This Document Contains Chapters 9 to 11 Chapter 9 Nonrenewable Energy Resources Summary and Objectives 9-1 What is net energy and why is it important? The sun provides an essentially inexhaustible supply of solar capital, providing nearly all the energy that heats the earth and our buildings. Commercial energy comes primarily from fossil fuels (79%), because they are abundant, transportable, and cheap. CONCEPT 9-1 Energy resources vary greatly in their net energy yields -- the amount of high-quality energy available from an energy resource minus the amount of energy needed to make it available. 1. With what criteria should energy resources be evaluated? 2. What is the significance of the concept of net energy? 9-2 What are the advantages and disadvantages of using oil? The United States uses 23% of global oil production, while only having 1.5% of proven global oil reserves. The U.S. economy and many others in the developed world depend on inexpensive oil supplies. The growing demand in the U.S. cannot be met by increasing domestic supplies. CONCEPT 9-2A Conventional crude oil is abundant and has a medium net energy yield, but using it causes air and water pollution and releases greenhouse gases to the atmosphere. CONCEPT 9-2B Unconventional heavy oil from oil shale rock and tar sands exists in potentially large supplies but has a low net energy yield and a higher environmental impact than conventional oil has. 3. What are several products we obtain from refining crude oil? 4. Why is petroleum useful as an energy resource? What are the disadvantages? 5. Distinguish between shale oil and tar sands. Despite their large worldwide reserves, these are not good choices for supplying the world's oil. Why? 9-3 What are the advantages and disadvantages of using natural gas? Conventional natural gas is found above most reservoirs of crude oil. Natural gas is a versatile fuel, yet it has a high transportation costs. CONCEPT 9-3 Conventional natural gas is more plentiful than oil, has a medium net energy yield and a fairly low production cost, and is a clean-burning fuel, but producing it has created environmental problems. 6. Distinguish between natural gas, liquefied petroleum gas, and liquefied natural gas. 7. List the advantages and disadvantages of using natural gas as an energy source. 9-4 What are the advantages and disadvantages of using coal? Coal is a solid fossil fuel that cheap and plentiful in much of the world. Coal is burned in power plants to provide about 42% of the world's electricity. However, burning coal releases large amounts of soot, carbon dioxide, and trace amounts of toxic mercury and radioactive materials. CONCEPT 9-4A Conventional coal is plentiful and has a high net energy yield at a low costs, but using it results in a very high environmental impact. CONCEPT 9-4B We can produce gaseous and liquid fuels from coal, but they have lower net energy yields and using them would result in higher environmental impacts than those of conventional coal. 8. Evaluate the usefulness of coal as an energy source. 9-5 What are the advantages and disadvantages of using nuclear energy? To evaluate nuclear energy, we must consider safety, economic feasibility, and environmental feasibility of the entire nuclear fuel cycle, from mining fuel to dealing with the waste. CONCEPT 9-5 When safely operated, nuclear power plants have a low environmental impact and a low accident risk, but the use of nuclear power has been limited by a low net energy yield, high costs, a public fear of accidents, long-lived radioactive wastes, and its role in spreading nuclear weapons technology. 9. What are the advantages of nuclear power? 10. What are the challenges associated with using nuclear power? Be sure to consider all parts of the nuclear fuel cycle. 11. What are important considerations in predicting the future of nuclear power? Key Terms commercial energy net energy yield petroleum crude oil peak production petrochemicals proven oil reserves oil sand tar sand oil shales natural gas liquefied petroleum gas (LPG) liquefied natural gas (LNG) coal synthetic natural gas (SNG) nuclear fission radioactive isotopes radioisotopes nuclear fuel cycle nuclear fusion Outline 9-1 What Is Net Energy and Why Is It Important? A. Solar energy produces several indirect forms of renewable energy: wind, hydropower, and biomass. B. Most commercial energy (92%) comes from nonrenewable sources, predominantly fossil fuels. C. Nonrenewable fossil fuels are widely used because they are abundant, cheap, and transportable. 9-2 What Are the Advantages and Disadvantages of Using Oil? A. Crude oil is extracted from underground deposits where it is dispersed in pores and cracks within rock formations. 1. After years of pumping, the pressure in a well drops, resulting in a decline in oil production – this is called peak production. 2. Refining is the process of separating petroleum into different components with different boiling points. 3. This process decreases the net energy yield of oil. B. Most of the world's remaining oil is not easily available 1. The oil industry is the world's largest business; control of oil reserves is the single greatest source of global economic and political power. 2. Proven oil reserves are identified deposits from which oil can be recovered. 3. The 12 countries of OPEC have about 72% of the world’s proven oil reserves. 4. The U.S. Produces about 8% of the world's crude oil, but uses 21% of global oil production. U.S. demand continues to increase, but our domestic supplies cannot be increased to meet this growing need. C. While conventional oil is abundant now, relatively cheap with a high net energy yield, it also has huge environmental costs, is priced artificially low, and contributes carbon dioxide to the atmosphere. D. Heavy oils in oil sand and oil shale can supplement conventional oil but carry a huge environmental cost to extract and refine. 1. Extracting oil from these sands impacts the land, air, water, wildlife, and climate. 2. The world has large deposits of oil shales that are locked in low grade rock, making it extremely energy-consuming to extract. Extraction would require large amounts of water and would release large amounts of carbon dioxide into the atmosphere. 9-3 What Are the Advantages and Disadvantages of Using Natural Gas? A. Conventional natural gas is a mixture of methane with smaller amounts of propane and butane and hydrogen sulfide; it is found above reservoirs of crude oil. B. Propane and butane gases are liquefied and removed from a natural gas field as liquefied petroleum gas (LPG). C. Natural gas is converted to liquefied natural gas (LNG) for transport in tanker ships. D. Unconventional natural gas, such as coal bed methane gas or methane hydrate, is too costly to extract. E. The U.S. Produced 20% of LNG and used about 22%. Demand in the U.S. is expected to double by 2050. 9-4 What Are the Advantages and Disadvantages of Using Coal? A. Coal is an abundant fossil fuel that is burned to generate about 45% of the world's electricity; 37% of the electricity in the US; 73% of the electricity in China. B. Coal damages the environment (land, air, water) and releases more carbon dioxide into the air than either oil or natural gas. C. Producing gaseous and liquid fuels from coal (synthetic natural gas; SNG) help it burn cleaner but it is expensive and adds 50 percent more carbon dioxide to the atmosphere than burning coal. Synfuels have a lower net energy yield than coal. 9-5 What Are the Advantages and Disadvantages of Using Nuclear Energy? A. Nuclear fission releases large amounts of energy when the nuclei of certain isotopes are split apart. 1. Multiple fissions form a chain reaction, which releases an enormous amount of energy. 2. Fission produces radioactive isotopes (radioisotopes), which can harm human cells by damaging DNA or causing tissue damage (burns, cancer). 3. Light-water reactors are used to produce nuclear energy. Control rods move in and out of the reactor core to regulate the rate of fission and thereby the amount of power produced. Water cools the fuel rods and reactor core, within a containment shell that prevents leaks of nuclear material. 4. The energy generated in the reactor is used to convert water to steam, which drives a turbine, thereby generating electricity. B. Despite large fuel supply, relatively low environmental risk, and low risk for accidents, use of nuclear power has not increased as once predicted. 1. No new nuclear power plants have been built in the U.S. since 1978. 