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The higher rates of growth of metals in use than
of apparent consumption are to be expected. Stocks of
metals in use would increase even if annual additions to
the stocks (apparent consumption) were to remain exactly
the same for each successive year. Growth rates of
annual apparent consumption represent what is, in effect,
the first derivative of the rate of growth of stocks of
metals in use, to which growth in GNP is more directly
related. Comparing rates of growth in GNP to rates of
growth in apparent consumption of metals has caused
metals to have been viewed as less important than they
actually have been.
While rates of growth in annual production and
apparent consumption of metals can be compared only
indirectly to the rate of growth in GNP, these rates of
growth are important insofar as they reflect demands
made upon resources; the higher the rates of withdrawal,
the more rapid is the decline in the quality of metals
resources that remain, and the more difficult is their
acquisition. On the other hand, the greater is the
amount of value generated by production per ton of
metal, the greater is the value of production that can
be obtained from the use of any given metals supply.
Mining and metals resources will be considered in the
next chapter, but increased efficiency of metals can
be considered here.