Greenhouse effect

Definition

Short-wave electromagnetic radiation from the Sun passes through the transparent atmosphere unhindered (except for the effect that albedo has on the mean reflectivity of a planet). On heating the planet's surface, long-wave radiation (i.e. Infrared radiation) is emitted into the atmosphere. Long-wave radiation will not escape into space if the atmosphere is dense enough, and contains greenhouse gases (such as carbon dioxide, water vapour, methane etc.) which reflect long-wave radiation back to the surface, heating the atmosphere further. This shortwave input, long-wave emission, long-wave reflection, atmospheric heating process is known as the Greenhouse Effect.

Terraforming Mars

The Greenhouse Effect is an essential process to heat a planet's atmosphere to habitable temperatures. To make life sustainable on the surface of Mars, the process of terraforming would require a thickening of the tenuous Martian atmosphere and injection of selected greenhouse gases.