Old timers will remember sci.environment back in the days when it was all strat and polar ozone. A rather simple tweet from Judith Curry today
A Reagan approach to climate change - by George Schulz http://t.co/rGeGAJevaeand a reply from Turcano
— Judith Curry (@curryja) March 14, 2015
@curryja How did that "insurance" work out? The so called ozone hole continues to expand and contract quasi-periodically as before treaty.brought Eli back to days of yesteryear, so he went and looked at the latest data on the area of the Antarctic ozone hole
— Tucano Blogger (@Tucano238) March 14, 2015
A minor historical note. Gavin and Tim Osborne had a side discussion about whether this was absolute or an anomaly. It is absolute. The first TOMS was launched in late 1978. The ozone hole was first noticed from ground observations in 1984 by Farman, Gardiner and Shanklin of the British Antarctic Survey, at which point the TOMS team went back and looked at the data from 1979 on. As can be seen in the figure, the first three years, 1979, 1980 and 1981 are pretty consistent, it is only in 1982 that the hole appears for the first time.
The ozone column depth shows the same story. As Tim Osborne points out, this leads to the definition of a "normal" Antarctic Spring ozone column being 220 DU (
Eli, being Eli, pointed out that this meant that the Montreal Protocol Insurance Co. was doing a fine job.
Well, in for a penny and in for a pound, so the Bunny also went and read parts of the 2014 Scientific Assessment of Ozone Depletion and it appears that the overall decline in stratospheric ozone has also been arrested. While it is not quite ironclad, it sure looks like the recovery has begun, and the year when the healing begun was also roughly 1997, as with the Antarctic ozone hole