2. High cost overruns, high operating costs, strict regulations, and public concerns about safety have all contributed to the lack of growth in nuclear power. C. Dealing with radioactive waste is a significant challenge. 1. Spent-fuel sites are often aboveground and not well-secured, making them vulnerable to sabotage or attack. 2. Radioactive waste must be stored safely for 10,000–240,000 years. Although most experts agree this should be done through deep burial, no country has built a disposal site. 3. The controversy around a waste burial site at Yucca Mountain in Nevada is a prime example; see Case Study: High-Level Radioactive Wastes in the United States. D. Can nuclear power reduce our oil dependence and reduce projected climate change? 1. Nuclear power currently produces about 8% of electricity in the US – not enough to reduce our use of oil. 2. While operating nuclear power plants does not produce carbon dioxide; enormous amounts of CO2 are produced at most of the steps along the nuclear fuel cycle, including manufacturing of cement to build the power plants themselves. E. Will nuclear fusion save us? 1. Nuclear fusion occurs when the nuclei of two isotopes of light elements are forced together at extremely high temperatures until they fuse to form a heavier nucleus – releasing lots of energy. 2. Many of the risks associated with fission are not present with fusion (no meltdown, no risk of radioactive material release/attack, etc. 3. More than 50 years of research has not generated a feasible approach. F. Experts disagree on the future of nuclear power. 1. Nuclear energy research receives significant amounts of government research and development money in the U.S. and around the world. 2. Proponents of nuclear power argue that those funds should continue supporting the development of safer and cheaper reactor designs for future use. 3. Opponents point out that nuclear power cannot compete in the power marketplace without these significant subsidies. Many feel that these funds would be better spent on renewable energy sources and promoting energy efficiency. Teaching Tips 1. High gas prices have made many people more aware of their dependence on their cars for transportation, and have sent many people looking for alternatives. Engage your students with the topics in this chapter (and preview the next one!) by discussing the impact of high gas prices, changes in their habits or those of friends/family, and how their awareness of this issue has changed as the price has increased. 2. Often, students are not aware of the electricity sources used to power their homes, the college, etc. See if your local power company has information about where their energy comes from as a way to introduce the topic. 3. Discussing fossil fuels presents an opportunity to discuss how short-term planning and interests compare to long-term thinking and interests. Discuss how we take fossil fuels for granted (supply, low cost, etc.). 4. Investigate the current US administration's policy on nuclear power plants. Is it promoted as part of an “environmentally friendly” energy policy? Term Paper and Discussion Topics Conceptual Topics 1. Oil and natural gas. Oil prices and economic development in the developing countries; enhanced oil-recovery techniques; shale oil extraction; petrochemicals; heavy oils from Athabascan tar sands; Alaska’s Prudhoe Bay gas deposits offshore drilling regulations in the United States. 2. Coal. U.S. low-sulfur coal reserves; geographic distribution of coal-burning power plants in the United States; fluidized-bed combustion; the U.S. Synthetic Fuels Corporation; China's use of coal. 3. Nuclear fission. Centralized energy planning in France; genetic damage to A-bomb survivors; Three Mile Island; Chernobyl; how nuclear fuel assemblies are made; radioactive tailings as a health hazard; geologic repositories for high-level radioactive wastes; commercial low-level nuclear waste dump sites; storing high-level liquid wastes; geographic distribution of nuclear power plants in the United States; keeping weapons-grade nuclear materials “out of the wrong hands”; nuclear reprocessing plants, Yucca Mountain nuclear waste storage site. New nuclear power plant construction in Georgia (2010). Attitudes & Values 1. What is the major energy source for heating your living space? 2. What is the major energy source for providing electricity to your living space? 3. How do you feel toward different energy sources? 4. Would you favor a $2 tax on every gallon of gasoline and heating oil to help reduce wasteful consumption, extend oil supplies, reduce air pollution, delay projected global warming, and stimulate improvements in energy efficiency and the use of less harmful energy sources? 5. Do you feel that the application process for nuclear power plants should be streamlined to limit citizen input? 6. Do you think emphasizing nuclear power and oil as the primary U.S. energy sources shows adequate concern for future generations? Action-Oriented Topics 1. As a class exercise, make a list of the geopolitical responsibilities and costs incurred by the United States in association with maintaining an uninterrupted supply of affordably priced oil from foreign sources. 2. A new power plant must be built in your community, but it remains to be decided whether it will be a fossil fuel or a nuclear plant. As a class exercise, set up a mock public hearing to present the arguments for both sides. Make specific role assignments so that prepared statements will accurately reflect varying points of view such as those of contractors, environmentalists, project engineers, state energy officials, and concerned citizens. Activities and Projects 1. Arrange a class excursion to a coal-burning power plant in your vicinity. Have a company spokesperson explain the electricity-generating process and the design and operating features of equipment and systems that control air pollution emissions and reduce thermal water pollution. 2. If there is a nuclear power plant operating in your vicinity, schedule a guided tour for your class. Invite a spokesperson from your local emergency disaster preparedness agency to present a guest lecture explaining the emergency evacuation plan for this facility. 3. Research the sources of electricity for your local power company (most of this information is available on their website). How does your local power supplier compare to the state and national averages for percentages of power that come from fossil fuels? From renewable resources? BBC News Videos The Brooks/Cole Environmental Science Video Library with Workbook, Featuring BBC Motion Gallery Video Clips, 2011. DVD ISBN: 978-0-538-73355-7 (Prepared by David Perault) Does Clean Coal Exist? Finding Alternatives to Oil Suggested Answers to Critical Thinking Questions 1. Answers on this one may vary but should address the idea that it may not be reasonable to focus solely on high net yield solutions. A realistic plan would be to diversify among different solutions that may be high or medium net yield. Low or negative net yield solutions will only work if given subsidies. A government needs to decide if it worth subsidizing low or negative net yield projects, or if it should focus on high and medium yield. In addition to net yield, governments should also consider how the solutions will affect the overall economy and address environmental concerns. 2. It is unlikely that we can continue to discover new, large oil reserves on a regular and continuous basis. There are a wide range of answers that can come up for future effects. These will include economic, environmental, societal, and lifestyle changes. 