evidence: However, human activity is resulting in the increased emission of so-called greenhouse gases (GHGs) which, unlike other atmospheric gases such as oxygen and nitrogen, becomes trapped in the atmosphere, unable to escape the planet. This energy returns to the surface, where it is reabsorbed. [...] Carbon dioxide (CO2), methane and nitrous oxide are the major GHGs to worry about. CO2 stays in the atmosphere for up to 1,000 years, methane for around a decade, and nitrous oxide for approximately 120 years. Measured over a 20-year period, methane is 80 times more potent than CO2 in causing global warming, while nitrous oxide is 280 times more potent.