Recent increases in global HFC‐23 emissions

Firn‐air and ambient air measurements of CHF3 (HFC‐23) from three excursions to Antarctica between 2001 and 2009 are used to construct a consistent Southern Hemisphere (SH) atmospheric history. The results show atmospheric mixing ratios of HFC‐23 continuing to increase through 2008. Mean global emissions derived from this data for 2006–2008 are 13.5 ± 2 Gg/yr (200 ± 30 × 1012 gCO2‐equivalent/yr, or MtCO2‐eq./yr), ∼50% higher than the 8.7 ± 1 Gg/yr (130 ± 15 MtCO2‐eq./yr) derived for the 1990s. HFC‐23 emissions arise primarily from over‐fluorination of chloroform during HCFC‐22 production. The recent global emission increases are attributed to rapidly increasing HCFC‐22 production in developing countries since reported HFC‐23 emissions from developed countries decreased over this period. The emissions inferred here for developing countries during 2006–2008 averaged 11 ± 2 Gg/yr HFC‐23 (160 ± 30 MtCO2‐eq./yr) and are larger than the ∼6 Gg/yr of HFC‐23 destroyed in United Nations Framework Convention on Climate Change Clean Development Mechanism projects during 2007 and 2008.