Module 3 PEE PDF

People and the Earth’s Ecosystems Module 3 Renewable and Non-renewable Resources Module Overview: This part of module introduces renewable and non-renewable resources that the planet Earth offers for human use. Module Outcomes: At the e...

People and the Earth’s Ecosystems Module 3 Renewable and Non-renewable Resources Module Overview: This part of module introduces renewable and non-renewable resources that the planet Earth offers for human use. Module Outcomes: At the end of the lessons, students should be able to: Describe how human uses the Earth’s resources; Distinguish non-renewable from renewable energy resource 77 | P a g e  People and the Earth’s Ecosystems Lesson 1 People and the Forest Learning Outcomes Define sustainable forestry and explain how monocultures and wildlife corridors are related to it. Define deforestation, including clearcutting, and list the main causes of tropical deforestation. Describe national forests and state which government agencies administer them and current issues of concern. Time Frame: 1 week Introduction This lesson talks about the how forest corridors help in sustainable farming, and the incidence of deforestation around the globe. Activity 1. What is sustainable forestry? 2. What is deforestation? What are four important causes of tropical deforestation? Abstraction FORESTS and their ROLES Provide many goods and services to support human society occupy less than one-third of Earth’s total land area. Timber harvested from forests is used for fuel construction materials, and paper products. supply nuts, mushrooms, fruits, and medicines. provide employment for millions of people worldwide and offer recreation and spiritual sustenance in an increasingly crowded world. 78 | P a g e  People and the Earth’s Ecosystems Role of forests in the hydrologic cycle regulating global biogeochemical cycles like those for carbon and nitrogen Photosynthesis by trees removes large quantities of heat-trapping carbon dioxide from the atmosphere and fixes it into carbon compounds, while releasing oxygen back into the atmosphere. act as carbon “sinks,” which may help mitigate climate warming, produce oxygen for cellular respiration of organisms Tree roots hold vast tracts of soil in place, reducing erosion and mudslides protect watersheds; moderation of water flow provides a more regulated flow of water downstream Forest soils remove impurities from water, improving its quality. provide a variety of essential habitats for many organisms Forest Management Management for timber production disrupts a forest’s natural condition and alters its species composition and other characteristics. Monoculture- Ecological simplification in which only one type of plant is cultivated over a large area. Disadvantage of monocultures: at increased risk of damage from insect pests and disease-causing microorganisms. Sustainable forestry- the use and management of forest ecosystems in an environmentally balanced and enduring way 79 | P a g e  People and the Earth’s Ecosystems wildlife corridor- A protected zone that connects isolated unlogged or undeveloped areas. Harvesting Trees about 3.5 million m3 (120 million ft3) of wood are harvested annually (forfuelwood, timber, and other products) 5 countries with the greatest tree harvests: United States, Canada, Russia, Brazil, and China About 50% of harvested wood is burned directly as fuelwood or used to make charcoal. Harvesting trees Selective cutting- mature trees are cut individually or in small clusters while the rest of the forest remains intact, allows the forest to regenerate naturally. shelterwood cutting- The removal of all mature trees in an area over an extended period. In the first year of harvest, undesirable tree species and dead or diseased trees are removed. Subsequent harvests occur at intervals of several years, allowing time for remaining trees to grow. seed tree cutting- almost all trees are harvested from an area; a scattering of desirable trees is left behind to provide seeds for the regeneration of the forest. 80 | P a g e  People and the Earth’s Ecosystems clear-cutting A logging practice in which all the trees in a stand of forest are cut, leaving just the stumps. Deforestation The temporary or permanent clearance of large expanses of forest for agriculture or other uses. Causes of the decades-long trend of deforestation include fires caused by drought and land clearing practices, expansion of agriculture, construction of roads, tree harvests, insects, disease, and mining. Most of the world’s deforestation is currently taking place in Africa and South America Results of Deforestation decreased soil fertility Uncontrolled soil erosion Increased sedimentation of waterways caused by soil erosion harms downstream fisheries. formation of deserts Disruption of Regulation of water flow → alternating periods of flood and drought extinction of many species habitat modification and destruction regional and global climate changes increase in global temperature by releasing carbon originally stored in the trees into the atmosphere as carbon dioxide Boreal Forests and Deforestation Extensive deforestation in boreal forests due to logging began in the late 1980s. Boreal forests 81 | P a g e  People and the Earth’s Ecosystems occur in Alaska, Canada, Scandinavia, and northern Russia and are dominated by coniferous evergreen trees such as spruce, fi r, cedar, and hemlock. the world’s largest, covering about 11% of Earth’s land. primary source of the world’s industrial wood and wood fi ber. Tropical Forests and Deforestation two types of tropical forests: tropical rain forests and tropical dry forests. Tropical rain forests prevail in warm areas that receive 200 cm (79 in) or more of precipitation annually. are found in Central and South America, Africa, and Southeast Asia, but almost half of them are in just three countries: Brazil, Democratic Republic of the Congo, and Indonesia Tropical dry forests occur in other tropical areas where annual precipitation is less but is still enough to support trees. India, Kenya, Zimbabwe, Egypt, and Brazil Why are tropical rain forests disappearing? Population growth Deforestation Agricultural expansion economic, social, and government factors 3 agents: subsistence agriculture, commercial logging, and cattle ranching For fuelwood Wood as heating and cooking fuel wood cut for fuel is converted to charcoal, which is then used to power steel, brick, and cement factories. 82 | P a g e  People and the Earth’s Ecosystems Application What is happening in this picture? Julia “Butterfly” Hill lived in this 600–1,000-year-old, 180-foot-tall California redwood for more than 2 years in the late 1990s, to keep a lumber company from cutting down the tree. 1. Would Hill’s perspective on wilderness better fit the wise-use movement or the environmental movement? 2. Explain the likely differences in the perspectives of Hill and the lumber company, especially given that the tree is on the company’s land. 3. Based on issues faced in Tongass National Forest, why do ecologists and environmentalists think that the logging of old-growth trees causes particular damage? Closure The next lesson talks about the water resources. 83 | P a g e  People and the Earth’s Ecosystems Lesson 2 People and waters Learning Outcomes Explain how processes of the hydrologic cycle allow water to circulate through the abiotic environment. Relate some of the problems caused by aquifer depletion, overdrawing of surface waters, and salinization of irrigated soil. Define water pollution. Discuss how sewage is related to eutrophication, biochemical oxygen demand (BOD), and dissolved oxygen. Describe sources of groundwater pollution. Describe the global ocean and its significance to life on Earth. Define El Niño–Southern Oscillation (ENSO) and La Niña and describe some of their effects. Time Frame: 1 week Introduction This lesson talks about the water resources and how humans utilize them. This will also tackle the effects of development in the fresh and marine waters. Activity 1. How do processes in the hydrologic cycle affect the accumulation of groundwater? 2. How do hydrogen bonds form between adjacent water molecules? 3. What are two unique properties of water? 4. What is water pollution? 5. What is biochemical oxygen demand? How is BOD related to sewage? 6. How does point source pollution differ from nonpoint source pollution? What are some examples of each? 7. What are some common sources of groundwater pollutants? Abstraction The Importance of Water All life forms, from unicellular bacteria to multicellular plants and animals, contain water. Humans are composed of approximately 60 percent water by body weight. Drinking water 84 | P a g e  People and the Earth’s Ecosystems agriculture, manufacturing, mining, energy production, and waste disposal. 97%-saltwater Fresh water is distributed unevenly The Hydrologic Cycle and Our Supply of Fresh Water In the hydrologic cycle, water continuously circulates through the environment, from the ocean to the atmosphere to the land and back to the ocean hydrologic cycle provides a continual renewal of the supply of fresh water on land surface water- Precipitation that remains on the surface of the land and does not seep down through the soil. Runoff- The movement of fresh water from precipitation and snowmelt to rivers, lakes, wetlands, and the ocean. drainage basin, or watershed- the area of land drained by a single river or stream Groundwater- The supply of fresh water under Earth’s surface that is stored in underground aquifers. Aquifers- underground reservoirs in which groundwater is stored Properties of Water Consisting of