Is the ozone "hole" shrinking at last?
As I pointed out recently, the ozone levels at Mauna Loa seem to be just oscillating across an an unchanging range, indicating no trend. And ozone is well mixed so at least that non-trend should also apply over the Antarctic. And that does seem to be so. The "hole" too just oscillates, expanding and contracting in a random way. And in October 2015 the Antarctic ozone hole reached a record size. No shrinking there! Which is very frustrating to Greenies.
But they were determined to find something to support their thinking so pulled together all the data they could find on the hole and tortured it with statistics. They did something that is totally illegitimate in statistics: Data dredging. If you look hard enough at any set if statistics you can generally find SOME trend or correlation somewhere. The problem is that extending the data base in some way usually wipes out the trend or correlation. There is a classic example of that here in a study of lynching in the American South.
So what did the authors dredge out? It would be funny if it were not so pathetic. They found a trend line going through the data for September only. In Septembers since 2000, the ozone has been behaving itself, too bad about the other months of the year. How you can draw any inferences from that -- let alone the sweeping inferences they do draw -- I do not know.
And why 2000? There's no theoretical reason. It's just more data dredging. It's also one of the classic tricks of chartmanship. If you are allowed to pick your starting and end points in a trend line, you can "prove" almost anything.
At the risk of beating a dead horse I will have one more laugh at these galoots. What do they say about the VERY embarrassing October 2015 ozone hole? They say the reading then was influenced by a volcano: "the Calbuco eruption" in Southern Chile. Being a suspicious soul, I looked up exactly when Calbuco erupted: April 2015! Something that happened in April had no effect until 6 months later! Pull the other one! One would expect a big effect immediately after the eruption, tapering off in subsequent months. Instead these Warmists ask us to believe the opposite happened. It's not even clever lying.
And, anyway, volcanoes are fairly common on a global scale and it is global ozone that is supposedly affected by wicked man-made chemicals -- so how come this eruption was so unusually significant? Was it vast? No. It was just a level 4 event (out of 10). Clearly blaming Calbuco is a work of desperation. The October 2015 ozone level was just another episode in the random walk that is the ozone "hole". The Greenies bullied us out of our best refrigerant gases for nothing.
And their crookedness and deceptions never stop
Emergence of healing in the Antarctic ozone layer
Susan Solomon et al.
Industrial chlorofluorocarbons that cause ozone depletion have been phased out under the Montreal Protocol. A chemically-driven increase in polar ozone (or “healing”) is expected in response to this historic agreement. Observations and model calculations taken together indicate that the onset of healing of Antarctic ozone loss has now emerged in September. Fingerprints of September healing since 2000 are identified through (i) increases in ozone column amounts, (ii) changes in the vertical profile of ozone concentration, and (iii) decreases in the areal extent of the ozone hole. Along with chemistry, dynamical and temperature changes contribute to the healing, but could represent feedbacks to chemistry. Volcanic eruptions episodically interfere with healing, particularly during 2015 (when a record October ozone hole occurred following the Calbuco eruption).
Science 30 Jun 2016: DOI: 10.1126/science.aae0061. See here for another summary of their findings