RealClimate logo

Unforced Variations: July 2012

Filed under: — group @ 3 July 2012

Have at it.

561 Responses to “Unforced Variations: July 2012”

  1. 51
    David B. Benson says:

    Jack Roesler @25 — Yes, less cold nights are a (readily calculated) prediction from increased so-called greenhouse gases.

  2. 52
    David B. Benson says:

    Anna Haynes @47 — Unfortunately your third paragraph is not sufficiently clear to attempt to formulate a reply.

  3. 53
    Patrick 027 says:

    Re my 30: While the ECS in terms of temperature would have a different slope (and a range of temperatures exist for which the ice line remains at 0 or 90 deg latitude), it would pass the 1/0 threshold at the same points.

    Clarification: the equilibrium climate in terms of temperature would have a different slope, which would be the ECS.

  4. 54
    Chris Colose says:

    JCH, MARodger, Patrick:

    Regarding Andy Lacis’ discussions of the high CO2 limit, perhaps I can shed a little bit of light on this. I’m doing my PhD-related work at GISS over the summer (though on a different topic) but have had some private discussions with Dr. Lacis on this, and am trying to help piece together a side project on similar sorts of exploratory climate related topics, time-permitting.

    Some of the results referred to by Andy are based on so far unpublished work that was presented at the Bert Bolin Symposium in Sweden this year. I was not there, but I’ve seen the notes from his presentation (I believe Ray Pierrehumbert also gave a talk).

    Andy’s “Proto-runaway” results in the high-CO2 limit are based on Gary Russell’s model at GISS (see and see e.g., C480cR.S for the radiation code), which I guess you can think of as a simpler version of ModelE. Descriptions are available online, though someone like gavin will have to fill in the details.

    The radiation flux calculations based on the correlated k-distribution method (Lacis and Oinas, 1991) in the radiation codes of GISS are typically accurate to within a couple percent from line-by-line results, and accurate radiative transfer serves as the foundation for understanding the response to changes in CO2. Simple “logarithmic rules of thumb” work only in a narrow range.

    Gary’s model is a bit more accessible than a super-complex GCM in terms of going back and checking where things can be fixed if the model crashes. Once you get to climates far away from the present, you need to worry about the model blowing up if something weird happens. Andy’s Science paper that zeros out the non-condensing GHGs is based on the GISS 2×2.5 degree AR5 version of ModelE with a Q-Flux ocean; the experiment comes to halt eventually if increasing sea-ice thickness hits the ocean bottom, in which case you can get something like a divide-by-zero in the ocean heat transport somewhere in the fortran code. If you’re near something like a runaway greenhouse regime, a complex model like ModelE won’t be suitable because you’d need to start changing a bunch of fundamental things like the thermodynamic gas constants, and you’d need a bunch of people to modify their sub-routines in the model code, etc.

    There was an experiment performed with GCM-calculated 256xCO2, with an interactive 100m ocean for faster convergence to equilibrium. Global mean temperature becomes 70 C and cloud cover decreases, shifting predominately to high clouds, with surface air specific humidity increasing by nearly an order of magnitude. (As usual, clouds pose a large uncertainty in climate sensitivity, but on the cold end they have a pretty unambiguous warming effect since the albedo effect of clouds over ice is less important for climate than clouds over a relatively highly absorbing surface). Increasing cloud height generates a stronger greenhouse effect (Dennis Hartmann has some work on this relevant for the modern climate, which pretty well explains why the longwave component of cloud feedback tend to be positive).

    From more of a theoretical end, I’ve discussed climate feedbacks here and the snowball ice-albedo feedback here.

    The paper by Kasting and Ackerman also does a high-CO2 experiment, though it’s worth noting the limitations of radiative transfer modeling in dense-CO2 climates like might have occurred on early Earth or early Mars (e.g., Halevy et al., 2009, Radiative transfer in CO2-rich paleoatmospheres, JGR; Wordworth et al., 2010, Infrared collision-induced and far-line absorption in dense CO2 atmospheres, Icarus) due to uncertainties in collision-induced absorption and sub-Lorenzian behavior of spectral line away from the line center. 40,000 ppm is not too large in that sort of context though.