two atoms of hydrogen and one atom of oxygen. polar high melting/ freezing point (0°C, 32°F) High boiling point (100°C, 212°F) 85 | P a g e  People and the Earth’s Ecosystems most water exists in the liquid form organisms need. high heat capacity A solvent In nature, water is never completely pure because it contains dissolved gases from the atmosphere and dissolved mineral salts from the land. Water Pollution A physical or chemical change in water that adversely affects the health of humans and other organisms. eight categories: sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution. Types of Water Pollution 86 | P a g e  People and the Earth’s Ecosystems Eutrophication: An Enrichment Problem Oligotrophic- Lakes, estuaries, and slow-fl owing streams that have minimal levels of nutrients; Supports small populations of aquatic organisms Eutrophication- enrichment of a lake, an estuary, or a slow-flowing stream by inorganic plant and algal nutrients such as phosphorus; Eutrophic- an enriched body of water→ increased photosynthetic productivity; presence of vast numbers of algae and cyanobacteria Artificial Eutrophication- Overnourishment of an aquatic ecosystem by nutrients such as nitrates and phosphates due to human activities such as agriculture and discharge from sewage treatment plants. 87 | P a g e  People and the Earth’s Ecosystems Sources of Water Pollution come from both natural sources and human activities 2 SOURCES: Point source pollution- is discharged into the environment through pipes, sewers, or ditches from specific sites such as factories or sewage treatment plants; relatively easy to control legislatively, but accidents still occur. nonpoint source pollution- Pollution that enter bodies of water over large areas rather than being concentrated at a single point of entry. polluted runoff- Pollutants that enter bodies of water over large areas rather than at a single point cause nonpoint source pollution, also called polluted runoff Groundwater Pollution drinking water from groundwater, is also withdrawn for irrigation and industry. The most common pollutants, such as pesticides, fertilizers, and organic compounds, seep into groundwater from municipal sanitary landfi lls, underground storage tanks, backyards, golf courses, and intensively cultivated agricultural lands The Global Ocean ocean is a vast wilderness It teems with life—from warmblooded mammals such as whales to softbodied invertebrates such as jellyfish. It is essential to the hydrologic cycle that provides water It affects cycles of matter on land, influences our climate and weather, and provides foods that enable millions of people to survive.. Patterns of Circulation in the Ocean Gyres- Large, circular ocean current systems that often encompass an entire ocean basin. Coriolis effect- influences the paths of surface, or shallow, ocean currents just as it does the winds Earth’s rotation from west to east causes surface ocean currents to swerve to the right in the Northern Hemisphere In the Southern Hemisphere, ocean currents swerve to the left, thereby moving in a circular, counterclockwise pattern Vertical Mixing of Ocean Water 88 | P a g e  People and the Earth’s Ecosystems Variations in the density (mass per unit volume) of seawater affect deep-ocean currents. Cold, salty water is denser than warmer, less salty water. Colder, salty ocean water sinks and flows under warmer, less salty water, generating currents far below the surface. ocean conveyor belt moves cold, salty deep-sea water from higher to lower latitudes, where it warms up. affects regional and possibly global climate shifts from one equilibrium state to another El Niño–Southern Oscillation El Niño–Southern Oscillation (ENSO)- A periodic, large-scale warming of surface waters of the tropical eastern Pacific Ocean that temporarily alters both ocean and atmospheric circulation patterns. Every 3 to 7 years, the trade winds weaken, and the warm mass of water expands eastward to South America, increasing surface temperatures in the usually cooler east Pacific During an ENSO event, however, the colder, nutrient-rich deep water is about 150 m (490 ft) below the surface, and the warmer surface temperatures and weak trade winds prevent upwelling 89 | P a g e  People and the Earth’s Ecosystems alters global air currents, directing unusual, sometimes dangerous, weather to areas far from the tropical Pacifi c where it originates 1997–1998 ENSO- the strongest on record, caused more than 20,000 deaths and $33 billion in property damage worldwide TAO/ TRITON array- instruments collect oceanic and weather data during normal conditions and El Niño events La Niña in Spanish, “the girl child” occurs when the surface water temperature in the eastern Pacific Ocean becomes unusually cool and westbound trade winds become unusually strong. often occurs after an El Niño event and is considered part of the natural oscillation of ocean temperature. typically causes wetter-than-usual winters in the Pacifi c Northwest, warmer weather in the Southeast, and drought conditions in the Southwest. Atlantic hurricanes are stronger and more numerous than usual during a La Niña event 90 | P a g e  People and the Earth’s Ecosystems Application https://r3.rappler.com/nation/special-coverage/weather-alert/263621-pagasa-rainy-season-philippines-2020 What is happening in this picture? Rain soaks the streets of Manila. 