Global Warming



Meghan McDonald McDonald 1
Mr.Hrkal
OAC World Issues
December 18th, 2000
Global Warming

Now, for the first time in Earth\'s history, humans may be a decisive factor in future climate change. The actions we make towards the temperature of the earth and the depletion of the ozone layer are irreversible. A warmer future could result from present-day human activities releasing large amounts of heat-trapping gases into the air. These "greenhouse gases" are part of the reason for the 1°F (.5°C) rise in global average temperature documented over the past 100 years. If the Earth\'s temperature continues to rise as predicted, future global warming could happen faster than any climate change of the last 10,000 years. If so, future variations in local climate could be even more disruptive than those of the past. Fossil fuels, which release carbon dioxide when burned, are used to generate electricity; heat and light homes and workplaces; power factories and run cars. Unless we reduce population growth and use of fossil fuels, the level of carbon dioxide in the atmosphere will double by sometime in the middle of the next century. The future of Earth\'s climate may depend partly on the buildup of heat-trapping gases, primarily carbon dioxide, methane, and nitrous oxide, in the atmosphere. Industrialized nations now release the most carbon dioxide. But how can this world wide disaster be stopped? To fully understand the magnitude of this problem, we must look at the causes

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of global warming, what is being done to stop the problem, consequences of this issue, and how we can prevent it.
What is Global Warming?
The depletion of the ozone layer and global warming are a result of the heat trapping abilities of “greenhouse gases”. The glass panels of a greenhouse and the Earth’s atmosphere are both transparent to sunlight, and both trap heat. Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse. Thus creating the greenhouse effect. At present, the Earth appears to be facing a rapid warming, which most scientists believe results, at least in part, from human activities. The chief cause of this warming is thought to be the burning of fossil fuels, such as coal, oil, and natural gas, which releases into the atmosphere carbon dioxide and other substances known as greenhouse gases. As the atmosphere becomes richer in these gases, it becomes a better insulator, retaining more of the heat provided to the planet by the Sun. Through years of abuse and neglect, the situation continues to worsen. Some may feel that Global warming is inevitable, and that the climate will change no matter what. This is partly true. Climate does change all the time, but it changes slowly. We are doing it at enormous speeds, 60 times faster than normal.


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Greenhouse Gases
All life on Earth relies on the greenhouse effect, without it, the planet would be colder by about 33-Celsius degrees, and ice would cover Earth from pole to pole. However, a growing excess of greenhouse gases in Earth\'s atmosphere threatens to head in the other direction, toward continual warming. Carbon dioxide is the most abundant greenhouse gas followed by methane and nitrous oxide. Carbon dioxide flows into the atmosphere from many natural processes, such as volcanic eruptions; the respiration of animals, which breathe in oxygen and exhale carbon dioxide; and the burning or decay of organic matter, such as plants. Humans escalate the amount of carbon dioxide released to the atmosphere when they burn fossil fuels, solid wastes, and wood products to heat buildings, drive vehicles, and generate electricity. At the same time, the number of trees available to absorb carbon dioxide through photosynthesis has been greatly reduced by deforestation, the long-term destruction of forests by indiscriminate cutting of trees for lumber or to clear land for agricultural activities. Methane is an even more effective insulator, trapping over 21 times more heat than does the same amount of carbon dioxide. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane also comes from rotting organic waste in landfills, and it is released from certain animals, especially cows, as a byproduct of digestion.