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Amber McGraw American Intercontinental University Unit 1 Individual Project BUSN300-1005A-11: Lower Division Capstone November 11, 2010 Abstract The impacts of global warming vary depending upon perspective and in this paper I will discuss the debate of whether global warming is caused by human activity and carelessness or whether it is just a normal part of the Earth’s natural cyclical processes. Global Warming: Natural or Manmade?
Global Warming has been an intriguing and worrisome subject amongst environmentalists, scientists and society alike, especially in the last few decades, but is global warming a topic to raise concern or just a normal phase in the nature climate cycles of Earth. In order to determine who or what is to blame for the recent change in the Earth’s climate, we must first review the findings of both sides. We must take into account the normal cycles of climate change that our planet cyclically goes through as well as the abnormal changes that have taken place since the industrial period when the impact on the climate could be attributed to humans.
Scientists have been studying the climate trend on Earth for many years through the different cycles that occur here. One of the cycles is referred to as the hydrologic cycle, which is the process of Earth’s water constantly being cycled through reservoirs in the oceans, in the air and on the land (Egger, 2003). Scientists have found that the amount of water on Earth is constant and only changes or cycles during different climate periods. For instance, during warmer periods of climate change glaciers melt and in turn cause a rise in sea level, but the amount of water does not change.
The water is only cycled from a solid (glacier) to a liquid (water) and when the planet is in a cooler climate period, we see glaciers grow and sea levels drop. As the sea levels rise there is more water that can be warmed by the Sun and since water expands as it gets warmer, the sea levels will continue to rise. The increased speed of the hydrologic cycling can also be attributed as the cause for the more severe and more frequent occurrences of tropical storms since the temperatures are higher causing more water to evaporate which causes more precipitation (Egger, 2003).
If we take a look at the historical records of glaciers we will find that the hydrologic cycle effect has indeed taken place. There is evidence that over the last few centuries glaciers have melted, expanded and changed position on all continents due to the changing climate on Earth. When we review the observation history of the glaciers in the Arctic we will also find that 80% of them have lost mass since the Little Ice Age at a steady rate, but there is no evidence suggesting that the decrease in size has been exacerbated but the industrialization of the world (Avery ; Singer, 2005).
There is no data to suggest that during the carbon dioxide spike of the 21st century this process has been sped up by humans. The historical records of the Arctic glaciers explain that before the year 1200, the glaciers melted for a few centuries during a warming period referred to as the Medieval Warming, but then began to expand or grow in the 15th, 17th and late 19th centuries (Avery ; Singer, 2005). The changes in the size and mass of the world’s glaciers can also be attributed to the changes in the Earth’s circumnavigation around the sun causing cyclical changes on the planet.
There are cycles that cause alterations in the amount of solar radiation that reaches Earth and this cycling is referred to as the Milankovitch Cycles (Locke, 2010). The Milankovitch Cycles refer to the location of the solar energy and the reoccurring patterns of solar energy within a year’s time. According to the Milankovitch Cycle the first factor contributing to the Earth’s climate is the shape of the Earth’s orbit around the Sun which ranges from an elliptical shape to an almost perfect circle (Locke, 2010).
During the changes in orbit, the distance between the Earth and the Sun also changes. This change of distance alters the amount of solar energy that reaches the surface of our planet. The distance differentiation between when the Earth is at its most elliptical and less elliptical is a difference of almost 30%, which means that we are receiving 30% less radiation from the Sun at different points in time. This dramatic change takes place over thousands of years, but directly alters the glaciations and climates of our planet.
The other contributing factor correlated with the Earth’s orbit is the tilt of Earth on its axis. The less amount of tilt equates to a more even distribution of sunlight during the seasons, which also accounts for the large disproportion of light distribution between the Polar Regions and equatorial regions of Earth. When the winters on Earth are warmer, the air holds more moisture which causes more winter precipitation, but when the summers are cooler, the buildup accumulated by the winter weather has no way to melt, therefore causing an influx of glacial growth (Locke, 2010).
It is also important to consider the reflection of the Earth’s glacier’s when determining the change in global climate. When there are a larger number of glaciers or ice, more of the sunlight is reflected back into space which causes the air to cool and glaciers to grow. On a larger, cyclical scale, the effects on the solar energy or impact of the Earth are caused by changes that have taken place in the Sun. Taking a closer look at the changes occurring in the Sun, we can see that in the last century alone the magnetic flow of solar energy from the Sun has doubled.