  5. 55
    Anna Haynes says:

    Hello David B.B. #51, and apologies.

    #47 3rd para expansion: The impression I get from reading (a very few) “climate future” docs meant for planners, is that they take the climate models’ outputs as being what they need to plan for, in order to have a satisfactory outcome. But if Nature’s going to be making a habit of throwing things at us of a quality/quantity/intensity that the models didn’t warn us about, then “expect unpleasant surprises” should be (but isn’t yet?) part of their – and our – planning.

    Does that help?
    (so the Q is, is there a statistical way to compare models’ outputs against our wild/weird/”sticky” weather, & see if it’s “outside the bounds”, statistically speaking; which is the kind of thing I took Tobis to mean, by his “stodginess” comment (link); “models have always had kind of a stodginess to them; … they do not deliver extreme events at the rate and extent that the real system does”; and “At some level of climate change models look likely to fail to track the general weirdness level”)

  6. 56

    46 Susan, I welcome your insight, I rather challenge others to observe the same thing, its very hard to convince about a new (in this case old) phenomena. I suggest reading my blog and website on the subject. And unlike most, I hand wave not in frustration but pointing finger towards the sunset horizon. Tale a look, and make the necessary repetition, I cant convince any better than by making you look at the sky! There was no forest fires during winter when these streaks were observed.

    43 Secular, “Is it any wonder that the screeching of the deniers that there is NO LINK between global warming and the onslaught of dangerous and destructive weather events grows more hysterical every day?”

    No its not, politics has been infecting the Climate Change dialogue amongst the experts about the subject, for the intent of poisoning the field, rendering climate science unappealing to scientists and especially to the voter audience. To improve against this we must remove the politics, leave it to politicians, and shed light on those in error having influence over them. Contrarians love the confusion about AGW, but they are highly incapable climate experts, not in diagnosing. especially not in projecting future trends.

  7. 57
    David B. Benson says:

    Anna Haynes @54 — I generally believe that Michael Tobis knows what he is writing about. In any case the climate models model climate, not weather. So climate models alone are not going to be that helpful in predicting extreme weather events. For some aspects a paleoclimate prespective is useful; read “Six Degrees” by Mark Lynas:

    In general planners need to recognize that extreme weather events such as high winds and tremendous downpours will be more likely. Predictive studies of such do appear in the literature but possibly are not adequately drawn to the attention of the planners.

    Possibly worse are the northerly march of the arid zones. This is a prediction from climate models. We have seen the example of Texas and nearby areas from last summer; severe agricultural losses. This summer the drought zone appears to be much more extended. The climate models suggest such conditions will be much worse (and more northerly) in the future.

  8. 58
    simon abingdon says:

    #44 Hank Roberts says “This may be the oldest proverb in the English language”.

    “When the blind lead the blind, both shall fall into the ditch”. Good point Hank.

  9. 59
    Patrick 027 says:

    Re 53 Chris Colose – thanks.

    Re my 30 – just noticed the snowball Earth link I gave earlier: “Molecule for molecule, CH4 is ~30 times more powerful as a greenhouse gas than CO2,” – this being the radiative forcing…

    (PS GWP is based on forcing over time, and so CH4’s oxidation reduces the ratio – although an individual CO2 molecule actually has a shorter atmospheric residence time, the lost molecules keep getting recycled back into the atmosphere so the perturbation lasts longer (the residence time of combined reservoirs is longer) – so I’m guessing the GWP ratio jumps to a higher value for a few years and then decreases below 30…? Whereas if there’s much less oxidation of CH4, the ratio stays higher for a long time?)

    This 30:1 ratio (or 24:1? – I’ve seen different values) is appropriate in the discussion of AGW or similar situations, but it depends on the amount of CO2 and CH4 – decreasing CO2 or increasing CH4 reduces the ratio. Very interestingly, if equal amounts (by volume or moles) of CH4 and CO2 are present, oxidizing CH4 to CO2 actually should cause warming because CO2 is stronger (for otherwise sufficiently familiar conditions, at least).

