Testing the IRIS Hypothesis

I thought I might revert back to a bit of physics and discuss a recent paper that aims to try and test the Iris hypothesis. The Iris hypothesis originates with Lindzen &Chou (2001) and proposes that as we warmed, there would be a reduction in cloud cover in the tropics, which would allow for more infrared radiation to escape to space and would – consequently – act as a strong negative feedback.

credit : Mautitsen & Stevens (2015) Figure 2

credit : Mautitsen & Stevens (2015) Figure 2

The recent paper that tests this is Missing iris effect as a possible cause of muted hydrological change and high climate sensitivity in models by Thorsten Mauritsen & Bjorn Stevens. There are, I think, two motivations for this recent paper. One is that recent observations suggest that climate models might be over-estimating climate sensitivity and (which I had not realised) under-estimating changes to the hydrological cycle. There is also one model-data mismatch that may be consistent with an Iris effect. The figure on the right shows the short- (horizontal axis) and long-wavelength (vertical axis) sensitivity in the tropics. Climate models produce the same kind of short-wavelength sensitivity to that observed, but tend to underestimate the long-wavelength sensitivity. This suggests that the increase in outgoing long-wavelength flux with temperature is greater than climate models suggest, and is at least consistent with an Iris-like effect.

Since the Iris effect is essentially a reduction in cloud cover, and an increase in the size of the infrared window, in the tropics, this was implemented in the models by simply introducing a term, I_e, that allowed them to adjust the rate, C_p(T_s), at which cloud water was converted to rain. Essentially

C_p(T_s) = C_o (1 + I_e)^{T_s - T_o},

where C_o is the default rate, T_s is the surface temperature, and T_o is a typical temperature in the tropics.

The basic result is shown in the figure below. The grey dots in the left-hand panel show the equilibrium climate sensitivities (ECS) for a range of different climate models. The red dot is for the ECHAM6 model, which has an ECS of 2.8K. The yellow, light-green, and dark-green symbols show the impact of the Iris effect for I_e = 0.2, 0.5 and 1.0, but considering the long-wavelength effect only. This brings the ECS down into the range suggested by Lindzen & Chou (2001). The blue symbols, however, show the ECS when the short-wavelength and other feebacks are also included. The net effect is relatively small, with the ECS reduced from 2.8K, to between 2.2 and 2.5K, depending on the value of I_e. The right hand-panel illustrates why. The long-wavelength effect is quite large, changing the feedback from around +0.5Wm-2K-1, to between -0.4 to -0.8Wm-2K-1. However, there are also changes to the water vapour feedback, lapse rate feedback, and short-wavelength cloud feedback that results in a relatively small net change in overall feedback.

credit : Mauritsen & Stevens (2015) Figure 3

credit : Mauritsen & Stevens (2015) Figure 3

So, this seems like an interesting paper that is really just testing what would be the consequences of there being an Iris effect, without actually demonstrating that it does exist. There are, however, some interesting hints. The results suggest that the Iris effect would reduce the ECS to bring the models more in line with what recent observations suggest. The change is, however, not big enough to bring it down to the kind of values suggested by Lindzen & Chou and, for the model considered here (ECHAM6), the change is from 2.8K to 2.2K at most. The Iris effect would also increase the hydological sensitivity which, again would make models more consistent with observation. Additionally, models currently underestimate the long-wavelength sensitivity in the tropics which is, again, consistent with a possible Iris effect.

Ultimately what this seems to be showing is that if observations do suggest that models are over-estimating climate sensitivity and under-estimating hydrological sensitivity, this could due to an Iris effect that is not being properly represented in the models. It’s almost certainly too early to know if models really are missing something like an Iris effect and consequently over-estimating climate sensitivity, but it’s an interesting paper that certainly presents some intriguing hints.

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90 Responses to Testing the IRIS Hypothesis

  1. dana1981 says:

    It’s worth explicitly noting that there are a number of reasons to think the recent energy balance model estimates of lower ECS (Otto, Lewis, etc.) are flawed (various reasons including assuming constant feedbacks and using highly uncertain forcing estimates), in which case one of the pieces of evidence in favor of the Iris hypothesis cited in this paper could actually be considered evidence against it (i.e. it results in a too-low ECS value). But it is interesting that even the lower ECS values cited in this study are still far higher than the values claimed by Lindzen of <1°C for 2xCO2.

  2. Meow says:

    From the abstract:

    A controversial hypothesis suggests that the dry and clear regions of the tropical atmosphere expand in a warming climate and thereby allow more infrared radiation to escape to space.

    From your discussion:

    Climate models produce the same kind of short-wavelength sensitivity to that observed, but tend to underestimate the long-wavelength sensitivity. This suggests that the increase in outgoing long-wavelength flux with temperature is greater than climate models suggest, and is at least consistent with an Iris-like effect.

    Would not an iris effect of the kind described also increase absorbed solar radiation in the tropics, thus increasing climate sensitivity? How do the authors address this issue? Do they hypothesize that the effect operates only at night?

