Factors Threatening The Environment: 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. 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.

Factors Threatening The Environment: 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. 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.

Environment: Future Prospects

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.

related topics:

• Understanding the Environment
• Factors Threatening the Environment
• Efforts to Protect the Environment
  

Rain Forest

Rain Forest, woodland characterized by lush vegetation and comparatively high temperature and rainfall throughout the year. Rain forests are the world’s most biologically diverse ecosystems. Although they account for less than 7 percent of the land surface on Earth, they contain more than 50 percent—some scientists estimate as high as 90 percent—of its plant and animal species. One hectare (about 2.5 acres) of tropical rain forest may contain more than 600 species of trees.

Rain forests also play a critical role in global climate regulation by absorbing carbon dioxide, a gas believed to be partially responsible for global warming. Plants naturally absorb carbon dioxide and give off oxygen gas in the process of photosynthesis, and tropical rain forests absorb more carbon dioxide than any other terrestrial ecosystem on earth. Global emissions of carbon dioxide have increased nearly 30 percent in the last century. There is general agreement among the scientific community that by absorbing some of the gas, rain forests play a vital role in lessening its impacts.

To be classified as a rain forest, a forest must have a closed canopy, in which the treetops, or crowns, touch each other, creating a shaded forest interior. In addition, temperature and rainfall must be high and relatively even throughout the year. Forests that meet these criteria are found flanking the equator in South and Central America, Asia, Africa, and Australia. In South America, a vast, forested area of the Amazon River basin in Brazil and neighboring countries is by far the largest rain forest in the world. It encompasses more than 3.5 million sq km (about 1.4 million sq mi)—about half of the total global rain forest cover. The larger of two large rain forests in Asia is centered along the Malay Archipelago, including the islands of Borneo and Sumatra, the Malay Peninsula, and the Republic of the Philippines. The other main rain forest in Asia is found primarily on the island of New Guinea and in northern Australia. In Africa, most of the rain forest is concentrated along the Atlantic coast and the Congo River Basin.

The Greenhouse Effect

Carbon Cycle
Photosynthesis plays a crucial role in the carbon cycle. Carbon continuously circulates in the earth’s ecosystem. In the atmosphere, it exists as colorless, odorless carbon dioxide gas, which is used by plants in the process of photosynthesis. Animals acquire the carbon stored in plant tissue when they eat and exhale carbon dioxide as a by-product of metabolism. Although some carbon is removed from circulation temporarily as coal, petroleum, fossil fuels, gas, and limestone deposits, cellular respiration and photosynthesis balance to keep the amount of atmospheric carbon relatively stable. Industrialization, however, has contributed additional carbon dioxide to the environment.

The energy that lights and warms Earth comes from the Sun. Most of the energy that floods onto our planet is short-wave radiation, including visible light. When this energy strikes the surface of Earth, the energy changes from light to heat and warms Earth. Earth’s surface, in turn, releases some of this heat as long-wave infrared radiation.

Much of this long-wave infrared radiation makes it all the way back out to space, but a portion remains trapped in Earth’s atmosphere. Certain gases in the atmosphere, including water vapor, carbon dioxide, and methane, provide the trap. Absorbing and reflecting infrared waves radiated by Earth, these gases conserve heat as the glass in a greenhouse does and are thus known as greenhouse gases. As the concentration of these greenhouse gases in the atmosphere increases, more heat energy remains trapped below. All life on Earth relies on this greenhouse effect—without it, the planet would be colder by about 33 Celsius degrees (59 Fahrenheit degrees), and ice would cover Earth from pole to pole. However, a growing excess of greenhouse gases in Earth’s atmosphere threatens to tip the balance in the other direction—toward continual warming.

Types of Greenhouse Gases

Greenhouse gases occur naturally in the environment and also result from human activities. By far the most abundant greenhouse gas is water vapor, which reaches the atmosphere through evaporation from oceans, lakes, and rivers.

Carbon dioxide is the next most abundant greenhouse gas. It flows into the atmosphere from many natural processes, such as volcanic eruptions; the respiration of animals, which breathe in oxygen and exhale carbon dioxide; and the burning or decay of organic matter, such as plants. Carbon dioxide leaves the atmosphere when it is absorbed into ocean water and through the photosynthesis of plants, especially trees. Photosynthesis breaks up carbon dioxide, releasing oxygen into the atmosphere and incorporating the carbon into new plant tissue.

Humans escalate the amount of carbon dioxide released to the atmosphere when they burn fossil fuels, solid wastes, and wood and wood products to heat buildings, drive vehicles, and generate electricity. At the same time, the number of trees available to absorb carbon dioxide through photosynthesis has been greatly reduced by deforestation, the long-term destruction of forests by indiscriminate cutting of trees for lumber or to clear land for agricultural activities.

