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Unforced variations: May 2014

Filed under: — group @ 2 May 2014

This month’s open thread. In order to give everyone a break, no discussion of mitigation options this month – that has been done to death in previous threads. Anything related to climate science is totally fine: Carbon dioxide levels maybe, or TED talks perhaps…

394 Responses to “Unforced variations: May 2014”

  1. 51
    DIOGENES says:

    Sidd #48,

    “I see adaptive grids in ice sheet models these days, and SOME ocean or atmosphere models using them.”

    Impressive, especially since they’ve been reported in the open literature at least since 1980 (and probably before).


  2. 52
  3. 53
    DIOGENES says:


    Good report, but Wisniewski’s assessment is right on target:

    ” “While President Obama has taken some important steps to address climate change at home, his administration is undermining that progress by ignoring the huge amounts of carbon pollution that would accompany the fossil fuel industry’s plan to export coal, liquefied natural gas and oil abroad,” said Gabe Wisniewski, Greenpeace USA’s climate and energy campaign director, in an email. “Climate change is a global crisis which will only be made worse by extracting and exporting fossil fuels, whether it’s fracked gas from Appalachia, coal strip-mined from Montana, or oil drilled from the Arctic.””

  4. 54
    Hank Roberts says:

    Chris Dudley: no discussion of mitigation here this month, see top of page.

  5. 55
    Hank Roberts says:
    is discussed at

    The report was supervised and approved by a large committee representing a cross section of American society, including representatives of two oil companies. Congress ordered in 1990 that a major scientific assessment of climate change be compiled every four years, though the administrations of Presidents Bill Clinton and George W. Bush were slow to comply with the law, and this is only the third report to have been produced.

    One of the report’s most dramatic findings concerned the rising frequency of torrential rains. Scientists have expected this effect for decades because more water is evaporating from a warming ocean surface, and the warmer atmosphere can hold the excess vapor, which then falls as rain or snow. But even the leading experts have been surprised by the magnitude of the effect.

    I’d welcome discussion of the paleo record for extreme precipitation events following rapid warming, e.g. Schmitz, Pujalte, et al.

  6. 56
    Hank Roberts says:

    for US readers, this is local:
    doi: 10.1130/G32785.1 v. 40 no. 7 p. 591-594
    Clay assemblage and oxygen isotopic constraints on the weathering response to the Paleocene-Eocene thermal maximum, east coast of North America

    Cédric M. John1,*,
    Neil R. Banerjee2,
    Fred J. Longstaffe2,
    Cheyenne Sica2,
    Kimberley R. Law2 and
    James C. Zachos3

    The Paleocene-Eocene thermal maximum, a transient global warming event, is characterized by extensive evidence of a more active hydrological cycle. This includes a widespread pulse of kaolinite accumulation on continental margins, viewed as the by-product of either enhanced chemical weathering consistent with much more humid conditions and/or increased erosion of previously deposited laterites. … the latter might be indicative of extreme seasonal precipitation patterns. To assess these hypotheses, we present a new high-resolution clay mineral assemblage and oxygen isotope record …. This finding points to accelerated exhumation and erosion of kaolinitic soils, most likely Cretaceous laterites.


    “… I’ll know my song well before I start singing
    And it’s a hard, it’s a hard, it’s a hard, and it’s a hard
    It’s a hard rain’s a-gonna fall.” == Bob Dylan

  7. 57

    This will probably have been noted by others before this appears, but what the heck? The Federal Advisory Committee report is out today:

    The main website link isn’t up to date yet, but draft chapters are available here:

  8. 58
    Meow says:

    [Mods: there was a captcha problem. Remove this if it's a dupe. Thanks!]

    @37: I also don’t see how that can be so, if you compare the forcings in a globally-averaged annual manner. Globally-averaged annual Milankovitch forcing over the last 1M years has been ~ +- 0.3Wm-2 [1] (though it’s much larger at 65 degrees N.: ~ +- 55Wm-2 [2]), whereas near-present (2005) net globally-averaged anthropogenic forcing is ~1.6Wm-2 [3].

    [1] Laskar et al, “Insolation of the Earth from -20 Myr to +10 Myr”,…270..522L . , at Fig. 4.

    [2] Ibid at Fig. 5.