1. How might the hydrologic cycle be linked to potential groundwater pollution in this type of urban setting? 2. What unique property of water allows it to carry pollutants? 3. What about the structure of water molecules determines why water on Earth is most often found in this liquid form? Closure The next lesson talks about the climate. 91 | P a g e  People and the Earth’s Ecosystems Lesson 3 People and climate Learning Outcomes Distinguish between weather and climate. Summarize the effects of solar energy on Earth’s temperature. List the five main greenhouse gases and describe the enhanced greenhouse effect. Discuss some of the potential effects of global climate change. Give examples of strategies to mitigate or adapt to global climate change. Time Frame: 1 week Introduction In this lesson, we will be tackling here atmosphere and climate. Then we will proceed our discussion to the alarming changes of our global climate. Activity List down the top 10 dreadful typhoon that hit the Philippines in the last 10 years. Include the damages they caused to the people, to the properties and to the environment. You may present this with pictures. Typhoons Number of Extent of damage Extent of damage to families affected to the properties the environment 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 92 | P a g e  People and the Earth’s Ecosystems Analysis 1. From the above activity, what do you think are the causes of the devastations? ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ 2. List down 5 ways on how to mitigate the aftermath of these disasters. ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ ______________________________________________________________ Abstraction Atmosphere and Climate Earth’s atmosphere is a thin layer of mixed gases that extends upward approximately 500 km. It contains the air we breathe and protects us from the heat blast radiated from the sun. There are 4 distinct zones of the atmosphere based on the temperature: 1. troposphere – is in the lowest region closest to the Earth’s surface where most of the weather occurs. Weather includes temperature, 93 | P a g e  People and the Earth’s Ecosystems atmospheric pressure, precipitation, cloudiness, humidity, and wind. Climate is the typical weather patterns that occur in a place over a period of years. The uppermost layer of the troposphere is called tropopause. 2. stratosphere – approximately 18 km above tropopause which has almost no water vapor and nearly 1,000 times more ozone (O3). Near the earth’s surface ozone is a pollutant, but in the stratosphere it absorbs certain wavelengths of sun’s radiation, protecting life on the earth’s surface. The uppermost layer of stratosphere is called stratopause. 3. mesosphere (middle layer) – the coldest layer of the atmosphere which reaches approximately 80km above the earth’s surface. Meteors usually burn up in this region. 4. thermosphere (heated layer)– a region where aurora borealis (northern lights) and aurora australis (southern lights) occur. Earth absorbs heat radiation from the sun unequally across the globe. Near the equator receives more incoming solar radiation (insolation) than at high latitudes. This energy absorption warms the atmosphere slightly. About half of 94 | P a g e  People and the Earth’s Ecosystems insolation reaches the earth’s surface. Some of this energy is reflected by bright surfaces, such as snow, ice, and sand. The rest is absorbed by the earth’s surface and by water. Surfaces that reflect energy have a high albedo (reflectivity). Temperature Changes with Latitude and Season Earth’s inclination on its own axis causes seasons. From March 21 to September 21, the Northern Hemisphere tilts toward the Sun, and during September 22 to March 20, it tilts away from the Sun. This means that the 2 hemispheres always experience opposite seasons. Half of the year, the northern hemisphere receives more light from the sun than the southern hemisphere. And on the other half of the year, the southern hemisphere tilts the opposite way, so it receives more light than the northern hemisphere. Causes of Global Climate Change 1. Human Activities 95 | P a g e  People and the Earth’s Ecosystems https://climategamechanger.sg/2019/08/ https://metro.co.uk/2019/09/23/climate- https://education.seattlepi.com/effect- 