Photograph posted online, 16 September 2015
UNEP has designated 16th September as International Day for the Preservation of the Ozone Layer, and 2015 marks the 30th anniversary of the British Antarctic Survey’s paper in Nature alerting the world to the ozone hole and the adoption of the Vienna Convention for the Protection of the Ozone Layer in 1985. The Vienna Convention was followed by the Montreal Protocol on Substances that Deplete the Ozone Layer in 1987.
Based on evidence suggesting that chlorofluorocarbons (CFCs) were contributing to stratospheric ozone depletion, countries party to the Montreal Protocol agreed to phase them out, leading to a 98% reduction of the historic baseline levels of the ozone-depleting substances produced and consumed globally.
The Vienna Convention and Montreal Protocol are major international environmental success stories. The Antarctic ozone hole has not yet completely closed, but the damage is expected to heal by the middle of the century, and a similar hole in the Arctic has been avoided.
The photograph shows knitted representations of the three main stratospheric ozone depletion equations: the breakdown of CFC-11 in sunlight releasing a chlorine atom, and the cycle of ozone destruction catalysed by this chlorine. It was released on Ozone Day 2015. The knitted representations are part of a work in progress.