  3. Dana,
    Indeed. I had thought of going into that, but the post was getting a bit long. I’ll link to this where I discussed various reasons to be cautious about EBM results. Also, this paper really only suggests a largish effect if you assume quite a substantial Iris effect ($latex I_e = 1.0), and even a largish effect is to reduce the ECS from 2.8K to 2.2K. For a weaker Iris effect, the effect could be quite modest.

  4. Meow,

    Would not an iris effect of the kind described also increase absorbed solar radiation in the tropics, thus increasing climate sensitivity?

    Yes, I think that’s the SW feedback. So, when you reduce the cloud cover, you increase the outgoing long-wavelength flux, but the SW feedback becomes more positive, and this (I think) is what you’re referring to. That’s why the net effect is quite small and why it’s not possible for the Iris effect to reduce the ECS down to levels suggested by Lindzen & Chou (2001).

  5. Magma says:

    There’s a simple short cut based on psychology to quickly (though non-rigorously) evaluate the status of the Iris hypothesis.

    Since proposing it in 2001, Lindzen has pretty much left quietly abandoned her to a sad and lonely fate off the back roads of research. “Daddy,” Iris softly calls out, again and again, “when are you coming back? I’m so hungry.”

  6. Richard says:

    ATTP, you say it “was implemented in the model by simply introducing a term …” But surely (assuming there was at least some attempt to model the hydrology over different lands and sea, the Iris effect if real would be manifest as an emergent property, not a ‘bolt on’. Am I being naive, stupid or both?

  7. Richard,
    I think that is a fair point, but I think the issue is that the Iris effect – if it exists – is probably due to convection which climate models can’t represent self-consistently because the scale is too small. So, convection is typically parametrised and it could, therefore, be that the manner in which it is parametrised means that it isn’t capturing all the possible effects.

  8. One is that recent observations suggest that climate models might be over-estimating climate sensitivity and (which I had not realised) under-estimating changes to the hydrological cycle.

    A good explanation for the too strong trend in precipitation would be non-climatic changes.

    An important measurement error for precipitation is that due to the turbulent flow around the rain gauge, the drops do not land in the gauge, but hop over them. This is called undercatchment. For rain this is typically an error of 10%, for snow it can be even 50%. Ball park numbers.

    In the early instrumental period (about before 1900) it was common to install rain gauges on roofs. Probably people thought that that would nicely reduce obstructions (trees, buildings) from reducing the rain amounts. However roofs are also more windy, the gauges thus had more undercatchment.

    Nowadays, wind screens are often installed around rain gauges, especially in snowy countries where the problem is most severe. Both improvements lead to reductions in undercatchment and to non-climatic increases in observed precipitation. Unfortunately, I do not dare to estimate how much this would be on a global average. We hope to be working on this in our Parallel Observations Science Team.

    I am not fully sure, but as far as I know, current global collections of precipitation observations are not homogenized. Thus it seems likely that the non-climatic change is still in the data.

    (The observed change in strong precipitation are even larger and also larger than the models predict. Unfortunately, the models are not that good in severe precipitation.)

  9. Richard says:

    Oh, I see (I think). Actually, that raises another question that maybe you can help me with. What cell sizes are being used now with latest computing power, and is the cell size fixed or variable (eg might one use smaller cell sizes near surface of earth for reasons you mention, and other boundary effects? Or indeed, is there a natural limit to useful reduction in cell size for climate models, as in law of diminishing returns (as opposed to weather models) (averaged global and regional trends over decades versus local simulations over hours)? Or is size always important (small in this case!)

  10. Bill Illis says:

    Obviously, Figure 3 shown above is off by mile on the feedbacks.

    It should show ECHAM6 as +1.7 W/m2/K rather than -1.1 W/m2/K.

    If the two most important feedbacks were truly -1.1 W/m2/K, warming from CO2 doubling would only be 0.74C per doubling.

    (I built a calculation model for these feedbacks).

  11. MIchael Hauber says:

    Dana,

    the paper does not cite energy balance model estimates of ECS as far as I can tell, but seems to be referring to the fact that the observed increase in temperature is slightly slower than the model mean. It does cite several papers that also attempt to explain this discrepancy, such as Shindell (aerosol), Santer (volcano) and Trenberth (deep ocean). A quick look at these papers shows that Shindell is actually referring to a lower transient climate sensitivity, Santer is referring to a lower rate of temperature increase and Trenberth is the missing heat issue which I thought was an energy accounting issue and not a model vs observation issue. The discrepenacy between model and observation that this paper then seeks to explain does seem to be unclear (unless I’ve missed something).

    And of course the flaws in energy balance models would only be evidence against this paper if there was a reasonable case to be made that they would push ECS up to or above that estimated by the circulation models. Is there such evidence? How do we know that the flaws in energy balance models won’t push the ECS even lower?

