When the nation's projected demands upon resources for the rest of the century are compared with estimates of supplies that can be reasonably expected to become available, a kind of resource-by-resource balance sheet emerges. The brief summaries that follow also suggest some of the problems that may arise.
Land. Present cropland acreage (around 470 million acres) can satisfy food and fiber demand during the next forty years, with acreage surpluses likely for more than half of this period. This can be done, however, only if increasing demand is accompanied by continuing and substantial improvements in crop yields—say 100 bushels an acre for corn, about double the present average, and 35 bushels for wheat, an increase of about 50 per cent.
Urban land requirements are projected at 45 million acres by 2000, more than double the 1960 acreage; recreation at 130 million acres, more than three times the 1960 figure. Requirements for other uses of land—highways and air fields, reservoirs and watersheds, and wildlife refuges—also will rise sharply.
Projected demand for forest products by the end of the century is so much larger than the foreseeable domestic supply that at present yields something like 300 million acres would have to be added to the existing 484 million acres of commercial forest land to meet requirements. This is unreasonable; the practical alternative is more intensive management of existing commercial forest land, along with intensified efforts to find substitutes, and perhaps larger imports.
All demands for land by the year 2000, each taken separately, add up to 50 million acres more than the 1,900 million-acre total area of the 48 contiguous states. This "deficit" suggests a need for increased multiple use of land and for more intensive management in general.
Water. The nation's total demand for fresh water is expected to keep growing at a rate at least equal to that of population. Irrigation withdrawals may increase by half by the year 2000; municipal use may double and manufacturing use quadruple. There is no prospect of water shortage on a nation-wide scale. Localized water shortages will not seriously impair continued national growth, although they may limit local economic growth. The supply estimates do not allow for any significantly large contributions to supply through technological gains. Substantial advances in destalinization have been made in recent years and more are expected. But the cost reductions now in prospect are not large enough to suggest that more than a small fraction of total demand for freshwater will be met in this way during the next few decades. Much is still to be learned, of both the theory and practice of weather modification.
In the East, severe pollution of water supplies will be the problem. The total supply is more than ample for the rest of the century for municipal, industrial, and agricultural uses; the question is how much of the total will remain fit to use, particularly for recreation. A variety of pollution abatement efforts will be needed, including action of industries and cities to reduce contamination and to treat wastewater more thoroughly, an additional storage to augment stream flow when necessary to dilute the concentration of wastes.
In the West, water is already scarce in many areas. With the growth of population and industry expected by the year 2000, losses from projected withdrawals will be, far greater than dependable throughout the year. The West will need not only new dams and reservoirs, long-distance transport water, water conservation, and perhaps desalinization, but also better allocation of water resources among competing uses. Industrial and municipal use of additional supplies of water appear to have higher economic priority than irrigation.
In the Pacific Northwest, irrigation will remain by far the largest contributor to withdrawal depletions. The distinctive water problem of the region as a whole is fuller realization, in cooperation with Canada, of the great hydroelectric potential of the Columbia River.
Energy. Total US demand for energy is expected to triple by the year 2000. At least through the 1970's, it appears that US energy requirements can be met at no significant increase in real cost and with no sweeping changes in the relationship between oil, natural gas, and coal. Toward the end of the century nuclear energy is expected to become important in the generation of electricity. The proportion of all energy, regardless of source, used in the form of electricity is expected to keep on increasing.
Coal requirements are expected to increase steadily throughout the period; but coal's share in total energy use in the United States probably will continue to decline, though not so fast as in the past twenty years. Successful gasification or liquefaction of coal could slow or even reverse this trend. So could delays in the assumed rise in nuclear generation of electricity. Coal reserves are ample for a much longer period than this century.
