Antarctic sea ice increase not linked to ozone hole

From the AGU Weekly Journal Highlights

The Antarctic Ozone Hole - Image: NASA Goddard Space Flight Center

While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic. Some scientists have suggested that increased Antarctic sea ice extent can be explained by the ozone hole over Antarctica. Previous simulations have indicated that the ozone hole induces a large change in atmospheric circulation in austral summer and that this change in circulation could contribute to the changing Antarctic sea extent.

NSIDC Antarctic Sea Ice Extent

To learn more, Sigmond and Fyfe use a climate model, forced by monthly varying observed stratospheric ozone changes from 1979 to 2005, to simulate the effects of stratospheric ozone depletion on Antarctic sea ice extent.

Contrary to predictions of previous studies, their model finds that ozone depletion would lead to a year-round decrease in Antarctic sea ice extent rather than the increase that was observed. The results suggest that processes other than ozone depletion must be causing the observed increase in Antarctic sea ice extent. It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.

Title: Has the ozone hole contributed to increased Antarctic sea ice extent?

Authors: M. Sigmond: Department of Physics, University of Toronto, Toronto, Ontario, Canada;

J. C. Fyfe: Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, British Columbia, Canada.

Source: Geophysical Research Letters, doi:10.1029/2010GL044301, 2010 http://dx.doi.org/10.1029/2010GL044301

GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L18502, 5 PP., 2010
doi:10.1029/2010GL044301

Has the ozone hole contributed to increased Antarctic sea ice extent?

M. Sigmond

Department of Physics, University of Toronto, Toronto, Ontario, Canada

J. C. Fyfe

Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, British Columbia, Canada

Abstract:

Since the 1970s sea ice extent has decreased dramatically in the Northern Hemisphere and increased slightly in the Southern Hemisphere, a difference that is potentially explained by ozone depletion in the Southern Hemisphere stratosphere. In this study we consider the impact of stratospheric ozone depletion on Antarctic sea ice extent using a climate model forced with observed stratospheric ozone depletion from 1979 to 2005. Contrary to expectations, our model simulates a year-round decrease in Antarctic sea ice due to stratospheric ozone depletion. The largest percentage sea ice decrease in our model occurs in the austral summer near the coast of Antarctica, due to a mechanism involving offshore Ekman sea ice transport. The largest absolute decrease is simulated in the austral winter away from the coast of Antarctica, in response to an ocean warming that is consistent with a poleward shift of the large-scale pattern of sea surface temperature. Our model results strongly suggest that processes not linked to stratospheric ozone depletion must be invoked to explain the observed increase in Antarctic sea ice extent.

Received 11 June 2010; accepted 5 August 2010; published 29 September 2010.

Citation: Sigmond, M., and J. C. Fyfe (2010), Has the ozone hole contributed to increased Antarctic sea ice extent?, Geophys. Res. Lett., 37, L18502, doi:10.1029/2010GL044301.

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Related reading:

Galactic Cosmic Rays May Be Responsible For The Antarctic Ozone Hole

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63 Responses to Antarctic sea ice increase not linked to ozone hole

  1. Gil Dewart says:

    We see this happening a lot these days. Someone comes up with a plausible hypothesis, it is seized upon as the Ultimate Truth by those who want to believe it, and then it is ignominiously discarded.

  2. Neil says:

    So once again climate models have made a falsifiable prediction and come up wrong?

  3. Richard Sharpe says:

    Perhaps the models are wrong.

  4. Enneagram says:

    their model finds that ozone depletion would lead to a year-round decrease in Antarctic sea ice extent rather than the increase that was observed. The results suggest that processes other than ozone depletion must be causing the observed increase in Antarctic sea ice extent.
    http://wattsupwiththat.com/2010/10/05/oh-no-too-much-fresh-water-but-we-cant-tell/#comment-500131

  5. John Kehr says:

    One of the main culprits for the Arctic decrease is the Atlantic Multidecadal Oscillation (AMO). It is frustrating to see articles that do not take the ocean oscillations into account. These are well documented and known events, even if the cause is not understood.

    The winter (JJA) temperatures have been dropping in Antarctica and that would cause the increasing extent. Determining if the ozone hole which exists only when during those months is interesting, but difficult to prove. I can think of several arguments for and against that. That this study finds that they are unrelated isn’t really surprising. Since Antarctica has been cooling for a long time might also be playing a role.

    I truly believe that most of the difficulty in understanding climate is the short term perspective that most people have. Learning to grasp that long term changes are natural is difficult for people to accept. Especially when they keep getting told it is their fault. Our scientific tools are able to measure these small, gradual changes and they have to believe it is our fault.

    John Kehr

    The Inconvenient Skeptic

  6. John Kehr says:

    My mistake… June/July/August has been stable. It is the DJF period that has been trending down… Less warming in the summer would also translate to more extent. Oops.

  7. amabo says:

    “While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic.”

    I thought the increase in the Antarctic were pretty much equal to the decline in the Arctic. Am I wrong on this?

  8. Enneagram says:

    It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.
    LOL!; Could it be that the earth’s tilt does it?. When there is summer in the southern hemisphere the earth is the closer to the sun, that increases UV radiation, which in turn increases the ozone hole. During winter time protons (hydrogen nucleii) from solar flares and from cosmic rays react with ozone producing neutral molecules some (non modelers, of course) call “water”, which, when cold below freezing point, it is called “ice.”

  9. Vince Causey says:

    I read somewhere that while the arctic sea ice was declining, this was balanced by an increase in the antarctic. If this is the case ie, -x = +x at the other hemisphere, then how can it be accurate to describe arctic sea ice decline as dramatic while the antarctic increase is only slight?

