The other gases, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6) account for less than 2%, but their total emissions are growing. These gases differ in terms of their warming effect and their longevity in the atmosphere. Apart from these six GHGs, there are several other atmospheric substances that lead to warming (e.g. chlorofluorocarbons or CFCs, and black carbon - see Box 3.14) or to cooling (e.g. sulphate aerosols).