A model is presented in which transport rates through the lower stratosphere change in association with the height of the tropopause. The ozone distribution and column density are computed as the tropopause rises beyond its present position. Two distinct effects are noted. First, the total ozone content decreases by about 3% per kilometer rise of the tropopause from its present position. Second, there is a redistribution of ozone from statosphere to troposphere, which is quite gradual at first but suddenly becomes pronounced as the tropopause encroaches into the odd-oxygen production region. The first effect is of minor significance in the modern atmosphere where it is masked by other dynamical and chemical variations. But the second effect is potentially important, as it suggests an associated major difference in the biological environment of the distant past when the atmosphere was warmer and less rich in oxygen. ¿American Geophysical Union 1987