STRATOSPHERE: PRESENT AND FUTURE.

The document assesses those aspects of our current knowledge that pertain to the modification of the stratosphere by anthropogenic activities which lead to the release of halocarbons, nitrous and nitric oxide, carbon dioxide, etc. Naturally occurring perturbations such as related to solar or volcanic activity are likewise considered. The basis of model description is given in terms of the laboratory data for rates and cross sections and the types of models suitable for various purposes. Observed distributions of various trace species are considered in terms of their sources and removal mechanisms and are compared to values from models. Stratospheric meteorology is discussed in terms of the effects of dynamics on the distribution of species. Model predictions of ozone depletion are given for various scenarios; the accuracy to which such changes in ozone content may be detected in available observational data is discussed.