Maybe it is because the major catalyst isn’t CFC’s after all? See this story:
Galactic Cosmic Rays May Be Responsible For The Antarctic Ozone Hole
In the conclusions of the paper here (PDF) there is this:
Thus, the above facts (1)–(5) force one to conclude that the CR[Cosmic Ray]-driven electron-induced reaction is the dominant mechanism for causing the polar O3 hole.
From NOAA’s Earth Systems Research Laboratory:
Antarctic Ozone Hole Persists, At Least for Awhile
Major success in reducing ozone-depleting substances may not pay off in the Antarctic for several more years
August in Antarctica means the Sun starts rising over the horizon again, following four months of darkness. For NOAA Corps officer Nick Morgan (GMD), stationed at the South Pole, the month also marks the moment when he begins measuring ozone in earnest.
For most of the year, Morgan and his colleagues launch giant plastic balloons into the air about weekly. Tethered to the balloons are instruments that take ozone readings up to about 18 miles high.
Then, in the Antarctic spring (August through October), sunlight-sparked chemical reactions begin eating away at ozone. Scientists start making measurements more often, and by October, Morgan or his colleagues are outside in minus 80°F temperatures about every other day. Morgan and other scientists around the world are watching those data carefully, looking for evidence that the Antarctic ozone hole is beginning to heal after decades of hurt.
There’s scant evidence yet, from the balloon-borne instrumnets or others on the ground and on satellites: At the end of September, total ozone was at its annual low of 122 Dobson units. Typical fall, winter, and summertime levels are 250-300 Dobson units. The worst-of-the-year ozone levels have averaged 108 during the last 24 years.
It will be difficult to establish a clear-cut recovery trend in Antarctic ozone levels because seasonal cycles and other variable natural factors—from the temperature of the atmosphere to the stability of atmospheric layers—can make ozone levels dip and soar from one day to another, says NOAA ESRL scientist Bryan Johnson. But the time is coming, probably within a few decades, when ozone depletion will no longer be observed each spring, Johnson said.
“And within the next decade or so,” Johnson says, “observations are anticipated to begin showing reduced severity of the ozone hole.”
As soon as the Sun crosses the horizon again during the Antarctic spring, sunlight-triggered chemical reactions involving air pollutants begin destroying ozone in a region of the atmosphere called the stratosphere. The stratospheric ozone layer protects Earth from some damaging ultraviolet radiation, so an ozone hole means more of that radiation can hit the surface and trigger elevated rates of skin cancer and crop damage.
In the Antarctic, the ingredients for ozone depletion line up perfectly around September: Sunlight, low temperatures in the stratosphere, polar stratospheric clouds that help catalyze the destructive chemistry, and the continued presence of ozone-depleting chemicals, many of them released decades ago. Most years, those conditions ease by early December, and the hole closes.
“The ozone hole has taken somewhat of a back seat in the public eye,” Morgan wrote in a recent blog post from the South Pole. “And maybe that is a sign of success.”
Levels of most ozone-depleting substances in the atmosphere have declined significantly since the 1987 Montreal Protocol was signed, he noted.
That international treaty initiated the phasing out of chemicals called chlorofluorocarbons (CFCs), then used widely in refrigeration, as solvents, and in aerosol spray cans. The chemicals were breaking down in the stratosphere, and reactive parts—chlorine and bromine atoms—triggered ozone destruction, when conditions are ripe (sunlight, polar stratospheric clouds, cold temperatures).
International scientists contributing to the quadrennial 2010 Ozone Assessment— including many NOAA scientists—have calculated that although global stratospheric ozone may recover by midcentury, the ozone hole in the Antarctic will likely persist longer.
More: http://esrl.noaa.gov/gmd/dv/spo_oz/ and http://icestories.exploratorium.edu/dispatches/south-pole-ozonesonde-lau… (video).
As for the quote in Edouard (11/13 6:52am) from Greenpeace:
“God created 91 chemical elements, man more than a thousand and the devil created one: chlorine.
Greenpeace magazine (Belgium), August 1992.”
I’d take that with a grain of salt.
As has been pointed out the cited article DOES NOT suggest that CFCs don’t cause the ozone hole. CFCs when exposed to radiation under the right conditions produce halide radicals in the upper atmosphere, and it is these that cause the destruction by catalysing the conversion of ozone into oxygen.
The radiation which does this job of releasing radicals from CFCs is for the most part sublight, which is why the reaction happens mostly in the spring when sunlight first reappears in the antarctic. The CFCs themselves cause no damage in the absence of radiation to split off halide radicals.
