Causes of Climatic Change - Essay Example

Causes of climatic change Climate change refers to the change in the climatic distribution of weather patterns over a period. The period is a long time, ranging from a decade to a million of years. During the period, there is change of several weather conditions in between. After a study and classification of these weather events over a decade or so, scientists obtain the climate of the region (Letcher 2). However, the weather in a given area is in constant change every given time. Thus, the climate of a region keeps on changing over decades. Change in the climate of a given region, is because of natural and human induced factors on the environment. This paper discusses three factors that cause change in the climatic conditions of an area. These three factors include oceanic circulations, global warming and volcanic radiations. Volcanic activity is a natural factor that causes climatic change. When volcanic eruptions occur, they inject quite a large amount of duct and other gaseous elements into the stratosphere. One of the gaseous elements that reach the stratosphere is sulphur dioxide (Letcher 81). On reaching the stratosphere level, sulphur dioxide converts rapidly to form sulphuric acid aerosols. The aerosols formed continue to spread gradually covering the whole world at the stratosphere. The effects of volcanic eruptions at the stratosphere, do not wear out as fast as the effects at the lower level (Letcher 81). This is because at the lower level, the effects of gravity and rainfall, contribute to the recovery of the volcanic effects at that level. The covering at the upper level, which constitutes sulphuric acid aerosols, reduces the direct solar beam to the earth surface. The reduction is because of the high reflective property of sulphuric acid aerosols (Letcher 81). Despite the compensation provided by the green house effect and diffused radiations, there is still a reduction in the amount of solar energy received on the earth’s surface. This causes a shift in energy balance on the earth’s surface. Scientific studies show that a single volcanic activity may cause a shift of 0.3 degrees. Further, the effects of a single activity last for a period of two years. However, a single eruption is unlikely to cause a drastic change in the climate of a region (Letcher 83). The effects of volcanic activity on climate are in a long time scale, such as millions of years. Over millions of years, continuous volcanic activity, releases huge volumes of greenhouse gases, which causes global warming. On the other hand, sulphur dioxide emissions will counter the effects of global warming. Therefore, the result of the process on the climate remains uncertain, leaving other external factors, such as the nature of the volcano, to determine the change (Letcher 84). Ocean circulation is another significant factor that results to a change in the climatic conditions. This is because oceans too, play a role in the global climate system. Oceans store a large amount of heat energy. Ocean circulation is a force that causes a change in the global heat balance on Earth (Samelson 29). Major theories in ocean circulation, depict the changes in the North Atlantic Deep Water (NADW) production and thermohaline circulation, to be cause of climatic change. However, scientists have focused more on the climatic transitions that occurs between the interglacial and glacial occurrences (Samelson 29). The Gulf Stream carries heat polewards, to warm the north maritime Europe. The North Atlantic contains cold polar air (Samelson 30). On meeting the cold polar air, the warm water, releases heat to the atmosphere. The cooling water sinks with the help of the increased salinity in the region. Increase in salinity is a result of the presence of sea ice, which is present in the Arctic regions (Samelson 30). The cooling water will thus sink because of an increase in density, forming the North Atlantic Deep Water. The NADW flows through to the Pacific Ocean via western Atlantic, all the way around Australia and South Africa (Samelson 30). However, since the North Atlantic is warmer, it experiences an increase in evaporation. Therefore, it increases the level of salinity in the North Pacific. The increased level of salinity in the region, initiates the global thermohaline ocean circulation. The formation of NADW reduces drastically during a glacial period. Therefore, the ice blocks at the Arctic region, moves further south into the North Atlantic. When the ice blocks move south, the position of the polar front will shift towards the south too (Samelson 31). This ice blocks reduce the surface temperature, leading to a consequent reduction in the rate of evaporation at that region. Consequently, the cooler temperatures relate to the increase in salinity, which will further preclude the beginning of thermohaline circulation in the region (Samelson 31). In addition, since there is no warm surface Gulf Stream, the temperature in the region could drop with a significant 8 degrees, as compared to the interglacial periods. The forces that cause a change in the patterns of the glacial and interglacial periods, on the circulation of thermohaline in the region, are internal climate forces (Samelson 31). If the change in the salinity levels around the globe is great enough, it could drastically reverse the circulation of thermohaline all around the globe. This theory explains the reasons for several post-glacial fluctuations in the climate, over many years ago, especially when the North