14/causes-of-climate-change/ change-causes-effects-accelerating-warn- human-activities-environment-3653.html scientists-10790754/ Significant amount of carbon dioxide (CO2) through human activities such as deforestation, land use changes, and burning fossil fuels is released through the atmosphere. High nitrous oxide is also produced in cultivating the soil, fossil fuel combustion, landfills, and biomass burning. The widely use of Chlorofluorocarbons (CFCs), which are nontoxic, nonflammable chemicals, for various purposes. Greenhouse effect is the natural warming of the Earth’s surface that results from trapping the sun’s heat in the earth’s atmosphere. These gases in the atmosphere that keep the sun’s heat from escaping are called greenhouse gasses. Water vapor (H2O) is the most abundant greenhouse gas, and it is always present in the atmosphere. Carbon dioxide (CO2) is the most abundant human- caused greenhouse gas; followed by methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), and tropospheric ozone (O3) and dozens of other gases. Because of these gases, a rapid increase in temperature and amount of CO2 in the atmosphere have been observed in the last 50 years. 96 | P a g e  People and the Earth’s Ecosystems 2. Volcanic eruption - During volcanic eruption, huge amount of natural aerosols like carbon dioxide, sulfur dioxides, salt crystals, volcanic ashes or dust, and even microorganisms like bacteria and viruses are released to the atmosphere. Some of these aerosols have effect on our climate pattern but in short period only. 3. Orbital Changes - the earth’s movement around the sun can also cause climate change as proposed by the Milankovitch theory though its impact is considered as insignificant in our present climate patterns. Effects of Climate Change Global temperature rise Warming ocean Shrinking ice sheets Glacial retreat Decreased snow cover Rise of sea level Left: Shrinking ice sheets. Right: Decreased snow cover Source: https://climate.nasa.gov/evidence/ Declining Arctic Sea ice Extreme Events Ocean Acidification Declining Arctic Sea ice. https://www.nasa.gov/feature/goddard/2019/arcti c-sea-ice-2019-wintertime-extent-is-seventh- Typhoon Ulysses. https://www.topgear.com.ph/news/motoring- lowest news/typhoon-ulysses-markina-city-a962-20201112 97 | P a g e  People and the Earth’s Ecosystems Mitigation of Global Climate Change: Developing alternatives to fossil fuels Reducing energy use Energy-pricing Strategies Planting and maintaining forests Innovating technology for carbon management Increasing efficiency of coal- fired power plants Increasing fuel economy of motor vehicles Redesigning cities to reduce reliance on single occupant vehicles Insulating buildings to reduce the need for heating in the winter and cooling in the summer Adaptation to Global Climate Change On one of the most pressing issues - rising sea level. 98 | P a g e  People and the Earth’s Ecosystems People living in coastal areas could be moved inland, away from the dangers of storm surges. Construction of massive sea walls to protect coastal land. Countries with temperate climates are evaluating semitropical crops to determine the best substitutes for traditional crops as the climate warms. Large lumber companies are developing heat- and drought-resistant strains of trees that will be harvested when global climate change may be well advanced. Application 1. Describe the weather patterns where you live. __________________________________________________________ __________________________________________________________ __________________________________________________________ 2. Will it be easier for societies to mitigate climate change or to adapt to a changed climate? Explain your answer. ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ 3. Most of us find it difficult to contemplate global climate change. The potential effects are so disastrous and the time scale is so long that we simply put it out of our minds. How can we frame the issue in positive, practical terms that people can do something about immediately? ___________________________________________________________ ___________________________________________________________ ___________________________________________________________ 99 | P a g e  People and the Earth’s Ecosystems Lesson 4 Energy Learning Outcomes Distinguish non-renewable from renewable energy resources Time Frame: 1 week Introduction Welcome students to this last lesson of the course that talks about renewable and non-renewable energy resources. Activity 1. Create a check-list of the energy you use at home? 2. What renewable energy sources does your home use? 3. How can you help to lessen the use of non-renewable energy and use more of renewable one? Do you think renewable energy is more environmentally friendly? Account