1	Chapter 14 Resource Issues
2	First World Pollution People have always transformed Earth’s land, water, and air for their benefit. But human actions in recent years have gone far beyond the impact of the past. The magnitude of transformations is disproportionately shared by North Americans; with only one-twentieth of Earth’s population, North Americans consume one-fourth of the world’s energy and generate one-fourth of many pollutants.
3	Third World Issues Elsewhere in the world, two billion people live without clean water or sewers. One billion live in cities with unsafe sulfur dioxide levels. Future generations will pay the price if we continue to mismanage Earth’s resources. Our carelessness has already led to unsafe drinking water and toxic air in some places. Our inefficiency could lead to shortages of food. Humans once believed Earth’s resources to be infinite, or at least so vast that human actions could never harm or deplete them. But warnings from scientists, geographers, and governments are making clear that resources are indeed a problem.
4	Key Issues for Chapter 14 Key Issues This Chapter 1. Why are resources being depleted? 2. Why are resources being polluted? 3. Why are resources reusable? 4. Why can resources be conserved?
5	Resource Issues Geographers study the troubled relationship between human actions and the physical environment in which we live. A resource is a substance in the environment that is useful to people, is economically and technologically feasible to access, and is socially acceptable to use. Resources include food, water, soil, plants, animals, and minerals. The problem is that most resources are limited, and Earth has a tremendous number of consumers. Geographers observe two major misuses of resources: We deplete scarce resources—especially petroleum, natural gas, and coal... We destroy resources through pollution of air, water, and soil. Nowhere is the globalization trend more pronounced than in the study of resources. Global uniformity in cultural preferences means that people in different places value similar natural resources, although not everyone has the same access to them. In a global environment, all places are connected, so the misuse of a resource in one place affects the well-being of people everywhere.
6	Resource Depletion Energy resources Fossil fuel supply Distribution of fossil fuels World petroleum control Nonrenewable substitutes Mineral resources Nonmetallic minerals Metallic minerals
7	Value of Resources Natural resources have little value in and of themselves. Their value derives from their usefulness to humans, especially in production. Two kinds of natural resources are especially valuable to humans: minerals and energy resources. More developed countries want to preserve current standards of living, and less developed countries are struggling to attain a better standard. All this demands tremendous energy resources, so as we deplete our current sources of energy, we must develop alternative ones.
8	Energy Resources Historically, people relied on power supplied by themselves or by animals, known as animate power. Ever since the Industrial Revolution began in the late 1700s, humans have expanded their use of inanimate power, generated from machines. Humans have found the technology to harness the great potential energy stored in resources such as coal, oil, gas, and uranium. Three of Earth’s substances provide five-sixths of the world’s energy: oil, natural gas, and coal. In MDCs the remainder comes primarily from nuclear, solar, hydroelectric, and geothermal power. Burning wood provides much of the remaining energy in less developed societies. Historically, the most important energy source worldwide was biomass fuel, such as wood, plant material, and animal waste.
9	Energy Resources Continued Coal supplanted wood as the leading energy source in the late 1800s in North America and Western Europe. Petroleum was. . . not an important resource until the diffusion of automobiles. Natural gas was originally burned off as a waste product of oil drilling but now heats millions of homes. Energy is used in three principal places: businesses, homes, and transportation. For U.S. businesses the main energy resource is coal. Some businesses directly burn coal. Others rely on electricity, mostly generated at coal-burning power plants. At home, energy is used primarily for heating of living space and water. Natural gas is the most common source, followed by petroleum (heating oil and kerosene). Almost all transportation systems operate on petroleum products. Only subways, streetcars, and some trains run on coal-generated electricity. Petroleum, natural gas, and coal are known as fossil fuels. A fossil fuel is the residue of plants and animals that became buried millions of years ago.
10	Finiteness of Fossil Fuels Two characteristics of fossil fuels cause great concern for the future: The supply of fossil fuels is finite; Fossil fuels are distributed unevenly around the globe. To understand Earth’s resources, we distinguish between those that are renewable and those that are not: Renewable energy is replaced continually, or at least within a human lifespan; Nonrenewable energy forms so slowly that. . . it cannot be renewed. The world faces an energy problem in part because we are rapidly depleting the remaining supply of the three fossil fuels, especially petroleum. We can use other resources for heat, fuel, and manufacturing, but they are likely to be more expensive and less convenient to use than fossil fuels.
