VATIS UPDATE Article

In 2015, the south polar stratospheric vortex has been unusually large, strong and persistent with polar cap temperatures below the 1979–2014 average during most of July, August and September and with record low temperatures in October. The low temperatures, together with the size of the vortex, have led to the formation of an ozone hole that can be compared to the large ozone holes observed in 1998, 2000, 2003 and 2006.

Data on the ozone hole area from the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center showed that if averaged over the 60 worst consecutive days, 2015 has experienced the largest ozone hole ever seen. On the other hand, if one considers the amount of ozone destroyed, the so-called ozone mass deficit, the 2015 ozone hole is the fifth largest on record after 1998, 2000, 2001 and 2006.

As long as the amounts of chlorine and bromine in the atmosphere remain high, one can expect large ozone holes to occur if the stratospheric temperatures remain cold into the spring. According to the World Meteorological Organization (WMO)/United Nations Environment Programme (UNEP) Scientific Assessment of Ozone Depletion, a statistically significant decline is not expected in the size of the Antarctic ozone hole before 2025. In the meantime, large ozone holes are possible. In the long run, as chlorine and bromine decline, the annually recurring ozone holes will become increasingly smaller, eventually disappearing around 2070.