Greenhouse gases and recovery of the Earth’s ozone layer

Abstract

A numerical 2-D zonally averaged dynamical radiative-photochemical model of the ozonosphere including aerosol physics is used to examine the role of the greenhouse gases CO 2, CH 4, and N 2O in the recovery of the Earth’s ozone layer after reduction of anthropogenic discharges of chlorine and bromine compounds into the atmosphere. A weakness in efficiencies of all catalytic cycles of the ozone destruction due to cooling of the stratosphere caused by greenhouse gases is shown to be a dominant mechanism of the impact of the greenhouse gases on the ozone layer. Numerical experiments show that the total ozone changes caused by greenhouse gases will be comparable in absolute value with the changes due to chlorine and bromine species in the middle of the 21st century. Continuous anthropogenic growth of CO 2 will lead to a significantly faster recovery of the ozone layer. In this case, the global total ozone in the latitude range from 60°S to 60°N will reach its undisturbed level of 1980 by about 2040. If the CO 2 growth stops, the global total ozone will reach this level only by the end of the century.