Bonus Anda

Rabu, 05 Mei 2010


Environment, all of the external factors affecting an organism. These factors may be other living organisms (biotic factors) or nonliving variables (abiotic factors), such as temperature, rainfall, day length, wind, and ocean currents. The interactions of organisms with biotic and abiotic factors form an ecosystem. Even minute changes in any one factor in an ecosystem can influence whether or not a particular plant or animal species will be successful in its environment.
Organisms and their environment constantly interact, and both are changed by this interaction. Like all other living creatures, humans have clearly changed their environment, but they have done so generally on a grander scale than have all other species. Some of these human-induced changes—such as the destruction of the world’s tropical rain forests to create farms or grazing land for cattle—have led to altered climate patterns (see Global Warming). In turn, altered climate patterns have changed the way animals and plants are distributed in different ecosystems.

Scientists study the long-term consequences of human actions on the environment, while environmentalists—professionals in various fields, as well as concerned citizens—advocate ways to lessen the impact of human activity on the natural world.
Environment, all of the external factors affecting an organism. These factors may be other living organisms (biotic factors) or nonliving variables (abiotic factors), such as temperature, rainfall, day length, wind, and ocean currents. The interactions of organisms with biotic and abiotic factors form an ecosystem. Even minute changes in any one factor in an ecosystem can influence whether or not a particular plant or animal species will be successful in its environment.
Organisms and their environment constantly interact, and both are changed by this interaction. Like all other living creatures, humans have clearly changed their environment, but they have done so generally on a grander scale than have all other species. Some of these human-induced changes—such as the destruction of the world’s tropical rain forests to create farms or grazing land for cattle—have led to altered climate patterns (see Global Warming). In turn, altered climate patterns have changed the way animals and plants are distributed in different ecosystems.
Scientists study the long-term consequences of human actions on the environment, while environmentalists—professionals in various fields, as well as concerned citizens—advocate ways to lessen the impact of human activity on the natural world.
The science of ecology attempts to explain why plants and animals live where they do and why their populations are the sizes they are. Understanding the distribution and population size of organisms helps scientists evaluate the health of the environment.
In 1840 German chemist Justus von Liebig first proposed that populations cannot grow indefinitely, a basic principle now known as the Law of the Minimum. Biotic and abiotic factors, singly or in combination, ultimately limit the size that any population may attain. This size limit, known as a population’s carrying capacity, occurs when needed resources, such as food, breeding sites, and water, are in short supply. For example, the amount of nutrients in soil influences the amount of wheat that grows on a farm. If just one soil nutrient, such as nitrogen, is missing or below optimal levels, fewer healthy wheat plants will grow.
Population size and distribution may also be affected, either directly or indirectly, by the way species in an ecosystem interact with one another. In an experiment performed in the late 1960s in the rocky tidal zone along the Pacific Coast of the United States, American ecologist Robert Paine studied an area that contained 15 species of invertebrates, including starfish, mussels, limpets, barnacles, and chitons. Paine found that in this ecosystem one species of starfish preyed heavily on a species of mussel, preventing that mussel population from multiplying and monopolizing space in the tidal zone. When Paine removed the starfish from the area, he found that the mussel population quickly increased in size, crowding out most other organisms from rock surfaces. The number of invertebrate species in the ecosystem soon dropped to eight species. Paine concluded that the loss of just one species, the starfish, indirectly led to the loss of an additional six species and a transformation of the ecosystem.
Typically, the species that coexist in ecosystems have evolved together for many generations. These populations have established balanced interactions with each other that enable all populations in the area to remain relatively stable. Occasionally, however, natural or human-made disruptions occur that have unforeseen consequences to populations in an ecosystem. For example, 17th-century sailors routinely introduced goats to isolated oceanic islands, intending for the goats to roam freely and serve as a source of meat when the sailors returned to the islands during future voyages. As nonnative species free from all natural predators, the goats thrived and, in the process, overgrazed many of the islands. With a change in plant composition, many of the native animal species on the islands were driven to extinction. A simple action, the introduction of goats to an island, yielded many changes in the island ecosystem, demonstrating that all members of a community are closely interconnected.
