The Greenhouse Effect and Global Warming - Assignment Example

The Greenhouse Effect and Global Warming The greenhouse effect is a term that describes an increase of the average global temperature and is often associated with global warming which is the subject of great debate and concern worldwide. Although warnings about the human generated causes of an enhanced greenhouse effect and the subsequent catastrophic outcomes have been sounded for over 100 years, global warming has only recently become an important political matter. This discussion will first define the greenhouse effect then explain how naturally occurring and man-made gases affect it along with examples of the consequences of these forces. Essentially, the greenhouse effect functions in the following manner. When sunlight pierces the atmosphere and hits the earth’s surface, not all of the sun’s solar energy is absorbed. Approximately a third of it is reflected back into space. Specific atmospheric gases serve in much the same way as does the glass of a greenhouse, thus the terminology. These gases allow sunlight to penetrate then trap some of the solar energy which heats the earth (Breuer, 1980). It is a delicate balance and because these greenhouse gases have been artificially augmented by man-made sources, more build up in the atmosphere has occurred thus trapping more of the sun’s energy and reflecting less back in to space. This occurrence is causing the earth to warm. Carbon Dioxide (CO2) is the most prevalent of the greenhouse gases. Trees absorb CO2 and when they die, CO2 is restored to the atmosphere. The clearing of forests by mass burning, which is happening at a phenomenal rate in the tropical rain forests, is decreasing the amount of CO2 that is absorbed and increasing the amount that is added to the atmosphere. CO2 supplies about half of the total gases that create the greenhouse effect (Breuer, 1980). Although deforestation is contributing heavily to the excess of CO2 in the atmosphere, a larger portion is caused by the burning of fossil fuels such as oil and coal. Fossil fuels are burned by factories, vehicles and electricity-producing power plants to name a few sources. The vast majority of this excessive fuel consumption and its poisonous, pollutant and greenhouse-enhancing byproducts are located in the U.S., Europe and Russia (Breuer, 1980). Other greenhouse gases include methane, which is released when vegetation is burned during land clearing, during oil exploration activities and the coal-mining process; chlorofluorocarbons (CFCs), which is the substance that cools refrigerators and provides the propulsion in aerosol cans and nitrous oxide (N2O) which is the lesser cause of CO2 (Breuer, 1980). It is generated from both man-made and natural processes. It is estimated that man-made influences represents about half of the CO2 output. The rising levels of carbon dioxide (CO2) in the atmosphere are becoming increasingly disconcerting. “The concentrations of CO2 in the air around 1860 before the effects of industrialization were felt, is assumed to have been about 290 parts per million (ppm). In the hundred years and more since then, the concentration has increased by about 10 percent.” (Breuer, 1980, p. 67). Eighty percent of the world’s population accounts for just 35 percent of CO2 emissions while the United States and Soviet Union combined are responsible for generating half. Worldwide, “carbon dioxide emissions are increasing by four percent a year.” (Miller, 1990, p. 450). Motor vehicles are a major cause of air pollution as is fuel burned for the heating of homes and powering industry along with the toxins emitted from stacks at coal-burning power plants. “Vehicles produce high levels of carbon monoxides (CO) and a major source of hydrocarbons (HC) and nitrogen oxides (NOx), whereas, fuel combustion in stationary sources is the dominant source of sulfur dioxide (SO2)” (Breuer, 1980, p. 70). If the balance between the CO2 levels in the ocean and atmosphere is disturbed by interjecting increasing amounts of CO2, the oceans would continually absorb higher concentrations than it does naturally. The subsequent warming ocean waters are less effective in their ability to absorb CO2 and when the oceans can no longer keep pace with the intrusion of this naturally equalized cycle, then more CO2 will remain in the atmosphere. Increasing the amount of CO2 in the atmosphere is expected to result in a warming of the Earth’s surface accelerating the greenhouse effect. “Currently carbon dioxide is responsible for 57 percent of the global warming trend. Nitrogen oxides contribute most of the atmospheric contaminants” (Miller, 1990, p. 498). The scientific community agrees that global temperatures are rising due to the burning of fossil fuels which are damaging the protective atmospheric Ozone layer by changing its composition. Human pollution is changing the climate of our earth and has increased global warming in the past half century. The effects are being felt worldwide, not just in the U.S. where most of the CO2 emissions are generated. In the UK., for example, four of the five warmest years for more than three centuries have occurred in the last 10 years. Scientists predict that in 50 years, annual temperatures in the south east of England could be at least three degrees (Fahrenheit) warmer, on average, than they are now (Climate Crisis 2000). Global warming is further evidenced by the well-documented melting of glaciers along with thermal expansion of the oceans, which have contributed to an increase in sea level over the past century of about six inches in that country. (Trenberth 1997). Studies have been conducted by the National Aeronautics & Space Administration (NASA) demonstrated that the past decade has been the warmest on record. At first thought, especially during the cold winter months, a little warming wouldn’t seem to be such a bad thing. Several varieties of fruits and vegetables could be produced in northern climates that today only grow in warmer climates. Warmer seas are likely to be attractive to more species of fish to the colder habitats as well. This