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  1. Drew, I have two questions for you: Last month your paper suggested that ozone variability played a much stronger role in local forcing of temperature at certain times of year, compared to background radiative forcing; would a finding such as this, if it were confirmed, have any effect on the results of your work? Secondly, if we are seeing Polar amplification of global warming, will there come a point when temperatures do not get low enough to affect the chemistry in the lower atmosphere?

    [Response: Tis the other way round – GW cools the stratosphere, remember – so the worry is that temperatures might decrease enough for enhanced OD – William]

    Comment by Fergus Brown — 28 Sep 2007 @ 4:49 PM

  2. Is this lab result meant to simulate what happens in either of the two situations? ((1) upper stratosphere plus strong sunlight; (2) polar springtime lower stratosphere cold enough for ice crystals.)

    I remember the latter was a recent surprise, as the stratosphere got cold enough often enough, some winters, for it to develop.

    Or — is this lab work to understand the reaction in very pure conditions — eliminating anything else to make sure nothing could be present that, like those ice crystals, would affect the rate?

    Comment by Hank Roberts — 28 Sep 2007 @ 5:36 PM

  3. One looks forward to the quantification of how the emerging Cl2O2 rate data will effect model estimates of the trade off between reduced energy efficiency ,and hence increased CO2 RF from thermal station powered air conditioning, and demands for the accelerated phase out of HCFC’s in the name of limiting their climate forcing. Since AGW correlates to increased air conditioner use , the rate shift may give rise to an interesting policy conundrum.

    Comment by Russell Seitz — 28 Sep 2007 @ 7:09 PM

  4. Understanding an intermediate step doesn’t change the outcome.
    You can still fry an egg after realizing you don’t fully understand how and why protein denatures.

    > Indian chemical companies are happy to ship as much
    > chlorofluorocarbons as needed, Mr. Bothelo said. When
    > asked what the chemical looks like, he abruptly had a
    > mechanic pour a little out of a battered metal tank onto
    > the oil-stained ground. The milky gas flowed toward the
    > dirt, bounced and then faded away, vanishing into the air.
    > “If it were something so bad,” Mr. Bothelo said, “they
    > would not legally sell it.”

    Comment by Hank Roberts — 28 Sep 2007 @ 10:47 PM

  5. It seems to me that the Sander lab’s new result is difficult to reconcile with a lot of good ab initio theory on ClOOCl out there as well as results of molecular beam photolysis experiments.

    Minor quibble Cl2O2 is the empirical formula that fits three isomers. The one that is important is ClOOCl. There is some interesting matrix isolation work from the early 90s that managed to interconvert all the isomers.

    Comment by Eli Rabett — 28 Sep 2007 @ 11:18 PM

  6. A thought that just hit, is that it is a lot easier to photodissociate the other two isomers, and the interconversion might happen on the PSC particles (this is a real WAGNER – wild assed guess, no explanation required)

    Comment by Eli Rabett — 28 Sep 2007 @ 11:21 PM

  7. Eli:
    Point well taken- molecular beam and mass spec vacuum systems are designed to eliminate pump aerosols, and keep surface interactions out of play and the line of flight.

    Comment by Russell Seitz — 29 Sep 2007 @ 6:25 AM

  8. If the chemistry of ozone deletion is so well understood, why have the predictions of healing of the ozone “hole” not come to pass?

    [Response: The predictions of recovery have all suggested that it will take decades for the Cl/Br burden to decrease, and there is the added complication of increasing CO2 making the stratosphere colder and favoring ozone destruction (see Shindell et al 1999 for instance). However, we should be near the minimum now. – gavin]

    Comment by joel — 29 Sep 2007 @ 10:39 PM

  9. A bit OT, but: is the recent agreement to speed up timelines on eliminating HCFCs a “win” for
    cutting back on greenhouse gas emissions, as advertised, or is it sidestepping the issue, as some have

    Comment by bigcitylib — 30 Sep 2007 @ 6:32 AM

  10. The elementary questions are collected here with links to answers
    at the top of page and in comments here:
    Current condition reports here:

    Comment by Hank Roberts — 30 Sep 2007 @ 10:28 AM

  11. Hank: Thanks for the links. Now here’s an even more elementary question: How does GW lead to stratopspheric cooling? I live w/ an unrepentent denier.

    Comment by James Cottingham — 30 Sep 2007 @ 11:54 AM

  12. James, putting your question into Google leads to this:
    RealClimate » Why does the stratosphere cool when the troposphere …

    [Response: Actually, that was probably the worst post I ever wrote, and it’s not correct. I should delete it, but it stays around for historical reasons I guess. A better explanation is available through this link: . The basic explanation involves the fact that you have multiple lines where IR is absorbed in the troposphere. If you increase CO2, you get a suppression of upward LW into the stratosphere in the CO2 bands at the same time you get increased outward radiation from the stratosphere, producing a cooling. The total upward LW is roughly the same because the other bands (from water vapour mainly) make up for the deficit at the CO2 bands. – gavin]

    Comment by Hank Roberts — 30 Sep 2007 @ 12:20 PM

  13. Thank you Gavin. (Blush. No ‘wisdom’ option on search.) You could edit the beginning of that ‘worst post’ so Google will go to the edit.

    Comment by Hank Roberts — 30 Sep 2007 @ 12:52 PM

  14. Gavin (inline to #12) wrote:

    A better explanation is available through this link:

    First me and now Hank.


    People are going to continue to refer to the post – particularly since it is dealing with a topic that is at first counterintuitive for the layman. Likewise people are going to refer to it at other websites.

    Personally I am glad you keep it around. But what I would recommend is a disclaimer at the top to the effect that it contains mistakes, its being kept around for historical reasons, that you think the discussion itself is valuable (as I would assume you do), and then a link to the post “The Sky is Falling” as what you would recommend in its place.

    This will make things easier for you (since you wouldn’t even have to do the inline when people refer to it in discussions – in essence “the inline” would already be there at the top of the old post) and at the same time help those who are coming in from other websites – who otherwise won’t know that there are problems with the piece itself until they get to the discussion.

    Comment by Timothy Chase — 30 Sep 2007 @ 1:12 PM

  15. PS to #14


    I see that you already did what I suggested.

    Comment by Timothy Chase — 30 Sep 2007 @ 1:16 PM

  16. Does RC concur, and approve of the EPA’s recent decision to allow use of methyl iodide as a soil fumigant (with subsequent release of MeI to the atmosphere) as protective of atmospheric chemistry?

    Comment by Aaron Lewis — 30 Sep 2007 @ 1:52 PM

  17. Removing sources of atmospheric bromine is good.

    Replacing methyl bromide, long known as an immediate hazard to public health, with “methyl iodide, marketed by Tokyo-based Arysta LifeScience Corp” — also a known hazard to public health — isn’t.