Ultimately, the oceans and other natural processes absorb excess carbon dioxide in the atmosphere. However, human activities have caused carbon dioxide to be released to the atmosphere at rates much faster than that at which Earth’s natural processes can cycle this gas.

Methane is an even more effective insulator, trapping over 20 times more heat than does the same amount of carbon dioxide. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane also comes from rotting organic waste in landfills, and it is released from certain animals, especially cows, as a byproduct of digestion.

Nitrous oxide is a powerful insulating gas released primarily by burning fossil fuels and by plowing farm soils. Nitrous oxide traps about 300 times more heat than does the same amount of carbon dioxide. The concentration of nitrous oxide in the atmosphere has increased 17 percent over preindustrial levels.

In addition, greenhouse gases are produced in many manufacturing processes. Perfluorinated compounds result from the smelting of aluminum. Hydrofluorocarbons form during the manufacture of many products, including the foams used in insulation, furniture, and car seats. Refrigerators built in some developing nations still use chlorofluorocarbons as coolants. In addition to their ability to retain atmospheric heat, some of these synthetic chemicals also destroy Earth’s high-altitude ozone layer, the protective layer of gases that shields Earth from damaging ultraviolet radiation. For most of the 20th century these chemicals have been accumulating in the atmosphere at unprecedented rates.

Measuring Global Warming

GOES Weather Satellite
Broadcasters use data from meteorological satellites to predict weather and to broadcast storm warnings when necessary. Satellites such as the Geostationary Operational Environmental Satellite (GOES) collect meteorological and infrared information about the atmosphere and the ocean. A camera on the GOES is continuously pointed at Earth, broadcasting satellite images of cloud patterns both day and night. Here, the GOES-C satellite is being encapsulated inside its payload fairing aboard a Delta rocket.

As early as 1896 scientists suggested that burning fossil fuels might change the composition of the atmosphere and that an increase in global average temperature might result. The first part of this hypothesis was confirmed in 1957, when researchers working in the global research program called the International Geophysical Year sampled the atmosphere from the top of the Hawaiian volcano Mauna Loa. Their instruments indicated that carbon dioxide concentration was indeed rising. Since then, the composition of the atmosphere has been carefully tracked. The data collected show undeniably that the concentrations of greenhouse gases in the atmosphere are increasing.

Scientists have long suspected that the global climate, the long-term average pattern of temperature, was also growing warmer, but they were unable to provide conclusive proof. Temperatures vary widely all the time and from place to place. It takes many years of climate observations to establish a trend. Records going back to the late 1800s did seem to show a warming trend, but these statistics were spotty and untrustworthy. Early weather stations often were located near cities, where temperature measurements were affected by the heat emitted from buildings and vehicles and stored by building materials and pavements. Since 1957, however, data have been gathered from more reliable weather stations, located far away from cities, and from satellites. These data have provided new, more accurate measurements, especially for the 70 percent of the planetary surface that is ocean water. These more accurate records indicate that a surface warming trend exists and that, moreover, it has become more pronounced. Looking back from the end of the 20th century, records show that the ten warmest years of the century all occurred after 1980, and the three hottest years occurred after 1990, with 1998 being the warmest year of all.

Greenhouse gas concentrations are increasing. Temperatures are rising. But does the gas increase necessarily cause the warming, and will these two phenomena continue to occur together? In 1988 the United Nations Environment Program and the World Meteorological Organization established a panel of 200 leading scientists to consider the evidence. In its Third Assessment Report, released in 2001, this Intergovernmental Panel on Climate Change (IPCC) concluded that global air temperature had increased 0.6 Celsius degree (1 Fahrenheit degree) since 1861. The panel agreed that the warming was caused primarily by human activities that add greenhouse gases to the atmosphere. The IPCC predicted in 2001 that the average global temperature would rise by another 1.4 to 5.8 Celsius degrees (2.5 to 10.4 Fahrenheit degrees) by the year 2100.

The IPCC panel cautioned that even if greenhouse gas concentrations in the atmosphere ceased growing by the year 2100, the climate would continue to warm for a period after that as a result of past emissions. Carbon dioxide remains in the atmosphere for a century or more before nature can dispose of it. If greenhouse gas emissions continue to increase, experts predict that carbon dioxide concentrations in the atmosphere could rise to more than three times preindustrial levels early in the 22nd century, resulting in dramatic climate changes. Large climate changes of the type predicted are not unprecedented; indeed, they have occurred many times in the history of Earth. However, human beings would face this latest climate swing with a huge population at risk.