11	Remaining Supply of Fossil Fuels How much of the fossil-fuel supply remains? Despite the critical importance of this question for the future, no one can answer it precisely. The amount of energy remaining in deposits that have been discovered is called a proven reserve. Proven reserves can be measured with reasonable accuracy. The energy in undiscovered deposits that are thought to exist is a potential reserve. The World Energy Council estimates potential oil reserves of about 500 billion barrels, with the largest fields thought to lie beneath the South China Sea and northwestern China.
12	Petroleum Reserves
13	Coal Reserves
14	Natural Gas Reserves
15	Extraction of Remaining Reserves When it was first exploited, petroleum “gushed” from wells. Coal was quarried in open pits. But now extraction is harder. The largest, most accessible deposits of (fossil fuels) already have been exploited. Newly discovered reserves generally are smaller and more remote. Unconventional sources of petroleum and natural gas are being studied and developed, such as oil shale and tar sandstones. They are called unconventional.. . because we do not currently have economically feasible, environmentally sound technology to extract them. Utah, Wyoming, and Colorado contain more than 10 times the petroleum reserves of Saudi Arabia, but as oil shale.
16	Uneven Distribution of Fossil Fuels Geographers observe two important inequalities in the global distribution of fossil fuels: Some regions have abundant reserves, whereas others have little; Consumption of fossil fuels is much higher in some regions than in others. Unequal possession and consumption of fossil fuels have been major sources of global instability in the world.
17	Location of Reserves Some regions have abundant reserves of fossil fuels, but other regions have little. This partly reflects how fossil fuels form. Coal forms in tropical locations. The tropical swamps of 250 million years ago have relocated to the mid latitudes (with) the slow movement of Earth’s drifting continents. Oil and natural gas formed from sediment deposited on the seafloor. Some, reserves still lie beneath seas, but other reserves are located beneath land that had been under water millions of years ago. Five Middle Eastern countries have two-thirds of the world’s oil reserves. Venezuela and Mexico have the most extensive proven reserves in the Western Hemisphere.
18	Petroleum Production
19	Natural Gas Production
20	Per Capita Energy Consumption
21	World Energy Consumption
22	The Future of Fossil Fuels The global pattern of fossil-fuel consumption—like production—will shift in the twenty-first century. More developed countries, with about one-fourth of the world’s population, currently consume about three-fourths of the world’s energy. The sharp regional difference in energy consumption has two geographic consequences for the future: As they promote development and cope with high population growth, LDCs will consume much more energy. The share of world energy consumed by LDCs will increase from about 25 percent today to 40 percent by 2010 and 60 percent by 2020. MDCs must import fossil fuels from LDCs. Because of development and population growth in LDCs, the more developed countries will face greater competition in obtaining the world’s remaining supplies of fossil fuels.
23	Control of World Petroleum The sharpest conflicts over energy will be centered on the world’s limited proven reserves of petroleum. The MDCs import most of their petroleum from the Middle East, where most of the world’s proven reserves are concentrated. Both U.S. and Western European transnational companies originally exploited Middle Eastern petroleum fields and sold the petroleum at a low price to consumers in MDCs.
24	OPEC Policies during the 1970s Several LDCs possessing substantial petroleum reserves created the Organization of Petroleum Exporting Countries (OPEC) in 1960. OPEC’s Arab members were angry at North American and Western European countries for supporting Israel during that nation’s 1973 war with the Arab states of Egypt, Jordan, and Syria. So during the winter of 1973—74, they flexed their new economic muscle with a boycott—Arab OPEC states refused to sell petroleum to the nations that had supported Israel. Soon gasoline supplies dwindled in MDCs. Each U.S. gasoline station was rationed a small quantity of fuel. European countries took more drastic action—the Netherlands, for example, banned all but emergency motor vehicle travel on Sundays. OPEC lifled the boycott in 1974 but raised petroleum prices from $3 per barrel to more than $35 by 1981.
