CH-13-14 Water Resources – Living in the Environment: Principles, Connections, and Solutions : Book Guide

This Document Contains Chapters 13 to 14 Chapter 13 Water Resources Summary 1. Approximately 0.024% of the earth’s water supply is available as liquid freshwater. Management of the world’s water supply is a huge 21st century challenge. 2. Freshwater shortages are caused by dry climate, droughts, desiccation, and water stress. Solutions for this problem include building dams and reservoirs, transporting freshwater between locations, withdrawing groundwater, and desalination. 3. Advantages of dams and reservoirs include cheap electricity, reduction of downstream flooding, and year-round water for irrigation. Disadvantages include displacement of people and disruption of aquatic systems, and the hydrological cycle. 4. Transferring large amounts of water from one area to another can give stream runoff from water-rich areas to water-poor areas and aid in irrigation of farmland. It can also cause ecological, economical, and health disasters. 5. The advantages of withdrawing groundwater include water for drinking and irrigation; availability and locality; low cost, no evaporation losses; and it is renewable. Disadvantages include aquifer depletion from over pumping, subsidence, pollution, saltwater intrusion, and reduced water flow. Desalination increases the supply of fresh water but is expensive and produces large quantities of wastewater. 6. We can waste less water by lining canals, leveling fields, irrigating at night or using new irrigation techniques, polyculture or organic farming, seasonal farming, irrigating with treated waste water, and importing water-intensive crops and meat. 7. Flooding is caused by heavy rain or melting of snow within a short time. To reduce flood damage or the risk of flooding we can avoid building on floodplains, removing water-absorbing vegetation, or draining wetlands. 8. Methods for achieving more sustainable use of the earth’s water include not depleting aquifers, preserving aquatic systems and water quality, integrated watershed management, agreements among regions and countries sharing surface water resources, outside party mediation of water dispute nations, marketing of water rights, raising water prices, wasting less water, decreasing government subsidies for reducing water waste, and slowing population growth. Key Questions and Concepts 13-1 Will we have enough usable water? CORE CASE STUDY: The Colorado River is 1,400 miles long and has been altered by 14 major dams and reservoirs. This river provides water and electricity for 30 million people and irrigation to grow 15% of the nation’s crops and livestock. A. Water keeps us alive, moderates climate, sculpts the land, removes and dilutes wastes and pollutants, and moves continually through the hydrologic cycle. B. Only about 0.024% of the earth’s water supply is available to us as liquid freshwater in accessible groundwater deposits and in lakes, rivers, and streams. The hydrologic cycle collects, purifies, recycles, and distributes the world’s freshwater supply. Some countries have more water than they need; some countries have far less. C. Some precipitation infiltrates the ground and percolates downward through spaces in the soil, gravel, and rock. This water is known as groundwater, an important fresh water source. D. Water that does not sink into the ground or evaporate into the air runs off into bodies of water. This is known as surface water. E. We currently withdraw 34% of the world’s reliable runoff of surface water and could be using 90% by 2025. F. Irrigation is the biggest user of water (70%), followed by industries (20%) and cities and residences (10%). CASE STUDY: The United States has plenty of freshwater, but supplies vary in different areas depending on climate. This unequal distribution of water can be seen in Figure 14-4. There are water hot spots in 17 western states (Figure 14-5), that could trigger intense conflict in the next 20 years. SCIENCE FOCUS: Water footprint refers to the rough measure of volume of water used by each of us directly and indirectly. Direct use in the United States amounts to about 69 gallons per person. In addition, virtual water accounts for water that is not directly consumed, but is used to produce food and other products. G. More than 30 countries now face water scarcity. By 2050, 60 countries, mostly in Asia, with ¾ of the world population will suffer from water stress. H. Conflicts between nations over water resources are likely to grow, as many nations that share water supplies to not have water sharing agreements. 13-2 Is extracting groundwater the answer? A. Most aquifers are renewable resources unless water is removed faster than it is replenished or the aquifers are contaminated. Aquifers provide almost one-fourth of the world’s water. B. In many parts of the world, aquifers are being depleted faster than they are renewed. 1. Water tables are falling in many areas of the world because the rate of pumping out water (mostly to irrigate crops) exceeds the rate of natural recharge from precipitation. 2. The widespread drilling of inexpensive tube wells by small farmers, especially in Asia, has accelerated aquifer over pumping. 3. Saudi Arabia gets 70% of its water from the world’s largest desalination complex. CASE STUDY: In the United States, groundwater is being withdrawn four times faster than it is being replenished. In the Central U.S., government subsidies to farmers have increased depletion of the Ogallala aquifer. C. Groundwater over pumping can increase the gap between the rich and the poor, cause land to sink, and contaminate freshwater aquifers near coastal areas with saltwater. D. Deep aquifers may be a future water source. There are major concerns with their use. 1. They are nonrenewable. 2. Little is known of the geological or ecological impacts of their use. 3. Some flow under more than one nation. 4. The costs are unknown and could be high. 13-3 Is building more dams the answer? A. Large dams and reservoirs can produce cheap electricity, reduce downstream flooding, and provide year-round water for irrigating cropland, but they also displace people and disrupt aquatic systems. 1. There are more than 45,000 large dams in the world. B. The Colorado River is an example of unsustainable water use. 1. 80% of this water is used for agriculture, and much is lost to seepage and evaporation. 13-4 Is transferring water from one place to another the Answer? A. Transferring water can make unproductive areas more productive but can cause environmental harm. CASE STUDY: The California Water Project provides for a massive transfer of water from water-rich northern California to water-poor southern California. This has allowed for the development of agriculture and urban areas in desert-like conditions. However, this has degraded river ecosystems and fisheries. CASE STUDY: Diverting water from the Aral Sea and its two feeder rivers mostly for irrigation has created a major ecological, economic, and health disaster. This activity has increased the salinity of the sea sevenfold since 1961, the surface area has decreased, and 90% of its water volume has been lost. About 85% of the area’s wetlands have been eliminated; roughly half the birds and mammal species have disappeared. The fishing industry has disappeared, and salt and contaminant-rich dust from exposed lake sediments are creating a major dust pollution source for the region. Some artificial wetlands and lakes have been constructed to help restore aquatic vegetation, wildlife, and fisheries. With the various improvements, the water volume in the Aral Sea has stabilized though at a much lower level than prior to water diversions. 13-5 Is converting salty seawater to freshwater the answer? A. Removing salt from seawater by current methods is expensive, produces large amounts of salty wastewater that must be disposed of properly, and can be detrimental to many marine organisms. The process is known as desalination. Methods include distillation and reverse osmosis. SCIENCE FOCUS: The search for improved desalination technology has led to dramatic reductions in cost, and many ideas and methods that would reduce the environmental impact. 13-6 How can we use water more sustainably? A. We waste about two-thirds of the water we use, but this waste could be cut to 15% through reduced evaporation and leakage and improved efficiency of use. B. Higher water costs would reduce waste. C. Sixty percent of the world’s irrigation water is currently wasted, but with improved irrigation techniques such as center-pivot, low-pressure sprinkler irrigation, Low-Energy Precision Application (LEPA), and drip irrigation systems could cut this waste to 5–20%. D. Many poor farmers in developing countries use low-tech methods to pump groundwater and make more efficient use of rainfall. E. Industries can recycle much of the water they use; and homeowners can use water-saving toilets, appliances, and showerheads, fix leaks, use drip irrigation and yard plants that need little water (xeriscaping), save and reuse rainwater, and reuse wastewater for some purposes. 13-7 How can we reduce the threat of flooding? A. Heavy rainfall, rapid snowmelt, removal of vegetation, and destruction of wetlands cause flooding. Floods occur when a stream overflows its normal channel and spills into a floodplain. 1. Flood can be beneficial in recharging groundwater and depositing nutrients. 2. Floods can also be detrimental to communities and property. 3. Several factors increase flooding a. The removal of water absorbing vegetation b. Draining and building on wetlands c. Climate change CASE STUDY: Bangladesh has experienced increased flooding because of upstream deforestation of Himalayan mountain slopes and the clearing of mangrove forests on its coastal floodplains. Bangladesh is one of the world’s most densely populated countries, and is very flat. The people of Bangladesh depend on the moderate annual flooding to maintain soil fertility. Great floods used to occur about every 50 years or so, but since the 1970s they now occur about every 4 years. B. We can reduce flooding risks by controlling river water flows, protecting mountainside forests, preserving and restoring wetlands, identifying and managing flood-prone areas, and, if possible, choosing not to live in such areas. Teaching Tips Larger Lecture Courses: Begin lecture with an evaluation of local water supply. Ask students (using a clicker response poll or ask for individual responses) where local water comes from. Discuss problems with local water supply. Review water billing approaches in your city—do you pay for water on a tiered system or with a flat rate independent of how much is used? (Link back to discussions of environmental economics.) If you are using clickers, start a poll of the class after reviewing the state of the global water supply. Ask students if they feel the solution to this problem lies in groundwater extraction, dams, water transfers, desalinization, or conservation (e.g., the key chapter questions and concepts). Challenge the rationale behind the most popular answer and use this to begin the discussion of potential approaches to sustainable water use. Smaller Lecture Courses: Assign a pre-class assignment of reading the city or county water treatment and supply web pages. Ask students to report back on local water use rules, rates, and supply issues. As an in-class exercise, ask students to evaluate and revise water pricing structures for the city—raise the question of how economics and regulation interact in the water market. Ask about how to price for non-market values of water. For classes in areas with ample water supplies, highlight Africa’s water use for the course. Discuss the links between drought, famine, and conflict in Africa. For classes in the Western U.S., talk about allocation of Colorado River Water in the past and the future. Key Terms aquifers dam desalination drainage basin drought floodplain groundwater reliable surface runoff reservoir surface runoff surface water water table watershed zone of saturation Term Paper Research Topics 1. Flooding: history of flooding in the United States or Asia: change in rates and possible causes. 2. Droughts: drought history of the African Sahel. 3. Water supply through dams and water transfer projects: trickle irrigation; water diversion projects in China and India; new dams in South America and their effects on indigenous people; the James Bay project; the California Water Project; the Columbia River. 4. Water supply through groundwater: urban construction and aquifer recharge problems; the Ogallala Aquifer. 5. History of the Colorado River Compact: past and current problems. 6. Drought and climate change: review evidence for links between climate change and increased frequency and severity of drought. 7. Cloud seeding and climate modification: Who owns the water in the clouds? 8. What role has water supply played in wars between countries in the last decade? 