Global Warming: Natural or Man-Made?

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Global Warming: Natural or Man-Made?

Heather Waltman

SCI 207: Dependence of Man on the Environment

Instructor: Houtan Noushmehr

January 21,2013

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Global Warming: Natural or Man-Made?

There is no question that there is an increase in Earth's temperature and we are experiencing what is referred to as global warming. The Earth has experienced this many times in history on a much larger scale, but, humans did not exist (and would not have been able to exist) at the time. The questions now are whether human actions are accelerating the process of global warming and possibly decreasing Earth's future sustainability; and, if so, what, if anything, can we do to ensure that Earth will have the ability to sustain life for many many many future generations to come. Human activity has been linked to Earth's warming temperatures, rising seas, more intense storms, and a host of other environmental woes, because increases in greenhouse gas emissions into the atmosphere from the burning of fossil fuels and deforestation trap heat that would otherwise escape from Earth which results in global warming; however, global warming may just be caused by natural occurrences, such as cosmic rays, the sun, volcanic activity and the ocean.

The combustion of fossil fuels input enormous emissions of CO2 into the atmosphere causing the atmospheric CO2 levels to rise radically. The academic textbook, Contemporary Environmental Issues states, "CO2 is the principal gas contributing to the enhanced greenhouse effect...three main greenhouse gases, CO2, CH4, and N2O, are rising because of human activities such as the burning of coal, oil, and natural gas" (Turk & Bensel, 2011). Levels of greenhouse gases in the atmosphere have increased substantially through the industrial revolution. In particular, the concentration of carbon dioxide in the atmosphere has increased by

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roughly 35 percent since the start of the industrial revolution (Turk & Bensel, 2011). Carbon dioxide concentration has increased due to the use of fossil fuels in electricity generation, transportation, and industrial and household uses. Globally, over the past several decades, about 80 percent of human-induced carbon dioxide emissions came from the burning of fossil fuels (Turk & Bensel, 2011). These emissions are thickening the blanket of heat-trapping gases in Earth's atmosphere, causing surface temperatures to rise. Figure 1 shows increases in concentrations of these gases since 1750 are due to human activities in the industrial era.

Surely, there is a natural amount of carbon dioxide in the atmosphere that the carbon cycle moves around. This is enough, with the other greenhouse gases, to keep the earth warm. Burning fossil fuels releases carbon dioxide that has been out of the picture, buried underground, for millions of years. So this release increases the levels of carbon dioxide, thus, accelerating the global warming process.

Another human action, deforestation, is a huge contributor to the increase of greenhouse gases in the atmosphere causing global warming. Deforestation is a process of cutting and/or burning trees to make space for pastures or for industries and households of the ever-increasing human population. As noted by the authors of Contemporary Environmental Issues, "Trees, like all living organisms, are made mostly of carbon; when forests are burned to clear land, the carbon in the trees is released as CO2" (Turk & Bensel, 2011). There are various notions as to the rationale behind large-scale deforestation, such as, that forested land is not as economically viable as farmland. In addition, other causes include the need to increase land for settlements and

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urbanization, timber for industrial use and as fuel, extensive conversion into agricultural grounds, corruption and unequal distribution of wealth, cattle ranching, and experimentation with forestry. The logging and/or burning of trees for fuel and to create pasture and plantation lands has in turn created a monster in the form of depleting forest cover and is a major factor contributing to climate change and global warming.

Unquestionably, trees play a huge role in the carbon cycle. They convert the CO2 in the air to oxygen, through the process of photosynthesis, and in this way, they can be looked at as a natural regulator of the carbon dioxide; the more trees, the less carbon dioxide (and more oxygen) in the atmosphere. Since we live in an age where carbon dioxide is very abundant in the atmosphere, released through man-made inventions, such as cars, factories, and power plants, it is vital, more than ever, that trees fulfill their part in the environment and take some of the excess carbon dioxide out of the air. Unfortunately, deforestation is preventing this job to be fully accomplished, and with half of all the Earth's forests gone, and four million trees cut down each year just for paper use, the amount of carbon dioxide is rising. With more carbon dioxide in the atmosphere, more of the sun's radiation is being reflected back to earth, instead of space, and this is causing our average temperature to rise. In this way, deforestation is a major issue when it comes to global warming.

Certainly, human activities are considered to promote global warming through the significant increase of greenhouse gas emissions into the atmosphere; therefore, the human race needs to take action to slow down the global warming process. An article in EarthAction, "STABILISE OUR CLIMATE: STOP GLOBAL WARMING", stresses that, "To protect our

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climate we must phase out fossil fuels and preserve our forests...clean energy alternatives such as solar, wind, small-scale hydro, geothermal and biomass, and an increase in energy efficiency