greenhouse effect
n.
A phenomenon in which the atmosphere of a planet traps radiation emitted by its sun, caused by gases such as carbon dioxide, water vapor, and methane that allow incoming sunlight to pass through but retain heat radiated back from the planet's surface.
greenhouse effectEnergy radiated by the sun converts to heat when it reaches the earth. Some heat is reflected back through the atmosphere, while some is absorbed by atmospheric gases and radiated back to the earth.