    Anyone?

  10. Myron Mesecke says:

    “It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.”

    Land at the south pole with lots of ocean around it versus having ocean at the north pole with lots of land around it? I know this is too simple for science but surely this has some effect.

  11. vukcevic says:

    Two hemispheres are part of the same globe, but one of the Earth’s fundamental forces Geo- magnetic field, during last 400 years has exhibited totally different behaviour in each of the hemispheres,
    as you can see HERE .
    Science has not resolved all the known unknowns, and it is a bit short-sighted to exclude this variable from the Earth’s climatic events, until both climate and geomagnetic field are better understood.

  12. davidmhoffer says:

    So… some models based on some assumptions turn out to be contradicted by another model with different assumptions. Models falsifying models. Clearly what we need are still more models and then we can average all of the models, smooth them, graph the combined error bars, and reality should exist somewhere between them.

  13. Enneagram says:

    vukcevic says:
    October 5, 2010 at 2:13 pm
    Though it is very interesting that red and blue lines of your graph occupy opposite positions in opposite poles.

  14. Gary Pearse says:

    Does this mean that the antarctic ice is for some other reason expanding despite the strong warming affect of the ozone hole found by the researchers or that the model does not reflect the real world. I don’t know how their model works but a simple test would be to see if there is any assymetry between rates of ice extent increase and decrease wit h season changes (and opening and closing of the ozone hole). That is, if you have an additional heat source in the winter months, there should be an otherwise unexpected slowing of extent growth. I believe the general sinusoidal shape of the cycle essentiallly points to the effect of the ozone hole’s insignificance.

  15. PlainJane says:

    Vince
    I believe that there is a lot more ice in the antarctic than the arctic. Therefore as a proportion or percentage of arctic ice “x” is larger in the arctic than “x” in the antarctic.

    This means that their statements “sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic” may be true even if x arctic ice loss = x antarctic ice gain.

    It is the trend in ice – not the absolute amount of ice – that I believe they meant.

  16. David, UK says:

    Richard Sharpe says:
    October 5, 2010 at 12:58 pm

    Perhaps the models are wrong.

    I’m sure a little fudging tweaking here and there will rectify that. ‘S always worked before.

  17. Rob R says:

    One difference between the areas inside the Arctic and Antarctic Circles is that one is occupied largely by ocean and the other by land. In the down-under case the surface is on average about 1 to 2 miles above sea level whereas in the up-top case the surface is at sea level.

    So the two polar areas have lots of differences. Down-under the thick part of the atmosphere (the lower 2 miles) is basically missing. Does this impact on the presence/absence of the ozone hole? Is the ozone hole a largely natural feature of the Antarctic atmosphere? As far as I am aware the ozone hole was present during the very first year when definative measurements were made. Has such a hole always been present? Can we even determine this one way or other?

    Perhaps someone can enlighten me?

  18. A 2009 article “Increasing Antarctic Sea Ice Extent Linked to Ozone Hole” states: “Antarctic sea ice has increased by a small amount as a result of the ozone hole delaying the impact of greenhouse gas increases on the climate of the continent.” There are logical problems with the statement:
    1. the ozone hole has its annual maximum size in September – and this corresponds to the annual minimum in Antarctic sea ice; and
    2. the multi-annual trend is that the ozone hole has stabilized, whereas Antarctic sea ice continues to increase.

    See: http://www.appinsys.com/GlobalWarming/Ozone.htm

  19. Rob R says:

    Soho is looking rather blank today. Where have all the sunspots gone?

  20. Robert says:

    “It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.”

    Really? have they even seen Joe Bastardi’s theory. Shift the warmer temperatures northward with the PDO being warm, Artic melts, Antartic grows. when the PDO turns cold, Artic should grow, Antartic should shrink. How hard of a concept is that to understand?

  21. Tommy says:

    So take a climate model, change the ozone parameter based on observation, and notice the resulting ice extent is opposite of what is observed.

    If one assumes (by faith?) that the model is absolutely infallable, then yes, only “processes other than ozone depletion must be causing the observed increase in Antarctic sea ice extent”.

    But what if the pursuit of climate science did not require such faith? What if one was allowed to use contradictory observations as evidence that a hallowed model might be, dare I utter these words, less than perfect?

  22. Bob Tisdale says:

    Robert says: “Really? have they even seen Joe Bastardi’s theory. Shift the warmer temperatures northward with the PDO being warm, Artic melts, Antartic grows. when the PDO turns cold, Artic should grow, Antartic should shrink. How hard of a concept is that to understand?”

    The first problem: the PDO and the SST anomalies of the North Pacific, north of 20N, are inversely related. That is, over decadal periods, when the PDO is postive, the detrended SST anomalies of the North Pacific are negative, and vice versa.
    http://i51.tinypic.com/s2b6uq.jpg

    The second problem is the only direct connection between the North Pacific and the Arctic Ocean is the Bering Strait. You’d be better off relating the AMO to the Arctic Sea ice loss.

  23. ClimateWatcher says:

    But is Antarctic Sea Ice increase related to COOLING from CO2 over Antarctica?

    http://members.casema.nl/errenwijlens/co2/spectra.gif

  24. davidmhoffer says:

    Rob R;
    Re Ozone holes being natural

    They are. Pollution may cause them to be larger or smaller than normal, but they would exist regardless. Ozone is constantly being destroyed as certain frequencies of UV from the Sun strike it, and constantly being created as different frequencies of UV make it through the Ozone layer and strike Oxygen, ionizing it into Ozone. As the Ozone layer decreases in thickness, the amount of UV getting through increases and production goes up. When the Ozone layer is thicker than normal, less UV gets through and the production rate goes down. So the Ozone layer always fluctuates around an equilibrium point which can be influenced by other factors such a change in the mix of UV frequencies emitted by the Sun.