    [3] AR4 WG1, s.TS.2.5, at Fig. TS.5

  9. 59
    sidd says:

    Re: Forcing difference between stade and interstade

    I believe the reference is to total forcing. An estimate for the difference between last glacial maximum and preindustrial from the Alfred Wegener Institute may be found here

    GHG -2.8, dust -1.4, ice sheets -3.0, vegetation -1.2, for a total of -8.4W/m^2

    Hansen et al. estimate around -6 for GHG + albedo in “Climate Sensitivity, Sea Level, and Atmospheric CO2″


  10. 60
    sidd says:

    “they’ve been reported in the open literature at least since 1980 (and probably before).”

    Oh. My. God. Has anyone told Manabe this ?

    More seriously, my question remains, is anyone doing lagrangian approaches ? i wasn’t necessarily asking about going all out lagrangian, since one does have to deal with inconveniences like terrain boundary conditions, but more like a comoving grid with some intelligence about the BCs.


  11. 61
    Killian says:

    [edit - OT]

  12. 62
    Killian says:

    58 Meow says @37: I also don’t see how that can be so, if you compare the forcings in a globally-averaged annual manner. Globally-averaged annual Milankovitch forcing over the last 1M years has been ~ +- 0.3Wm-2 [1] (though it’s much larger at 65 degrees N.: ~ +- 55Wm-2 [2]), whereas near-present (2005) net globally-averaged anthropogenic forcing is ~1.6Wm-2 [3].

    [1] Laskar et al, “Insolation of the Earth from -20 Myr to +10 Myr”,…270..522L . , at Fig. 4.

    [2] Ibid at Fig. 5.

    [3] AR4 WG1, s.TS.2.5, at Fig. TS.5
    - See more at:

    Thanks for the math, Meow, but I wish people would realize simple logic is often enough for a forum discussion on certain points: Milankovitch 182 – 298, Homo Destructus 280 – 402. Temps following.

    We win.

  13. 63
  14. 64
    Buck Smith says:

    Gavin sorry for double posting basically the same comment. Thanks for your thoughts in response. I think ice age forcings are relevant because an ice age will be a lot worse for the planet than warming.

  15. 65
    Edward Greisch says:

    From the course at
    there is a really great table of word substitutions to make when talking to non-scientists. Do tables copy? No.

    Terms that have different meanings for scientists and the public

    Scientific term Public meaning Better choice
    enhance improve intensify, increase
    aerosol spray can tiny atmospheric particle
    positive trend good trend upward trend
    positive feedback good response, praise vicious cycle, self-reinforcing cycle
    theory hunch, speculation scientific understanding
    uncertainty ignorance range
    error mistake, wrong, incorrect difference from exact true number
    bias distortion, political motive offset from an observation
    sign indication, astrological sign plus or minus sign
    values ethics, monetary value numbers, quantity
    manipulation illicit tampering scientific data processing
    scheme devious plot systematic plan
    anomaly abnormal occurrence change from long-term average

    Just convert it back into a table. This is from a lecture by Richard Somerville on communicating climate science. The course is from UC San Diego.

  16. 66

    So, assuming this El Nino doesn’t fizzle out

    The question really comes down to whether ENSO is deterministic and predictable, or chaotic and largely unpredictable.

    A sinusoidally perturbed wave equation (the Mathieu equation) models the seemingly chaotic ENSO as a quasi-periodic waveform:

    This is one of those phenomenon that should exist if ENSO is being described as a “sloshing” of the Pacific ocean’s waters. So its not surprising that it matches the experimental observations so well given the known inertial changes in the earth’s rotation.

  17. 67
    Chris Dudley says:

    Stanford has decided to divest its coal stocks and will consider doing more. Divesting from companies pursuing unconventional oil should be next.

    The article says Stanford is the first large University to do this. That is true for US universities. Cambridge in the UK decided to divest some time ago.

  18. 68
    Chris Dudley says:

    Editor @63,

    Discussion of fossil carbon pools is part of climate science. It is separate from discussion of mitigation methods. Is discussion of adaptation off topic?

    [Response: This isn't a game show so please stop trying to legalistically get around some rule. There is no rule, it's simply that discussion of mitigation/adaption/renewables/nuclear etc. just ends up repeating itself all the time, with the same people and the same lack of engagement with anyone else - it gets boring. So just talk about something else that is actually climate science related here, or set up your own blog with a focus on exactly what you want to talk about. Thanks - gavin]

  19. 69
    Pete Best says:

    Lets talk about personal emissions:

    Who here has worked it all out what they emit in Co2 terms?

    My household does 4 tonnes per annum in Co2 from automobiles (60 MPG diesel motors), 9 tonnes per annum from burning gas (heating and cooking) and around 1 Tonne from electricity usage (2000 KWH per year) and as I dont fly much at all (2 times in 5 years)and then from everything else around a couple of tonnes. Lots of carbon calculators around. I have been able to reduce my consumption and have measured it over a few years to see if I have managed to get my emissions down. I have also invested in wind turbines to offset my electricity usage.