    “… Cornell’s nobel laureate (1981, chemistry) Roald Hoffman made his own assessment: “I wouldn’t like to live near a field where it’s applied.” I guess I can infer that also means he wouldn’t like to work in the field.”

    Comment by Hank Roberts — 30 Sep 2007 @ 2:46 PM

  18. James Cottingham (#11) wrote:

    Hank: Thanks for the links. Now here’s an even more elementary question: How does GW lead to stratopspheric cooling? I live w/ an unrepentent denier.

    A quick note….

    Statospheric cooling is indicative of an increased greenhouse effect. One of the fingerprints, if you will. If global warming were the result of increased solar radiation, then one would expect both the troposphere and the stratosphere to become warmer, but the stratosphere has cooled – just as one would expect given an increased greenhouse effect due to the reduction in the amount CO2-band longwave radiation – and as has been predicted.

    Comment by Timothy Chase — 30 Sep 2007 @ 3:19 PM

  19. Re 17
    Thanks Hank for your every vigilant help.

    I know that MeI is more toxic than MeBr, and I particularly hate the thought of exposing of innocent populations to vapor drift as agricultural towns like Salinas, Stockton, and Fresno develop other industries. (Some days I am less concerned about the health of non-agricultural workers in Sacramento.)

    However, I see stuff like

    Photochemical aspects of tropospheric iodine behavior by Jenkin, et al, in Journal of Atmospheric Chemistry, 1985

    and I wonder if the current lack of concern by the EPA for effects of Iodine on O3 is because of a lack of effect, or because we just have not (yet) released enough Iodine into the troposphere to see an effect.

    That is; Is it no effect, or just no data?

    Comment by Aaron Lewis — 30 Sep 2007 @ 6:39 PM

  20. Does Realclimate have any connection with any other environmental groups such as greenpeace?

    [Response: No, but see our earlier statements. -gavin]

    Comment by paul — 30 Sep 2007 @ 8:39 PM

  21. Although referenced in the article Gavin points to, one can simply go to Dr. Elmar Uherek’s explanation, which wins the gold leaf award on stratospheric cooling

    Comment by Eli Rabett — 30 Sep 2007 @ 8:45 PM

  22. One perhaps nitpicky point… The article says “chlorine, the more important of the two [relative to Br]”– but I’m pretty sure that, atom for atom, Br is stronger. Cl is just “more important” because there’s more of it.

    Comment by Sean D — 1 Oct 2007 @ 11:47 AM

  23. Does Realclimate have any connection with any other environmental groups such as greenpeace?

    Real Climate is not an “environmental group”. The authors here are all working climate scientists. It’s a science education and information effort.

    Of course, the respondents here are just random occupants of cyberspace.

    Comment by dhogaza — 1 Oct 2007 @ 12:39 PM

  24. Good question. Looks likely it’s equally bad and that would make the E”P”A’s move even dumber than it appears for immediate risk.

    All I know is what Google Scholar finds, for example

    “Recently, numerous kinetic studies on iodine compounds have been carried out and the understanding of iodine chemistry has improved considerably (e.g., Turnipseed et al., 1997; Gilles et al., 2000). As a result, in this study, we have attempted to reevaluate the role
    of iodine chemicals on the ozone depletion using the updated evaluations of iodine chemistry.”

    and a bit earlier:

    “The role, if any, that iodine chemistry plays in the polar ozone depletion episodes is not known. These events are rationalized today largely in terms of Br2- and BrCl-initiated reactions. The potential for enhancement of ozone depletions through the presence of iodine-containing molecules (I2, IBr, ICl, CH2I2, CH2IBr, CH2ICl, and CH3I) is investigated in this study….”

    Comment by Hank Roberts — 1 Oct 2007 @ 12:52 PM

  25. Hank,

    Be careful. The second paper you refer to there is dealing with tropospheric emissions of iodine-containing compounds. The ozone depletion they are referring to in that paper is occuring at the surface (in the polar spring), not in the stratospheric ozone layer.

    As far as I know, algae represent the largest (tropospheric) source of iodine to the atmosphere — probably much larger than any anthropogenic emissions. Presumably these compounds are scrubbed by the atmosphere, and don’t make it to the stratosphere where they could play a role in ozone destruction.

    The first paper you cite is interested in looking at potential direct emissions of Iodine into the upper troposphere from aircraft, and how that might affect the ozone layer.

    Comment by Sean D — 1 Oct 2007 @ 1:55 PM

  26. Sean, agreed; several of the papers I read said iodine moves up from troposphere to stratosphere over time, that was just meant as a pointer to searching for people, hoping others will find more info.

    Bromine’s far more persistent than chlorine.

    Anyone know if iodine is more persistent than bromine?

    — see Crutzen’s Nobel Prize speech; I posted excerpts here about how lucky we happened to be, in that regard:

    Comment by Hank Roberts — 1 Oct 2007 @ 3:42 PM

  27. Re 25

    The point is that we are not finding a clear and convincing science that says the large-scale discharge of methyl iodide/ iodomethane to the atmosphere is benign or beneficial.

    Consider the EPA’s risk management analysis at :
    and note that it does not address atmospheric chemistry.

    The EPA should be encouraged to include atmospheric chemistry in its risk analysis. Thinking before we release might be much easier than thinking after we release.

    Comment by Aaron Lewis — 1 Oct 2007 @ 4:04 PM

  28. As I recall the absorption spectrum of methyl iodide is shifted to higher wavelengths than methyl bromide and methyl chloride. Since the upper state is dissociative, that should translate into a shorter photochemical lifetime in the troposphere and less getting into the stratosphere. A little googling shows that the Ozone Depletion Potential of CH3I is very low and the GWP is also low, probably because of the short lifetime. From biological problems I know nothing.

    Comment by Eli Rabett — 1 Oct 2007 @ 8:09 PM

  29. Here’s how the ice melting tipping point plays out in the press:

    Comment by catman306 — 2 Oct 2007 @ 6:46 AM

  30. Bromine’s far more persistent than chlorine.

    I don’t think bromine persists any longer in the atmosphere than chlorine does. What bromine has going for it, IIUC, is a lack of relatively stable low-activity species in the stratosphere that reduce its overall catalytic activity.

    Comment by Paul Dietz — 2 Oct 2007 @ 10:17 AM

  31. Paul, do you have a source on that?
    Crutzen in his Nobel speech saidbromine was 100x as active as chlorine, and more of a problem, for several chemical reasons.
    Did you read Crutzen’s speech, or the excerpts from it I posted:

    Comment by Hank Roberts — 2 Oct 2007 @ 12:27 PM

  32. Aside — I find that methyl bromide was being argued about 12 years ago and Robert Parson cited Paul Dietz there:

    Comment by Hank Roberts — 2 Oct 2007 @ 12:31 PM

  33. Layman tipping-point Q: How far does the runnaway effect go? How has the planet recovered from warming events in the past? Can we hope for the same recovery triggers this time around?

