The Montreal Protocol on Substances that Deplete the Ozone Layer establishes the phase-out schedules for production and consumption of the most harmful ozone depleting substances (ODS). Different phase-out schedules apply to the industrialised and developing countries (Section 5.1). The ODS phase-out is in different stages of implementation across the globe. Eventually, production and consumption of ODS need to be phased out globally. Only then will the ozone layer be able to recover.
The present assessment deals with the results of previously undertaken investigations. These repeatedly give reasons for concern for potential effects, but relatively little progress has been made in quantifying these effects. The more the investigators look into the problems, the more the complexity becomes apparent. Nevertheless, the knowledge is accumulating