The Montreal Protocol was accepted almost universally and successfully gained global cooperation to reduce the production and release of Ozone Depleting Substances (ODS). When Chlorofluorocarbons (CFCs) are released the free chlorine molecules that become available in the atmosphere are able to deplete the O₃ ozone molecule in a catalytic reaction allowing Ultraviolet (UV-B) radiation to enter the atmosphere. This deletion of the ozone layer was quickly acknowledged to be detrimental to human health and measures were taken. There is some concern that there are ODSs still being released from some sources and that there are residual ODSs in equipment yet to deteriorate. This review examines the present measurements of the ozone levels in the Antarctic stratosphere, how the increased use of modelling has improved the accuracy of the measurements and led to a clearer understanding of the dynamic mechanisms that reform the ozone hole each year. The polar vortex formation and the dynamically induced changes in the troposphere are the main drivers in the appearance of the ozone hole each year above the Antarctic. Mt Erebus has recently been found to be a significant source of ozone destroying gases. As these dynamic systems are more clearly understood and accounted for the variable annular ozone levels are able to be accurately assessed for the possible future recovery of the ozone hole to pre-1980 levels.