for this. Abstraction Energy Consumption Human society depends on energy. World energy consumption has increased every year since 1982, with most of the increase occurring in developing countries. Coal ▪ the most abundant fossil fuel in the world ▪ found primarily in the Northern Hemisphere ▪ The largest coal deposits are in the United States, Russia, China, Australia, India, Germany, and South Africa Coal Mining 2 basic types of coal mines: surface and subsurface (underground) mines. surface mining- extraction of mineral and energy resources near Earth’s surface by first removing the soil, subsoil, and overlying rock strata. subsurface mining- extraction of mineral and energy resources from deep underground deposits. Environmental Impacts of Coal acid mine drainage- Pollution caused when sulphuric acid and dangerous dissolved materials, such as lead, arsenic, and cadmium, wash from coal and metal mines into nearby lakes and streams. One of the most land- destructive types of surface mining is mountaintop removal. 100 | P a g e  People and the Earth’s Ecosystems Dangerous landslides occurred on hills that were unstable due to the lack of vegetation Coal burning generally contributes more of the common air pollutants than burning either oil or natural gas. acid deposition- coal contains sulfur and nitrogen that, when burned, are released into the atmosphere as sulfur oxides (SO2 and SO3) and nitrogen oxides (NO, NO2, and N2O), many of which form acids when they react with water. Burning coal causes a more severe CO2 problem than burning other fossil fuels because coal releases more CO2 per unit of heat energy produced than does burning either oil or natural gas. Making Coal Cleaner fluidized-bed combustion- A clean-coal technology in which crushed coal is mixed with limestone to neutralize acidic compounds produced during combustion. In the United States several large power plants are testing fluidized- bed combustion, and a few small plants are already using this technology. The Clean Air Act Amendments of 1990 provide incentives for utility companies to convert to clean coal technologies. Oil and Natural Gas Petroleum, or crude oil, is a liquid composed of hundreds of hydrocarbon compounds. Oil is also used to produce petrochemicals, compounds used to make products such as fertilizers, plastics, paints, pesticides, medicines, and synthetic fibers. During petroleum refining, the compounds are separated into different products—such as gases, jet fuel, heating oil, diesel, and asphalt— based on their different boiling points natural gas contains only a few hydrocarbons: methane and smaller amounts of ethane, propane, and butane. Propane and butane are separated from the natural gas, stored in pressurized tanks as a liquid called liquefied petroleum gas, and used primarily in rural areas as fuel for heating and cooking. Methane is used to heat residential and commercial buildings, to generate electricity in power plants, and for a variety of purposes in the organic chemistry industry. Natural gas use is increasing in three main areas: electricity generation, transportation, and commercial cooling. Natural gas is often used in cogeneration, a clean and efficient process in which natural gas is used to produce both electricity and steam; the heat of the exhaust gases provides energy to make steam for water and space heating Natural gas efficiently fuels residential and commercial air-cooling systems Natural gas use is increasing in three main areas: electricity generation, transportation, and commercial cooling. Natural gas is often used in cogeneration, a clean and efficient process in which natural gas is used to produce both electricity and 101 | P a g e  People and the Earth’s Ecosystems steam; the heat of the exhaust gases provides energy to make steam for water and space heating Natural gas efficiently fuels residential and commercial air-cooling systems Environmental Impacts of Oil and Natural Gas Extracting, transporting, and burning oil and natural gas create a variety of environmental problems. burning oil and natural gas produces CO2 that contributes to global climate change. Burning oil also leads to acid deposition and the formation of photochemical smog. Natural gas, on the other hand, is a relatively clean, efficient source of energy that contains almost no sulphur and releases far less CO2, fewer hydrocarbons, and almost no particulate matter compared to oil and coal. One risk of oil and natural gas production relates to their transport, often over long distances by pipelines or ocean tankers. Natural gas leaks, while rare, can lead to massive explosions. Oil spills create environmental damage, particularly in aquatic ecosystems, where an oil slick can travel great distances. Nuclear Energy The energy released by nuclear fission or fusion. Involves