To better understand the impact of natural and human disruptions on the Earth, in 1991 the National Aeronautics and Space Administration (NASA) began to use artificial satellites to study global change. NASA’s undertaking, called Earth Science Enterprise, is part of an international effort linking numerous satellites into a single Earth Observing System (EOS). EOS collects information about the interactions occurring in the atmosphere, on land, and in the oceans, and these data help scientists and lawmakers make sound environmental policy decisions.
The problems facing the environment are vast and diverse. Global warming, the depletion of the ozone layer in the atmosphere, and destruction of the world’s rain forests are just some of the problems that many scientists believe will reach critical proportions in the coming decades. All of these problems will be directly affected by the size of the human population.
A Population Growth
Human population growth is at the root of virtually all of the world’s environmental problems. Although the growth rate of the world’s population has slowed slightly since the 1990s, the world’s population increases by about 77 million human beings each year. As the number of people increases, crowding generates pollution, destroys more habitats, and uses up additional natural resources.
The Population Division of the United Nations (UN) predicts that the world’s population will increase from 6.23 billion people in 2000 to 9.3 billion people in 2050. The UN estimates that the population will stabilize at more than 11 billion in 2200. Other experts predict that numbers will continue to rise into the foreseeable future, to as many as 19 billion people by the year 2200.
Although rates of population increase are now much slower in the developed world than in the developing world, it would be a mistake to assume that population growth is primarily a problem of developing countries. In fact, because larger amounts of resources per person are used in developed nations, each individual from the developed world has a much greater environmental impact than does a person from a developing country. Conservation strategies that would not significantly alter lifestyles but that would greatly lessen environmental impact are essential in the developed world.
In the developing world, meanwhile, the most important factors necessary to lower population growth rates are democracy and social justice. Studies show that population growth rates have fallen in developing areas where several social conditions exist. In these areas, literacy rates have increased and women receive economic status equal to that of men, enabling women to hold jobs and own property. In addition, birth control information in these areas is more widely available, and women are free to make their own reproductive decisions.
B Global Warming
Like the glass panes in a greenhouse, certain gases in the Earth’s atmosphere permit the Sun’s radiation to heat Earth. At the same time, these gases retard the escape into space of the infrared energy radiated back out by Earth. This process is referred to as the greenhouse effect. These gases, primarily carbon dioxide, methane, nitrous oxide, and water vapor, insulate Earth’s surface, helping to maintain warm temperatures. Without these gases, Earth would be a frozen planet with an average temperature of about -18°C (about 0°F) instead of a comfortable 15°C (59°F). If the concentration of these gases rises, they trap more heat within the atmosphere, causing worldwide temperatures to rise.
Within the last century, the amount of carbon dioxide in the atmosphere has increased dramatically, largely because people burn vast amounts of fossil fuels—coal and petroleum and its derivatives. Average global temperature also has increased—by about 0.6 Celsius degree (1 Fahrenheit degree) within the past century. Atmospheric scientists have found that at least half of that temperature increase can be attributed to human activity. They predict that unless dramatic action is taken, global temperature will continue to rise by 1.4 to 5.8 Celsius degrees (2.5 to 10.4 Fahrenheit degrees) over the next century. Although such an increase may not seem like a great difference, during the last ice age the global temperature was only 2.2 Celsius degrees (4 Fahrenheit degrees) cooler than it is presently.
The consequences of such a modest increase in temperature may be devastating. Already scientists have detected a 40 percent reduction in the average thickness of Arctic ice. Other problems that may develop include a rise in sea levels that will completely inundate a number of low-lying island nations and flood many coastal cities, such as New York and Miami. Many plant and animal species will probably be driven into extinction, agriculture will be severely disrupted in many regions, and the frequency of severe hurricanes and droughts will likely increase.
