Global Warming and the Greenhouse Effect

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Global Warming is due to the greenhouse effect. The greenhouse effect is a naturally occurring process that aids in heating the Earth's surface and atmosphere. It results from the fact that certain atmospheric gases, such as carbon dioxide, water vapor, and methane, are able to change the energy balance of the planet by being able to absorb longwave radiation from the Earth's surface. Without the greenhouse effect, life on this planet would probably not exist as the average temperature of the Earth would be a chilly -18 degrees Celsius, rather than the present 15 degrees Celsius. As energy from the sun passes through the atmosphere a number of things take place. A portion of the energy (26 % globally) is reflected back to space by clouds and particles. About 19 % of the energy available is absorbed by clouds, gases (like ozone), and particles in the atmosphere. Of the remaining 55 % of the solar energy passing through the Earth's atmosphere, 4 % is reflected from the surface back to space. On average about 51 % of the sun's radiation reaches the surface. This energy is then used in number of processes including: the heating of the ground surface; the melting of ice and snow and the evaporation of water; and plant photosynthesis. The heating of the ground by sunlight causes the Earth's surface to become a radiator of energy in the longwave band (sometimes called infrared radiation). This emission of energy is generally directed to space. However, only a small portion of this energy actually makes it back to space. A few naturally occurring atmospheric gases known as the greenhouse gases absorb the majority of the outgoing infrared ... ... middle of paper ... ...ons of ozone gas are found in two different regions of the Earth's atmosphere. The majority of the ozone (about 97 %) found in the atmosphere is concentrated in the stratosphere at an altitude of 15 to 55 kilometers above the Earth's surface. In recent years, the concentration of the stratospheric ozone has been decreasing because of the build-up of chlorofluorocarbons in the atmosphere. Since the late 1970s, scientists have discovered that total column ozone amounts over Antarctica in the springtime have decreased by as much as 70 %. Satellite measurements have indicated that the zone from 65 degrees North to 65 degrees South latitude has had a 3 % decrease in stratospheric ozone since 1978. Ozone is also highly concentrated at the Earth's surface. Most of this ozone is created as a by-product of photochemical smog.
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