Since the Sun’s magnetism is directly connected to the amount and strength of sunlight reaching the surface of our planet, this has caused our global climate to warm (Whitehouse, 2007). The Sun’s magnetic field is caused by the streams of solar energy or particles that fill the solar system and evidence shows that this magnetic field has strengthened by 40% since the 1960’s. When we compare this evidence to the magnetic field level prior to the space age, we see that the magnetic field is twice as strong as it was at the beginning of the 20th century (Whitehouse, 2007).
This increased solar activity occurs simultaneously with the amount of carbon dioxide in our atmosphere. Since the Sun produces a heightened level of solar energy it has caused the Earth’s global climate to become warmer, which warms the oceans as well. When the oceans are warmer, they are less able to adequately absorb carbon dioxide from the atmosphere, causing an increase in greenhouse gases. It is also historically documented that during the Little Ice Age the Sun had the appearance of less sunspots, but during the warmer period in the 12th century known as the Medieval Warming, the sun appeared brighter with more sunspots.
The change taking place on the Sun also correlates with the way in which the Earth’s orbit around the sun changes. The orbit around the Sun is cyclical, just as the climate is and the current orbit configuration of the Earth directly impacts the climate changes occurring on our planet. When you combine a changing orbit around the Sun, with a Sun that is getting hotter, the results will be a warmer planet. Years ago when the Earth’s orbit was more round and the Sun was cooler and farther away from the Earth, the climate of Earth was cooler and sea levels were lower.
Now that the orbit has changed and we are closer to a hotter Sun, the global ice is melting, sea levels are rising and the global climate is getting warmer. On the other side of the debate of global warming is the shift of blame onto the human race. While some scientists feel as though the changes in Earth’s climate are all derived from natural explanations, some scientists feel as though we are the reason for the change in global temperatures.
According to records, before the Industrial Revolution the amount of emitted carbon dioxide was balanced between large natural sources and what was absorbed during natural processes. The balance has now changed since then and according to scientists; humans are to account for putting more than twice as much carbon dioxide into the atmosphere (Mastrandrea & Schneider, 2007). The human activities that are said to contribute to global warming are the clearing of land, the increased burning of coal, oil and natural gas in cars, factories and power plants used to provide energy.
This constant burning of fossil fuels creates more greenhouse gas or carbon dioxide that causes a barrier preventing the heat created by the gases to escape. The current burning of fossil fuels is said to make up over 80% of the carbon dioxide being released into the atmosphere. Methane, nitrous oxide and chlorofluorocarbons are other forms of greenhouse gases that are said to be contributors to the rise in global warming and are attributed to the actions of humans by using these gases to operate pipelines, industry and griculture and are documented as being destructive to the stratospheric layer of the ozone. Plant life uses carbon dioxide to produce food, therefore taking the carbon dioxide out of the air, but since land is being cleared there is more carbon dioxide in the air with fewer trees to absorb the gas. Clearing of land also spreads the release of carbon dioxide by killing trees, causing them to prematurely decay (Mastrandrea & Schneider, 2007). Dead vegetation decomposes into carbon dioxide, in turn releasing it into the air.
If a tree were to die naturally, it would grow into another plant capable of producing oxygen and absorbing carbon dioxide and the emitted amount of carbon dioxide would be minimal. It is not debatable that the Earth has gone through many phases of warming and cooling during its existence, but the question that still remains is whether the changes that have been occurring during the last century and a half have been due to unnatural exposures. It has been a long running scientific debate on the cause of global warming and scientists from both sides seem to have their own proof to back up their claims.
It is safe to say that the two opposing viewpoints are well understood, but until further research is done and more historical records are interpreted accurately, the true cause of the rising temperature of our planet remains unknown. References: Egger, A. (2009). The Hydrologic Cycle: Water’s Journey Through Time. Retrieved 2003, from http://www. visionlearning. com/library/module_viewer. php? mid=99 Locke, W. (2010). Milankovitch Cycles and Glaciations. Retrieved from http://www. homepage. montana. edu/~geol445/hyperglac/time1/milankov. htm Mastrandrea, M. , ; Schneider, S. (2007).
Causes of Global Warming. Retrieved from NASA website: http://www. nasa. gov/worldbook/global_warming_worldbook. html Singer, S. , ; Avery, D. (2005). The Physical Evidence of Earth’s Unstoppable 1,500-Year Climate Cycle . Retrieved from http://www. ncpa. org/pub/st279/ United Nations Environment Program. (2006). Common Questions About Climate Change. Retrieved from U. S. Global Research Information Office website: http://www. gcrio. org/ipcc/qa/05. html Whitehouse, D. (2007). Global warming – Is the Sun to blame? Retrieved from http://news. bbc. co. uk/2/hi/science/nature/358953. stm