Sample Term Paper On Climate Change
Climate change is the shifting of the weather patterns and conditions characterized by the various indicators. It is also identified with the shifting of the average conditions of the weather and occurrence of extreme events. The climate of the Earth is affected by natural factors that externally induce changes to the cycle of the climate. The phenomenon of climate change is not a new thing. In fact, it has occurred many times in the historical periods. The various causes that trigger climate change are associated with various factors. There are two major contributory factors for climate change that includes the natural causes and the man-made activities. This paper explores the natural causes of climate change. Evidence of the factors is based on the historical events that occurred thousands of years ago. These factors include the astronomical causes, atmospheric causes, and the tectonic causes. The events that occurred in the past are due to these natural causes. This paper presents the natural causes of the climate change, discussing their respective contributions to the atmospheric conditions and stating their known effects in the geological historical events. It points out the natural cause of climate change as the viable and feasible conclusions for climate change rather than the consideration of the various anthropogenic causes.
Climate change is the shifting of the weather conditions characterized by the changes in the patterns of the wind, precipitations, temperatures, and other indicators. It is also identified by the shift in the average conditions and occurrence of extreme events. The earth is naturally capable of balancing and regulating the energies that comes in and out of its atmosphere. Its natural tendencies to counter the natural variables are applicable on all time scales. Factors that cause sustained long term changes to the amount of the incoming or outgoing energy lead to the climate change. These climate forcers push the climate into a new state of long term climate condition that may be either cooler or warmer states. These various factors are operating in various time scales.
The climate of the Earth is affected by natural factors that externally induce changes to the cycle of the climate. Some of these factors include volcanic activity, the orbit of the Earth around the sun, and the solar output. There are two major factors that cause climate change. The first one is the natural processes and the other is the human factor. Nowadays, most of the blame for climate change is due to the anthropogenic factors while the natural contributory factors brought by nature have been disregarded. This paper focuses on the natural factors that contribute to the climate change.
Pre-Industrial Era: Global Warming
Climate change is already a prevalent phenomenon since the pre-industrialization era. Global warming, a major cause of climate change has been existent around 18,000 years ago since the Pleistocene Ice Age. At that time, the earth is still composed of ice and glaciers where the major continents of Europe, Asia, and North America are buried beneath a large spread of ice and glaciers. The Earth experiences interglacial periods, where the climate naturally warms up every 100,000 years that last for 15,000 to 20,000 years. The Interglacial warm period that naturally happens has caused massive alterations to the environment and the distribution of the life diversity on Earth.
The factors that caused climate change are greatly influenced by the rotation and orbit of the Earth and the variation of the energy output of the sun. Greenhouse gases are contributory factors but it consists of only 0.2 – 0.3% to the total greenhouse effect. The major causes for the global shifting of the temperature are greatly due to natural factors. The Earth has been warming due to astronomical causes, atmospheric causes, and tectonic causes (Hieb, 2007)
The astronomical theory of the climate change (Milankovitch Theory) provides an explanation for the changes encountered with the Earth’s seasons as a result of the Earth’s orbit movement around the sun. The orbit of the Earth is not a perfect circle. There are points that are closer to the sun while there are points where the Earth is far from it. The eccentricity of the earth’s orbit has a cycle of 100,000 to 400,000 years. The tilting of the earth at certain point in the orbit affects the severity of the climate seasons of the Earth.
Malkovitch Theory named after the astronomer Milutin Milankovitch provided calculations about the earth’s orbit movement around the sun with careful considerations of the stars placement and the factors of gravitational pull of other planetary objects. He stated that the earth wobbles along its orbit. The natural tilt of the planet caused the variations of seasons and the changes of the tilt affected the strength of the seasons. The seasons are modified in accordance to the degree of roundness or eccentricity of the path of the earth around the sun. The precision effect and the solstices positioning in the annual orbit of the earth with the sun also contribute to the severity of the changes of the season.
There is an orbital change that occurs every thousands of years as a result of the climate’s response to the orbital forcing. According to theories, the primary force during the ice age is the amount of radiation that the earth received in the latitude zones, 65 degrees north, where most of the major ice formations are found. As calculated, the 65N summer insolation was expected to increase over the next 25,000 years (NOAA, 2009). The Milankovitch cycles, shown in figure 1, reveal that the earth is receiving a various cycle of radiation coming from the sun at every latitudes of the earth. The astronomical precision of these cycles .can be calculated. It holds strong evidence of the cycles that the earth is experiencing since the ice ages. The figure 1 shows the cycles that influence the ice age cycles affected by T’(tilt) of the Earth’s axis; E’ is the orbit eccentricity and P’ denotes the precision (IPCC, 2007).
