Washington D.C., 3 September 2009 

In 2008, more than 1.4 billion tons of metals were produced globally – double the quantity of the late 1970s and more than seven times as much as in 1950. Since the mid-point of the twentieth century, a cumulative 40 billion tons of metals have been produced. This figure includes aluminum, arsenic, cadmium, chromium, copper, gold, lead, mercury, nickel, and steel. 

Following steady growth from the postwar boom years until 1974, world metals production leveled off during the next 20 years. The late 1990s, however, witnessed the beginning of a new expansion-one far more rapid than the previous one. This second expansion was largely driven by the dramatic growth of the Chinese economy. Consumption growth rates have also been high in India and South Korea, but much smaller in overall quantities than in China.

Average per capita metals use rose from 77 kilograms in 1950 to 165 kilograms in 1975 and 213 kilograms in 2008. But these global averages conceal the fact that metals consumption is still heavily concentrated in a small number of countries. For instance, U.S. per capita consumption in 2008 (380 kilograms) was roughly nine times that in China and 15 times that in India.

Among the broad range of metals that are mined for commercial use, a few stand out. Steel-produced from iron ore-is by far the most important in terms of weight, accounting for 95 percent of the total. Aluminum-derived from bauxite-is a distant second, followed by considerably smaller quantities of copper and zinc.

Still, weight alone does not tell the full story. A range of metals-such as arsenic, cadmium, chromium, mercury, nickel, and gold-have serious environmental impacts but are mined in comparatively small quantities. Across the array of materials extracted, mining has serious environmental consequences. It involves large quantities of waste, toxics, and removal of natural vegetation.

In 2005, the production of 10 key metals commodities led to more than 3 billion tons of waste materials (excluding so-called overburden removal-the dirt, rock, and other material removed to reach ores). This was four times the weight of the actual metals extracted. Principally as a result of declining ore quality, the flow of processing wastes is increasing faster than that of the metals themselves.

As noted, iron ore is used in steel production, with chromium and nickel being added to produce stainless steel. China, Brazil, and Australia are the leading iron ore producers. Global steel production has risen steeply, from 189 million tons in 1950 to more than 1.3 billion tons in 2008. But the recent global economic crisis translated into sharply reduced volumes and lower prices in late 2008, a development that carried over into 2009. China, with its economic stimulus program an apparent success, is currently the only growing market in the steel sector.

China's steel production skyrocketed from 66 million tons in 1990 to 500 million tons in 2008, which was 38 percent of the world's total. It was followed at a considerable distance in 2008 by Japan (119 million tons), the United States (91 million), Russia (69 million), India (55 million), and South Korea (53 million).

A decade ago, North America and Europe dominated steel use, using 44 percent of the world's total. Today China is the largest user with 36 percent, and other Asian countries account for another 22 percent.

Steelmaking is a highly energy-intensive process that releases large amounts of greenhouse gases. On average, producing 1 ton of primary steel results in emissions of about 1.7 tons of carbon dioxide (CO2).18 Technological advances over the past two to three decades have led to improved energy efficiency, greater use of byproduct gases and materials, and substantial reductions in CO2 emissions per ton produced.19 Still, these per-unit gains have to some degree been offset by surging production. Altogether, steelmaking accounts for 5-6 percent of CO2 emissions due to human activities and 27 percent of emissions from manufacturing.

Energy intensity and carbon emissions vary greatly from country to country. Steel mills in Italy, Germany, South Korea, and Japan are among the most energy-efficient worldwide. Russia and especially Ukraine are still relying strongly on outdated open-hearth furnaces. Steelmaking in India carries a heavy environmental burden due to the prevalence of the low-quality coal as an energy source. China contends with old and inefficient facilities, but the country is making major strides in modernizing its industry.

A growing amount of steel is now produced from recycled scrap material-the result of changing economics and environmental considerations. The International Energy Agency notes that "the amount of steel that is stored in capital stock is more than 10 times annual steel production." This "secondary" production accounts for about 35 percent of total steel output worldwide. Recycling saves 40-75 percent of the energy needed to produce virgin steel.

In Spain and Turkey, secondary steel production accounted for 88 and 87 percent of their total output, respectively, in 2008. Other countries with prominent shares of recycling-based production include Italy (77 percent), the United States (64), South Korea (52), Russia/Ukraine (48), and Germany (45). The share of recycled steel in Brazil, China, and India, on the other hand, is still considerably lower.

Aluminum is made from bauxite, a metal that is primarily mined in Australia, China, Brazil, and India. This lightweight yet strong material is mainly used in the automotive industry, the aerospace industry, buildings and construction, and packaging.

World primary aluminum production has grown from about 2 million tons in 1950 to 39.7 million tons in 2008. As with steel, dramatic changes have occurred in the lineup of major producers. From a share of slightly more than 40 percent in 1960, the United States is now down to less than 7 percent. China surged to take a commanding 34 percent share in 2008. Russia, the second largest producer, accounts for 11 percent, and Canada has 8 percent.

Accounting for roughly 3 percent of global electricity use, the aluminum industry is among the most energy-intensive sectors of the world economy. Typically, the smelting process releases 1.6 tons of CO2 per ton of aluminum and another ton of CO2 equivalent from perfluorocarbon emissions. The industry has become steadily more energy-efficient, however. Worldwide average energy use in smelting has come down from more than 50,000 kilowatt hours (kWh) per ton in 1900 to 25,000 kWh in 1950 and 16,000 kWh in 2000.

Producing aluminum from recycled scrap uses only 5-10 percent as much energy as making it from scratch.38 And by reducing the need to mine bauxite, scrap recycling helps to avoid toxic mining wastes.

World secondary production of aluminum grew steadily from 2.6 million tons in 1970 to about 9 million tons in 2000, or about 38 percent. Since then, however, trends have reversed, even as primary production continued to increase rapidly. In 2008, scrap-based production of 6.3 million tons was equivalent to just 16 percent of total production.

Japan's experience is unique in that it has almost completely abandoned domestic primary production of aluminum, switching instead to secondary production and imports. In the United States, secondary production from old (post-consumer) scrap accounts for 30 percent of supply, with new scrap (from production processes) at least doubling that share. In the European Union, secondary aluminum production has tripled since 1980, accounting for about 40 percent of total output. The Chinese government intends to increase use of secondary aluminum from today's 17 percent of the total to 25 percent by 2010.

Ends -- 

The Worldwatch Institute

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The author thanks Grecia R. Matos, Minerals and Materials Specialist at the U.S. Geological Survey, for her generous help in providing metals production data and her comments on a draft version of this piece.