3. While it is true that the U.S. and European nations went through their industrial revolution at a time when they burned coal freely without regard to the environment, China is in a particularly unique situation due to its huge population (and resultant energy needs) as well as our knowledge and available technologies to decrease the environmental impact of such an industrial revolution. While it may be unrealistic to ask China not to pursue industrial and economic development, countries of the world must pressure China to use the cleanest methods possible. One thing that developed nations have learned: Once you get into “dirty” habits, it is very difficult to go back and implement cleaner technologies or approaches later. It is much better to start in the most sustainable way possible, and move forward from there. It may be up to the remainder of the world to supply these technologies at a discount or help China in developing their own clean approaches, to ensure that high standards are held up. 4. Agree or disagree with the following: a. Develop domestic oil supplies. For: reduce dependence on foreign oil, decrease cost of gas and other petrochemical products. Against: protect wild areas like ANWR and offshore areas from exploitation, they don't have enough oil to add to our long-term supply anyway, reduce likelihood of environmental damage; we need to decrease demand not increase supply. b. Heavy tax on gasoline and imported oil. For: reduce demand, encourage alternatives to gasoline (carpooling, public transit, electric/hybrid vehicles). Against: unfairly penalizes low-income families who pay higher percentage of income for gasoline; we have too many taxes as it is, will cripple the economy as people are very dependent on gasoline for daily life, increases costs of food and other goods. c. Increase dependence on coal. For: inexpensive, widely available fuel, existing infrastructure to convert to electricity, keeps electricity costs down. Against: high environmental cost to convert to electricity, dangerous and environmentally costly to mine. d. Increase dependence on nuclear power. For: relatively low environmental impact, high net energy yield, safe. Against: Difficult to safely store nuclear waste; technology could become available to those wanting to make weapons; if failure of safety procedures were to occur, results would be catastrophic. e. Phase out nuclear plants. For: cleaner technologies that do not have large amounts of hazardous waste are available; high cost of managing and operating the plants; eliminate risk of melt-down. Against: very high cost to decommission plants; where will replacement energy come from? 5. Transporting high-level nuclear waste through your area to a centralized storage site is not favorable. There is high risk for radioactive material to leak out in case of train derailment or accident, and high vulnerability to attack. No one wants such hazardous material transported through their neighborhoods, near their homes, food supplies, water reservoirs, playgrounds, parks, schools, campgrounds, etc. Any level of exposure in these areas would have a significant impact on the health and well-being of the population. Alternatives include local storage sites for waste instead of centralized storage sites. 6. If there was a policy to increase dependence on nonrenewable resources in the coming 50 years, those policies may include: increased oil production, increased use of nuclear power, continue subsidies for coal, oil, nuclear power production, minimally increased car fuel efficiency standards. 7. Answers will vary. Pay particular attention to these unanswered questions of interest as ideas for guest speakers, connections you can return to later in the course, and topics to include next time you teach this course. Chapter 10 Energy Efficiency and Renewable Energy Summary and Objectives 10-1 Why is energy efficiency an important energy source? Reducing energy waste is the quickest, cleanest, and usually the cheapest way to provide more energy, reduce pollution and environmental degradation, slow global warming, and increase economic and national security. CONCEPT 10-1 Energy efficiency improvements could save at least 33% of the energy the world uses and up to 43% of the energy used in the United States. 1. Explain why we can think of energy efficiency as an energy resource. 2. Define cogeneration and describe its potential for saving energy. 3. Describe changes that can be made in industry, transportation, buildings, lights, and appliances that would improve energy efficiency. 10-2 What are the advantages and disadvantages of using solar energy? On both an individual and industrial scale, solar energy can be used to generate needed thermal energy and electricity. With increased research and development and subsidies, solar cells could provide 25% of the world's electricity by 2050. CONCEPT 10-2 We can use passive and active solar heating systems to heat water and buildings, and we can use direct sunlight to produce high-temperature heat and electricity. 4. List the advantages and disadvantages of using direct solar energy to heat buildings and water and to produce electricity. 5. Briefly describe a photovoltaic cell. Describe its usefulness and limitations in converting sunlight to electricity. 10-3 What are the advantages and disadvantages of using hydropower? Hydropower is the world's leading renewable resource used to produce electricity, providing 20% of the world's electricity. CONCEPT 10-3 We can use water flowing over dams, tidal flows and ocean waves to generate electricity, but environmental concerns and limited availability of suitable sites may limit our use of these energy resources. 6. List the advantages and disadvantages of using water in the forms of hydropower, tidal power, and wave power to produce electricity. 10-4 What are the advantages and disadvantages of using wind power? Wind is an indirect form of solar energy that has the potential to supply a significant fraction of electricity used around the world. CONCEPT 10-4 When we include the environmental costs of energy resources in their market prices, wind power is the least expensive and least polluting way to produce electricity. 7. What are the arguments for and against installing wind farms? 8. What factors have contributed to the widespread use of wind power in Europe? 10-5 What are the advantages and disadvantages of using biomass as an energy source? Biomass is widely available as an energy source, yet the potential for unsustainable use of this resource is high. CONCEPT 10-5A Solid biomass is a renewable resource, but burning it faster than it is replenished produces a net gain in atmospheric greenhouse gases, and creating biomass plantations can degrade soil and biodiversity. CONCEPT 10-5B We can use liquid biofuels derived from biomass in place of gasoline and diesel fuels, but creating biofuel plantations can degrade soil and biodiversity, and increase food prices and greenhouse gas emissions. 9. List the advantages and disadvantages of using biomass to heat space and water, produce electricity, and propel vehicles. Consider burning wood, agricultural wastes, and urban wastes as well as conversion of biomass to biofuels. 10. What are the positive and negative impacts of Brazil's extensive use of sugar cane-derived ethanol? 10-6 What are the advantages and disadvantages of using geothermal energy? CONCEPT 10-6 Geothermal energy has the great potential for supplying many areas with heat and electricity, and it has a generally low environmental impact, but the sites where we can use it economically are limited. 11. Evaluate the usefulness of geothermal energy in providing space heating, high-temperature heat, and electricity. 10-7 What are the advantages and disadvantages of using hydrogen as an energy source? Scientists are working to solve the complex problems of hydrogen production and storage that are required to make a hydrogen economy a carbon-neutral reality. CONCEPT 10-7 Hydrogen is a clean energy source as long as it is not produced with the use of fossil fuels, but it has a negative net energy yield. 12. List the advantages and disadvantages of using hydrogen gas to heat space and water, produce electricity, and propel vehicles. 13. What energy sources are needed to produce hydrogen in truly sustainable manner? 14. Summarize constraints to a solar-hydrogen revolution. 10-8 How can we make the transition to a more sustainable energy future? Decisions about energy resources are influenced by companies, government, economic pressure, and political pressure from citizens. Experience shows that it usually takes 50 years and huge investments to phase in new energy alternatives. CONCEPT 10-8 We can make the transition to a more sustainable energy future by greatly improving energy efficiency, using a mix of renewable energy resources, and including environmental costs of energy resources in their market prices. 15. List the eight key questions that must be asked about each energy alternative to evaluate energy resources. 