C Depletion of the Ozone Layer
The ozone layer, a thin band in the stratosphere (layer of the upper atmosphere), serves to shield Earth from the Sun’s harmful ultraviolet rays. In the 1970s, scientists discovered that chlorofluorocarbons (CFCs)—chemicals used in refrigeration, air-conditioning systems, cleaning solvents, and aerosol sprays—destroy the ozone layer. CFCs release chlorine into the atmosphere; chlorine, in turn, breaks down ozone molecules. Because chlorine is not affected by its interaction with ozone, each chlorine molecule has the ability to destroy a large amount of ozone for an extended period of time.
The consequences of continued depletion of the ozone layer would be dramatic. Increased ultraviolet radiation would lead to a growing number of skin cancers and cataracts and also reduce the ability of immune systems to respond to infection. Additionally, growth of the world’s oceanic plankton, the base of most marine food chains, would decline. Plankton contains photosynthetic organisms that break down carbon dioxide. If plankton populations decline, it may lead to increased carbon dioxide levels in the atmosphere and thus to global warming. Recent studies suggest that global warming, in turn, may increase the amount of ozone destroyed. Even if the manufacture of CFCs is immediately banned, the chlorine already released into the atmosphere will continue to destroy the ozone layer for many decades.
In 1987 an international pact called the Montréal Protocol on Substances that Deplete the Ozone Layer set specific targets for all nations to achieve in order to reduce emissions of chemicals responsible for the destruction of the ozone layer. Many people had hoped that this treaty would cause ozone loss to peak and begin to decline by the year 2000. In fact, in the fall of 2000, the hole in the ozone layer over Antarctica was the largest ever recorded. The hole the following year was slightly smaller, leading some to believe that the depletion of ozone had stabilized. Even if the most stringent prohibitions against CFCs are implemented, however, scientists expect that it will take at least 50 more years for the hole over Antarctica to close completely.
D Habitat Destruction and Species Extinction
Plant and animal species are dying out at an unprecedented rate (see Endangered Species). Estimates range that from 4,000 to as many as 50,000 species per year become extinct. The leading cause of extinction is habitat destruction, particularly of the world’s richest ecosystems—tropical rain forests and coral reefs. If the world’s rain forests continue to be cut down at the current rate, they may completely disappear by the year 2030. In addition, if the world’s population continues to grow at its present rate and puts even more pressure on these habitats, they might well be destroyed sooner.
E Air Pollution
A significant portion of industry and transportation burns fossil fuels, such as gasoline. When these fuels burn, chemicals and particulate matter are released into the atmosphere. Although a vast number of substances contribute to air pollution, the most common air pollutants contain carbon, sulfur, and nitrogen. These chemicals interact with one another and with ultraviolet radiation in sunlight in dangerous ways. Smog, usually found in urban areas with large numbers of automobiles, forms when nitrogen oxides react with hydrocarbons in the air to produce aldehydes and ketones. Smog can cause serious health problems.
Acid rain forms when sulfur dioxide and nitrous oxide transform into sulfuric acid and nitric acid in the atmosphere and come back to Earth in precipitation. Acid rain has made numerous lakes so acidic that they no longer support fish populations. Acid rain is also responsible for the decline of many forest ecosystems worldwide, including Germany’s Black Forest and forests throughout the eastern United States.
F Water Pollution
Estimates suggest that nearly 1.5 billion people worldwide lack safe drinking water and that at least 5 million deaths per year can be attributed to waterborne diseases. Water pollution may come from point sources or nonpoint sources. Point sources discharge pollutants from specific locations, such as factories, sewage treatment plants, and oil tankers. The technology exists to monitor and regulate point sources of pollution, although in some areas this occurs only sporadically. Pollution from nonpoint sources occurs when rainfall or snowmelt moves over and through the ground. As the runoff moves, it picks up and carries away pollutants, such as pesticides and fertilizers, depositing the pollutants into lakes, rivers, wetlands, coastal waters, and even underground sources of drinking water. Pollution arising from nonpoint sources accounts for a majority of the contaminants in streams and lakes.
