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Ozone holes and cosmic rays

Filed under: — gavin @ 14 December 2008 - (Italian)

ozone hole sept 2007Browsing through the blogosphere recently, I came across an interesting little story about the scientific method, scientific progress, and un-scientific spin (h/t Hank Roberts). The subject concerns the polar ozone hole in Antarctica and a possible role for cosmic rays in its variability on solar cycle timescales. The proponents of this link are a small research group at the University of Sherbrooke in Canada, who find themselves up against the mainstream stratospheric chemistry community and whose ideas are twisted out of all recognition by the more foolish of the usual suspects.

The story hit the ‘tubes earlier this year when researcher Q.B. Lu predicted that this years Antarctic ozone hole would be the biggest ever due to the actions of increased galactic cosmic rays (GCR) (because we are at solar minimum and GCR are inversely correlated to solar activity). This years peak ozone hole has now come and gone, and the prediction can therefore be evaluated. Unfortunately for Dr. Lu, this year’s hole was merely about average for the decade – a result that wasn’t too supportive for his theory.

This story made me a little curious about this though. Firstly, I didn’t initially understand why cosmic rays should be playing a role in ozone depletion – most of the cosmic ray effects that are usually discussed revolve around cloud-aerosol connections, but there are not many clouds in the stratosphere where the ozone holes form, and the ones there are (Polar Stratospheric Clouds – PSCs) are much more sensitive to temperature and water vapour than they are likely to be to background aerosols. On further investigation, it turns out that this idea has been out there for a few years (and was reported on then) and has subsequently been discussed in the ozone literature.

So let’s start with the background theory. Standard (Nobel-prize winning) stratospheric chemistry has tied ozone depletion to the increasing chlorine (Cl) load in the stratosphere which catalytically destroys ozone and comes from the photolytic dissolution of human-sourced chloro-fluoro-carbons (CFCs) high in the stratosphere. In the polar night, the presence of PSCs allows for a specific class of heterogeneous Cl reactions to occur on the surface of the cloud particles which turn out to be very efficient at destroying ozone. Hence the presence of an ozone hole in the very cold Antarctic polar vortex. Since PSCs are very sensitive to temperature, cold winter vortex conditions often presage a large ozone depletion the following spring (note that polar ozone depletion only occurs in sunlight and so is a spring time phenomena in both hemispheres). This is pretty much undisputed at this point (well, at least by serious scientists). We here at RealClimate even used this relationship to predict (successfully) a particularly large Arctic ozone depletion event in 2005.

Dr. Lu’s theory though posits an additional mechanism to release the Cl from the CFCs – and that is through GCR effects. Specifically, Lu suggests that the action of the GCR on CFCs attached to PSCs causes more Cl to be released, thus potentially delivering more Cl exactly where it could enhance polar depletion most effectively. The evidence for this comes from correlations of ozone loss with GCR (over a couple of solar cycles) and some suggestive lab experiments. Note that this does not call into question the anthropogenic source of the Cl which is still from CFCs.

However, Lu and colleagues’ theory has been strongly challenged in the literature. For instance, here, here and here. The comments focus on two main aspects, the weakness of the correlations (see figure), and the ancillary evidence that there isn’t any obvious evidence for CFC destruction in the polar vortex itself. In fact, correlations of CFCs with air mass tracers from the upper stratosphere are very stable, indicating that the photolytic conversion of the CFCs is by far the dominant source of Cl. These rebuttals seem quite compelling, and there doesn’t seem to be much continued support for Dr. Lu’s GCR idea. However, Lu is still pushing it (hence the press release this year just weeks before the prediction would be put to the test). One might think Dr. Lu’s ideas wrong, but one can’t fault his bravery in putting them to the test.

As we stated above, the un-exceptional ozone loss this year pretty much undermines the correlations that were at the heart of Lu’s idea. Thus I predict that this is unlikely to be discussed very much more in the literature except as an example of how interesting ideas are generated, discussed, tested and (in this case) found wanting. This indeed is how scientific progress is made.

But, as has often been noted, the contrarian-sphere is a world on its own. It was inevitable that the headline link between GCR and ozone holes would entice the old-school ozone depletion skeptics and ‘everything-is-solar” proponents out of their burrows. Tim Ball led the charge. Now Dr. Ball is a long time skeptic on the human influence on ozone depletion as well as climate change, and so he couldn’t resist the occasion to opine on all theories anthropogenic:

Nurtured by environmental hysteria and the determination to show all changes in the natural world are due to human activity, the claim CFCs were destroying ozone jumped directly from an unproven hypothesis to a scientific fact.