Figure 1. Milankovitch Cycles: The Schematic diagram of the Earth’s orbital changes (IPCC, 2007)
The solar radiation coming from the sun contributes to the climate change. The radiation balance of the earth affects climate change in three different ways: (1) the change of the incoming solar radiation, (2) the fraction of the solar radiation, and (3) the alteration of the radiation of the long wave energy that radiates back to the space (IPCC, 2007). The sun is a major factor of climate change. The sunspots, the outermost layer of the sun, have a strong radial magnetic field where its cycle is about 22.2 years with fluctuations of 25 months. The total solar irradiance increases the sunspots that deliver more energy to the earth’s atmosphere thereby resulting to an increase in the temperature of the earth. The sunspot-induced changes and solar irradiance combination cause an increase in the atmospheric greenhouses gases that contributes to the increase of the temperature of the earth (Geerts and Linacre, 1997).
The temperature of the Earth is affected by the energy leaving and entering the system of the planet. The sun naturally gives off energy to the earth providing natural warmth to the Earth’s atmosphere. The warmth of the sun reflects back to space to avoid the Earth from getting extremely warm. The major climate change during the pre-industrialization period that dates back from thousands of years are analyzed through indirect measures of climate change such as glacier lengths, ice cores, pollen remains, tree rings, and ocean sediments. The climate change at that time was due to the natural causes such as the volcanic eruptions, solar energy, and greenhouse gases concentrations.
The sunlight that reaches on the surface of the Earth can be absorbed or reflected by the Earth. When the energy is absorbed by the Earth’s atmosphere, the Earth releases infrared radiation into the atmosphere. The Greenhouse gases such as the Carbon Dioxide (CO2), water vapor (H2O) , and methane (CH4) absorbs this heat energy retaining the heat in the atmosphere and prevents the release of this energy into the space. GHGs are like blanket that warm the Earth through the process called ‘greenhouse effect’. During the major climate change in the past, the levels of CO2 were tracked in the glacial cycles. During the interglacial periods, the level of carbon dioxide also increased. But in the cooler ‘glacial’ periods, the levels of the CO2 were also low. The cooling and the heating of the Earth caused changes in the concentrations of the GHG. In the carbon dioxide concentration during that period shown in Figure 2, the changes of the level of the CO2 concentrations at the top and the temperature of the Antarctica at the bottom were estimated based on the data analysis coming from ice cores dated around 800,000 years. The natural factors causing theCO2 concentrations to vary were found out to range from 180 to 300 ppm by volume. Thus, the high concentration of CO2 coincides with the warm periods experienced at that time (US EPA, 2014).
Figure 2. CO2 concentration
The reflectivity also contributes to the climate change. The sunlight that reaches the earth tends to be reflected by light colored objects such as clouds, snow, and polar ice caps while the darker objects tend to absorb light. Reflectivity is the amount of reflected solar radiation from an object. The earth tends to reflect around 30% of the sunlight, while the rest of the 70% is absorbed. The changes in the reflectivity such as the increase of cloud covers and the sea ice melting are considered as feedbacks. The volcanic particles emitted by the volcanic eruption help reflect sunlight back to the space. This action contributes to about few tenths of the cooling of the earth’s surface that could take for several years. These cooling aerosols coming from the volcanic eruptions have sort-lived retention time in the atmosphere as compared with the GHGs (US EPA, 2014).
