Encyclopedia of Global Resources part 109 ppsx

ing seismic studies to decode the in - terior of the Earth; sonar for probing the ocean floor; and medicine using X rays and CAT scans. Remote sensing developed from several origins, both scientific and technological. Technologically, the telescope, invented in the1600’s, and photography, invented in the 1840’s, were significant advances in our abil- ity to remotely sense our environment. Then, the discovery of energy (frequencies) beyond the familiar visible light, in the 1860’s, by James Clerk Maxwell (1831-1879) demon- strated that our eyes were fairly lim- ited in gathering information that was available in the universe. Couple this with the aerial perspectives af- forded by ballooning (developed in the1780’s), flight (1900’s), and space travel (1950’s), and humanity’s concept of its environmentanduniversechangeddra- matically. Early Earth Resources Satellites Remote sensing as a stand-alone discipline had a par- allel development with the space race of the 1950’s and 1960’s. The advantages of a perspective from space became apparent with the National Aeronau- tics and Space Administration’s (NASA’s) April 1, 1960, launch of TIROS 1 (the Television Infrared Ob- servations Satellite), whose mission was to observe weather patterns. The advantages to meteorologists and weather forecasting were obvious, but there was other information to be garnered from these types of images. On July 23, 1972, the first of a series of satellites, Earth Resources Technology Satellite 1(ERTS-1), was launched with the specific mission of remotely sensing the Earth’s surface. The successof this mission en- couraged the launch of a succession of similar satellites with a different name: the Landsat series. This ongoing effort has given the scientific community decades of continuous coverage of the Earth’s surface. Passive vs. Active Sensors These satellites, and others from private companies and governments other than that of the United States, carry a variety of imaging scanners that look down on the Earth and transmit digital images to various ground stations. There are two types of sensors: active and passive. Active sensors that transmit to the target and collect bounces back via “radio detection and ranging” (radar) are examples.Passivesensors collect energy that is reflected from the target; forexample,a camera collects light. The majority of remote-sensing satellites utilize multiple passive sensors. These are designed to record reflected energy at different elec- tromagnetic frequencies, usually in both the visible and infrared portion of the spectrum. The advantage to combining different frequencies is that more con- trast can be discerned between targetsthatare similar. For example,the green leaf of a corn plantcan be dis- tinguished from the green leaf of a watermelon— from space. This discrimination is based on the reflected energy, or the object’s spectral signature. Spectral Signatures The key to interpreting a satellite image is in understanding the spectral signatures of the various objects in the image. Passive scanners receive the energy from the Sun that is reflected from the target (forexample, green plants). After it has passed through the atmosphere and interacted with the object, it passes through the atmosphere again and is collected by the satellite’s sensors. The atmosphere acts as a filter of some frequencies, and the object itself both absorbs and reflects frequencies. The signal (energy) that is reflected into space is different from the energy that left the Sun. This altered signal isspecifictotheobject and is its “spectral signature.” Nonliving objects— 1008 • Remote sensing Global Resources The U.S. Air Force Lockheed U-2 is a surveillance aircraft capable of accurate remote sensing. (United States Air Force) rocks, soil, water—tend to have more stable signa - tures, but plants can vary depending on species, age, and health. Thematic Mapping By identifying the spectral signature ofa target, allob- jects of the same signature can be mapped as the same, or the same theme. This is known as thematic mapping. For example, a cornfield will have a characteristic spectral signature that is different from an ad- jacent field of potatoes. Therefore, by identifying the spectral signature of the corn, all similar signatures within the image can be mapped as “corn.” These images are often color-coded to enhance discrimination between targets. This is known as “false color” imagery because the colors are assigned to enhance con- trast and are not descriptive of the object as seen in sunlight. As the data are recorded in a digital format, all of the pixels (picture elements) that compose the image can be counted and the extent or area of any signature can be measured. For example, an image or images of the Midwest can be collected, the spectral signature of a crop (such as corn or wheat), can be identified, and computer software can calculate the area of crop on the ground, its health, and its stage of development. This underscores the advantage of this technology. These types of thematic maps can be made over re- gional areas with computer speed. Geologists using the perspectiveof space canmap large geologic struc- tures, identify mineral deposits and potential fossil- fuel deposits, and inventory surface water