16. Analyze the interactions of economic policy and energy resources. In particular, consider the results of using free-market competition, keeping energy prices low, and keeping energy prices high. Key Terms cogeneration combined heat and power (CHP) green architecture passive solar heating system active solar heating system photovoltaic (PV) cells solar cells biomass geothermal energy Outline 10-1 Why Is Energy Efficiency an Important Energy Resource? A. The best way to cut energy waste is to improve energy efficiency. Forty-three percent of U.S. energy is wasted unnecessarily, mostly due to inefficient devices. B. The most energy-wasting devices are: incandescent light bulbs, internal combustion engines, nuclear power plants, and coal-burning power plants. C. Energy can be saved in industrial settings by using cogeneration, replacing electric motors, recycling materials, and switching to fluorescent or LED lighting. D. Energy can be saved in transportation by improving fuel efficiency in vehicles. 1. Gasoline is artificially cheap in the United States because the true environmental cost is not represented in the price consumers pay; government subsidies and tax breaks to oil companies also keep prices low. 2. Many people in the U.S. drive large, inefficient vehicles. There are not enough subsidies to encourage purchase of more fuel efficient vehicles. E. There is growing interest in energy efficient vehicles. 1. Gasoline-electric and plug-in hybrid electric vehicles are becoming more widely available. 2. Fuel cell vehicles are still in development, having the potential for twice the efficiency of internal combustion engines and requiring little maintenance. F. To save energy in buildings, we can get heat from the sun, super insulate the buildings, and initiate plant-covered Eco roofs – approaches that are part of green architecture. G. In existing buildings, we need to insulate and plug leaks, use energy efficient windows, heat our houses and water more efficiently, and use energy-efficient appliances and lighting. H. Low-priced fossil fuels and lack of government tax breaks for saving energy promote energy waste. 10-2 What Are the Advantages and Disadvantages of Using Solar Energy? A. By orienting buildings toward the sun (passive solar heating) and by pumping a liquid through rooftop collectors (active solar heating), we can use renewable solar energy. 1. Passive solar heating systems absorb and store heat from the sun directly within a structure. 2. Active solar heating systems absorb energy from the sun in a fluid (air, water, or antifreeze solution), which is pumped through special collectors on the roof or on racks that face the sun. 3. Solar thermal systems can be used in desert areas to generate heat that can be converted directly into electricity. 4. Solar cells (or photovoltaic cells) can be used to produce electricity for homes around the world. Until recently, the high cost of solar cells prohibited widespread use. 10-3 What Are the Advantages and Disadvantages of Using Hydropower? A. Hydropower is the world's leading renewable energy source used to produce electricity. B. Renewable hydropower takes water flowing in rivers and streams and traps it in reservoirs to be released to spin turbines, thereby producing electricity. C. Micro hydropower generators, small generators placed in a stream without altering its course, provide electricity at low cost with low environmental impact. D. Ocean tides and waves may also be useful in the future for hydropower, as technologies develop. 10-4 What Are the Advantages and Disadvantages of Using Wind Power? A. Wind power is the world’s most rapidly growing form of indirect solar energy. The drawback is that locations for truly effective wind turbines are limited; may are offshore. B. If the environmental costs of various energy resources are considered, wind energy is the cheapest and least polluting way to generate electricity. C. The greatest potential for wind power lies in sparsely generated areas, so transmission infrastructure will have to be improved to get the energy to areas that are more populated. D. Backup systems are needed, as wind is variable. 10-5 What Are the Advantages and Disadvantages of Using Biomass as an Energy Source? A. Biomass is primarily used for heating and cooking, but also for industrial processes. B. Biomass is often harvested faster than it is replenished, eliminating many of the environmental advantages of using this energy source. C. Plans and plant wastes can be converted to liquid biofuels (biodiesel, ethanol). This can be done sustainably at many places on the globe, and the infrastructure exists to store and distribute biofuels. See Case Study: Is Ethanol a Promising Fuel? D. Biofuels have significant advantages and serious drawbacks. 1. Advantages include wide growing regions, which would create local sources of fuel; they are available now with existing infrastructure, and when used sustainably, do not increase the net CO2 in the atmosphere. 2. Ethanol produced from sugarcane in Brazil is contributing to a loss of biodiversity. Ethanol produced from corn in the U.S. is contributing to rising prices of corn around the world. 10-6 What Are the Advantages and Disadvantages of Using Geothermal Energy? A. Geothermal heat pumps use a pipe and duct system to extract heat stored in underground rocks and fluids. The earth is used as a heat source in winter and a heat sink in summer. B. Hydrothermal reservoirs are being used to heat homes and buildings and even grow vegetables in greenhouses. The US is the world's largest producer of electricity from hydrothermal reservoirs. 10-7 What Are the Advantages and Disadvantages of Using Hydrogen as a Fuel Source? A. Using hydrogen gas as a fuel could reduce or even eliminate many of the pollution problems and CO2 emission problems we face today (provided the hydrogen gas is not produced using fossil fuels). B. However, it takes energy to release H2 from its source in organic compounds, it requires expensive fuel cell technology to fully utilize, and the process could be heavily dependent on fossil fuels for extracting the hydrogen. Ultimately, this means hydrogen's future as a fuel source is complex. 10-8 How Can We Make the Transition to a More Sustainable Energy Future? A. Energy-producing systems will shift from large, centralized micropower systems (such as coal-burning/nuclear power plants) to smaller, decentralized micropower systems (such as wind turbines, fuel cells, solar panels, and small natural gas turbines). B. A combination of improved energy efficiency and fuels such as natural gas and biofuels will provide a transition to the use of various small-scale, decentralized, locally available renewable energy resources. C. Fossil fuels will continue to be used, primarily due to their abundant supplies and artificially low prices. The harmful effects of fossil fuels on the environment need to be reduced, especially those of air pollution and greenhouse gases. D. Governments must combine subsidies, tax breaks, and taxes to promote/dampen various energy choices. 1. By keeping selected energy resource costs artificially low, use and even waste is encouraged, and the development or use of alternatives is discouraged. 2. By keeping energy prices artificially high, use of a particular resource is discouraged. 3. By promoting education, governments can encourage people to make informed choices about their energy use. Teaching Tips 1. Students will have varying levels of familiarity with renewable energy resources. An introductory discussion of what they know about renewable resources will help set the stage. What have they heard are the reasons for and against the widespread adoption of many of these resources? Be sure to highlight any misconceptions or political spin that is not environmentally correct. 2. A discussion of what it truly takes to change our habits and attitudes toward renewable and sustainable resources can be very engaging. Understanding how entrenched we are as people (especially Americans) in our “way of life” and how resistant we often are to change is enlightening when related to making the changes needed to live a more sustainable lifestyle. What is the role of peer pressure here? Term Paper and Discussion Topics Conceptual Topics 1. Improving energy efficiency. Energy-efficient office buildings; earth-sheltered houses; retrofitting energy-wasting houses; superinsulation; earth tubes; evaporative coolers; energy-efficient appliances; compact fluorescent light bulbs; “smart” and super insulated windows; roof-attachable solar cell rolls; the Albers Technologies air conditioner. 2. Solar technologies. The solar power tower; solar power satellites; photovoltaics; active solar systems; passive solar heating; microprocessors to control house temperatures. 3. Biomass. Modern wood stoves; bagasse as a biomass fuel; biogas digesters in the developing countries; gasohol; methanol. 