25	U.S. Energy Consumption 1850–2000
26	U.S. Oil Imports, 1973 and 2003
27	Since The Oil Crisis of the 70’s The United States reduced its dependency on imported oil in the immediate wake of the 1970s shocks, and the share of imports from OPEC countries declined from two-thirds in 1973 to one-half in 1999. But oil imports climbed rapidly in the late twentieth century, from 1.2 billion barrels in 1985 to 3.2 billion barrels in 1999. At some point extracting the remaining petroleum reserves will prove so expensive and environmentally damaging that use of alternative energy sources will accelerate, and dependency on petroleum will diminish. The issues for the world are whether dwindling petroleum reserves are handled wisely and other energy sources are substituted peacefully. Given the massive growth in LDCs more developed countries may have little influence.
28	Nonrenewable Substitutes for Petroleum As petroleum supplies dwindle, the two other principal fossil fuels—natural gas and coal—are short- run substitutes. Nuclear energy also figures prominently in short-term energy planning.
29	Natural Gas Natural gas is cheaper to burn and is less polluting than petroleum and coal, and in the twentieth century supplies were less subject to disruptions for political reasons. Consequently, world natural gas consumption increased by two-thirds between 1980 and 2000, whereas petroleum consumption increased by only one-fifth. At the current rate of use, the world’s proven reserves of about 140 trillion cubic meters of natural gas will last for about 80 years. Although the United States is a major producer of natural gas, proven reserves are limited. Within North America, pipelines carry natural gas to industrial and residential users. It is difficult to ship natural gas across oceans.
30	Coal Production
31	Issues with Coal Uncontrolled burning of coal releases several pollutants. The U.S. Clean Air Act now requires utilities to use better-quality coal or to install “scrubbers” on smokestacks. Historically, mining was an especially dangerous occupation. Strictly enforced U.S. mine safety laws, automation of mining, and a smaller workforce have made the American coal industry much safer. Annual U.S. mine mortality now is below 100. But that figure could rise if mining operations expanded. Underground mining may pollute water and (cause) subsidence or sinking of the ground. Surface mining can cause soil erosion. In the United States the mining industry is highly regulated, and most companies today have a good record. But, practices in the past have left a legacy of environmental damage. Coal must be shipped long distances, because most of the factories and power plants using it are far from the coalfields. Ironically, the principal methods of transporting coal—barge, rail, or truck—are all powered by petroleum.
32	Nuclear Power Production
33	Nuclear Power in the U.S.
34	Nuclear - Potential Accidents A nuclear power plant produces electricity from energy released by splitting uranium atoms in a controlled environment, a process called fission. Elaborate safety precautions are taken to prevent nuclear fuel from leaking from a power plant. Nuclear power plants cannot explode, like a nuclear bomb. However, it is possible to have a runaway reaction, which overheats the reactor, causing a meltdown, possible steam explosions, and scattering of radioactive material into the atmosphere. This happened in 1986 at Chernobyl in the north of Ukraine, near the Belarus border. The impact of the Chernobyl accident extended through Europe. Half of the eventual victims may be residents of European countries other than Ukraine and Belarus.
35	Nuclear - Radioactive Waste When nuclear fuel fissions, the waste is highly radioactive and lethal and remains so for many years. Plutonium can be harvested from it for making nuclear weapons. No one has yet devised permanent storage for radioactive waste. It must be isolated for several thousand years. The United States is Earth’s third-largest country in land area, yet it has failed to find a suitable underground storage site because of worry about groundwater contamination. The time required for radioactive waste to decay to a safe level is far longer than any country or civilization has existed.
36	Nuclear - Bomb Material Nuclear power has been used in warfare twice, in August 1945, when the United States dropped an atomic bomb on first Hiroshima and then Nagasaki, Japan. No government has (since) dared to use them in a war, because leaders have recognized that a full-scale nuclear conflict could terminate human civilization. But the black market could provide terrorists with enough plutonium to construct nuclear weapons.
