Natural Resources and Population

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Human survival in places with clement climate requires only a constant supply of oxygen and drinkable water and digestible food; no more was available to human's earliest hominin ancestors. Subsequent evolutionary processes, marked by extraordinary increase of brain capacity and resulting in the worldwide radiation of human species, extended the human need for natural resources to phytomass and zoomass (poles, branches, leaves, fibers, skin, sinews, furs, bones) used to construct simple shelters, clothes, and tools. Transition from migratory foraging to sedentary existence based on permanent agriculture expanded the requirements to a much greater variety of resources that were increasingly subjected to some kind of processing–relatively simple milling and fermenting of grains, more complicated firing of clays to produce bricks and ceramics, or elaborate smelting and forging of a growing array of metals.

Acquisition and Use of Resources

This trend of widening resource acquisition and more sophisticated processing has been accelerating since the mid-nineteenth century. It has become difficult to think about any part of the Earth's natural capital that is not either already exploited or seen as a potentially useful input into some process or service. And human ingenuity keeps creating new resources even from the oldest and simplest materials. Sand (silica dioxide) got its first upgrade more than 2 millennia ago when the Roman engineers began using it to make concrete. The second, unheralded, elevation of sand came in 1918 when Jan Czochralski discovered how to grow large silicon crystals. Half a century later his process was deployed on an industrial scale to produce thin semiconductor wafers for photovoltaic cells that power satellites and that may, within a few generations, produce a large share of electricity.

Determining the Magnitude of Resource Bases

Resource base is the totality of a commodity present in the biosphere and in the Earth's crust. Although this changes naturally only over long periods of evolution, measuring it is seldom easy. Resource base quantification is relatively straightforward only for such entities as the total volume of surface water, the area of potentially arable land, or the aggregate volume of wood in a particular forest biome. In contrast, it is very difficult to measure not just minerals in the Earth's crust but also such diffuse and mobile living resources as ocean fish and marine mammals. Not surprisingly, these uncertainties lead to recurrent disputes about the ultimate amounts of globally recoverable fossil fuels and ores (engendering periodic "running out" scares) and make the management of ocean fisheries or conservation of endangered marine mammals a matter of continuing controversy (American estimates of whale numbers are much below Japanese estimates).

Renewable and Nonrenewable Resources

Moreover, the distinction between renewable and nonrenewable resources is not as clear as it may seem at first. Clearcutting of forests on steep slopes, overgrazing of pastures, and improper agronomic procedures are among common malpractices that open the way for excessive soil erosion, loss of organic matter and plant nutrients, decline in soil's moisture-storing capacity, and, in arid areas, an often irreversible desertification. These environmental changes may make it impossible to restore the forest or to sustain highly productive grazing and crop cultivation. Similarly, excessive withdrawals of surface water for irrigation and industrial and urban uses can eliminate (entirely or seasonally) previously copious river flows; neither the Colorado River nor the Huanghe (Yellow River) now reach, respectively, Baja California and Bohai Bay for most of the year. They can also deplete aquifers–such as the great Ogallalla reservoir that underlies the croplands of the Great Plains or the huge aquifers under the Saudi Arabian sands whose water irrigates wheat in the midst of a desert–at rates far exceeding the pace of their slow natural recharge.

Historical Debates on Resource Scarcity

Concerns about the balance between human numbers and natural resources have exisited ever since the beginning of modern industrial expansion when, in 1798, they were eloquently formulated by T. R. Malthus (1766–1834) in the first edition of his An Essay on the Principle of Population. Malthus's pessimistic conclusions–that "the power of population is indefinitely greater than the power in the earth to produce subsistence for man" and that "this natural inequality … appears insurmountable in the way to the perfectability of society"–have been surely among the most cited sentences of the nineteenth and twentieth centuries. In the second (1803) and subsequent editions of the essay, however, Malthus was more sanguine. In fact, the true Malthusian bequest is not a message of despair but a judicious mixture of understandable concern about the human future and confident hope for progressive solutions, a judgement that continues to be vindicated by gradual improvements of the human condition.