    [Response: We are a long way from any ‘runaway‘ effects, and yes, the planet (as a whole) will recover, though the timescales to fully remove all the excess carbon we are injecting are longer than you or I are likely to care about. -gavin]

    Comment by Michael — 2 Oct 2007 @ 1:20 PM

  34. Michael (33) — My understanding is that a global warming of 6 degrees Celcius is about the same as during the PETM event about 55 million years ago. (Wikipedia has more.) This ought to be of considerable interest because all large (greater than 2 kilogram) mammalian species went extinct then.

    Eventually the so-called greenhouse gases leave the atmosphere. This takes, for some of these, are very long time. The recovery is not a trigger-like process.

    I encourage you to note the ‘Start Here’ link at the top of the page to discover some useful readings for beginners.

    [Response: I don’t think the PETM extinctions went beyond benthic ocean fauna, do you have a citation? – gavin]

    Comment by David B. Benson — 2 Oct 2007 @ 1:32 PM

  35. The question was meant as a discussion piece. I hesitate to use RC as an educational resource, because it’s purpose is not education, but an attempt to combat misinformation – and therefore not very balanced, or exhaustive.

    Comment by Michael — 2 Oct 2007 @ 2:13 PM

  36. If earlier GW events were due to excess carbon, did the excess carbon sources have to exhuast themselves before the climate recovered? Or are there feedbacks that overcome the excess carbon?

    Comment by Michael — 2 Oct 2007 @ 2:31 PM

  37. Re 34 David B. Benson “This ought to be of considerable interest because all large (greater than 2 kilogram) mammalian species went extinct then.”

    I think Gavin is correct, the PETM extinctions were largely limited to deep-sea benthic foraminifera as the deep ocean warmed and became anoxic. What wiki actually says abut mammals is:

    “At the start of the Eocene, the Earth remained warm for about 80,000 to 200,000 years. On land, there was a massive turnover of mammals, in which most of the primitive mammals that had developed since the end of the Cretaceous Period were suddenly replaced by the ancestors of most of the surviving modern mammal groups, all of them in small versions which were adapted to Eocene heat.”

    Comment by Jim Eager — 2 Oct 2007 @ 3:46 PM

  38. Re 33 Michael: “Layman tipping-point Q: How far does the runnaway effect go?”

    That depends on how much CO2, methane and other greenhouse gasses are ultimately released from both human activity and natural carbon sinks, and how far temperature rises to reach radiative equilibrium. The warmer it gets the more carbon released from natural sinks, but it’s self limiting so it can not go on indefinitely. But the warmer it gets the less dissolved carbon the ocean can hold, so the slower the draw-down will be.

    Michael: “How has the planet recovered from warming events in the past?”

    There have been different causes for past warming events (changing Milankovetch cycles increasing solar insolation and the initial warming then leading to higher greenhouse gas concentrations; massive geological disturbances directly injecting huge quantities of methane and CO2), but for all of them recovery was very, very slow.

    Michael: “Can we hope for the same recovery triggers this time around?”

    Be careful what you wish for: any “triggers” in the opposite direction will be just as disruptive, or more so. An ice age would tend to ruin your whole day.

    Comment by Jim Eager — 2 Oct 2007 @ 4:11 PM

  39. Michael, you ask a question starting with an assumption:
    “If earlier GW events were due to excess carbon”

    What particular events are you thinking of, that fit that description? Where are you getting the assumptions?

    I looked a bit and this was as close as I could get, and it’s not close — but it’s quite old, you’d want to follow cites forward of course.

    Most of the climate changes don’t seem to involve “excess” carbon, just rearrangement subject to solar/orbital variables involved, except perhaps the PETM, near as I can tell.

    This may help:

    This may be the kind of excess you’re talking about, just guessing:

    I’m not claiming any of what I found is current knowledge, check for cites and recent info. Just puzzling ober your assumption there.
    Anyhow I’d suggest you first state what you’re assuming to be true and what you base that on, and check on it.

    Comment by Hank Roberts — 2 Oct 2007 @ 4:17 PM

  40. Gavin — That’s not what Wikipedia says (but we know to take that source cum grando salis).

    P.D. Ginerich
    Environment and evolution through the Paleocene-Eocene thermal maximum
    Trends in Ecology & Evolution v. 21 #5, May 2006, 246–253.

    points out that some species did go extinct and at least one dwarfed during PETM. THe dwarfing was down to around 8 kg (60% reduction), not a mere 2 kg.

    The following abstract simply states “a turnover of North American mammal assemblages” (whatever that means).

    The following paper, by G.J. Harrington in BioObne, states “fundamental changes to mammalian communities both in North America and Europe”, citing five references.

    But any modern paleontology text ought to list Paleocene mammals which went extinct about PETM time, since no fossils are found in the subsequent Eocene. It is tempting to blaim PETM directly for this, as Wikipedia seems to have done, but it could simply be that those older species were simply out-competed by the newer forms which arose, at first quite small, by middle-to-end-PETM times.

    Comment by David B. Benson — 2 Oct 2007 @ 4:21 PM

  41. Here’s a time sequence that may help, note the positions of the continents changed quite a bit over time:

    Comment by Hank Roberts — 2 Oct 2007 @ 4:22 PM

  42. Realizing we’re way off topic here (is it Friday again yet?), I found a nice summary from a blogger I didn’t know, here:
    _________excerpt below, see link for full text and much more_______

    “… the PETM oceans. They were warm and not stratified, at least vertically. The mixing – from top to bottom – still happened, but in a way that seems wrong to those of us that grew up with our oceans and their circulation.

    It seems that there were cold provinces – if I may use that word here – in the Arctic and Antarctic. However, they were more like cool provinces since they were ice free as far as we can tell (-1.5 C is the average temperature recorded for the Arctic waters at this point). Whereas the tropical surface temperatures were approximately 8 C. To a lay person, this would seem to say that the oceans would have a normal circulation albeit a sluggish one due to the smaller differential. However, the reality is that it had a completely opposite direction than our own.

    Our oceans have the warm waters sweep to the north and then get cold and sink. The water then flows along the ocean basins and upwells in the tropics where it is once again heated and sent back to the north and south. This keeps the waters oxygenated and the bottoms of the oceans from becoming anoxic. Mostly. However, during the PETM it seems that the oceans had the opposite pattern. The upwelling was in the higher latitudes and the sinking was in the tropics. The reason being is that the water evaporation of the very warm tropical waters would produce very salty water which would sink and displace the cooler waters of the south and north along the top to the tropics by upwelling ….”
    —————–end excerpt —————-

    Comment by Hank Roberts — 2 Oct 2007 @ 4:26 PM

  43. Hank,

    “Global cooling started at the end of
    the early Eocene to the early middle
    Eocene (Figure 1). What triggered that
    cooling remains an unsolved question.”

