All the gases except oxygen are responsible for global warming as they help in absorbing and holding heat in the atmosphere - a phenomenon known as the greenhouse effect.
The reason is discussed below.
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.normal greenhouse gases in Earth's atmosphere are water vapor,carbon dioxide,methane,nitrous oxide, and ozone.
oxygen (O2), is not greenhouse gas because molecules containing two atoms of the same element.
Such as O2 and mono atomic molecules (single atomic molecules)such as argon (Ar) have no net change in the distribution of their electrical charges,when they vibrate and hence are almost totally unaffected by infrared radiation. Although molecules containing two atoms of different elements such as carbon monoxide(CO)or hydrogen chloride(HCl) absorb infrared radiation, these molecules are short-lived in the atmosphere owing to their reactivity and solubility. Therefore, they do not contribute significantly to the greenhouse effect and usually are omitted when discussing greenhouse gases.