- Greenhouse effect naturally occurring phenomenon that is responsible for the heating of the Earth's surface and atmosphere. Carbon dioxide and methane are common as greenhouse gases. When sunlight reaches the outermost layer of the atmosphere, clouds and gases reflect about one-fourth of the incoming solar radiation and absorb some of it. Almost half of the incoming solar radiation falling on the surface of Earth heats it. A small proportion is reflected back. The Earth's surface reflects heat in the form of infrared radiations but part of this does not escape into space as atmospheric gases (carbon dioxide and methane) absorb a major fraction of it. The molecules of these gases radiate heat energy. A major part of it comes back to Earth's surface thus heating it up once again.
- Increase in the levels of greenhouse gases leads to global warming.