    I guess I’m asking an unsolved question.
    …seems like an important detail.

    Comment by Michael — 2 Oct 2007 @ 5:25 PM

  44. More than a detail, but it’s a very long time ago. As that Wesleyan article says and also as Gavin points out in his China thread, the ocean cores from drilling are where the answer probably will be found, but it’s very early work yet. The Wesleyan chart shows continental drift changing rate about then with the last big collision, I think.

    There’s some discussion and interesting quotes along that line here:

    And, um, sorry for prolonging the digression, hosts. Point us elsewhere if you’d rather.

    Comment by Hank Roberts — 2 Oct 2007 @ 5:47 PM

  45. Gavin, PETM extinctions:
    “… end of the Permian Era, when an estimated 90 to 95% of all marine species, as well as about 70% of all terrestrial species, became extinct…. The warming reached a depth of about 10,000 feet (4,000 meters), interfering with the normal circulation ….
    ‘The implication of our study is that elevated CO2 is sufficient to lead to inhospitable conditions for marine life and excessively high temperatures over land would contribute to the demise of terrestrial life,’ the authors concluded ….”

    Peter Ward quoted:

    [Response: You’re confusing two things here. PETM=55 million ago, Permian/Triassic was 250 million years ago. No question about extinctions then! – gavin]

    Comment by Hank Roberts — 2 Oct 2007 @ 6:00 PM

  46. Paleocene mammals and extinctions:

    A summary with links:

    A derivative Wikipedia page linking to 32 different pages briefly describing extinct genera and species, most, but not all, in the entirely extinct order Multituberculate.

    From the summary it seems that the largest (known) Paleocene mammal weighed about 100 kilos, about like a smaller black bear. Also, “the predominent mammals of the period were members of groups which are now extinct.”

    Comment by David B. Benson — 2 Oct 2007 @ 6:43 PM

  47. Somewhat late. A lot of the Cl in the strat is tied up in ClONO2. BrONO2 is a lot less, mostly because (my guess) the tail of the absorption spectrum extends further to the red, so photodissociation is a lot more probable.

    Comment by Eli Rabett — 2 Oct 2007 @ 6:47 PM

  48. And a good summary on the PETM event:

    Thanks, Gavin, wake me up any time I need it …

    Comment by Hank Roberts — 2 Oct 2007 @ 7:48 PM

  49. Re: Response in 33

    I would define “runaway” as anything significantly greater than the best estimate provided to planners, policy makers, and other stake-holders responsible for infrastructure. Now, that is IPCC AR4 numbers. So today, I would consider any global warming/ ice melt/ sea level rise beyond what is stated in the AR4 ES to be “runaway”.

    How do you define “runaway”?

    Comment by Aaron Lewis — 2 Oct 2007 @ 9:30 PM

  50. To me “runaway,” means runaway from our human control, with “permanent runaway” (as on Venus) as special case. I’m thinking horses — they run away, and the rider cannot stop them, but eventually they get tired and stop. Or a runaway train.

    In the case of global warming today, that would mean a situation in which the initial warming caused by anthropogenic GHG emissions would cause nature to contribute (net) to greater warming in positive feedback fashion, such as by causing nature to emit a net increase in GHGs (methane clathrates and permafrost melting) and the warming leading to less albedo from less snow & ice, and many other such factors. This would be a “limited runaway warming,” since even if humans were to reduce their GHG emissions to zero, the warming would continue, not only due to the lag time, but also because nature is emitting GHGs and reducing albedo.

    Then eventually the warming would stop and the climate would return to present conditions….maybe in thousands, tens of thousands, or 200,000 years. A large chunk of life may go extinct, and many people would dies from the warming and it many many effects.

    I think my idea of “runaway” is somewhat common, though scientists are very adament about limiting the concept only to permanent runaway as on Venus. And at least one scientist suggested that we call the scenario I described “hysteresis.” That does have the implication of something going out of some bounds, but then eventually rebounded to the same conditions.

    I suppose if people really reduce their GHGs pronto and drastically we can be more assured that we may only experience “regular” or more linear global warming for a certain period (the lag time for what we’ve already emitted and will emit in the near future, plus a bit of positive feedback effects), then the climate would respond to our reductions and cool down to present conditions. I have no idea about a time scheme, but (knowing nothing) I’d guess maybe within 100 years or so. That would be my idea of a non-runaway or non-hysteresis scenario, in which the climate and nature responds to our decreased emissions — nature helping absorbing much of it (negative feedbacks), and not going off on its own positive feedback expedition into much greater warming.

    This latter is how I actually conceived of global warming until about 4 years ago, when I became aware of the greater dangers of “runaway” positive feedbacks kicking in under the hysteresis scenario. So I do think the concept of “runaway” is extremely important. Since people tend not to think much past next quarter’s profits or that Saturday night date, I really wouldn’t worry about them thinking of “runaway” as a permanent Venus-type thing. That a no-problem or only a problem for the “geological time” mind-set.

    Comment by Lynn Vincentnathan — 2 Oct 2007 @ 10:34 PM

  51. RE: How do you define “runaway”?

    Personally I think that “runaway global warming” is vague enough it should probably be retired. It is more useful for those who would wish to deny that global warming may be anything other than a minor inconvenience than it is for anyone else.

    To see what part of the problem with it is, take the example of Venus. Our sister planet received only about 15% more radiation than the earth early on in its evolution, but this was enough to result in a positive feedback loop which resulted in the evaporation of its oceans and sublimation of carbon from it minerals, resulting in an atmosphere that is rich in carbon dioxide at a temperature roughly sufficient to melt lead. Now this sort of thing could never happen on earth I am told given our moist air convection. So if this is runaway global warming, then I believe it is fair to say that it couldn’t happen here.

    But is Venus actually an instance of a runaway effect? Certainly not in the sense of process going on without limit. Afterall, it has stabilized.

    Perhaps a more useful way of interpreting “runaway effect” would be that the positive feedback has become sufficient that the process can take place largely independently of what we do. Thus for example, one we raise the temperature of the permafrost or the shallow ocean enough that large quantities of methane are released which increase global warming, resulting in a process which takes on a life of its own, this might be a runaway effect.

    But its not exactly clear that the response will be all that independent of what we do. It may be the case that we could pretty much always make it much worse by doing just a little bit more of a bad thing. (I actually suspect this is pretty much where we are today – with respect to the consequences for the next few centuries.)

    But there is another problem with this: what about earlier instances of what we might call “runaway global warming”? The Permian Triassic Extinction event, for example? We weren’t there, so it was independent of what we did, but then again, so was any other instance of global warming prior to our arriving on the scene.

