Although carbon dioxide is a linear molecule it is still a greenhouse gas. Explain why that is.

A greenhouse gas is one which absorbs infrared radiation from the Earth and re-radiates it, increasing the surface temperature of the Earth. Normally these molecules are non-symmetrical such as triflurometane. This is not the case as carbon dioxide is a linear symmetrical molecule. However  in the case of carbon dioxide, it is made up of a single carbon atom covalently bonded by double bonds to 2 oxygen atoms. Carbon dioxide therefore is still able to absorb infrared radiation. It can do so because each carbon oxygen double bond can buy vibrate at a different time from the other, known as asymmetrical vibration. This asymmetrical vibration of the carbon oxygen double bonds is what allows carbon dioxide molecules to absorb infrared radiation and re-radiated back to Earth acting as a greenhouse gas.