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Homework Help: Social Studies: World Issues: Ozone Depletion and Global Warming
by Ling Ling Lee Chow Chang Tsui Mitsubishi
Is our earth really getting warmer? Is the ozone layer really disappearing? These are some of the questions scientists are still working on answering. Global warming and ozone depletion are both very big problems that our world must deal with. Global Warming refers to the increase in the average temperature of earth. The Greenhouse Effect is the role that the atmosphere plays in insulating and warming earth's surface. Ozone depletion is the vanishing of our ozone layer, which protects earth from harmful UV rays.
Global warming is the increase in the average temperature of the atmosphere, oceans, and landmasses of earth. This increase in temperature is due to the greenhouse effect. The greenhouse effect is the term for the role the atmosphere plays in insulating and warming the earth's surface. The sun's energy lights and also heats the earth. Most of the energy from the sun is short wave radiation, including both visible and ultraviolet light. When this light hits the earth, earth's atoms absorb the energy and start to vibrate, this vibration makes infrared heat energy and warms the earth. Some of the sun's radiation is reflected back into space. Some of this reflected energy stays trapped in our atmosphere because of greenhouse gases. There are certain gases in our atmosphere that absorb and reflect this light; these gases include water vapor, carbon dioxide, and methane. These gases conserve heat just like the glass in a greenhouse does. Therefore they are called "greenhouse gases." Life on earth would be very different without the Greenhouse Effect. The greenhouse effect serves to keep the annual average temperature of the earth approximately 57¡F (32¡C). The amount of carbon dioxide in the atmosphere has increased by 28 percent over the past hundred years. Most scientists think this dramatic rise in carbon dioxide levels is due to the excessive burning of fossil fuels such as gas, oil, and coal. Some of the main CO2 producers are transportation vehicles, power plants, and industrial buildings. Since the beginning of the industrial revolution the methane levels in our atmosphere have increased by 100% and the nitrous oxide concentrations have risen about 15%. With all these extra gases, our atmosphere is able to trap more heat and thereby warm the earth. Methane traps 21 times more heat than carbon dioxide and nitrous oxide traps over 270 times carbon dioxide. Out of all these atmospheric gases some are natural and some are only there because of humans. The naturally occurring gases are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. While we are adding to the amount of these "naturally occurring gases," which is not necessarily good, they would be there even if humans did not interfere. One thing in our atmosphere that is not naturally occurring is chlorofluorocarbons, CFC's. If we keep adding all these gases to the atmosphere at the present rate the average temperature of the earth may rise between three and seven degrees Fahrenheit by the year 2030. Snow around earth's poles and icebergs are predicted to slowly melt because of the temperature increase. The sea level is expected to rise. Evaporation will increase and that will increase precipitation. Global warming also effects weather patterns. It is predicted that there will be an increase in flooding, storms and a lot of agricultural loss. Also plants and animals that can not adapt to new climate conditions will over time become extinct.
The ozone layer is a protective layer in the stratosphere that shields us from dangerous Ultraviolet (UV) rays. Ozone is a form of oxygen. An oxygen molecule consists of two oxygen atoms but an ozone molecule consists of three oxygen atoms. Only about 9 out of every million molecules in the ozone layer are actually ozone. Other substances in the ozone layer are carbon dioxide, nitrous oxide, water vapor, methane, etc. CFC's are a not naturally occurring substance in our atmosphere, they are used in refrigeration, foam production, and air conditioning. They were considered a miracle product until scientists found out that they were destroying our atmosphere by breaking down each ozone molecule. A CFC molecule consists of one oxygen atom and three chlorine atoms. When a ray of UV light hits this molecule it breaks it apart, releasing four separate atoms, one oxygen and three chlorine. When a chlorine atom collides with an ozone atom (O3) it sticks to one of the oxygen atoms of the O3 and they combine to make chlorine monoxide, which is one oxygen atom and one chlorine atom. Then the two other oxygen atoms from the same ozone molecule are released and form just another plain oxygen molecule. If a chlorine monoxide molecule collides with another chlorine monoxide molecule they will combine together to make one oxygen molecule and then the two chlorine atoms are then free to float around and destroy more ozone. Through this process more ozone is destroyed than can be created and the net effect is that the ozone is being depleted. An example of ozone depletion is the large ozone hole over Antarctica. During the Antarctic winter, an oval-shaped polar vortex is formed over the South Pole. The polar vortex winds bring a lot of ozone to the area. The vortex is extremely cold, with average temperatures of -80 degrees Celsius (-112 degrees Fahrenheit), and these cold conditions form large clouds of frozen water vapor in the atmosphere. The clouds in the extreme cold gradually absorb nitrogen oxide, which is stored in crystals inside of the clouds. When sunlight passes through the cloud the UV rays release the ozone destroying molecules inside the clouds and therefore a lot of ozone around this area is quickly destroyed. Since the ozone layer protects us from harmful UV rays, as it is being destroyed more UV light will be able to pass through it therefor there will be more skin cancer and cataracts, and may cause even more damage to the human body that we do not know about. The ozone layer also reflects some of the short wave and visible light from the sun back into space but with less ozone molecule to reflect the light more may pass through.
Some similarities between global warming and ozone depletion are that they both have to do with our ozone layer and atmosphere. Both of them are happening because humans put too many chemicals into our atmosphere and both of them have to do with the warming of the earth, and the sun's rays. A few of the differences between global warming and ozone depletion are that global warming has to do with the trapping of heat and warming earth causing dangerous climate change. On the contrary ozone depletion's effects have to do more with humans and bodily diseases, such as skin cancer, cataracts and possibly mutations.
We live on a planet that must be in balance, this balance depends on many factors, some of which are, the amount of sunlight the earth receives, the chemicals in our atmosphere and the average temperature of the earth. These factors can be changed by the way we live our lives, by the way we pollute our air, land, and water. One of the only things that naturally protects us from these factors is the ozone layer and we for decades have been destroying it. Only recently have we started research to preserve it. Although not all scientist agree on global warming, enough evidence exists to suggest that we must do something about this disaster. From my point of view I believe that global warming is real and the earth's temperature is slowly rising, also I do believe although it is controversial that the ozone layer is being destroyed because of man-made materials.
Homework Help: Social Studies: World Issues
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