9. Who has the strongest claim on California's water supply: the farmers or the cities? 10. Is the public ready for water recycling? Discussion Topics 1. Do we have enough water to support continued population growth? How many more people can be supported? Answer: Global water resources are finite and unevenly distributed, making it challenging to support indefinite population growth. While some regions have ample water, others face severe shortages. The number of additional people that can be supported depends on sustainable water management practices, technological advancements in water conservation, and efficient allocation among competing uses. 2. Who should be responsible for water management? Who should make and enforce decisions when water crosses state lines or international boundaries? Answer: Water management responsibilities should be shared among local, state, and federal governments, with cooperation from international bodies where necessary. For water that crosses state or international boundaries, decisions should be made collaboratively through treaties, agreements, and oversight by entities like the United Nations or regional water commissions to ensure equitable distribution and conflict resolution. 3. Ask students to rank the priorities for water use (e.g., industry, agricultural, municipal). Compare this list against water rights in your state. Are they similar or different? Answer: Students may prioritize municipal use, agriculture, and industry differently based on perceived needs and values. Comparing this list with state water rights, which often prioritize agricultural and industrial uses due to economic considerations, may reveal differences. For example, in many states, water rights historically favor agricultural uses, potentially diverging from public opinion on prioritizing municipal and drinking water needs. 4. Bring in a bottle of water imported from someplace very far away. Compare the cost of that water to tap water and other goods (e.g., gasoline). Examine water quality reports from tap and bottled water to compare claims of better quality in bottled water. Answer: Imported bottled water can be significantly more expensive than tap water, with costs often exceeding those of gasoline on a per-liter basis. While bottled water is marketed as being of superior quality, water quality reports often show that tap water meets or exceeds safety standards, debunking claims of bottled water's superiority. Factors such as convenience, taste, and brand perception drive consumer preferences for bottled water. 5. Read from John Wesley Powell journals or congressional testimony in the mid-1800s. Did we make the right decisions about the development of the western U.S.? Answer: John Wesley Powell advocated for development plans in the western U.S. based on the region's arid conditions, emphasizing water management and sustainable use. Historical decisions often prioritized rapid development and agricultural expansion, sometimes disregarding water scarcity issues. In hindsight, more conservative and environmentally conscious development might have better preserved water resources and reduced long-term water scarcity challenges. 6. Discuss the 2007/2008 SE U.S. drought. Review newspaper accounts and ask what should have been done to address this problem. Answer: The 2007/2008 SE U.S. drought highlighted the need for improved water management, conservation, and infrastructure. Newspaper accounts from the time often emphasized the lack of preparedness and the need for better water-use regulations and drought planning. Addressing the problem required coordinated efforts to reduce consumption, enhance water storage, and promote sustainable practices. Future preparedness plans should include these measures to mitigate the impact of similar droughts. Activities and Projects 1. Ask your class to determine the local agricultural and industrial uses of water. Is irrigation used widely? What is the source of irrigation water? What water conservation practices are used by local government, industry, and agriculture? 2. Ask your students to bring to class and share paintings, photographs, poems, songs, or other expressions of intense human feelings about water as a life-sustaining and precious substance. 3. Invite a local, state, or federal water-supply official to discuss water-supply problems of your area with your class. Investigate the water-supply needs of your area and the strategies that are being used to meet those needs. 4. IN CLASS. Investigate environmental impacts of the dam. Draw a model of all of the factors that create positive and negative loops as a result of the dam. 5. Have your students explore community water resources. Where does your town get its water? What is the average daily use in summer? In winter? What are the major uses in your area? (List the ten biggest users.) How much does your class use? 6. FIELD TRIP. If a dam has been constructed or is being built in your area, visit the site with your class. Ask students to find pictures of the area and its water control problems before the dam was built, evaluate whether the dam should have been built, and substantiate their claims. Were there alternatives to dam construction? What is the expected lifetime of the dam? 7. Have student do a daily water use audit. Estimate their water use for a day of normal use and evaluate how much could be saved through conservation. Bring these estimates to class and extrapolate the estimates to the city, state, and national level. Attitudes and Values 1. Do you consume too much water? Does your community consume too much water? Answer: Personal and community water consumption varies widely. While some individuals and communities practice conservation, others may consume water excessively, especially in regions with ample supply. Assessing consumption requires considering usage habits, local water availability, and conservation efforts, with excessive use often linked to wasteful practices or inefficient infrastructure. 2. Is access to water a basic human right? If so, how should we respond to droughts around the world? Answer: Access to clean water is widely considered a basic human right. In response to global droughts, efforts should focus on ensuring equitable distribution, investing in sustainable water infrastructure, and providing aid to affected regions. International cooperation and support for water conservation technologies are crucial in addressing water scarcity and securing this fundamental right. 3. How would you assess the pros and cons of dam construction? Why do you rank some issues (e.g., watershed protection, fisheries) over others (e.g., electricity generation or flood control)? Answer: The pros of dam construction include electricity generation, flood control, and water storage, while cons involve environmental disruption, displacement of communities, and impacts on ecosystems. Prioritizing issues like watershed protection and fisheries over others may stem from valuing long-term environmental health and biodiversity, essential for sustainable ecosystems, over short-term economic gains. 4. What obligation do we have, if any, to protect groundwater supplies for the future? Answer: We have a significant obligation to protect groundwater supplies to ensure sustainable access for future generations. Over-extraction and contamination can deplete and degrade these resources, necessitating careful management and conservation measures. Protecting groundwater involves regulating usage, preventing pollution, and promoting recharge through sustainable practices. 5. How does our pricing of water reflect our value systems? Is the pricing of water changing in the U.S.? How and why? Answer: Water pricing reflects societal values, balancing affordability with the need to fund infrastructure and conservation efforts. In the U.S., water pricing is increasingly shifting towards reflecting the true cost of supply and scarcity, driven by concerns over sustainability and the need to manage demand. This change encourages conservation and ensures fair allocation of resources. 6. Do you favor increasing the price of irrigation water to reflect its true cost and encourage conservation among farmers? How do you balance conservation goals against local impacts? Answer: Increasing the price of irrigation water can incentivize conservation among farmers by reflecting its true cost. However, this must be balanced against the potential economic impact on local agriculture and food production. Policies could include subsidies for water-efficient technologies or tiered pricing structures to support smaller farmers while promoting sustainable practices. News Videos Half the World Denied Basic Sanitation; The Brooks/Cole Environmental Science Video Library, 2009; DVD 0538733551 Tapped Out Atlanta Resident Uses 400,000 Gallons of Water a Month; Environmental Science in the Headlines, 2008; DVD; ISBN 0495561908 Water Wars: States Battle Through Drought; Environmental Science in the Headlines, 2008; DVD; ISBN 0495561908 Additional Video Resources After the Storm (Documentary, free DVD or VHS) Looks at watersheds and their importance in various parts of the U.S. http://www.epa.gov/weatherchannel/video.html Conserving America (PBS, 1994) A four-part series on American conservation of wetlands. The Habitable Planet: A Systems Approach to Environmental Science, Water Resources ( (Documentary series, 2007). This video explores optimum water use for humans and ecosystems. http://www.learner.org/resources/series209.html Planet Earth Series (Discovery Channel, TV Series) http://dsc.discovery.com/convergence/planet-earth/planet-earth.html We all Live Downstream (Documentary, 1991) A look at pollution in the Mississippi River and the effects on human health. http://www.videoproject.com/wea-281-v.html Web Resources United Nations Environment Program Global freshwater supplies and trends. http://www.unep.org/themes/Freshwater/ NASA Earth Observatory Science of the water cycle. http://earthobservatory.nasa.gov/Library/Water/water_2.html The Nature Conservancy Sustainable waters initiative of the Nature conservancy. http://www.nature.org/initiatives/freshwater/ The U.S. Environmental Protection Agency Freshwater ecosystems. http://www.epa.gov/bioindicators/aquatic/freshwater.html Suggested Responses to End of Chapter Questions Review Questions 1. Review the Key Questions and Concepts for this Chapter on p. 318. Discuss the importance of the Colorado River basin in the United States and how human activities are stressing this system. Answer: • The Colorado River basin includes some of the driest lands in the United States and Mexico. For its size, the river has only a modest flow of water. Legal pacts signed in 1922 and 1944 allocated more water for human use in the United States and Mexico than the river can supply— even in rare years without a drought. Since 1905, the amount of water flowing to the mouth of the Colorado River has dropped dramatically. Since 1960, the river has rarely made it to the Gulf of California because of the many dams, the increased water withdrawals, and a prolonged drought in the American Southwest, which is projected to last throughout this century. This threatens the survival of species that spawn in the river and species that live in its estuary near the coast. 