  10. 60
    Patrick 027 says:

    oxidizing CH4 to CO2 actually should cause warming – well, that’s setting aside redistribution of that CO2 among the atmosphere and ocean, etc; thus depends on the time scale and just how much stronger a molecule of CO2 is compared to CH4 when they are present at equal amounts (which I don’t know offhand).

  11. 61
    Chris Colose says:

    Patrick- I’d check out Ray P’s Neoproterozoic review paper. He builds a rather convincing case that methane has a rather limited radiative role in the snowball Earth problem, for precisely the reasons you mention. It’s not very surprising, but a point that I don’t think is well appreciated by the community. It’s even worse in anoxic atmospheres, because you start to build up haze layers at high methane concentrations that produce an anti-greenhouse effect like on Titan.

  12. 62

    wili wrote in 4:

    Could we devote some time here talking about recent weather events in the US and abroad? The recent dericho event in the East seemed rather extreme. Has that happened before? Have such events increased in frequency, intensity, size?

    What we saw this weekend wasn’t simply a derecho but a super derecho, what you may see called a land hurricane by some.

    Please see:

    Touching upon the strength of the storm. Wind gusts were reported at up to 91 miles per hour – that’s equal to a category one hurricane. Most of the deaths caused from the super derecho were because of falling trees.

    Derechos usually strike the lower midwest every year, with the last major derecho occurring in May of 2009. In May of 2009 over 45 tornadoes were spotted due to the sustained wind gusts. During this storm, only one report of a tornado had been sighted.

    Super Derecho Photos: Land Hurricane Slams 700 Miles of the US, Leaving Path of Destruction
    by Gregory Gomer, 2 July 2012

    The May 2009 derecho was a super derecho, and it was the first.

    Please see:

    The May 8, 2009, derecho, however, was in a league of its own. An intense vortex and eye-like structure similar to what forms at the center of tropical cyclones (the generic name for tropical storms and hurricanes) appeared in the bow echo, said study team member Clark Evans of the National Center for Atmospheric Research, in Boulder, Colo.

    The storm gained strength as it moved across Kansas in the early morning, spinning off 18 tornadoes and packing wind speeds from 70 to 90 mph (115 to 145 kph) when it hit Springfield, Mo. The super derecho plowed a path of destruction through the state about 100 miles (62 kilometers) wide, crossed the Mississippi River with 90 to 100 mph (145 to 160 kph) wind gusts and blew through Illinois before dissipating at that state’s eastern border.

    Huge Windstorm Spawns New Classification: ‘Super Derecho’
    by Brett Israel, 12 September 2010

    As such, there have been only two super derechos ever recorded, both of which occured since 2009.

    Derechos are warm weather storms. There was another recent, more or less unprecedented storm, but it was cold weather.

    Please see:

    But let’s start with meteorologist Jeff Masters, who puts this staggering superstorm in context and examines the climate change angle:

    The mega-storm reached peak intensity late yesterday afternoon over Minnesota, resulting in the lowest barometric pressure readings ever recorded in the continental United States, except for from hurricanes and nor’easters affecting the Atlantic seaboard. So far, it appears the lowest reading (not yet official) was a pressure of 28.20″ (954.9 mb) reduced to sea level reported from Bigfork, Minnesota at 5:13pm CDT.

    Masters: “Strongest storm ever recorded in the Midwest smashes all-time pressure records”, by Joe Romm, 27 October 2010

    Like the super derecho of 2009, the weather bomb of 2010 had a hurricane’s eye.

  13. 63
    ozajh says:

    Mark Ryan @ 28,

    I believe “forcing” might be a crossover term from agriculture. I’ve certainly seen it used as shorthand for “force-feeding” in a book published before 1970, and I have a vague memory of seeing it used with respect to using artificial means such as cloches to start a crop earlier than natural conditions allow.

  14. 64
    ozajh says:

    If CO2 reached 4%, the temperature would be the least of our worries. Don’t humans suffocate at levels lower than that?

