If this natural filtering process is unbalanced, the atmosphere will receive too much carbon dioxide and other greenhouse gases. Once these gases form in the atmosphere, they act as barriers trapping in heat and warming the earth. This process is not new. In fact, without the greenhouse effect, the average surface temperature of the earth would be about 59 Fahrenheit degrees lower than it is today. The greenhouse effect received its name because the atmosphere of the earth acts much like the glass roof on a greenhouse.
Sunlight enters the greenhouse through the glass as it heats up the plants.
Then, the warmth is trapped as the glass slows the withdraw of heat. Similarly, the earth's atmosphere lets most of the sun's light enter and heat the surface. This is when the actual effect takes place. Not all of the Infrared Radiation is sent freely into space. Certain gases in the atmosphere absorb it and send it back toward earth.