  12. MIchael Hauber says:

    MEOW, ATTP,
    I don’t think the ability of clouds to both absorb infrared from below (causing warming) and reflecting solar radiation from above (cooling) are the issue, and I can’t imagine Lindzen making such a basic mistake as to include only the warming effect and not the cooling. This paper does find a much weaker IRIS effect then Lindzen, and much of this is associated with short wave effects, but not because Lindzen failed to include these effects, but rather due to Lindzen not including enough of the types of clouds that have a high short wave effect. In particular Lindzen considers only a reduction in cirrus clouds only where deep convection occurs, whereas this paper finds that these clouds reduce ‘virtually everywhere’

    p.s. in further reading of the paper to make this comment I found the reference to energy balance models which I could not find and referred to in my previous comment….

  13. Roger Jones says:

    Victor, there are a couple of gauge-corrected data sets around. One was put together by Willmot, Legates and others. I built one for western Victoria for work that I was doing twenty years ago and am sure that the increase in heavy rainfall data is real. Have been out of this stuff for a while, but there seems to be renewed interest in it.

  14. Lindzen is the guy that apparently had the first behavioral model for QBO.
    Holton, James R., and Richard S. Lindzen. “An updated theory for the quasi-biennial cycle of the tropical stratosphere.” Journal of the Atmospheric Sciences 29.6 (1972): 1076-1080.

    We are using the QBO measurements directly as a forcing function to a wave equation model of ENSO :
    http://forum.azimuthproject.org/discussion/1608/enso-revisit

    My impression of Lindzen is that he creates these “just-so” stories of how the climate should behave. With his patient stentorian tone, he gives people the impression that he knows what he is talking about.

    I don;t know — his Iris Theory seems to have been debunked. I would suggest moving forward and make progress where you can find reduced complexity in the climate system.

  15. Bill Illis,
    I don’t understand your comment as Figure 3 does show ECHAM6 having a net feedback of around +1.7Wm-2.

    Michael,
    Thanks. I haven’t looked closely at Lindzen & Chou (2001) for a while.

  16. Frank says:

    The “what/if” approach of the paper is very interesting and the result reduces the obs.-model differeneces on 3 fields: 1. The slightly overestimation of ECS; 2. The overestimation of the tropical hotspot ( see fig. S7); 3. The muted water cycle in the models. If the used physical hypothesis would be wrong than the outcome would make me wonder.

  17. Richard,
    I’m not sure, but this link (which was updated in 2013) suggests a horizontal resolution of 250km – 600km, 10 – 20 layers in the atmosphere, and maybe 30 in the oceans.

    Frank,
    It is interesting in that respect, but I think we can’t rule that the model/obs discrepancies are also – or partly – simply a consequence of internal variability.

  18. Olof says:

    A possible “iris effect” with less AGW but expansion of dry and clear areas…
    Larger desert zones on Earth, is that really good news? What’s the opinion of Californians, North Africans, etc.?

  19. Roger Jones, yes, you are right there are several national or regional precipitation datasets that have been statistically homogenized. The dataset of Canada is also very carefully homogenized using a lot of metadata about the different rain gauges used and how much undercatchment these have.

    The expectation that mean precipitation increases by about 2% / °C is, however, for the global mean. Locally it may well vary a lot depending on other changes. I do not know of homogenized precipitation datasets. The Global Precipitation Climate Centre is working on one, but I think they are not finished.

    Did you also check whether, when your data would have had a bias, how much of that bias you can remove with statistical homogenization? Precipitation is very hard to homogenize, being highly variable. I would be interested in such a number.

  20. Richard S.J. Tol says:

    Has someone mentioned yet that Dick Lindzen is on the advisory board of the Global Warming Policy Foundation and that the iris effect therefore cannot be true?

  21. Richard,
    You have now. Noone else had, until you did, though.

    I notice that you seemed a bit put out by Joshua’s response to your comment on Climate Etc. I must admit, that I had taken your comment more in the sense that Mosher took it and broadly agreed with what you were saying. To be fair to Joshua, though, he may just have been taken aback by you appearing to say something pleasant?

  22. Paul S says:

    Something I suggested a while ago was for someone to follow through on Lindzen’s ideas and produce an impact study based on typical emissions scenarios. A typical assumption in general discussion about climate change is that damages will scale with temperature increase, and therefore higher sensitivity is worse than lower sensitivity. If lower sensitivity occurs as a result of huge changes in the hydrological cycle, is that really true?

  23. Paul S,
    I think that’s a good point and is probably related to what Olof was suggesting. Presumably a consequence of a strong Iris effect would be an expansion of the dry areas and a corresponding increase in intense precipitation events in the regions just outside this dry area?

  24. BBD says:

    I’m curious as to how the hypothesised IRIS effect can be reconciled with an event like the PETM. Presumably Paleocene boundary conditions (hotter / much higher SSTs than Holocene, especially equatorial) would have engaged the IRIS negative feedback quite strongly, increasing the amount of forcing required to drive the climate out of quasi-equilibrium and into a hyperthermal. Then the GHG-forced temperature excursion itself would have been inhibited by the increasing IRIS negative feedback. This suggests that the forcing change (GHG pulse) required to drive the hyperthermal event would have to have been much larger than currently estimated.

