tes I. SOIL AND FORESTS (pupil Edition pages 87-88)

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1 ! I C H P'T ER Resources and Environmental Change Lee tes I. SOIL AND FORESTS (pupil Edition pages 87-88) A. Soil 1. Throughout history, people have developed ways to conserve and enrich the soil. a. Terraced rice paddy is an example of how farmers preserved soil and stored water. b. Fertility of soil can be preserved by using natural fertilizers and through crop rotation. 2. Soil salinization is the buildup of salt in the soil. a. Evaporation of irrigated water leaves salt behind. b. Salinization becomes destructive to crops and eventually destroys the soil. 3. Desertification has resulted in many nations losing their soil. a. The loss of plant cover and soil eventually leads to desert-like conditions. b. In developing countries, desertification is primarily the result of overgrazing and the removal of trees over years. B. Forests 1. Forests are a valuable renewable resource. 2. Steps to conserve our forests by our federal government started in the early 1900s. a. Declared certain areas as national forests b. Reforestation, renewing forests through the planting of seeds or young trees, required in national forests that are logged 3. Deforestation, or the clearing of forests, is occurring at a rapid rate in the tropical rain forests of Asia, Africa, and Latin America. a. Logging of tropical hardwoods b. Burning and clearing for farmland and pastures c. Cutting for fuel 4. In northwestern North America, the native temperate forests are being logged at a rapid rate. The United States Forest Service was established in Gifford Pinchot was its first chief This agency was given control of the forest reserves (wooded areas set aside by the president in 1891). In 1907, these reserves became known as national forests. Today, national forests cover about 187 million acres (75.7 million hectares) of land. 33

2 I Sustained )ield use of resources ensures that a forest is,..,'"ell managed and remains a renewable resource. II. WATER AND AIR (pupil Edition pages 89-93) A. Water quantity 1. Water quantity and quality are serious challenges in many areas of the world. 2. Some countries rely on desalinization plants, which change salty seawater into fresh water. 3. Droughts cause water shortages. B. Flood control 1. Floods have killed millions of people over the centuries. 2. Dams and levees are built to control flood waters. c. Water quality 1. In developing nations, sewage often comes in contact with the drinking-water supply. 2. In developed countries, water is contaminated by industrial chemicals, fertilizers, pesticides, metals, and oil. 3. Oceans are the final dumping ground for some human waste. D. Air pollution 1. Air pollution is a serious problem facing many large urban and industrial areas. 2. Photochemical smog is produced when sunlight interacts with exhaust gases to produce visible and dangerous air pollution. 3. Acid rain is caused when acids released by industrial smokestacks combine with water vapor in the atmosphere. E. Global air pollution 1. Recent evidence indicates that the ozone layer has become depleted over the Antarctic, where there is a "hole" in the ozone layer. a. Skin cancer rates in the Southern Hemisphere have risen and scientists fear increased rates in North America and Europe. 34

3 b. Food chains in the rich Arctic and Antarctic waters may be damaged by increased ultraviolet radiation. c. The ozone layer is apparently destroyed when a group of chemicals called CFCs rise in the atmosphere and set off chemical reactions. 2. Another threat to the atmosphere is global warming caused by the greenhouse effect. a. Results from an apparent buildup of carbon dioxide in the lower atmosphere, which traps heat and causes long-term warming of the planet b. Some scientists warn that sea levels will rise, some types of vegetation will die, and entire ecosystems will be destroyed. c. Some scientists say that two ways to protect ourselves from the greenhouse effect are to decrease the burning of fuels that pollute and to stop cutting the world's forests. III. ENERGY RESOURCES (pupil Edition pages 93-95) A. Fossil fuels 1. Fossil fuels are nonrenewable resources that include coal, petroleum, and natural gas. 2. Fossil fuels are believed to have been formed from the buried remains of prehistoric plants and animals. 3. Coal a. From the Industrial Revolution until this century, coal was the major fossil fuel. b. Today, coal is burned to make electricity, is combined with iron ore to make steel, and is the source of many chemical products. c. Burning coal causes acid rain and air pollution. 4. Petroleum a. Along with natural gas, petroleum has replaced coal as the preferred energy source. b. Mainly used for liquid fuels, such as gasoline, diesel, and jet fuel c. Petroleum provides fuel oils for heat and electrical generation and is used in the production of petrochemicals. d. Petroleum is a nonrenewable resource, and the world supply may last only another 50 years. Earth Summit 1992 was held from June 3-14 in Rio de Janeiro, Brazil. Delegates from 178 nations and 117 heads of state attended the conference. A number of environmental issues were discussed, including sustainable development, or the reconciling of economic needs with environmental responsibility. 3S