    But… since sunlight travels in a straight line it impacts the atmosphere “dead on” in the equatorial regions, but at an increasingly sharp angle as one moves toward the poles. As a consequence, the amount of Ozone creating UV has to go through a lot more atmosphere to get to the O2 layer, and the sharp angle means it is distributed across a larger area, so production is naturally much weaker at the poles, and hence a hole (or more accurately a depression) forms.

    In brief, because Ozone is produced by the Sun’s rays which are weakest at the poles, there is a depression there for the same reason is is cold there. The hole over the Antarctic is larger than the one over the Arctic because the earth’s orbit is elliptical and summer time recovery period favours the NH vs the SH.

  25. Stephen Wilde says:

    I’ll try to relate this to my New Climate Model.

    According to my hypothesis an active sun cools the stratosphere and reduces ozone (contrary to established climatology but in accordance with observations if anthropogenic CO2 and CFCs are ignored).

    As a result of the cooler stratosphere the strength of the temperature inversion at the tropopause weakens and the polar high pressure cells shrink (popsitive polar oscillations) with the other components of the air circulation including the various jet streams moving poleward. It is clear that just such a poleward shift occurred when the sun was more active and has now reversed (negative polar oscillations) with the less active sun, the reasons currently being unknown.

    More energy enters the tropical oceans during a period of warming with poleward jets because the subtropical high pressure systems expand as the clouds move poleward and there is reduced global albedo due to the cloud bands moving poleward so that the angle of incidence of solar energy onto the clouds declines with less cloud over the oceans.

    Wamer water from the tropics spreads poleward over time to both the Arctic and Antarctic.

    The Arctic being oceanic allows an ingress of that warmer water under the ice so more ice melts despite the fact that a tighter run of jet streams around the Arctic during a warming period with poleward jets should theoretically cool the Arctic by isolating it from southerly air flows. So when the troposphere is warming Arctic ice reduces but when the troposphere is cooling Arctic ice recovers.

    Note that poleward jets means a tighter run of winds around the poles with less air flowing in and out whilst equatorward jets means a less tight such run around the poles with more air flowing in and out.

    The Antarctic being continental only allows the warmer water to circulate around it which leads to more precipitation in the form of snow with an overall increase in sea ice extent and due to the intensity of the cold within Antarctica the warmer water never makes significant ingress except on the West Antarctic Peninsula which decreases in size even though the area of the Antarctic cold enough to create sea ice expands.

    The West Antarctic Peninsula would normally grow when the sun is weak with more frequent air flows into and out of the continental interior (a cooling period) but shrink when the jets are more poleward and more tightly directed around the continent (a warming period). The position of the West Antarctic Peninsula is a by product of the land distribution around it. The air flow around Antarctica is disturbed by the land mass of South America so when during a cooling period with equatorward jets
    there are more frequent flows of air into and out of the interior the favoured route for cold outflows is across the West Antarctic Peninsula which then grows.

    So during a tropospheric warming period the main part of Antarctica cools and expands because there is less in the way of northerlies entering the interior but the West Antarctic Peninsula is skimmed away by the tighter run of winds around the Antarctic from the more poleward jets.

    During a tropospheric cooling period the interior of Antarctic will be a little less cold due to more air flowing in and out from more equatorward jets but the West Antarctic Peninsula will grow back again because that is the favoured route for outflow of cold air.

    Thus:

    i) During a warming period Arctic ice and the West Antarctic Peninsula will decline whilst ice around Antarctica will increase.

    ii) During a cooling period Arctic ice and the West Antarctic Peninsula will grow whilst ice around Antarctica will decline.

    It’s just a matter of simple fluid dynamics, both the oceans and the air above displaying fluid characteristics.

  26. rbateman says:

    The Arctic Sea Ice Anomaly is down 1M km2, while the Antarctic Sea Ice Anomaly is up .65M km2.
    Not only are we talking about a silly .35M km2 anomaly globally, but each hemisphere is a moving target and NOT in synch with the other.
    The statement “While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic.” is both misleading and wrong.
    It would be correct to say the N. Hemisphere Sea Ice has declined marginally more than the the S. Hemisphere Sea Ice has increased.
    See here: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.area.arctic.png
    A starting annual average for the Arctic being 10M km2 dropping to 9M km2 is a loss of 10%.
    http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.area.antarctic.png
    A starting annual average for the Antarctic being 8.5M km2 has increased to 9M km2 (latest value)
    We’re playing with single digit percentage changes here.
    Death Spiral? I don’t think so.
    A big deal (in some circles) is being made out of a cherry-picked hemisphere while, at the same time, ignorance is bliss as far as the rest of the story goes.
    Hmpfff!

  27. Stephen Wilde says:

    An addendum to my previous comment.

    It can happen that an extreme warming phase with both oceans and sun combining to warm the troposphere could result in both Arctic and Antarctic shrinking together. Likewise an extreme cooling phase could see them expanding together.

    In that context note that currently there is an Arctic ice recovery in progress but as yet the Antarctic is not showing a persistent fall back from the recent ice quantity highs. Interesting times.

  28. Richard deSousa says:

    We continue to see models simulating all sorts of events in our climate but does anyone know how reliable these are these models? Can this model be just as flawed as the climate GCMs?