  25. BBD,
    Would be interesting to get James Annan’s take on this. The paper here suggests an ECS maybe as low as 2.2K, but could be 2.5K (and that’s from a single model with a non-Iris ECS of 2.8K). I think James Annan’s work has suggested an ECS around 2.5K, so he may have considered whether or not that could be consistent with the PETM. Although, I guess your point is a bit more than that because you’re suggesting that the Iris effect should become stronger in a warmer world?

  26. Frank says:

    ATTP: “Frank, It is interesting in that respect, but I think we can’t rule that the model/obs discrepancies are also – or partly – simply a consequence of internal variability.”

    What do you think about the pobability that a (randomly) variability works in the “right” direction in 3 (undependend?) fields??

  27. Frank,
    3 probably isn’t all that unlikely 🙂 To be clear, I wasn’t suggesting that it is simply some kind of internal variability, simply that this one paper isn’t the end of the story. There are other explanations for the model/obs discrepancy with respect to ECS. As Victor points out, there isn’t a full, homogenized precipitation dataset. The interesting one may be the long-wavelength sensitivity as I’m unaware of any alternative other than models are underestimating how dry it is getting in the tropics.

  28. BBD says:

    ATTP

    Although, I guess your point is a bit more than that because you’re suggesting that the Iris effect should become stronger in a warmer world?

    I would have thought that it must, but I’m really just wondering out loud. I know JA and JH were looking at the LGM / Holocene transition to get the ~2.5C ECS estimate, but I would indeed be interested to hear either of their views on how IRIS fits – or doesn’t fit – with the PETM.

    As I said, the other potential problem is that the lower S goes, the more carbon is required to force the PETM hyperthermal and I think this throws up problems with finding a big enough source (or combination of sources) and the upper limits suggested by the size of the carbon isotope excursion (CIE) in cores etc.

  29. Joshua says:

    ==> “Has someone mentioned yet that Dick Lindzen is on the advisory board of the Global Warming Policy Foundation and that the iris effect therefore cannot be true?”

    I see once again, that Richard Tol is focused, laser-like, on the science and will steadfastly refuse to let personality politics distract his focus.

    Which, of course, is why he added that comment on personality politics to a thread which had, theretofore, contained comments that were focused exclusively on the science.

  30. Joshua says:

    Anders –

    I’ll understand completely if you want to delete the 1:37. It isn’t lost on my that it was, also, talking about personality politics (so the irony was only 1/2 unintentional). 🙂

  31. JCH says:

    What is the current trend in warming of the surface of the earth? Using GISS for 2014, the trend was .13C per year. The last 9 months is .27C, and the on going El Nino could run that up to an even higher number. Wonder what the highest 9-month trend was in 1998?

    Thank goodness that IRIS is doing an amazing job of reducing warming.

  32. Willard says:

    > he may just have been taken aback by you appearing to say something pleasant?

    Another hypothesis is that Richard praised what honest brokers may criticize as stealth advocacy.

  33. Willard says:

    Oh, and JCH won another thread at Judy’s:

    Bjorn Stevens is a man of courage. Got nuggets made of brass. Walks into burning buildings and saves women and children. Beats up neighborhood bullies. Dives into black water and saves drowning teenagers. Helps little-old ladies across the street.

    If he’s a member of the APS, there’s a special thread on Climate Etc. made just for him.

    http://judithcurry.com/2015/04/22/bjorn-stevens-in-the-cross-fire/#comment-696525

  34. Willard says:

    Oh, and speaking of neighborhood bullies:

    A new study commissioned by CNN’s “Anderson Cooper 360°” found that the stereotype of the schoolyard bully preying on the weak doesn’t reflect reality in schools.

    Instead, the research shows that many students are involved in “social combat” — a constant verbal, physical and cyber fight to the top of the school social hierarchy.

    “Kids are caught up in patterns of cruelty and aggression that have to do with jockeying for status,” explains Robert Faris, a sociologist whom “Anderson Cooper 360°” partnered with for the pilot study. “It’s really not the kids that are psychologically troubled, who are on the margins or the fringes of the school’s social life. It’s the kids right in the middle, at the heart of things … often, typically highly, well-liked popular kids who are engaging in these behaviors.”

    http://www.cnn.com/2011/10/10/us/ac-360-bullying-study/

    I think it is fair to say that scientists are no exception.

    This also seems to apply to econometricians.

  35. JCH says:

    Well, maybe he’s not a member.

  36. dhogaza says:

    ATTP:

    “Richard,
    I’m not sure, but this link (which was updated in 2013) suggests a horizontal resolution of 250km – 600km, 10 – 20 layers in the atmosphere, and maybe 30 in the oceans.”

    For the runs used for AR5, GISS Model E used grids of 2 (about 220 km) degrees latitude by 2.5 degrees longitude (about 275 km at the equator and about 220 km at mid-latitudes), forty layers deep.

    They can couple this with one of two ocean models per run.