    I reckon that makes my household around 17 tonnes per year, way to high really. I know people in houses who consume 20 tonnes in heating and cooking alone per house let alone everything else.

    We are way to high and that states a lot for even at just 8.5 tonnes for me its still way to high and yet the highest in society will have emissions over 100+ tonnes each from all of their activities. Worrying really as China are coming on and consuming more and hence the west needs to consume a lot less. Economics is based on growth and hence emission cuts is deemed to impact that and hence not much is being done. Sure renewables are growing and fast but its not fast enough to stop 1.5-2C which is 450 ppmv for a 50/50 chance of reaching that.

    Its a lot of pontificating going on and a lot of politics is being talked but on the basis of what is actually needed from Annex and non Annex 1 countries the pain is going to be felt by them but caused by us it would seem. When will the world peak its global emissions, certainly not whne all of the great and the good reports are looked at. Here in the UK our CCC independent climate assessors were saying 2016 and now its 2020 and hence the window closes whilst humanity needs another round of global meetings to agree how to prevent 2C whilst it might well be its a 4C world they are actually talking about.

    Something very political is going on and although its advised by science its not the science that is truly represented but a ghost of it, one that gives hope to politicians but is not based on reality.

  20. 70
    Chris Dudley says:

    Gavin @68,

    Perhaps I’m being a bit too discursive then. I’m interested in discussion surrounding fig. 25 in your paper “Efficacy of climate forcing” again.

    There you and your coauthors state:

    “The efficacy diagram extended over a large range of
    forcings should have vertical upturns at both the small
    forcing and large forcing ends, corresponding to the snowball
    planet and runaway greenhouse instabilities. Indeed, the
    snowball earth instability is evident for [about] 20% So and there
    is a hint of the runaway greenhouse at 8 [times] CO2. The
    upturns are expected to be sharper and to occur at smaller
    forcings for longer timescales. Numerical problems in
    model parameterizations have hindered more complete
    exploration of the extremes of the efficacy diagram.”

    In “Storms of my Grandchildren” the models appear to have been extended to 16 times CO2 in fig. 30 there. And I recall you are unsure of it was Ruedy or Sato who conducted those runs, but it was not you. I seem to be discovering that nearly 32 times CO2 is accessible owing to technological advances not previously considered in this context. Extrapolating the Efficacy from 16 times CO2 to 32 times CO2 by eye in fig 30 of “Storms” suggests as much as a doubling of climate sensitivity at that high forcing. Does that extrapolation seem like it has any merit at all?
    Are the numerical problems in the models being addressed so that they may cover plausible BAU scenarios?

    Catchpa: specially artHot

    [Response: It's not really a question of numerical problems, but rather a progressively increasing violation of underlying assumptions. For very high CO2 (> 10x), radiative approximations need to be changed (to include CO2-CO2 collisions for instance), atmospheric thermodynamics changes (molecular weight of air, expansion coefficients, etc.) and total atmospheric mass increases. Each of these require work to incorporate (and this is being done), but it isn't trivial to do. - gavin]

  21. 71
    DIOGENES says:

    Pete Best #69,

    Mitigation discussions are disallowed on this thread. I have responded to your comments on the Apr 2014 Unforced Variations thread.

  22. 72
    Meow says:

    @59: But during a Milankovitch cycle, only the change in insolation is a forcing. The other changes are all feedbacks, and the theory thus postulates that the climate (in at least some states) is quite sensitive to changes in insolation at 65 degrees N.

  23. 73
    Susan Anderson says:

    ot alert: Boston area Fort Point Open Studios this weekend; please introduce yourself (see local press for info). Some good environmental projects around here these days. For example:

  24. 74
    John Mashey says:

    “I think ice age forcings are relevant because an ice age will be a lot worse for the planet than warming.”

    Just out of curiosity, ignoring possible nuclear wars or major asteroid strikes, or stopping CO2 emissions tomorrow, does anyone here think there is a significant chance of Earth returning to ice age depths in:
    - next 1,000 years
    - next 10,000 years
    - ever, as long as there is a technical civilization that can produce SF6 or similarly-strong GHGs?

    If so, have they read David Archer’s The Long Thaw or Bill Ruddiman’s Earth Transformed, Ch 17? and can they offer evidence for rejecting their analyses?

  25. 75
    Hank Roberts says:

    > personal emissions: … what they emit

    After that, work out the other side of the balance sheet, what you capture.

