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Conventional construction materials which rely on a fossil-based, nonrenewable extractive economy are typically associated with an entrenched linear economic approach to production. Current research indicates the clear interrelationships between the production and use of construction materials and anthropogenic climate change. This paper investigates the potential for emerging high-performance biobased construction materials, produced sustainably and/or using waste byproducts, to enable a more environmentally sustainable approach to the built environment. Life-cycle assessment (LCA) is employed to compare three wall assemblies using local biobased materials in Montreal (Canada), Nairobi (Kenya), and Accra (Ghana) vs. a traditional construction using gypsum boards and rockwool insulation. Global warming potential, nonrenewable cumulative energy demand, acidification potential, eutrophication potential, and freshwater consumption (FWC) are considered. Scenarios include options for design for disassembly (DfD), as well as potential future alternatives for electricity supply in Kenya and Ghana. Results indicate that all biobased alternatives have lower (often significantly so) life-cycle impacts per functional unit, compared to the traditional construction. DfD strategies are also shown to result in −10% to −50% impact reductions. The results for both African countries exhibit a large dependence on the electricity source used for manufacturing, with significant potential for future decarbonization, but also some associated tradeoffs in terms of acidification and eutrophication.

Zinc is a key metal of industrial society that saw an unprecedented growth of its use between 2000 and 2010, largely driven by demand in China. Nonetheless, a contemporary understanding of multi-level stocks and flows of zinc is lacking. This paper presents the cycles of relevant countries, eight world regions, and the globe for 2010, relying on material flow analysis (MFA) for results that have the potential to inform policy makers and future research. We estimate the global zinc end-of-life recycling rate at 33%, which helps achieve a 27% of fabricated zinc coming from secondary sources. Most losses occur in waste management, most of it in the end use sectors construction and transportation. Increasing collection rates in these two sectors should be a priority for closing the zinc cycle. China dominates the global anthropogenic zinc cycle, and relies on primary zinc from Latin America and the Caribbean and Oceania to support its zinc demand. Government and industry in Europe and North America should anticipate shifts in exports of their zinc-containing scrap due to the growing availability of Chinese end-of-life zinc. Further research combining this study with scenario analysis could provide the knowledge base to answer questions related to this issue.

Decision-makers traditionally expect "hard facts" from scientific inquiry, an expectation that the results of material flow analyses (MFAs) can hardly meet. MFA limitations are attributable to incompleteness of flowcharts, limited data quality, and model assumptions. Moreover, MFA results are, for the most part, based less on empirical observation but rather on social knowledge construction processes. Developing, applying, and improving the means of evaluating and communicating the reliability of MFA results is imperative. We apply two recently proposed approaches for making quantitative statements on MFA reliability to national minor metals systems: rhenium, gallium, and germanium in the United States in 2012. We discuss the reliability of results in policy and management contexts. The first approach consists of assessing data quality based on systematic characterization of MFA data and the associated meta-information and quantifying the "information content" of MFAs. The second is a quantification of data inconsistencies indicated by the "degree of data reconciliation" between the data and the model. A high information content and a low degree of reconciliation indicate reliable or certain MFA results. This article contributes to reliability and uncertainty discourses in MFA, exemplifying the usefulness of the approaches in policy and management, and to raw material supply discussions by providing country-level information on three important minor metals often considered critical.