4. Wind. Wind farming in California; wind turbine designs. 5. Water power. Large-scale hydropower projects in the developing countries; rehabilitating small-scale hydroelectric plants in New England; wave power devices—a comparison of various approaches; ocean thermal energy conversion; solar ponds; the Bay of Fundy tidal power project. 6. Hydrogen gas: a versatile fuel of the future. Attitudes & Values 1. How do you feel toward different energy sources? 2. What would be the best alternative energy source in your area? 3. Do you feel a responsibility to use energy wisely? What steps are you willing to take to reduce your energy consumption? 4. How do you feel toward decentralization of the power grid? 5. Do you favor policies that encourage energy conservation and more development of renewable and perpetual energy sources? 6. Would you support laws requiring that all new homes and buildings meet high energy efficiency standards for insulation, air infiltration, and heating and cooling systems? Would you favor such a law for existing homes and buildings? 7. Choose: free-flowing streams or a network of small-scale hydropower facilities? 8. Should millions of homeowners erect small wind turbines for electrical production? 9. Should building codes be required to include passive solar concepts? 10. Do you feel that the application process for nuclear power plants should be streamlined to limit citizen input? Action-Oriented Topics 1. Individual. Household energy savings. 2. Industry. The horizontal integration of large energy companies. 3. National. Government taxing and subsidizing policies and energy conservation; the National Audubon Society intermediate national energy strategy; an evaluation of the current administration’s energy plan. The Atomic Energy Commission (1946–1975); the Nuclear Regulatory Commission; the Energy Research and Development Administration (ERDA); the Nuclear Safety Analysis Center; the Institute of Nuclear Power Operations; the Price-Anderson Act. Activities and Projects 1. Ask an architect or contractor with experience in decentralized use of perpetual and renewable resources to visit the class and discuss the practical aspects of designing, financing, and installing small-scale solar, wind, and biogas systems for individual residences, farms, businesses, or factories. 2. Find out if representatives from your local electrical utility offer customers energy audits of their homes. If so, ask them to come to your class and describe what they look for in homes and what seem to be the most frequent ways that customers can increase their energy efficiency. 3. Have your students find out if your institution’s electrical utility has a conservation program. Does it have policies that encourage customers to purchase energy-efficient appliances and use energy-efficient light bulbs? 4. Organize a class field trip featuring guided tours of homes and/or other buildings that have solar heating systems. If possible, include examples of both passive and active systems and an earth-sheltered house. 5. As a class project, identify the major energy-related economic, political, environmental, and social problems in your community and state. What specific actions are being taken to alleviate these problems? Are these piecemeal efforts, or are they components of comprehensive and internally consistent energy plans? 6. Bring to class recent issues of periodicals devoted exclusively to renewable energy industry reporting. As a class exercise, scan the contents of these periodicals to see what research and development is on the cutting edge of progress. 7. Have your students audit energy use and waste on your campus and in activities (such as commuting) associated with the operation of your campus. Are opportunities to conserve significant amounts of energy going unrecognized or ignored? 8. As a class project, conduct a survey of students at your school to determine what beliefs and attitudes they have regarding sustainable-earth energy alternatives that entail a loss of convenience or additional expenditures of time and money on the part of energy users. Are young people today willing to significantly alter their lifestyles to use and waste less energy? 9. As a class project, develop a simple questionnaire or test that can be used to measure a person’s knowledge about the efficiency of various energy conversion devices, appliances, and systems in common use. What is the “energy IQ” of the average student on your campus? To obtain a crude measure, administer the test to a random sample of students and analyze the results. 10. Have your students examine recent issues of weekly news magazines, local newspapers, and nationally recognized newspapers. How much space is devoted to energy-related reporting and analysis? What is the relative degree of emphasis placed on developing alternative energy sources and systems? Curbing energy waste? Lifestyle adjustments that reduce energy needs? How are energy-related topics and issues handled in the Wall Street Journal and Fortune? How does corporate advertising address energy topics and issues? In these and other ways, try to determine how thoroughly and accurately the public is being informed about matters of critical importance to the nation’s energy future. 11. As a class exercise, (a) obtain cost estimates for the construction of a single large-scale synfuels plant, and (b) calculate how many soft-path energy facilities or systems of various types (such as solar water heaters, biogas digesters, and photovoltaic devices) could be installed with an equivalent amount of money. BBC News Videos The Brooks/Cole Environmental Science Video Library with Workbook, Featuring BBC Motion Gallery Video Clips, 2011. DVD ISBN: 978-0-538-73355-7 (Prepared by David Perault) End for Selling Traditional Bulbs Plastic Bag Charge Debated Finding Alternatives to Oil Suggested Answers for Critical Thinking Questions 1. Many ways to unnecessarily waste energy during the day: leaving lights on, leaving computer on when not in use, driving short distances that can be walked instead, keeping air conditioning set very low (or heat set very high), not recycling materials, not reusing materials when possible, purchasing foods or products from far away instead of those produced locally, and others. Those activities that waste fossil fuels are not relying on solar energy; those that use products produced far away do not rely on locally available resources and biodiversity; throwing away items that could otherwise be recycled or reused does not participate in nutrient recycling. 2. In describing the design for a house that is energy efficient, students may discuss location and materials that support passive solar heating, solar heating for water, energy star appliances for stove, refrigeration, washer, dryer (or have clothesline, with dryer for rainy days only!), CFLs or LEDs for lighting, and other such energy-efficient approaches to each of the questions given. 3. “Yes, efficient vehicle purchasers should receive subsidy” arguments may include: promote purchases of these vehicles, need to offset high costs of technology, a worthwhile investment to reduce overall energy demand, etc. “No, should not receive subsidy”: government cannot afford it in tough financial times, unfair to those who cannot afford such expensive vehicles, government should not be promoting car purchases of any sort—only public transit, some large families need big cars—unfair to penalize them because they cannot fit family into small vehicle. 4. Explain why you agree or disagree: a. For free markets: need to cut government budgets; market will show what is viable from consumer's perspective. Against free markets: new technologies have no chance of widespread adoption without help to bring down costs or promote use. Subsidies are a powerful way to help people change their habits (money talks). b. For eliminating government subsidies for nonrenewable sources; replace with subsidies for renewable resources and energy efficiency: costs for nonrenewable sources would significantly increase, driving down consumption; people will change their habits to use less of those resources. Subsidies for renewable resources will encourage people to use those resources, especially if they cannot afford to make initial, large investment often required to make a significant change in their habits or their lifestyles. Developing new resources will help bring down cost of that technology eventually, making it more accessible for everyone. Against: We are too dependent on fossil fuels in our economy— significant economic hardship if costs rise significantly and quickly for fossil fuels and electricity generation. These are things we just can't live without. c. For leaving development of renewable resources to private sector without government support; fossil fuels continue to receive subsidies: the private sector can often get things done more quickly, more cheaply, and more effectively than the government. Against leaving development of renewable resources to private sector: government support is key, both monetarily and influencing public opinion about renewable resources. 