The displacements with the plate tectonics whether horizontal or vertical contribute a vital role in the Earth’s climate change over a various time scales. The solid form of the earth is directly in contact with the Earth’s atmosphere, the oceans, and the radiation received by the planet. The tectonic movements contribute indirect effects to the climate through the geochemical cycling control and the atmosphere and ocean compositions. The Earth’s surface is made up of large plates that move at a rate of about 3 cm per year. The shifting of the plates caused them to change from one direction to another by virtue of the convection currents underneath. The main force that generates heats to cause the massive movements of the tectonic plates is due to the radioactive decays found at the core of the Earth. There is a continental drift that occurs influenced further by seismic and volcanic activities on the margins. In effect, natural events happen such as earthquakes, mountain developments, and volcanic eruptions. The effect of the tectonic movement in the climate change influence changes on the currents of the ocean that adds up to the heat of the Earth. The shifting of the tectonic plates creates volcanic eruptions that releases off carbon dioxide and sulfur dioxide to the atmosphere. These gases contribute greatly to the temperature increase of the atmosphere. The increase of SO2 in the atmosphere heats up the atmosphere four times as much as CO2 concentration (Cosmato, 2010). The primary input of the CO2 also includes mantle outgassing at the spreading centers of sea floors and the volcanoes, the process of metamorphism of the carbonate rocks along the marginal subduction zones, and the respiration processes of the organic matter burning. The sinks for long-term CO2 are contributed by organic matter decays and the silicate rocks weathering forming carbonates. Mountain building like the Himalayan-Tibetan Plateau uplift also contributes to the carbon dioxide drawdown, until is glaciation through the increase rate of weathering. The oceanic productivity that increase the nutrient delivery and the massive organic carbon decay further adds up to the CO2 amount of the atmosphere (DeConto, R., 2008).
There are various tectonic processes that directly and indirectly affect the climate change. In the case of the historical event during the ice age, the paleography strongly contributed to the sensitivity of the climate system from the external forces providing a framework for the study of climate change in various time scales. The relative contribution of the concentration of greenhouse gases via the tectonic movements influence the atmospheric compositions. The changes in the oceans and the circulation of the atmosphere as affected by the shifting of tectonic plates may not be as great as the other natural causes. However, the association of the tectonic processes with the change in the environment cannot be contested. Primarily, the volcanic eruptions provide instantaneous effects to the atmospheric temperature and other tectonic forcing pose extreme and immediate consequences in the global atmospheric condition (DeConto, R., 2008).
Climate change is a result of the interplay of various causes. The events and cycles may sometimes overlap and compounded that result to significant temperature patterns and climate trends over a certain period of time. The search for the core reasons for climate change has been debated in the current trends of environmental concerns. However, the study of the historical facts that happened states clear evidence about the nature of climate change.
The study of the Earth’s temperature record is done through the accumulated glacial ice taken from the permanent glaciers of Antarctica, Siberia, and Greenland. The captured bubbles in the ice can be used to determine the methane and carbon dioxide concentrations that relates to the atmospheric temperature. Based on the ice core analysis of historical air temperatures taken at the Actarctic Vostok stations during the year 1987, the relative global temperature was examined. Based on the study, the temperature of the Earth is about 3o C cooler today as compared from 18,000 to 160,000 years ago. As seen in the Figure 3, for the last 160,000 years, the Earth has been under the ice siege with brief intervals of interglacial episodes during the Eemian Interglacial (125,000 years ago) and the present Interglacial (18,000 years ago) (Hieb, 2007).
Figure 3. Interglacial episodes of the Earth (Hieb, 2007).
The existence of the Antarctica continent at the southern pole of the Earth will eventually pull back the glacial ice ages. This occurrence is due to the ice caps that can never contain great thickness of ice over open oceans but can be achieved over a polar continent. The Antarctica was used to be found near the equator, but has moved to the South Pole via the continental drift over a geologic period of time. The polar ice caps of the continent serves as great cold sinks that takes over the climate growing even bigger during various periods when solar output is reduced. These ice caps also cause reflectivity of the solar radiation back to the space that further perpetuates the global cooling. The increase in reflectivity results to more cooling effect. The continental ice play vital role in the ice ages when the continental arrangement of the land masses restrict the movement and circulation of the equatorial ocean currents. This happened during the Carboniferous Ice Age when the Pangea, a supercontinent, extends from the north pole to the south pole sometime around 300 million years ago.
The issue with climate change is a natural phenomenon contributed by the factors that naturally happen while the Earth is rotating and revolving around the sun. For hundreds and thousands years, the cycles of the climate change has always been in the move and will have another period of change sometime soon. The changes accord to change in the future as it always does. The calculation of the climate’s response to the various factors is extremely difficult as the understanding of the climate is very dynamic and nonlinear. The climate is committed with variability. The known natural factors that contribute to the climate change that includes the astronomical causes, the atmospheric causes, and the tectonic causes are proven factors as based on the historical event that caused a massive change in the Earth’s geological structure. The other factor considered as the human anthropogenic contributions to the global warming causing climate change is another field of discussion.
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