    Groups with less formidable computing power available to them would have to use larger grids, of course. All things being equal, halving the linear resolution while maintaining the same layers requires 8x the computing power, I believe – 4x to account for there being 4x as many “pizza boxes”, and another doubling to cut the time step in half to be able to continue to properly propagate results to neighboring cells.

  37. John Hartz says:

    Hot off the press and directly related to the OP…

    A new paper currently in press shines light on climate feedbacks and the balance of energy flows to and from the Earth. The paper was published by Kevin Trenberth, Yongxin Zhang, John Fasullo, and Shoichi Taguchi. In this study, the authors ask and answer a number of challenging questions. Their findings move us a big step forward in understanding what is happening to the planet now, and how the climate will evolve into the future.

    So, what did the scientists do? First, they used measurements at the top of the Earth atmosphere to count the energy coming into the Earth system and the energy leaving the planet. The measurements were made by satellites as part of the Clouds and Earth’s Radiant Energy System project (CERES for short). By subtracting one energy flow from the other, they found what is called the Earth’s energy imbalance. Most studies show that the energy imbalance is in the range of 0.5 to 1 Watt per square meter of surface area, which is causing ongoing global warming.,

    Changes in water vapor and clouds are amplifying global warming. by John Abraham, Climate Consensus – the 97%, The Guardian, Apr 23, 2015

  38. John Hartz says:

    Also from the Abraham article cited above…

    What the present paper shows is that future changes to clouds will cause slightly more warming. Scientists describe clouds as a “positive feedback” on global warming. This finding is consistent with the work of Dr. Andrew Dessler. He had published work here and here showing changes in clouds are making the Earth warm more than otherwise expected.

    The results of this study harken back to prior work by one well-known skeptic Richard Lindzen who published work on climate feedbacks in 2009, and by another well-known skeptic Roy Spencer who wrote an article in 2011. Those works, among others, reportedly show that the Earth is less sensitive to increases in greenhouse gases. This new work confirms the opposite; it turns out Dr. Dessler was correct after all.

  39. BBD says:

    Thanks for the links John H. Interesting.

  40. MIchael Hauber says:

    BBD,

    I see two possibilities on IRIS vs PETM. Either one of them is wrong. Or the two can be reconciled by an additional positive feedback. Note that any estimate of climate sensitivity from PETM is going to be an earth system sensitivity including additional carbon cycle (and other forcings – GHGs and aerosol) feedbacks beyond what is considered in an ECS sensitivity. Combining lower estimates of ECS from observational methods with the paleoclimate record suggests thepossibility that ECS may be in the lower half of what is commonly estimated, while long term and earth system feedbacks may be higher. So the following century may see slower warming, but the warming could be worse than expected over following centuries and millennia as the earth system feedbacks kick in.

    Also according to Zeebe et al the issue with PETM isn’t finding enough carbon, it is that the isotope record constrains how big a relative carbon increase could have occurred. Evidently the amount of carbon in the atmosphere at PETM is poorly constrained, but we have evidence that the increase was less than 70% of pre-event levels.

    http://www.nature.com/ngeo/journal/v2/n8/full/ngeo578.html

  41. MIchael Hauber says:

    On Trenberth et al, the feedback they find ‘would then imply a climate sensitivity of 1.62 K’. However this is only short term effects, and measured in the troposphere, and so should not be compared to equilibrium climate sensitivity measurements. Despite contrary claims in the Guardian at Skeptical science they do not seem to have proved that cloud feedbacks are positive – they state that ‘the regression coefficient between global RT and tropospheric temperature becomes -2.98 if water vapor effects are removed, slightly less than the expected black body radiation (3.2) suggesting a positive feedback from clouds and other processes’. As 2.98 is close to 3.2 I’m guessing the feedback is not particularly strong (3.2/2.98?) and that a positive feedback for clouds and other processes could mean positive for other processes and negative for clouds. Perhaps ‘other processes’ can reasonably be expected to be small enough that clouds must be positive?

    A further point is that not only does Thorsten and Stevens hint at drying in the subtropics, it also suggests that a mechanism for the IRIS effect may be increased aggregation of tropical convection. A stronger tendency for tropical thunderstorms to cluster together would seem to suggest more favourable conditions for large hurricanes.

    The point that a reduced climate sensitivity due to effects such as IRIS may be bad new and not good news is one I certainly think needs to be reinforced.

  42. BBD says:

    Michael Hauber

    I see two possibilities on IRIS vs PETM. Either one of them is wrong. Or the two can be reconciled by an additional positive feedback.

    It is certainly possible that the PETM was forced by an initial release of GHG and then further carbon cycle feedbacks (eg. volcanism -> clathrate destabilisation). This, however, would not really reconcile a strong IRIS negative feedback with a major hyperthermal like the PETM for reasons I touched on in previous comments.

    I should have been clear that I wasn’t trying to extract a Charney sensitivity from the PETM 😉

    That said, the ESS is *lower* in hot climate states as the cryosphere is absent or diminished and the slow ice albedo feedback is absent or diminished. So when considering the PETM, it is reasonable to propose that the ESS and the fast-feedbacks ECS are much closer together than they are during the Pleistocene.

