The relatively pleasant average global temperature of 15 o C is a direct result of two factors. Firstly, visible light is converted to heat when solar radiation strikes Earth's surface. All planets have atmospheres but the specific mix of gases in earth's atmosphere is termed air . Concentrations of gases in dry air in the earth's atmosphere. Gases in green are greenhouse gases.
Heat energy is transferred through the atmosphere as water changes from one state to another.
Heat is absorbed in processes such as melting, sublimation, and evaporation. In contrast, heat is lost to the atmosphere during freezing, condensation, and precipitation. The presence of moisture in the atmosphere is measured by the humidity of the air. Air pressure decreases with altitude and results in temperature changes as descending air is compressed or rising air expands. The section on air pressure and condensation explains how such pressure changes can lead to condensation and cloud formation.