changes in the nuclei of atoms; small amounts of matter from the nucleus are converted into large amounts of energy. Nuclear reactions produce 100,000 times more energy per atom than is available from a chemical bond between two atoms. Fission- The splitting of an atomic nucleus into two smaller fragments, accompanied by the release of a large amount of energy. Fusion- two small atoms are combined, forming one larger atom of a different element Conventional Nuclear Fission Uranium ore mineral fuel used in conventional nuclear power plants nonrenewable resource present in limited amounts in sedimentary rock in Earth’s crust. Uranium ore contains three isotopes: U-238 (which makes up 99.28 % of uranium), U-235 (0.71 %), and U-234 (less than 0.01 %). 102 | P a g e  People and the Earth’s Ecosystems Enrichment- The process by which uranium ore is refined after mining to increase the concentration of fissionable U-235. After enrichment, uranium is processed into small pellets of uranium dioxide; each pellet contains the energy equivalent of 1 ton of coal The pellets are then placed in closed pipes, often as long as 3.7 m (12 ft), called fuel rods. The fuel rods are grouped into square fuel assemblies, generally made up of 200 rods each nuclear reactor –A device that initiates and maintains a controlled nuclear fission chain reaction to produce energy for electricity.A typical nuclear reactor contains 150 to 250 fuel assemblies. A typical nuclear power plant has four main parts: the reactor core, the steam generator, the turbine, and the condenser Nuclear fission occurs in the reactor core, and the heat produced by fission is used to produce steam from liquid water in the steam generator. The turbine uses the steam to generate electricity, and the condenser cools the steam, converting it back to a liquid. Nuclear Energy and Fossil Fuels Worldwide, nuclear power production is steadily increasing. In part, this is due to concerns about climate change, but it is primarily driven by an increasing demand for energy. nuclear energy emits few pollutants into the atmosphere. Nuclear energy can also provide power without producing climate altering CO2. spent fuel- Used fuel elements that were irradiated in a nuclear reactor Nuclear power Plants produce radioactive coolant fl uids and gases in the reactor Which are extremely dangerous, and the hazards of their health and environmental impacts require that special measures be taken to ensure their safe storage and disposal. At high temperatures, the metal encasing uranium fuel can melt, releasing radiation; this is called a meltdown water used in a nuclear reactor to transfer heat can boil away during an accident, contaminating the atmosphere with radioactivity. Nuclear power risks are involuntary and potentially catastrophic Radioactive Wastes classified as either “low level” or “high level.” low-level radioactive wastes - Solids, liquids, or gases that give off small amounts of ionizing radiation. high-level radioactive wastes - Radioactive solids, liquids, or gases that initially give off large amounts of ionizing radiation. Direct Solar Energy sun produces a tremendous amount of energy, most of which dissipates into space. Only a small portion is radiated to Earth. Solar energy differs from fossil and nuclear fuels in that it is always available; Solar energy will deplete only when the sun’s nuclear fire burns out. Heating Buildings and Water 103 | P a g e  People and the Earth’s Ecosystems active solar heating - A system of putting the sun’s energy to use in which collectors absorb solar energy and pumps or fans distribute the collected heat. active solar heating - A system of putting the sun’s energy to use in which collectors absorb solar energy and pumps or fans distribute the collected heat. passive solar heating- A system of putting the sun’s energy to use that does not require mechanical devices to distribute the collected heat. Photovoltaic Solar Cells A wafer or thin film of solid-state materials, such as silicon or gallium arsenide, that is treated with certain metals in such a way that the film generates electricity when solar energy is absorbed. Photovoltaics generate energy that can pump water, refrigerate vaccines, grind grain, charge batteries, and supply rural homes with lighting. PVs creates no air or water pollution but the manufacturing process requires industrial chemicals, many of which are toxic A means of producing electricity in which the sun’s energy is concentrated using mirrors or lenses onto a fluid-filled pipe; the heated fluid is used to generate electricity. are inherently more efficient than other solar technologies because they concentrate the sun’s energy. Hydrogen is a clean fuel; it produces water and heat as it burns, but it produces no sulfur oxides, carbon monoxide, hydrocarbon particulates, or CO2 emissions. It does produce some nitrogen oxides, though in amounts fairly easy to control Hydrogen has the potential to provide energy for transportation (in the form of hydrogenpowered automobiles) as well as for heating buildings and producing electricity. fuel cell - A device that directly converts chemical energy into electricity. A fuel cell requires hydrogen and oxygen from the air. Indirect Solar Energy Some renewable energy sources indirectly use the sun’s energy. Combustion of biomass (organic matter) is an example of indirect solar energy because plants use solar energy for photosynthesis and store the energy in biomass. 