The primary greenhouse gases in Earth's atmosphere are water vapor (H. 2O), carbon dioxide (CO. 2), methane (CH. 4), nitrous oxide (N. 2O), and ozone (O3). The 'greenhouse effect' is the warming of climate that results when the atmosphere traps heat radiating from Earth toward space. Certain gases in the atmosphere resemble glass in a greenhouse, allowing sunlight to pass into the 'greenhouse,' but blocking Earth's heat from escaping into space.
