1. © 2011 Pearson Education, Inc. Lecture Outlines Chapter 19 Environment: The Science behind the Stories 4th Edition Withgott/Brennan

2. © 2011 Pearson Education, Inc. Fossil fuels: our dominant source of energy Fossil fuels = highly combustible substances from the remains of organisms from past geologic ages, high energy content Electricity = a secondary form of energy that is easy to transfer and apply to a variety of uses Oil, coal, and natural gas have replaced biomass as our dominant sources of energy

3. © 2011 Pearson Education, Inc. Resources are renewable or nonrenewable Renewable energy = supplies will not be depleted by our use -Sunlight, geothermal energy, and tidal energy Nonrenewable energy = we will use up Earth’s accessible store in decades to centuries -Oil, coal, natural gas, nuclear energy -To replenish the fossil fuels we have depleted so far would take millions of years

4. © 2011 Pearson Education, Inc. Fossil fuels are created from fossils Fossil fuels were formed from organisms that lived 100–500 million years ago Aerobic decomposition = organic material is broken down and recycled in the presence of air Anaerobic decomposition = occurs with little or no air -Deep lakes, swamps -Produces fossil fuels

5. © 2011 Pearson Education, Inc. Regions vary greatly in energy consumption The U.S. has 4.5% of the population but uses 20% of the world’s energy

6. © 2011 Pearson Education, Inc. It takes energy to make energy We don’t get energy for free Energy returned on investment (EROI) = energy returned/energy invested -Higher ratios mean we receive more energy than we invest Net energy = the difference between energy returned and energy invested -Net energy = energy returned – energy invested

7. © 2011 Pearson Education, Inc. Coal The world’s most abundant fossil fuel -Created 300–400 million years ago -US has most reserves Coal = organic matter (woody plant material) -Compressed under very high pressure in swamps to form dense, solid carbon structures -Very little decomposition occurred

8. © 2011 Pearson Education, Inc. Coal is mined using two major methods Strip mining = for deposits near the surface -Heavy machinery removes huge amounts of earth to expose the coal Subsurface mining = underground deposits are reached by digging tunnels to follow seams (layers) of coal Mountaintop removal = entire mountaintops are cut off -Environmentally destructive -Common in the Appalachian Mountains

9. © 2011 Pearson Education, Inc. A typical coal-fired power plant

10. © 2011 Pearson Education, Inc. Coal varies in its qualities Coal varies in water and carbon content and its amount of potential energy Peat = organic material that is broken down anaerobically -It is wet, near the surface, and not well compressed Additional pressure, heat, and time turn peat into coal -Lignite = least compressed -Sub-bituminous and bituminous -Anthracite = most compressed and has the most energy

11. © 2011 Pearson Education, Inc. Coal contains impurities It has sulfur, mercury, arsenic, and other trace metals The sulfur content depends on whether coal was formed in salt water or freshwater -Coal in the eastern U.S. is high in sulfur because it was formed in marine sediments The Earth holds enough coal to last a few hundred years

12. © 2011 Pearson Education, Inc. Natural gas burns more cleanly than coal The fastest growing fossil fuel in use today It is versatile and clean-burning -Emits ½ as much CO 2 as coal, ⅔ as much as oil Liquefied natural gas (LNG) = gas converted to liquid Russia holds the most natural gas -The U.S. leads the world in use World supplies are projected to last about 60 more years Natural gas = methane (CH 4 ) and other volatile hydrocarbons Kerogen = organic matter that results when carbon bonds begin breaking -Source material for natural gas and crude oil

13. © 2011 Pearson Education, Inc. Heat and pressure form petroleum Oil is the world’s most used fuel -35% of world’s energy use -The U.S. uses the most, but China’s and India’s use is increasing -Nearly 67% of the world’s reserves lie in the Middle East Crude oil (petroleum) = a mixture of hundreds of different types of hydrocarbon molecules -Formed 1.5–3 km (1–2 mi) underground -Dead organic material was buried in marine sediments and transformed by time, heat, and pressure

14. © 2011 Pearson Education, Inc. Not all oil can be extracted Some oil is so hard to extract, it is not worth the cost -As prices rise, economically recoverable amounts approach technically recoverable amounts Technology limits what can be extracted -Economics determines how much will be extracted Proven recoverable reserve = the amount of oil (or any other fossil fuel) that is technically and economically feasible to remove under current conditions

15. © 2011 Pearson Education, Inc. We drill to extract oil Exploratory drilling = small, deep holes to determine whether extraction should be done Primary extraction = the initial drilling and pumping of available oil Secondary extraction = solvents, water, or steam is used to remove additional oil, but it is expensive

16. © 2011 Pearson Education, Inc. Oil refineries create petroleum products Refining = hydrocarbons are separated into different size classes and are chemically transformed -Creating specialized fuels for many uses

17. © 2011 Pearson Education, Inc. U.S. oil production has already peaked

18. © 2011 Pearson Education, Inc. Canada is mining oil sands Oil sands (tar sands) = sand deposits with bitumen -A form of petroleum rich in carbon, poor in hydrogen -Degraded and chemically altered crude oil deposits Removed by strip mining Requires special extraction and refining processes Most is in Venezuela and Alberta

19. © 2011 Pearson Education, Inc. Oil shale is abundant in the U.S. west Oil shale = sedimentary rock filled with kerogen (organic matter) -Can be burned like coal or baked in the presence of hydrogen (called pyrolysis) to extract liquid petroleum World’s supplies may equal 600 billion barrels -40% is in the U.S., mostly on federally owned land in Colorado, Wyoming, and Utah Low prices for crude oil have kept investors away -But as oil prices increase, oil shale is attracting interest