The paper suggests that ionising radiation (i.e. cosmic rays) might be implicated in this part of the process. If this is correct (which I doubt – call me a skeptic) then it simply adjusts our understanding of one minor aspect of the process by which CFCs destroy ozone in the upper atmosphere. The implication would be that the rate of the reaction would then be influenced by solar weather (sunspot activity etc).
The article does NOT suggests that the ozone hole is a natural phenomenon. It does NOT say that CFCs are not to blame.
Anthony – I have seen some odd recent activity in this article. A preamble appeared briefly acknowledging that this old article was misleading and stating that it was being reopened for comments. Then the preamble disappeared and all the old comments now appear to be new comments … ? Could you please check that the article appears now as you want it to be. I now see what looks like a direct copy of the original, which I don’t think you really want as the article isn’t your best work. I can’t imagine you would want to emphasize it in this way.
Could we please have a few more articles on the ozone hole in future. I think people here could stand to be a lot better informed as to the distinction between the ozone hole issue and the global warming issue. Something like 90% of the population (spurious made up percentage warning) thinks these two things are related. In fact they are completely separate problems.
From my point of view the actions taken to eliminate CFCs are an environmental success story.
Good science must explain what we observe.
Maximovich is on the money when he says:
Downward transport in the dark polar winter can lead to significant enhancements of NOx in the stratosphere. Because NOx can catalytically destroy ozone, such NOx enhancements lead to ozone depletion in the upper stratosphere as has been shown e.g. by Callis et al. (1998); Brasseur and Solomon (2005); Jackman et al. (2008); Baumgaertner et al. (2009).
Look for yourself to see where the ozone is currently located here: http://www.cpc.noaa.gov/products/stratosphere/strat_a_f/
Go to the lowest table.
The flux in ozone levels as the vortex waxes and wanes with day by day change in surface atmospheric pressure can be inferred here: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.aao.shtml
You will notice that when the AAO rises (indicating a fall in sea level pressure and a collapse in downward transport of NOx from the mesosphere) the atmospheric column is cold. But as soon as the AAO begins to fall (pressure begins to increase and the vertical transport begins anew, geopotential heights increase indicating a warming atmosphere as the ozone that has built up in the upper stratosphere/ margins of the mesosphere during the weak phase is conveyed to the altitudes that we monitor where it absorbs long wave radiation from the Earth and warms the local atmosphere. The location of areas of enhanced ozone is in the mixing zone, outside the margins of the zone of most active downward transport (where there is a complete absence of ozone and it is very cold) and can be seen in the act of descent at 10hPa here: http://www.cpc.noaa.gov/products/intraseasonal/temp10anim.shtml
and at 30hPa here:http://www.cpc.ncep.noaa.gov/products/intraseasonal/temp30anim.shtml
and at 200hpa (troposphere) here: http://www.cpc.ncep.noaa.gov/products/intraseasonal/z200anim.shtml
Where it seems to persist outside the margins of the semi permanent high pressure cells of descending air that form over the oceans. So, the troposphere at this level is almost a mirror image of what is in the stratosphere. It could be that upper atmosphere water vapour in the overturning atmosphere represented by these high pressure cells simply absorbs ozone (that is highly soluble in water).
Warming and cooling in the upper troposphere affects ice cloud density which determines the flux of solar radiation to the surface. So, we should take a strong interest in the flux in polar atmospheric pressure.
But, the most interesting thing that can be observed is that when the AAO rises (polar atmospheric pressure falls) the south east trade winds accelerate and the tropical ocean cools via enhanced evaporation.
And that is the source of the current La Nina, and all the other La Nina’s that have ever occurred in the past.
When the atmosphere is drawn away from the pole it goes to lower latitudes where it increases the pressure differential driving the trades.
But the trades are not the only winds affected. The westerlies and the polar easterlies also change in strength and region of influence as the balance in atmospheric pressure is altered. The strengthening of atmospheric pressure over the Arctic since 1997 (falling Arctic Oscillation Index) is driving down winter temperatures over land in the northern hemisphere as the cold polar easterlies invade territory that has been the province of the warm moist westerlies for the last thirty years.
Change in the AAO and the AO is most vigorous in winter when surface atmospheric pressure at high latitudes is highest. More atmosphere can be pulled away when there is more atmosphere to be pulled away.
It can be observed that the AO and the AAO indexes fall (rising pressure at the poles) when the Dst (disturbed time index that measure the strength of the ring current in the ionosphere, and is a measure of geomagnetic activity due to the solar wind) relaxes (becomes less negative).
That the atmosphere behaves in this way suggests that its capacity to change under the influence of electromagnetic forces has been generally underrated.
Where is Leif Svalgaard when you need him? It isn’t TSI that drives surface temperature but the solar wind. Who would have thunk it?
