It has been suggested (Hudson,<1977>) that monitoring O3 levels in the upper stratosphere may provide an early warning signal for detection of changes in ozone owing to the effects of increasing chlorine burden. Penner and Chang <1978> suggested that the possible influence of changing solar UV flux may hinder this effort. Their study is extended here to investigate whether measurement of other trace species may yield more definitive information. Present study suggests that the long-term trend in upper stratospheric N2O may provide more suitable data, though indirect, on the supposed solar UV variations, hence better quantification of one potential mechanism of long-term natural variations in ozone.