  15. 65
    Jim Larsen says:

    32 Geoff linked to: Climate models don’t yet account for increased forest fires.

    From a scientific standpoint it makes perfect sense to work on the puzzle a piece at a time while leaving future work blank. The default is to replace “not well known” with 0 +- 0, with a caveat noting the hole in the model. This creates a problem when scientific results leave the purely scientific realm. Experience has shown that the caveat will be completely ignored, which means that pubic perceptions and policy have been misinformed in a systemic way. This is primarily important in communications which purport to sum things up, like sea level rise or global temperature. The classic example of this type of communication failure was the sea level rise estimate which left out ice melt completely.

    One solution would be to replace important “not well known”s with an estimate in any public communication, and nowadays that includes peer-reviewed papers. Keep the paper as is but add a bit afterwards about the biggest remaining unknowns and how they interact with the work. The level of detail and rigour could be very low and still accomplish the purpose.

    James Hansen has become a master of writing peer reviewed work for public consumption. He knows that the audience is no longer just other scientists. If I were to write a scientific paper, I’d try to incorporate many of his techniques.

  16. 66
    Geoff Beacon says:


    I do appreciate your ability to search Google Scholar and find useful peer reviewed papers.

    Perhaps an important area missing from the peer-reviewed literature is negative results. Not many scientists publish papers saying, “I just don’t know” or” we can’t do that”

    Could you accept, as a challenge, my earlier comment #32? Can you find peer reviewed papera about the missing feedbacks in climate models, particularly forest fires?
    I would be happy, very happy, if you won this challenge.

  17. 67
    MARodger says:

    ozajh @63
    The 4% CO2 (40,000ppmv) level appears for a number of different reasons.
    The value was introduced into this threat @7, where 4% is described as the level resulting “if all the CO2 that is locked up in the carbon reservoirs was released into the atmosphere.” This presumably means all fossil fuels. All planetary carbon is 5,000 times that figure (see last link @30 above.)
    4% is also the level found in exhaled human breath.
    And 4% is the “Immediately Dangerous to Life or Health” (IDLH) concentration. (See Revised IDLH here. You would not suffocate until far higher levels. Below suffocating levels the CO2 will probably do for you by other means. According to here, Exposure to very high concentrations (e.g. exposure to 6% volume CO2 for several minutes or 30% volume CO2 for 20-30 seconds), has been linked to permanent heart damage, as evidenced by altered electrocardiograms. Concentrations greater than 10% are capable of causing loss of consciousness within 15 minutes or less.

  18. 68
    Flakmeister says:

    @Secularanimust #45

    The PDF link is dead… That is a great and timely quote and it would be nice to have the source….

  19. 69
    Radge Havers says:

    ‘Forcing’ does seem like an odd term. I checked my OED (not thoroughly–you need a microscope to read it) and there are extensive entries for ‘force’ and related variations. There does seem to be an agricultural connection, particularly in Australia and New Zealand (‘forcing dog’ in sheep herding, for instance). There is also mentioned a hydrostatic ‘forcing-pump’ from the 1700s. The term seems to have francophone overtones perhaps connected to the english use of the term ‘forcement’ with the sense of strengthening or encouragement.

  20. 70

    A [personal] example of damage from a derecho occurring in 2011:

    This wasn’t a super derecho, nor was it one of the worst ever, though in South Carolina it received the nickname “Great Derecho” for its severity at the state level. Costs were nevertheless quite significant; our insurer ended up paying more than $100k for our claim alone, for example. It changed our lives significantly; we were out of our house for about 9 months.

    BTW, the storm system’s rapid movement, described in the article–ca. 9 hours elapsed between striking Atlanta and Jacksonville–is typical of derechos.

  21. 71
    Tokodave says:

    wili @ 5. That’s a good question. There is good evidence of a larger percentage of rain falling as intense precipitation but I haven’t found anything specific for associated increases in wind speed so I’ve relied on proxies; disruptions in the electrical grid and insurance claims. These are imperfect but tell us something….rain makes it wet, wind blows things over and in general its things getting blown over that disrupt the electrical grid. If anyone has a good reference on documented changes in wind speeds I’d be interested in seeing it.

