Materials Extraction and Use within the Framework of Global Sustainable Development

Economic growth has been driven by the use of large quantities of materials such as stone, soil, metals, biomass, coal, petroleum, plastics, and ceramics. Their production and distribution are energy intensive. The availability, beneficiation costs, and flow of raw and processed materials vary among countries and are determinants of economic advantages that may accrue to well-planned economies. Globally, physical infrastructure development projects in economic sectors such as construction, agriculture, transportation, manufacturing, and energy production depend on material flows within and among countries. Direct and indirect displacement of materials has economic, environmental, and social impacts. The relationships among these impacts, scaled in time and space to specific projects and national economic development programs, are important in assessments of sustainable development.

Sustainable development has four important elements: economic development; population management; environmental/natural resources stewardship; and social equity. Materials use is strongly nested in economic development, as illustrated in Fig. 1, but it has ramifications throughout the other elements, as well as the social and physical infrastructure development systems that are schematically depicted in Fig. 2. Definition of material use indices according to the scheme presented by the World Resources Institute (WRI 2000) enables material flows within any economy to be assessed appropriately. Characterization of material flows is necessary for material-energy conversions, which is in turn essential to the projection of energy supply needs of regions and countries. The following flows are defined.

Segmentation of TDO into various material flow components allows better correlation of material flows with socioeconomic and environmental stewardship indices of countries. For example, information provided by WRI (2000) indicates that TDO for Japan and the United States were $21\mathrm{t}$ and $86\mathrm{t}$ per capita, respectively. However, DHF is much higher in the United States than in Japan due to material losses during mining operations on large expanses of land. With developing countries being the primary supplier of raw materials to technologically advanced countries for use in processing and manufacturing industries, DHF, which comprises materials that exit the domestic economy during the extraction stage of materials, tends to reach high proportions within TDO.

Research and development of new/advanced materials such as nanomaterials, ceramics, and polymers that have improved performance characteristics and are produced with higher energy efficiencies than traditional materials increases NAS of countries. Herein, the technologically advanced countries have advantages over developing countries due to their better research infrastructure and quicker conversion of research output to products. Indeed, as pointed out by Lastres and Cassiolato (1990), the production of advanced materials by the technologically advanced countries reduces their dependence on developing countries for the production of minerals and basic metals. Replacement of metals by plastics, ceramics, and various composites; improved techniques of material utilization and recycling; and environmental pressures have been identified (Villas-Boas 1990) as the reasons for the observable decline in the rate of growth of natural resource utilization globally which were at 70, 29, and 54% for crude oil, industrial minerals, and metallic minerals in the 1966–1973 period but declined for the same products, respectively, to 7, 16, and 7% in the 1973–1980 period.

Conceivably, despite the continuing advances in material development since 1980 that subtracts from TDO of countries, demand for, and use of materials by increased population; increased capacity to extract oil from shallow and deep seas; and beneficiation of metals from ores with low concentrations have combined to increase material use volumes. Assessments (Belda 2006) show that currently more people live in cities than in rural areas for the first time in history, and globally there are about 60 million new city residents each year. These developments generate high demand for materials and the energy needed to extract, transport, process, produce, and distribute them.

The search for advanced/high-performance materials has continued in basically every economic sector and country. The construction sector uses large quantities of materials annually. Increasing urbanization rates generate the high demand for construction materials for various forms of physical infrastructure. For example, Taiwan, with a land area of $\mathrm{36,000}{\mathrm{km}}^2$ and a population of 20 million, had a construction aggregate demand of 200 million metric tons in the 1990s (Hsiao et al. 2001). Data (USGS 2000) show that in 1998, 1.35 billion Mg of crushed stone and 1.0 billion Mg of sand and gravel were produced in the United States. Indeed, as estimated by Guggemos and Horvath (2003), the average utilization rate of sand and gravel in construction in the United States is $3.63\mathrm{t}∕\text{person}∕\text{year}$ out of a total per capita consumption of “newly mined” (not recycled) consumption of $21\mathrm{t}$ $\left(57\mathrm{kg}\right)$ per day (Earthworks-Oxfam 2004). In the construction sector, the need for energy efficiency and use of durable of materials has prompted research that will increase the NAS of countries. The key target should be the search for materials that can be developed and used at low overall cost, including energy, environmental, and other social costs. To the extent possible, locally available materials should be adapted to serve a wider array of human support functions. For many countries, this strategy requires intensification of research into material processing and material-energy conversions, as well as provision of incentives for the rapid introduction of new materials into commerce.