    It may be the case that the further we push the system the more our “push” will be amplified, or it may be the case that we will reach various tipping points of one form or another, but I am not sure that this is what people have in mind when they think of a “runaway effect.” I believe what they have in mind is Venus – where it does not seem entirely clear that the term can be usefully employed.

    I suppose I would speak of “tipping points” where some are more significant than others. But of course there has been some discussion as to how useful that particular phrase may be.

    Comment by Timothy Chase — 2 Oct 2007 @ 11:34 PM

  52. I realize that this is OT, but I feel readers of RC might be interested in the rebuttal by Svensmark and Frie-Christensen (?sp) to the recent paper by Lockwood and Frohlich. I am sure this paper has not been peer reviewed, but I hope it will read it for it’s scientific content.

    Comment by Jim Cripwell — 3 Oct 2007 @ 8:38 AM

  53. It’s an interesting topic, because everyone can set the “runaway” bar at different levels. Not to sound negative or anything, but I think we are already past the point where we can expect to continue living life as normal even with zero emissions tomorrow (our lives and our children’s lives are already affected, and we can’t change that). What we can change is the seriousness of this future and the long term impact after we are gone.

    I don’t think we could kill the planet, our species would be extinct long before cockroaches, bacteria or algae were in serious danger. We could upset the biosphere for 100,000s of years, but I believe in time it would recover, at least our fossil record suggests that great extinctions have occurred on the planet before.

    The problem is that we are in the middle of a great extinction event right now, and noone seems to be paying attention. We could all survive on a planet 5 degrees hotter (might be able to get better use of the beach), but the changes to the environment would cause a biosphere collapse, which would result in food shortages, changes to atmospheric gases, widespread fighting over resources etc. Humans love to think we can totally control and manufacture our environment, but at the end of the day our critical needs are sustained by our natural living environment. Back in the nineties we though we could setup a biosphere and mimic the earth’s living systems, but it was a dismal failure.

    Comment by beyondtool — 3 Oct 2007 @ 9:25 AM

  54. So what is the optimal temperature for the planet? Flora and fauna have adapted to live at our current temperature and change would be bad for current inhabitants, but theoretically speaking, is there a climate ‘sweet spot’ as far as atmosphere chemistry and temperature that would be best suited for life? By coincidence are we living in such a time? Just theoretically speaking. Notice I am not suggesting we have any business tampering with global climate.

    Comment by Michael — 3 Oct 2007 @ 10:51 AM

  55. re: 52. I leave it to others much more qualified than me for the specifics but it seems amusing that the authors conveniently refer to the surface temperature trend since around 1998 as being essentially flat (supposedly in line with the solar muon signal), completely ignoring the fact that 1998 was an exceptional El Nino year which added to the global average temperature that year. Otherwise, that trend is anything but flat. The focus on 1998 is classic data trend cherry-picking, erroneously (purposely?) trumpeted throughout Denialist-land.

    Comment by Dan — 3 Oct 2007 @ 11:10 AM

  56. Jim Cripwell,
    The main problem with Svensmark’s ideas is that GCR flux is not changing overall–not during the space era and not during the past 50 years based on neutron fluxes. Presumably the rule that a cause must be extant for an effect to occur is still in force. Moreover, Svensmark’s mechanism has always been rather vague–somehow you get fewer clouds with a lower GCR flux, but there is no evidence that there is any lack of nucleation sites for condensation in the first place. Bottom line, if you look hard enough for correlations, you’ll find them whether they are there or not. That is why it is essential to have a well worked out physical mechanism as well. Anthropogenic ghg is the only such mechanism proposed to date.

    Comment by Ray Ladbury — 3 Oct 2007 @ 11:13 AM

  57. Michael, You are asking the wrong question. The planet doesn’t care. Some organisms would like it warmer, some cooler, some wetter, some drier. The question is what will conditions have to be like for us to support >9 billion humans–and the best answer to that is “predictable”. Adding energy to the climate is bound to make it less predictable, and that cannot bode well for humans on Earth.

    Comment by Ray Ladbury — 3 Oct 2007 @ 11:15 AM

  58. Re #54: [So what is the optimal temperature for the planet?]

    I think it could be argued, as James Lovelock does, that the optimal temperature for life as a whole is actually somewhat cooler than today. Cold seas are more productive than warm tropical waters. More water locked up in polar glaciers would lower the sea level, giving more usable land area. Areas like Australia, North Africa, and the part of the western US where I live were much wetter during the last Ice Age…

    Comment by James — 3 Oct 2007 @ 12:02 PM

  59. James (58) — During LGM, the last stadial, the Amazon basin was a warm and dry savanna; the tropical rain forest in Africa considerable shrunken in extent. There was a vast desert (some semi-desert) extending from the Sahara right across to Outer Mongolia; huge dust storms in North China and also where I live. The Mammoth Steppe extended from Spain across Europe to Siberia and beyond to Beringa and interior Alaska.

    While I agree that somewhat colder is better, not that much colder, please…

    Comment by David B. Benson — 3 Oct 2007 @ 12:10 PM

  60. We’re already in the middle of a major extinction event caused by the landscape changes associated with hosting 6 billion plus humans on Earth. Even without AGW, we are on track to lose a lot of the Earth’s species. I’ve seen extinction numbers tossed around, but most seem to settle on 30 to 50% of all named species, without AGW’s negative effects. See any of E.O. Wilson’s work for good references on this. I think it will be much worse than most, but hey, my glass broke a long time ago (not even half empty). And many of us won’t be spending more time at the beach as we won’t have beaches to go. Our Texas beaches required centuries (at least) of stable sea levels to accumulate and submerged barrier island/beach systems 20 miles offshore in the Gulf are testaments to past rapid sea level rise episodes. My point is this: when you realistically look at the mechanics of long term species survival (where are they now, what they will be faced with, etc.) or coastline processes; it is easy to see that most AGW projections tossed out by the general press or even mainstream conservation groups are way to rosy. One last example: much of NA’s migratory waterbirds such as whooping cranes, waterfowl, herons, ibis, etc. reside or winter in Gulf of Mexico fringing wetlands. Often these are in National Wildlife Refuges. There are at least 400,000 acres of federal and state refuges on the Texas coast alone. Most of this preserve acreage is less than 1 meter above sea level. The coastal wetlands that host these birds took thousands of years of nearly stable sea levels to form. Draw your own conclusions but I think the consequences of AGW for fish, wildlife and plants etc. are going to be catastrophic.

    Comment by Andrew Sipocz — 3 Oct 2007 @ 12:26 PM

  61. Ray, I was trying to stay away from the AGW vs Denier debate but, I’ll take the bait as usual.

    Adding energy to the climate is a fact of life. No matter what we do we will have a carbon footprint. To think that we could reduce total human impact enough to bring the climate back to something resembling a natural cycle is not realistic. And a natural cycle is still fraut with variability. Saying we need to stop adding energy to the climate is a marginal solution to a significant problem. If we want predictability we are going to have to become masters of our domain, and begin devising massive geoengineering solutions. I think this will eventually happen, and unfortunately will include dead ends and catastrophic failures.

