Sunday, July 13, 2008

Global Warming

Global Warming- (Random House Unabridged Dictionary.) An increase in the earth's average atmospheric temperature that causes corresponding changes in climate and that may result from the Greenhouse Effect. (Greenhouse Effect - The phenomenon whereby the earth's atmosphere traps solar radiation, caused by the presence in the atmosphere of gases such as carbon dioxide, water vapor, and methane that allow incoming sunlight to pass through but absorb heat radiated back from the earth's surface. When sunlight reaches the surface of the Earth, some of it is absorbed and warms the surface. Because the Earth's surface is much cooler than the sun, it radiates energy as much longer wavelengths than the sun does.) The Earth has experienced numerous episodes of global warming through its history, and currently appears to be undergoing such warming. The present warming is generally attribute to an increase in the greenhouse effects, brought about by increased levels of Greenhouse Gases, (Greenhouse Gases are the gases present in the earth's atmosphere, which reduce the loss of heat into space and therefore contribute to global temperatures through the greenhouse effects. These gases allow sunlight to enter the atmosphere freely. The gases naturally blanket the Earth and keep it about 33 degrees Celsius warmer than it would be without these gases in the atmosphere) largely due to the effects of human industry and agriculture. Expected long-term effects of current global warming are raising sea levels, flooding, melting of polar ice caps and glaciers, fluctuations in temperature and precipitation, more frequent and stronger El Niños and La Niñas, drought, heat waves, and forest fires.
Scientists have spent decades figuring out what is causing global warming. They have looked at the natural cycles and events, are known to influence climate but the amount and pattern of warming that has been measured cannot be explained by these factors alone. The only way to explain the pattern is to include the effect of greenhouse gases emitted by humans.

The main cause of Global Warming
One of the first things scientists learned is that there are several greenhouse gases responsible for warming, and humans emit them in a variety of ways. Most come from the combustion of fossil fuels in Cars, Factories and Electricity production. The gas responsible for the most warming is Carbon Dioxide, also called CO2. Other contributors include methane released from Landfills and Agriculture (esp. from the digestive systems of grazing animals), Nitrous Oxide from fertilizers, Gases used for Refrigeration and Industrial Processes, and the loss of forests that would otherwise store CO2.