most abundant gas on earth
Water vapor is the most abundant green house gas but it is the most ineffective at holding heat. CO2 is the second most abundant and is relatively good at holding heat but not as good as methane but methane is only present in trace amounts and is not increasing in amount as greatly as CO2.
Answer: The answer depends on the region of the atmosphere and other factors, since the chemical composition of the Earth's atmosphere depends on temperature, altitude, and proximity to water. Usually, the 4 most abundant gases are: 1  nitrogen (N 2) - 78.084%. 2  oxygen (O 2) - 20.9476%. 3  argon (Ar) - 0.934%.