He also includes standard statements implying that scientists implicated CFCs in ozone depletion to deprive the developing world of refrigeration (oh my!), how there hasn’t been a change in ozone depletion in any case (despite showing a series of figures obviously demonstrating this – see here as well) and so on…. He did however note that Dr. Lu’s theories don’t actually change any of the mainstream prescriptions for dealing with ozone depletion (though he does get confused about the CO2 impact on stratospheric temperatures – it makes them colder, not warmer). But the real prize goes to Dennis “unstoppable” Avery who suggests that Dr. Lu’s theories will confirm a link of GCR to climate change:

If the South Pole gets an ozone-hole maximum in the coming weeks, it will strengthen the case for cosmic rays, and endorse a Modern Warming driven by solar variations rather than human-emitted CO2.

This is the same logic as assuming that because salt makes food taste better, throwing it behind your shoulder must bring luck. That is, they are just not connected. And I’m pretty sure he won’t accept the logical corollary. Needless to say this is a very feeble grasping at straws. But to quote a recent Monbiot article:

There is no pool so shallow that a thousand bloggers won’t drown in it.

Nor an ozone hole it seems either.

121 Responses to “Ozone holes and cosmic rays”

  1. 101
    Hank Roberts says:

    21st Conference on Climate Variability and Change

    Additive effect of two solar forcing mechanisms and influences on tropical Pacific climate

    Gerald A. Meehl, NCAR, Boulder, CO; and J. M. Arblaster, F. Sassi, and K. Matthes

    Three climate model experiments are analyzed to study the relative contributions of two solar forcing mechanisms. One involves ozone in the stratosphere absorbing more UV radiation in peak solar years, ultimately resulting in enhanced vertical motion and greater precipitation in the tropical Pacific. A second mechanism involves coupled air-sea interaction at the surface in the tropical Pacific where greater solar forcing during peaks of the 11 year solar cycle produces increased evaporation in the relatively cloud-free Pacific subtropics, and additional moisture that is carried by the trade winds to strengthen precipitation in the ITCZ and SPCZ. Stronger trades in the intensified Hadley and Walker Cells produce greater upwelling, and a La Nina-like SST response in the eastern equatorial Pacific. A version of CCSM3 (coupled to a dynamical ocean but with no resolved stratosphere or ozone chemistry) captures the coupled air-sea mechanism and produces a weak La Nina-like response during peaks in solar forcing as seen in the observations. A version of WACCM (including a resolved stratosphere and ozone chemistry) run with climatological SSTs reproduces the stratospheric ozone mechanism with stronger precipitation in the western Pacific, ITCZ and SPCZ. Another version of WACCM coupled to the dynamical ocean of CCSM3 simulates both the stratospheric ozone and coupled air-sea mechanisms and shows a stronger response by about a factor of two compared to the CCSM3 with just the coupled air-sea mechanism. These results indicate that the two solar mechanisms act in the same sense and are additive to first order to produce a La Nina-like SST response in the tropical Pacific during peaks in solar forcing.

    Poster Session 3, Global dynamics and prediction – posters Tuesday, 13 January 2009, 9:45 AM-11:00 AM

  2. 102
    Hank Roberts says:

    PS, the links I posted above in this posting:
    5 January 2009 at 8:20 PM

    are broken (the color doesn’t extend the whole way through to the end of what’s obviously part of the link — so it’s not being recognized).

    If you copy the whole thing, and paste it into your browser, it will work correctly.

    I do highly recommend that book I quoted a bit from. It’s a very readable perspective on the story, at least reading as an amateur. I’d be most curious to know what the real scientists think of that if you have time to look at the book — does it get the story right?

    (Any time you see someone try to post link here that shows up in two colors and is “not found” — just copy the whole thing and paste it into your browser. The software interprets some characters as the end of a link when they belong in the middle of it. Maybe there’s a way to edit that in Preview, but I haven’t figured it out yet. I post the whole thing instead of hiding it behind a “click here” because I want people to know for sure what they’re going to get.)

  3. 103

    Interesting stuff, Hank; thanks for sharing your searches.

  4. 104

    In re Hank @100:

    The SSN for December ’08 was 0.8, which is lower than August ’08 and the number of spotless days since SC23 exceeds any transition since you and I were born.