resources. Further,inconjunctionwithland-useplanners,geologists can identify geologic hazards such as floodplains, sinkholes (karst topography), unstable slopes, and fault zones. Biologists and botanists use remotesensing data to map the diversity of plant communities and even to determine the health of ecosystems. Foresters can inventory timber resources and the health of forests. Farmers can map soil moisture or identify a frost-damaged orange tree, forexample,before stress becomes obvious to a trained observer on the ground. Land-use planners can map the various types of landuse(urban,suburban,andrural) and determine growth patterns of cities and communities over time. The Terra System The mission of NASA’s Terra system (formerly EOS AM-1), launched in December 18, 1999, is to research multidisciplinary problems directed primarily by re - searchers from the United States, Japan, and Canada. Terra’s broad goals are to investigate Earth systems; interactions among the atmosphere, hydrosphere, biosphere, and lithosphere; and changes in the global climate system. Terra has a design life of approxi- mately fifteen years (2000-2015). The five main sensors it carries are: • the Advanced Spaceborne Thermal Emissions and Reflection Radiometer (ASTER), which provides high-resolution imagery over fifteen spectral windows; it can develop thematic maps of surface tem- perature (reflectance) and elevation; • the Clouds and the Earth’s Radiant Energy System (CERES), which measures solar-reflected and Earth-emitted radiation from the Earth’s surface to the top of the atmosphere; • the Multi-Angle Imaging Spectroradiometer (MISR), which is composed of nine cameras using four different spectral windows; it primarily measures changes of atmospheric energy over time; • the Moderate-Resolution Imaging Spectroradi- ometer (MODIS), which captures imagery over thirty-six spectral windows and maps the entire Earth in a one- or two-day period; and • the Measurements of Pollution in the Troposphere (MOPITT), which (as its name implies) monitors pollution changes in the lower level of the atmosphere, which has the greatest impact on life. Perspective The science and technology of remote sensing are developing at a critical time for the citizens of the twenty- first century. Global population, approaching seven billion in 2009, was expected to be nine or ten billion by the middle of the twenty-first century. At the same time, a long-term trend toward increased socioeco- nomic status for nations such as China and India, com- bined with population, require ever-more resources to support an interlocking global economy. The abil- ity to explore, inventory, and manage natural resources to maintain this growth is greatly enhanced. However, remote sensing goes beyond the search for raw materialsto sustain humanity; it can help manage human resources as well. The data assists the understanding of the Earth’s changing climate, specifically rainfall patterns. This has a direct impact on where people can live and future migration patterns. By ob - serving the growth of cities and communities over time, these data can assist in the most efficient land- Global Resources Remote sensing • 1009 use planning. The “big picture” perspective from space coupled with the speed of computers to inter- pret this imagery is a timely and welcome tool for the twenty-first century. Richard C. Jones Further Reading Campbell, James B. Introduction to Remote Sensing. 4th ed. New York: Guilford Press, 2007. Jensen, John R. Remote Sensing of the Environment: An Earth Resource Perspective. 2d ed. Upper Saddle River, N.J.: Prentice-Hall, 2007. Ustin, Susan L., ed. Manual of Remote Sensing: Remote Sensing for Natural Resource Management and Environ- mental Monitoring. 3d ed. New York: Wiley, 2004. Web Sites Geoscience and Remote Sensing Society http://www.grss-ieee.org/ National Aeronautics and Space Administration Tutorial on Remote Sensing http://rst.gsfc.nasa.gov/ National Aeronautics and Space Administration Earth Observatory Remote Sensing: Introduction and History http://earthobservatory.nasa.gov/Features/ RemoteSensing/remote.php See also: Agriculture industry; Biosphere; Geo- graphic information systems; Geology; Hydrology and the hydrologic cycle; Land-use planning; Land- use regulation and control; Landsat satellites and satellite technologies; Lithosphere; Population growth; Resources for the Future; U.S. Geological Survey; Weather and resources. Renewable and nonrenewable resources Category: Environment, conservation, and resource management Nature provides numerous energy resources. Nonre - newable resources were the primary source of energy for the twentieth century. However, with the depletion of nonrenewables, interest in renewable forms of energy has generated increasing research and development of renewables. Background Nonrenewable resources cannot be readily replaced after consumption. A renewable resource is one that is continuously available, such as solar energy, or one that can be replaced within several decades, such as wood. Nonrenewable Energy Sources Nonrenewable resources may be subdivided into four categories: metals (such as copper and aluminum), industrial minerals (such as lime and soda ash), construction materials (sand and gravel), and energy resources (coal, oil, and uranium). Of the nonfuel substances, metals are most prone to depletion by