is not to mention additional tourist currency to what would be the warm, sandy beaches of Canada or England (Climate Crisis 2000). However, as in everything, there is a downside and in this case, one of horrific proportions. Studies in the UK have found that warming could increase rainfall by more than 20 percent during the winter by the 2080’s and decrease it by the same amount during summer months in the southern half of that country. This would cause severe droughts in some regions but areas such as East Anglia, a very low-lying region on the east coast of England, could very well be under water altogether. One would have to wonder what enormous problems this will cause not only to people and property but to the health of the global economy as a whole. Entire sections of various countries will be forced to abandon their homes and businesses. The process will be a slow and torturous one. Scientists also worry about the effects of a changing climate on the Gulf Stream, a massive ocean current which acts to warm the continent of Europe. “Ocean currents transport large amounts of heat around the world: climatologists call it thermohaline circulation (THC)” (Climate Crisis 2000). If it slows down or moves further south as a result of Greenland melting, Europe could end up with a climate more like that of present-day Greenland. A BBC-produced television programme documented recently that Greenland is in fact melting at an alarming rate providing photographic evidence taken in the 1970’s in contrast to photographs taken in the present day. Future scenarios for greenhouse gas quantities, especially regarding CO2 and CH4, are hardly an exact known when attempting to project future climate changes. Formulating the net greenhouse effect is complex because of its associations to supplementary aspects of energy cycles. However, the period of time that records have been kept is sufficient now so as to make comparative trends regarding the effects of climate change. One of the problems regarding to measuring global warming is that the phenomenon is not occurring in an obviously uniform and steady manner. Many areas of the world, in fact most, experience a wide variation of temperature and climactic effects from year to year. Thus the feedback from studies are vulnerable to challenges made by a minority of scientists, politicians and other citizens who have, for whatever reason, an agenda that compels them to rebuke the overwhelming evidence that man-made causes are accelerating the greenhouse effect. The effects of melting snow caps and the resulting rise of sea levels have been well documented. Other effects are known but not as universally. A reduction of snow cover in addition to lake and sea ice will have dire consequences for locations at higher latitudes and lower elevations, especially in the winter and spring months. At increased temperatures, the atmospheric water vapor and resulting precipitation will be proportionately higher. Cloud compositions will change which will amplify the greenhouse effect. The increased levels of precipitation because of the warming at the Polar Regions will increase the effect. Shifting vegetation patterns, types and regional variations, will cause major human adaptations, the degree to which is open to speculation. The elevated evaporation rate will hasten the drying effect of soil subsequent to rainfall which will result in drier conditions in many regions. Places that presently suffer through periodic drought conditions in the warmer months will be hardest hit. The more rapid water recycling rate will result in heavier rainfall amounts and the number of extreme rainfall events. Higher rainfall rates will cause increased tropical storm intensity in addition to the warmer temperatures. Hurricanes may be even more frequent and intense than presently predicted. As horrific as this near-future scenario is, it remains the land masses that will suffer the greatest changes as a result of the greenhouse effect. “Temperatures are expected to increase more rapidly over land compared to oceans because of the ocean’s higher heat capacity and because it can transfer more of the trapped heat to the atmosphere by evaporation. Over land, the warming has been and is expected to continue to be larger during nighttime than during daytime” (“Climate Change Impacts” p. 19). Most scientists worldwide accept the sufficient evidence that suggests global warming is already well underway and cannot be reversed anytime soon. They and reasonable people of all backgrounds and nationalities agree that if CO2 emissions are not greatly reduced and soon, the resulting greenhouse effect will alter the climate and possibly the sustainability of humankind. The projected rate of climate change is very alarming to many scientists but not as much to politicians as this topic isn’t as high on the political agenda as some others. World leaders have no sense of urgency about them regarding global warming. They place great importance on the popular items of the day such as education, crime, economics and war so as to be reelected but if they don’t address this issue, there will be nothing to politicize in the future as we will have no future. References Breuer, Georg. (1980). Air in Danger: Ecological Perspectives of the Atmosphere. New York: Cambridge University Press. Quotations used from this book can be located at http://healthandenergy.com/air_pollution_causes.htm “Climate Crisis: All Change in the UK?” (November 12, 2000). BBC News. Available 4 June, 2009 from “Climate Change Impacts on the United States: The Potential Consequences of Climate Variability and Change” (2001). The U.S. National Assessment. U.S. Global Change Research Program. Cambridge University Press. Available 4 June, 2009 from Miller, G. Tyler. (1990). Living in the Environment: An Introduction to Environmental Science. Belmont: Wadsworth. Quotations used from this book can be located at http://healthandenergy.com/air_pollution_causes.htm Trenberth, Kevin E. (1997). “Global Warming: It’s Happening.” National Center for Atmospheric Research. Available 4 June, 2009 from Read More