    Regardless, you will not gain support from most people by suggesting a marginal solution to a significant problem. And considering a best case scenario where everyone sacrifices and participates, we will still have warming in our future.

    I know I have said all of this before, but if someone were to seriously take on this issue, it would be the biginning of winning over people like myself.

    Comment by Michael — 3 Oct 2007 @ 12:52 PM

  62. Hi to all,
    Just wonding if any of you have come across this;

    The 3 guys from wales, 1 Organic Chemist and 2 Engineers.
    They have found away to capture CO2 and release it to make Oil-Methane Gas-Fertilizer, in short recycling the CO2 we generate into energy.

    Intersting prospect I thought, Radical thinking on a major scale?

    Look forward to any comments.

    Comment by Welsh Citizen — 3 Oct 2007 @ 1:26 PM

  63. Welsh Citizen (62) — The Greenbox appears to be innovative and, at the least, could be used to capture caron dioxide and nitrous oxides for sequestration deep underground.

    As for feeding to algae, Biopact is not impressed with the results so far and sees little prospect for improvement:

    We may hope they are wrong in their negative assessment.

    Comment by David B. Benson — 3 Oct 2007 @ 1:40 PM

  64. I’d like to re-ask the question I asked in respl. #2, whenever Dr. Shindell or someone knowledgeable can answer what the experiment was actually trying to do.

    Comment by Hank Roberts — 3 Oct 2007 @ 1:45 PM

  65. Re 54 Michael: “So what is the optimal temperature for the planet?”

    That’s a meaningless question. Life has adapted to exist over a rather large range of temperature and climatic conditions throughout Earth’s history, including some that would be lethal to most of life as it exists today.

    The real question is: What is the ideal temperature for life as it exist here and now, including current humans and their civilizations?

    You go on to answer this question yourself:
    “Flora and fauna have adapted to live at our current temperature and change would be bad for current inhabitants.”

    Which includes us and our civilizations.

    “By coincidence are we living in such a time?”

    We are living in the time and conditions that we evolved in, period.

    Comment by Jim Eager — 3 Oct 2007 @ 1:54 PM

  66. Michael,
    I don’t believe I said we should go back to the stone age. I merely said that if we add energy to the climate it will become less predictable. Predictability is a really good thing, especially if you are a farmer–or a consumer of farm produce or of water…
    This is not a matter of “going along” or not. This is physics. It is a mathematical certainty that if we keep going down the road we’re on, we will make things very, very difficult for our descendents. You either accept the evidence and resolve to struggle to change the current path or you live in denial and consign your descendents to a world none of us would want to live in.
    So if you have concerns about the effects of mitigation on the economy (and you should, because we won’t succeed without a strong economy to fund research into mitigation), then I would suggest you start working for common sense measures that buy us time and allow smart people time to develop solutions to our predicament.

    Comment by Ray Ladbury — 3 Oct 2007 @ 2:20 PM

  67. > Greenbox

    Nah. If they had a way to hold CO2 in such a dense form, the carbonated beverage companies would be all over this just to reduce the cost of shipping big compressed tanks of gas.

    If there were an “intert” form of CO2.

    If something that looks like a furnace filter could hold in such a dense state and release it later, at no great energy cost.

    Could they have Maxwell’s Demons working in their boxes?

    Comment by Hank Roberts — 3 Oct 2007 @ 2:24 PM

  68. Jim Eager (#65) wrote:

    Re 54 Michael: “So what is the optimal temperature for the planet?”

    That’s a meaningless question. Life has adapted to exist over a rather large range of temperature and climatic conditions throughout Earth’s history, including some that would be lethal to most of life as it exists today.

    The real question is: What is the ideal temperature for life as it exist here and now, including current humans and their civilizations?

    The way that I sometimes like to think of it is that just as our civilization hs a great deal investment and infrastructure which is largely grounded in the the assumption that the climate would remain stable, other species and entire ecological systems have done much the same, and when the assumption gives way to climate change a great deal will be lost. (Sorry – I like economic analogies.) Entire cities (from their buildings, to their sewers to their subway systems) were laid down on the assumption that the sea level wouldn’t rise several meters in any given century.

    Domesticated species of plants were breed over centuries with the assumption that there would exist a certain mix of soil, precipitation and temperatures – and we will have a great deal of difficulty adapting these species as conditions change. Fish, coral and the ecological systems in which they participate have evolved with the assumption that the acidity and oxygen levels of the ocean would remain relatively constant.

    But are already changing quite rapidly in the northern latitudes. Places like Australia and California are experiencing longer and more severe droughts. In many parts of the world, some of the richest ecological systems based around coral reefs are already under severe strain. And it is not simply the existence of climate change or its magnitude which we or other life must worry about – but the rate of climate change – which is (as I understand it) over a hundred times faster than anything which we have experienced since the dawn of human civilization.

    PS The above might not be that well thought out – just trying out my new laptop… (I even like the feel of the keyboard!)

    Comment by Timothy Chase — 3 Oct 2007 @ 2:29 PM

  69. Wayyy OT here, but this is comment >60 so I think I’m not out of line(?). Has anybody seen Stu Ostro’s post at titled “A CONNECTION BETWEEN GLOBAL WARMING AND WEATHER”?

    Comment by Pete DeSanto — 3 Oct 2007 @ 2:33 PM

  70. Jim,
    The impression I get, is we are living in optimum or slightly warmer than optimum temps. Warming causes more extreme weather, hurricanes, droughts, etc. Slightly cooler would mean more benign weather patterns, while still being warm enough to keep most of the planet green.

    Another impression I get is most environmentalists are more concerned about harming the planet than they are about harming civilization.

    Comment by Michael — 3 Oct 2007 @ 2:38 PM

  71. “By coincidence are we living in such a time?”
    We are living in the time and conditions that we evolved in, period.
    Comment by Jim Eager

    Except that we’ve cut down so many of the forests that existed while we evolved. The optimum climates for large forests full of trees are the optimum climates for prehistoric man. And now we’ve learned to use fire, and mechanical energy that uses fossil fuels, to add CO2 and other pollutants to the atmosphere. We no longer live in the optimum climates for our species. Severely curtailing the use of fossil fuels, using every available non-fossil fuel alternative (weighing in the complete carbon footprint of the alternative fuel) and the planting of many billions of trees would seem very prudent measures at this time. We all want to see our species and civilization survive another millennium, don’t we?

    On the other hand, someone cut down the last tree on Easter Island, didn’t they?