37	Nuclear - Limited Uranium Reserves Like fossil fuels, proven uranium reserves are limited—about 60 years at current rates of use. Uranium ore naturally contains only 0.7 percent U-235, and a greater concentration is needed for power generation. Proven uranium reserves could be depleted in three more decades. A breeder reactor turns uranium into a renewable resource by generating plutonium, also a nuclear fuel. However, plutonium is more lethal than uranium. It is also easier to fashion into a bomb. Because of these risks, few breeder reactors have been built, and none are in the United States.
38	Nuclear – Cost Nuclear power plants cost several billion dollars to build, primarily because of elaborate safety measures. Uranium is mined in one place, refined in another, and used in still another. The cost of generating electricity is much higher from nuclear plants than from coal-burning plants. The future of nuclear power has been seriously hurt by the combination of high risk and cost. Most countries in North America and Western Europe have curtailed construction of new plants. Nuclear power will decline in other countries as older nuclear plants are closed and not replaced.
39	Elements in the Earth’s Crust
40	Nonmetallic Minerals Building stones, including large stones, coarse gravel, and fine sand, account for 90 percent of nonmetallic mineral extraction. Nonmetallic minerals are also used for fertilizer. Important nonmetallic mineral sources of fertilizers include phosphorus, potassium, calcium, and sulfur. All four are abundant elements in nature with wide distributions. However, mining is highly clustered where the minerals are most easily and cheaply extracted. Although only a small percentage of nonmetallic minerals in weight, gemstones are valued especially highly for their color and brilliance when cut and polished. Diamonds are especially useful in manufacturing.
41	Metallic Minerals Metallic minerals have properties that are especially valuable for fashioning machinery, vehicles, and other essential components of an industrialized society. Many metals are also capable of combining with other metals to form alloys with yet other distinctive properties. Metals are known as ferrous or nonferrous: Ferrous is derived from the Latin word for iron; Nonferrous metals are those utilized to make products other than iron and steel. World supply of most metals is high, including the most widely used ferrous metal (iron) and the most widely used nonferrous metal (aluminum). However, reserves of some metals are low, posing a challenge to manufacturers to find economically feasible substitutes.
42	Ferrous Metal Production
43	Nonferrous Metal Production
44	Pollution Air pollution Global scale air pollution Regional scale air pollution Local scale air pollution Water pollution Water pollution sources Impact on aquatic life Wastewater and disease Land pollution Solid waste disposal Toxic pollutants
45	Air Pollution Air pollution is a concentration of trace substances at a greater level than occurs in average air. The most common air pollutants are carbon monoxide, sulfur dioxide, nitrogen oxides, hydrocarbons, and solid particulates. Three human activities generate most air pollution: motor vehicles, industry, and power plants. In all three cases, pollution results from the burning of fossil fuels. Air pollution concerns geographers at three scales—global, regional, and local. Air pollution may contribute to global warming and damage the atmosphere’s ozone layer. It may also be damaging the atmosphere’s ozone layer.
46	Global Warming Human actions, especially the burning of fossil fuels, are causing Earth’s temperature to rise. Earth is warmed by sunlight that is converted to heat. When the heat tries to pass back through the atmosphere to space, some gets through and some is trapped. A concentration of trace gases in the atmosphere can block or delay the return of some of the heat leaving the surface heading for space. Plants and oceans absorb much of the discharges, but increased fossil-fuel burning during the past 200 years has caused the level of carbon dioxide in the atmosphere to rise by more than one-fourth.
47	Global Temperatures, 1880–2000
48	Global-Scale Ozone Damage The stratosphere contains a concentration of ozone gas. The ozone layer absorbs dangerous ultraviolet (UV) rays from the Sun. Earth’s protective ozone layer is threatened by pollutants called chlorofluorocarbons (CFCs). The 1987 Montreal Protocol called for more developed countries to cease using CFCs by 2000, and for LDCs to cease by 2010.
