Still no time for complacency: evaluating the ongoing success and continued challenge of global ozone policy

This article concludes the special issue by outlining the most important indicators of the ozone regime’s success as well as issues that could slow or even prevent the complete restoration of the Earth’s protective “ozone layer” or lead to new causes of depletion in the future. Evidence for the ozone regime’s success includes the following: the declining production and consumption of ozone-depleting substance (ODS) chemicals; declining levels of ODS in the atmosphere; reduced depletion of stratospheric ozone; the projected recovery of the ozone layer during this century; reduced UV radiation and the associated environmental, human health, and economic benefits; universal participation in the regime’s treaties; the operation of regime institutions; and the regime’s ancillary success in reducing certain greenhouse gas emissions. Despite these historic successes, global ozone policy faces important challenges. These include the following: the millions of tons of ODS that remain in existing and discarded equipment and materials; the potential difficulty of completing the hydrochlorofluorocarbon (HCFC) phaseout; the broad exemptions that allow for the continued use of methyl bromide; the potential for illegal production and trade; the possibility that new ODS not covered by the regime have or will emerge; and the impacts of climate change. Copyright AESS 2015