    Zeebe et al. (2009) is not the last word. A review paper by Dunkley-Jones et al. (2010) points out that Z09 may have over-estimated the upper bound of PETM temperature increase and under-estimated the size of the carbon release. If so, there would be no need to invoke unknown feedbacks to explain the PETM, nor would it imply sensitivity above the current generally accepted range.

  43. BBD says:

    For the thread – Andrew Dessler has just posted an article at RealClimate:

    It’s also worth pointing out what this study [Mauritsen & Stevens] doesn’t prove. It doesn’t validate Lindzen et al.’s original hypothesis — in fact, it does the opposite – even with an iris effect, the sensitivity does not become negligible. Additionally, there is little evidence that the rate of conversion of cloud water to rain actually changes with temperature, although Mauritsen and Stevens show that incorporating the iris into the model does improve the model’s simulations of some aspects of the climate system (even though it doesn’t change climate sensitivity much).

    I view this as a what-if calculation of the impact of such a process. Future research may validate this, or it may not. This kind of calculation is one of the reasons why we like using models, of course.

    Another argument against the iris comes from my work looking at the cloud feedback in response to short-term climate variability. If the iris provided a strong negative feedback, then we would expect to see it in response to short-term climate fluctuations. Analysis of observations doesn’t show anything like that (Dessler, 2013).

  44. BBD says:

    Sorry VTG – crossed there.

  45. Brandon Gates says:

    Completely off-topic: will someone, anyone, please say something –anything — logically rational to me. 2 plus 2 is roughly equal to 4 would suffice. I’m this close > < to calling Scotty for a beam-up. Thanks in advance for your assistance in this matter.

  46. BBD says:

    Brandon G

    Is it something I said? Or someone else? If I’m not making sense, I’ll be happy to try again 😉

  47. Brandon asks:


    Completely off-topic: will someone, anyone, please say something –anything — logically rational to me. 2 plus 2 is roughly equal to 4 would suffice.

    How about this one? She wants to become an astronomer and “slay the fraud of AGW”.
    http://en.gravatar.com/linneamogren

    The stuff one finds at Tallbloke’s Talkshop is mind-blowing freakin psychedelia.

  48. Brandon Gates says:

    BBD,

    Yes, YES … it’s your very existence you cursed moron!!! You don’t even need to POST and I can feel your idiocy. AAARGH!!!

    Kidding. Bane of my existence today, and yesterday, and the day before, is one Richard S. Courtney of somewhere in the British Isles that I think would make a rather picturesque scene as the site of a nicely smoking crater. All got started when I fired a shot across Patrick Frank’s bow … do you know the backstory on this guy? It’s a fascinating exercise in mathturbation followed by thoroughly pig ignorant logic fail. So anyway, he’s still thumping his “teh modulz can’t resolve CO2 forcing because they’re off +/-4 W/m^2 on DWLR cloud forcing, and that error propagates to …” well here, I’ll just quote him directly:

    The uncertainty is so large because ±4 W m-2 of annual long wave cloud forcing error is ±114´ larger than the annual average 0.035 Wm-2 forcing increase of GHG emissions since 1979. Typical error bars for CMIP5 climate model projections are about ±14 C after 100 years and ±18 C after 150 years.

    Dr. Frank bowed out when I observed that if we start the error propagation at 1850 by 2000 we’d expect … ±18 C of error, right? “What’s the actual error as of 2000?” I asked, oh so innocently. TWICE I asked. [crickets]

    So Courtney took over giving me the runaround — he was already in the mix anyway — and as you’d expect it turned into one of those, “show me your evidence, nope that’s not evidence, show me your evidence, nope that’s not evidence, what’s your definition of, nope you didn’t provide a definition …… Gates you’re a lying troll please stop filling up threads with your daft nonsense” tail-chasing exercises the idjuts run when they’re caught between a steep cliff and a boulder which happens to be moving toward said precipice.

    So, I’m pinging for signs of intelligent life. Speaking of …

    WebHubTelescope,

    How about this one? She wants to become an astronomer and “slay the fraud of AGW”.

    Say, she’s not bad looking … ‘allo love, what did you say you were studying again?

    The stuff one finds at Tallbloke’s Talkshop is mind-blowing freakin psychedelia.

    Salvadore de Prete takes the cake wherever I see him surface. But the Ian guy, what’s he called ah, Wilson: https://tallbloke.wordpress.com/tag/ian-wilson/

    Shades of what Vaughan Pratt is working on, but I can’t tell if Wilson is only mildly crankish instead of full-on bonkers, whilst Pratt seems totally on the level.

  49. Bane of my existence today, and yesterday, and the day before, is one Richard S. Courtney of somewhere in the British Isles that I think would make a rather picturesque scene as the site of a nicely smoking crater.

    Actually, if there was one single person who got me started on this whole blogging lark, it was Richard S Courtney – after a brief foray onto WTFUWT. That may still make him the bane of your existence, of course 🙂

  50. Brandon Gates says:

    Anders,

    Oh I do have a choice in the matter, but I’m stubborn. It makes things so much better that his chicanery prompted you to create this forum. You and your crew both educate me and give me a good place to vent my spleen. Both are surely appreciated. Cheers.