  22. 72
    Hank Roberts says:

    Sorry, Geoff, I’ve been doing this wrong to the extent anyone learns to rely on me as one who points, rather than learning out how to do what I point out can be done. I never point to answers; I point to examples of what can be found by looking. Library reference desks are there to help people do what I point out people can learn how to do. Look beyond the pointer.


  23. 73

    forcing |ˈfôrsi ng |

    force |fôrs|


    1 strength or energy as an attribute of physical action or movement : he was thrown backward by the force of the explosion.

    • Physics an influence tending to change the motion of a body or produce motion or stress in a stationary body. The magnitude of such an influence is often calculated by multiplying the mass of the body by its acceleration.

    Climate Sensitivity
    In Intergovernmental Panel on Climate Change (IPCC) reports, equilibrium climate sensitivity refers to the equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration. More generally, equilibrium climate sensitivity refers to the equilibrium change in surface air temperature following a unit change in radiative forcing (degrees Celsius, per watts per square meter, °C/Wm-2). One method of evaluating the equilibrium climate sensitivity requires very long simulations with Coupled General Circulation Models (Climate model). The effective climate sensitivity is a related measure that circumvents this requirement. It is evaluated from model output for evolving non-equilibrium conditions. It is a measure of the strengths of the feedbacks at a particular time and may vary with forcing history and climate state. See climate, radiative forcing. [1]

    Radiative Forcing
    A measure of the influence of a particular factor (e.g. greenhouse gas (GHG), aerosol, or land use change) on the net change in the Earths energy balance.

  24. 74
    dbostrom says:

    Flakmeister: The PDF link is dead… That is a great and timely quote and it would be nice to have the source….

    2010 — How Warm Was This Summer?


    “Given the association of extreme weather and climate events with rising global temperature, the expectation of new record high temperatures in 2012 also suggests that the frequency and magnitude of extreme events could reach a high level in 2012. Extreme events include not only high temperatures, but also indirect effects of a warming atmosphere including the impact of higher temperature on extreme rainfall and droughts. The greater water vapor content of a warmer atmosphere allows larger rainfall anomalies and provides the fuel for stronger storms driven by latent heat.”

  25. 75
    Geoff Beacon says:


    The easiest way for me to comment on your response to my #32 is to say “all of the above” but I admit I didn’t have evapotranspiration in mind.

    But I’m surprised you didn’t get my drift, which was

    …should we worry that climate models have not got the pace of climate change right and are underestimating these future consequences…

    1. the average world temperatures
    2. the loss of sea ice
    3. melting of glaciers
    4. the increase in droughts
    5. the increase in storms
    6. the increase in wildfires
    7. the loss of biodiversity
    8. the frequency of heat waves
    9. insect infestations
    10. &ETC. & ETC. ????

    [Response:You specifically asked about fires, not all those other things. I’m not sure what you expect these models to do, but the answer appears to be “everything”. I mean it’s fairly unrealistic to expect a climate model to predict fire occurrence and biodiversity loss don’t you think?–Jim]

  26. 76
    wili says:

    Thanks, tim and tok. I lived through the MN event–very weird and scary. I didn’t realize that there were no super derechos before 2009.

  27. 77
    Geoff Beacon says:

    Hank #71

    Thanks for responding but I don’t feel inclined to look for something that isn’t there. I was hoping to make the point that peer reviewed literature on the climate, whilst good, has significant holes.

    It would be helpful if we had more warning signs to warn us of the holes.

  28. 78
    BillS says:

    Re: DP @ #36

    In their book “The Arctic Climate System” Serreze and Barry write (p.293), “It has long been known that variations in the onset and strength of the Asian summer monsoon are in part determined by Eurasian snow cover through impacts on albedo, soil moisture and large-scale ocean-land temperature contrasts…(citations)… . Significant correlations have been found between anomalies of snow cover and the sea level pressure and height fields over the Arctic and North Atlantic…(citations).”