With almost 80 percent of the planet covered by oceans, people have long acted as if those bodies of water could serve as a limitless dumping ground for wastes. However, raw sewage, garbage, and oil spills have begun to overwhelm the diluting capabilities of the oceans, and most coastal waters are now polluted, threatening marine wildlife. Beaches around the world close regularly, often because the surrounding waters contain high levels of bacteria from sewage disposal.
G Groundwater Depletion and Contamination
Water that collects beneath the ground is called groundwater. Worldwide, groundwater is 40 times more abundant than fresh water in streams and lakes. In the United States, approximately half the drinking water comes from groundwater. Although groundwater is a renewable resource, reserves replenish relatively slowly. Presently, groundwater in the United States is withdrawn approximately four times faster than it is naturally replaced. The Ogallala Aquifer, a huge underground reservoir stretching under eight states of the Great Plains, is drawn down at rates exceeding 100 times the replacement rate. Agricultural practices depending on this source of water need to change within a generation in order to save this groundwater source.
In addition to groundwater depletion, scientists worry about groundwater contamination, which arises from leaking underground storage tanks, poorly designed industrial waste ponds, and seepage from the deep-well injection of hazardous wastes into underground geologic formations. By some estimates, on average, 25 percent of usable groundwater is contaminated, and in some areas as much as 75 percent is contaminated.
H Chemical Risks
A number of toxic substances that humans encounter regularly may pose serious health risks. Pesticide residues on vegetable crops, mercury in fish, and many industrially produced chemicals may cause cancer, birth defects, genetic mutations, or death. Many chemicals have been found to mimic estrogen, the hormone that controls the development of the female reproductive system in a large number of animal species. Preliminary results indicate that these chemicals, in trace amounts, may disrupt development and lead to a host of serious problems in both males and females, including infertility, increased mortality of offspring, and behavioral changes such as increased aggression.
I Environmental Racism
Studies have shown that not all individuals are equally exposed to pollution. For example, worldwide toxic-waste sites are more prevalent in poorer communities. In the United States the single most important factor in predicting the location of hazardous-waste sites is the ethnic composition of a neighborhood. Three of the five largest commercial hazardous-waste landfills in America are in predominantly black or Hispanic neighborhoods, and three out of every five black or Hispanic Americans live in the vicinity of an uncontrolled toxic-waste site. The wealth of a community is not nearly as good a predictor of hazardous-waste locations as the ethnic background of the residents, suggesting that the selection of sites for hazardous-waste disposal involves racism.
Environmental racism takes international forms as well. American corporations often continue to produce dangerous, U.S.-banned chemicals and ship them to developing countries. Additionally, the developed world has shipped large amounts of toxic waste to developing countries for less-than-safe disposal. For instance, experts estimate that 50 to 80 percent of electronic waste produced in the United States, including computer parts, is shipped to waste sites in developing countries, such as China and India. At a waste site in Giuyu, China, laborers with no protective clothing regularly burn plastics and circuit boards from old computers. They pour acid on electronic parts to extract silver and gold, and they smash cathode-ray tubes from computer monitors to remove lead. These activities so pollute the groundwater beneath the site that drinking water is trucked in to the area from a town 29 km (18 mi) away.
J Energy Production
The limited supply of fossil fuels, coupled with their contributions to global warming, air pollution, and acid rain, makes it clear that alternative forms of energy will be needed to fuel industrial production and transportation. A number of energy alternatives are available, but many of these options are unlikely to replace fossil fuels in the foreseeable future because they cost more, produce less energy than fossil fuels, or pose safety risks.
A handful of countries produce a portion of their electricity using nuclear energy. But many people oppose nuclear energy because an accident can cause massive devastation. The 1986 accident at the Chernobyl’ nuclear power plant in the Ukraine scattered radioactive contamination over a large part of Europe (see Chernobyl’ Accident). Approximately 200,000 people were evacuated, and human health has been dramatically affected. Studies in 1999 found that the rate of thyroid cancer in young Ukrainian children was ten times higher than was the norm prior to the accident.