  29. John M says:

    This discussion reminds me of when I was browsing through a general science textbook written for high school students at a used book sale. As I recall, the book was written in 1970s and had a curious reference to the arctic and antarctic heating and cooling being out of phase (warm arctic, cool antarctic and vice versa). Not needing another elementary science textbook on my bookshelf, I passed (even for a buck :)), but it’s always been in the back of my mind. So on seeing this post, I googled, and found this more extensive treatment.

    http://books.google.com/books?id=EAcAAAAAMBAJ&pg=PA40&dq=arctic+antarctic+ice+coupled+historically&hl=en&ei=ramrTIyVIML98Aaw6pmsCA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCcQ6AEwADgU#v=onepage&q=arctic%20antarctic%20ice%20coupled%20historically&f=false

    Interesting historical perspective. The author even ends up in a “modern day” AGW frame of mind!

    But I digress. What I found most interesting was his numerous references to opposite behaviors of the two poles.

    “Warming of the arctic coincides with a period of increasing vigor of global atmospheric circulation while the cooling of recent decades [note: published in 1970] has been accompanied by weakening global circulation.”

    “These trends demonstrate the unity of the global system and also show the expected opposite phase between the antarctic ice region and the northern hemisphere. Global atmospheric circulation was greatest when iciness [of the antarctic region] was greatest and vice versa. Northern Hemisphere temperature trends follow global circulation intensity.” (Emphasis mine)

    Although it takes a while to sink in, Fig. 2 makes his case. Note the correlation coefficients in the inset are greatest for about a 5-6 year lag between antarctic ice in one location and northern hemisphere temperatures.

    I wonder how this reasoning has stood the test of time.

    btw, I also found it quaint how often he referred to the complexities and uncertainties in understanding climate. I guess they don’t make ‘em like they used to.

  30. feet2thefire says:

    @ Gil Dewart October 5, 2010 at 12:58 pm:

    We see this happening a lot these days. Someone comes up with a plausible hypothesis, it is seized upon as the Ultimate Truth by those who want to believe it, and then it is ignominiously discarded.

    Gil, IMHO you are being too kind when you use the term “plausible hypothesis.”

    Let’s call a spade a spade: It is another speculation.

  31. feet2thefire says:

    I have doubts about the hole in the ozone theory – the one that claims chlorinated fluorocarbons caused it. I always have.

    If any of the following is not factual, it would be nice of someone here corrected me:

    The vast majority of CFCs are/were created and released in the NH.

    1.) The Intertropical Convergence Zone (ITCZ) is a barrier between the NH atmospheric circulation and that of the SH. For example:

    By Matt Rosenberg, Geography Guide for About.com:

    Pollution Remains in Northern Hemisphere
    Friday October 3, 2008
    Discovery News reports that the ITCZ or Intertropical Convergence Zone acts as a barrier that keeps Northern Hemisphere pollution in that hemisphere, thus serving to keep the air of the less industrialized Southern Hemisphere relatively cleaner.

    This is in agreement with what I knew back in the 1980s.

    2.) In NH cities, excess ozone is a problem, enough that we have ozone alerts that occur from time to time. I don’t think I need to source this…

    Thus, for a CFC molecule to travel from a NH city to the Antarctic, it has to leave behind all the ozone in the vicinity of its creation. That seems odd, since according to the Ozone Hole hypothesis it should be mating up with thousands upon thousands of the ozone molecules there.

    Then it has to migrate out of the city and out of the Mid-Latitude Cell, then into the NH Hadley Cell, then cross the ITCZ barrier, then across the SH Hadley Cell, then cross the SH Mid-Latitude Cell, and only then will it be within the Polar Cell where lies the ozone hole.

    I have always had a tough time swallowing this hypothesis. I honestly believe they go it wrong. I know they have their chemistry “first principles” thing – that in theory that is what CFCs could do. I just can’t see why the CFCs would travel all the way to Antarctica when the NH polar region is so much closer. Why is there not a HUGE ozone hole a the North Pole?

    Right from the beginning, I have thought that the Ozone Hole was there all along but that they didn’t go looking for it until F. Sherwood Rowland considered it a possibility and they went to take a look.

    Due to the magnetic poles being there, the poles do not have the same environment as the rest of the atmosphere. I do not think we as yet know all the ways this can show up. IMHO one of those ways is as an ozone hole at that magnetic pole.

    In denying the CFC-ozone hole link, I may paint myself as a bigger quack than the rest of you folks here. But I think there is as little to recommend that idea as the AGW one. The science was “settled” it seems the moment they traveled to the Antarctic to check out Rowland’s concept. When they found it, they jumped to the conclusion that he was right. How else could it have been there, unless it was doing what he thought?

    I think it was just a lucky guess, and that he was right for the wrong reasons.

  32. Roger Knights says:

    Lots more soot is deposited in the arctic than the antarctic, especially in the last decade.

  33. Phil. says:

    feet2thefire says:
    October 5, 2010 at 5:49 pm
    I have doubts about the hole in the ozone theory – the one that claims chlorinated fluorocarbons caused it. I always have.

    If any of the following is not factual, it would be nice of someone here corrected me:

    The vast majority of CFCs are/were created and released in the NH.

    1.) The Intertropical Convergence Zone (ITCZ) is a barrier between the NH atmospheric circulation and that of the SH.

    It slows the mixing down, it doesn’t stop the mixing, as I recall it delays by about 5 years.

    2.) In NH cities, excess ozone is a problem, enough that we have ozone alerts that occur from time to time. I don’t think I need to source this…

    Thus, for a CFC molecule to travel from a NH city to the Antarctic, it has to leave behind all the ozone in the vicinity of its creation. That seems odd, since according to the Ozone Hole hypothesis it should be mating up with thousands upon thousands of the ozone molecules there.

