greenhouse gas / gases

Gases in an atmosphere that absorb and emit radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The main greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. [...]Greenhouse gases greatly affect the temperature of the Earth; without them, Earth's surface would be on average about 33 °C (59 °F)[note 1] colder than at present. [...] The burning of fossil fuels since the beginning of the Industrial revolution has substantially increased the levels of carbon dioxide in the atmosphere. [...] Scientists who have elaborated on Arrhenius' theory of global warming are concerned that increasing concentrations of greenhouse gases in the atmosphere are causing an unprecedented rise in global temperatures, with potentially harmful consequences for the environment and human health. Source: Wikipedia