One reasonable solution combines conservation strategies with the increased use of solar energy. The price of solar energy relative to traditional fuels has steadily dropped, and if environmental concerns were factored into the cost, solar power would already be significantly cheaper.
Most scientists agree that if pollution and other environmental deterrents continue at their present rates, the result will be irreversible damage to the ecological cycles and balances in nature upon which all life depends. Scientists warn that fundamental, and perhaps drastic, changes in human behavior will be required to avert an ecological crisis.
To safeguard the healthful environment that is essential to life, humans must learn that Earth does not have infinite resources. Earth’s limited resources must be conserved and, where possible, reused. Furthermore, humans must devise new strategies that mesh environmental progress with economic growth. The future growth of developing nations depends upon the development of sustainable conservation methods that protect the environment while also meeting the basic needs of citizens.
Many nations have acted to control or reduce environmental problems. For example, Great Britain has largely succeeded in cleaning up the waters of the Thames and other rivers, and London no longer suffers the heavy smogs caused by industrial pollutants. Japan has some of the world’s strictest standards for the control of water and air pollution. In Canada, the Department of Commerce has developed comprehensive programs covering environmental contaminants.
In the United States, the Environmental Protection Agency (EPA) was established in 1970 to protect the nation’s natural resources. In addition, the U.S. Congress has provided governmental agencies with legislation designed to protect the environment. Many U.S. states have also established environmental protection agencies. Citizen groups, such as the Sierra Club and the National Audubon Society, educate the public, support environment-friendly legislation, and help assure that federal and state laws are enforced by pointing out violations.
A Environmentalism in the United States
In the United States the modern environmental movement is rooted in a 19th-century New England philosophical movement called transcendentalism, whose leaders included the poet and essayist Ralph Waldo Emerson and the naturalist and author Henry David Thoreau. In their writings, both men expressed a reverence for the natural world, believing that humans and nature shared a divine spirit. Emerson asserted that nature was eternal and capable of recovering from mistreatment at the hands of humans. Thoreau, more protective and pessimistic, has been quoted as saying, “Thank God, men cannot yet fly and lay waste the sky as well as the earth.”
Although Emerson and Thoreau wrote eloquently about the value of nature and its spiritual importance to humans, neither of them undertook a systematic analysis of the effects that humans have on their environment. That task was left for 19th-century American diplomat George Perkins Marsh. In 1864 Marsh published Man and Nature; or, Physical Geography as Modified by Human Action, considered the first book to demonstrate that human activity could cause dramatic and irreversible damage to Earth. Marsh explained how some agricultural practices had led to deforestation, loss of wetlands, desertification (the process of land becoming desert), species extinction, and changes in weather patterns.
In the early 20th century, U.S. president Theodore Roosevelt greatly expanded both the national forest and national park systems and created a system of national wildlife refuges. Roosevelt appointed forestry expert Gifford Pinchot as head of the U.S. Forest Service, and together they molded the foundation of the American conservation movement, developing methods for the sustainable use and protection of natural resources. Roosevelt and Pinchot recognized that even the vast natural resources of the United States were not limitless and thus had to be managed carefully, and they believed that those resources should be used for the betterment of the American people. Roosevelt, thinking broadly about resources, claimed that one of the most valuable natural assets was the American people themselves, and he argued that the protection of human health was a central and valid focus for the conservation movement.
Roosevelt also was a friend of Scottish American naturalist and essayist John Muir, founder of the Sierra Club. Muir’s philosophical approach to the environment was very different from Pinchot’s: Muir valued nature for its own sake and argued forcefully to protect species and preserve wilderness, whereas Pinchot was much more concerned with the use of natural resources to serve human needs. Their perspectives fully diverged in the debate over California’s Hetch Hetchy Valley, often considered a twin to the Yosemite Valley, also in California. Pinchot wanted to dam the Tuolumne River and flood the valley to provide water and electricity to San Francisco, while Muir thought the destruction of such a natural wonder an abomination. Eventually Pinchot’s view won and the dam was authorized in 1913.