    The online calculators aren’t much use for that, yet: acres x inches of topsoil, over a lifetime, isn’t simple to calculate, but it’s about the simplest carbon capture anyone can accomplish. Find a patch of neglected ground, buy it, learn what can live there, help its recovery.


  26. 76
    Hank Roberts says:

    Where the carbon goes on its way to subduction
    links to a description of the sea floor by someone who has seen a lot of it. That’s one of several very informative posts from a discussion thread at Metafilter about what is involved in finding that lost aircraft.

    Brief excerpt follows:

    . Near areas without a clear sediment source, carbonate can accumulate to form huge platforms which in turn shed parts like crazy. And let’s not forget icebergs, which drop huge blocks of sediment, boulders, rocks, and dirt, all into the ooze of the sea floor, where they mush the sediment in fascinating ways and then get buried.

    In other parts of the deep ocean, sediment accumulation occurs from the “pelagic rain” which is a mixture of clay and plankton. Depending on the currents, nutrients, and temperature of the water, this rain can be mostly silica based plankton, calcareous plankton, some clay, or mostly clay (comprised of particles like volcanic ash, dust, and sometimes meteorite particles). And fish feces, which may turn into something else on the way down and once buried (if you see rocks that are completely green, like the Greensands of England, and it’s not volcanic, it’s proably full of a mineral called glauconite and indicates the presence of a lot of organisms that produced feces.) It can take years for a particle to reach the bottom of the ocean, and sediment accumulation rates can vary from millimeters to 2 centimeters every thousand years.

    Not only that, all that happens and then gets buried and affect future accumulation. Faults may dictate accumulation and sediment flow, and then be buried themselves or still be active. And let’s not forget our old friend erosion. And salt. Oh how buried salt affects the sea floor. It’s all yummily complex.

    In some areas, sediment accumulation is poor due to location (many parts of the Pacific Ocean, for example, where trenches along the edge trap a lot of sediment), lack of accumulation space (i.e. a basin) or oceanic currents, preserving much of the original sea floor topography from its birth. And let’s be clear here: oceanic crust was born in fire, and it moves. It moves all over the place, inches a year sometimes. 20 million years ago it may have been near a continental plate and the recipient from the sediment from a river, and now it may be the middle of the ocean without any currents or pelagic rain, but carrying along on its seamounts a dirty white line called the Carbonate Compensation Depth (CCD), or “marine snow” from when it was close enough to something to support plankton…almost lonely, really.

    And not only does oceanic crust move, it ages. (As does the water it carries – imagine how old some of the water in the deepest, quietest part of the ocean must be.) The oldest crust in the Pacific, aged from the Jurassic at 180 million years old, is almost at the end of its life (ocean crust is created, then destroyed, and then created again in what’s called a Wilson Cycle, which lasts ~200 m.y.). As it ages, it may experience (near the edges of basins and topographic high spots) erosion and sediment accumulation as sea level goes up and down (never underestimate the amount of erosion that can occur during a sea level rise and fall).

    So – this crust in this part of the world ranges from young to old – it ranges from ~40-81 million years old on the 90 East Ridge to mid Cretaceous near Australia @100 m.y. – and has been strongly affected by movement of Australia, India, and Antarctica. A sediment accumulation map of the area shows sediment depths of 0-500 meters once you leave the coastline of Australia, although that map is a little suspect because this area is very tectonically active and sediment accumulation may be less because of basalt build-up. The 90 East ridge - that large line extending north towards India – is a series of seamounts from the Indian plate passing over a hotspot (much like Hawaii) on its speedy path towards colliding with Asia. The Australia-Indian plates are (proposed to be) currently spreading apart and there are several fracture and baby spreading zones in the area, creating a complex topography of ridges and trenches, as well as submerged continental crust.

  27. 77
  28. 78

    Can’t assess the technical aspects of this paper on sunlight and the tree-ring ‘divergence problem’, but conceptually it’s pretty neat. And the results are certainly of interest:

  29. 79
    GlenFergus says:

    sidd @ #60 etc:

    Hahaha … some people need to learn to play nice. Langrangian grids have also been used for decades in one corner of one of my areas of interest: soil and rock mechanics. Reasons there might parallel some in ice mechanics: local properties need to move precisely with any material flow / failure (and often depend intimately on the local history). Presumably those benefits don’t apply in mixing fluids like the atmosphere and oceans. Maybe there are also serious computational penalties, although FLAC (linked above) has always had a reputation for speed. (It’s just the name: Fast Lagrangian Analysis…)

  30. 80
    MARodger says:

    Levitus quarterly OHC has now updated to March 2014. Both 700m & 2,000m continue to show an upward curve in the 5-year rolling averages, as graphed here (usually 2 clicks to ‘download your attachment’).