Oil and gas requirements are projected to keep rising during the next four decades. The cumulative requirements for both fuels are so large that even assuming that the nation would import 20 percent of the oil it uses over the forty-year period seems doubtful that the remaining requirements can be obtained from domestic deposits even if significant technological advances in finding and recovery. Other possibilities at home or nearby are extraction of liquid petroleum from the shales of the Colorado Plateau and tar sands of northern Canada, and gasification of coal into a high-Btu fuel. Farther afield, vast supplies of oil are known to exist in the Middle East, Venezuela, North Africa and elsewhere, and not unlikely to be found in parts of world as yet only sporadically explored, and there are good possibilities for long-distance shipment of natural gas in liquid form.
Nuclear-powered production of electricity should become significant during the period after a slow start in the late '60's. By 1980, less than 5 percent of all energy use and less than 20 percent of all electricity generation is projected to come from nuclear reactors. The share by the end of the century is assumed to be nearly half of all electricity and about 15 percent of all energy. Successful production of nuclear process heat reactors, for use in industry, would raise nuclear energy's share in the total.
Only 3.6 percent of the national total in 1960, hydropower for the nation as a whole declines to 2 percent in the projection for 2000. In certain regions, notably the Pacific Northwest, hydropower's share of total energy will remain much larger.
Nonfuel Minerals. Domestic requirements for most of the major metals are expected to grow faster than population. Steel requirements, for example, are expected to increase by 200 percent by the year 2000; aluminum by 800 percent; and even lead, a slow-rising metal, by 100 percent. Patterns of consumption will continue to change. In 1960, iron and steel accounted for 90 percent of the total volume of metals used in the United States, and aluminum for almost 6 percent. By the year 2000 these ratios are projected to have shifted to 79 percent and 17 percent, respectively. It is difficult to generalize about future adequacy of minerals, for each must be examined in the light of its own situation; and even then the unsatisfactory state of reserve and resource estimates and meager knowledge of the cost implications of new technology make many judgments precarious. New advances in methods of discovery and extraction could bring in larger supplies than it now seems safe to anticipate. So could more rapid gains in knowing how to use lower grades of ore. It seems clear, however, that for many mineral materials the United States will become even more dependent upon imports than it is now.
Salient points in the outlook for a few individual minerals are noted briefly in the paragraphs that follow.
Cumulative demands for iron and steel through the end of the century exceed currently identified domestic reserves of iron ore in this country by some 40 percent. At present the high cost of mining the large domestic deposits of low-grade ore qualifies only a small fraction for inclusion in US reserves. One may expect this fraction to increase in the coming years. World reserves of iron ore appear adequate to US needs, even with due allowance for rapidly growing needs in other countries.
World-wide reserves of bauxite, at present the preferred source of aluminum, are equivalent to world-wide cumulative demand, and advancing technology makes a gradual shift to lower-grade bauxite and high-alumina clays feasible with minimal effects on cost.
US reserves of copper are at or below 50 million tons, while the projected cumulative demand is 110 million tons. The non-communist world as a whole has reserves amounting to about half the needed supply. These reserves, however, are backed up by an ample reservoir of potential ore of low copper content—but not lower than what is now being mined profitably in the United States. Such potential ore can be used with only gradual cost increases, if any, through the end of the century.
Domestic reserves of lead amount to barely one-eighth of projected cumulative requirements, and to about one-third for zinc. For the whole non-communist world, roughly calculated requirements exceed the estimated reserves of both lead and zinc. There is some doubt whether this picture may not be unduly affected by the poor quality of the reserve estimates.
US demand for manganese, now about 1 million tons a year, is projected to triple by 2000. The United States is dependent on foreign supply. While in the non-communist world identified reserves barely exceed projected demand, there is to be a large potential for more production from new discoveries, slag heaps near steel mills, and sibley ocean-floor nodules; at same time manganese required per ton of steel may be subject to substantial reduction.
Reserves of nonmetallic nonfuel minerals appear adequate—rock and sand; salt; and potash phosphate for fertilizer. The Long run outlook for sulfur appears hopeful mainly because of world-wide increase in sulfur recovery from sour oil and gas. Plentiful supplies of alternative source materials, such as gypsum, could alleviate any temporary tightness that might develop over the next forty years.
A version of this article appeared in print in the June 1963 issue of Resources magazine.