overproduction, but recycling can prolong their use- ful lifetime almost indefinitely. Construction materials, although not readily recy- clable, are abundant and ubiquitous in the Earth’s crust, rendering them a virtually unlimited resource. Although less plentiful, the most widely used industrial minerals are unlikely to be depleted in the near future; on the scale of centuries, however, they are an endangered resource if current levels of production are maintained. It is probable that environmental concerns will reduce future production. The major forms of nonrenewable energy production are fossil fuel combustion (using oil and coal) and nuclear fission (using uranium). Of the total energy consumed by Americans, only 7 percent is from renewable resources, while 85 percent is from fossil fuels, predominantly oil. Coal was the first fossil fuel to be used extensively, and it remains the most abundant. Coalcan be burned directly or converted into petroleum or petroleum products, through the expenditure of additional energy. When used as fuel, coal creates many problems. Mines are environmentally destructive, and coal is the most difficult fossil fuel to transport. When coal is burned, vast quantities of sulfurcompounds(which form sulfuric acid in the atmosphere) are released, while thecarbon in the coal becomes carbon dioxide, a greenhouse gas believed to contribute to global warming. The carbon in coal also has many other valuable (nonpolluting) uses in the chemical in - dustry. Oil is the world’s major source of energy because it 1010 • Renewable and nonrenewable resources Global Resources is abundant andrelatively inexpensive.Its high rate of use will result in its depletion during the twenty-first century. When burned as gasoline in cars, it releases carbon dioxide; various dangerous air pollutants, such as carbon monoxide and nitrogen oxides; and uncombusted hydrocarbons (a major cause of photo- chemical smog). Natural gas, formed when organic materials decompose, is usuallyfoundwithpetroleum reservoirs. Its supply, rate of consumption,andproba- ble future are comparable to those of petroleum. It is widely used because it is relatively inexpensive, clean, and nonpolluting (although itdoesadd carbon to the atmosphere). Tar sands, principally found in Canada, are a low- grade source ofpetroleum thatis feasible to mineand process only when oil prices are relatively high. Two additional problems limit this source: About as much energy is required to extract usable oil as is created when it is combusted, and the process has raised environmental concerns. Oil shales, abundant in thewestern United States, appear theoret- ically to be a major source of future petroleum products. The amount of oil tied up in shale exceeds the remaining total world reserve of oil. To extract oil,however, the shale must be mined and heated by processes requiring large quantities of water in regions where water is scarce. Addi- tionally, the total energy required for extraction exceeds the energy created when the oil is burned. Nuclear reactors produce energy through con- trolled fission of uranium 235. No air pollution is produced, the mining operations are relatively small and safe, and the resource being consumed has no otherknownuse. On the otherhand, reactor technology is sophisticated and elaborate, and complicated devices are prone to break- downs. A reactor breakdown can have disastrous consequences if radioactive materials arereleased into the environment. Of equal or greater concern is how the by-products of nuclear power production—nuclear waste—should be disposed of over the long term. Renewable Energy Sources The most abundant renewable energy resource is solar energy, the source of most other renewables as well as the original source of fossil fuels. The supply is enormous andinexhaustible, but mostis wasted because it occurs in a dilute form that re - quires expensive hardware to concentrate. Also, it reaches Earth in its most dilute form during the win- ter, when it is most needed for heating. In cloudy regions it is not even available when demand for it is greatest. Like solar energy, wind represents a large and potentially inexhaustible source of energy. However, when wind energy is used to generate electricity, expensive collectors are required. Wind energy is not feasible everywhere, and even when feasible it is not always available. Power derived from moving water, such as that providedbyhydroelectricdams,makesan important contribution to the world’s energy supply. Many of the best sites have already been dammed, however, and development of a number of other sites is unwise because of ecological reasons or the sites’ scenic beauty. Global Resources Renewable and nonrenewable resources • 1011 A man hauls aluminum stoves through a street in Kabul, Afghanistan. Aluminum is a nonrenewable resource. (Zabi Tamanna/Xinhua/ Landov) Tidal energy utilizes the ebb and flow of tides to create electricity by trapping seawater at theextremes of high and low tide and releasing it through turbines. Although a potentially large energy source, it is economically feasible only where there are naturally high tides (4.5 meters or more) and where a narrow inlet encloses a large bay. Geothermal energy uses the heat from natural hot springs to create steam to power turbines, which are used to create electricity. Because