    Here is a paper on this region, it’s a modeling exercise and maybe a bit dated but interesting nonetheless:

    [Response:Projections of changes in the Asian Summer Monsoon (ASM) are actually quite complicated. The South and East ASM are impacted by different climate dynamics, and there are competing mechanisms involving the role of latent & sensible heating, atmospheric stability, and dynamics related to e.g. ENSO. We recently published on this topic: Fan, F., Mann, M.E., Lee., S, Evans, J.L., Future Changes in the South Asian Summer Monsoon: An Analysis of the CMIP3 Multi-Model Projections, J. Climate, 25, 3909-3928, 2012. -Mike]

  29. 79
    Unsettled Scientist says:

    >peer reviewed papera about the missing feedbacks missing feedbacks in climate models?
    >I don’t feel inclined to look for something that isn’t there.

    The question doesn’t make sense. What models? Each model is different. Each model run is different, they are published with their assumptions, and you can read that to see what was and was not included. It simply doesn’t make any sense to say “climate models don’t included X”. Some do, some don’t. There are models for forest fires out there if you look. Not bothering to look doesn’t mean something doesn’t exist.

    I don’t feel inclined to do your work for you, but here is one model of the coupled physics of forest fires and the atmosphere. I think you simply aren’t sure of what question you seek to answer.

    T. L. Clark, M. A. Jenkins, J. Coen, and David Packham. A coupled atmospheric-fire model: Convective Froude number and dynamic fingering. Intl. J. of Wildland Fire, 6:177–190, 1996.

    More fire modeling:

    I don’t really know why I’m doing this, there isn’t a real question I’m trying to answer so I’ll stop.

  30. 80
    Hank Roberts says:

    > I don’t feel inclined to look for something that isn’t there.

    Mhmm. And are you inclined to thank Unsettled, who found some for you?

  31. 81
    Geoff Beacon says:

    Unsettled Scientist @78

    The message I get from the philosopher Wittgenstein is that for a conversation to work both parties have to guess what the other one means. I don’t think you are trying very hard to understand.

    The papers your cite concern individual fires and how they develop. They do not address the important issues I list in #74. They give no clue to world temperature rises or the frequency of droughts throughout the world – although they may be of use to the emergency services. They are weather not climate.

    If I were to say general climate model or Earth systems model instead of just ‘model’ would you understand better? Or did you understand in the first place and were refusing to engage in normal conversation?

    Just to be sure, I’ll answer “What models?” by saying “Those models that are useful in estimating the size of these future consequences…

    1. the average world temperatures
    2. the loss of sea ice
    3. melting of glaciers
    4. the increase in droughts
    5. the increase in storms
    6. the increase in wildfires
    7. the loss of biodiversity
    8. the frequency of heat waves
    9. insect infestations
    10. &ETC. & ETC. ????

  32. 82
    Ray Ladbury says:

    Geoff Beacon,
    I think you are falling into a common trap of laymen when it comes to looking at models–that is, you want a model that will give you “the answer”. That’s now what what scientific models do. Scientific models are there give insight, and scientists, engineers and policy makers (if they are wise) use that insight to anticipate and plan for how bad things might get.

  33. 83
    Patrick says:

    Thank you. Isn’t there moral hazard around “…how bad things might get”–namely, a tendency to conclude that if it’s not too bad then it must be o.k., or, on the other side, a tendency to exaggerate simply to gain attention?

    Isn’t the issue somewhat like the difference between health care and disease-care? How about talking about how good it could get if we went the other way?

    For instance, could somebody please tell me how much healthier I might be likely to be, and feel, if I had a few more ppm of oxygen to breathe? How many marginal ppm are significant–for me, and for human health in general? What’s my optimal oxygen horizon?

  34. 84
    Unsettled Scientist says:


    The quotes you use in your post in your blog are very short. It’s hard to figure out what the context is to even understand what exactly is being said. The second quote doesn’t appear to be a complete sentence even. Wittgenstein likely wouldn’t approve of posting quotes with so little context if mutual understanding is the goal, but if the goal was to make me guess then well done.

    Just to be clear, my “what models” question was asking specifically, which models. Your answer essentially means “all models.”

    If your question is simply what are forest fires in a GCM, Jim’s first reply is probably the best answer: aerosol production, carbon cycling issues or biophysical feedbacks from vegetation such as albedo change or evapotranspiration.