    So … yeah, this has all the makings of a grand minimum. Care to name the last solar cycle that had this many spotless days during the transition?

  5. 105

    And now for Something Completely …… Real
    A bit of more interesting news than the same old from journalists not so well versed.
    For the hard core RC Stratosphere fans:

    ever heard of 9% RH way up in the stratosphere?

    Care to look near the center of the vortex?

  6. 106

    Wayne, would you care to add a few words of interpretation on the image from the second link for those of us who are not so hard-core? (I at least struggle a bit to infer units from values.)

  7. 107
    Ken says:

    POST 92: I’m agnostic on that question, myself, but I’m going to say that IMO your argument is basically of the “straw man” type–that is, you are persistently critiquing the original version of the CFC hypothesis, when pretty much everyone has moved on from this concept. (Note, for instance, that post heading this thread is entirely concerned with ozone destruction within the polar vortex.) You’re bashing away at a dead horse, and seem to be generalizing (invalidly) from the specifics of that argument to the wider ozone question. Most folks are just not going to be all that interested, I’m afraid.

    Yes, Kevin, most folks have moved on. It is a “scientific fact” now. But this is not a “straw man” argument. I am not misrepresenting the current dogma. It is a simple reevaluation of the evidence used to make the dogma a scientific fact…the original version. Everything I have presented was current research at the time that policy was being formulated. None of it has been shown to be “disinformation”. Yet, even today, outside of the Antarctic polar vortex (and some computer models) there is no evidence – data – that can put CFCs and long-term ozone depletion together in a coherent fashion. [edit]

    [Response: Enough. You keep repeating things that have been demonstrated clearly to not be true. I pointed you to the data numerous times. Hank pointed you to the CCSP report. You have the 2006 WMO Ozone assessment in front of you. This is just classic troll behaviour. Take it somewhere else. – gavin]

  8. 108

    #106 Kevin, Its the vortex with a rather large center where the winds are not so strong. Ya, the numbers are not so good, green dashed lines are temperatures at 10 mb , note -80 C off Banks Island, and the height lines at 10 mb, in blue, at 40 meter intervals, 29320 meters around the center
    shades of blue is maximum wind speeds, not as strong as last year yet. 150 knots was the fastest I read. Last year it was Tornado speeds. In the center of the archipelago, there is hardly a tropopause
    with extraordinary high levels of RH. Stratospheric scientists are interested in this phenomena….

  9. 109

    Thanks, Wayne, that is helpful.

  10. 110
    Ken says:

    Hank (POST 98) delights in telling us that one needs simply to go onto Google to find out what the “smoking gun” was at 30°N. This is what returns from his search:

    “The ‘smoking gun’refers not to the shape of the curves as plotted,nor to a quirk
    of the experimental apparatus or the aircraft! It is a reference to the mythology
    of the American West,where the sheriffcomes upon a recently dead body in the
    street. He looks up to see in the porch of a nearby building a man holding a
    handgun, with smoke still rising from the muzzle. In the present case the
    imprint of the same detailed pattern on the ClO curve as is seen in the ozone
    depletion, points clearly to ClO as the culprit.”

    Hank…the “porch” in question here is the Antarctic polar vortex, NOT the stratosphere at 30°N. There is no ‘smoking gun’ for the stratosphere outside of the polar vortex. You keep coming up with a blizzard of stuff from the polar ozone studies but nothing from outside this geographically limited area.

    Then, also from your philosophical reference…
    “Suppose that there had been no further development, experimental or
    theoretical, after the rival theories were first articulated, and that the
    ‘smoking gun’ result from the AAOE had been obtained in isolation.
    Could such a result have been decisive in choosing between three rival
    embryonic theories? I am contending that it could have done so,and that
    it could have done so quite definitely. The essence of the result is that
    wherever ozone is disappearing, ClO levels are anomalously high.”

    Note the last sentence: This ‘essence’ is seen at places in the polar vortex. But this essence is NOT what is seen at 30°N. Indeed, as I have tried to point out, it is the reverse at 30°N. Wherever ozone is disappearing (below 25 km; Stolarski et al., 1992), ClO levels are low to non-existent (Zander et al., 1992). The gas-phase “standard” model uses these catalytic couplet equations: Cl + O3 = ClO + O2 and then ClO + O = Cl + O2. Explain, please, how ClO ABOVE 25 km in the mid-latitudes can be destroying ozone BELOW 25 km.