The economist David Ricardo (1772–1823) raised another concern regarding agricultural resources in The Principles of Political Economy and Taxation, published in 1817. He argued that the new land brought into cultivation as population grows will be steadily less fertile, and thus its produce increasingly costly. Within a few generations these worries had receded, thanks to the unprecedented availability of extrasomatic energies. Massive flows of fuels and electricity that are used to produce and to power the field and processing machinery and to synthesize agricultural chemicals have virtually eliminated hard physical labor in modern food production and turned the farmers in affluent countries into mere controllers of inanimate energy flows. The same process is underway in all rapidly modernizing low-income countries.

A third kind of worry was about running out of mineral resources. In 1865 William Stanley Jevons (1835–1882), one of the leading economists of the Victorian era, published The Coal Question, in which he rightly connected the rise of British power with the widespread use of coal converted to the mechanical energy of steam but wrongly concluded that coal's exhaustion must spell an inevitable demise of national greatness. In forecasting coal demand he made the two perennial errors of long-range forecasting by vastly exaggerating future demand for the fuel and grossly underestimating human inventiveness. After examining all supposed substitutes for coal (wind, water, tides, atmospheric electricity, peat, and petroleum) he concluded that it is "of course … useless to think of substituting any other kind of fuel for coal" and that future advances in science "will tend to increase the supremacy of steam and coal."

As it turned out, his worries were groundless. During the first years of the twenty-first century, rapidly dwindling numbers of British miners are extracting less coal every year than does Colombia or Turkey, not because the United Kingdom has no coal left (its remaining reserves are a hefty 1.5 billion tons), but because the country has little need for it as it has become the world's ninth largest producer of crude oil and the fourth largest producer of natural gas and a substantial exporter of both of these hydrocarbons.

Future Resource Supplies

But these realities do not mean that concerns about the scarcity of natural resources and about their role in economic growth have disappeared; they receded during the last decades of the nineteenth and during the first half of the twentieth century, but its second half was punctuated by flare-ups of such worries even as the costs of all basic commodities were steadily declining or, at worst, remained fairly stable. These apprehensions ranged from the 1952 warning by the Paley Commission that the United States does not have all of the material resources necessary for its development to the latest round of predictions about an imminent peak (before 2010) of global oil extraction and the subsequent inexorable decline of world oil supplies. Most famously, in 1973 the modeling study Limits to Growth predicted that, according to its "standard" world model run, the global economy and the Earth's population will collapse "because of nonrenewable resource depletion" and an unbearable spike in environmental degradation well before the end of the twenty-first century.

New discoveries, resource substitutions, technical innovation, economic adjustments, and extensive global trade in relatively scarce commodities have repeatedly turned these catastrophically framed scenarios into yet another set of failed forecasts. Britain's experience is an excellent example of a universal trend of resource substitutions evident not only in transitions to new sources of energy (the post-1850 sequence being wood, coal, crude oil, natural gas, new renewables) but also in shifts in using structural materials (in machine construction: wood, iron, steel, aluminum, composites; in buildings: wood and stone, bricks, concrete, steel and glass) or in the ways people communicate across long distances (running messengers, horse riders, wired telegraphy, wireless broadcasting). The last sequence is a perfect example of dematerialization, a broad civilizational trend toward using smaller specific amounts of resources.

Evidence of this admirable trend is everywhere, whether measured in macroeconomic terms (e.g., consumption of primary energy or basic metals per unit of GDP) or expressed as resource needs for particular products or services (engine mass/installed automobile power; gasoline consumed/distance; irrigation water or nitrogen fertilizer per unit of crop yield). And in some instances the need for a particular resource has entirely disappeared; reserves of copper ore deposits and the price of the metal used to be a recurrent worry for a society depending on highly conductive wires–but they are of little concern for cellular telephony, satellite TV, and the Internet. Innovative substitutions have not been the only means of dematerialization and of allaying concerns about the exhaustion of mineral resources: higher efficiencies of resource use and increasing rates of recycling have extended the available supplies and helped to lower the cost of virtually every mineral resource.

As a result, and in spite of growing populations and advancing economies, national and global consumption of some key resources has actually declined in absolute terms. Perhaps the most surprising example in this category has been the decline in water withdrawals in the United States; between 1980 and 1995 the U.S. GDP expanded by nearly 55 percent (in real terms) while the country's total water use fell by 10 percent. However, for many resources, from aluminium to urea, the trend of relative dematerialization has been going hand in hand with increasing rates of absolute consumption.

