||Parts of the physical environment that are considered useful for satisfying human needs and wants. They exist independently of humankind, and in varying, but usually physically finite, quantities. People identify particular properties, substances and organisms in nature as a \'resource\'. Their value, scarcity and usefulness are also socially defined; as Zimmerman (1951) noted, \'Resources are not; they become.\' Human needs and wants change through time, therefore the means of satisfying these needs and wants must also change. Additionally, changes in technology and knowledge can lead to what Zimmerman (1951) called the \'neutral stuff\' of nature being identified as a resource, e.g. rubber became a resource after Charles Goodyear discovered the vulcanization process in 1839. The opposite of resources are what Zimmermann (1951) identified as \'resistances\', which includes pests and weeds. Recent work in the geography of plants and animals looks at the construction of \'pests\', and their treatment by humans intent on preserving resources (Thorne, 1998). A perspective of \'resourcism\' (i.e. viewing the world as resources to be used by humans) may overlook the importance of the ecosystem in which the \'natural resources\' are embedded. This could lead to policies that recognize the importance of the natural resource, but little else, i.e. the fish without the water.
While the terms \'natural resources\' and \'resources\' are often used interchangeably, sometimes a distinction is made between them, with resources being defined more broadly to include things such as technology, human labour and ingenuity. It is on this basis that Julian Simon (1994) argues against ideas of resource depletion and notions that there are limits to growth. It is difficult to justify resources as being \'natural\' when increasingly they are being planted, bred or managed by people, e.g. plantation forestry, fish farming.
A distinction is sometimes made between \'stocks\' (natural resources that have taken millions of years to form and are considered nonrenewable, e.g. minerals and fossil-fuels) and \'flows\' (natural resources that are naturally renewable within a short timespan, e.g. solar radiation and tidal power). Rees (1989) posits a Natural Resources Continuum ranging from exhaustible to infinitely renewable natural resources. The middle ranges of this continuum include natural resources that are renewable dependent on the use levels and human investment, i.e. resource management. The term \'natural assets\' is sometimes used, e.g. Rees and Wackernagel (1994), by which the authors include material resources (e.g. petroleum, forests) but also process resources (e.g. photosynthesis, waste assimilation) for which MacNeill et al. (1991) use the term \'ecological capital\'.
Recent work in the broadly defined field of sustainable development has sometimes seen the use of the term \'natural capital\' instead of \'natural resources\' (Pearce et al., 1991; Jannson et al., 1994). Natural capital is a financial metaphor that treats the earth like a bank account, and suggests it is wise for humans to live off the natural interest (i.e. renewable resources) and not deplete or degrade our natural capital (i.e. non-renewable resources). This approach to conservation is favoured by some people, but is criticized by others for extending a financial perspective onto human relationships with aspects of nature that are seen as intrinsically valuable (i.e. valued for their own sake).
Pearce et al. (1991) and Rees and Wackernagel (1994), among others, argue that to achieve sustainable development we need to maintain \'constant capital\'. One important difference between their two approaches is that Pearce et al. (1991) consider this capital to be both human-made and \'environmental assets\', whereas Rees and Wackernagel (1994, p. 367) argue that \'each generation should inherit an adequate stock of natural assets alone no less than the stock of such assets inherited by the previous generation\' (emphasis in original). They allow for the depletion of non-renewable natural resources to be compensated for through investment in renewable natural resources. The notion of \'natural capital\' being \'constant\' contains issues such as the location and costs of extraction of constant quantities of natural resources. Emel and Bridge (1995) note that one key feature of resource extraction, e.g. petroleum and gas, has been the marked shift in the northern hemisphere of production sites to colder regions at higher latitudes. In the case of oil and gas, this may also involve drilling in deeper seas. The ability to \'recover\' resources is increasingly dependent on greater technological and resource inputs, a process that is incompatible with some concepts of sustainable development.Â (PM)
References Emel, J. and Bridge, G. 1995: The earth as input: resources. In R. Johnston, P. Taylor and M. Watts, eds, Geographies of global change: remapping the world in the late twentieth century. Oxford and Cambridge, MA: Blackwell, 318-32.Â Jannson, A.-M. et al., eds, 1994: Investing in natural capital: the ecological economics approach to sustainability. Washington, D.C.: Island Press.Â MacNeill, J., Winsemius, P. and Yakushiji, T. 1991: Beyond interdependence: the meshing of the world\'s economy and the earth\'s ecology. New York: Oxford University Press.Â Pearce, D. et al., eds, 1991: Blueprint 2: greening the world economy. London: Earthscan.Â Rees, J. 1989: Natural resources, economy and society. In D. Gregory and R. Walford, eds, Horizons in human geography. Basingstoke and London: Macmillan, 364-94.Â Rees, W. and Wackernagel, M. 1994: Ecological footprints and appropriated carrying capacity: measuring the natural capital requirements of the human economy. In A.-M. Jannson et al., eds, Investing in natural capital: the ecological economics approach to sustainability. Washington, D.C.: Island Press, 362-90.Â Simon, J. 1994: More people, greater wealth, more resources, healthier environment. Economic Affairs 14 3: 22-9.Â Thorne, L. 1998: Kangaroos â€” the non issue. Society and Animals.Â Zimmerman, E. 1951:World resources and industries, rev. edn. New York: Harper and Row.
Suggested Reading Emel and Bridge (1995).Â Rees, J. 1991: Natural resources: allocation, economics and policy, 2nd edn. London and New York: Routledge.