Scientific Assessment of Ozone Depletion: 2014 is the quadrennial report of the Scientific Assessment Panel (SAP) of the Montreal Protocol on Substances that Deplete the Ozone Layer. The SAP assesses the state of the depletion of the ozone layer and relevant atmospheric science issues every four years and provides Parties to the Montreal Protocol with critical information as they undertake their ozone protection activities and address challenges under the Protocol. The report indicates that the ozone layer is showing the first signs of an upward ozone trend. Further, the ozone layer is on track to recovery to 1980 benchmark levels-the time before significant ozone layer depletion- by the middle of this century, thanks to concerted international action to phase out ODSs. Although over 2.2 million metric tonnes of ODSs have been phased out over time by the nations of the world under the provisions of the Montreal Protocol, 640,000 metric tonnes of HCFCs remain to be phased out. The assessment report projects that atmospheric ODS amounts will continue to decline through the 21st century, assuming continued compliance with the Montreal Protocol. Since ODSs are also potent global warming gases, the Protocol has significantly contributed to climate change mitigation, having averted more than 135 billion tonnes of carbon dioxide equivalent emissions.