Humans are bringing about another global-scale change in the atmosphere: the increase in what are called greenhouse gases otherwise known as global warming. Like glass in a greenhouse, these gases admit the Sun’s light but tend to reflect back downward the heat that … Continue reading
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Living with the Monster Near the end of a half-mile-long hallway connecting the four reactors of the Chornobyl Nuclear Power Plant, graph bars and squiggles flash on a monitor. Only a few yards away rises the concrete-and-steel sarcophagus sheathing the … Continue reading
This article discusses the effects of El Niño, a serious dislocation of the world’s weather system that occurs every few years. In 1982 and 1983, El Niño was particularly severe, and this account describes the damage it caused in many … Continue reading
The geological evolution of Africa has been hinged on stability. Africa contains three major cratons, or areas of basement-complex rock that have been geologically stable for hundreds of millions of years. The Kalahari craton is located in southern Africa, the Congo craton is in Central Africa, and the northwest African craton, forming the core of West Africa, is centered in the Western Sahara. Areas between the cratons contain somewhat younger rocks. These areas have undergone more extensive and continuing geological change since the late Precambrian Period, caused by processes such as faulting, volcanism, folding, and crustal displacement. The stability of the areas of basement-complex rock has helped define the geological evolution of Africa.
Acid rain falls into and drains into streams, lakes, and marshes. Where there is snow cover in winter, local waters grow suddenly more acidic when the snow melts in the spring. Most natural waters are close to chemically neutral, neither acidic nor alkaline: their pH is between 6 and 8. In the northeastern United States and southeastern Canada, the water in some lakes now has a pH value of less than 5 as a result of acid rain. This means they are at least ten times more acidic than they should be. In the Adirondack Mountains of New York State, a quarter of the lakes and ponds are acidic, and many have lost their brook trout and other fish. In the middle Appalachian Mountains, over 1,300 streams are afflicted. All of Norway’s major rivers have been damaged by acid rain, severely reducing salmon and trout populations.
- Effects of Acid Rain on Plants and Animals (egrejeen.wordpress.com)
- Effects of Acid Rain on Agriculture (egrejeen.wordpress.com)
- Effects of Acid Rain on Human Health (egrejeen.wordpress.com)
- Effects of Acid Rain on Human-Made Structures (egrejeen.wordpress.com)
Effects of Acid Rain on Plants and Animals
The effects of acid rain on wildlife can be far-reaching. If a population of one plant or animal is adversely affected by acid rain, animals that feed on that organism may also suffer. Ultimately, an entire ecosystem may become endangered. Some species that live in water are very sensitive to acidity, some less so. Freshwater clams and mayfly young, for instance, begin dying when the water pH reaches 6.0. Frogs can generally survive more acidic water, but if their supply of mayflies is destroyed by acid rain, frog populations may also decline. Fish eggs of most species stop hatching at a pH of 5.0. Below a pH of 4.5, water is nearly sterile, unable to support any wildlife.
Land animals dependent on aquatic organisms are also affected. Scientists have found that populations of snails living in or near water polluted by acid rain are declining in some regions. In The Netherlands songbirds are finding fewer snails to eat. The eggs these birds lay have weakened shells because the birds are receiving less calcium from snail shells.
Acid rain and the dry deposition of acidic particles damage buildings, statues, automobiles, and other structures made of stone, metal, or any other material exposed to weather for long periods. The corrosive damage can be expensive and, in cities with very historic buildings, tragic. Both the Parthenon in Athens, Greece, and the Taj Mahal in Agra, India, is deteriorating due to acid pollution.
Air Pollution is the addition of harmful substances to the atmosphere resulting in damage to the environment, human health, and quality of life. One of many forms of pollution, air pollution occurs inside homes, schools, and offices; in cities; across continents; and even globally. Air pollution makes people sick—it causes breathing problems and promotes cancer—and it harms plants, animals, and the ecosystems in which they live. Some air pollutants return to Earth in the form of acid rain and snow, which corrode statues and buildings, damage crops and forests, and make lakes and streams unsuitable for fish and other plant and animal life.
Pollution is changing Earth’s atmosphere so that it lets in more harmful radiation from the Sun. At the same time, our polluted atmosphere is becoming a better insulator, preventing heat from escaping back into space and leading to a rise in global average temperatures. Scientists predict that the temperature increase, referred to as global warming, will affect world food supply, alter sea level, make weather more extreme, and increase the spread of tropical diseases. Although some countries have put in place some legislation to control air pollution, others continue to lag behind and hence contributing to the ever increasing pollution of our environment.
The principal environmental effect of the aftermath of the Chernobyl’ accident has been the accumulation of radioactive fallout in the upper layers of soil, where it has destroyed important farmland. The second most important impact has been the threat to surface water and groundwater. The cleanup in some of the most heavily contaminated areas within the evacuation zone, such as Pripyat’, involved the stripping and burying of topsoil and vegetation, the sealing of wells, and the building of structures designed to prevent surface water from entering streams and rivers that drain into the Dnieper River system, which provides Kyiv’s water supply.
By most measures, the country most seriously affected by the accident is Belarus (which changed its name from Belorussia after it, along with the other Soviet republics, became independent with the collapse of the USSR in 1991). Almost 20 percent of the republic’s farmland was removed from production during the years immediately after the accident. Half of the vast 27,850-sq km (10,750-sq mi) area described as being ‘seriously contaminated’ by radiation (with levels of radioactive cesium in topsoil exceeding 5 curies) is in Belarus. The regions commonly identified as experiencing the greatest contamination include the oblasts (regions) of Homyel’, Mahilyow, and Brest in southern and eastern Belarus; Kyiv, Zhytomyr, and Chernihiv in northern Ukraine; and Bryansk in southwestern Russia.