    Comment by catman306 — 3 Oct 2007 @ 2:55 PM

  72. Michael,

    According to some recent NASA estimates I saw, we are talking about a rise in temperature along the east coast of about 5F without any additional carbon dioxide vs 10F with Business As Usual – by the 2080s. And thats just the east coast. And it is worth keeping in mind the fact that each additional degree is going to be harder on the economy than the preceding degree. In terms of the world economy and various ecological systems, the damage will be roughly an exponential function of the change in temperature. (Something similar is probably true regarding the rate of change.)

    According to the analysis of a former leading economist from the World Bank, the consequences of BAU will be roughly comparable to that of the period from World War I to World War II. I myself strongly suspect that we are talking about a crisis that will be considerably deeper and of greater duration than the Great Depression. The longer we put off changing our trajectory the harder it will be to do so with the growing economies of China, India and other developing nations as become more invested in current technologies.

    Comment by Timothy Chase — 3 Oct 2007 @ 3:11 PM

  73. I think # 53 makes a good point: “We could all survive on a planet 5 degrees hotter (might be able to get better use of the beach), but the changes to the environment would cause a biosphere collapse, which would result in food shortages, changes to atmospheric gases, widespread fighting over resources etc. Humans love to think we can totally control and manufacture our environment, but at the end of the day our critical needs are sustained by our natural living environment.”

    It’s not so much coping with days and nights that are on the whole 5 degrees hotter (stay hydrated, stay in the shade, get an AC, go to the library), as it is all the impacts, the storms, food loss. And Mark Lynas’s SIX DEGREES pretty much spells out the hell we would be in at 5 degrees. He also writes (if I remember) that if we get to 3C degrees warmer, then that will tip us into “runaway” positive feedbacks that will get us (despite all our efforts to reduce our GHG emissions) up to 4 degrees, which in turn will push us up to 5 degrees, then 6 degrees — over a long time span, to be sure, but it would probably be a done deal.

    It might have been better to have written “we could EACH survive…” since certainly not ALL will survive. That’s the whole point of mitigating GW, so that we all or most can survive.

    Comment by Lynn Vincentnathan — 3 Oct 2007 @ 4:19 PM

  74. One question I never see addressed:
    Does depletion of stratospheric ozone,
    leading to increased UV in the troposphere,
    increase ground-level warming? Thank you.

    [Response: No. It leads to a slight cooling. This is included in the classic IPCC forcing diagrams. The increase of tropospheric ozone due to ground-emitted pollution is however a significant warming effect, but that is not related to stratospheric depletion. – gavin]

    Comment by john — 3 Oct 2007 @ 5:43 PM

  75. Re 70 Michael: “Jim, The impression I get, is we are living in optimum or slightly warmer than optimum temps.

    We definitely are living during the peak of the current interglacial, but that peak is eventually destined for a long decent into the next glaciation, unless the current warming is sufficient to disrupt the cycle that has held for the past 650,000 years. We know it’s not impossible as there have been long interruptions of the glacial cycles in the past.

    Michael: “Warming causes more extreme weather, hurricanes, droughts, etc. Slightly cooler would mean more benign weather patterns, while still being warm enough to keep most of the planet green.”

    But given enough time, life as a whole and even some individual species would evolve and adapt to those climate states, which would make those states “ideal” for those adapted species. But as Tim said, the current rate of change will outstrip many species’ ability to adapt, quite possibly including our own.

    Michael: “Another impression I get is most environmentalists are more concerned about harming the planet than they are about harming civilization.”

    Some do, I’m sure, but I consider myself an environmentalist and I recognize that there is really not much we can do to harm the planet or even life itself beyond its ability to recover, it’s just that we may not be around to see how great the change is because we most certainly can change the environment and climate system sufficiently to threaten our own survival in that environment, not to mention the survival of civilization as we know it.

    And re 71 catman306, yes, I realize that we ourselves have substantially altered the environment and climate from what it was when we first left the forest for the savanna (I thought that would be understood as a given), but environment and climate have also been altered radically by natural changes over the past 2-3 million years of our evolution. It is civilization that has evolved in the most recent relatively stable period.

    Comment by Jim Eager — 3 Oct 2007 @ 8:47 PM

  76. RE 72
    Your optimism in the face of such temperature changes borders on irrational exuberance.

    At such rates of temperature change, agriculture does not have an experience baseline for the prediction of crop rotation and fieldwork schedules. Suddenly, localities have the climate for new crops, but not the infrastructure, to produce and store such crops. Look at the recent bumper crop of wheat in parts of Colorado that ended up sitting in piles in the open because the infrastructure to put it in storage was not in place. While in some traditional wheat growing areas, such infrastructure sat idle as a result of drought.

    The critical difference between GW and the Dustbowl Years was that, in the 1940s, much of that dust bowl went back to being good farmland for the same crops that it produced prior to the Dustbowl Years. Certainly, farming methods had to change to prevent a reoccurrence. Still, the heat of the 1930s was a matter of a few hot years, and then farmers were back to a familiar climate for which they had experience. With GW, we cannot expect that return to normalcy.

    The faster the rate of climate change, the more agricultural crop failures we can expect. The more absolute change in climate, the more likely crop failures will increase exponentially. The more crop failures, the more drag on the economy. Food is going to get expensive, to a degree that will dismay modern economists, shock the public, and force politicians from office.

    Cotton is the crop that consumes more pesticides, fertilizer, and fuel than any other single crop. Also, cotton has specific water requirements. Expect a change in climate to impact cotton production. A surprising amount of synthetic fibers are produced very near sea level, or in areas where critical infrastructure is at or near sea level. In a feedback loop, the fuel, fertilize, and pesticides for cotton farming are commonly made near sea level. Moreover, sea level rise will cause saltwater intrusion into prime cotton growing areas. Thus, expect small changes in sea level to have a disproportionate impact on fiber production. Expect clothing to be far more expensive.

    Walk through a local drug store, and look at how many products on the shelves contain organic chemicals made in a chemical plant that is within a few feet of sea level. Automotive supplies are made in sea level plants. My computer uses parts from such plants. Repair parts used by cell phone service providers come from such plants. Airplanes and their repair parts come from such plants. The two largest airports near me are within a meter of sea level. Finally, a rise in sea level would play havic with a great many cities’ underground utilities. Certainly, all of these facilities can be flood proofed or moved. However, that is a large capital investment that managers and stakeholders are going to delay making until after global warming intrudes into their planning horizon.

    The usual problem with a runaway horse is not how far it goes, but that surprised riders or bystanders are injured in the first mad dash. The problem with global warming is not that it is coming in the distance, but that it is catching us off-guard and unready. I expect sea level change to be episodic, and that the first event will change our paradigm. We still have too much infrastructure and too many manufacturing facilities at sea level. We have too many people living in lowland areas. Our climate and weather prediction systems are too crude to help farmers plan multi-year crop rotation schedules in an era of rapid climate change. The data quality of our sea level predictions is inadequate as a basis of design for engineering.

