Metal Production and Greenhouse Gases

摘要

The construction and industrial minerals andmetals consumed annually in the US amount to about 2.3billion metric tons. Metals constitute a small fraction(<5 precent) of this total mass but play a much largerrole in economic development. In 1991, their production(SIC 33) required 2.4 EJ (10~18 Joules) of energy,representing 15.3 precent of US industrial energyconsumption, or about 2.7 precent of total US energyconsumption. Here we examine three metals, steel,aluminum, copper, that together represent over 98precent of all metal consumption by weight. Thecontinuing evolution of the technologies used for metalsproduction and the character of feed materials hassignificant impacts on this sector's energy consumption.To link energy usage with carbon emissions, we examinethe mix of fuels (i.e., coal, oil, gas, electricity) usedin metal production. Our analysis expands on the workof Forrest and Saekely~1 in assessing the contributionof primary metals production to greenhouse gas emissions.Technological advances in the second part of thiscentury have reduced considerably the energyconsumption per unit of metal and there is potential forfurther reduction of carbon dioxide emissions from metalproduction. However, increasing the fraction ofrecycled metals offers the greatest opportunity forlimiting CO_2 emissions and for conserving Earth resources.i Stanley-Thompson Professor of Chemical Metallurgy:Director, Earth Engineering Centerii Associate Research Scientist, Columbia Earth Institute