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After reading this term paper you will learn about the composition of carbon cycle present in the atmosphere.
Carbon is found in various forms on the earth. It occurs in the elemental form as diamonds and graphite. In the combined state, it is found as carbon dioxide in the atmosphere, as carbonate and hydrogen carbonate salts in various minerals.
All life-forms are based on carbon-containing molecules like proteins, carbohydrates, fats, nucleic acids and vitamins. The endoskeletons and exoskeletons of various animals are also made of carbonate salts.
Cycle:
Carbon is incorporated into life-forms through the basic process of photosynthesis that is performed in the presence of sunlight by all life-forms that contain chlorophyll. This process converts carbon dioxide from the atmosphere or dissolved in water into glucose molecules.
These glucose molecules are either converted into other substances or used to provide energy for the synthesis of other biologically important molecules. The utilization of glucose for energy production in living things through respiration, which uses oxygen to convert glucose back into carbon dioxide. This carbon dioxide then goes back into the atmosphere.
Another process that adds to the carbon dioxide in the atmosphere is the process of combustion where fuels are burnt to provide energy for various needs like heating, cooking, transportation and industrial processes.
In fact, the percentage of carbon dioxide in the atmosphere is said to have doubled since the industrial revolution when human beings started burning fossil fuels on a very large scale. Carbon, like water, is thus cycled repeatedly through different forms by the various physical and biological activities.
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The Greenhouse Effect:
The greenhouse effect is a natural process that warms the earth’s surface. When the sun’s energy reaches the earth’s atmosphere, some of it is reflected back to space, and the rest is absorbed and radiated back by the greenhouse gases.
Greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone and some artificial chemicals such as chlorofluorocarbons (CFCs).
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The absorbed energy warms the atmosphere and the surface of the earth. This process maintains the earth’s temperature at around 33 degrees Celsius warmer than it would otherwise be, allowing life on earth to exist.
Enhanced Greenhouse Effect:
The problem we now face is that human activities – particularly burning fossil fuels (coal, oil and natural gas), agriculture and land clearing – are increasing the concentrations of the greenhouse gases. This is the enhanced greenhouse effect, which is contributing to warming of the earth.