49	Effects of Acid Rain Industrialized, densely populated regions in Europe and eastern North America are especially affected by acid deposition. Sulfur oxides and nitrogen oxides, emitted by burning fossil fuels, enter the atmosphere, where they combine with oxygen and water. Tiny droplets of sulfuric acid and nitric acid form and return to Earth’s surface as acid deposition. When dissolved in water, the acids may fall as acid precipitation—rain, snow, or fog. These acidic droplets might be carried hundreds of kilometers. Acid precipitation has damaged lakes, killing fish and plants. On land, concentrations of acid in the soil can injure plants by depriving them of nutrients and can harm soil worms and insects. Buildings and monuments made of marble and limestone have suffered corrosion from acid rain.
50	Acid Deposition
51	Air Pollution The worst U.S. city for concentrations of carbon monoxide and second worst for particulates is Denver. The Rocky Mountains help trap the gases and produce a permanent temperature inversion. The problem is not confined to MDCs. Santiago, Chile, nestled between the Pacific Ocean and the Andes Mountains, suffers severe smog problems. Progress in controlling urban air pollution is mixed. Air has improved in developed countries where strict clean-air regulations are enforced. But more people are driving, offsetting gains made by emission controls. Limited emission controls in LDCs are contributing to severe urban air pollution.
52	Local Scale Air Pollution Air pollution is especially severe in local areas where emission sources are concentrated, such as urban areas. Urban areas may be especially polluted because. . polluters emit residuals in a concentrated area. Urban air pollution has three basic components: Carbon monoxide; Hydrocarbons—hydrocarbons and nitrogen oxides in the presence of sunlight form photochemical smog; Particulates—particulates include dust, smoke, (and rubber tire) particles. The severity of air pollution. . . depends on the weather. The worst urban air pollution occurs when winds are slight, skies are clear, and a temperature inversion exists.
53	Water Pollution Water serves many human purposes. These uses depend on fresh, clean, unpolluted water. Clean water is not always available, because people also use water for purposes that pollute it. Pollution is widespread, because it is easy to dump waste into a river and let the water carry it downstream where it becomes someone else’s problem.
54	Water Pollution Sources Three main sources generate most water pollution: Water-Using Industries: Industries . . generate a lot of wastewater. Water can also be polluted by industrial accidents. Municipal Sewage: In more developed countries, sewers carry wastewater to a municipal treatment plant, where most—but not all—of the pollutants are removed. In LDCs, sewer systems are rare, and wastewater usually drains untreated into rivers and lakes. Agriculture: Fertilizers and pesticides spread on fields to increase agricultural productivity are carried into rivers and lakes by the irrigation system or natural runoff. Point-source pollution enters a stream at a specific location, whereas nonpoint-source pollution comes from a large diffuse area. Farmers tend to pollute through nonpoint sources, such as by permitting fertilizer to wash from a field during a storm. Point-source pollutants are usually smaller in quantity and much easier to control.
55	Aral Sea, 1975 and 1996
56	Change in Aral Sea, 1995–96
57	Impact on Aquatic Life If too much waste is discharged into the water, the water becomes oxygen-starved and fish die. The oxygen consumed by the decomposing organic waste constitutes the biochemical oxygen demand (BOD). When runoff carries fertilizer from farm fields into streams or lakes, the fertilizer nourishes excessive aquatic plant production that consumes too much oxygen. Either type of pollution unbalances the normal oxygen level, threatening aquatic plants and animals. Some of the residuals may become concentrated in the fish, making them unsafe for human consumption.
58	Wastewater and Disease Since passage of clean water laws most treatment plants meet high water-quality standards. Improved treatment procedures have resulted in cleaner rivers and lakes in more developed countries. Prior to the Industrial Revolution, the Thames was a major food source for Londoners. During the Industrial Revolution, the Thames became the principal location for dumping waste. The fish died, and the water grew unsafe to drink. The British government began a massive cleanup during the 1960s to restore the Thames to health.
59	Land Pollution When we consume a product, we also consume an unwanted byproduct (the) container in which the product is packaged. About 2 kilograms (4 pounds) of solid waste per person is generated daily in the United States. Even consumers who carefully dispose of solid waste are contributing to a major pollution problem. About one-half of the solid waste generated in the United States is placed in landfills, the other one half recycled in one of two Ways. Most of the recycled solid waste is reused, while the remainder is incinerated for power.