5. In allocating resources for Dept of Energy, students should discuss their priorities and why those things are important. In keeping with principles of sustainability, students should promote energy efficiency (always easier not to pollute or waste initially than to pollute/waste and clean up afterwards) and renewable resource development. Availability or feasibility of some resources over others (e.g., wind power, hydroelectric power, etc.) could influence their choices. Infrastructure availability and upfront costs are also key considerations. 6. Energy policy features should include concepts consistent with the principles of sustainability: reliance on solar, decreased use of fossil fuels, development of infrastructure and mechanisms to better utilize renewable resources, maintaining biodiversity as renewable resources are developed. 7. Answers will vary. Use these as a way to link back to this chapter in later classes or as ideas for new material to incorporate in future courses. Chapter 11 Environmental Hazards and Human Health Summary and Objectives 11-1. What major health hazards do we face? We face a variety of health hazards; it is important to go through the processes of risk assessment and risk management to determine actions to be taken to minimize risks to our health. CONCEPT 11-1 We face health hazards from biological, chemical, physical, and cultural factors and from the lifestyle choices we make. 1. Define risk, probability, and risk assessment. List five general types of common hazards and give two examples of each. 11-2. What types of biological hazards do we face? Infectious diseases are caused by pathogens (bacteria, viruses) that infect our bodies. How easily the pathogen is spread, how resistant it is to antibiotics or other treatment, availability of that treatment, and rate of infection all contribute to the prevalence of a particular infectious disease in a given region. The WHO estimates that only 10% of global medical R&D goes to preventing infectious diseases in less developed countries. CONCEPT 11-2 The most serious biological hazards we face are infectious diseases, primarily flu, AIDS, tuberculosis, diarrheal diseases, and malaria. 2. Transmissible diseases can be spread from one person to another. List two factors that contribute to the spread of infectious diseases. 3. Tuberculosis is a significant infectious disease problem. List several reasons that fighting TB infections is especially difficult. 4. The global HIV/AIDS pandemic has caused significant death around the world, especially in Sub-Saharan Africa. List three impacts of the AIDS epidemic on communities in Sub-Saharan Africa. 5. List three approaches to preventing malaria. 11-3. What types of chemical hazards do we face? Typically, 10-40 years may elapse between initial exposure to a carcinogen and the appearance of detectable symptoms. CONCEPT 11-3 There is growing concern about chemicals in the environment that can cause cancers and birth defects, and disrupt the human immune, nervous, and endocrine systems. 6. Define mutagen, teratogen, and carcinogen. Summarize current research implying chemical effects on the immune, nervous, and endocrine systems. 11-4. How can we evaluate chemical hazards? There are many variables involved in estimating the effects of human exposure to chemicals. Most commercially used chemicals have not been screened for toxicity. Because we know so little and it is nearly impossible to thoroughly test all chemicals in use, many health officials recommend pollution prevention as the best measure. CONCEPT 11-4A Scientists use live laboratory animals, case reports of poisonings, and epidemiological studies to estimate the toxicity of chemicals, but these methods have limitations. CONCEPT 11-4B Many health scientists call for much greater emphasis on pollution prevention to reduce our exposure to potentially harmful chemicals. 7. Chemical hazards, for example, are defined by their toxicity, the person’s acute and chronic reactions to it, and its pervasiveness in the environment. 8. Toxicity estimates are based on case reports and epidemiological studies; animal testing can also be used to estimate toxicity. 9. Define dose and response. Distinguish among acute, chronic, and sub chronic exposures. Distinguish among acute and chronic effects. Summarize three methods used to enhance our understanding of toxicity of chemicals. 10. Define a dose-response curve. Distinguish between a linear dose-response model and a threshold dose-response model. Describe the difficulty in deciding which model applies best when low doses are involved. Assess the limits of toxicological research. 11-5. How do we perceive risks and how can we avoid the worst of them? The greatest risks for premature death are poverty, gender, and lifestyle choices. Comparative risk analysis is critical for understanding relative risk from ecological and health problems. CONCEPT 11-5 We can reduce the major risks we face by becoming informed, thinking critically about risks, and making careful choices. 11. Summarize key questions to be answered in risk-benefit analysis, risk assessment, and risk management. What are the useful applications and limits of these analyses? 12. List five factors that can cause people to perceive that a technology or product has a greater risk than the risk estimated by experts. Key Terms risk risk assessment risk management pathogens infectious disease transmissible disease nontransmissible disease emergent diseases toxic chemicals carcinogens mutagens teratogens toxicology toxicity dose response dose-response curve risk analysis Outline 11-1 What Major Health Hazards Do We Face? People face health hazards from biological, chemical, physical, and cultural factors and from the lifestyle choices they make. A. A risk is a measure of your likelihood of suffering harm from a hazard. 1. Such a hazard may cause injury, disease, economic loss, or environmental damage. 2. Risk is projected as a probability, an estimate of an event actually happening. B. There are several types of hazards. 1. Biological hazards come from pathogens. 2. Chemical hazards are harmful chemicals in the air, water, soil, and food. 3. Physical hazards include fire, earthquakes, floods, etc. 4. Cultural hazards include unsafe working conditions, criminal assault, and poverty. 5. Lifestyle choices include smoking, poor diet, drugs, and unsafe sex. 11-2 What Types of Biological Hazards Do We Face? A. Some diseases can spread from one person to another. 1. Nontransmissible diseases are not caused by living organisms and do not spread from one person to another. a. Examples are cancer, diabetes, asthma, malnutrition, and cardiovascular disorders. 2. Infectious diseases are caused by pathogens. Transmissible disease (contagious disease) is an infection that can be transmitted to another person. a. Examples are flu, AIDS, tuberculosis, and measles. b. Many pathways for infectious diseases, including air, water, food, bodily fluids, etc. c. Immunity to antibiotics is a growing concern for treating diseases. See Science Focus: Genetic Resistance to Antibiotics is Increasing. 3. Tuberculosis is a highly infectious and easily transmissible disease. See Case Study: The Growing Global Threat from Tuberculosis. a. There are too few TB screening and control programs. b. Most TB strains have developed genetic resistance to antibiotics. c. Increasing urbanization and population growth increase transmittal of the disease. d. AIDS weakens immune systems and makes AIDS sufferers prone to developing TB. 4. Viral disease is a great threat to people worldwide. a. Influenza (flu), HIV, and hepatitis B (HBV) are the most dangerous and most widespread viruses worldwide. b. Health officials are worried about the spread of emerging diseases such as SARS and West Nile viruses. 