    No, CFC molecules in the troposphere are inert and don’t react with ozone.

    Then it has to migrate out of the city and out of the Mid-Latitude Cell, then into the NH Hadley Cell, then cross the ITCZ barrier, then across the SH Hadley Cell, then cross the SH Mid-Latitude Cell, and only then will it be within the Polar Cell where lies the ozone hole.

    And there’s been plenty of time for that to happen.

    I have always had a tough time swallowing this hypothesis. I honestly believe they go it wrong. I know they have their chemistry “first principles” thing – that in theory that is what CFCs could do. I just can’t see why the CFCs would travel all the way to Antarctica when the NH polar region is so much closer. Why is there not a HUGE ozone hole a the North Pole?

    It travels to both, once in the stratosphere the CFC is slowly photodissociated by UV the reaction products can then react with ozone, this reaction is catalysed in the presence of polar stratospheric clouds (PSC) which are more common in the colder antarctic stratosphere. Hence the antarctic ozone hole, if the arctic stratosphere gets colder a hole will develop there too with an increase in PSCs, partial depletion of ozone has been observed to correlate with temperature over the arctic.

  34. Djozar says:

    I’ve had it with the ozone problem or issue. I’ve spent the last 20 years in the process of changing out CFC based refrigerants, and NOW I’m that a smaller ozone hole will create warming? And now we’re eliminating CFC’s to prevent CAGW?

    I’ve had it; I can’t use my name because of my Green brainwashed clients, and I’m at the end of my tether. I’m almost ready for them to use the “no pressure” on me.

    Quote Charlie Brown – Aaaaargh!

  35. AJB says:

    Don’t forget ozone depletion caused by big solar flare events:

    http://earthobservatory.nasa.gov/Features/ProtonOzone
    http://www.physorg.com/news93781896.html
    http://www.newscientist.com/article/dn11456-solar-superflare-shredded-earths-ozone.html

    However …

    The protons ionised nitrogen and oxygen molecules in the atmosphere, which then formed nitrogen oxides. The nitrogen oxides in turn reacted with ozone – a molecule made up of three oxygen atoms, breaking it into oxygen molecules and atomic oxygen.

    This breakdown caused global atmospheric ozone levels to drop by 5%. In comparison, chlorofluorocarbons (CFCs) and other chemicals have depleted the levels by about 3% in recent years, says team member Adrian Melott, a physicist at the University of Kansas in Lawrence, US.

    However, unlike CFCs and other ozone-depleting chemicals, which can persist in the atmosphere for some time, the flare-induced ozone thinning probably lasted for just four years, the researchers report. That is because the nitrogen oxides that cause the depletion eventually rain down with water or ice. Indeed, it was this acid rain that was eventually recorded in the ice cores.

  36. F. Ross says:

    Models, models, models!
    …I’ve always thought the best models were those in Victoria’s Secret.

  37. vukcevic says:

    Bob Tisdale says:
    October 5, 2010 at 3:03 pm
    The second problem is the only direct connection between the North Pacific and the Arctic Ocean is the Bering Strait. You’d be better off relating the AMO to the Arctic Sea ice loss.

    And the link is not very strong, the inflow through Bering Strait is about 10% of the total, the rest is from the Atlantic. Rivers fresh waters contribution is again only fraction of the Bering Strait current.

  38. DaveF says:

    F. Ross Oct 5 9:02 pm:
    “…the best models were those in Victoria’s Secret.”
    Absolutely. And where “denier” is a measurement of the sheerness of stockings!

  39. Stephen Wilde says:

    “Don’t forget ozone depletion caused by big solar flare events:”

    If ozone depletion can be caused by solar flare events then does it not follow that ozone is more likely to decline when the sun is generally more active thus leading to a cooling stratosphere ?

    That is just what was observed during cycles 19 through to 23 and they were all historically very active cycles even if cycle 20 was a bit less active than the others.

    So why is it assumed that a more active sun results in a warmer stratosphere when it clearly did not do so at that time ?

    And now with a less active sun the stratosphere is no longer cooling and shows signs of warming.

    All this is the exact opposite of established climatology yet critical to the air circulation in the troposphere because that circulation is affected by the strength of the temperature inversion at the tropopause.

  40. Stephen Wilde says:

    “James A. Marusek, Nuclear Physicist & Engineer, U.S. Department of the Navy, retired, suggests that ozone depletion in recent years is also due to solar flares. In 2003 and 2005 recorded flares coincided with ozone loss. The science keeps showing less likelihood that human activity has the level or even measurable impact on the upper atmosphere. I would like to see journalist stop taking liberty in stuffing worthwhile reports with unfounded claims that further a ruse perpetrated on the public to trigger an emotional reaction.”

  41. Stephen Wilde says:

    “By observing the Bastille Day solar event, Jackman and his colleagues found that the short-term effects of hydrogen oxides destroyed up to 70 percent of the ozone in the middle mesosphere. “The mesosphere was really shaken,” Jackman says. At the same time, ozone loss caused by longer-term nitrogen oxides cut out close to nine percent of the ozone in the upper stratosphere. But, Jackman says, only a few percent of total ozone resides in the mesosphere and upper stratosphere.

    “If you look at the total atmospheric column, from your head on up to the top of the atmosphere, this solar proton event depleted less than one percent of the total ozone in the Northern Hemisphere,” Jackman said. While that doesn’t sound like a lot, scientifically speaking the numbers for the specific atmospheric regions are quite significant.