60	Solid Waste Sources, before and after recycling
61	Incineration Burning the trash reduces its bulk by about three-fourths, and the remaining ash demands far less landfill space. Incineration also provides energy to produce steam heat or to operate a turbine that generates electricity. The percentage of solid waste that is burned has increased rapidly during the past quarter century. However, solid waste, a mixture of many materials, may burn inefficiently. Burning releases some toxics into the air, and some remain in the ash
62	Toxic Pollutants Disposing of toxic wastes is especially difficult. Toxic wastes include heavy metals (including mercury, cadmium, and zinc), PCB oils from electrical equipment, cyanides, strong solvents, acids, and caustics. Burial of wastes was once believed to be sufficient to handle the disposal problem, but many of the burial sites have leaked. One of the most notorious is Love Canal, near Niagara Falls, New York. Love Canal is not unique. Toxic wastes have been improperly disposed of at thousands of dumps.
63	Renewing and Recycling Resources Renewing resources Solar energy Other energy sources Uses for renewable energy Recycling resources Recycling collection Other pollution reduction strategies Using all reduction strategies at a coking plant Comparing pollution reduction strategies
64	Renewing Resources Energy poses an especially strong challenge in substituting renewable resources for nonrenewable ones. About 6 percent of energy consumed in the United States is generated by renewable sources.
65	Solar Energy Solar energy is free, doesn't damage the environment or cause pollution, and is quite safe. There are two general approaches to harnessing solar energy: passive and active.
66	Passive solar energy Passive solar energy systems capture energy without special devices. Reliance on passive solar energy increased during the nineteenth century when construction innovations first permitted hanging of massive glass “curtains” on a thin steel frame. With electricity and petroleum cheap and abundant, passive solar energy did not play a major role in construction of homes and commercial buildings through most of the twentieth century. Interest in passive solar energy resumed when petroleum prices rapidly escalated during the l970s. The largest contributor to increased use of passive solar energy has been through advances in glass technology.
67	Active solar energy Active solar energy systems collect solar energy and convert it either to heat energy or to electricity. In direct electric conversion, solar radiation is captured with photovoltaic cells. In indirect electric conversion, solar radiation is first converted to heat, then to electricity. In heat conversion, solar radiation is concentrated with large reflectors and lenses to heat water or rocks.
68	Other Energy Sources Other energy sources include hydroelectric, geothermal, biomass, and fusion. The first three are currently used but offer limited prospects for expansion. Fusion is not a practical source at this time but may be in the future.
69	Hydroelectric Power Water has been a source of mechanical power since before recorded history. It turned water wheels to operate machines. Over the last hundred years the energy of moving water has been used to generate electricity, called hydroelectric power. Hydroelectric power is the world’s second most popular source of electricity, after coal, supplying about a fourth of worldwide demand. Hydroelectric power has drawbacks. Dams may flood formerly usable land, cause erosion, and upset ecosystems. Political problems can result from building dams on rivers that flow through more than one country.
70	Geothermal Energy Earth’s interior is hot from natural nuclear reactions. In volcanic areas hot rocks can encounter groundwater. Energy from this hot water or steam is called geothermal energy. Harnessing geothermal energy is most feasible at the rifts along Earth’s surface where crustal plates meet.
71	Biomass Forms of biomass, such as sugarcane, corn, and soybeans, can be processed into motor vehicle fuels. Burning biomass may be inefficient, because the energy used to produce the crops may be as much as the energy supplied by the crops. The most important limitation on using biomass for energy is that it already serves other essential purposes: providing much of Earth’s food, clothing, and shelter.
72	Nuclear Fusion Some nuclear power problems could be solved with nuclear fusion, which is the fusing of hydrogen atoms to form helium. But fusion can occur only at very high temperatures (which have not been) achieved on a sustained basis in a power-plant reactor. Alternatives such as fusion do not offer immediate solutions to energy shortages in the twenty-first century. The era of dependency on nonrenewable fossil fuels for energy will constitute a remarkably short period of human history.