2. Explain why access to water is a health issue, an economic issue, a women’s and children’s issue, a national and global security issue, and an environmental issue. Describe how water is recycled by the hydrologic cycle and how human activities can overload and altered this cycle. What percentage of the earth’s freshwater is available to us? Answer: • Access to water is a global health issue because an average of 3,900 children younger than age 5 die from waterborne infectious diseases because they do not have access to safe drinking water. It is an economic issue because it is vital for reducing poverty and producing food and energy. It is an issue for women and children in less-developed countries because almost half of the world’s people do not have water piped to their homes and women generally bear the burden of accessing water. It is also a national and global security issue because of increasing tensions both within and between nations over access to limited water resources. It is also an environmental issue because excessive withdrawal of water from rivers and aquifers results in falling water tables, decreasing river flows, shrinking lakes, and disappearing wetlands. • The hydrologic cycle collects, purifies, recycles, and distributes the earth’s water supply. Human activities can overload it with pollutants or result in the withdrawal of water from underground and surface water supplies faster than it can be replenished. We can also alter precipitation rates and distribution patterns of water through our influence on climate change. • Only about 0.024% of the world’s freshwater is available to us. 3. Define groundwater, zone of saturation, water table, and aquifer. Distinguish among surface water, surface runoff, and reliable surface runoff. What percentage of the world’s reliable runoff are we using and what percentage are we likely to be using by 2025? Describe the availability and use of freshwater resources in the United States. Explain why much of the area in 36 states is likely to suffer from water shortages throughout most of this century. What are five major problems resulting from the way people are using water from the Colorado River basin? Answer: • Some precipitation infiltrates the ground and percolates downward through spaces in soil, gravel, and rock until an impenetrable layer of rock stops it. The water in these spaces is called groundwater. • The spaces in soil and rock close to the earth’s surface hold little moisture. Below a certain depth, in the zone of saturation, these spaces are completely filled with water. • The top of this groundwater zone is the water table. It falls in dry weather, or when we remove groundwater faster than nature can replenish it, and it rises in wet weather. • Deeper down are geological layers called aquifers: underground caverns and porous layers of sand, gravel, or bedrock through which groundwater flows. • Surface water is the freshwater from precipitation and snowmelt that flows across the earth’s land surface and into lakes, wetlands, streams, rivers, estuaries, and ultimately to the oceans. • Precipitation that does not infiltrate the ground or return to the atmosphere by evaporation is called surface runoff. • Two-thirds of the annual surface runoff in rivers and streams is lost by seasonal floods and is not available for human use. The remaining one-third is reliable surface runoff, which we can generally count on as a source of freshwater from year to year. • A drought is a prolonged period in which precipitation is at least 70% lower than average and evaporation is higher than normal in a particular area. • We now withdraw about 34% of the world’s reliable runoff. Because of increased population growth alone, global withdrawal rates of surface water could reach more than 70% of the reliable runoff by 2025, and 90% if per capita withdrawal of water continues increasing at the current rate. • The United States has more than enough renewable freshwater; but it is unevenly distributed, and much of it is contaminated by agricultural and industrial practices. The eastern states usually have ample precipitation, whereas many western and southwestern states have little rain. Water tables in many water-short areas, especially in the arid and semiarid western half of the lower 48 states, are dropping quickly as farmers and rapidly growing urban areas deplete many aquifers faster than they can be recharged. About 79% of the water used in the United States is used for irrigating crops and removing heat from electric power plants. In the western half of the United States, irrigation accounts for 85% of water use. In the East, most water is used for power plant cooling and manufacturing. • As many as 36 states are likely to face water shortages because of a combination of drought, rising temperatures, population growth, urban sprawl, and increased use and waste of water. • The Colorado River basin includes some of the driest lands in the United States and Mexico. For its size, the river has only a modest flow of water. Legal pacts signed in 1922 and 1944 between the United States and Mexico allocated more water for human use than the river can supply. Since 1960, the river has rarely flowed all the way to the Gulf of California because of reduced water flow, increased water withdrawals, and prolonged drought. And finally, the river receives enormous amounts of pollutants. 4. How many countries face water scarcity today and how many may face water scarcity by 2050? What percentage of the earth’s land suffers from severe drought today and how might this change by 2059? How many people in the world lack regular access to clean water today and how high might this number grow by 2025? Define and give an example of a water footprint. What is virtual water? Why do many analysts view the likelihood of greatly increasing water shortages as one of the world’s most serious environmental problems? Describe the connection between water shortages, grain imports, food prices, and malnutrition. Answer: • Today 30 countries face water scarcity, and that number may rise to 60 by 2050. • About 30% of the earth’s land suffers from draught and that number could rise to 45% by 2059. • 1.2 billion people lack access to clean water, and that number could rise to 3 billion by 2025. • A water footprint is a rough measure of the volume of water that we use directly and indirectly to keep ourselves alive and to support our lifestyles. An example would all of the water each of us use directly and indirectly. • Virtual water is Water that is not directly consumed but is used to produce food and other products. • Water shortages are seen as the most serious environmental problems because they can lead to greatly increased incidences of sickness and death from drinking contaminated water, millions of environmental refugees in search of water, land, and food; and intense conflicts within and between countries. • Some countries that lack water reduce their irrigation demand by importing grain. This allows for more development. As grain prices rise, financially strong nations will have a clear advantage. 5. What are the advantages and disadvantages of withdrawing groundwater? Describe the problem of groundwater depletion in the world and in the United States, especially over the Ogallala aquifer. Describe the problems of land subsidence and contamination of freshwater aquifers near coastal areas resulting from the overdrawing of water from aquifers. Describe ways to prevent or slow groundwater depletion, including the possible use of deep aquifers. Answer: • Advantages of withdrawing groundwater include: ○ Useful for drinking and irrigation. ○ Available year-round. ○ Exists almost everywhere. ○ Renewable if not over pumped or contaminated. ○ No evaporation losses. ○ Cheaper to extract than most surface waters. • Disadvantages of withdrawing groundwater include: ○ Aquifer depletion from over pumping. ○ Sinking of land (subsidence) from over pumping. ○ Aquifers polluted for decades or centuries. ○ Saltwater intrusion into drinking water supplies near coastal areas. ○ Reduced water flows into surface waters. ○ Increased cost and contamination from deeper wells. • In the United States, groundwater is being withdrawn, on average, four times faster than it is replenished. One of the most serious overdrafts is in the lower half of the Ogallala aquifer, which supplies about one third of all the groundwater used in the United States and has helped turn the Great Plains into a productive agricultural region. The Ogallala has a very slow rate of recharge. In some areas, water is being pumped out at a rate that is 10–40 times higher than the natural recharge rate, which has lowered water tables and increased pumping costs. Government subsidies designed to increase crop production and encourage farmers to grow water-thirsty crops in dry areas have encouraged depletion of the Ogallala. • Overdrawing water near coastal areas can pull saltwater into freshwater aquifers. The resulting contaminated groundwater is undrinkable and unusable for irrigation. • Ways to prevent groundwater depletion include waste less water, subsidize water conservation, limit number of wells, and do not grow water-intensive crops in dry areas. Control includes: raise price of water to discourage waste, tax water pumped from wells near surface waters, set and enforce minimum stream flow levels, and divert surface water in wet years to recharge aquifers. In the future, people may be able to access large reserves of water in deep aquifers, although there are several concern and drawbacks to this solution. 6. What is a dam? What is a reservoir? What are the advantages and disadvantages of using large dams and reservoirs? Describe what has happened to water flows in the Colorado River since 1960, other problems that are likely to further decrease its supply of water, and the likely consequences of such changes (Core Case Study). What ecological services do rivers provide? Describe some problems associated with the use of the Colorado River basin. What are the advantages and disadvantages of China’s Three Gorges Dam? Answer: • Large dams are structures built across rivers to block some of the flow of water. • Reservoirs store water collected behind the dams. • Trade-offs: advantages and disadvantages of large dams and reservoirs. Dams and reservoirs capture and store runoff and release it as needed to control floods, generate electricity, and supply water for irrigation and for towns and cities. Reservoirs also provide recreational activities such as swimming, fishing, and boating. Worldwide, dams have displaced 40– 80 million people from their homes. Dams have flooded an area of mostly productive land roughly equal to the area of the U. S. state of California, and it has impaired some of the important ecological services rivers provide. And according to the 2007 WWF study, about one- fifth of the world’s freshwater fish and plant species are either extinct or endangered primarily because dams and water withdrawals have destroyed many free- flowing rivers. • Rivers deliver nutrients to sea to help sustain coastal fisheries, deposit silt that maintains deltas, purify water, renew and renourish wetlands and provide habitats for wildlife. • Since 1960, the Colorado has rarely flowed all the way to the Gulf of California because of its reduced water flow, increased water withdrawals, and prolonged drought. If the climate continues to warm, mountain snows that feed the river will melt faster and earlier, and the melt water will evaporate in greater amounts, making less water available to the river system. If there was a 20% drop in the river’s flow, there is about a 50% chance that its reservoirs will be depleted by 2057. Additionally, evaporation, reservoir leakage, and siltation threatened to further reduce water availability. • Possible solutions include enacting and enforcing strict water conservation measures to slow urban population growth and urban development, eliminating subsidies for agriculture in this region, and prohibiting the use of water to keep golf courses and lawns green. 7. Describe the California Water Project and the controversy over this water transfer project. Describe the environmental disaster caused by the Aral Sea water transfer project. Define desalination and distinguish between distillation and reverse osmosis as methods for desalinating water. What are three major limitations on the widespread use of desalination? What are scientists doing to try to deal with these problems? Answer: • One of the world’s largest water transfer projects is the California Water Project.. It uses giant dams, pumps, and aqueducts to transport water from water rich northern California to water-poor southern California’s heavily populated agricultural regions and cities. This project supplies massive amounts of water to areas that, without such water transfers, would be mostly desert. For decades, northern and southern Californians have feuded over how the state’s water should be allocated under this project. Southern Californians want more water to grow more crops and to support growing urban areas. Northern Californians counter that sending more water south degrades the Sacramento River, threatens fisheries, and reduces the river’s power to flush pollutants out of San Francisco Bay. They point to studies showing that making irrigation just 10% more efficient would provide enough water for domestic and industrial uses in southern California. But low water prices, mostly because government subsidies make it uneconomical for farmers to invest in improving irrigation efficiency. • The shrinking of the Aral Sea is the result of a large-scale water transfer project in an area of the former Soviet Union with the driest climate in central Asia. Since 1960, enormous amounts of irrigation water have been diverted to create one of the world’s largest irrigated areas. This large- scale water diversion project, coupled with droughts and high evaporation rates, has caused a regional ecological and economic disaster. • Desalination involves removing dissolved salts from ocean water or from brackish water for domestic use. The two most widely used methods are distillation and reverse osmosis. Distillation involves heating saltwater until it evaporates (leaving behind salts in solid form) and condenses as freshwater. Reverse osmosis (or microfiltration) uses high pressure to force saltwater through a membrane filter with pores small enough to remove the salt. • There are three major problems with the widespread use of desalination. ○ Desalination is expensive, because it takes a lot of energy to desalinate water. Pumping desalinated water inland also takes a lot of energy and is costly. ○ Pumping large volumes of seawater through pipes and using chemicals to sterilize the water and keep down algae growth kills many marine organisms and also requires large inputs of energy to run the pumps. ○ Desalination produces huge quantities of salty wastewater that must go somewhere. • Scientists are attempting to develop membranes for reverse osmosis that can separate water from salt more efficiently and with less pressure. With less energy required for the process, it may be possible to rely on solar energy. 