What Are Greenhouse Gases?
The greenhouse effect is primarily natural, and is caused by a group of gases resident in the atmosphere that absorb and retain heat. The greenhouse effect is a phenomenon whereby there is a relatively thin envelope of gases in the lower atmosphere that act like a greenhouse does. A greenhouse glass cover lets in sunlight but blocks the escaping heat from leaving thus warming up the physical conditions of the enclosed space. This allows for the manual control of the weather in the greenhouse and so optimum environment for plant growth and crop production. In this case, greenhouse gases in the planetary atmosphere allow for incoming solar radiation to pass through the air and reach the earth’s surface. However, when this light hits the ground it is converted to infrared heat, and reflected back to outer space. But these gases absorb this heat, preventing it from escaping and warming up the entire planet. The earth from space - image credit (Visible earth/NASA)