20. © 2011 Pearson Education, Inc. Fossil fuel emissions pollute Carbon dioxide is released into the air -Driving changes in global climate Emissions cause severe health problems -Cancer, irritation, poisoning Technology and legislation can reduce pollution Carbon dioxide is the greatest impact of fossil fuel use

21. © 2011 Pearson Education, Inc. Clean coal technologies Clean coal technologies = technologies, equipment, and approaches to remove chemical contaminants while generating electricity from coal Scrubbers chemically convert or remove pollutants -Removing sulfur dioxide or nitrogen oxides Coal that contains lots of water can be dried Gasification = coal is converted into cleaner synthesis gas (syngas) -Which can be used to turn a gas or steam turbine These technologies have reduced pollution -But clean coal is still a dirty way to generate power

22. © 2011 Pearson Education, Inc. Coal mining devastates natural systems Acid drainage = chemical runoff from strip mining enters waterways -Sulfuric acid leaches metals from rocks -U.S. regulations require companies to restore strip- mined land, but complete restoration is impossible Mountaintop removal removes tons of rock and soil -Destroying immense amounts of habitat and creeks Loosening of regulations in 2002 allowed companies to legally dump debris into valleys and rivers -Regardless of the consequences

23. © 2011 Pearson Education, Inc. How will we convert to renewable energy? Fossil fuel supplies are limited, and their use has consequences Nations have several options for future energy use: -Continue relying on fossil fuels until they are no longer economically practical -Immediately increase funding to develop alternative energy sources dramatically -Steer a middle course and gradually reduce our reliance on fossil fuels We need to prolong fossil fuels through conservation

24. © 2011 Pearson Education, Inc. Energy efficiency and conservation We need to minimize energy use from dwindling fossil fuel supplies Energy efficiency = obtaining a given amount of output while using less energy input -Results from technological improvements Energy conservation = reducing energy use -Results from behavioral choices We can extend our nonrenewable energy supplies -Be less wasteful -Reduce our environmental impact

25. © 2011 Pearson Education, Inc. Personal choice and efficiency Energy conservation can be accomplished in two ways Individuals can make conscious choices to reduce energy consumption and increase conservation -Drive less, turn off lights, buy efficient machines Energy-consuming devices can be made more efficient -Cars and power plants lose ⅔ of energy as waste heat

26. © 2011 Pearson Education, Inc. We already have the technology we need The U.S. has become more efficient, but we can do better -Cars: efficient engines, electric cars, hybrids, etc. Cogeneration = excess heat produced during electrical generation is used to heat buildings -Or produce other types of power -It can double the efficiency of a power plant

27. © 2011 Pearson Education, Inc. Efficiency in homes and consumer products Improvements can reduce energy to heat and cool homes Appliances have been reengineered to increase efficiency Federal standards reduce electricity used Consumers need to vote with their wallets by buying energy-efficient products If all Americans bought energy-efficient appliances, U.S. energy expenditures would be reduced by $200 billion

28. © 2011 Pearson Education, Inc. QUESTION: Review Which energy source is versatile and emits the least CO 2 ? a)Coal b)Natural gas c)Petroleum d)None of the above

29. © 2011 Pearson Education, Inc. QUESTION: Review Which of the following describes when heavy machinery removes huge amounts of earth to expose coal? a) Strip mining b) Subsurface mining c) Mountaintop removal d) Illegal mining

30. © 2011 Pearson Education, Inc. QUESTION: Review Which of the following does NOT describe natural gas that has been formed biogenically? a)It was created in shallow water. b)It was created by bacteria. c)It is also called swamp gas. d)It was created deep underground.

31. © 2011 Pearson Education, Inc. QUESTION: Review _____ contains the most oil in the world, while ______ consumes the most a)Mexico, Japan b)Kuwait, France c)Saudi Arabia, the United States. d)The United States, the United States.

32. © 2011 Pearson Education, Inc. QUESTION: Review It is estimated that we have already depleted ___% of our global oil reserves. a)25% b)50% c)75% d)100%

33. © 2011 Pearson Education, Inc. QUESTION: Review Which statement about peak oil is NOT correct? a)The United States has reached peak oil. b)Production declines once reserves are 75% depleted. c)Discoveries of new fields peaked 30 years ago. d)We are using more oil than we are discovering.

34. © 2011 Pearson Education, Inc. QUESTION: Review What is a major problem of oil shale and tar sands? a)Mining for them destroys the land. b)They release greenhouse gases. c)Mining and using them releases pollution. d)All of these are major problems of these sources of energy.

35. © 2011 Pearson Education, Inc. QUESTION: Weighing the Issues How is your life affected as oil becomes more expensive? What will you do? a)I will start conserving gasoline by walking more or carpooling. b)I need my car, so I will just have to earn more money. c)It won’t affect me, because I already minimize my driving. d)It won’t affect me, because I have enough money to afford gasoline.

36. © 2011 Pearson Education, Inc. QUESTION: Weighing the Issues Should the government raise taxes on gasoline to reflect its true cost? a)Yes; that would make people conserve gasoline. b)Yes, but poor people would need subsidies to help them buy gasoline. c)No; I don’t want to pay more for gasoline. d)I don’t care; I have enough money to pay for expensive gasoline.

37. © 2011 Pearson Education, Inc. QUESTION: Interpreting Graphs and Data According to this graph, the contribution of oil from ANWR over the next 50 years will be: a)Extremely significant b)Extremely insignificant c)Very high d)Worth drilling for

38. © 2011 Pearson Education, Inc. QUESTION: Interpreting Graphs and Data According to this graph, what would you best conclude? a)Fuel efficiency can increase in the United States. b)U.S. efficiency goes only upward. c)Fuel efficiency is not possible in the United States. d)The United States does not need efficiency.