When Franklin D. Roosevelt assumed the U.S. presidency in 1933, he continued and expanded on the conservation efforts begun earlier in the century during the administration of Theodore Roosevelt. Franklin Roosevelt expanded national parks and national forests. During the 1930s, he faced the twin challenges of massive unemployment in the Great Depression and environmental havoc wreaked by the Dust Bowl conditions in the Midwest. In response, Roosevelt created the Civilian Conservation Corps to replant forests and improve recreational opportunities on public land and the Soil Conservation Service to protect valuable topsoil.
In 1962 in her book Silent Spring, American biologist Rachel Carson warned of the grave dangers posed by the indiscriminate use of dichlorodiphenyltrichloroethane (DDT) and related pesticides. The book’s title suggested a time when birds, their populations greatly reduced by pesticides, could no longer be heard singing in the spring. Carson, by arguing that humans as well as wildlife were at risk, issued a call to action. Silent Spring combined solid science, a reverence for nature as strong as that of the transcendentalists, and a wonderfully poetic style that moved people to a new level of environmental awareness and activism.
By the late 1960s environmental awareness had become much more commonplace. Numerous grassroots environmental organizations were established to work for political change, including the Environmental Defense Fund in 1967 (now known as Environmental Defense), Friends of the Earth in 1968, the Natural Resources Defense Council in 1970, and the Sierra Club Legal Defense Fund in 1971. On April 22, 1970, the first Earth Day, approximately 20 million Americans gathered at various sites across the country to protest corporate and governmental abuse of the environment.
B U.S. Legislation
The strong environmental sentiments that led to Earth Day yielded dramatic changes in American legislation and reflected an expanded set of priorities. In 1964 the Congress of the United States passed the Wilderness Act in an attempt to set aside, in the words of the act, “an area where Earth and its community of life are untrammeled by man”; the lands designated as wilderness areas were to be “affected primarily by nature.” In 1968 Congress adopted the Wild and Scenic Rivers Act to ensure that at least some of the scenic and recreational value of the country’s rivers was preserved in the face of a growing number of dams and riverside development.
In 1970 the United States government established the Environmental Protection Agency (EPA), and attention began to shift toward pollution control and the establishment of national environmental quality standards. The EPA is responsible for the environmental well-being of the country as defined through numerous specific pieces of legislation. One of these, the Clean Air Act of 1970, became the model for future measures. The act established national air-quality standards, gave states the responsibility for developing and enforcing plans to use these standards, and set up compliance schedules. Additionally, the act made federal funding available to states to assist in their efforts. The National Environmental Protection Act (NEPA), also enacted in 1970, required an environmental assessment of all federally funded projects.
The Occupational Safety and Health Administration (OSHA) was formed in 1971, although it was placed under the control of the Department of Labor rather than the EPA. Reflecting Theodore Roosevelt’s belief that human health was a natural resource worthy of protection, OSHA’s mission was “to assure so far as possible every working man and woman in the Nation safe and healthful working conditions.”
In 1972 Congress passed the Clean Water Act, designed to do for the nation’s water supply what the Clean Air Act accomplished for the atmosphere. The Endangered Species Act was passed the following year and has been described by the Supreme Court of the United States as “the most comprehensive legislation for the preservation of endangered species ever enacted by any nation.” The U.S. Fish and Wildlife Service, which enforces the Endangered Species Act, lists over 1,200 plants and animals in the United States in danger of extinction. Organisms listed as endangered receive federal protection and funding to establish conservation programs. As a result of this act, the populations of some endangered species, such as the American alligator and Robbins’ cinquefoil (a rare plant found in the White Mountains of New Hampshire), have recovered and have been removed from the endangered list. Others species, including the dusky seaside sparrow and the Maryland darter, received aid too late and these animals have become extinct.
