Global Warming
It is described as "Theory that the average temprature of Earth is rising as a result of increased amounts of carbon dioxide in the atmosphere chiefly from the burning of fossil fuels and from other human activities."

Earth has warmed by about 1ºF over the past 100 years, and is slowly rising. A warmer Earth can lead to changes in rainfall patterns, a rise in sea level, and a wide variety of impacts on plants, wildlife, and humans.

Green House Gas Effect
The earth recieves most of it's energy, called radiation, from the sun. This energy is electromagnetic radiation in the visible spectrum, with small amounts of infared radiation and UV radiation. The solar energy has a very short wavelenght and passes through the atmosphere gases un affected to reach the earth's surface. The earth's surface absorbs the solar energy and releases it back to the atmosphere as infared radiation (IR), some of which goes back into space.

Some of the IR emitted by the Earth is absorbed by gases in the atmosphere that re-emit the energy as heat back toward the earth's surface. Three main gases in our atmosphere that contribute to the greenhouse effect are carbon dioxide, methane, and water. These gases absord the IR emitted by the Earth and re-radiate the energy as heat back towards the Earth, causeing a warming known as the Greenhouse affect. With increasing carbon dioxide emessions from humans, the greenhouse affect has become drastically exaggerated. This has caused a dangerous global warming process that is threatening our current environment by melting polar ice caps and raising sea levels around the globe.