Atlantic region cooled by several degrees (Samelson 31). However, if the North Atlantic heat system shuts down, there will be no climate changes. The shutting down of the heat system in the region is not adequate to start global temperature changes and the development of ice blocks (Samelson 32). Scientists believe that other internal mechanisms need stimulation, to have a change in the climatic conditions (Samelson 32). Some of the mechanisms that need initiation include changes in the levels of concentration of aerosol loading, concentration of the greenhouse gases, a reduction in the rate of transfer of ocean heat, and an increase in the level of ocean alkalinity (Samelson 33). These factors are internal mechanisms that regulate the balance of atmospheric concentration in the Atlantic regions. Natural and anthropogenic factors, cause changes in the level of greenhouse gas content of the atmosphere. However, the natural factors such as, humankind burning fossils and clearing forests, have caught the attention of scientists more than the anthropogenic factors. This has increased the level of carbon dioxide in the atmosphere. The greenhouse gases concentration changes as a response to other natural factors. This is evident during changes in the ocean circulation (Samelson 15). During the transitions between the interglacial episode and the glacial episode, there is a change in the level of carbon dioxide and methane gases in the atmosphere. The changes in the concentration of the above gases, acts as a feedback mechanism since they remain behind the climate signal (Samelson 15). The change in the concentration of the aerosols too, has natural and anthropogenic factors that cause its change. When the concentration of aerosol, atmospheric turbidity, increases, it affects atmospheric energy. Atmospheric turbidity increases the spreading of the solar radiations that come through (Samelson 16). In addition, the atmospheric turbidity is higher during the glacial episode than during the interglacial episode. Therefore, there is an adequate amount of reduction in the level of direct sun radiation, which reaches the Earth’s surface during the glacial episode. This process further explains the cooling effect associated with the glacial episode during ocean circulation. Climatic changes caused by ocean circulation are non-radiative. This is because; it involves energy transfer in the ocean components only in that climate system (Letcher 84). Global warming is another major factor that causes a change in climatic conditions. Global warming refers to the increase in the average temperature of the Earths atmosphere. Statistics show that the level of surface temperature has risen by 0.8 degrees since the beginning of the twentieth century (Booker 2). The rise in temperature is majorly a result of human activities such as burning fossil fuels, deforestation and emissions from industries. Scientific study through satellites shows that the Sun’s output has not increased for a long time. Therefore, the increase in the warming on the Earth’s surface does not relate to an increase in solar energy produced by the Sun. Evidence against the Sun’s role in increase on temperature depict that temperature on different levels of the atmosphere have changed. Green house warming, results to the increase in temperature in the troposphere, and a decrease in temperature on the stratosphere (Booker 78). The stratosphere level falls higher above the troposphere level. Therefore, if the sun could be responsible for the increase in temperature, the stratosphere could be hotter than the troposphere, which is not the case. The greenhouse effect is part of global warming. Greenhouse effect refers to the process where by gases absorb and emit infrared radiation to the atmosphere, thereby, warming Earth’s surface and lower atmosphere (Booker 77). There are naturally occurring greenhouse gases, which are responsible for a warming effect of 33 degrees. These gases are a combination of carbon dioxide, methane, water vapor and ozone. The clouds too, through cloud forcings, affect the radiation balance (Booker 77). Global dimming refers to the gradual reduction in direct irradiance effect in the Earth’s surface. Its main cause is the particulates produced during volcanic activity, together with other human pollutants. Global dimming increases the rate of reflection on the incoming sunlight, there by causing a cooling effect on the Earths surface. In conclusion, the factors that cause the change in climatic conditions are inter-related. Not just one factor on its self is capable of causing a drastic change in the climate of a given region. In addition, factors that cause climatic change are both natural and influenced by man. Human activities such as deforestation, burning of fossil fuels and industries have a direct influence on the factors that cause climate change. To control the rate of climate change, mankind should use environment friend mechanisms in daily activities. The process of climate change is gradual process that may take thousands of years to complete. Works Cited Booker, Christopher. The Real Global Warming Disaster: Is the Obsession with 'climate Change' Turning Out to be the Most Costly Scientific Blunder in History? New York: Continuum International Publishing Group, 2011. Print Letcher, Trevor. Climate Change: Observed impacts on Planet Earth. San Francisco: Elsevier, 2009. Print Samelson, R. M. The Theory of Large-Scale Ocean Circulation. London: Cambridge University Press, 2011. Print Read More