The Resource Conservation and Recovery Act (RCRA) was adopted in 1976 with the twin goals of protecting human health and the environment and conserving valuable natural resources. Through this act, the federal government took a more active role in controlling solid and hazardous waste, as well as in promoting recycling. Despite the good intentions of RCRA, numerous hazardous-waste sites were created throughout the country. To combat the dangers posed by these sites, Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980. Known as Superfund, the act created a $15-billion fund of public money, to be increased by taxes paid by polluting industries. Despite its large funding, Superfund remains inadequate to deal with the thousands of hazardous sites in need of cleanup. The vast majority of these sites occur on federal military reservations. Of the more than 43,000 sites screened since the passage of CERCLA in 1980, the EPA has earmarked 1,200 sites for remediation. Of these, cleanup has been completed on fewer than 800.
C U.S. Politics and Environmental Regulation
In the United States, federal environmental legislation often faces heated debates between Republicans, who believe industry and development are being unnecessarily stifled, and Democrats who contend that the environment is being irreparably damaged. For example, environmental legislation came under attack during the conservative Republican presidencies of Ronald Reagan and George H. W. Bush in the 1980s and early 1990s. During this time, as each piece of environmental legislation was modified or came before Congress for reauthorization, battles developed between Republicans and Democrats. Conservatives in Congress successfully argued that too much public money was being spent on the environment and that the federal government should play a much-reduced role in environmental regulation.
The federal government took a more active role in protecting the environment during the presidency of Democrat Bill Clinton (1993-2001). During Clinton’s administration, the United States participated in the development of international agreements targeting global warming, logging and mining were prohibited in areas that had no roads, and the United States and Canada signed an agreement to clean up toxic substances in the Great Lakes. Clinton also protected more federal lands from development than any president since Theodore Roosevelt.
President George W. Bush, elected in 2001, advocated that government should be less involved in environmental protection and that environmental restrictions that stymie business are bad for the economy. To ease environmental restrictions placed on industries, Bush relaxed air quality and fuel efficiency standards, and he took steps to open roadless areas to logging and mining. The Bush energy policy promoted the construction of new power plants while encouraging oil exploration, often in environmentally sensitive areas.
Early in his administration, Bush declined to endorse the Kyōto Protocol, an international agreement that limits emissions of heat-trapping gases. Bush argued that the emissions reductions called for by the Kyōto Protocol are unfair because they do not affect nations, especially China and India, that are also major producers of gas emissions. Bush also argued that the emissions reductions would be too costly and would adversely affect the U.S. economy.
D Global Efforts
During the late 1960s and early 1970s nations began to work together to develop worldwide approaches for monitoring and restricting global pollution. The first major international conference on environmental issues was held in Stockholm, Sweden, in 1972 and was sponsored by the United Nations. This meeting, at which the United States took a leading role, was controversial because many developing countries were fearful that a focus on environmental protection was a means for the developed world to keep the undeveloped world in an economically subservient position. The most important outcome of the conference was the creation of the United Nations Environmental Program (UNEP).
UNEP was designed to be “the environmental conscience of the United Nations,” and, in an attempt to allay fears of the developing world, it became the first UN agency to be headquartered in a developing country, with offices in Nairobi, Kenya. In addition to attempting to achieve scientific consensus about major environmental issues, a major focus for UNEP has been the study of ways to encourage sustainable development—increasing standards of living without destroying the environment.
D1 International Treaties
Dozens of international agreements have been reached in recent decades in an effort to improve the world’s environmental status. In 1975 the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) went into effect to reduce commerce in animals and plants on the edge of extinction. In 1982 the International Whaling Commission agreed to a moratorium on all commercial whaling. Perhaps the most important international agreement was the 1987 Montréal Protocol on Substances that Deplete the Ozone Layer. For the first time, an international pact set specific targets for reducing emissions of chemicals responsible for the destruction of Earth’s ozone layer. The international community again came together in 1989 to form the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, a treaty that limits the movement of hazardous wastes between countries.
