Bugsy,

I'll ask and report if I find out more.

Many years ago I attended a lecture by the late John Daly. In passing he talked about how the thinning of the ozone over the South Pole had been recognised back in the mid 1950s. At the time they noticed that the 'hole' seemed to be getting smaller each year (you can sort of see that in the graphs in the paper from Farmen that Don linked). His point was that they thought it as merely curious and something to be watched. These were the days before scientists had learned to parlay scientific ambiguity into a scare and finally into a career.

From the very outset, there were those who doubted the CFC link. However, there was no constituency who were sufficiently disadvantaged by the proposed bans to fight them - well apart from the general public who would be required to pay more the the same product. But as always, the general public's interests didn't get a look in.

So we have a ban which initially seemed to be working. But now the apparent repair is stalling. At the very least that provides support to those who see the thinning as a natural cyclic phenomena. As I recall, at the time of the ban, we were assured that the start of the repair would be obvious quite soon after 1996 when the developed world would cease all use of CFCs. Recall that there was concern in the NH countries about their athletes being fried at the Sydney Olympics. At the time they were assured that things would be on the repair by then. Now that things aren't working out as planned we're told that they always knew it'd take the better part of 50 years to resolve.

So would a Paris agreement be like the Montreal Protocol? Given the caveat that I doubt there will be a PAris agreement worth the name, if it did happen it would be very much like Montreal - hailed as victory for science, completely against the interests of the general public, and probably completely useless

Thanks, Don, for an illuminating article. It appears that we were duped by the scare-mongrels again, to interfere with legitimate business without just cause.
Since there is no science to show any measurable effect of human emissions on climate, we can only hope that the lie-fest in Paris is on course for the usual welcome failure.

Bugsy,

My correspondent replies to you statement, as follows:

'Yes, the charts didn't result from ozone measurements but were predicted transmission propagation direction guides as noted. And yes, they are generally affected by solar activity.
My understanding is that the mainstream view is that solar radiation selectively ionises the residual atmospheric gases in the (upper) ionosphere while the solar UV component operates in the lower "ozone layer" to ionise O2 and convert it to O3 (ozone). Solar radiation impacts are maximised across the tangential magnetic polar regions with ionisation results such as auroras and "radio transmission holes" whereas the mainstream view is that the solar impacts are maximised in the tropics and then circulate polewards.
Experience of variable radio transmission "holes" occurring preferentially around polar regions and associated with solar disruption episodes leads to the conclusion that the "hole in the ozone layer" story is effectively a re-definition of existing solar radiation-induced upper atmosphere ionisation events rather than a separate and different phenomenon.
While that is an opinion rather than measured information, recent variations in the "ozone hole" accord with the solar radiation hypothesis better than the "chlorofluorocarbon" hypothesis.'

We know from experiments that chlorine monoxide is formed in the upper atmosphere from the breakdown of CFCs.
We also know that chlorine monoxide catalytically destroys ozone.

So regardless of the trivialities of how much of the antarctic ozone hole is down to CFCs, and what "hole" even means, the Montreal Protocol was a good thing. It has greatly reduced damage to the ozone layer. And because CFCs have a very high global warming potential, it has given us more time to deal with climate change.

As with the ozone hole, some people obsess over the trivialities of global warming, using them as an excuse to do nothing while ignoring the actual effects.

So if a Paris agreement on climate change is a total success, it will be like the Montreal Protocol on CFCs in one very important way: a very long time after the success, many people with a very poor understanding of the subject will be claiming it was unnecessary.

That's a lot of words to say "I made it up", Don.

So credulous, opinion as fact. That's the modern world for ya.