    “This is an instance where we have a huge natural variance,” Jackman says. “The ultimate goal of a lot of our work is to understand the human impacts on ozone. In order to do that, you have to first be able to separate the natural effects on ozone.”

    And I recently posted a link that showed cooling of the mesosphere as well as the stratosphere when the sun was more active.

    Yet at the same time as the stratosphere and mesosphere cooled the troposphere and thermosphere warmed. Clearly there is differential warming and cooling of the different layers in response to changes in solar activity.

    Leif always asserts that a change in solar activity warms or cools all the layers in tandem !!

    My New Climate Model accommodates just such events.

  42. Stephen Wilde says:

    Anyway back to the essence of this thread.

    If the more active sun depletes ozone leading to a larger hole over the Antarctic then the stratosphere will cool because of the reduced warming effect from solar energy hitting the reduced number of ozone molecules.

    The Antarctic Oscillation turns more positive when the stratosphere cools with a tighter run of jets around the Antarctic (less inflow of warmer air and less outflow of cold air) so that the Antarctic interior will become colder and the area around the Antarctic cold enough for sea ice formation will expand. However the West Antarctic Peninsular will be steadily skimmed away by the tighter run of winds around Antarctica.

    That would appear to fit all the observations and it is an entirely natural process not requiring any input from human CO2 or CFCs.

  43. HR says:

    Sorry for stating the obvious but if we didn’t have the ozone hole would the increase in the extent be even greater? Seesaws are in order.

  44. Tom_R says:

    >> Phil. says:
    October 5, 2010 at 8:01 pm

    It travels to both, once in the stratosphere the CFC is slowly photodissociated by UV the reaction products can then react with ozone, this reaction is catalysed in the presence of polar stratospheric clouds (PSC) which are more common in the colder antarctic stratosphere. Hence the antarctic ozone hole, if the arctic stratosphere gets colder a hole will develop there too with an increase in PSCs, partial depletion of ozone has been observed to correlate with temperature over the arctic. <<

    1. Has there ever been an actual detection of CFC-12 molecules in the antarctic stratosphere? Do you have a reference?

    2. As I understand it, the theory claims it's the chlorine released from the CFC-12 that catalyzes the breakdown of the ozone. Since the oceans cover 70% of the Earth's surface, why assume that chlorine released from CFC-12 is a significant source compared to chlorine released from NaCl? NaCl is a much lighter molecule. Most free NaCl molecules would recrystalize or dissolve in water droplets before reaching the stratosphere, but it only takes a very small percentage to survive as free molecules to overwhelm the amount of chlorine from CFC-12.

  45. Enneagram says:

    F. Ross says:
    October 5, 2010 at 9:02 pm

    Models, models, models!
    …I’ve always thought the best models were those in Victoria’s Secret.

    Quote of the Week!

  46. Stephen Wilde says:

    “Sorry for stating the obvious but if we didn’t have the ozone hole would the increase in the extent be even greater? Seesaws are in order.”

    If there were no ozone hole over the Antarctic then the stratosphere would be warmer because of the presence of more ozone molecules responding to solar input.

    With a warmer stratosphere the polar oscillation would be more negative with the polar high pressure cells moving northward and possibly low pressure developing over the south pole itself. That would encourage more flows of air into and out of the Antarctic interior which would become slightly lesss cold and the area around the Antarctic cold enough for sea ice formation could well contract except for the West Antarctic Peninsula due to the surrounding land masses apparently altering the air flow around Antarctica to favour outflows of cold air across that Peninsula.

    So, more sea ice around Antarctica from depleted ozone and less sea ice around Antarctica from increased ozone all other things being equal (but they rarely are).

  47. 1DandyTroll says:

    Two ways to create more ice in the ocean:

    It’s getting slightly colder . . .

    The salt balance is getting unbalanced like when there’s somewhat more fresh water dumped into the oceans this makes the water “somehow” turn to ice and more ice reflect sun light and chilling the wind as it goes by making it colder still freezing more water.

    But of course, the fancy stuff is more intriguing.

  48. AJB says:

    Stephen Wilde says October 6, 2010 at 4:50 am
    Anyway back to the essence of this thread …

    Also don’t forget the heightened incidence of noctilucent clouds, what is this telling us? It appears more water is being broken down into OH ions + free H2 molecules due to increased UV which then recombines higher up. If not, why the increase in water ice at the mesopause, how is it getting there and in what initial state?

    http://www.nasa.gov/mission_pages/aim/edge_of_space.html

    Polar mesospheric clouds occur in the region where the sun first interacts with Earth’s atmosphere, causing chemical and thermal changes. Solar radiation at this altitude can break apart water vapor molecules, thus reducing the amount of water ice available to form ice crystals in the clouds. The solar ultraviolet radiation at work in this process is known to vary with the 11-year solar cycle.

    Satellite observations have shown a pattern of increasing solar ultraviolet radiation followed by declining brightness and frequency of these clouds over two solar cycles. But the change in solar activity occurs nearly a year before changes are seen in the clouds, indicating that the relationship is not a simple matter of direct cause and effect. It is not known why the two are so far out of sync with each other.

    Some good stuff coming out of the AIM project but early days yet I guess.

    http://aim.hamptonu.edu/mission/status.html
    http://aim.hamptonu.edu/library/index.html

    Seems to me that this effect must, to a lesser degree perhaps except when rare mega flares occur, be ozone and flare related too although the SOFIE instrument is not designed to look at this aspect AFAIK. Another intriguing aspect of these clouds is the odd lattice structures they seem to take on.