    BTW, are you sure John Mitchell meant Global Climate Model with GCM, or did he really mean General Circulation Model.

  35. 85
    Hank Roberts says:

    > models that are useful in estimating the size of these future consequences

    You’re looking for a review of the literature, one putting models and studies together to sum up what’s known — a consensus statement

    (Scholar’s results will also turn up “advocacy science” PR work, of course.)

  36. 86
    thomas says:

    I have a dumb question but I have wondered about it for a few years. I would not be surprised if you blew me off:
    Mt. Pinutubo, in the early ’90s, exploded with a very large eruption. The resulting particulate matter in atmosphere cooled the planet for a few years. I understand this demonstrated that the best climate models predicted the cooling accurately. Yet I understand large eruptions like this add large amounts of CO2 to the atmosphere( I vaguely remember seeing charts of CO2 levels over the last few decades from Hawaii, that do not show a “blip” related to this but I am not sure). Excuse my ignorance.
    My question is, could this event have contributed to the 1998 el nino and record high temps of that year( I understand those temps have been surpassed since).

    [Response: Pinatubo did release a lot of sulfate aerosols which stayed in the stratosphere for a few years (mostly gone by 1994) and which had a direct cooling effect. The idea that Pinatubo released a climatically important amount of CO2 is however a myth – there is no evidence for this at all. While people have speculated on the impact of big volanoes and El Nino/La Nina responses (there is some evidence for an enhanced likellihood of an El Nino in the year following an eruption and there was one in 1991/1992), the effect (if there is one) is short-lived. 1998 is far enough past 1991 to discount any detectable influence. So, no. – gavin]

  37. 87
    Patrick says:

    [Moderator/webmaster: Please adjust my comment to the following…]

    Isn’t there moral hazard there–namely, a tendency to conclude that if it’s not too bad then it must be o.k., or, on the other hand, a tendency to exaggerate simply to gain attention?

    Isn’t the issue somewhat like the difference between health care and disease-care? How about talking about how good it could get in an optimal scenario?

    And what does the science say about oxygen? What’s the industrial-era oxygen trend, or is the time-frame too short to be meaningful for oxygen?

    I want to know what’s optimal for human health.

  38. 88
    Rick Brown says:

    Geoff Beacon @various: I’m not sure I understand better than anyone else what you’re getting at and even if I have it right it’s not something I have any expertise in. However, you may want to look at the links below. (Fire may or may not be *in* GCMs but that doesn’t mean it can’t be assessed by climate modelers.)

    MC1 dynamic vegetation model, which includes a fire module and can be driven by the output of GCMs at global, regional or landscape scales.

    If you care to look through these articles and the articles that cite them,38 I expect you’ll find references to other climate-coupled vegetation models.

  39. 89
    Ron R. says:

    owl905 — 4 Jul 2012 @ 11:28PM

    Actually, my understanding is that the term “Climate Change” was coined by Republican pollster and marketing whiz, Frank Luntz, in a memo to Reagan and was actually meant as an obfuscatory diversion from the more severe sounding “Global Warming”. So Fox News should embrace it.

    p.142 I think.

  40. 90
    Geoff Beacon says:


    Thanks for replying to my #74

    I don’t expect one model to predict everything but if all models have some missing feedbacks the ensemble of global climate models (GCMs) they will all be lacking and since the feedbacks are overwhelmingly positive. Forest fires are an interesting case because they seem to be missing as forcing agents in all GCMs.

    I’m sorry it come to this but I am criticising most of the community of climate scientists (CCS) for not warning us where the holes in their science are.

    There is a good example of the approach that might be taken to remedy some of these holes. The Special Report on Emissions Scenarios (SRES) had several scenarios of the emissions due to human activity.

    Many model runs have been completed using different scenarios, with different outcomes. Is there a similar approach to climate feedbacks? I don’t see why not.

    If it’s too difficult for a GCM to predict a particular feedback, like forest fires, and we know it might be significant then why not introduce it as a forcing scenario exogenous to the models. (Actually I would favour some measure of endogeny because higher temperatures may mean more fires.)

    You may have misunderstood my question. I wasn’t asking why GCMs don’t (usually?) predict forest fires but why they don’t take them (and other feedbacks) into account.