  11. 111
    Hank Roberts says:

    Sure, and Darwin was wrong too, in the details. As is every early scientific work in any field. That’s how it works. Your point is what? do you claim there’s something wrong with what we’re doing now? That science does not proceed directly from perfect theory to political decision? That if we hadn’t looked at the Antarctic, we wouldn’t have acted to control CFCs and the result would be disastrous? Or something else?

    The point you miss is that long-lived, persistent new compounds added to the atmosphere build up slowly over a long period of time and if we hadn’t stopped adding them the problem would have been intractable by now. We were lucky to find a stronger effect earlier than the first ideas suggested — a slower weaker effect would have added up to as much of a problem over a longer period of time. Can you think of any current analogy?

    Society is damned lucky when a scientist’s work leads to early discovery of serious problems before they become enormous.

    Consider tobacco. Consider antibiotic resistance. Consider estrogen mimics. Consider much else you can find in the public health journals. All cases where the science was good early on but the societal response has been far slower while the commercial development moved very quickly because there was no egregious early problem to point out, only the slow accumulation of the problem.

    You seem to think you have a point, but you haven’t expressed it.
    Take everything you say. Add the “So what?” if it’s pertinent to this thread. Are you just trying to argue against the precautionary principle?

  12. 112
    Hank Roberts says:

    A bit more on this general area — recently:
    “… there is a secular increase in the occurrence frequency of polar mesospheric clouds (PMC), along with an anti-correlation with the solar activity. The combined data records from the Solar Backscatter Ultraviolet (SBUV and SBUV/2) instruments provide the longest satellite record (28 years) of the PMC frequency of occurrence.”

    From 1995:
    Global change in the mesosphere-lower thermosphere region: has it already arrived?
    G.E. Thomas

    “… At the cold mesopause at high latitude, …. All models predict a future lowering of temperature throughout much, if not all of the MLT region, as a result of enhanced IR cooling and dynamical feedbacks…”

  13. 113
    jae says:

    271, Seems to be debatable and very dependant upon what “costs” are included.

    But the dreamers of the world also have to consider that we still have to have a generation capacity capable of meeting full demand for those many times when the wind doesn’t blow (like when it’s really cold) and the sun doesn’t shine (like at night and the winter, for all practical purposes). The prevalence of too many dreamers and too few engineer/scientists in la-la-liberal-land is going to be our demise. Almost guaranteed!

  14. 114

    jae posts:

    But the dreamers of the world also have to consider that we still have to have a generation capacity capable of meeting full demand for those many times when the wind doesn’t blow (like when it’s really cold) and the sun doesn’t shine (like at night and the winter, for all practical purposes). The prevalence of too many dreamers and too few engineer/scientists in la-la-liberal-land is going to be our demise. Almost guaranteed!

    1. By storing excess heat in molten salts, many solar thermal plants achieve nearly 24/7 operation.

    2. Energy can also be stored in batteries, flywheels, capacitors, compressed air, and water pumped uphill.

    3. Geothermal energy runs 24/7.

    4. Biofuels can be burned at any hour of the day.

    5. Wide-area electric grids using direct current could even out the power even from highly intermittent point sources.

  15. 115
    Hank Roberts says:

    But we’re digressing.

    Has anyone gotten a response from the Sherbrooke people?

    I’ve tried again a while ago with their PR department but not heard any response; the second time the guy told me he’d pass the request for an update on to the management there.

  16. 116
    Erkan says:

    Thanks, Wayne, that is helpful. :)

  17. 117
    Hank Roberts says:


    “MUNICH, Germany — Researchers from Fraunhofer have managed to squeezed an efficiency of 41 percent out of photovoltaic cells. The Freiburg, Germany, based institute claims this is world record….” 01/15/2009

    Not ready for commercial production yet, it’s a concentrator, but it’s a new way to move the apparently inevitable defects in solar cells out of the working area, and to make them use more of the solar spectrum rather than using only a narrow band.

  18. 118
    Hank Roberts says:

    OK, Waterloo’s PR office is back at it. I never heard back from my third attempt to contact them last fall. Now they’ve moved the goalpost and called it a touchdown. NOTE, I have no idea if the actual science paper said what the university PR offic claims, either last time or this time, yet.

