Environmental science: An interdisciplinary area of study that includes both applied and theoretical aspects of human impact on the world.

Transcription

1 Chapter 1: Environmental Interrelationships THE NATURE OF ENVIRONMENTAL SCIENCE Environmental science: An interdisciplinary area of study that includes both applied and theoretical aspects of human impact on the world. The field of environmental science involves an understanding of scientific principles, economic influences, and political action. Environmental decisions often involve compromise: A decision that may be supportable from a scientific or economic point of view may not be supportable from a political point of view without modification. Often political decisions relating to the environment may not be supported by economic analysis. Environment: Everything that affects an organism during its lifetime. Science: A method for gathering and organizing information that involves observation, asking questions about observation hypothesis formation, testing hypothesis, critically evaluating the results, and publishing information so that others can evaluate the process and the conclusions. The first Earth Day: April 22, An Ecosystem Approach Ecosystem: A group of interesting species along with their physical environment. With an ecosystem there is a complex network of interacting unit. Some ecosystems have easily recognized boundaries (lakes, islands, floodplains, etc. separated by mountains). Defining an ecosystem boundary is often a matter of practical convenience. An ecosystem approach is important to dealing with environmental problems. Political and Economic Issues Environmental problems do not necessarily coincide with these artificial political boundaries. Example: air pollution may involve several local units of government, several states or provinces, and even different nations. Air pollution generated in China affects western coastal states in the United States and in British Columbia, Canada. Air pollution generated in Juarez, Mexico causes problems in the neighboring city of El Paso, TX. Lower wage rates and less strict environmental laws have influenced some U.S. industries to move to Mexico for economic advantages. The developing countries are struggling to 1

2 improve their environmental image and need the money generated by foreign investment ti improve the conditions and the environment in which their people live. The Boundary Waters Treaty established in 1909 by the International joint commission between United States and Canada to provide that the boundary waters and waters flowing across the boundary shall not be polluted on either side to the injury of health or property of the other. The Global Nature of Environmental Concerns As the human population has increased, the natural ecosystems of the Earth have been stressed. Recognition of this has led to international activities to address concerns about the Earth s natural systems and how humans are affecting them. The Earth Summit: Formally known as the United Nations Conference on Environment and Development (UNCED). One of the key outcomes was a series of policy statements on sustainable development that were identified as Agenda 21. Climate Change: Kyoto Protocol of 1997, representatives from 125 nations met in Kyoto, Japan for the Third Conference of the United Nations Framework Convention on Climate Change, resulted in commitments from the participating nations to reduce their overall emissions if six greenhouse gases (linked to global warming) by at least 5% below 1990 levels and to do so between the tear 2008 and It s one of the most important steps to date in environmental protection and international diplomacy. Greenhouse gases: carbon dioxide (CO 2 ), chlorofluorocarbons (primarily CCl 3 F and CCl 2 F 2 ), methane (CH 4 ), and nitrous oxide (N 2 O). The Millennium Ecosystem Assessment: Initiated by United Nation and completed in Four broad areas of ecosystem services were identified: (a) Supporting services: include ecosystem functions as photosynthesis, soil formation, nutrient cycling, and water cycling. (b) Provisioning services: include resources provided by ecosystems such as food, fiber, genetic resources, natural medicines, and freshwater. 2

3 (c) Regulating services: include ecosystem activities that affect air quality, water flow, erosion control, water purification, climate control, disease regulation, pest regulation, pollination, and natural hazards. (d) Cultural services: include spiritual, religious, and aesthetic values, and the use of the natural world for recreation. Regional Environmental Concerns Protecting endangered species is a concern of many parts of the world. In most metropolitan areas, the problem of endangered species is purely historical, since the construction of cities has destroyed the previously existing ecosystem. The Wilderness North: Much of Alaska and North Canada can be characterized as wilderness areas with minimal human influence. Much of this land is owned by governments, no by individuals, so government policies have a large effect on what happens in these regions. The important economic values in these regions are their trees, animals, scenery, and other natural resources. Exploitation of the region s natural resources involves significant trade-offs. The process of compromise is often difficult and does not always ensure wise decision. The Agricultural Middle: This region is dominated by intensive agriculture. This means that the original, natural ecosystems have been replaced by managed agricultural enterprise. This area was at one time wilderness. The economic value generated by this use of a rich soil resource is tremendous, and most of the land is privately owned. One of the major, nonpoint pollution sources (pollution that does not have an easily identified point of origin) is agriculture. Air pollution in the form of dust is an inevitable result of tilling the land. Soil erosion occurs when soil is exposed to wind and moving water and leads to siltation of rivers, impoundments, and lakes. 3