The natural “ozone killers” can be found here:
http://www.uni-heidelberg.de/presse/ruca/ruca2_2002/keppler.html
Also available in english without pictures: http://www.uni-heidelberg.de/press/news/press206_e.html
“Much less widely known is the fact that nature also produces substances that do precisely the same thing. Scientists have already identified over 3,500 natural ozone killers produced by bacteria, algae, fungi, lichens and insects. Together they are to blame for about 30% of the depletion of the ozone layer. The odd thing is that the sources detected so far are insufficient to explain the concentrations of natural ozone-hostile substances actually measured in the atmosphere.”
Ian H says:
Also the above article does not suggest that CFCs did and do not cause at least in part the ozone hole over the entire air column over the Antarctic Continent. As a layperson, I thought it is a good idea for other laypeople to read the basics about ozone depletion(just like myself). One significant conclusion there at Wiki is:
…which is well in line with the link about ozone depletion basics another commenter suggested: http://www.appinsys.com/GlobalWarming/Ozone.htm
Btw, as I understand it, when talking about ozone depletion outside polar regions, we understand the protective stratospheric ozone layer, never mind higher tropospheric ozone concentrations over some continents and islands (Australia? New Zealand?).
Ian H says:
I completely disagree for at least three (3) reasons:
(1)”More recently, policy experts have advocated for efforts to link ozone protection efforts to climate protection efforts.[44] [45]Many ODS are also greenhouse gasses, some significantly more powerful agents of radiative forcing than carbon dioxide over the short and medium term. Policy decisions in one arena affect the costs and effectiveness of environmental improvements in the other.” (Wikipedia)
(2) journalofcosmology.com/QingBinLu
The above paper claims to give answers to three puzzling questions:
First, how could CO2 and other non-CFC greenhouse gases play a negligible role in the 1950-2000 global warming in spite of their extremely high concentrations? Second, is there other evidence from satellite or ground measurements for the almost zero warming effect of increasing CO2?
Third, can the greenhouse effect of CFCs be large enough to account for the rise of 0.5~0.6 K in global temperature since 1950? This paper will address all the three questions.
(3)
And what is supposed to be one of the “proofs” that climate models get it right? Stratospheric cooling! Yes, but to what extent by ozone depletion and to what extent by greenhouse gases? The question remains up until now.
Completely seperate problems? I guess you have discovered by now that this is nonsense. Bottom line: This is a very informative article and comments threat. Although it takes a long time to separate the wheat from the chaff. The positive effect of the Montreal Protocol may very well be overstated and the cost too high. And yes, AGW proponents nowadays may well wish that these were two completely separate problems…
Patrick Davis says:
November 12, 2010 at 7:42 am
Well, back in the ’80′s the hole over the Antarctic was attributed to CFC’s released in the NH. I don’t see how CFC’s are, somehow, magigically attracted to Antarctic pole.
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You don’t see CFC’s magically attracted to the south pole; because they are not magically or otherwise attracted to the south pole. CFC’s are distributed uniformly around the globe. The conditions at the south pole are different than else where.
Anthony says
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Maybe it is because the major catalyst isn’t CFC’s after all?
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Er no! Thus comes from skimming the paper and not reading it properly.
I to skimmed it but got a better sense of what it was about.
CFC’s are still the culprit in this paper. This paper is speculating about an alternative way of breaking CFC’s down to make chlorine atoms. The chlorine atoms destroy ozone.
So sorry; this paper is not discrediting the Montreal protocol, and it’s not discrediting the scientists who discovered the ozone hole.
While I’m not going to go into the CFC debate, if you want some anecdotal evidence on sun from someone living in NZ, I can give it to you. When I was a kid in the 70s the highest SPF sold was 15 and that was considered a total block. It wasn’t a big deal if you forgot to put it on and it wasn’t waterproof so it washed off at the beach anyway. Result – a few mild sunburns but nothing needing medication, just a bit of discomfort in a hot shower. From the 80s onwards it got quickly and steadily worse. The SPF’s shot up to 50, and we started getting told to put on a shirt, sunscreen, hat and sunglasses (slip, slop, slap & wrap is the slogan). Today it’s quite easy to get bad sunburn in winter, and during summer you can get a bad sunburn with under 10 mins exposure unprotected. Bad being “Holy crap, I need painkillers”. An hour can send you to hospital. Having travelled around the world, there is a very noticable difference in the way the sun feels on your skin. In NZ it can be a very mild day but if you step from the shade into the sun it feels like the temp went up several degrees. There is a noticable burning sensation on a hot summers day. Travel to the northern hemisphere and you get a far gentler heat sensation when you’re in full sunlight. 2 years ago I sat on a beach in Thailand under an umbrella with sunscreen all day and did not get sunburned. I have done the same thing in NZ for 2 hours and got sunburned from indirect sunlight. Just my 2c.