  51. BBD says:

    Brandon G

    Sorry, I’ve been inattentive. But as we know, any interaction with R. S. Courtney of the dominionist theological persuasion will run in to the rock of faith. If God Sez I’m Right and you aren’t, that’s all she wrote.

  52. Eli Rabett says:

    Interestingly enough another of the precocious had her Andy Warhol back in 2008. Richard Tol thought the world of her. A tell if there ever was one.

  53. Blast, now you’ve gone and mentioned the Tol. Now his “I’ve been mentioned on a blog alarm” will go off and he’ll come over and make what he thinks is some kind of insightful and illuminating comment, which would normally invoke a “WTF?” response from anyone remotely sensible.

  54. Actually, I’ve just gone and read Richard’s comment on Deltoid. WTF?

  55. Brandon,


    Salvadore de Prete takes the cake wherever I see him surface. But the Ian guy, what’s he called ah, Wilson: https://tallbloke.wordpress.com/tag/ian-wilson/

    I have to disagree — the one that takes the cake and leaves it in the rain is this dude Paul Vaughan. Science played out as a theater of paranoia.

  56. Brandon Gates says:

    BBD,

    Sorry, I’ve been inattentive.

    No worries, in the meantime another risible bit of nonsense from one Pat Frank, PhD (chemistry) (allegedly) gurgled and clawed its way out of the muck. A sampling:

    Brandon, you wrote, “I repeat: Please describe for the class what the actual error is as of the year 2000.”

    Your question is meaningless, Brandon. Propagation of error yields an uncertainty, not a physical error. I’m presuming physical error is what you mean by “error.” Back to the back of the class.

    Here’s the real meaning of the (+/-)18 C uncertainty obtained when (+/-)4 W/m^2 average cloud forcing error is propagated from 1850: the GCM-projected year 2000 air temperature has no physical meaning.

    That’s because the GCM-inherent theory-bias error means the underlying physical behavior is wrongly expressed within the model even if the projected air temperature itself is close to the observed temperature. And the reason for that last, Brandon, is that tuned models merely hide their internal error. They do not produce physically unique solutions, and so cannot produce predictions in any scientific sense of that word.

    Emphasis in original. Literally, he’s been on this schtick since at least 2008. Gavin Schmidt laid the smackdown on him for this SAME nonsense, but the man is undeterred even after getting shellacked on RC in the comment thread by a leading expert in the field. The fun starts hereish: http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/comment-page-8/#comment-88056

    UNbelievable. I mean seriously. A propagated +/- error, or uncertainty if we MUST INSIST, either means:

    1) The modelled prediction is expected to vary between both extremes, or
    2) Over time the modelled prediction is expected to trend toward one extreme or another.

    (1) is “random” error, (2) is bias, yes, but how can a bias be +/-?? I don’t see any other way to interpret it except as (1). Which is silly.

    So, stones to the fire, like clockwork he predictably fell back to, “durrrr, tuned models merely hide their internal error.” bwahahahaha! Um. Isn’t the purpose of tuning models to correct error? How many other tuned parameters did he include in his propagated error … I mean uncertainty … calculation?

    Doing: goose eggs so far as I can tell. Where do these people come from??

    But as we know, any interaction with R. S. Courtney of the dominionist theological persuasion will run in to the rock of faith.

    No kidding, how did I miss that.

    If God Sez I’m Right and you aren’t, that’s all she wrote.

    Things make so much more sense now.

  57. Brandon Gates says:

    WebHubTelescope,

    Harumph, well it’s disconcerting that my read of Vaughan didn’t pick up on that. Looks like I need to re-read some old threads. Don’t you two have some common ground on LOD as a plausible internal variability driver?

  58. Brandon, There is Vaughan Pratt and there is Paul Vaughan. Both are looking at LOD, but one is crazy and one is not. Hint: the Stanford professor is not crazy.

  59. Brandon Gates says:

    Web,

    I was indeed thinking of Paul Vaughan of Stanford but wrote Vaughan Pratt instead. I have no clue who Pratt is, other than I’ve obviously read his name somewhere. Anyway, good to hear that I’m not crazy for thinking that Stanford Vaughan isn’t crazy … I’m pretty keen on seeing him get an LOD paper published, it looks promising to me on the basis of the fits I get with it in my own regression model.

  60. JCH says:

    Vaughan Pratt is at Stanford. I think you have your Vaughans switched.

  61. Yes, this is Vaughan Pratt. Paul Vaughan I don’t think I’ve encountered.

  62. Brandon Gates says:

    JCH, yes I’ve got them switched, NOW, it’s Webby’s fault!

    Anders, That’s the guy I was thinking of, right down to his face. Vaughan Pratt of Stanford. Not crazy. Though I may be going round the bend. 🙂

  63. JCH says:

    You guys still have this mixed up. Vaughan Pratt is straight-up bonkers. Has to be. Only crazy people are that much fun.