    In short, we do not have a plan. We do need to stop emitting greenhouse gases. We also need to deal with the ongoing effects of the greenhouse gases we have already emitted. We need to start mitigating impacts on our economy. And, I do mean OUR economy. The developed world could lose everything to GW. So could China, India and the other developing nations. We can only win this game if everybody works together, so that everybody wins. A group of nations can spoil it so that nobody wins, but no nation can win without the everyone’s cooperation. On the other hand, wining will be a relative thing, and any win will involve great effort and much loss.

    Comment by Aaron Lewis — 3 Oct 2007 @ 10:24 PM

  77. Re #61: [Adding energy to the climate is a fact of life. No matter what we do we will have a carbon footprint. To think that we could reduce total human impact enough to bring the climate back to something resembling a natural cycle is not realistic.]

    The energy humans directly add to the climate is insignificant. I don’t recall the exact figures (you can probably find them here if you’re better at framing search terms than I am), but IIRC its several orders of magnitude less than the additional solar energy trapped by a relatively small change in CO2.

    It’s certainly possible to envision a world that could sustain present populations & living standards without emitting significant amounts of CO2. It’s even possible to work out the technical ways of getting there without invoking too much hand-waving. The only real problem lies in getting a sufficient number of people to go along.

    Comment by James — 3 Oct 2007 @ 11:07 PM

  78. Thanks for answering, Gavin. What does “the increase of tropospheric UV due to ground-emitted pollution” mean?

    [Response: Sorry, I meant ozone. I corrected the comment. – gavin]

    Comment by john — 4 Oct 2007 @ 12:33 AM

  79. Gavin- Does an increase in tropospheric UV from stratospheric ozone depletion lead to an increase in tropospheric ozone? Thank you.

    Comment by john — 6 Oct 2007 @ 11:58 AM

  80. I appreciate the collected links for working to understand ozone chemistry, and will investigate them. I was reminded of agriculture’s many millions of pounds use of methyl bromide to sterilize soils, and the ban of it but repeated government agency waivers of phaseout. Alternative methods of soil treatment and crop management as well as development of substitute chemicals are difficult vectors to pursue, but the impetus to ban methyl bromide for such uses has been underway for decades in our prominent ag producing state in the US. At the time I last studied the state EIR monograph for methyl bromide, granary fumigation and even structural insecticide use of methyl bromide were prominent though second tier sources for its release into the atmosphere. Our state court mandated an EIR for the use of pesticides of all stripe; the overseer of the development of separate monographs for each of the seven most widely used compounds continues to have an agrichemical toxicity law practice, though now situated in the eastern part of the US; the methyl bromide EIR monograph was about 200p.; his current website references none of his firm’s prior work in that EIR, but is there: In the comments about iodine I was reminded of that halogen’s use in the airplane seeding of clouds to cause rain. With respect to the statements about population control and seeking a way to step outside the inertial box in which we have our civilization, to glimpse at the wide implications of tipping points or “runaway” interactions, I recalled seeing an outsize experiment conducted by a graduate seminar student in a chemistry lecture I attended; the apparatus was much larger than the prepackaged elementary experiments in fun science, resulting in enhanced impact on the observers; what the advanced chemistry student had assembled was a double Ehrlenmeyer flask connecting many liters of ammonia solution in what is known as the ammonia fountain; a consumer grade animation is shown there: with tiny flasks. The concept was the feedback loop drove the reconstitution of the solution as the color tinted solution traveled in waterfall resembling motion between the reservoirs, until equilibrium and binding of the molecules which fueled the reaction. Rocket motors operate on similar principles, except the burn is a one-time event only. The ammonia fountain demo was a bit risky, it seemed, as the gifted chemist who assembled the components, like the students in attendance simply had to watch while the process, once launched, traveled to endstate.

    Comment by JohnLopresti — 7 Oct 2007 @ 3:28 PM

  81. and Robert Parson cited Paul Dietz

    Cited me as an example of someone who was convinced by the evidence in spite of possibly contrary political preconceptions. I feel good about that, but, really, reading the relevant papers in the atmospheric physics/geophysics literature made it difficult to come to any other conclusion.

    It was good training, though, and I now recognize the same general kind of cognitive errors in the denialists this time around. With ozone and CFCs, the denialism eventually migrated out to the manifestly lunatic fringe and left serious public debate. I suspect the same process is at work with fossil fuels, but the economic interests are much larger so it will take more time.

    Comment by Paul Dietz — 9 Oct 2007 @ 8:30 AM

  82. As a lazy layman, not a scientist, not having researched the above links,
    all I can do is share my ignorance and mistrust of modern atmospheric
    science. The cutting edge of science seemed to abound abound with
    reversals and flip-flops, as I remember from the articles in My Weekly
    Reader. This I now see is part of the process of science, peer review.
    Atmospheric science has come a long way since Carl Sagan. It has come even
    further since investigators pointed spectrometers at the sky and found
    sodium lines. This unexpainable discovery was promptly dismissed as error.
    In fact, ocean sloshed salt became airborn and ionized. How is the
    associated chlorine dismissed by today’s science? They claim it recombines
    before it passes the tropospheric barrier. I would want a better explaination
    of why oceanic chlorine is less depleting than man made CFC’s. Perhaps the
    sugested diminished Cl2O2 pathway and its resulting stability amounts
    to sucking the oxygen out of the air. Plus, what does OD have to do with
    global warming? I guess I’ll have to go see that Al Gore movie.

    Comment by Greg Weisbrod — 10 Oct 2007 @ 3:04 PM

  83. Greg Wiesbrod posts:

    [[ I would want a better explaination
    of why oceanic chlorine is less depleting than man made CFC’s.

    Because oceanic chlorine is water-soluble, and rains out before it reaches the stratosphere, while chlorine in CFCs is water-insoluble and survives to be lofted into the stratosphere by atmospheric turbulence.

    Comment by Barton Paul Levenson — 11 Oct 2007 @ 8:13 PM

  84. In fact, ocean sloshed salt became airborn and ionized

    The conventional scientific theory is that the atomic sodium in the upper atmosphere (high above the stratosphere) comes from micrometeorites, not a terrestrial source (and the sodium atoms are neutral, not ionized, otherwise they wouldn’t show those strong yellow lines.) The contrary view was being pushed by the pseudoscientists back before they lost the CFC war.

    The source of chlorine in the stratosphere is know to be mostly from CFCs and related compounds, btw, since we’ve detected the other breakdown products of there (HF, COF2, etc.) in consistent amounts. These fluorine species have no significant natural sources.

    Comment by Paul Dietz — 12 Oct 2007 @ 1:43 PM

  85. > and Robert Parson cited Paul Dietz

    Yep. I appreciate that you’ve been thinking hard for a long time in public about science. Thank you.

    Comment by Hank Roberts — 13 Oct 2007 @ 11:05 AM

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