A model for estimating future emissions of sulfur hexafluoride and perfluorocarbons

Sulfur hexafluoride (SF6), perfluoromethane (CF4) and perfluoroethane (C2F6 ) are strong greenhouse gases with long (> 1000 year) atmospheric residence times. We derive emission factors for the major anthropogenic sources and project future emissions for 5 regions and the world. Although firms in man y industrialized countries are already limiting emissions, without further policy intervention global emissions will rise 150% (CF4 and C2F6) and 210% (SF6) between 1990 and 2050; radiative forcing will increase 0.026 W m(-2) . Full application of available low-cost and costless policies in industria lized nations would cut that radiative forcing by one-quarter. Increased fo rcing due to these gases is small (< 2%) relative to other gases but perman ent on the timescale of human civilization. We also quantify plausible mani pulations to governmental data that will be used to determine compliance wi th the 1997 Kyoto Protocol, which includes commitments for industrialized c ountries to regulate these and other greenhouse gases. More complete and tr ansparent data are urgently needed. West European nations, for example, can `cut' their emissions of these gases by half by 2010 simply by manipulatin g emission factors within the current bounds of uncertainty.