the heat must be close to the surface, there are few known sites from which geothermal electrical energy can be extracted economically. Also, because pipelines must be run over many hectares to collect steam, the power-generating stations tend to be ugly and noisy. Vegetation (biomass) energy uses plants or animal products derived from plants as a source of fuel. This source includes wood, organic wastes, ethanol, and methane gas from biodigestion. This type of renewable resource is renewable only if harvesting is con- trolled and if resources exist to cultivate the source. Thus, trees must be given sufficient time to mature, and corn must be cultivated before ethanol can be produced. Although vegetation has a long history as a source of fuel, efficient and sustainable techniques have yet to be introduced. George R. Plitnik Further Reading Boyle, Godfrey, ed. Renewable Energy. 2d ed. New York: Oxford University Press in association with the Open University, 2004. Cassedy, Edward S., and Peter Z. Grossman. Introduc- tion to Energy: Resources, Technology,andSociety.2ded. New York: Cambridge University Press, 1998. Evans, Robert L. Fueling Our Future: An Introduction to Sustainable Energy. Cambridge, England: Cambridge University Press, 2007. González, Pablo Rafael. Running Out: How Global Shortages Change the Economic Paradigm. New York: Algora, 2006. Greiner, Alfred, and Willi Semmler. The Global Envi- ronment, Natural Resources, and Economic Growth. New York: Oxford University Press, 2008. Hinrichs, Roger A., and Merlin Kleinbach. Energy: Its Use and the Environment. 4th ed. Belmont, Calif.: Thomson, Brooks/Cole, 2006. Kozlowski, Ryszard, Gennady Zaikov, and Frank Pudel, eds. Renewable Resources: Obtaining, Processing, and Applying. Hauppauge, N.Y.: Nova Science, 2009. Kruger, Paul. Alternative Energy Resources: The Quest for Sustainable Energy. Hoboken, N.J.: John Wiley & Sons, 2006. Pimentel, David, ed. Biofuels, Solar, and Wind as Renew- able Energy Systems: Benefits and Risks. New York: Springer, 2008. Twidell, John, and Tony Weir. Renewable Energy Re- sources. 2d ed. New York: Taylor & Francis, 2006. See also: Coal; Ethanol; Geothermal and hydrother- mal energy; Hazardous waste disposal; Hydroenergy; Nuclear energy; Nuclear waste and its disposal; Oil and natural gas distribution; Oil shale and tar sands; Solar energy; Tidal energy; Wind energy; Wood and charcoal as fuel resources. Reserve Mining controversy Category: Historical events and movements Date: 1968-1980 The Reserve Mining Company was successfully prose- cuted for disposing of hazardous waste from its taconite mining into Lake Superior. Definition The Reserve Mining controversy involved the discharge of taconite tailings into Lake Superior by the Reserve Mining Company. The discharge created concern about health and environmental impacts and led to litigation. The courts ruled against Reserve Mining. Overview The Reserve Mining Company was established in 1939 to mine taconite ores at Babbitt, Minnesota, on the Mesabi Iron Range. Taconite is a low-grade iron ore that requires a processing facility to concentrate and pelletize the ore before it can be used. The company decided that the best way of disposing of the re- sulting tailings (waste) was by discharging them into Lake Superior. The selected site was located at Silver Bay on the LakeSuperiorshorenearDuluth.Thenec- essary permits were granted in December, 1947, and operations began in 1955. Within ten years, annual pellet output capacity at the processing plant had reached 9.7 million metric tons, with a water volume of 1.9 million liters per minute. 1012 • Reserve Mining controversy Global Resources There had been little concern about the tailings discharge into Lake Superior at the permit hearings or during the initial yearsofoperationexceptby sport fishermen. This situation changed when the Stod- dard report by the Department of the Interior and state agencies in1968 concluded thatReserve Mining was polluting Lake Superior in violation of its permits. The report noted concerns about“green” water,trace metals, fish mortality, asbestos-like fibers, and lake eutrophication being associated with the discharge. This report was strongly rejected by Reserve Mining. There was growing concern about the tailings discharge by the public as well, which led to citizen groups fighting against it. An unsuccessful series of conferences was held to try to resolve the issues. The Environmental Protection Agency took over for the Department of the Interior in 1970, and a lawsuit was filed in federal court in 1972 to stop the discharge. As the trial began in 1973, a new finding changed the entire focus of the environmental concern. It was determined that the asbestos-like fibers in the ore were present in the drinking water of nearby communities such asDuluth, creating a concern about theef- fects on human health. Duluth was forced to build a filtration system that cost $6.9 million. The initial court judgmentin 1974 ruled that thedischarge must stop. A stay was given by the appeals court while an ac- ceptable on-land site was to be located and developed. After the first judge was removed by the appeals court for bias against Reserve Mining, the secondjudgealso found against Reserve Mining. Reserve Mining and its owners, Armco and Republic, were required to pay more than $1 