4 Fertilizers and other agricultural chemicals blow or washed from the areas where they applied. Nutrients washed from the land enter rivers and lakes where they encourage the growth of algae, lowering water quality. The use of pesticides causes concern about human exposure. Many farmers use groundwater for irrigation, which lowers the water table and leaves less groundwater for other purposes. The Dry West: Where rainfall is inadequate to support agriculture, ranching and raising livestock are possible. This is true in much of the drier portions of western North America. Because much of the land is of low economic value, most is still the property of government, which encourages its use by providing water for livestock and irrigation at minimal cost, offering low-cost grazing rights, and encouraging mining and their development. Many people believe that government agencies have seriously mismanaged these lands. They assert that the agencies are controlled by special interest groups and powerful politicians sensitive to the demands of ranchers, that they subsidize ranchers by charging to little for grazing rights, and that they allow destructive overgrazing because of the economic needs of ranchers. Water is an extremely valuable resource in this region. It is needed for municipal use and for agriculture. Many areas, particularly the river valleys, have fertile soils that can be used for intensive agriculture. Cash crops (cotton, fruits and vegetables) can be grown if water is available for irrigation. Because water tends to evaporate from soil rapidly, long-term use of irrigated lands often results in the buildup of salts in the soil, thus reducing fertility. Irrigation water flowing from fields is polluted by agricultural chemicals that make it unsuitable for other uses such as drinking. As cities in the region grow, an increasing conflict arises between urban dwellers who need water for drinking and other purposes, and ranchers and farmers who need the water for livestock and agriculture. As population density is low in most of this region, much of the land has a wilderness character. 4

5 An increasing conflict between the economic management of the land for livestock production and the desire on the part of many to preserve the wilderness. The Forested West The coastal areas and mountain ranges of the western United States and Canada receive sufficient rainfall for coniferous forests to dominate as vegetation. Governments and large commercial timber companies own large sections of these lands. Government forest managers historically have sold timbercutting rights at a loss and are thought by many to be too interested in the production of forest products at the expense of other, less tangible values. Environmental interests point out that it makes no sense to complain about the destruction of tropical rainforests in South America while North America makes plans to cut large areas of previously uncut, temperate rainforest. The Great Lakes and Industrial Northeast Major portions of the Great Lakes and Northeast are dominated by large metropolitan complexes that generate social and resource needs that are difficult to satisfy. Many of these older cities were formed around industrial centers that have declined, leaving behind poverty, environmental problems in abandoned industrial sites, and difficulties with solid waste disposal, air quality, and land-use priorities. One of the major resources of the region is water transport. The Great Lakes and eastern seacoast are extremely important to commerce. The waterways are maintained at considerable government expense. One of the greatest problems associated with the industrial uses of the Great Lakes and East Coast is contamination of the water with toxic materials. In some cases, unthinking or unethical individuals have dumped toxins directly into the water. In other cases, small, accidental spills or leaks over long periods of time have contaminated the sediments in harbors and bays. A major concern about these pollutants is that they bioaccumulate (see ch. 14) in the food chain. Due to the fact that so much of the North American population is concentrated in this region, the economic value of recreational use of water is extremely high. Conflicts arise between people who want to use water for industrial and shipping 5

6 purposes and those who wish to use it for recreation. As a result, open space for people is limited and urban dwellers have few opportunities to interact with the natural world. Their major environmental priorities are cleaning up contaminated sites, providing more parks and recreation facilities, reducing air and water pollution, and improving transportation. The Diverse South In many ways, the South is a microcosm of all the regions previously discussed. The petrochemical industry dominates the economies of Texas and Louisiana, and forestry and agriculture are significant elements of the economy in other parts of the region. Major metropolitan areas thrive, and much of the area is linked to the coast either directly or by the Mississippi River and its tributaries. Some areas of the South (especially Florida) have had extremely rapid population growth, which has led to groundwater problems, transportation problems, and concerns about regulating the rate of growth. Growth means money to developers and investors, but it requires municipal services, which are the responsibility of local governments. Too many people and too much development also threaten remaining natural ecosystem. Poverty has been a problem in many areas of the South. This creates a climate that encourages state and local governments to accept industrial development at the expense of other values. Often jobs are more important than the environmental consequences of the jobs; low-paying jobs are better than no jobs. The use of coastline is of major concern in many parts of the South, as coast is desirable to live, which may encourage unwise development in barrier islands and in areas that are subject to flooding during severe weather. In addition, industrial activity along the coast has resulted in the loss of wetlands. (Fig. 1.9). 6