Impact of Global Warming on Human Health - Essay Example

IMPACT OF GLOBAL WARMING ON HUMAN HEALTH Global warming, its scope and causes Global warming refers to the increase in the overall temperature of the atmosphere, ocean bodies and the landmasses of our planet. Global warming followed by cooling is a geological phenomenon. During the past 4.5 billion years, planet earth has warmed and cooled many times. Presently, it is undergoing a very rapid warming, which is the outcome of human activities like rampant and indiscriminate deforestation and reckless exploitation of natural resources for industrialization. One of the main causes of this rapid warming has been attributed to burning of industrial fuels like coal, oil and natural gas. Upon combustion, fossil fuels like coal and petroleum release green house gases like carbon dioxide. As the quantity of carbon dioxide increases in the atmosphere, the atmosphere becomes a much better insulator and retains an increased amount of solar radiation which in turn increases the overall temperature of the planet. Many scientists believe that the release of carbon dioxide and certain other substances into the air are affecting the earth's climate and causing the average global temperature to rise. There is evidence that the earth's temperature has risen in the past century, but scientists are unable to predict with certainty whether this trend will continue or whether it is definitely linked to human activity. Global warming has many affects. As the temperature increases, there is a possibility of melting of polar glaciers and ice caps. The resulting water would flow into the oceans and increase the volume of the oceans. This would lead to rise of ocean levels. Scientists estimate that the sea level could rise from any where between 9 to 88 centimeters (Hart 2003). Such an increase would submerge low lying coastal areas in many countries of the world. Global warming also affects human health. If the atmospheric temperature is increased due to global warming, more people will get sick or die from heat stress. This may be more due warmer nights, giving the sufferers less relief than due to heat during the day time. There is also a possibility of diseases spreading to new regions. Diseases now found in the tropics, transmitted by mosquitoes and other animal hosts, will widen their range as these animal hosts move into regions formerly too cold for them. Today 45 percent of the world's people live where they might get bitten by a mosquito carrying the parasite that causes malaria; that percentage may increase to 60 percent if temperatures rise (Mastrandrea and Shneider 2003). Other tropical diseases may spread similarly, including dengue fever, yellow fever, and encephalitis. Scientists also predict rising incidence of allergies and respiratory diseases as warmer air grows more charged with pollutants, mold spores, and pollens. Heat stress Heat stress or heat prostration is a condition that is produced by over exertion in hot temperatures. It occurs when the person is subjected to high temperatures or extreme hot dryness. When the body undergoes physical exertion, it perspires which produces sweat. The sweat evaporates to cool the skin and prevents body temperature from rising. Perspiration causes the loss of fluids and salts normally replaced by regularly consuming liquids and food. However, if prolonged, excessive sweating occurs, fluids and salts are not replaced rapidly enough resulting in increase in the viscosity of blood. This causes blood circulation to diminish, affecting the brain, heart, and lungs, and heat exhaustion results. Symptoms of heat exhaustion include heavy sweating; pale, clammy skin; dilated pupils; a slightly elevated body temperature; and cramps, weakness, dizziness, nausea, vomiting, headache, mental confusion, and sometimes unconsciousness. Heat stress and global warming Incidence of heat stress increases with temperature. Hence the number of cases of incidence of heat stress tends to increase in the very near future due to rise in temperatures because of global warming. Countries where incidence of heat stress may be very low due to colder climates may experience an increase in the incidence due to increase in temperature. According to Karen Hopfl-Harris (No date), "Heat and heat waves are projected to increase in severity and frequency with increasing global mean temperatures. Studies of heat waves in urban areas, which already are extremely vulnerable to health problems related to heat, have shown an association between increases in heat and increases in mortality. Other heat-related health effects include heat cramps, heat exhaustion and heat stroke. Models of weather-mortality relationships indicate that populations in the northeast and mid-western U.S. may experience the greatest number of heat-related illnesses and death in response to changes in summer temperatures. The most sensitive regions are those where extremely high temperatures occur infrequently or irregularly." (Quoted from The potential impacts of global warming on public health No date) Sunstroke or Heatstroke Heatstroke is reaction to intense heat characterized by high body temperature and interruption of the sweating mechanism; it is called sunstroke if caused by long exposure to sun. In heatstroke the skin is hot, red, and dry; the pulse is strong and fast; the victim may be unconscious; and the body temperature is about 41 C (106 F) or higher. Prior to unconsciousness the person may experience dizziness, fainting, tingling, and mental bewilderment. If ignored, heatstroke can often be fatal, because prolonged fever can cause brain damage, shock, or heart or kidney malfunction, especially in persons with underlying disease. Heatstroke is a result of too much sweating during which the body's salts are exhausted. The control of heat regulation by the central nervous system is disturbed and sweating