5. AIDS is a global epidemic; it leaves the body vulnerable to infections by other pathogens. See Case Study: The Global HIV/AIDS Epidemic. a. AIDS has reduced the life expectancy of the 750million people living in sub-Saharan Africa from 62 to 47 years, on average and to 40 in the seven countries most severely affected by AIDS. b. Premature deaths of parents, teachers, healthcare workers, and many others leave a significant gap in the country's infrastructure as well as in families themselves. 6. Malaria is one of the most virulent viral diseases. It is caused by protozoan parasites in the genus Plasmodium. See Case Study: Malaria – The Spread of a Deadly Parasite. a. Plasmodium circulates from mosquito to human and back to mosquito. b. A vaccine for malaria is difficult to develop, so prevention programs provide more success. 1) Prevention methods include increasing water flow in irrigation systems. 2) Prevention includes fixing leaking water pipes, sleeping under mosquito nets, cultivating fish that feed on mosquito larvae, clearing vegetation away from houses, planting trees that soak up water in marsh areas, and using zinc and vitamin A supplements to boost resistance in children. 7. Straightforward measures can help reduce incidence of infectious diseases, including immunization, oral rehydration therapy, and access to safe drinking water. 11-3 What Types of Chemical Hazards Do We Face? Toxic chemicals may affect our immune, nervous, and endocrine systems. A. Toxic chemicals are poisonous substances that cause temporary or permanent harm or death to animals and humans. There is often a long lag between exposure and appearance of symptoms. 1. Carcinogens cause or promote cancer. 2. Mutagens cause mutations in DNA molecules. 3. Teratogens cause birth defects while the human embryo is developing during pregnancy. B. Chemicals disrupt the immune, nervous, and endocrine systems with long-term exposure to low doses of chemicals. 1. Chemicals can impact the immune system by decreasing its functionality, leaving the body susceptible to infection. 2. Neurotoxins are types of poisons that can impact the brain and nervous system, causing behavioral changes, retardation, paralysis, or even death. 3. Hormonally active agents (HAAs) can mimic the body's hormones that control sexual reproduction, growth, development, or even behavior. 11-4 How Can We Evaluate Chemical Hazards? A. The harm that chemical exposure produces depends on several factors, including: 1. The dose and frequency of exposure 2. The age and genetic makeup of person exposed 3. The efficiency of the body’s detoxification systems (liver, lungs, kidneys) B. The type and amount of health damage resulting from exposure to a chemical is called the response. 1. An acute effect is immediate or rapid response to the chemical. 2. A chronic effect is permanent or long-lasting impact from the chemical. C. Laboratory research is widely used to estimate toxicity. 1. Animal testing takes two to five years, costs millions of dollars, and involves large numbers of animals, yet it may be the best way to study the intricate biochemical interactions taking place in a living organism. 2. Alternatives to animal testing include computer modeling, tissue culture, and measuring changes in individual cells instead of the entire organism. 3. Dose response curves are used to examine the effects of various doses of the chemical on experimental animals. 4. Three main challenges with studying toxicity are estimating low-dose effects, extrapolating results from rats/mice to humans, and understanding the effects of multiple chemicals in combination. D. Studies after chemical exposure can also help scientists understand toxicity. 1. Case reports from physicians and epidemiological studies can be useful in identifying associations between exposure and health effects. 2. Limitations to these methods include small sample size, lack of conclusive links, and inability to evaluate new hazards this way. E. Toxicology is complex; natural isn't necessarily safe, synthetic isn't necessarily harmful. Scientists do not fully understand the impact of low dose chemicals over the long term. 1. Most chemicals have not been adequately tested for toxicity; most chemicals are not regulated. 2. Using a precautionary principle of avoiding exposure is a smart approach. 11-5 How Do We Perceive Risks and How Can We Avoid the Worst of Them? A. Risk analysis involves identifying hazards and evaluating their associated risks. B. People’s greatest risks around the world are the effects of poverty on human health and personal lifestyle choices. 1. Poverty produces malnutrition, increased susceptibility to normally nonfatal infectious diseases, and lack of a safe water supply. 2. Lifestyle choices including smoking, losing excess weight, regular exercise, and limiting alcohol intake. C. The more complex a technological system is, and the more people needed to design and run it, the more difficult estimating risks becomes. 1. The overall reliability of any technological system is the product of technological reliability and human reliability, both of which are fallible. 2. People often fear low-risk events while ignoring the higher-risk activities present in their daily lives. See Case Study: Death from Smoking. 3. Several factors distort our sense of risk: a. Fear of the unknown. b. Degree of control. c. Whether the risk is catastrophic. d. Optimism bias. e. Fun and/or instant gratification. f. Unfair distribution of risks. D. Evaluating risks 1. Compare risks. 2. Determine how much risk you are willing to accept. 3. Evaluate news reports critically. 4. Focus on avoiding the most serious risks. 5. Focus on what you can control. 6. Use principles of sustainability to help reduce risks. Teaching Tips 1. Capture students' interest in organic versus regularly farmed foods with a taste test. Can students taste the difference in organic and regularly farmed foods (chocolates, fruits, and vegetables are the most fun to try) in a blind taste test? Have students make predictions (e.g., taste, appearance, size, smell, etc) prior to tasting, take tasting notes, and then evaluate their tasting experience. In addition to aesthetics, compare availability, cost, agricultural impact, and other information. Explore assumptions students have about “organic” and “non-organic” foods in terms of chemicals, freshness, shelf-life, taste, friendliness to environment, etc. 2. Every week it seems there are more things identified that will either kill us or save us from an untimely death. Help students identify overly broad claims in those brief news articles that are not backed up scientifically. Examine the scientific studies in the primary literature and compare to how that is translated into mainstream media. Did the study use research animals or was it an epidemiological study in humans? What were the doses involved? How does that translate into regular human exposure to that chemical? What is the actual risk or benefit? 3. Connect the ideas of risk assessment with the critical thinking qualities discussed in the Introduction to the book. Many of the same concepts for detecting bad science are applicable in understanding risk. One creative way to start this conversation is by having students list as many urban legends as they can relate to risk of death, toxic chemicals, etc. Research the truth of such stories as a class on websites such as Snopes (http://www.snopes.com). Term Paper and Discussion Topics Conceptual Topics 1. Environmental risks. Brown lung disease and the textile industry; black lung disease and the coal mining industry; asbestos as a carcinogen. 2. Lifestyle risks. Health effects from secondary smoke; the rise in women's lung cancer rate effects of smoking and/or drinking habits later in life. 3. Transmissible disease risks. History of infectious disease control; vaccines and immunology; how smallpox was eradicated; waterborne diseases of the developing countries; the history of malaria; schistosomiasis; cholera; tuberculosis; AIDS. 4. When do smokers’ rights infringe on nonsmokers’ rights? What are local laws about where smoking is permitted? Find examples of very liberal and very restrictive laws. Describe the communities that adopted those laws. 5. Is there equity in exposure to hazardous chemicals? 6. Is carrying umbrellas the best approach to lowering exposure to ultraviolet rays made more intense by the increasing ozone hole? 7. Should utility regulators assume a linear dose-response curve in evaluating levels of exposure of the public to different hazardous chemicals? 