O PORTUGAL

BRAZIL

SYRIA

500

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PER CAPITA GNP (U.S. DOLLARS)

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the morning he sleepily stills an alarm clock made of steel and glass, turns on lights made of glass and metals and powered by electricity generated by burning a fossil fuel and moved along metal wires, brushes his teeth with a toothbrush made from a petroleum product while standing on tile made from clay, looking into a mirror made from glass sand and mineral fluxes. His stove, refrigerator, dishwasher, air conditioner, washer, dryer, and disposal are made of metal and run by fossil-fueled electricity. The bricks and roofing of his home, the tile, bathtubs, washbasins, and windows are made from mineral resources as are the walks, patio, and paved driveway. Increasingly his clothing, carpeting, and draperies are made from nonrenewable resources. Of course, his automobile, his children's bicycles, and the buses and airplanes that take him to work or on business trips are made of metal and run on nonrenewable energy resources. His working day is spent in structures made of reinforced concrete, a combination of sand, gravel, crushed rock, portland cement, and steel. All the machines that serve him, either directly or indirectly, are mainly of mineral origin. The communications networks that link him to most of the rest of the world's people, are built largely from mineral materials.

The concepts of natural subsidy and net work profit

Important to an understanding of the role played in human society by energy and mineral resources are the concepts of natural subsidy and net work profit.

Life exists on earth by the grace of solar radiation, which provides the ambient temperature range within which man can live. It drives the winds and powers the hydrologic cycle. It provides the energy for plant

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growth and the light without which there would be perpetual night. Over millions of years a tiny part of the incoming solar radiation has been trapped in the form of plant and animal detritus under preserving conditions and turned into deposits of petroleum, coal, and natural gas. Whenever man can recover more useful energy or work from any portion of the natural energy system than he has to expend to recover it, he is the beneficiary of a natural subsidy (Fig. 7). The natural subsidy inherent in streams of falling water, forests, the fossil fuels, and mineral deposits, is unevenly distributed over the surface and within the crust of the earth.

The natural subsidy is possible only because the nonrenewable resources that man uses are the result of an enormous amount of work that he has neither to perform nor to pay for. In nature work is done in the conversion of solar energy into the chemical energy of plant food; in soil formation; in the continuous operation of the hydrologic cycle and the atmospheric wind system; in the concentration, preservation and transformation of tiny organic packets of chemical energy into deposits of the fossil fuels; in the magmatic, hydrothermal and sedimentary concentration of minerals; and in the crustal uplift and erosion of overburden that have made many fossil fuel and mineral deposits more accessible than they otherwise would be. All geochemical concentrations of minerals useful to man which can be recovered at a net work profit represent natural subsidy.

The subsidy is available only to those who possess the appropriate technologic keys, and the size of the subsidy depends on the quantity and concentration of the resource as well as on the technical efficiency of man's exploitation system.

FIGURE 7