ceases. This leads to the hot, dry skin attribute of the condition. Children and the elderly are more vulnerable than others because their temperature regulating system is less receptive to change. People suffering from obesity are also at greater risk because their bodies dissipate heat with decreased effectiveness. Heat exhaustion is a less severe condition in which a person becomes fatigued and perhaps dizzy or nauseated due to long exposure to heat. Temperature is normal or below normal and sweating persists. First aid entails cooling the person and providing small sips of salt water. Heat exhaustion is sometimes accompanied by cramps, especially of the extremities. These are treated by local massage. Heatstroke and heat exhaustion can be prevented by moderating activity when the temperature becomes very high and maintaining an adequate intake of fluids and salt. Since heat stroke is dependent on temperature, increase in temperature due to global warming will increase its incidence. Heat stroke and global warming Since heat stroke is dependent on temperature, global warming would be responsible for increased incidence of heat stroke or sunstroke. According to Bouchama and Knouchel (2002), "In an epidemiologic study during heat waves in urban areas in the United States, the incidence of heat stroke varied from 17.6 to 26.5 cases per 100,000 population. Most people affected by classic heat stroke are very young or elderly, poor, and socially isolated and do not have access to air conditioning." They further quote, "The threat of heat stroke is increasing. Global warming is already causing heat waves in temperate climates. The recognition that thermoregulatory failure and impaired regulation of inflammatory and stress responses facilitate the progression from heat stress to heat stroke and contribute to the severity of tissue injury should make research in this direction a priority." (Quoted from Heat stroke: The New England Journal of Medicine. 2002) Sunburns Sunburn is a burn to the skin produced by overexposure to ultraviolet (UV) rays, generally from the sun's rays. The risk of sunburn increases with proximity to the earth's equator. It can also be increased by pharmaceutical products that sensitize some people taking them to UV radiation. Certain antibiotics, contraceptives, and tranquillizers have this effect. In recent years, the incidence and severity of sunburn has increased worldwide, especially in the southern hemisphere, because of damage to the ozone layer due to CFCs. Some environmentalists are worried that ozone depletion and the seasonal ozone hole have led to high levels of UV radiation posing threat to the health of inhabitants of equatorial region. Sun burns and global warming Incidence of sunburns is predicted to rise with global warming. The amount of UV radiation and the temperature are directly proportional and thus increase in one is equivalent to increase in another. Thus the incidence of sun burns increases with global warming. Skin cancer Skin Cancer refers to malignancy in the skin, and the most widespread of all cancers. There are three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell carcinoma, the most common type, develops in the basal, or bottom, layer of the epidermis, the top layer of skin. Squamous cell carcinoma, the second most common type, develops in the upper layers of the epidermis. The American Cancer Society estimates that basal cell and squamous cell skin cancers account for more than 1.3 million new cases each year, but for only 1,900 deaths. In Canada, 68,000 new cases of basal cell and squamous cell skin cancer are diagnosed each year. The third type of skin cancer is melanoma. It develops in the melanocytes, or pigment cells, which are found throughout the basal layer. Melanoma is the most dangerous type of skin cancer and is responsible for about three-quarters of all skin cancer deaths. About 48,000 new cases of melanoma are diagnosed annually in the United States, and an estimated 7,700 people die from this disease each year. The incidence of melanoma has been increasing faster in the United States than any other form of cancer, and a person born in the early 1990s is 12 times more likely to develop melanoma than a person born in the early 1940s. In Canada, about 3,100 new cases of melanoma are diagnosed each year. Sunlight that reaches the earth's surface contains two kinds of ultraviolet (UV) radiation. UV-A and UV-B both contribute to sunburn and skin cancer, as well as to conditions such as premature wrinkling of the skin. The U.S. Environmental Protection Agency has determined that depletion of the ozone layer in the upper atmosphere will continue to increase radiation damage to skin and skin cancer rates in the future. Vector borne diseases In addition to coping with heat stress, ultraviolet radiation, and air pollution, residents of developed countries in temperate climates may be faced with new threats from infectious diseases, many of which are spread by vectors that may be more numerous and difficult to control. As with the other climate-related health impacts, assessments of the impact of climate on vector borne diseases are uncertain. According to Robert Shope, professor of epidemiology at the Yale University School of Medicine, "Even the experts don't all agree as to whether certain areas will warm or not, whether they will receive more or less rain. Some vectors have very stringent requirements for their ecosystems. Some can't survive if the temperature gets too high or too low or if the rainfall is too high or low." (quoted by Breslin 1994) A 3C rise in temperature in the United States could increase the range of Aedes aegypti, a mosquito species that can carry the viruses that are responsible for causing dengue and yellow fever. The potency of Aedes aegypti is decreased at lower temperatures. With global warming, these mosquitoes may be found in places where they