4 - - - e. Largest petroleum reserves are found in Saudi Arabia and neighboring Persian Gulf countries 5. Natural gas a. Use is growing rapidly b. Largest reserves are in Russia and the Persian Gulf countries c. Cleanest-burning fossil fuel d. Can be shipped through pipelines e. Reserves are limited and may become scarce during the twenty-first century. the next several decades B. Nuclear energy 1. Today, there are more than 400 nuclear power plants in more than 30 nations. a. The United States has more than 100 operating nuclear power plants, and these plants produce about 20 percent of the nation's electricity. b. Nuclear power plants produce about half or more of the electricity in Ukraine and Belgium. 2. Nuclear industry faces two serious problems. a. Nuclear accidents b. Nuclear waste 3. Some nations have decided to phase out or stop their production of this energy source. C. Renewable energy sources 1. Flowing water, which produces hydroelectric power, is an important energy source. a. Also called hydropower b. A renewable and relatively pollution-free source of electrical energy c. Requires rivers with a steady flow, drops in elevation, and the construction of expensive dams d. Can change natural flow of rivers, causing flooding and interfering with fish migration 2. Geothermal energy, or underground heat, is another source of renewable energy. a. Originates in Earth's hot interior b. Escapes to the surface through hot springs, and steam vents 3. Solar energy involves capturing the sun's light energy and converting it into heat or electricity. 4. Wind power has been used to provide power for centuries. Petroleum, natural gas, coal, hydropower, and nuclear energy are all considered primary forms of energy. The major producers ofprimary energy are the United States, Russia, China, Saudi Arabia, and Canada. The major consumers ofprimary energy are the United States, China, Russia, Japan, and Germany. HRW material copyrighted under notice appearing earlier in this wark. 36

5 -- L..L~ a. Grinding grain, pumping water from wells with windmills, and powering sailing ships b. Aerogenerators are machines that harness wind to produce electricity. IV. POPULATIO... A...D RESOURCES (pupil Edition page 96) A. Population growth 1. Population growth rates are more important to the future of the world. 2. Control of population growth would control the standard of living for a nation's citizens. 3. Lower birthrates raise some concerns. a. Fewer young people to enter the work force b. Growing percentage of elderly people causes increased cost of health care B. Balancing population and resources 1. World population increases by more than 1 million people every five days. 2. Natural resources are not evenly distributed and people must share and use these resources wisely. 3. Many people are optimistic about the future. a. As the world's population increases, scientists will discover ways to produce new kinds of foods. b. Farmers will increase crop yield through new methods. c. More food and water will be taken from the sea. d. High-rise buildings will permit more people to live in less land space. 4. Some people question whether we have reached the point of limitation for important resources and food production. a. Will substitutes for our natural resources be found? b. Can food production keep up with population growth? c. Can we continue to pollute our planet? d. Will countries continue to trade resources? e. Will rich nations share their wealth and resources with less fortunate nations? 5. A better understanding of the world's geography will help us face these challenging issues about population and resources. The following are the birthrates/death rates per (1,000) for a selection of nations: the United States: 14.6/8.8; Brazil: 20.4/9.4; China: 16.5/6.9; Russia: 9.5/14.8; Democratic Republic of the Congo: 47.6/16.6; France: 12/