Paul A. Newman (USA) SAP co-chair NASA/GSFC Greenbelt, MD Primarily derived from WMO (2011) The Montreal Protocol and hydrochlorofluorocarbons (HCFCs) HFC Management Workshop Paris, July 2014 July 11, Workshop on HFC Management

Montreal Protocol signed Emissions CFC-11 equivalent Megatonnes/yr HCFC accelerated phase-out (Montreal – 2007 adjustment) Emissions of ozone depleting substances has declined under the Montreal Protocol July 11, Workshop on HFC Management

What are HCFCs? Hydroclorofluorocarbons (HCFCs) first appeared in the atmosphere in the 1960s to the 1980s. HCFCs were adopted as “interim” substitutes for CFCs following the Montreal Protocol. HCFCs are primarily destroyed in the troposphere by reaction with the OH molecule, and some small losses by reactions with oxygen atoms and sunlight. July 11, Workshop on HFC Management

Formula Lifetime (yr)ODP Radiative Efficiency 100-y GWP CFC-11CFCl HCFC-21CHCl 2 F HCFC-22CHClF HCFC-123CHCl 2 CF HCFC-124CHClFCF HCFC-141bCH 3 CCl 2 F HCFC-142bCH 3 CClF HCFC-225caCHCl 2 CF 2 CF HCFC-225cb CHClFCF 2 CClF HCFCs contribute to ozone depletion, and climate change HCFC-142b HCFC-22 HCFC-141b ppb 19.4 ppb 18.7 ppb Principal HCFCs Low ODPs w/r to CFC-11High GWPs July 11, Workshop on HFC Management

Emissions are expected to grow over the next decade, but will be phased out in response to Montreal (2007) HCFC emissions should soon begin to decline Growth of CFCs without MP HFC emissions are currently expected to substantially increase in the coming decades to replace HCFCs (see Dr. Ravishankara talk). July 11, Workshop on HFC Management

HCFCs contributed about 7.5% of the total chlorine to the stratosphere in 2008 Includes HCFC- 22, -141b, -142b, -124 July 11, Workshop on HFC Management

HCFCs continue to increase, but are projected to decrease starting in about 2030 July 11, Workshop on HFC Management The 2007 HCFC Amendment leads to a HCFC decrease that begins in the late 2020s Observations

HCFCs now comprise a considerable bank of ODSs and greenhouse gases July 11, Workshop on HFC Management

HCFC GWP weighted emissions grow in importance until about 2020 HCFCs are beginning to dominate GWP weighted emissions Total radiative forcing falls off after about 2020, consistent with the shorter lifetimes of HCFCs July 11, Workshop on HFC Management

Summary HCFCs are interim compounds that have served as replacements for CFCs HCFCs are weaker ODSs than CFCs, but still contribute a significant contribution to chlorine in the stratosphere. They are also significant GHGs HCFCs are still increasing in the atmosphere, but should stop increasing in the mid-to-late 2020s. The 2007 phase-out will successfully reduce HCFC emissions by –0.6–0.8 ODP-Mt - total –0.4–0.6 GtCO2-eq per year –The effective chlorine return to 1980 levels is earlier by 4-5 years. July 11, Workshop on HFC Management