In 1992 the UN Conference on Environment and Development was held in Rio de Janeiro, Brazil. Popularly known as the Earth Summit, this meeting was the largest gathering of world leaders in history. The conference produced two major treaties. The first was an agreement for nations to voluntarily reduce emission of gases leading to global warming, and the second was a pact on biodiversity requiring countries to develop plans to protect endangered species and habitats. At the insistence of the United States, however, the final version of the global warming treaty was dramatically scaled back. The United States was also one of the very few countries that refused to sign the biodiversity treaty. United States representatives objected to a part of the treaty that specified that money to come from the use of natural resources from protected ecosystems, such as rain forests, should be shared equally between the source country and the corporation or institution removing the materials.
The 1992 agreement on global warming limited each industrialized nation to emissions in the year 2000 that were equal to or below 1990 emissions. However, these limits were voluntary and with no enforcement provisions included in the agreement it became clear by 1997 that these goals would never be met. At a follow-up conference in Kyōto, Japan, representatives from 160 countries signed the Kyōto Protocol. This agreement called for industrialized nations to reduce emissions to an average of about 5 percent below 1990 emission levels and to reach this goal between the years 2008 and 2012. For this accord to become international law, however, it had to be ratified by at least 55 countries. The United States has refused to ratify the accord, but Japan and the 15 countries that make up the European Union have ratified it. Even if the Kyōto Protocol does become international law, however, scientists expect that its emission requirements are too minimal to be effective. Some experts predict that a 60 percent reduction in emissions will be necessary to stabilize the world’s climate.
In 2002 delegates from nearly 200 countries convened at the World Summit on Sustainable Development in Johannesburg, South Africa, to establish new sustainable development goals for the 21st century. They also negotiated to strengthen commitments from the governments of developed nations to provide aid for sustainable development. Among the outcomes, the 2002 summit created an action plan that called on nations to reduce by half the proportion of people who lack sanitation by 2015, to minimize health and environmental problems caused by chemical pollution by 2020, and to reduce significantly the number of endangered species by 2010.
D2 Green Parties
A desire for environmental change led to the creation of various political parties around the world whose emphasis was largely on environmental protection. The first of these organizations, collectively known as green parties, was the Values Party in New Zealand, created in 1972. In 1993, 23 green parties from eastern and western Europe came together to form the European Federation of Green Parties. They hoped that together they would have the leverage necessary to demand that environmental issues such as pollution control, population growth, and sustainable development be more fully addressed by various national governments and international bodies.
By far the most successful green party has been Bündnis 90/Die Grünen, the green party of Germany. In 1998 Bündnis 90/Die Grünen formed a coalition with the newly elected Social Democratic Party of German chancellor Gerhard Schröder, marking the first time that the green party had entered Germany’s national government.
Green parties have developed in almost all countries that have open elections, but they have had the largest impact in those nations where proportional representation within a parliamentary system occurs. Thus, the green parties have not played a significant role in American politics. However, some experts believe that in the disputed presidential election of 2000, the votes received by Green Party candidate Ralph Nader split the vote so that George W. Bush was able to win enough electoral votes to capture the presidency.
Global environmental collapse is not inevitable. But the developed world must work with the developing world to ensure that new industrialized economies do not add to the world’s environmental problems. Politicians must think of sustainable development rather than economic expansion. Conservation strategies have to become more widely accepted, and people must learn that energy use can be dramatically diminished without sacrificing comfort. In short, with the technology that currently exists, the years of global environmental mistreatment can begin to be reversed.

Contributed By:
Michael Zimmerman
Microsoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.

2 komentar:

  1. Assalamu'alaikum Wr.Wb.
    Numpang lewat
    Salam kenal pak guru, semoga berkenan.
    Wassalamu'alaikum Wr.Wb

  2. Wa'alaikum salam Wr. Wb.
    Terima kasih.
    mari kita bertukar ilmu dan pengalaman untuk kemajuan bangsa


Bromo Caldera, East Java, Indonesia