8. What percentage of available freshwater is unnecessarily wasted in the world and in the United States? What are two major causes of water waste? Describe four irrigation methods and list ways to reduce water waste in irrigation in more- and less-developed countries. List four ways to reduce water waste in industry and homes, and three ways to use less water to remove wastes. List four ways to use water more sustainably and four ways in which you can reduce your use and waste of water. Answer: • About two-thirds of the water used throughout the world is unnecessarily wasted. In the United States, about half is wasted. • Two major causes of water waste are the low cost to consumers and the lack of government subsidies to encourage efficient water use. • Four irrigation methods include: 1 ○ Flood irrigation method delivers far more water than is needed for crop growth and typically loses 40% of the water through evaporation, seepage, and runoff. This system obtains water from a groundwater well or a surface water source. The water then flows by gravity through unlined ditches in crop fields so the crops can absorb it. ○ The center-pivot, low-pressure sprinkler, which uses pumps to spray water on a crop, allows about 80% of the water to reach crops. ○ Low energy, precision application sprinklers, another form of center-pivot irrigation, put 90–95% of the water where crops need it. ○ Drip, or trickle irrigation, also called micro-irrigation, is the most efficient way to deliver small amounts of water precisely to crops. It consists of a network of perforated plastic tubing installed at or below the ground level. Small pinholes in the tubing deliver drops of water at a slow and steady rate, close to the roots of individual plants. • Methods for reducing water waste in irrigation include: ○ Line canals bringing water to irrigation ditches. ○ Irrigate at night to reduce evaporation. ○ Monitor soil moisture to add water only when necessary. ○ Grow several crops on each plot of land (polyculture). ○ Encourage organic farming. ○ Avoid growing water-thirsty crops in dry areas. ○ Irrigate with treated urban wastewater. ○ Import water-intensive crops and meat. • Methods of reducing water waste in industries and homes include: ○ Redesign manufacturing processes to use less water. ○ Recycle water in industry. ○ Landscape yards with plants that require little water. ○ Use drip irrigation. ○ Fix water leaks. ○ Use water meters. ○ Raise water prices. ○ Use waterless composting toilets. ○ Require water conservation in water-short cities. ○ Use water-saving toilets, showerheads, and front-loading clothes washers. ○ Collect and reuse household water to irrigate lawns and inedible plants. ○ Purify and reuse water for houses and apartments. • Ways we can use water more sustainably include: ○ Waste less water and subsidize water conservation ○ Do not deplete aquifers ○ Preserve water quality ○ Protect forests, wetlands, mountain glaciers, watersheds, and other natural systems that store and release water ○ Get agreements among regions and countries sharing surface water resources ○ Raise water prices ○ Slow population growth • See Table 13-24 for more on what individuals can do. 9. What is a floodplain and why do people like to live on floodplains? What are the benefits and drawbacks of floods? List three human activities that increase the risk of flooding. Describe the increased flooding risks that many people in Bangladesh face and what they are doing about it. List three ways to reduce the risks of flooding. Answer: • A flood happens when water in a stream overflows its normal channel and spills into the adjacent area, called a floodplain. People settle on floodplains to take advantage of their many assets, including fertile soil, ample water for irrigation, availability of nearby rivers for transportation and recreation, and flat land suitable for crops, buildings, highways, and railroads. • Floods have created the world’s most productive farmland by depositing nutrient-rich silt on floodplains. They also recharge groundwater and help to refill wetlands, thereby supporting biodiversity and aquatic ecological services. But floods also kill thousands of people each year and cause tens of billions of dollars in property damage. • Human activities that contributed to floods include removal of water-absorbing vegetation and draining and building on wetlands. Another human-related factor that will increase flooding is a rise in sea level from projected climate change. • Those living in many of the world’s largest coastal cities are likely to be at risk from such coastal flooding. Bangladesh’s flooding problems begin in the Himalayan watershed, where rapid population growth, deforestation, overgrazing, and unsustainable farming on steep and easily erodible slopes have increased flow of water during monsoon season. The approaches to dealing with this include using crop varieties that can better tolerate flooding, saltwater, and drought; shifting to new crops such as corn; developing small vegetable gardens in bare patches between houses that can help reduce dependence on rice; building small ponds that can collect monsoon rainwater to use for irrigation; and creating a network of earthen embankments that can help protect against high tides and storm surges. • The risk of flooding can be reduced through channelization, building dams and levees, and preserving/restoring wetland habitat. 10. What are this chapter’s three big ideas? Describe the relationships between water resource problems in the Colorado River basin (Core Case Study) and the three principles of sustainability. Answer: • The three big ideas are: ○ One of the world’s major environmental problems is the growing shortage of freshwater in many parts of the world. ○ We can increase water supplies in water-short areas in a number of ways, but the most important way is to reduce overall water use and waste by using water more sustainably. ○ We can use water more sustainably by cutting water waste, raising water prices, slowing population growth, and protecting aquifers, forests, and other ecosystems that store and release water. • The water issues in the Colorado basin contrast with the three principles because overextraction disrupts the natural process of the hydrologic cycle, the damming of the river has had negative impacts on biodiversity, and the control and movement of that volume of water is heavily dependent on energy inputs. Critical Thinking The following are examples of the material that should be contained in possible student answers to the end of chapter Critical Thinking questions. They represent only a summary overview and serve to highlight the core concepts that are addressed in the text. It should be anticipated that the students will provide more in-depth and detailed responses to the questions depending on an individual instructor’s stated expectations. 1. What do you believe are the three most important priorities for dealing with the water resource problems of the Colorado River Basin as discussed in the Core Case Study that opens this chapter? Explain your choices. Answer: Getting all the parties involved to attend a summit meeting to resolve the water issues of the region: (a) in a peaceful and nonviolent way, (b) to decide on regional conservation strategies, and (c) to develop cooperative agreements for future water sharing. 2. List three ways in which human activities are affecting the water cycle. How might these changes to the cycle affect your lifestyle? How might your lifestyle be contributing to these effects? Answer: (1) Overdrawing groundwater aquifers for increased agricultural irrigation. (2) Polluting freshwater streams, rivers, lakes, and the marine and oceanic provinces. (3) Alteration of the land surface of the earth and rising global temperatures are changing the frequency and severity of storms and drought in many parts of the world. This might affect my lifestyle with water shortages, and reduce my opportunities to enjoy the outdoors. My lifestyle might be affecting this by wasting water. 3. What role does population growth play in water supply problems? Relate this to water supply problems of the Colorado River Basin (Core Case Study). Answer: Population growth is at the root of many environmental problems and should be addressed as an urgent global problem. More people means that more water will be needed. None of these environmental problems, including meeting adequate water needs, can be addressed successfully until population growth is under control. The population centers that draw water from the Colorado River are not only large, but they are growing rapidly. In addition, this is a very agriculturally rich region that is heavily dependent upon irrigation. 4. Explain why you are for or against (a) raising the price of water while providing lower lifeline rates for the poor and lower middle class, (b) withdrawing government subsidies that provide farmers with water at low cost, and (c) providing government subsidies to farmers for improving irrigation efficiency. Answer: (a) Raising prices will better address the real costs involved in providing clean drinking water supplies for households. (b) Withdrawing subsidies would have the immediate effect of dramatically increasing food prices in areas that rely heavily on irrigation. Ultimately, market forces may drive agricultural enterprises to other regions where water is more readily available. Additionally, our most productive landscapes are places that are heavily irrigated, such as California. The public would need to be prepared for the inevitably rising prices that would follow this move. (c) Initially, the government could help with the costs for small farmers to implement better irrigation. Subsidies of this sort can help implement solutions that have a high up-front cost but large potential payback over time. 5. Calculate how many liters and gallons of water are wasted in 1 month by a toilet that leaks 2 drops of water per second. (1 liter of water equals about 3,500 drops and 1 liter equals 0.265 gallon.) How many bathtubs (containing about 151 liters or 40 gallons of water) could this wasted water fill? Answer: Given: Loss of water from leaking toilet. 2 drops of water per second 1 liter = 3,500 drops 1 liter = 0.265 gallons Calculation: Loss of water per month. 2 drops/s X 60 s/1 min X 60 min/1 h X 24 h/1 day X 7 days/1 week X 4 weeks/1 month = 4,838,400 drops/month ÷ 3,500 drops/liter = 1,382 liters/month X 0.265 gallons/ 1 liter = 366 gallons/month. This would fill just over 9 bathtubs (366 gallons/40 gallons per tub). 6. List the three most important ways in which you could reduce your unnecessary waste of water. Which, if any, of these things do you do? Answer: Use water saving fixture in the home Landscape with plants that require little water Water the garden with recycled grey water 7. List three ways in which human activities increase the harmful effects of flooding? What is the best way to prevent each of these human impacts? Do you think they should be prevented? Why or why not? Answer: Three things that humans have done to increase the harmful effects of flooding are the filling in of wetlands, the removal of woodlands, trees, and other ground-covering vegetation, and the channelization of streams so we could build and live in floodplains. These effects could be reduced by the preservation of forests/woodlands and watersheds; preserving and restoring wetlands in floodplains, and taxing any developments on floodplains, which ideally should be left undeveloped to enhance aquifer recharging and other sustainable natural processes. These human impacts should definitely be prevented because they severely alter the ecosystem processes of these aquatic systems and flooding often leads to loss of property and other damages. 