  49. Phil. says:

    Tom_R says:
    October 6, 2010 at 7:00 am
    >> Phil. says:
    October 5, 2010 at 8:01 pm

    It travels to both, once in the stratosphere the CFC is slowly photodissociated by UV the reaction products can then react with ozone, this reaction is catalysed in the presence of polar stratospheric clouds (PSC) which are more common in the colder antarctic stratosphere. Hence the antarctic ozone hole, if the arctic stratosphere gets colder a hole will develop there too with an increase in PSCs, partial depletion of ozone has been observed to correlate with temperature over the arctic. <<

    1. Has there ever been an actual detection of CFC-12 molecules in the antarctic stratosphere? Do you have a reference?

    Yes CFC and their photolysis products have been measured, first by Lovelock in the 70s as I recall.

    2. As I understand it, the theory claims it’s the chlorine released from the CFC-12 that catalyzes the breakdown of the ozone. Since the oceans cover 70% of the Earth’s surface, why assume that chlorine released from CFC-12 is a significant source compared to chlorine released from NaCl? NaCl is a much lighter molecule. Most free NaCl molecules would recrystalize or dissolve in water droplets before reaching the stratosphere, but it only takes a very small percentage to survive as free molecules to overwhelm the amount of chlorine from CFC-12.

    The percentage that does make it is way to small too have a major effect, nobody is “assum(ing) that chlorine released from CFC-12 is a significant source compared to chlorine released from NaCl”, it’s been measured (many times), fluorine containing products are a key marker.

    A good source with references is here: http://www.faqs.org/faqs/ozone-depletion/stratcl/

  50. AJB says:

    AJB says October 6, 2010 at 9:35 am
    I think I must have this arse backwards! NLCs have decreased of late, presumably because increased UV is breaking down more water vapour into OH + H2. How does this affect the ozone breakdown and why the lag? Anyone out there with the latest thinking on this stuff who can straighten this out?

  51. Enneagram says:

    Stephen Wilde says:
    October 6, 2010 at 8:33 am
    You are absolutely right, but you are not “a la mode liberal”, then you are a “bad kid” :-)

  52. Tom_R says:

    >>Tom_R Do you have a reference?

    Phil. October 6, 2010 at 9:58 am : Yes CFC and their photolysis products have been measured, first by Lovelock in the 70s as I recall. <> Phil. October 6, 2010 at 9:58 am : The percentage that does make it is way to small too have a major effect, nobody is “assum(ing) that chlorine released from CFC-12 is a significant source compared to chlorine released from NaCl”, it’s been measured (many times), fluorine containing products are a key marker. <<

    For fluorine, the concentrations are less that half those for chlorine. That says to me that natural chlorine accounts for more than half the stratospheric ozone depletion effect, even assuming no natural souce for fluorine. If there is a natural source of the stratospheric fluorine, then CFC-12 is even less of a source.

    http://www.springerlink.com/content/l4741h238x50q677/

    Also, the discussions of oceanic chlorine only consider HCl, but there is a significant amount of sodium in the stratosphere.

    http://www.pnas.org/content/79/8/2737.full.pdf

    "The presence of significant amounts of sodium in the upper
    atmosphere has been known since 1938, with the identification
    of the yellow radiation of the twilight air glow as the 589.3-nm
    emission from excited Na(2P) atoms (1, 2)."

  53. Phil. says:

    AJB says:
    October 6, 2010 at 10:13 am
    AJB says October 6, 2010 at 9:35 am
    I think I must have this arse backwards! NLCs have decreased of late, presumably because increased UV is breaking down more water vapour into OH + H2. How does this affect the ozone breakdown and why the lag? Anyone out there with the latest thinking on this stuff who can straighten this out?

    Those mesospheric clouds are above the ozone formation region, it’s stratospheric clouds that affect the ozone layer. If the mesosphere H2O concentration goes up then you might see increased NLC even with increased UV. As I recall stratospheric H2O has been going up.

  54. Phil. says:

    Tom_R says:
    October 6, 2010 at 12:49 pm
    >>Tom_R Do you have a reference?

    Phil. October 6, 2010 at 9:58 am : Yes CFC and their photolysis products have been measured, first by Lovelock in the 70s as I recall. Phil. October 6, 2010 at 9:58 am : The percentage that does make it is way to small too have a major effect, nobody is “assum(ing) that chlorine released from CFC-12 is a significant source compared to chlorine released from NaCl”, it’s been measured (many times), fluorine containing products are a key marker. <<

    For fluorine, the concentrations are less that half those for chlorine. That says to me that natural chlorine accounts for more than half the stratospheric ozone depletion effect, even assuming no natural souce for fluorine. If there is a natural source of the stratospheric fluorine, then CFC-12 is even less of a source.

    You asked me for a source, I gave it you, perhaps you will now do the courtesy of reading it before posting your erroneous theories?

  55. AJB says:

    Phil. says October 6, 2010 at 1:06 pm
    As I recall stratospheric H2O has been going up.

    Thanks Phil, any links on this? The intriguing bit for me is how this varying amount of water gets up to the mesopause and forms ice – in what form and what state changes are involved? Is this just nucleation and liquid water freezing or in fact an OH + H2 reaction and direct deposition? We’re at the very top of the homoshpere here, the reported time lag and lattice structures are all a bit odd.

    While minor amounts of H20, NLCs seem to be an indicator of sorts that tell us change is underway but as yet not how or why. Wikipedia has a reasonable article about them but I’m not sure how sound or up to date some this is:

    http://en.wikipedia.org/wiki/Noctilucent_clouds.

    The whole topic seems to have gone off the radar of late for ordinary Joes like me outside the climate field. I guess we’ll hear more from the AIMS mission as time passes.

