Accelerated increases observed for hydrochlorofluorocarbons since 2004 in the global atmosphere

Tropospheric accumulation rates of the three most abundant hydrochlorofluorocarbons (HCFCs) were up to two times faster during 2007 than measured in 2003–2004. Tropospheric chlorine from HCFCs increased at 10 pptCl/yr during 2006–2007, up from 6 pptCl/yr in 2003–2004, and offset declines in chlorine from other anthropogenic ozone‐depleting substances in 2007 by approximately one‐third. Derived global emissions for HCFCs increased by up to 60% since 2004, and, for HCFC‐142b, emissions during 2007 were two times larger than projected recently. Measured tropospheric distributions suggest a shift in HCFC emissions to lower latitudes of the Northern Hemisphere. These changes coincide with exponential increases in developing country production and consumption and decreases in other countries. When weighted by direct, 100‐yr global warming potentials, HCFC emissions in 2007 amounted to 0.78 GtCO 2 ‐equivalents, or 30% larger than the average during 2000–2004, and were approximately 2.6% of fossil‐fuel and cement related CO 2 emissions.