AbstractA column model coupling photochemistry and radiative transfer has been used to examine the relationship between carbon dioxide and ozone amounts in the stratosphere in a chlorine‐free atmosphere. The annually averaged ozone column density increases by about 10% as the CO2 volume mixing ratio is increased from 250 to 700ppmv. These increases result from cooling of the upper stratosphere by up to 20 K over this range. The phase of the seasonal variation of ozone in the upper stratosphere is correctly reproduced, with the annual maximum occurring at the time of minimum temperature rather than at the time of maximum insolatio