1The School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
2National Centre for Atmospheric Science, School of Environmental Sciences, Univ. of East Anglia, Norwich NR4 7TJ, UK
3UJF – Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE) UMR5183, Grenoble, 38041, France
4Grenoble Image Parole Signal Automatique (GIPSA-lab), Université Joseph Fourier/CNRS, BP 46, 38 402 Saint Martin d'Hères, France
5Max Planck Institute for Chemistry, Air Chemistry Division, Mainz, Germany
6Centre for Australian Weather and Climate Research, Commonwealth Scientific and Industrial Research Organisation, Aspendale, Victoria 3195, Australia
Abstract. Long term measurements in background air (Cape Grim, Tasmania) and firn air (NEEM, Greenland) of the potent long-lived greenhouse gas SF5CF3 show that emissions declined after the late 1990s, having grown since the 1950s, and became indistinguishable from zero after 2003. The timing of this decline suggests that emissions of this gas may have been related to the production of certain fluorochemicals; production of which have been recently phased out. An earlier observation of closely correlated atmospheric abundances of SF5CF3 and SF6 are shown here to have likely been purely coincidental, as their respective trends diverged after 2002. Due to its long lifetime (ca. 900 yr), atmospheric concentrations of SF5CF3 have not declined, and it is now well mixed between hemispheres, as is also shown here from interhemispheric aircraft measurements. Total cumulative emissions of SF5CF3 amount to around 5 kT.