  64. Brandon Gates says:

    JCH,

    Only crazy people are that much fun.

    Why thanks, I strongly believe that we are.

  65. Brandon Gates says:

    ATTP,

    That may still make him the bane of your existence, of course 🙂

    Upon review, you may be right. 🙂

  66. BBD says:

    Brandon G

    Where do these people come from??

    We could ask Sartre 😉

  67. Brandon Gates says:

    Camus would tell you to not be absurd.

  68. BBD says:

    Very droll, Mr G.

  69. Brandon Gates says:

    Court jester is a role I perhaps know a little to well. Speaking of, how far do I push it at Eli’s place before I completely break character …. 🙂

  70. BBD says:

    I was just wondering the same 🙂

  71. Brandon Gates says:

    As a much younger lad, I would have fully committed. If Lars doesn’t catch “farcical charade” I’ll come clean, dammit all. 😦

  72. BBD says:

    See if you can get “facile bilge” in somewhere. That might do it.

  73. This seems to be one of those multi-blog conversations that get very confusing after a while 🙂 One thing you need to consider is Poe’s Law. If Lars has identified Brandon as kind of pseudo-skeptic, it is quite possible that it is not possible to reach a level of ridiculousness that would make it clear that you’re just pulling his leg.

  74. Joshua says:

    Posted this over at Judith’s but it may well not get past moderation (I’ve been a naughty commenter)…

    But it really is just too spectacular to not be distributed more widely:

    Is Obama Arming Iran for a Secret Reason?

    Sounds promising, right? But you really can’t appreciate how beautiful it is until you read the reasoning behind the following conclusion:

    By shifting America’s attention from Iran acquiring a nuclear bomb to helping Americans accept the much loftier goal of a small nuclear blast to remedy global warming, Barack Obama can cure the climate crisis and officially reclaim his reputation as America’s brainiest president.

    It’s got it all. Global warming. Nuclear winder. Ebul environmentalists. Obama as an America-hater. One world government. Massive starvation.

    Really! All in one article.

    http://www.americanthinker.com/articles/2015/04/is_obama_arming_iran_for_a_secret_reason.html

  75. Brandon Gates says:

    ATTP, I already fessed up. BBD’s fault — he asked a serious question I wanted to answer seriously. Thus ends my reign as a pseudo-pseudo-sceptic.

    BBD, see, I’m so motivated to not nick Russell’s lines I’d already forgotten about “facile bilge”. Damn that guy for beating me to it.

  76. BBD says:

    Laydeez an Gennelmen, a big hand for Edgar Allan Gates 😉

  77. BBD says:

    This seems to be one of those multi-blog conversations that get very confusing after a while

    Sorry ATTP. I blame BG. He made me do it. 😉

  78. Brandon Gates says:

    Joshua,

    Watts ran a similar piece by Paul Driessen recently: http://wattsupwiththat.com/2015/04/12/the-obama-climate-monarchy/

    ISIS terrorists continue to butcher people, while hacking into a French television network. Iran’s quest for nuclear weapons remains on track. In a nation of 320 million people, American businesses hired only 126,000 workers in March, amid a pathetic 62% labor participation rate. Wages and incomes are stagnant.

    And yet President Obama remains fixated on one obsession: dangerous manmade climate change.

    So it’s ostensibly a priorities argument but with dog-whistles. I dunno, props to American “Thinker” for at least having the sack to come right out and say what they’re really thinking.

    It really hacked off the WHUTTers off something fierce that I didn’t just come right out and accuse Driessen of writing propaganda. Which amused me endlessly.

  79. Brandon Gates says:

    BBD,

    (bows, motions to his supporting cast) It was a good run with some much needed levity for my part.

  80. Eli Rabett says:

    You’re banned

    Or maygee not

  81. Brandon Gates says:

    lol, typo’s bad, punctuation, botched literary references, same-team trolling … what else could go wrong today? Oh, Eli could ban me, but I might be able to work that angle ……

  82. Brandon Gates says:

    …. oh, and I could go into moderation for using a BAD word after Anders’ bedtime. You’ll understand when he wakes up.

    (sigh)

  83. Brian Dodge says:

    “That said, the ESS is *lower* in hot climate states as the cryosphere is absent or diminished and the slow ice albedo feedback is absent or diminished.” Why doesn’t the ever increasing slope of the exponential dependence of water vapor & its amplification with temperature make the ESS higher at higher temperatures?
    And what about the clathrate gun bullet holes now appearing in the Siberian tundra?

  84. Is there software to make a quiz whether a statement comes from WUWT or whether it comes from American Thinker or is simply made up?

    P.S. It could improve the level of the discussion if the term Tol were a moderation word. All in favour say Yeah.

  85. BBD says:

    VW is a *fast feedback* and so included in ECS.

    Ice albedo is a *slow* feedback and so included in the ESS.

    CH4 is a *fast* feedback and so included in ECS…

    Etc.

  86. Pingback: Red Team vs Blue Team | …and Then There's Physics

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