8. List three ways you could apply Concept 13-6 (p. 334) to make your lifestyle more environmentally sustainable. Answer: (1) Use less water. (2) Work to protect aquifers, forests and ecosystems. (3) Learn more about water sources and limitations in your area. 9. Congratulations! You are in charge of the world. What are three actions you would take to (a) provide an adequate, safe drinking water supply for the poor and for other people in less-developed countries, (b) sharply reduce groundwater depletion, (c) sharply reduce water waste in irrigation, and (d) sharply reduce water waste in homes and businesses? Answer: (a) Take steps to prevent overdrawing of groundwater supplies, promote water conservation strategies in every sector of society; monitor and ensure strict water use allocations and reassess the cost of water for homes and businesses and provide subsidized rates or free supplies to low-income families. (b) Encourage drip irrigation on farms, put residential water use on a sliding scale, where customers pay more per unit the more they use, and educate the public about xeriscaping. (c) Irrigate with grey water, encourage polyculture or permaculture, and line irrigation canals to limit water loss. (d) subsidize water wise showerheads and faucets, encourage grey water use for irrigation, and put residential and business water use on a sliding scale, where customers pay more per unit the more they use 10. List two questions that you would like to have answered as a result of reading this chapter. Answer: 1. How can brands effectively adapt their strategies to different geographical boundaries and market segments? 2. What challenges do brands face when managing brand equity across different market segments? Ecological Footprint Analysis In 2005, the population of the U.S. state of Florida consumed 24.5 billion liters (6.5 billion gallons) of fresh water daily. It is projected that in 2025, the daily consumption will increase to 32.1 billion (8.5 billion gallons) per day. Between 2005 and 2025 the population of Florida is projected to increase from 17.5 million to 25.9 million. 1. Based on total fresh water use: (a) Calculate the per capita consumption of water per day in Florida in 2005 and the projected per capita consumption per day for 2025. (b) Calculate the per capita consumption of water per year in Florida in 2005 and the projected per capita consumption per year for 2025. 2. In 2005, how did the Florida average water footprint (consumption) per person per year, based only on water used within the state, compare with the average U.S. water footprint of approximately 2,490,600 liters (660,000 gallons) per person per year and the global average water footprint of 1,237,700 liters (328,000 gallons) per person per year? 1. Answer: Based on total fresh water use: 2. Answer: In 2005, the per capita annual water footprint (consumption) in Florida was less than the average national water footprint (Florida is 0.21 of the national average) and less than the global average water footprint (Florida is 0.41 of the global average). Instructors note: Since all of the food and products purchased in Florida are not grown or produced within the state, the water consumption figures do not truly reflect the total water footprint of the Florida population. Chapter 14 Geology and Nonrenewable Mineral Resources Summary 1. Tectonic plates have rearranged the earth’s continents and ocean basins over millions of years like pieces of a gigantic jigsaw puzzle. The plates have three types of boundaries. Natural hazards such as earthquakes and volcanoes are likely to be found at plate boundaries. 2. Rocks are large, natural, continuous parts of the earth’s crust. There are three major types of rocks: igneous, sedimentary, and metamorphic. Rocks are affected by changes of physical and chemical conditions that change them over time from one type to another through the rock cycle. 3. Mineral resources include all naturally occurring materials that are used for human purposes. These resources include metals and fossil fuels, and the distribution of these materials across the earth’s surface is highly variable leading to concentrated deposits in certain areas (e.g., diamonds in Angola or oil in Saudi Arabia). This unequal distribution can lead to conflicts and has implications for national security and international relations. 4. Mineral resource extraction methods include surface and subsurface mining. Surface mining types are open-pit, strip, contour strip mining, and mountain removal. Resource extraction technologies are constantly changing but always create some environmental disturbance. In some cases, the environmental impacts of mineral extraction can be severe. 5. All mineral resources are finite but the lifetime of materials varies with the rate of use and the size of the resource. Recycling of mineral resources leads to a longer depletion time compared to those that cannot be reused or recycled. 6. Scientists are developing new types of materials as substitutes for many metals. Mineral conservation and more sustainable manufacturing processes are helping to decrease our use and waste of such resources. Recent, dramatic increases in the cost of minerals are driving aggressive recycling of many resources and particularly metals (e.g., copper). Key Questions and Concepts 14-1 What are the earth’s major geological processes and hazards? CORE CASE STUDY: Gold extraction produces a tremendous amount of mining waste and can pollute the air and water. Cyanide is commonly used to extract gold and it is extremely toxic. In 2000 a cyanide leach pond was washed out in Romania, leading to environmental catastrophe downstream on the Tisza and Danube Rivers. A. The earth is made up of a core, mantle, and crust and is constantly changing as a result of processes taking place on and below its surface. Geology is the study of dynamic processes occurring on the earth’s surface and in its interior. B. Huge volumes of heated and molten rock moving around the earth’s interior form massive solid tectonic plates that move extremely slowly across the earth’s surface. About 12 or so rigid tectonic plates move across the surface of the mantle very slowly. These thick plates compose the lithosphere. C. The movement of these plates produces mountains on land and trenches on the ocean floor. The movement of plates also produces earthquakes and volcanic action. D. Some processes wear down the earth’s surface by moving topsoil and pieces of rock from one place to another, while other processes build up soil on the earth’s surface. Weathering is the physical, chemical, and biological processes that break down rocks and minerals into smaller pieces. E. Volcanoes often form along the boundaries of tectonic plates. Eruptions can be very destructive. F. Earthquakes are the release of energy accumulated over time along a fault. 1. Tsunamis can result from underwater earthquakes. 14-2 How are the earth’s rocks recycled? A. The earth’s crust consists of minerals and rocks. A rock is a combination of one or more minerals. 1. Sedimentary rock is made of sediment. 2. Igneous rock forms below the earth’s surface. 3. Metamorphic rock forms when preexisting rocks are subjected to high temperatures or pressure. 4. The rock cycle is the interaction of physical and chemical. 14-3 What are mineral resources and what are the environmental effects of using them? A. Mineral resources are concentrations of naturally occurring materials that can be extracted and processed. 1. Ore is a rock with a high concentration of a particular mineral. Can be high-grade, or low-grade. 2. Reserves of minerals are identified resources from which the mineral can be extracted profitably. B. The life cycle of a metal is very energy intensive. C. There are many ways to extract minerals 1. Surface mining 2. Open pit mining 3. Strip mining 4. Contour strip mining 5. Mountaintop removal 6. Subsurface mining a. Identified resources have a known location, quantity, and quality. b. Reserves are identified resources that can be extracted profitably at current prices. c. Undiscovered reserves are potential supplies of a mineral resource assumed to exist. d. Other resources are undiscovered resources and identified resources not classified as reserves. D. Mining scars the land and produces large amounts of solid waste and air and water pollution. The impacts include high costs (into the billions of dollars), subsidence, toxin and acid drainage, toxics emission to the atmosphere. E. After waste material is removed from metal ores they are smelted or treated with chemicals to extract the desired metal. There can be enormous amounts of air and water pollution from these processes. 14-4 How long will supplies of nonrenewable mineral resources last? A. The future supply of a resource depends on its affordable supply and how rapidly that supply is used. A nonrenewable resource generally becomes economically depleted rather than totally depleted. There are five choices at that point: recycle or reuse existing supplies, waste less, use less, find a substitute, or do without. B. A rising price for a scarce mineral resource can increase supplies and encourage more efficient use. Economics determines what part of a known mineral supply is extracted and used. Higher prices often mean more resources can be used (at a higher extraction cost), but this can be affected by national policies that subsidize exploration or restrict exports/imports. CASE STUDY: The US General Mining Law of 1872 was designed to encourage hard rock mining on public lands. Many people have become wealthy by exploiting this law for mining and to other ends. Cleaning up degraded land and streams has cost taxpayers large sums of money. Critics call for tighter environmental controls and higher royalties to be paid by the mining companies. C. New technologies can increase the mining of low-grade ores at affordable prices, but harmful environmental effects can limit this approach. In 1900, the average copper ore mined in the U.S. was about 5% copper by weight; today that ratio is 0.5%. D. Most minerals in seawater and on the deep ocean floor cost too much to extract, and there are squabbles over who owns them. Rich hydrothermal deposits of gold, silver, zinc, and copper are found as sulfide deposits in the deep-ocean floor and around hydrothermal vents. Another potential source from the ocean floor is potato-sized manganese nodules that cover large areas of ocean floor. 14-5 How can we use mineral resources more sustainably? A. Scientists and engineers are developing new types of materials that can serve as substitutes for many metals. This is known as the materials revolution. For example, development of silicon and ceramics may replace the need for as much metal. B. Recycling valuable and scarce metals saves money and has a lower environmental impact than mining and extracting them from their ores. In many cases, metals are actively recycled. C. We can use mineral resources more sustainably by reducing their use and waste and by finding substitutes with fewer harmful environmental effects. SCIENCE FOCUS: Nanotechnology involves the manipulation of atoms and molecules to create materials. The technology is very promising, but there are drawbacks. It is suggested that we carefully investigate risks and develop guidelines and regulations until more is known about potentially harmful effects. CASE STUDY: 3M is a company that has used waste prevention as means of attaining cleaner production. . Teaching Tips: Large Lecture Classes: Start class with a question about resource availability. Using clickers or work in class, ask the students how long the world’s copper supply will last. Tell them there are reserves of 470,000 metric tons and current use is about 14,000 metric tons per year (numbers are from the USGS minerals report). As needed, introduce the concept of residence/turnover time (e.g., reserve/use rate). Answer is about 33 years at constant rate of use. Ask if there is anything wrong with this calculation—global use of copper increased by 16% in 2003 (mostly due to demand in China)—ask what this would do to the calculation. Smaller Lecture Classes: Use an exercise similar to the one above but use information from the USGS commodity summaries (http://minerals.usgs.gov/minerals/pubs/mcs/). Have students break into groups and calculate potential lifetimes for a range of minerals. Many will be relatively short (decades), so use this to start a discussion about use of resources and obligation (e.g., values?) to find new sources, replacements, or recycling opportunities. Key Terms area strip mining asthenosphere contour strip mining core crust depletion time earthquake geology high-grade ore igneous rock lithosphere low-grade ore mantle metamorphic rock mineral mineral resource mountaintop removal open-pit mining ore overburden reserves rock rock cycle sedimentary rock smelting spoils strip mining subsurface mining surface mining tectonic plates tsunami volcano weathering Term Paper Research Topics 1. Geologic processes: plate tectonics, geologic hazards. How do these processes work? 2. Resource demands: the commodities market; aluminum industry in the United States; steel alloys; industrial use of chromium and other strategic minerals. 3. Mining processes: manganese-rich nodule mining methods; Frasch process sulfur mining; improved technology for mining low-grade ore. 4. Mining and the environment: modern surface mining reclamation methods; surface mining and the acid runoff problem; smelting and air pollution problems. 5. Experts are concerned about the availability of four strategic metal resources (manganese, cobalt, chromium, and platinum) that are essential for the country’s economic and military strength. Why are these metals particularly important? 