104 | P a g e  People and the Earth’s Ecosystems Windmills, or wind turbines, use wind energy to generate electricity. The damming of rivers and streams to generate electricity is a type of hydropower—the energy of flowing water. Biomass Energy biomass - Plant and animal material used as fuel. Biomass fuel, which may be a solid, liquid, or gas, is burned to release its energy. Solid biomass fuels such as wood, charcoal (wood turned into coal by partial burning), animal dung, and peat (partly decayed plant matter found in bogs and swamps) supply a substantial portion of the world’s energy. Biogas- usually composed of a mixture of gases (mostly methane), is like natural gas. It is a clean fuel—its combustion produces fewer pollutants than either coal or biomass biogas digesters use microbial decomposition of household and agricultural wastes to produce biogas for cooking and lighting When biogas conversion is complete, the solid remains are removed from the digester and used as fertilizer. Biomass can also be converted into liquid fuels, especially methanol (methyl alcohol) and ethanol (ethyl alcohol), which can replace gasoline in internal combustion engines. Bio diesel- made from plant or animal oils Wind Energy wind energy- Electric energy obtained from surface air currents caused by the solar warming of air Wind produces no waste and is a clean source of energy. It produces no emissions of sulfur dioxide, carbon dioxide, or nitrogen oxides. Every kilowatt-hour of electricity generated by wind power rather than fossil fuels prevents as much as 1 kg (2.2 lb) of the greenhouse gas CO2 from entering the atmosphere. one concern is the deaths of birds and bats. 105 | P a g e  People and the Earth’s Ecosystems Hydropower A form of renewable energy that relies on flowing or falling water to generate electricity. more effi cient than any other energy source for producing electricity; about 90 % of available hydropower energy is converted into consumable electricity. form of solar energy in greatest use 10 countries with the greatest hydroelectric production are: (decreasing order) Canada, the United States, Brazil, China, Russia, Norway, Japan, India, Sweden, and France Disadvantages: Building a dam changes the natural flow of a river: Water backs up, flooding large areas of land and forming a reservoir, which destroys plant and animal habitats. Native fishes are particularly being harmed by dams because the original river ecosystem is so altered. The migration of spawning fish is also altered Below the dam, the once-powerful river is reduced to a relative trickle. The natural beauty of the countryside is affected, and certain forms of wilderness recreation are made impossible or less enjoyable, although the dams permit water sports in the reservoir. Other Renewable Energy Sources Geothermal energy- Energy from Earth’s interior, used for space heating or generation of electricity. typically associated with volcanism 106 | P a g e  People and the Earth’s Ecosystems considered environmentally benign because it emits only a fraction of the air pollutants released by conventional fossil fuel–based energy technologies. The most common environmental hazard is the emission of hydrogen sulfide (H2S) gas, which comes from the very low levels of dissolved minerals and salts found in the steam or hot water. Tidal Energy A dam built across a bay can harness the energy of large tides to generate electricity. As the tide falls, water fl owing back to the ocean over the dam’s spillway turns a turbine and generates electricity through tidal energy. Cannot become a significant resource worldwide because few areas experience large enough differences in water level between high and low tides to make power generation feasible Disadvantages: high cost of building a tidal power station and potential environmental problems associated with tidal energy in estuaries Application What is happening in this picture? These pipes suck methane, which is used as fuel, from decomposing trash in Payatas, Quezon. 1. Is this a renewable energy source? a form of conservation? Explain. 2. What would be some advantages and disadvantages of this type of energy production? 107 | P a g e