Predicting the future development of stratospheric ozone is a complex problem involving many chemistry-climate interactions. Ideally coupled chemistry-general circulation models (CGCMs) would be used to perform many transient integrations of future climate to investigate the possible scenarios and uncertainties.

Several CGCMs have been developed over recent year to study this problem. The chemical schemes used can be categorized as either simple parameterisations or complex models. Simple schemes are computationally cheap, allowing many model integrations to be performed. They are usually not physically based, however, so their results must be taken with caution. More confidence may be had in complex models but they are costly to run which limits the number of simulations that may be performed.

FASTOC (FAst STratospheric Ozone Chemistry) is a computationally efficient input-output chemical model that has been coupled to the Reading Intermediate General Circulation Model to study the future development of stratospheric ozone. Details of the method and early results are shown.