73	Electricity Efforts to utilize more renewable energy are focused on two sectors: electricity and motor vehicles. In MDCs, solar energy is used primarily as a substitute for electricity in heating water. Solar-generated electricity is used in spacecraft, light-powered calculators, and at remote sites where conventional power is unavailable, such as California’s Mojave Desert. The largest and fastest growing market for photovoltaic cells are the two billion people who lack electricity in LDCs, especially residents of remote villages. The cost of cells must drop and their efficiency must improve for solar power to expand rapidly, with or without government support.
74	Motor Vehicles The most serious obstacle to decreasing reliance on nonrenewable energy is its importance as automotive fuel. The use of electric vehicles is expanding in MDCs, primarily to reduce air pollution rather than to conserve the nonrenewable resource of petroleum. Limitations with electric power have led motor vehicle producers to consider fuel cells instead. As long as petroleum is perceived as cheap and unlimited in supply, alternative fuel vehicles have limited popularity. It will take a major increase in world petroleum prices or disruption in supplies to bring alternative fuel vehicles to the market in large numbers.
75	Recycling Resources Recycling increased in the United States from 7 percent of all solid waste in 1970 to 10 percent in 1980, 17 percent in 1990, and 28 percent in 1999. The amount of solid waste generated by Americans increased by 30 million tons during the 1990s, and all of that additional waste was recycled. The percentage of recovered materials varies widely by product.
76	Recycling Collection Recycling involves two main series of activities. First, materials that would otherwise be “thrown away” are collected and sorted. Then the materials are manufactured into new products for which a market exists.
77	Pickup and Processing Recyclables are collected in four primary methods: curbside, drop-off centers, buyback centers, and deposit programs. Regardless of the collection method, recyclables are sent to a materials recovery facility to be sorted and prepared into marketable commodities for manufacturing.
78	Manufacturing Once cleaned and separated, the recyclables are ready to be manufactured into a marketable product. Four major manufacturing sectors accounted for more than half of the recycling activity: paper mills, steel mills, plastic converters, and iron and steel foundries. The principal obstacle to recycling of plastic is that plastic types must not be mixed, yet it is impossible to tell one type from another by sight or touch. The plastic industry has responded to this problem by developing a series of numbers marked inside triangles on the bottom of containers. Types 1 and 2 are commonly recycled, the others generally are not.
79	Other Pollution by Redaction Strategies Glass is 100 percent recyclable and can be used repeatedly with no loss in quality. Scrap aluminum is readily accepted for recycling, although other metals are rarely accepted. In addition to recycling, two other basic strategies can reduce pollution. The amount of waste discharged into the environment can be reduced, or the capacity of the environment to accept discharges can be expanded.
80	Reducing Discharges Pollution can be prevented if the amount of waste being discharged into the environment is reduced to a level that the environment can assimilate. The mix of various inputs can be adjusted to produce a higher ratio of product to waste. The amount of waste can also be reduced if the production system produces less of the product —or if production ceases altogether—because of lower consumer demand. Emissions-trading systems can reduce discharges, especially into the atmosphere. To reduce sulfur dioxide discharges, the United States introduced a market through an amendment to the 1990 Clean Air Act. Power companies can buy and sell allowances to emit sulfur dioxide. The Chicago Climate Exchange opened in 2003 to promote reduction of greenhouse gases.
81	Increasing Environmental Capacity The second way to handle pollution is to increase environmental capacity to accept waste discharges. The capacity of air, water, and land to accept waste is not fixed, but varies among places and at different times.. A deep, fast-flowing river has a greater capacity to absorb wastewater than a shallow, slow-moving one. Wastewater can be stored when the river level is low and released when the river is high. Similarly, exhaust released into stagnant air irritates, whereas exhaust released in windy conditions is quickly dispersed. Environmental capacity can also be increased by transforming the waste so that it is discharged into a resource that has the capacity to assimilate it.
