According to the Intergovernmental Panel on Climate Change, SF6 is the most potent greenhouse gas that has been evaluated, with a global warming potential of 23,900 times that of CO2 when compared over a 100-year period. Sulfur hexafluoride is inert in the troposphere and stratosphere and is extremely long-lived, with an estimated atmospheric lifetime of 800–3,200 years.
Measurements of SF6 show that its global average mixing ratio has increased from a steady base of about 54 parts per quadrillion prior to industrialization, to over 10 parts per trillion (ppt) as of April 2020, and is increasing by about 0.35 ppt (3.5 percent) per year. Average global SF6 concentrations increased by about seven percent per year during the 1980s and 1990s, mostly as the result of its use in magnesium production, and by electrical utilities and electronics manufacturers. Given the small amounts of SF6 released compared to carbon dioxide, its overall individual contribution to global warming is estimated to be less than 0.2 percent, however the collective contribution of it and similar man-made halogenated gases has reached about 10 percent as of year 2020. Alternatives are being tested.