Yes, I too remember the hysteria, which in many ways foreshadowed today’s Climate Hysteria. We had programmes on the BBC called “The O-Zone” (a witty pun that kids would appreciate, concerned with environmental issues). I think there was even a porno movie called The O-Zone, but I’m guessing the O in that didn’t stand for oxygen.
The paper does not question Freons and CFCs as (co-)responsible elements in the stratospheric Ozone decomposition. The paper challenges the currently general “photochemical” theory of Freon and CFC breakdown (generating Bromine and Chlorine radicals respectively, the actual chemical species that catalyze O3 decomposition), claiming that the main activating energy is electrons from Cosmic Rays (CRs) instead of UV radiation. According to the study, the correlation of Antarctic O3 loss with the CR intensity became manifest only from 1992 up to now because the total amount of CFCs stayed nearly constant since the early 90s. Polar Stratospheric Cloud (PSC) ice particles seem to be important elements in this theory.
I think there is evidence (proxy) that there has always been ozone holes. It has to be proxy since there weren’t any “ozone holes until somebody named them.
But it has been known for eons that sunlight as the one of the msot prominent natural light sources; has alway had a varying color temperature; it varies seasonally every year, and it also varies eratically from time to time.
The change in apparent color temperature has been ascribed to variations in the UV and blue end of the solar spectrum due to changes in Ozone.
The one day; somebody said I think I’ll go and look for an ozone hole; and voilla! there it was. And the reaon it is where it is, is because during the Antarctic winter midnight; there is a well known shortage of solar irradiation of Antarctica. thisw is believed toi be due to the definition of night time as being an absence of sunlight.
And no sunlight; no XUV to break up O2 to form atomic Oxygen; which then (promptly) forms O3. Since Ozone is somewhat unstable anyway; if you have a decay of ozone, and a simultaneous lack of ozone formation; you get a hole. The principle applies to a lot of other things which disappear creating a shortage if they aren’t replaced.
George,
There is a problem with your analysis – while it is true that there is a diminishing of ozone above Antarctica during winter, there is a much greater loss during spring, peaking in the period from mid September to mid October. This loss is measured quantitatively and is accompanied by the appearance of the molecule ClO (Chlorine oxide). What is your theory to explain this?
“”””” jimmi says:
November 16, 2010 at 2:37 pm
George,
There is a problem with your analysis – while it is true that there is a diminishing of ozone above Antarctica during winter, there is a much greater loss during spring, peaking in the period from mid September to mid October. This loss is measured quantitatively and is accompanied by the appearance of the molecule ClO (Chlorine oxide). What is your theory to explain this? “””””
Well I didn’t say it was a complete closed theory of Ozone holes; just that it’s a fact. It is also a fact that if you look at the air mass zero, and air mass one solar spectrums, you will see that Ozone also absorbs solar energy in the range of 0.5 to 0.7 microns; green to deep red regions. It is known that ground level ozone is destroyed by sunlight.
So sunlight both creates ozone at very high altitudes where the XUV can penetrate; but also destroys it at lower altitudes; which maybe why ozone only persists to any extent in a very limited range in the atmosphere.
So what is your theory for the seasonal appearance of the ClO molecule. I’m under the impression that Chlorine destroys ozone in a catalytic process that releases the Chlorine to kill again. So then what is the function of ClO in the chemistry. I believe somebody who worked out a chemistry of chlorine destruction of ozone; got a Nobel Prize in chemistry for it; but If my memory serves; there was no observational evidence that such chemical reactions were actually taking place in the stratosphere.
The dissociation of O2 which is necessary to form ozone, I believe is a function of both XUV and also solar charged particle collisions in the upper atmosphere. The solar charged particles are influenced by the earth magnetic field; which also weakly affects the much higher energy Cosmic rays. The soalr particles typically get trapped by the earth magnetic field and spirtal around the field lines to reach the earth surface (if they can) in the regions around the magnetic poles. This process tends to reduce the density of solar charged particles above the polar regions; think of an iron dust map of a bar magnet field; there are quite low fields directly off the ends of the magnet compared to those between the poles.
But in any case; I believe there are peer reviewed papers that refute the Chlorine destruction of Ozone model; but I’m not up on the latest positions in that area; I have heard that it is a discredited model.
In any case; I’m not that worried about ozone depletion; some well credentialled people have suggested that ozone is simply the evidence that O2 is doing its job in absorbing solar UV. Well that is likely true of the XUV which doesn’t make it to the ground; but maybe UVA&B are another matter.
In any case; life on earth began in an atmosphere largely devoid of oxygen; so there must have been plenty of UVA&B, yet life flourished.