    Much more importantly. If your argument is “our GCMs can’t be expected to do that”, why don’t you tell us clearly so that our politicians can hear?

    I’m sure you know the Allen/Pierrehumbert line, which I understand as “We can put a trillion tonnes of carbon iin the atmosphere and keep within a 2 degree rise in global temperatures”. Wasn’t this approach reliant on GCMs that did not account for forest fires and many other feedbacks?

    I’m sure you will be aware that their approach puts less emphasis on short term forcing agents (e.g. black carbon and methane). My conversations with government officials (on whom politicians rely) tell me that only now are we getting a reluctant recognition that we need the time that a reduction of short term forcing agents will bring to begin to address the horrors of climate change.

    If the CCS warned us their GCMs were underestimating future problems we might also start to put some effort into geoengineering research and argue for an enormous carbon price.

    If you have been telling us, I didn’t hear. Is it time to take Rupert Murdoch’s advice and hire some real pros to get the message across. I could make some suggestions.

  41. 91
    Geoff Beacon says:

    Ray Ladbury #81

    Scientific models are there give insight, and scientists, engineers and policy makers (if they are wise) use that insight to anticipate and plan for how bad things might get.

    Without the missing feedbacks they can’t tell us how bad things might get.

  42. 92
    Terry says:

    Ray @81

    But one should never lose sight of the famous adage attributed to Dr Box.

  43. 93
    Geoff Beacon says:

    Unsettled scientist #81

    See the comments at the end of Climate officials and climate provisionals

    Note John Mitchell’s comment

    I would add that although these things may be important, they are not always easy to quantify, model, initialize and validate, especially 5-7. That is why is taking time ot implement them.

    Sometimes it is hard to get straight answers from climate scientists. John Mitchell has always answered my questions directly.

  44. 94
    Geoff Beacon says:

    Unsettled Scientist #81

    Global Climate Models or General Circulation Models? You are probably right. I also have Earth Systems Models ringing in my head. But do any of them have a decent set of feedbacks in them?

    I seem to read about new ones every day. e.g. Global warming turns tundra to forest-study. Even though watching climate science much more closely than anyone I know – but I may be bested by some RealClimate afficionados – I can’t remember them all.

    As an informed representative of the public who regularly doorsteps policymakers I would like some guidance that I can trust.

  45. 95
    Geoff Beacon says:

    Hank Roberts #84

    OK, I go to my MP and say “Climate change is very dangerous go an put ‘consensus statement’ into Google Scholar and you will find how bad it is”


    And when I followed your link the first paper cited was How to Manufacture a Climate Consensus by Patrick J Micheals (Cato Institute).

  46. 96
    Killian says:

    These perspective generally seem to reflect the high rte of change we’ve been seeing in the weather, land changes and sea ice since 2005.


  47. 97
    flxible says:

    Patrick@86: “I want to know what’s optimal for human health”
    Optimal health is dying at the slowest possible rate ;)

  48. 98
    Ray Ladbury says:

    I think you are missing the point–the models allow you to explore different feedback scenarios. None of these scenarios may be “real”. However, they will provide insight. This insight can be added to insights gleaned from other models. The point is that this is more of an engineering and planning issue than it is a scientific issue–and these fields too have their models. It is these models that try to “bound” how bad it can get (e.g. SLR, length of drought, flood magnitude…), based on input from scientists.

  49. 99
    Hank Roberts says:

    Geoff: what you got is just as I told ya!
    “(Scholar’s results will also turn up “advocacy science” PR work, of course.)”

    There is no substitute for actually searching, thinking, and making choices; when you take what others give you, you get fed what they knew and want you to have, and at best it is outdated by the time you read it.

  50. 100
    flxible says:

    I think the point that Geoff is missing is that climate modeling is a tool to aid the understanding of how the global system works, not to predict future weather in detail. Climatologists have shown us the changes taking place are largely a result of perturbations of the system caused by humanity. The answers to the questions of the specific size of the listed consequences are a matter for risk analysis best addressed to ecologists, social planners and … insurance companies.