millioninfinesand to pay for thecostof filtering Duluth’s drinking water before the filtration plant was ready. With the approval of an on-land disposal site, discharge into Lake Superior ended in 1980. Gary A. Campbell See also: Environmental law in the United States; Environmental Protection Agency; Eutrophication; Lakes; Mining wastes and mine reclamation; Water pollution and water pollution control. Residual mineral deposits Categories: Geological processes and formations; mineral and other nonliving resources Residual mineral deposits are formed by chemical weathering processes that dissolve and remove undesired constituents of rocks, leaving behind valuable deposits of insoluble minerals. Examples include bauxite and residual iron,manganese,nickel, phosphate, and clays. Background Residual mineral deposits are the result of residual concentration, a process whereby weathering removes undesired constituents from rock to leave behind a concentration of valuable minerals. This residue, which is able to withstand further chemical weathering, can accumulate to form commercially significant deposits. Important depositsofiron, aluminum, manganese, nickel, phosphate, clays, and other economic minerals have been formed by residual concentration. Formation Residual mineral deposits form from rocks that contain valuable minerals that are either insoluble or al- ter to form insoluble compounds upon weathering; the undesired components of the rock are relatively soluble. As the rocks undergo chemical weathering, the unwanted materials are gradually dissolved and carried away. If the outcrop surface has low relief (so that physical weatheringprocesses cannotremove significant amounts of the insoluble residues) and if the terrain remains stable over a period of time long enough to allow the residuestoaccumulate,aresidual deposit can form. Because chemical weathering is a slow process and the materials being removed (such as calcite, feldspar, clay, and quartz) are often only slightly soluble, it may take millions of years for a residual accumulation to develop that is of sufficient pu- rity and volume to be of commercial importance. Warm, humid conditions are most conducive to the formation of residual deposits. While ores can develop through residual concentration in a temperate climate, tropical and subtropical environments host a greater variety of residual deposits. Characteristics Residual mineral deposits frequently occur in regions where the climate is or was humid, subtropical, or tropical. They form in relatively level depositional environments, where physical weathering processes ex - ert a minimal influence. The presence of iron oxides concentrated in the weathering zone typically imparts Global Resources Residual mineral deposits • 1013 a deep red or brown color todepositsformed by resid - ual concentration. The removal of soluble material generally leaves the deposits with a porous texture or with a consistency resembling that of loose soil.Resid- ual deposits are usually underlain by the rock from which they were derived. A particular form of residual deposit, laterite, is characteristic of the hot, humid tropics. Laterite is a highly weathered red soil or surface material that is rich in iron and aluminum oxides and hydroxides. A lateritic deposit formsafterintensechemical weathering has leachedtheparent rock of most ofits silica. Al- ternating wet and dry seasons, high drainage rates, and minimal physical erosion all contribute tolaterite formation. Residual Iron Iron is present in most rocks, and residual iron deposits, including laterites, are widely distributed within nonglaciated regions. Residual concentration of iron is particularly likely where limestone or extremely iron-rich silicate rocks are exposed to warm, humid conditions. Significant residual-iron deposits include those foundin the southeastern United States, Brazil, Venezuela, the West Indies, southern Europe, Africa, and India. Residual Aluminum (Bauxite) Bauxite, the chief ore of aluminum, is a lateritic deposit formed by residual concentration in tropical or subtropical regions. A mixture of several hydrated aluminum oxides, bauxite deposits result from the de- composition of aluminum silicate rocks that are high in aluminum silicates and low in iron and free quartz. Warm rain water, groundwater, oxygen, carbon dioxide, and humicacidinteract to break down theparent rock. The French deposits at Baux, from which bauxite derives its name, formed from limestones or clays in limestones. In Arkansas, Brazil, and French Gui- ana, the source rock is nepheline syenite, an intrusive igneous rock composed largely of alkali feldspars and feldspathoids (minerals similar to feldspars but containing less silica). Deposits in India formed from ba- salt; those in Georgia, Alabama, Jamaica, and Guyana derived from clays; those in Ghana originated from clay shales and other aluminum-rich rocks; and those in Thailand derived from clay alluvium.Mostbauxites were formed between the middle Cretaceous and middle Eocene times. Residual Manganese, Nickel, Phosphate, and Clays Residual deposits of manganese form under conditions similar to those that produce residual iron. Re- sidual manganese deposits are commonly derived from crystalline schists, limestones previously enriched with manganese minerals, or primary deposits of manganese