6. Should we build in earthquake zones? If earthquakes occur, should we rebuild and who should pay for it? 7. Should mineral-rich but underexplored Antarctica be opened to mineral exploration and development without delay? 8. Should seabed mineral deposits such as manganese-rich nodules be declared an ecosphere resource to which landlocked, less-developed nations may rightfully stake a fair share claim? 9. Can and should we mine asteroids? 10. Evaluate the use of metals in the U.S. How much of U.S. supply is provided by imports? What are the strategic implications of this? What are the environmental implications? Discussion topics 1. Who should have access to a country’s metals—is the free market the best way to decide how metals are distributed? Answer: Access to a country's metals can be governed by a combination of free market dynamics and government regulations. While the free market can efficiently allocate resources based on supply and demand, government intervention may be necessary to ensure strategic reserves, environmental protection, and equitable access. The best approach balances economic efficiency with national security and sustainability considerations. 2. What are the implications of finite mineral supplies? How should we address impending shortages? Answer: Finite mineral supplies pose significant challenges, including potential scarcity, increased prices, and geopolitical tensions. To address impending shortages, we should focus on sustainable mining practices, recycling, developing alternative materials, and investing in research for new resource extraction technologies. Diversifying supply sources and improving resource efficiency are also crucial strategies. 3. How can we replace common materials (e.g., copper or steel)? What are the tradeoffs in doing so? Answer: Replacing common materials like copper or steel involves developing and adopting alternatives such as aluminum, plastics, or composites. Tradeoffs include differences in cost, performance, environmental impact, and recyclability. For example, aluminum is lighter and more corrosion-resistant than steel but may have higher production costs. The choice of replacement materials depends on balancing these tradeoffs with specific application requirements. 4. Take several resources (good ones are oil, coal, iron, and phosphorus) and several countries (US, China, Japan) and ask the class to examine how unequal distribution of these resources might affect the future growth of these three countries. Answer: Unequal distribution of resources like oil, coal, iron, and phosphorus can significantly impact the economic growth and energy security of countries. The U.S. and China, with abundant coal and oil reserves, may benefit from energy independence, while Japan, with limited resources, relies heavily on imports, affecting its energy costs and industrial competitiveness. Future growth in these countries may depend on their ability to secure resources, invest in alternatives, and develop efficient technologies. 5. Discuss examples of superfund sites related to historical mining. Have a discussion of who should bear the costs for cleanup of these contaminated sites. Answer: Superfund sites like the Berkeley Pit in Montana and the Tar Creek site in Oklahoma highlight the environmental damage from historical mining. The responsibility for cleanup costs is a contentious issue, typically involving the companies responsible for the contamination, government agencies, and taxpayers. The principle of "polluter pays" suggests that the companies should bear the primary costs, but public funds may also be necessary when responsible parties cannot be held accountable or lack sufficient resources. Activities and Projects 1. Have the class watch the movie “Blood Diamond” prior to a class session. Use this movie as a starting point for a discussion of the ethics of resource extraction. 2. Invite a geologist to your class to discuss the local topography and the rock and mineral content of nearby soils. 3. Take a class field trip to a superfund site nearby. 4. As a class exercise, discuss the economic, political, social, and environmental consequences that might ensue if a new mineral resource was found in your area. 5. With your class, visit several construction sites in your locale. Look for evidence of human-accelerated soil erosion and methods or practices employed to minimize it. 6. Have your students find poems, songs, or paintings that express intense human feelings about mining the land and the lifestyles of a mining community during the past several hundred years. Discuss how such mining operations have changed over time. 7. Ask a seismologist to visit the class and discuss the stability of the tectonic plate that you live on. 8. Are any surface mining operations taking place in your vicinity? If so, arrange for a spokesperson to explain how the mining company complies with the specifications of the Surface Mining Control and Reclamation Act. 9. Invite a toxicologist to visit your class and discuss the problem of metal toxicity. 10. Invite a representative from a local industry to visit the class and describe what Eco industrial initiatives are being adopted by the company. Attitudes and Values 1. Three countries (the United States, Canada, and Russia) with only 8% of the world’s population consume about 75% of the world’s most widely used metals. Is this fair? Answer: The disparity in metal consumption raises questions of fairness and equity, highlighting the global inequality in resource use. While it may reflect economic and industrial development, it also underscores the need for more sustainable and equitable resource distribution. Addressing this imbalance requires international cooperation, resource-sharing agreements, and promoting sustainable consumption practices worldwide. 2. What kinds of risks from the natural environment occur in your area? Who is responsible for protecting citizens from these risks? Answer: Natural environmental risks vary by location and can include earthquakes, floods, hurricanes, wildfires, and more. Local and regional governments typically bear the primary responsibility for protecting citizens from these risks through zoning laws, emergency preparedness plans, infrastructure improvements, and public education. Additionally, federal agencies often provide support and resources for disaster response and mitigation. 3. Would you support policies that discourage human development in areas where natural hazards are most likely to occur? If so, how far should government go to enforce these policies? Answer: Supporting policies that discourage development in hazard-prone areas is essential for minimizing risk and protecting lives and property. Governments should enforce these policies through regulations, zoning laws, and building codes. While these measures should be firm, they must also consider socio-economic factors, offering incentives for relocation or adaptation and ensuring fair compensation for affected property owners. 4. Do you think new technologies will enable us to reduce use of non-renewable resources? If you do think so, then how much responsibility do we have to reduce consumption today and how should that be balanced against future potential technological improvements? Answer: New technologies, such as renewable energy, energy-efficient materials, and recycling innovations, hold promise for reducing reliance on non-renewable resources. However, we still have a significant responsibility to reduce consumption today to mitigate environmental impact and preserve resources for future generations. This responsibility should be balanced by investing in and promoting technological advancements while encouraging sustainable consumption and conservation practices now. News Videos Does Clean Coal Exist? The Brooks/Cole Environmental Science Video Library, 2009; DVD 0538733551 Additional Video Resources Oil on Ice (Documentary, 2004) Arctic National Wildlife Refuge and Drilling for Oil. http://www.oilonice.org/ Earth Revealed: Birth of a Theory and Plate Dynamics (Annenberg Video on Demand) http://www.learner.org/index.html Savage Earth (PBS series) http://www.pbs.org/wnet/savageearth/earthquakes/ U.S. Mining Law Contested (Short Documentary, 2008) A six-minute National Geographic video discusses the controversy of modern applications of the 1872 mining law. http://news.nationalgeographic.com/news/2008/02/080201-hardrock-video-wc.html Black Diamonds (Documentary, 2005) Mountain top removal and mining in the Appalachian Mountains. http://www.blackdiamondsmovie.com/ Web Resources US Geological Survey USGS global mineral use report. http://minerals.usgs.gov/minerals/pubs/mcs/ Canadian Geologic Survey Global resource distribution and global geologic maps. http://gsc.nrcan.gc.ca/wmgdb/images_e.php. Earth Works Environmental group’s website showing mining impacts. http://www.earthworksaction.org/EnvironmentalImpacts.cfm World Coal Institute Coal trade association’s page about the environmental impacts of coal. http://www.worldcoal.org/pages/content/index.asp?PageID=126 Suggested Responses to End of Chapter Questions Review Questions 1. Review the Key Questions and Concepts for this chapter on p. 347. Describe some environmental effects of gold mining (Core Case Study). Answer: • Gold miners remove large amounts of rock; extracting enough gold for two rings created about 5.5 metric tons mining waste which is left piled near mine sites and can pollute the air and nearby surface water. One mining technology called cyanide heap leaching is used by mining companies to level entire mountains of rock containing only small concentrations of gold. To extract the gold, miners spray a solution of highly toxic cyanide salts onto huge open- air piles of crushed rock. The solution then drains into storage ponds. This cyanide is extremely toxic to birds and mammals drawn to these ponds in search of water. The ponds can also leak or overflow, posing threats to underground drinking water supplies and fish and other forms of life in nearby lakes and streams. 2. Define geology. Define and distinguish among core, mantle, crust, asthenosphere, and lithosphere. Define tectonic plates and explain how they were likely formed. Distinguish between a subduction zone and a transform fault. What is weathering and why is it important? Define volcano and describe the nature and effects of a volcanic eruption. Define earthquake and define its nature and effects. What is a tsunami and what are its effects? Answer: • Geology is the science devoted to the study of dynamic processes occurring on the earth’s surface and in its interior. • The core is the earth’s innermost zone. It is extremely hot and has a solid inner part, surrounded by a liquid core of molten or semisolid material. • Surrounding the core is a thick zone called the mantle, mostly solid rock. • The outermost and thinnest zone of the earth is the crust. • The asthenosphere is a zone of hot, partly melted rock under the rigid outermost part of the mantle. • The combination of the crust and the rigid, outermost part of the mantle is called the lithosphere. • Tectonic plates are huge rigid plates that move extremely slowly atop the denser mantle. They were likely formed from the flows of energy and heated material in convection cells that caused the lithosphere to break up. • Tectonic plates can also slide and grind past one another along a fracture (fault) in the lithosphere—a type of boundary called a transform fault. It consists of the continental crust, which underlies the continents (including the continental shelves extending into the oceans), and the oceanic crust, which underlies the ocean basins and makes up 71% of the earth’s crust. Subduction is when an oceanic plate collides with a continental plate. The continental plate usually rides up over the denser oceanic plate and pushes it down into the mantle. The area where this collision and subduction takes place is called a subduction zone. • Weathering is the physical, chemical, and biological processes that break down rocks into smaller particles that help build soil. Weathering plays a key role in soil formation. • A volcano is created when magma in the partially molten asthenosphere rises in a plume through the lithosphere to erupt on the surface as lava, which builds a cone. Sometimes, internal pressure is high enough to cause lava, ash, and gases to be ejected into the atmosphere or to flow over land, causing considerable damage. • Forces inside the earth’s mantle and near its surface push, deform, and stress rocks. The stress can cause the rocks to suddenly shift or break and produce a transform fault, or fracture, in the earth’s crust. When a fault forms, or when there is abrupt movement on an existing fault, energy that has accumulated over time is released in the form of vibrations, called seismic waves, which move in all directions through the surrounding rock. This internal geological process is called an earthquake. Most earthquakes occur at the boundaries of tectonic plates when colliding plates create tremendous pressures in the earth’s crust or when plates slide past one another at transform faults. Relief of the earth’s internal stress releases energy as shock (seismic) waves, which move outward from the earthquake’s focus like ripples in a pool of water. Scientists measure the severity of an earthquake by the magnitude of its seismic waves. • A tsunami is a series of large waves generated when part of the ocean floor suddenly rises or drops. Most large tsunamis are caused when certain types of faults in the ocean floor move up or down as a result of a large underwater earthquake, a landslide caused by such an earthquake, or in some cases by a volcanic eruption. Tsunamis are often called tidal waves, although they have nothing to do with tides. They can travel far across the ocean at the speed of a jet plane. In deep water the waves are very far apart and their crests are not very high. As a tsunami approaches a coast, it slows down, its wave crests squeeze closer together, and their heights grow rapidly. It can hit a coast as a series of towering walls of water that can level buildings. 