GAGE AGAGE MEASUREMENTS INDICATING REDUCTIONS IN GLOBAL EMISSIONS OF CCL3F AND CCL2F2 IN 1992-1994/

Global Atmospheric Gases Experiment/Advanced GAGE (GAGE/AGAGE) observa tions of CCl3F indicate that global concentrations of this compound re ached a maximum in 1993 and decayed slightly in 1994; CCl2F2 concentra tions increased approximately 7 ppt in both 1993 and 1994. The observa tions suggest that world emissions in these two years were smaller tha n industry production figures would suggest and have decreased faster than expected under the Montreal Protocol and its amendments. An analy sis of regional pollution events at the Mace Head site suggest that in dustry may be underestimating the decline of emissions in Europe. It i s argued, however, that the decline in European emissions is not biasi ng the background Mace Head measurements (or the GAGE global averages) . Combining the chlorofluorocarbon measurements, including CCl2FCClF2, with GAGE/AGAGE measured global decreases in CH3CCl3 and CCl4 after 1 992 and with Cape Grim archived air measurements of CHClF2, the measur ements suggest that anthropogenic atmospheric chlorine loading from th ese six gases maximized in 1992 at 2.95 +/- 0.04 ppb and that it had d ecreased by 0.02 +/- 0.01 ppb by the beginning of 1995.