minerals. Important residual manganese deposits include those found in Brazil, Romania, Mo- rocco, Egypt, Ghana, India, Japan, Malaysia, and the Philippines. Under tropical and subtropical conditions, some low-silica igneous rocks decompose to produce hy- drous silicates of nickel and magnesium. Nickel laterite derived from serpentinized peridotite is found in New Caledonia, Cuba, Brazil, and Venezuela. In Florida, the leading phosphate-producingstate,residual concentrations of“land-pebblephosphate” occur. Weathering and solution of phosphate-containing Mio- cene limestones left behind this loose, easily mined residue of calcium phosphate pebbles and boulders. In a humid, temperate climate, the chemical weathering of aluminum-bearing rocks produces clay. Weathering does not proceed far enough to remove silica and produce a laterite, as in tropical regions; in- stead, the aluminum and silica combine to form hy- drous aluminum silicates—clay minerals. Crystalline rocks that contain abundant feldspars and little iron, such as granite and gneiss, are the primary source rocks for clayformation. High-graderesidual clays occur in the southern and western United States, En- gland, France, Germany, eastern Europe, and China. Other Residual Deposits Other products of residual concentration include trip- oli, an earthymaterial composed almost entirelyofsil- ica and derived from weathered chert or silica-rich limestone; the residual kyanite deposits of India and the eastern United States; the residual barite deposits of Missouri; the nodularzincores ofVirginia and Ten- nessee; and the residual gold accumulations in the United States, Brazil, Madagascar, and Australia. Karen N. Kähler Further Reading Chamley, Hervé. Clay Sedimentology. New York: Springer, 1989. Evans, Anthony M. Ore Geology and Industrial Minerals: An Introduction.3d ed. Boston: Blackwell Scientific, 1993. 1014 • Residual mineral deposits Global Resources Guilbert, John M., and Charles F. Park, Jr. The Geology of Ore Deposits. Long Grove,Ill.:WavelandPress,2007. Jensen, Mead L., and Alan M.Bateman. Economic Min- eral Deposits. 3d ed. New York: Wiley, 1979. McFarlane, M. J.LateriteandLandscape.NewYork:Aca- demic Press, 1976. Misra, Kula C. Understanding Mineral Deposits. Boston: Kluwer Academic, 2000. Robb, Laurence. Introduction to Ore-Forming Processes. Malden, Mass.: Blackwell, 2005. Valeton, Ida. Bauxites. New York: Elsevier, 1972. See also: Aluminum; Clays;Iron; Manganese;Nickel; Phosphate; Secondary enrichment of mineral deposits; Silicates; Weathering. Resource accounting Category: Social, economic, and political issues Resource accounting (RA), which is also called environmental resource accounting or green accounting, refers to accounting systems designed to revise or sup- plement the conventional system of national accounts (SNA), which is used by national governments and by the United Nations. The conventional system does not consider resource depletion or environmental degradation. Background In traditional economics, the system of national accounts (SNA) measures both a country’s output of goods and services and the country’s income. It is used asan indicator ofnational economic activity and economic performance. However, the SNA does not fully incorporate natural resources in measuring the national product anddoes not take account of the depletion of natural resources or the degradation of the environment in measuring economic performance. Resource accounting (RA) revises or supplements SNA calculations to correct these omissions. There is no standardized system of resource accounting. A wide variety of accounting systems have been proposed by economists, depending in part on the purposes to be served by the accounts and the methods used for measuring the relevant variables. Some systems are designed to revise the conventional SNA, but in most cases the authors propose supple - ments to the SNA. Resource accounting has been used for analyzing the conditions for sustainable development, for shaping national economic policies, and for measuring environmental and economic performance. The United Nations and the World Bank have published analytical studies on RA, and national accounts using RA models have been prepared for a number of countries, including Indonesia, Papua New Guinea, and Mexico. In his April, 1993, Earth Day speech, President BillClintoncalled on the Bureau of Economic Analysis toproduce “Green GDP [gross do- mestic product] measures that would incorporate changes in the natural environment into the calcula- tion of national income and wealth.” The U.S. Depart- ment of Commerce has published articles on RA and has prepared RA satellite accounts for use as supplements to the department’s SNA. RA Adjustments to SNA Resource accounting provides for the following types of revisions of, or supplements to, the existing system of national accounts estimates. First, account can be taken of the changes in physical amounts of natural resources that result from human activities. Natural resources are regarded as capital assets subject to depletion and degradation in a manner analogous to the depreciation of assets such as buildings and ma- chinery. In the SNA, depreciation of manmade capital is deducted from the GDP in calculating the net national product (NNP), but there is no deduction for depletion ordegradation of natural