weren't found before. Moreover, in places where the mosquito is present year-around, the mosquito may become more active. Forms of dengue vary in severity, to which one can be exposed in sequence. One form is not fatal, but causes a fever, body aches, and severe headaches. If infected again, an individual runs the risk of developing a second form of dengue that produces hemorrhagic fever, which is fatal in about 5% of cases, though mortality may be lower in areas where physicians know how to treat the disease. Increased temperatures and rainfall may develop enhanced conditions for the Anopheles mosquito, which carries malaria. Malaria may recur in areas where it was once widespread, before vector-control efforts, although the disease is not expected to be as widespread as before. Areas where malaria is at present common may experience more significant effects. Some of the rodents found in tropical areas are carriers of diseases. In a warmer world, these rodents' range of habitat may increase. They may be more commonly found in colder countries of the extreme northern and southern hemisphere. The diseases that these rodents are responsible for transmitting may be increasingly found in those countries. Shortage of food Global warming is likely to have an impact on fish and on fishing-dependent communities as well. This may lead to shortage of food in certain communities and force a change in food habits. Due to shortage of one of the key food items, the nutritional balance of the diet may be changed. This can lead to malnutrition or nutritional imbalances like vitamin and mineral deficiencies. If the earth heats, the polar ice caps would liquefy, water levels would get higher and the pattern of currents, salinity, and river flows would be altered. Significant marsh and mangrove areas that are home to many species may be submerged. With these changes, researchers would anticipate that some species inside a particular ecosystem to die out or steadily migrate to other areas, perhaps causing a number of fish to become extinct as their food sources vanish. As circumstances change, fish may follow the currents to new feeding grounds, which could have serious financial consequences for states and nations. The extent to which global warming is occurring is still unclear, because there is so much variability in the earth's climate system. Because of this, the immediate effects of global warming are difficult to determine. Some changes in water temperature, believed to be contributing to the death of coral, for example, may be due to normal cyclical changes rather than global warming. Introduction of Exotic Species Also damaging to fish populations is the unintentional introduction of species from one area into another. These exotic species can devour food sources and overrun habitat, disrupting native fish populations. As oceangoing vessels ply the world's seas, they transport water in their holds as ballast for stability. When the ships empty their ballast water, they release larvae, plankton, and other organisms into foreign waters. At any given time, ballast water may transport and release as many as 3000 species of plants and animals around the globe. Change in crop Due to higher temperatures some essential crop in colder countries may fail. Thus the diet may undergo an imbalance causing vitamin and mineral deficiencies or protein-energy deficiencies if the crop under consideration in the staple food. Thus malnutrition may be one of the major consequences of global warming. The impacts that global warming can have on human health are widespread. A warmer world could mean a world with more diseases, malnutrition and high incidence of skin cancer. The human body can withstand and adapt to changes in the surroundings. Past history of humans is a testimony to the adaptive nature of the human body. Decrease in body hairs, bipedal locomotion and a few other distinct features of the human body were to fast adaptation to the surrounding conditions. And yet there is a limit to how fast the human body can change and adapt to the ever changing environment. In the absence of such adaptation, extinction becomes inevitable. There are two ways by which this can be prevented. Global warming is man made. Its solution is feasible if the main fields are identified. Planting more trees and cutting usage of fossils fuels can undo harm that has already been done. The other process is by developing appropriate medical procedures and cures to the diseases that people in the future may encounter. References: John Hart. (2003) Global warming. Microsoft Encarta Reference Library 2003. 1993-2002 Microsoft Corporation. All rights reserved. CD-ROM Mastrandrea and Shneider (2003) Green house effect Microsoft Encarta Reference Library 2003. 1993-2002 Microsoft Corporation. All rights reserved. CD-ROM Hopfl, Harris (No Date). The potential impacts of global warming on public health. Retrieved from http://www.climatehotmap.org/impacts/humanhealth.html (04/30/06 08:20:19) Bouchama and Knouchel. (2002) Heat stroke. The new England Journal of Medicine. Retrieved from http://content.nejm.org/cgi/content/full/346/25/1978 (04/30/06 19:33:37) Kalkstein (No Date) IMPACTS OF GLOBAL WARMING ON HUMAN HEALTH: Heat Stress-Related Mortality. Retrieved from http://www.ciesin.org/docs/001-332/001-332.html (04/30/06 20:22:34) Breslin (1994) Global climate change: Beyond sunburn. Environmental Health Perspectives Volume 102, Number 5, May 1994 Retrieved from http://www.ehponline.org/docs/1994/102-5/focus1.html (04/30/06 19:57:37) Wikipedia contributors (2006). Global warming. Wikipedia, The Free Encyclopedia. Retrieved 01:14, May 1, 2006 from http://en.wikipedia.org/w/index.phptitle=Global_warming&oldid=50907966. Wikipedia contributors (2006). Sunburn. Wikipedia, The Free Encyclopedia. Retrieved 01:16, May 1, 2006 from http://en.wikipedia.org/w/index.phptitle=Sunburn&oldid=50159309 Read More