Even so, there have been hardly any exceptions to the long-term secular decline of inflation-adjusted commodity prices. No insurmountable shortages of nonrenewable resources are foreseen during the twenty-first century, which should be marked by the necessarily slow but epochal transition to renewable sources of energy and by a slow shift toward many bioengineered materials.

The main resource challenges of the twenty-first century will be concerned with environmental impacts of resource use rather than with resource availability. The most intractable global concern is the loss of those natural resources that are critical for maintaining irreplaceable environmental services. Destruction of tropical and marine biodiversity and large-scale transformation of remaining natural ecosystems due to human interference in grand biospheric cycles are high on this list of worries. Combustion of fossil fuels and deforestation alter the global carbon cycle; applications of nitrogen fertilizers and emissions of nitrogen oxides from combustion introduce large amounts of reactive nitrogen into the biosphere; sulfur, and nitrogen, oxides are the principal cause of acidifying deposition. A dire but conceivable environmental scenario would have the biosphere experiencing more pronounced and faster global warming than at any time during the last 1 million years.

Regional Resource Scarcities

There are justifiable local and regional concerns about the future availability of some key resources. The most acute of these is the availability of water in some 40 arid African and Asian countries extending from Mali to Iran. As with nearly every other perceived resource scarcity, a large part of the solution to water shortages lies not in tapping new sources but in reducing considerable waste (caused by low and subsidized prices and by poor efficiencies of water use due to improper irrigation, outdated industrial processes, and leaky urban distribution) and by deploying available techniques that allow for virtually perfect water recycling.

Another effective solution to these local and national resource scarcities is through trade based on comparative advantage. As production of a kilogram of grain needs more than 1000 kilograms of water, rainy and fertile places have an obvious comparative advantage in grain production. In a rational world there would be no wheat produced in Saudi Arabia, nor any alfalfa in California. Unfortunately, extensive government subsidies (amounting globally to more than $1 billion per day for agricultural production alone) lead to an enormous misallocation and waste of resources. Even a very conservative appraisal of the world's natural resources cannot find any reasons why they could not support dignified life for a population that may be finally approaching the global plateau and that may avoid yet another doubling. But given the naturally uneven geographic distribution of every major resource it would be impossible to achieve that goal through national and regional autarky.

Cornucopians and Catastrophists

Cornucopian dismissal of any concerns about the quantity and quality of the world's natural resources derives from the record of indisputably admirable innovation, technical fixes and socioeconomic adjustments that have been able, so far, to prove all modern Cassandras wrong. Indicators that matter point in the right direction as resources have been able to support a higher quality of life for larger populations: infant mortality is down, life expectancy, income, and schooling rates are up. In contrast, catastrophists see the emerging scarcities of some natural resources, and equally indisputable examples of worldwide environmental change and degradation, as harbingers of worse things to come. Some important indicators that matter point in the wrong direction: the Earth's biodiversity is declining, simplification and homogenization of ecosystems is progressing, and the signs that the biosphere is in trouble can be found anywhere from the rapidly rising incidence of childhood asthma to the fact that the 1990s were the warmest decade since the beginning of instrumental records.

Both the cornucopians and the catastrophists are right–and they are both wrong. The historical record is both inspiring and discouraging; the future looks very promising but also quite perilous. The civilization of the early twenty-first century would not be the first whose mismanagement of resources (as opposed to their actual availability) would be the cause of its decline or even of its demise. But our innovative drive, our technical prowess, and our understanding of how the biosphere works gives us the capacity to avoid that fate. The outcome is not preordained one way or the other but will be determined by our choices.

See also: Carrying Capacity; Deforestation; Ecological Perspectives on Population; Energy and Population; Food Supply and Population; Land Use; Limits to Growth; Sustainable Development; Water and Population.


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Dahlberg, Kenneth A., and John W. Bennett, eds. 1986. Natural Resources and People: Conceptual Issues in Interdisciplinary Research. Boulder, CO: Westview.

McLaren, Digby J., and Brian J. Skinner, eds. 1987. Resources and World Development. Chichester, Eng.: Wiley.

Simon, Julian L., ed. 1995. The State of Humanity. Oxford: Blackwell.

Smil, Vaclav. 1994. Global Ecology. London: Routledge.

——. 2002. The Earth's Biosphere: Evolution, Dynamics, and Change. Cambridge, MA: MIT Press.

Vaclav Smil

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Natural Resources and Population

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