resource capital. Supporters of RA argue that the failure to deduct natural resource depletion and degradation in calculating net national product or national income is im- proper because output from natural resource depletion is no longer available for consumption after the resources are exhausted. This concept is in accor- dance with the economic principle that true income cannot include capital consumption. In RA case studies, soil erosion, deforestation, and the depletion of mineral reserves are considered as major reductions in the GDP. Some models also include the deteriora- tion of water supplies and air pollution. Second, account can be taken of the final services provided by natural resources and the environment, such as aesthetic benefits from wilderness areas and biological diversity, both of which contribute to the quality of humanlife. If these services are impaired by human production and consumption, national in - come and product accounts are adjusted for the re - Global Resources Resource accounting • 1015 duction of these services. For example, when a dam destroys the scenic value of acanyon, the reduction in the amenities provided by the canyon is regarded as a cost to be deducted from the output attributed to the construction of the dam. Third, SNA expenditures for environmental protection, such as pollution abatement,canberegarded as costs of production rather than being included in national income. The recycling of waste material and the cleaning ofwaste dumps are alsoregarded as costs of production. Analytical Problems Full accounting by RA systems for the adjustments listed above involvesanumber of analytical problems. For example, all RAsystemsadjustfor mineral reserve depletion, but economistsdo not agree on theproper method of calculating depletion. One simple method is to multiply annual mineral output by the average price of the mineral products and then deduct the cost of labor and capital required for extraction and exploration. However, this method does not take into consideration the net income produced by the mineral, since theentire outputis attributed to depletion. A more accurate variation of this approach is to esti- mate the reduction in the capital value of a mineral between two periods during which extraction has taken place. The problem here is that capital values can change because of a change in the price of the mineral or the cost of producing it, or because of a change in the volume of mineral reserves not related to extraction. An alternative method, called the user-cost method, divides annual revenue from the sale of the minerals (after deducting extraction costs) into income and depletion, with depletion determined as the amount necessary to create a fund sufficienttoyieldanannual amount equal to the income portion, beginning after the mineral reserve is exhausted. Both methods have advantages and disadvantages, and both have been used for calculating the net national products of indi- vidual countries. Measuring Sustainable Growth An important use of RA is to determine whether a developing country is following a path of sustainable development or is depleting its natural resource capital—including its minerals, forests, and soil—under conditions that threaten theeconomy’s abilityto main - tain its current level of consumption. If a country saves and invests in other industries an amount equal to the value of the depletion of its natural resource capital, mineral exhaustion may not be accompanied by a decline in economic growth. RA also provides a more accurate measure of acountry’s growth rate, because without taking account of natural resource depletion and degradation, the growth rate measured by SNA may overstate the rate that the country can sustain. Raymond F. Mikesell Further Reading Ahmad, Yusuf J., Salah El Serafy, and Ernst Lutz, eds. Environmental Accounting for Sustainable Develop- ment. Washington, D.C.: World Bank, 1989. Bartelmus, Peter, and Eberhard K. Seifert, eds. Green Accounting. Burlington, Vt.: Ashgate, 2003. Hecht, Joy E. National Environmental Accounting: Bridging the Gap Between Ecology and Economy. Wash- ington, D.C.: Resources for the Future, 2005. Lange, Glenn-Marie. “Environmental and Resource Accounting.” In Handbook of Sustainable Develop- ment, edited by Giles Atkinson, Simon Dietz, and Eric Neumayer. Northampton, Mass.: Edward Elgar, 2007. Lutz, Ernst,ed. Toward ImprovedAccountingfor the Envi- ronment. Washington, D.C.: World Bank, 1993. Mikesell, Raymond F. Economic Development and the En- vironment: A Comparison of Sustainable Development with Conventional Development Economics. New York: Mansell, 1992. Perrings, Charles, and Jeffrey R. Vincent, eds. Natural Resource Accounting and Economic Development: The- ory and Practice. Northhampton, Mass.: Edward Elgar, 2003. Repetto, Robert, et al. Wasting Assets: Natural Resources in the National Income Accounts. Washington, D.C.: World Resources Institute, 1989. Rogers, Peter P. “Natural Resource Accounting.” In An Introduction to Sustainable Development, edited by Stephen J. Banta, David Sheniak, and Anita Feleo. Cambridge, Mass.: Continuing Education Division, Harvard University, 2006. See also: Capitalism and resource exploitation; De- forestation; Developing countries; Ecosystem services; Energy economics; Environmental degradation, resource exploitation and; Health, resource exploita - tion and; Renewable and nonrenewable resources; United Nations Environment Programme. 