3. Define mineral, rock, sedimentary rock, igneous rock, and metamorphic rock and give an example of each. Define and explain the importance of the rock cycle. Answer: • A mineral is an element or inorganic compound that occurs naturally in the earth’s crust as a solid with a regular internal crystalline structure. • Rock is a solid combination of one or more minerals found in the earth’s crust. Some kinds of rock, such as limestone and quartzite, contain only one mineral. • Sedimentary rock is made of sediments—dead plant and animal remains and tiny particles of weathered and eroded rocks. Examples include sandstone, shale, dolomite, limestone, lignite and bituminous coal. • Igneous rock forms below or on the earth’s surface when magma wells up from the earth’s upper mantle or deep crust and then cools and hardens. Examples include granite and lava rock. • Metamorphic rock forms when a preexisting rock is subjected to high temperatures, high pressures, chemically active fluids, or a combination of these agents. Examples include slate and marble. • The interaction of physical and chemical processes that change rocks from one type to another is called the rock cycle. In this process, rocks are broken down, eroded, crushed, heated, melted, fused together into new forms by heat and pressure, cooled, and/ or recrystallized within the earth’s mantle and in the earth’s crust. The rock cycle concentrates the planet’s nonrenewable mineral resources on which our life processes depend. 4. Define mineral resource and list two major types of such resources. Describe three uses of rock as a resource. Define ore and distinguish between a high-grade ore and a low- grade ore. What are reserves? Describe the life cycle of a metal resource. Describe three major harmful environmental effects of extracting, processing, and using nonrenewable mineral resources. Answer: • A mineral resource is a concentration of naturally occurring material from the earth’s crust that can be extracted and processed into useful products and raw materials at an affordable cost. Two major types are metallic minerals (such as aluminum and gold), and nonmetallic minerals (such as sand and limestone). Because they take so long to form, minerals are classified as nonrenewable resources. • Some uses include making steel, glass and concrete. • An ore is rock that contains a large enough concentration of a particular mineral—often a metal—to make it profitable for mining and processing. A high-grade ore contains a large concentration of the desired mineral, whereas a low-grade ore contains a smaller concentration. • Reserves are identified resources from which the mineral can be extracted profitably at current prices. • See Figure 14-11. Life cycle of a metal resource. • See Figure 14-12. Some harmful environmental effects of extracting, processing, and using nonrenewable mineral and energy resources. Mining, processing, and using mineral resources take enormous amounts of energy and can disturb the land, erode soil, produce solid waste, and pollute the air, water, and soil. 5. What is surface mining? Define overburden, spoils, and open-pit mining. Define strip mining and distinguish among area strip mining, contour strip mining, and mountaintop removal mining. What is subsurface mining? Describe three harmful environmental effects of mining. What is smelting and what are its major harmful environmental effects? Answer: • Shallow mineral deposits are removed by surface mining, in which materials lying over a deposit are removed to expose the resource for processing. • Overburden is the soil and rock overlying a useful mineral deposit. Overburden is usually set aside in piles of waste material, called spoils. • In open-pit mining, machines dig very large holes and remove ores, sand, gravel, and stone such as limestone and marble. • Strip mining is useful and economical for extracting mineral deposits that lie in large horizontal beds close to the earth’s surface. There are several types of strip mining. ○ In area strip mining, used where the terrain is fairly flat, a gigantic earthmover strips away the overburden, and a power shovel removes the mineral deposit. ○ Contour strip mining is used mostly to mine coal on hilly or mountainous terrain. A huge power shovel cuts a series of terraces into the side of a hill. Colossal earthmovers remove the overburden, a power shovel extracts the coal, and the overburden from each new terrace is dumped onto the one below. ○ Another surface mining method is mountaintop removal. In the Appalachian Mountains of the United States, where this form of mining is prominent, explosives, large power shovels, and huge machines, called draglines, are used to remove the top of a mountain and expose seams of coal, which are then removed. • Deep deposits of minerals are removed by subsurface mining, in which mineral resources are removed from underground through tunnels and shafts. • See Figure 14-12: Some harmful environmental effects of extracting, processing, and using nonrenewable mineral and energy resources. • Heating ores to release metals is called smelting. Without effective pollution control equipment, smelters emit enormous quantities of air pollutants, including sulfur dioxide and suspended particles, which damage vegetation and acidify soils in the surrounding area. Smelters also cause water pollution and produce liquid and solid hazardous wastes that require safe disposal. 6. What five nations supply most of the world’s nonrenewable mineral resources? How dependent is the United States on other countries for important nonrenewable mineral resources, including strategic metals? Define depletion time and describe three types of depletion curves for a mineral resource. Answer: • Five nations—the United States, Canada, Russia, South Africa, and Australia—supply most of the nonrenewable mineral resources used by modern societies. • Currently, the United States imports all of its supplies of 20 key nonrenewable mineral resources and more than 90% of its supplies of 4 other key minerals. The United States has little or no reserves of manganese, cobalt, chromium, and platinum, all of which are strategic metal resources. • Depletion time is the time it takes to use up a certain proportion— usually 80%— of the reserves of a mineral at a given rate of use. The shortest depletion time estimate assumes no recycling or reuse and no increase in reserves. A longer depletion time estimate assumes that recycling will stretch existing reserves and that better mining technology, higher prices, or new discoveries will increase reserves. An even longer depletion time assumes that new discoveries will further expand. 7. Describe the conventional view of the relationship between the supply of a mineral resource and its market price. What are five effects of a mineral becoming scarce? Discuss the pros and cons of the U. S. General Mining Law of 1872. Answer: • According to standard economic theory, in a competitive market system, a plentiful mineral resource is cheap when its supply exceeds demand. When a resource becomes scarce, its price rises. According to some economists, this price effect may no longer apply very well in most developed countries. Industry and government in such countries often use subsidies, taxes, regulations, and import tariffs to control the supplies, demands, and prices of minerals to such an extent that a truly competitive market does not exist. Most mineral prices are kept artificially low because governments subsidize development of their domestic mineral resources to help promote economic growth and national security. • Scarcity can lead to higher prices, encourage new exploration, stimulate development of new technologies, make lower-grade ores profitable, and encourage substitutes or resource conservation. • The U. S. General Mining Law of 1872 was designed to encourage mineral exploration and the mining of hard-rock minerals ( such as gold, silver, copper, zinc, nickel, and uranium) on U. S. public lands and to help develop the then- sparsely populated West. Until 1995 when a freeze on such land transfers was declared by Congress, one could pay the federal government $ 2.50– 5.00 an acre) for land owned jointly by all U. S. citizens. One could then lease the land, build on it, sell it, or use it for essentially any purpose. People have constructed golf courses, hunting lodges, hotels, and housing subdivisions on public land that they bought from taxpayers at 1872 prices. Mining companies point out that they must invest large sums to locate and develop an ore site before they make any profits from mining hard- rock minerals. They argue that government subsidized land costs allow them to provide high-paying jobs to miners, supply vital resources for industry, stimulate the national and local economies, reduce trade deficits, and keep mineral products affordable. Critics argue that the money taxpayers give up as subsidies to mining companies offsets the lower prices they pay for these products. 8. Describe the opportunities and limitations of increasing mineral supplies by mining lower-grade ores. What are the advantages and disadvantages of biomining? Describe the opportunities and limitations of getting more minerals from the ocean. Answer: • Some analysts say we can increase supplies of a mineral by extracting lower grades of ore. They point to the development of new earth-moving equipment, improved techniques for removing impurities from ores, and other technological advances in mineral extraction and processing. Such advancements have made it possible to extract some lower-grades ores and even to reduce their costs. Several factors can limit the mining of lower- grade ores. One is the increased cost of mining and processing larger volumes of ore. Another is the limited availability of freshwater needed to mine and process some minerals. A third limiting factor is the environmental impacts of the increased land disruption, waste material, and pollution produced during mining and processing. • Using microorganisms to extract mineral, or biomining, removes desired metals from ores through wells bored into the deposits. It leaves the surrounding environment undisturbed and reduces the air pollution associated with the smelting of metal ores. It also reduces hazardous chemical water pollution such as that resulting from the use of cyanide and mercury in gold mining. However, biomining can take decades to remove the same amount of material that conventional methods can remove within months or years. So far, biological min-ing methods are economically feasible only with low-grade ores for which conventional techniques are too expensive. • Some ocean mineral resources are dissolved in seawater. However, most of the chemical elements found in seawater occur in such low concentrations that recovering these mineral resources takes more energy and money than they are worth. Currently, only magnesium, bromine, and sodium chloride are abundant enough to be extracted profitably. 