82	Pollution Reduction at a Coking Plant
83	Comparing Pollution Reduction Strategies Relying on an increase in the capacity of the environment to accept discharges is risky. Recent history is filled with examples of wastes discharged in the environment with the belief that they would be dispersed or isolated safely: CFCs in the stratosphere, garbage offshore, and toxic chemicals beneath Love Canal. Tall smokestacks were successful at dispersing sulfur over a larger area. But the result of the dispersal was that acid precipitation fell hundreds of kilometers away. A pollutant such as sulfur dioxide might exist at tolerable levels in the air, but it damages trees when it accumulates in the soil. Reducing discharges into the environment (by either changing the production process or recycling) is usually the preferred alternative.
84	Resource Conservation Sustainable development Sustainability and economic growth Critics of sustainability Biodiversity Biological and geographic biodiversity Biodiversity in the tropics
85	Conservation “Conservation” is a concept that reflects balance between nature and society. Conservation is the sustainable use and management of natural resources such as wildlife, water, air, and Earth deposits to meet human needs, including food, medicine, and recreation. Conservation differs from preservation, which is maintenance of resources in their present condition, with as little human impact as possible. The concept of preservation does not regard nature as a resource for human use. In contrast, conservation is compatible with development but only if natural resources are utilized in a careful rather than a wasteful manner. An increasingly important approach to careful utilization of resources is sustainable development, based on promotion of biodiversity.
86	Pollution and National Wealth
87	Sustainability and Economic Growth The U.N. ‘s “sustainable development” was defined in the 1987 Brundtland Report. Environmental protection, economic growth, and social equity are linked because economic development aimed at reducing poverty can at the same time threaten the environment. A rising level of economic development generates increased pollution, at least until a country reaches a GDP of about $5,000 per person. Consequently, twentieth-century environmental improvements in the more developed countries of North America and Western Europe are likely to be offset by increased pollution in LDCs during the twenty-first century.
88	Sustainability’s Critics Some environmentally oriented critics have argued that it is too late to discuss sustainability. The World Wildlife Federation (WWF), for example, claims that the world surpassed its sustainable level around 1980. Others criticize sustainability from the opposite perspective: human activities have not exceeded Earth’s capacity, because resource availability has no maximum. Earth’s resources have no absolute limit, because the definition of resources changes drastically and unpredictably over time. Environmental improvements can be achieved through careful assessment of the outer limits of Earth’s capacity. Critics and defenders of sustainable development agree that one important recommendation of the UN report has not been implemented: increased international cooperation to reduce the gap between more developed and less developed countries.
89	Biodiversity Biological diversity, or biodiversity for short, refers to the variety of species across Earth as a whole or in a specific place. Sustainable development is promoted when biodiversity of a particular place or Earth as a whole is protected.
90	Biological and Geographic Biodiversity Species variety can be understood from several perspectives. Geographers are especially concerned with biogeographic diversity, whereas biologists are especially concerned with genetic diversity. Estimates of Earth’s total number of species range from 3 to 100 million, with 10 million as a median “guess,” meaning that humans have not yet “discovered,” classified, and named most of Earth’s species. For geographers, biodiversity is measurement of the number of species within a specific region or habitat.
91	Biodiversity in the Tropics Reduction of biodiversity through species extinction is especially important in tropical forests. Three species per hour are extinguished in the tropics, and more than 5,000 species are considered in danger of extinction. Tropical forests occupy only 7 percent of Earth’s land area but contain more than one-half of the world’s species, including two-thirds of vascular plant species and one-third of avian species. The principal cause of the high rate of extinction is cutting down forests. Rapid deforestation results from changing economic activities in the tropics, especially a decline in shifting cultivation (see Chapter 10).
92	Financing Development in the Tropics Governments in developing countries support the destruction of rain forests, because they view activities such as selling timber to builders or raising cattle for fast-food restaurants as more effective strategies for promoting economic development than shifting cultivation. Until recently, the World Bank has provided loans to finance development proposals that require clearing forests. The problem with shifting cultivation compared to other forms of agriculture is that it can support only a low level of population in an area without causing environmental damage. Tropical rain forests are disappearing at the rate of 10 to 20 million hectares (25 to 50 million acres) per year. The amount of Earth’s surface allocated to tropical rain forests has been reduced to less than one-half of its original area during the past quarter century. And unless drastic measures are taken, the area will be reduced by another one-fifth within a decade.
93	Resource Issues Chapter 14