In addition, analysis of ozone data indicated for the first time that there had been wintertime ozone losses over areas of the northern hemisphere. Although the cause was uncertain, there was a possibility that man-made compounds could be involved. Based on this new information, the Protocol was amended to require a total phaseout of CFCs and halons, as well as other ozone-depleting compounds. The most recent information shows ozone losses extending into spring and summer over mid-latitudes in both hemispheres. Although there are still some uncertainties, available data indicate that the losses are probably due to increasing concentrations of chlorine and bromine.
Negotiations are underway to accelerate the phaseout schedule for ozone-depleting substances.
Parties to the Protocol will meet in Copenhagen in November to finalize a new agreement. The information presented earlier in this seminar clearly indicates the potential for such effects and a sound basis for actions that have been taken. However, the great uncertainties in this area, and the poor prospects for resolving these uncertainties in the near future due to a continued lack of adequate funding for research, could pose a problem for future decisions as the character of the issue changes over the next decade. The potential for additional ozone depletion is likely to continue to increase for the next five to ten years. Due to the long atmospheric lifetimes and relatively recent start of large volume uses of most of the compounds involved, chlorine and bromine concentrations in the lower atmosphere will continue to increase until global consumption has been reduced to only 20 to 25 percent of the 1986 consumption rate.