9. Describe the opportunities and limitations of finding substitutes for scarce mineral resources. How could nanotechnology affect the search for substitutes, and how might it affect the mining industry? What are some possible problems that could arise from the growing use of nanotechnology? Describe the benefits of recycling and reusing valuable metals. List five ways to use nonrenewable mineral resources more sustainably. Describe the Pollution Prevention Pays program of the Minnesota Mining and Manufacturing Company. Describe 3M Company’s Pollution Prevention Pays program. Answer: • Some analysts believe that human ingenuity will find substitutes for key minerals. They point to nanotechnology and to the current materials revolution in which silicon and new materials, particularly ceramics and plastics, are being used as replacements for metals. Plastic has replaced copper, steel, and lead in much piping. Fiber-optic glass cables that transmit pulses of light are replacing copper and aluminum wires in telephone cables. However, use of plastics has drawbacks, chief of which is that making them by current methods requires the use of oil and other fossil fuels. Substitution is not a cure- all. For example, currently, platinum is unrivaled as an industrial catalyst, and chromium is an essential ingredient of stainless steel. We can try to find substitutes for scarce resources but this may not always be possible. • Scientists plan to use atoms of abundant substances such as carbon, silicon, silver, titanium, and boron as building blocks to create an immense array of products, effectively diminishing the importance of the mining industry. • Nanotechnology is potentially problematic because as particles get smaller they become more reactive and potentially more toxic to humans and other animals. • The benefits of recycling and reuse include less energy use, less air pollution, and less water pollution. • Ways to achieve more sustainable use of nonrenewable mineral resources include: ○ Do not waste mineral resources. ○ Recycle and reuse 60–80% of mineral resources. ○ Include the harmful environmental costs of mining and processing minerals in the prices of items (full-cost pricing). ○ Reduce mining subsidies. ○ Increase subsidies for recycling, reuse, and finding substitutes. ○ Redesign manufacturing processes to use less mineral resources and to produce less pollution and waste (cleaner production). ○ Use mineral resource wastes of one manufacturing process as raw materials for other processes. ○ Slow population growth. • In 1975, the U.S.-based Minnesota Mining and Manufacturing Company began a Pollution Prevention Pays program. It redesigned its equipment and processes, used fewer hazardous raw materials, identified toxic chemical outputs (and recycled or sold them as raw materials to other companies), and began making more nonpolluting products. By 2008, 3M had prevented 1.4 million metric tons for pollutants from reaching the environment. The company had saved more than $1.2 billion in waste disposal and material costs. 10. What are the three big ideas of this chapter? Describe how we can apply the three principles of sustainability in order to obtain and use nonrenewable mineral resources in a more sustainable way. Answer: • The three big ideas are: ○ Dynamic forces that move matter within the earth and on its surface recycle the earth’s rocks, form deposits of mineral resources, and cause volcanic eruptions, earthquakes, and tsunamis. ○ The available supply of a mineral resource depends on how much of it is in the earth’s crust, how fast we use it, mining technology, market prices, and the harmful environmental effects of removing and using it. ○ We can use mineral resources more sustainably by trying to find substitutes for scarce resources, reducing resource waste, and reusing and recycling nonrenewable minerals. • Mineral resources should not be extracted more rapidly natural cycles can replenish them, they should not be extracted in a way that compromises the health or survival of humans or other species, and the energy used in making materials should be minimized or provided solely by the sun. Mineral resources should be recycled and reused as much as possible. Critical Thinking The following are examples of the material that should be contained in possible student answers to the end of chapter Critical Thinking questions. They represent only a summary overview and serve to highlight the core concepts that are addressed in the text. It should be anticipated that the students will provide more in-depth and detailed responses to the questions depending on an individual instructor’s stated expectations. 1. List three ways in which you could apply Concept 14-5 to making your lifestyle more environmentally sustainable. Answer: (1) Recycle. (2) Find substitutes for or go without scarce materials. (3) Reduce waste. 2. List three ways in which decreasing the need to mine gold and reducing its harmful environmental effects (Core Case Study) could benefit you. Answer: (1) Reduce water pollution in parts of the world affected by gold mining. (2) Reduce the impacts of gold mining on bird and animal life. (3) Save money from buying unnecessary gold jewelry. 3. What do you think would happen if the earth’s tectonic plates stopped moving? Explain. Answer: Without plate tectonics our world would not be what it is today. If plate tectonics were to come to a sudden halt, our geographical shape would not change because there would be no more shifting of plates, which cause earthquakes, mountain ranges, and volcanoes. Without plate tectonics the recycling of the planet’s mineral resources would be devastated because there would be no more mineral deposits, which help sustain life. The richness in our soil nutrients would be greatly affected because of the lack of natural recycling, for example the volcanic lava that helps to make soils rich. The atmosphere may also be at risk because volcanic eruptions have helped to form the atmosphere. 4. You are an igneous rock. Write a report on what you experience as you move through the rock cycle (Figure 14-10). Repeat this exercise, assuming you are a sedimentary rock and then a metamorphic rock. Answer: As an igneous rock, I begin my journey deep below the surface of the earth in a hot and molten state called magma. As I move up through the upper mantle, I cool and harden and form granite. I can also take another turn on my journey, and if I erupt out of the earth, rather than cool beneath it, I become lava rock and cool and harden into pumice or basalt. As a sedimentary rock, I begin my journey as a large rock and then get broken down into smaller pieces that can be transported by water, wind, or gravity. I then get deposited in layers that accumulate over time and through pressure become larger rocks once again, such as sandstone or shale. Sometime I can form dolomite or limestone if I come from compacted shells, or lignite or bituminous coal if I am derived from plants. As a metamorphic rock, I can get subjected to high temperatures and pressures, transforming my crystal structure into anthracite coal, slate, or marble. 5. Use the second law of thermodynamics (See chapter 2, p. 47) to analyze the scientific and economic feasibility of each of the following processes: a. Extracting most of the minerals dissolved in seawater, b. Mining increasingly lower-grade deposits of minerals, c. Using inexhaustible solar energy to mine minerals, d. Continuing to mine, use, and recycle minerals at increasing rates. Answer: The second law of thermodynamics states that whenever energy changes from one form to another, we always end up with less usable energy than we started with. (a) This is impracticable because the minerals dissolved in seawater are there in such small amounts that we would need to use vast amounts of energy to evaporate large quantities of seawater to obtain small amounts of minerals. (b) Again this is impractical because we would be expending ever-increasing amounts of energy to obtain smaller and smaller amounts of minerals from the lower-grade deposits. (c) This would be economically feasible if it could be established. The sun is in essence a never-ending supply of “free” energy that could be harnessed for mineral extraction purposes. We would still be undergoing a process governed by the second law, but as we had an inexhaustible energy supply in the first place, it would overall be a feasible idea. (d) This option is not feasible. If we continue to use mineral resources at ever increasing rates, we will eventually run out as we would be mining lower and lower-grade ores and getting less bang for the buck. Even if we recycled more there are still energy considerations to be taken into account in producing the new materials. The best thing to do would be to reuse things as often as possible and, even better, ask yourself whether you need the thing in the first place. 6. Explain why you support or oppose each of the following proposals concerning extraction of hard-rock minerals on public land in the United States (see Case Study, p. 362): (a) halting the practice of granting title to public land for actual or claimed Hardrock mineral deposits, (b) requiring mining companies to pay a royalty of 8–12% on the gross income they earn from hard-rock minerals that they extract from public lands, and (c) making hard-rock mining companies legally responsible for restoring the land and cleaning up environmental damage caused by their activities. Answer: Most of the reasons to support these proposals have to do with reducing the impact of mining on a public resource (land to be used for multiple purposes). All three proposals could reduce impacts significantly or, in the case of proposal c, aid in the restoration of lands degraded by mining activities. Reason to oppose these proposals mostly revolve around costs to the mining companies and the potential to restrict economic activity. 7. Suppose you were told that mining deep ocean mineral resources would mean severely degrading ocean-bottom habitats and life-forms such as giant tube worms and giant clams. Do you think that this information should prevent or put an end to such ocean-bottom mining? Explain. Answer: This information is definitely worthy of putting a stop to mining deep ocean resources, as it is detrimental to biodiversity and causes habitat destruction. Our lack of knowledge about the biodiversity at the bottom of the oceans should invoke the precautionary principle to halt such activities. Unfortunately, our deep oceans are so remote that they are off the radar for most people, and it is in such places that a lot of environmental damage can occur without anyone taking notice. 8. List three ways in which a nanotechnology revolution (Science Focus, p. 365) could benefit you and three ways in which it could harm you. Answer: Three positive ways that nanotechnology could benefit me would be that soil, air, and groundwater could be cleaned of industrial pollutants. Another positive effect would be an affordable way to purify water. A third positive effect would be the ability to design nano molecules that could search and kill only cancer cells. Even though nanotechnology seems very positive, it can have negative effects because of the small size of the particles; they could be potentially toxic to humans and animals. The tiny size of nanoparticles means they can penetrate deeply into our lungs and respiratory system. Our whole body could be at risk because they can be absorbed into the blood stream. They could also have a negative effect on the function of our cell membranes. 9. Congratulations! You are in charge of the world. What are the three most important features of your policy for developing and sustaining the world’s nonrenewable mineral resources? Answer: The three most important features of a policy to develop and sustain the world’s nonrenewable mineral resources would be to reuse, recycle, and reduce consumption. These three features would be ubiquitous throughout the policy. 10. List two questions that you would like to have answered as a result of reading this chapter. Answer: 1. How can brands maintain consistent brand equity in new markets? 2. What strategies can brands use to target diverse segments? Data Analysis Uranium (U), is a mineral resource obtained from uranium ore deposits in various types of rock at different concentrations. It is used as fuel in the reactors of nuclear power plants. A high-grade ore has 2% U and a low-grade ore has 0.1% U. The estimated worldwide recoverable resources of uranium weigh 4,743,000 metric tons. The United States has about 7% of the world’s uranium resources, which amounts to about 342,000 metric tons. 1. Given that current worldwide usage of uranium is about 66,500 U/year, how long will the world’s present recoverable resources last? (Note: 1 metric ton 1 tone = 1,000 kg = 1.1 tons) 2. Assume U.S. usage is about 25% of world usage. If the U.S. were to rely just only on its domestic uranium resources, how long would they last, assuming a 100% recovery rate (meaning that 100% of the resource can be used)? 3. Assume that most U.S. ore bodies contain high-grade ore (2% U) and that the recovery rates of uranium from the ore (accounting for losses in mining, extraction, and refining) average 65%. How many metric tons of ore will have to be mined to meet U.S. needs? 1. Answer: 4,743,000 metric tons /66,500 metric tons/year = 71.3 years 2. Answer: 342,000 metric tons/(0.25 x 66,500 metric tons ) = 20.6 years 3. Answer: Annual U.S. needs = 25% x Worldwide use = 0.25 x 66,500 metric tons U/year = 16,625 metric tons U/year With ore of 2% U and 65% recovery, required ore = 16,625 metric tons U/year/0.65/0.02 = 1.28 million metric ton per year Solution Manual for Living in the Environment: Principles, Connections, and Solutions G. Tyler Miller, Scott Spoolman 9780538735346