CHAPTER 36: ENVIRONMENTAL CONCERNS LECTURE OUTLINE 36.1 Human Use of Resources A resource is anything from the biotic or abiotic environment that helps meet certain basic human needs. Nonrenewable resources are limited in supply. Renewable resources are not limited in supply. A side effect of resource consumption can be pollution. Land Use Change People need a place to live. Beaches and Human Habitation At least 40% of the world population lives within 100 km of a coastline. Beach Erosion An estimated 70% of the world’s beaches are eroding. Humans carry on activities that contribute to the rising of the seas and erosion of beaches. Coastal Pollution The coast is particularly subject to pollution. Semiarid Lands and Human Habitation Desertification is the conversion of semiarid land to desertlike conditions. Tropical Rain Forests and Human Habitation Deforestation, the removal of trees, has long allowed humans to live in areas where forests once covered the land. Tropical rain forests are subject to desertification because soil in the tropics is thin and nutrient-poor. Loss of Biodiversity Development in tropical rain forests leads to loss of biodiversity. Water In some areas of the world, people do not have ready access to drinking water, and if they do, the water may be impure. Increasing Water Supplies Certain areas of the world do not have a renewable supply of water. Dams Dams catch precipitation runoff, provide water for land irrigation, and generate electricity. They are not without drawbacks, however. Aquifers To meet their freshwater needs, people are pumping vast amounts of water from underground aquifers. Environmental Consequences Removal of water is causing land subsidence and saltwater intrusion into the aquifers. Conservation of Water Reusing water and adopting conservation measures could help the world’s industries cut their water demands. Food Food comes from three activities: growing crops, raising animals, and fishing. The increase in the food supply has largely been possible because of modern farming methods, which unfortunately include some harmful practices. Soil Loss and Degradation When topsoil is lost, farmland loses its productivity. Salinization is the accumulation of mineral salts due to evaporation of excess irrigation water. Green Revolution The green revolution helped the world food supply keep pace with the rapid increase in world population but most of these plants required high levels of fertilizer, water, and pesticides. Genetic Engineering Genetic engineering can produce transgenic plants with new and different traits. Genetically engineered crops could result in still another green revolution. Domestic Livestock In more-developed countries, many people tend to have more than enough protein in their diet. Raising livestock uses up an excessive amount of fossil fuel, fertilizer, water, herbicides, and pesticides. Fishing The result of an increased number and efficiency of fishing boats was a severe reduction in fish catch. Modern fishing practices negatively impact biodiversity. Energy Modern society runs on various sources of energy. Nonrenewable Sources Most of the world’s energy comes from fossil fuels and nuclear power, both nonrenewable energy sources. Fossil Fuels and Global Climate Change The burning of fossil fuels results in an increase in greenhouse gases and global warming. Renewable Energy Sources Hydropower Hydroelectric plants convert the energy of falling water into electricity. Geothermal Energy The Earth has an internal source of heat that can be harnessed. Wind Power Wind power is expected to account for a significant percentage of our energy needs in the future. Energy and the Solar-Hydrogen Revolution We now have better ways to capture solar energy. Scientists are investigating the possibility of using solar energy to extract hydrogen from water via electrolysis. The hydrogen can then be used as a cleanburning fuel. Minerals Minerals are nonrenewable raw materials in Earth’s crust that can be mined and used by humans. Nonrenewable resources are subject to depletion. Synthetic Organic Compounds Synthetic organic compounds have a detrimental effect on the health of living things. These are produced during the production of various products humans consume. Wastes Wastes are generated during the mining and manufacturing process. These wastes can lead to pollution and human illness. Endocrine-Disrupting Contaminants Chemicals from pesticides, herbicides, plastics, food additives, and personal hygiene products can affect the endocrine system. Sewage Raw sewage causes oxygen depletion in lakes and rivers. Human feces can contain pathogenic microorganisms. Industrial Wastes Industrial wastes can include heavy metals and chlorinated hydrocarbons. These wastes enter bodies of water and are subject to biological magnification. 36.2 Impact on Biodiversity Biodiversity can be defined as the variety of life on Earth. We are presently in a biodiversity crisis—the number of extinctions expected to occur in the near future is unparalleled in Earth’s history. Habitat Loss Human occupation of the coastline, semiarid lands, tropical rain forests, and other areas are the most important cause of the loss of biodiversity. Exotic Species Exotic species are nonnative members of an ecosystem. Humans have introduced exotic species by the following means: Colonization Europeans, in particular, brought various familiar species with them when they colonized new places. Horticulture and Agriculture Some exotics now taking over vast tracts of land have escaped from cultivated areas. Accidental Transport Global trade and travel accidentally bring many new species from one country to another. Exotics on Islands Islands are particularly susceptible to environmental discord caused by the introduction of exotic species. Pollution Pollution brings about environmental changes that adversely affect the lives and health of living things. Acid Deposition Acid deposition decimates forests and lakes. Eutrophication Lakes are under stress due to overenrichment. Global Warming Global warming is expected to have many detrimental effects. Ozone Depletion The ozone shield protects Earth from harmful ultraviolet radiation. Organic Chemicals Endocrine-disrupting contaminants affect the endocrine system and reproductive potential of animals. Overexploitation Overexploitation occurs when the number of individuals taken from a wild population is so great that the population becomes severely reduced in numbers. For example, a marine ecosystem can be disrupted by over fishing. Disease Wildlife is subject to emerging diseases just as humans are. 36.3 Value of Biodiversity Biodiversity is a resource of immense value. Direct Value Various individual species perform services for human beings. Medicinal Value Most of the prescription drugs used in the United States were originally derived from living organisms. Agricultural Value Crops such as wheat, corn, and rice are derived from wild plants that have been modified. Consumptive Use Value Most freshwater and marine harvests depend on wild animals. Indirect Value These services are said to be indirect because they are pervasive and not easily discernible. Biogeochemical Cycles The biodiversity within ecosystems contributes to the workings of the various biogeochemical cycles. Waste Disposal Decomposers break down dead organic matter and other types of wastes. Provision of Fresh Water The water cycle continually supplies fresh water to terrestrial ecosystems. Forests and other natural ecosystems soak up water and then release it at a regular rate. Prevention of Soil Erosion Intact ecosystems naturally retain soil and prevent soil erosion. Regulation of Climate Globally, forests ameliorate the climate because they take up carbon dioxide and release oxygen. Ecotourism In the United States nearly 100 million people enjoy vacationing in a natural setting. 36.4 Working Toward a Sustainable Society A sustainable society would be able to provide the same goods and services for future generations of human beings as it does now and biodiversity would be conserved. Today’s Society Today’s society has several characteristics that indicate it is not sustainable. Characteristics of a Sustainable Society Natural ecosystems offer clues as to what a sustainable human society would be like, including the use of renewable solar energy and material recycling. Assessing Economic Well-Being and Quality of Life The gross national product pertains solely to economic activities and does not take into consideration any activities that are socially or environmentally harmful. Measuring Nonmonetary Values Measures that include noneconomic indicators are probably better than the GNP at revealing our quality of life. Such indices include the Index of Sustainable Economic Welfare and the Genuine Progress Indicator. Other values to consider include: Use Value The actual price we pay to use or consume a resource. Option Value Preserving options for the future. Existence Value Saving things we might not realize exist yet. Aesthetic Value Appreciating an area or creature for its beauty and/or contribution to biodiversity. Cultural Value Factors such as language, mythology, and history that are important for cultural identity. Scientific and Educational Value Valuing the knowledge of naturalists, or even an experience of nature, as types of rational facts.