Effects on public health have been more difficult to figure and are subject to much controversy. It is not always clear which health problems are caused directly by radiation and which are caused by poor nutrition, the general low level of health, and the anxiety and stress produced by fear of radiation exposure. These issues surround the debate over the causes of higher death rates among the more than half a million workers who participated in the Chernobyl’ cleanup.
However, at least one type of cancer can be attributed directly to Chernobyl’. There has been a significant rise in the incidence of thyroid cancer among children in the areas where radiation levels are highest. Thyroid cancer rates in Homyel’ Oblast, for example, increased 22-fold from 1986 through 1990 compared to the period from 1981 through 1985.
Many observers have argued that the accident at Chernobyl’ accelerated the transformation of the USSR toward a more open society. Soviet officials, unable to conceal the accident from the world, reluctantly acknowledged the accident during an evening news telecast in Moscow on April 28 and in brief newspaper accounts on April 30. This was followed by regular coverage focused on the cleanup efforts in the months that followed. This reporting sharply contrasts to the lack of coverage of earlier catastrophic events (an accident at a nuclear weapons plant in the Ural Mountains in 1957 and major earthquakes in Central Asia in 1948 and 1964).
Also, after the accident several key officials in the Soviet nuclear power industry were dismissed, punished, or both, and a new Ministry of Nuclear Power was created in 1986. Before then, officials in the general electric power ministry had overseen nuclear power. Chernobyl’ also called into question the basic safety of nuclear power in both the USSR and several Eastern European countries whose power plants contained reactors based on the RBMK reactor design used at Chernobyl’. (In the RBMK design, there is no containment shell, the graphite blocks used to moderate the fission reaction are flammable, and excess steam in the reactor core will cause the nuclear reaction to increase). As a result, international organizations, such as the International Atomic Energy Agency, became involved in programs to improve safety rules and upgrade the design of RBMK reactors in the USSR and Eastern Europe.
The accident, coupled with a general economic decline that set in during the last years of the USSR, also resulted in a dramatic scaling back of Soviet plans to use nuclear power to generate the bulk of electric power in Soviet regions remote from oil and gas energy resources. In Ukraine, opposition to further nuclear construction in the immediate post-Chernobyl’ years was particularly intense. In August 1990, for example, the Ukrainian parliament declared a moratorium on nuclear power plant construction. This ban was later lifted in 1993 because of severe energy shortages in Ukraine.
Earlier in 1990 the Ukrainian parliament had voted to close the Chernobyl’ plant permanently within five years, but closure was repeatedly postponed because of the country’s shortage of electricity-generating capacity. After a turbine fire in October 1991, the No. 2 reactor at Chernobyl’ was shut, leaving only two of the original four reactors at the plant in service. Reflecting mounting safety concerns in the international community, an agreement was concluded in April 1996 between the Ukrainian government and the G-7 countries (Group of Seven major industrial nations) to decommission the Chernobyl’ plant by the year 2000. In conjunction with the agreement, the G-7 countries pledged $300 million to finance programs to strengthen the sarcophagus, which some fear may collapse, and for more cleanup work. In November 1996, as part of the schedule for the decommissioning, the No. 1 reactor at Chernobyl’ was taken out of service, leaving only the third unit working. Finally, in December 2000 the plant was totally shut down. Although contained, the Aftermath of the Chernobyl’ Accident is one indicator of how dangerous nuclear power is whether for civilian or military purposes.
The Efforts to Control Acid Rain by International Agreements is often necessary to control its spread across borders. Acid rain typically crosses national borders, making pollution control an international issue. Canada receives much of its acid pollution from the United States—by some estimates as much as 50 percent. Norway and Sweden receive acid pollutants from Britain, Germany, Poland, and Russia. The majority of acid pollution in Japan comes from China. Debates about responsibilities and cleanup costs for acid pollutants led to international cooperation. In 1988, as part of the Long-Range Trans-boundary Air Pollution Agreement sponsored by the United Nations, the United States and 24 other nations ratified a protocol promising to hold yearly nitrogen oxide emissions at or below 1987 levels. In 1991 the United States and Canada signed an Air Quality Agreement setting national limits on annual sulfur dioxide emissions from power plants and factories. In 1994 in Oslo, Norway, 12 European nations agreed to cut sulfur dioxide emissions by as much as 87 percent by 2010.
Legislative actions to prevent acid rain have results. The targets established in laws and treaties are being met, usually ahead of schedule. Sulfur emissions in Europe decreased by 40 percent from 1980 to 1994. In Norway sulfur dioxide emissions fell by 75 percent during the same period. Since 1980 annual sulfur dioxide emissions in the United States have dropped from 26 million tons to 18.3 million tons. Canada reports sulfur dioxide emissions have been reduced to 2.6 million tons, 18 percent below the proposed limit of 3.2 million tons.
Monitoring stations in several nations report that precipitation is actually becoming less acidic. In Europe, lakes and streams are now growing less acid. However, this does not seem to be the case in the United States and Canada. The reasons are not completely understood, but apparently, controls reducing nitrogen oxide emissions only began recently and their effects have yet to make a mark. In addition, soils in some areas have absorbed so much acid that they contain no more neutralizing alkaline chemicals. The weathering of rock will gradually replace the missing alkaline chemicals, but scientists fear that improvement will be very slow unless pollution controls are made even stricter. International agreements however have aided various efforts to control acid rain around the world.
- Efforts to Control Acid Rain (egrejeen.wordpress.com)
- Efforts to Control Acid Rain and its implication on National Legislation (egrejeen.wordpress.com)