Past and future stratospheric ozone in a changing climate 

Prof. Dr.Ulrike Langematz, Institut für Meteorologie, Freie Universität Berlin 

 

With continuously increasing concentrations of manmade ozone depleting substances (ODSs), 
primarily halogens, since the 1970s, stratospheric ozone declined significantly until the end of the 
20th century. However, as a result of the Montreal Protocol on Substances that Deplete the Ozone 
Layer and its subsequent amendments and adjustments that constrained the production and 
consumption of halocarbons, the decline of stratospheric ozone has ceased. Model projections 
suggest a future recovery of the global mean ozone column to levels around the year 1980, when 
only low ODS levels existed in the stratosphere. However, the timing of the return of ozone to 
historical levels depends not only on the concentrations of ODSs but is also affected by thermal and 
dynamical changes associated with increasing greenhouse gas concentrations. For example, while the 
amounts of ODSs steadily decrease in the stratosphere, with appropriate meteorological conditions 
and given the long lifetimes of ODSs, individual years with strong ozone decrease may occur in the 
near future. 

Here, an overview of projections of the ozone layer based on EMAC chemistry-climate model 
simulations will be presented. The impact of climate change on stratospheric ozone recovery and the 
potential for future Arctic ‘ozone holes’ will be discussed.