  56. Phil. says:

    AJB says:
    October 6, 2010 at 5:14 pm
    Phil. says October 6, 2010 at 1:06 pm
    As I recall stratospheric H2O has been going up.

    Thanks Phil, any links on this? The intriguing bit for me is how this varying amount of water gets up to the mesopause and forms ice – in what form and what state changes are involved? Is this just nucleation and liquid water freezing or in fact an OH + H2 reaction and direct deposition? We’re at the very top of the homoshpere here, the reported time lag and lattice structures are all a bit odd.

    While minor amounts of H20, NLCs seem to be an indicator of sorts that tell us change is underway but as yet not how or why. Wikipedia has a reasonable article about them but I’m not sure how sound or up to date some this is:

    I’ll see what I can find, I recall a paper discussing increased methane concentration in the stratosphere and above leading to increased water and also increased ‘leaking’ through the tropical tropopause (from storms?).
    That Wiki article looks very good, well referenced.

  57. eadler says:

    So the Ozone hole doesn’t appear to be the reason for the lack of retreat in Antarctic sea ice. I don’t see that as remarkable.

    According to this link from NASA, stratification of fresh water at the surface inhibiting heat transfer from the lower ocean is an important factor. They also point out that increased precipitation (snow) will result in thicker ice.

    http://www.nasa.gov/topics/earth/features/antarctic_melting.html

  58. AJB says:

    Phil. says October 7, 2010 at 5:34 am

    A paper that may shed some light on this aspect (Ref 4 in the Wiki Article):
    Murray, B.J., E.J. Jensen
    Homogeneous nucleation of amorphous solid water particles in the upper mesosphere
    Journal of Atmospheric and Solar-Terrestrial Physics, 72, 51-61 doi:10.1016/j.jastp.2009.10.007, 2010.

    Abstract:

    Condensed water particles are known to exist in the high latitude upper mesosphere during the summer months. However, the mechanism or mechanisms through which they nucleate remains uncertain. It is postulated here that particles of amorphous solid water (ASW, condensed water with a non-crystalline structure) may nucleate homogeneously in the summer mesosphere. Using classical nucleation theory and a one-dimensional model, it is shown that more than 105 cm−3 amorphous solid water particles can nucleate homogeneously under mesopause conditions. Furthermore, it is shown that homogeneous nucleation competes with heterogeneous nucleation on meteoric smoke particles when the cooling rate is >0.5 K/h. The homogeneous nucleation of amorphous solid water could provide an explanation for the high density of ice particles (many thousands per cm3) thought to be required for electron depletions in the upper mesosphere. A parameterisation for homogeneous nucleation is presented which can be used in other mesospheric cloud models.

    Unfortunately it’s behind a pay-wall so $$$ for me but I’m guessing not for you :-). Dr Murray’s group at Leeds Uni seem to be doing lots of other interesting stuff that may whet your appetite: http://www.chem.leeds.ac.uk/BJM/publications.htm. Such a shame most of it isn’t publically accessible!

  59. AJB says:

    What a strange place to hide this … (scroll to bottom of page):
    http://www.chem.leeds.ac.uk/BJM/Interests.htm

    See also these pages:
    http://www.chem.leeds.ac.uk/JMCP/ice.html
    http://www.chem.leeds.ac.uk/JMCP/meteor_meso.html

    Curiouser and curiouser … a lot going on up there and these guys seem to be nailing it bit by bit. Cracking stuff guys, but come out from behind those damned pay-walls please! Think about it – who’s ultimately funding you?

  60. Northern Exposure says:

    Ok let me see if I have this straight :

    Melting ice – blame CO2
    Growing ice – blame ozone

    Got it.

  61. Spector says:

    I seem to recall one environmentalist saying he first became aware of how sensitive the environment was to human contamination after learning that the simple use of spray-can CFC’s had caused a huge hole to open up in the protective ozone layer over the Antarctic.

    As that hole is still there and apparently as large as ever, decades after the general ban on CFC use, perhaps that hole was a natural feature of the atmosphere that had just been discovered.

  62. feet2thefire says:

    @Spector –

    I am with you on that. I said at the time – literally – that it quite easily could have been a naturally occurring event, most likely due to the electromagnetic peculiarities of the magnetic pole. And I DID predict that even after we stopped using CFCs the hole would still be there, as big and bad as ever.

    But I also knew that they would say, “See? We told you the CFCs would have a long-term effect!”

    The thing about it was that the hole in the ozone issue was the run-up to global warming, although none of us on the outside had any idea at the time. That one was so successful – and so FAST – that it encouraged them.

    The earlier scare – acid rain – fell off the map after the federal gov’t put up $35M to actually go out and find empirical evidence. They even let the greens go out and collect the samples themselves. And what did the study prove? Only one or two small ponds in upstate New York – out of all the tens and tens of thousands of ponds and lakes in the U.S. had gone acidic at all (and there was no reason to think that those two, and only those two, had been caused by emissions. The result? The acid rain scare died a sudden death.

    But the greens learned a lesson: Don’t make claims that can be falsified.

    Ergo, a hole in the ozone – over the South Pole. No one except “them” (scientists) can go get samples. (I know someone who DID demand – and get – a sample of acid rain in a lake in NE Illinois.)

    Ergo, CO2 emissions causing a long-term devastating warming of the climate. It is no accident that they put the danger over 100 years into the future, where no one could go to see that it did or did not happen. (And everyone in 1990 who was claiming global warming would be long since dead and unavailable for castigation.)

    So, they had two trials – one fell flat on its face and the other was a screaming PR and policy success. By the end of the 1980s they were ready to push the envelope.

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