A potent greenhouse gas identified in the atmosphere: SF5CF3

We detected a compound previously unreported in the atmosphere, trifluorome thyl sulfur pentafluoride (SF5CF3). Measurements of its infrared absorption cross section show SF5CF3 to have a radiative forcing of 0.57 watt per squ are meter per parts per billion. This is the largest radiative forcing, on a per molecule basis, of any gas found in the atmosphere to date. Antarctic firn measurements show it to have grown from near zero in the late 1960s t o about 0.12 part per trillion in 1999. It is presently growing by about 0. 008 part per trillion per year, or 6% per year. Stratospheric profiles of S F5CF3 suggest that it is long-Lived in the atmosphere (on the order of 1000 years).