the economy and in the environment can help us address eutrophication of our waterways. Also, tracking dispersion of trace and heavy metals throughout product life cycles may highlight the best opportunities for environmental improvement.
To proactively address the environmental implications of energy supply and demand; the green economy; international supply chains and material production; and nonpoint source pollution, MFA must be combined with complementary methods, such as probabilistic modeling, behavioral modeling, and macroeconomics. Several attributes of these coupled analyses are important, including the following:
Recognize and Characterize Dynamic Systems Behavior
As stated by Ehrenfeld (2009), industrial ecology (IE) tools, including MFA, will increase their usefulness when they combine with other methods to capture system dynamics and complexity. Building on Ehrenfeld's arguments, feedback from the ultimate applications of MFA approaches can and should inform further methodological development and integration with complementary analyses, whether it is in dynamic modeling, analyzing uncertainty, incorporating economics, or linking to behavioral models. It would be very valuable to have dynamic models that capture some of the underlying mechanisms driving materials flow. Then, MFA practitioners could explore possible futures in addition to describing the present state and historical conditions. Also, analytical tools incorporating underlying mechanisms of material flow could potentially lead to exploration of nonobvious relationships, interdependencies, and boundary issues. These analytical methods would inform an environmental policy that strives to influence the process of system change and that complements the traditional command and control approach.
Estimate with Incomplete Information
It is the nature of science to yearn for more data, and IE is no exception. Certainly, better data are required to fully inform the understanding of current state of materials flow and trends over time. However, one paradox is that when a material flow system is still developing (and therefore encompassing some degree of uncertainty), this is where the most opportunity lies to influence its impact on society. Prospective analyses based on mechanistic models are required to address this opportunity. Prospective analyses would be invaluable for informing environmental policy in such a way that the policy influences the process of a change that is felt throughout the economy, such as in shifting the energy sector. In this way, MFA may help to inform the underlying infrastructure for new sectors to reduce overall environmental impact.
Link to Environmental Stressors and Impacts
One of the intuitive aspects of MFA is that the material “weight” of an economy is linked to its multimedia environmental burden through product life cycles. In other words, environmental impact is linked to the overall quantities of materials that are processed and transported in addition to fate and transport of individual toxic materials. SFA can help us understand underlying factors driving the environmental dissipation of heavy metals and other substances of concern. MFA more generally can help describe how an elevated environmental burden derived from larger quantities of material throughput may confound local environmental stressor hotspots. Work needs to be done to more precisely characterize these relationships between material flow and environmental burden.
For many reasons, now is an excellent time for MFA practitioners to strive to inform persistent and emerging U.S. environmental policy challenges. This means thinking with some specificity about important and difficult policy questions that could be addressed by MFA. Grappling with these questions will both inspire methodological advances in the IE field and help inform environmental protection for the 21st century.
The author would like to thank issue co-editor Kirsten Sinclair Rosselot for her thoughtful feedback. Although this article has been reviewed and approved for publication, it does not necessarily reflect the views of the U.S. Environmental Protection Agency and no official endorsement should be inferred.
About the Author
Diana Bauer worked at the U.S. Environmental Protection Agency in Washington, DC at the time the article was written. She led U.S. EPA extramural research programs and participated in government and academic societies developing research agendas for sustainability, green materials, green manufacturing, green building, transportation, and alternative energy. She is one of the principal authors of U.S. EPA's research strategy for sustainability. Her current position is with the U.S. Department of Energy.