8. Can we expect a worldwide epidemiological transition? 9. What are the pros and cons of risk-benefit analysis? Attitudes & Values 1. What kinds of risks do you take every day? 2. What kinds of risks from the natural environment occur in your area? 3. What kinds of risks are you exposed to each day over which you have no control? 4. Do you feel that societal risks should be distributed equally among all citizens? 5. Should people who choose unhealthy lifestyles be covered by national health insurance? Action-Oriented Topics 1. Individual lifestyle changes that cut risks. Quitting smoking; changing to a low-risk diet; steps to prevent breast cancer; preventive medicine. 2. Groups spreading the word about risks. The American Cancer Society; the American Lung Association; the American Heart Association, Mothers Against Drunk Driving, Students Against Drunk Driving. 3. National. The National Centers for Disease Control; Occupational Safety and Health Administration (OSHA); U.S. efforts to export tobacco products; the tobacco lobby; the Food and Drug Administration; new ingredient labels for food. 4. International. Sweden’s anti-smoking campaign. Activities, Projects, Guest Speakers 1. Have your students obtain mortality and morbidity data for people living in poor and affluent sections of your community to determine the frequency and types of illness. Compare results with national statistics and attempt to explain any significant local differences. GIS (geographic information system) is a powerful way to look at this data in conjunction with lmaps and other socioeconomic data. 2. What occupational health hazards are prevalent in your community? What is being done to protect workers from these on-the-job hazards? Have some students investigate this and report the results. 3. Have local public health officials discuss with your class the types and frequency of diseases in the local area and describe efforts for disease control. 4. Invite a spokesperson for the American Cancer Society (or other appropriate organization) to address your class on the subject of nonsmokers’ rights. What specific things can a person do to minimize his or her passive exposure to cigarette smoke? What are the limits of smokers’ rights to pollute air that nonsmokers cannot avoid breathing? Review the changes in attitudes and behaviors that people in the United States have shown toward smoking over the last 10 years. 5. Ask a nutritionist to explain to your students the problems with the typical U.S. diet and how to facilitate changes recommended by the National Academy of Sciences and the American Heart Association. 6. Assign several students to visit a store that specializes in organically grown and “natural” foods. Have them describe the advertising claims made on behalf of natural foods. Do a blind taste-test, comparing flavor and appearance. After tasting, discuss shopping choices when cost is factored in. BBC News Videos The Brooks/Cole Environmental Science Video Library with Workbook, Featuring BBC Motion Gallery Video Clips, 2011. DVD ISBN: 978-0-538-73355-7 (Prepared by David Perault) Who Pays the Price for Technology? What is the Environmental Cost for Your Food? Jean Suppliers Pollution End for Selling Traditional Bulbs China's Deadly Pollution Plastic Bag Charge Debated Suggested Answers to Critical Thinking Questions 1. Answers will vary. Topics of discussion may include some of the following: ○ Becoming informed: seek information from reliable, unbiased sources; be wary of biased information (on either side of issue). Seek validation of opinions from additional, unrelated sources. Look for facts behind emotional arguments or appeals. ○ Thinking critically: properly evaluate my risks; do not let news/media hype about a particular catastrophic event (or more mundane things like robbery, shootings, etc.) translate into how I interpret my own individual risk. Look past emotional arguments to find facts, do not be misled by so-called statistics; seek out full information about the arguments presented from unbiased sources. ○ Making careful choices: carefully evaluate areas where I do have control over a particular risk, make deliberate decisions to reduce risk in those areas (smoking, alcohol use, foods I eat, etc.). Be especially aware of optimism bias, and make changes in my own actions (e.g., drive more carefully). 2. The spread of infectious diseases such as HIV can impact the age structure of a population. As more people die from AIDS, an entire generation is being wiped out—leaving older people and the young to fill the gaps in society. Those who are dying tend to be in their most productive years of contributing to their communities (doctors, entrepreneurs, etc.). As a gap emerges in this age group, the young must take up the slack of raising families who are now without parents, and taking care of the elders, all without the infrastructure that the middle generation gave to the society and to their family. 3. Answers will vary, but may include some of the following ideas. a. TB: increase awareness and funding for research worldwide, increase screening programs, develop monitoring systems that will help reduce transmission due to worldwide travel, increase availability of drugs to treat disease, develop drugs that are effective in a shorter time frame. b. Malaria: increase distribution of bed nets, increase funding for research into vaccines, research pesticide-based or pesticide-free methods of insect control, increase education about how malaria is spread, and implement methods to reduce mosquito reproduction (interrupt life cycle), increase use of oral rehydration therapy, and boost natural parasite resistance (vitamin A, etc.) 4. Evaluate statements on chemical exposure. Answers will vary, but may address some of the following issues: a. Any chemical at a large dose can cause some harm: yes, but we are more concerned about chemicals at small doses that can also cause harm. Too much of anything is usually not a good thing. Not a good evaluation of the situation—focus is on wrong aspect of health impact. Prevention is something we can do here and now. b. Develop immunity: genetic adaptation will take generations, and the rest of us will die out in the meantime. Given the wide range and huge number of chemicals, the idea that we would somehow develop immunity to each of them and all of them in infinite combination is completely impossible (and incalculable!) Prevention is something we can do here and now. c. Genetic engineering: while we may be able to create bacteria, yeast, or worms that are resistant to chemical toxicity, transferring that to humans is nearly impossible. Genetic engineering of humans is not feasible yet—even if it were there are huge ethical considerations. Not a feasible approach. Prevention is something we can do here and now that does not take untold feats of molecular biology and leaps of ethics. 5. Major risks you face, voluntary or involuntary? Important things to do to reduce those risks. Which do you plan to do? Answers will vary, but may touch on some of the following: a. Lifestyle: voluntary risks such as driving (even more if you drive dangerously), drinking alcohol, drug abuse, smoking, hobbies with some risk of injury (surfing, mountain biking, rock climbing, soccer, basketball, volleyball, etc.). b. Where you live: involuntary risks such as air pollution, water pollution, power plants or other industry nearby, violence, risk of wildfire (consider voluntary component of where we live), or other natural disasters. c. What you do for a living: possibly a combination of voluntary and involuntary occupational hazards. 6. Supporting the legislation to implement pollution prevention in the precautionary principle: we know so little about so many chemicals, it is important that we minimize our exposure to potentially dangerous chemicals; we may not see ill effects for years after exposure, when it will be too late to go back. Against the legislation: too many regulations already, we do not know enough information about actual risks to evaluate risk correctly; threshold levels are set so artificially low already; regulations would inhibit development of new materials and chemicals to benefit society; just because we can create a test to detect minute levels does not mean they are dangerous at that level. 7. Answers will vary. Instructor Manual for Sustaining the Earth G. Tyler Miller, Scott E. Spoolman 9781285769493
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