    Last year: “predicts … largest”
    2008-09-16 10:09:59
    New theory predicts the largest ozone hole over Antarctica will occur this

    WATERLOO, Ont. (Tuesday, Sept. 16, 2008) — A University of Waterloo
    scientist says that cosmic rays are a key cause for expanding the hole in
    the ozone layer over the South Pole — and predicts the largest ozone hole
    will occur in one or two weeks. …

    They’re still at it (“fifth largest” hole as “proof”)
    2009-03-23 10:05:59
    “UW prof says cyclic ozone hole proves cosmic ray theory

    WATERLOO, Ont. (Monday, March 23, 2009) — A University of Waterloo
    scientist says that an observed cyclic hole in the ozone layer provides
    proof of a new ozone depletion theory involving cosmic rays, a theory
    outlined in his new study, just published in Physical Review Letters….”

    I hope it’s just bad writing by the PR office at the university there.

    Do a little reading before you jump on this one, folks, it’s really hard to tell who actually is claiming what. (2001 story on the same researcher, gives detail on lab experiment done that’s worth reading, no idea what else happened between then and now tho’)

    CBC headline is actually informative, deserves some kind of award!
    “New theory blames cosmic rays for helping CFCs deplete ozone
    Fellow scientists say Waterloo professor’s hypothesis needs more study”

    Here’s the 2001 paper:

    Cited by has a fairly long list including criticism and responses:

    — this will take you up to the most recent reply by the authors to criticism. This abstract from that link makes me really wonder if this is mostly a university PR department overblowing work.

    In our recent paper [J. Chem. Phys.128, 041102 (2008)], we reported a femtosecond time-resolved laser spectroscopic study of the electron transfer reaction of CCl4 in liquid ethanol. Our results provide direct evidence of the resonant dissociative electron transfer (RDET) of the presolvated electron to CCl4, and indicate that RDET can be an efficient process in an aqueous environment. In a recent Comment, the author argues that the relevance of diethanolamine (DEA) induced destruction of chlorofluorocarbons (CFCs) in the polar stratosphere as a possible pathway for chemical ozone destruction should not be a motivation for further studies of DEA on CFC molecules, as no correlation is observed between polar chemical ozone loss and cosmic ray activity. Here, we show that this claim is misleading: it is made by using inconclusive and ambiguous data while ignoring pronounced and well-documented data. ”


    My recommendation — read papers before commenting.
    Or at least, SAY if you’ve bothered to read them before commenting on the science.

  19. 119
    Hank Roberts says:

    A reminder, most of the papers in this particular area are NOT available online to nonsubscribers.
    Someone who wants to actually comment on or do a review of this will have to do some serious library work.
    _____ReCaptcha Says____
    rough activities]

  20. 120
    Mark says:

    “capacity capable of meeting full demand for those many times when the wind doesn’t blow (like when it’s really cold) and the sun doesn’t shine (like at night and the winter, for all practical purposes).”

    And you can move electricity about using some sort of high-voltage wire system across the country. A grid across the nation for electrical power.

    You can have better insulation and the need for heating when it is cold is reduced.

    You can have more efficient lighting for when it’s dark. Or don’t work so late when it’s dark (isn’t that what all that the “daylight saving” about? Change the midday so the sun is used in the evening-biased work day 9-5?).

    Scotland uses about 20% of the US average. It’s quite a long way north. It’s quite cold and dark there and the winter nights lasts a long time. They are a first-world country with all the modern amenities that implies.

    If the US were worried about baseload, why don’t they cut the baseload down?

    If the UK is worried, why do they have so many sodium lights on at night when everyone is inside in the light? Or businesses lit up like it were daytime when closed?

  21. 121
    Hank Roberts says:

    Lu’s paper allows for more variability than the university PR department’s press release.

    The fall 2008 paper is on his website:
    ” Dr. Lu’s Latest Proof of the Cosmic Ray Theory for the Ozone Hole …”

    “… the monthly mean total O3 over Antarctica in October 2008 is predicted to be about 187 DU, close to the measured value of 181 DU in 2006 (one of the deepest holes) [28]. Because of the accumulative effect of CR-driven electron reaction products, there may exist a time delay of about 1 year between the CR intensity maximum and the maximum ozone loss in the polar hole. For instance, the largest ozone holes were observed in 1987 and 1998, respectively, corresponding to the CR intensity maxima observed in 1986 and 1997. Although atmospheric dynamics and meteorological conditions could influence the CR effect and lead to large fluctuations of the O3 hole from year to year, a long-term trend of the polar O3 loss (hole) is predictable. It is interesting to examine these predictions….”