1016 • Resource accounting Global Resources Resource Conservation and Recovery Act Categories: Laws and conventions; government and resources Date: Passed October 21, 1976 The Resource Conservation and Recovery Act of 1976 (RCRA) is a comprehensive U.S. environmental law that regulates nonhazardous solid waste and hazardous waste. It encourages recycling and reuse andman- dates that hazardous waste be managed in an environmentally responsible manner from the time it is generated until it is disposed of. Background After World War II, the United States experienced rapid economic and industrial expansion. With this growth came a significant increase in the generation and accumulation ofwastes, both hazardous and nonhazardous. As waste management practices failed to keep pace with waste production, much of the waste entered the environment, where it posed a threat to ecosystems and human health. In 1965, Congress passed the Solid Waste Disposal Act (SWDA), which set safety standards for landfills and established a framework for managing trash disposal. Over the following decade, however, waste disposal problems continued to mount. The amount of trash generated by individuals rose, as did the quan- tity of toxic by-products produced by the manufacture of synthetic chemicals. A 1970 amendment, the Re- source Recovery Act,sought to bring the problem under control by setting national disposal criteria for hazardous waste, establishing guidelines for sanitary landfill and incineration facility operation, and en- couraging programs for reclamation of materials and energy from solid waste. By the mid-1970’s, it was clear that the waste management provisions of the amended SWDA remained insufficient to meet the challenges posed by the stag- gering quantities of solid and hazardous waste that municipalities and industries across the nation were generating. Congress addressed SWDA’s deficiencies with the October 21, 1976, passage of a more comprehensive amendment, known as RCRA. RCRA was so thorough an overhaul of SWDA that amendments to SWDA passed after 1976 aregenerally regarded as part of RCRA. Among the more signifi - cant of these amendments are the Medical Waste Tracking Act of 1988 (MWTA), the Hazardous and Solid Waste Amendments of 1984 (HSWA), the Fed- eral Facilities Compliance Act of 1992 (FFCA), and the Land Disposal Program Flexibility Act of 1996 (LDPFA). MWTA followed highly publicized incidents in 1987, in which syringes and other medical waste washed up on publicbeachesin the Northeast. HSWA passed in response to public concern regarding hazardous waste disposal in substandard incinerators and landfills. FFCA was enacted in theearly post-Cold War years to require RCRA compliance from Department of Defense and Department of Energy sites and other federal facilities that had previously claimed sovereign immunity from environmental regulations. LDPFA, designed to eliminate regulatory redundancy and reduce compliance costs associated with the disposal of certain low-risk wastes, was part of the Reinventing Environmental Regulation initiative, a commonsense legal-reform effort during Bill Clinton’s presidency. Provisions RCRA is a groundbreaking environmental law in that it takes a “cradle-to-grave” approach to pollution control. It seeks not only to mitigate pollutant emissions but also to minimize how much pollution is generated in the first place. RCRA requires that, once generated, hazardous wastes be managed, tracked, and ultimately disposed of, all in an environmentally responsible manner. RCRA encourages measures such as source reduction, recycling, and conservation of energy and natural resources. The act sets forth statutory and regulatory requirements and liability for owners and operators of facilities that fail to meet its requirements. The U.S. Environmental Protection Agency (EPA) Office ofResource Conservation and Recovery (known prior to2009 as the Office of Solid Waste) has primary responsibility for implementing RCRA. RCRA provisions address three interrelated waste- management concerns: nonhazardous solid waste (Subtitle D), hazardous solid waste (Subtitle C), and underground storage tanks (Subtitle I). A fourth program focusing on medical-waste management, de- scribed in Subtitle J, is no longer in effect. Subtitle D of RCRA provides a regulatory framework for the nation’s solid-waste management. It pro- hibits open dumping of solid wastes and establishes minimum standards for landfill location, operation (including dailycover requirements), design (includ - ing liners and leachate collection systems), ground - Global Resources Resource Conservation and Recovery Act • 1017 . supply. Many of the best sites have already been dammed, however, and development of a number of other sites is unwise because of ecological reasons or the sites’ scenic beauty. Global Resources. following types of revisions of, or supplements to, the existing system of national accounts estimates. First, account can be taken of the changes in physical amounts of natural resources that. is the world’s major source of energy because it 1010 • Renewable and nonrenewable resources Global Resources is abundant andrelatively inexpensive.Its high rate of use will result in its depletion