  31. 81

    #50–Which brings up another interesting (though hardly novel) point.

    If the prediction of advancing blossom dates were purely statistical, then sure–the advance now is not that much more dramatic than that in the 20s, undercutting its statistical significance. (Though presumably also strengthening the correlation between earlier blooming times and warmer temperatures.)

    However, the prediction of further advance can also rest on the basis of physical process–specifically, GHG forcings known to be increasing over time.

  32. 82
    DIOGENES says:


    Interesting perspective on Methane (

    The takeaway:

    “By comparison, under business as usual human fossil fuel emissions combined with amplifying feedbacks from the Earth climate system (such as those seen in the fens now forming over thawing Arctic tundra), total warming could spike to an extraordinarily damaging level between 5 and 9 degrees Celsius just by the end of this century.”

  33. 83
    Chris Dudley says:

    Gavin @70,

    raypierre seems to like trying a few possibilities for including self-broadening. Is that the approach you are taking as well? The heavier atmosphere would seem to give more distance over which the lapse rate can play which would boost climate sensitivity.

    Speaking of raypierre, I think he feels that increased scattering makes a CO2 tipped runaway impossible, you’ve got to wait for the Sun. Yet increasing sensitivity still means otherwise higher temperatures at 32 times CO2. I hope you can see now that even though renewable energy is often discussed in relation to mitigation, under normal economic considerations (what would be profitable?), it would actually make much larger fossil carbon pools available owing to its falling cost and fossil carbon’s convenient reduced form. That should motivate climate modeling efforts that can speak to the effects of applying renewable energy to fuel synthesis through enhanced fossil carbon extraction.

    Such modeling efforts are relevant to present day policy issues such as development of Green River oil shale or tar sand pipeline decisions. People often complain about biofuel mandates, yet requiring an ever increasing fraction of our fuels come from atmospheric or dissolved carbon rather than fossil carbon seems like a necessity if renewable energy is going to make a helpful rather than hurtful contribution. Without the mandates, we get BAU on renewable steroids and five rather than three doublings of carbon dioxide.

  34. 84
    Thomas says:

    Glen@79. The issue with Lagrangian is that for fluid or even highly distorted solids the grid gets so badly twisted out of shape as to be useless. Think about coffe and cream mixing in a stirred cup. There are hybrid methods, like ALE, which try to get the best of both. But they have their drawbacks.

  35. 85
    GlenFergus says:

    Thanks Thomas, guess that’s what I expected. Further to sidd’s thought bubble, another might go something like: why not formulate the problem in (non-Lagrangian) finite elements instead of finite difference. I’m sure that’s occurred to plenty of others, who’ve managed immediately to dismiss it, for reasons my ignorance obscures.

    (Vastly increases discretisation complexity, to what purpose? Most obviously, modern FE codes do automated, on-the-fly, mesh refinement to suit local gradients … and its opposite. Substantial benefit might accrue if you could make your GCM put calculation nodes right where the current circulation pattern needs them, and not where it doesn’t. It mightn’t be all that hard to try; there are commercial generic FE codes that’ll solve just about any combination of differential equations you specify, in any geometry.)

    [Response: Folks have been playing w/ spectral element approaches for some time. see e.g. Baer et al (2006) "Climate Modeling with Spectral Elements" -mike]

  36. 86
    sidd says:

    Thanks, everyone. I had forgotten that the z co-ordinate in some ocean models is lagrangian. Agreed, the distortion of of a lagrangian co-ordinate system makes computation intractable quickly, but we retain path(history) information in the distortion of the grid and a measure of Kolmogorov mixing so we pay a price for that. Perhaps the ALE routines are smart enuf now to use lagrangian in low-mixing flows, and switch to eulerian elsewhere. I don’t know how much this buys you, i have the impression that a lot of cycles go to recomputing meshes.

    Another corner in my thought bubble was the fact that in (soil mech) interfaces between two media, the less compliant one is sometimes modelled with lagrangian picture, and i was thinking about ice and water. Unfortunately the phase transition close by complicates things, a solid in contact with its melt is complex (though fascinating), even without all those twisty bits in the water ice transition. A long time ago, in a different life, i worked on similar systems, and my hat’s off to those who are doing so today. Speaking of which, I see that NEGIS models are coming along


    open access at

    All the usual suspects, including Csatho, who was seeing dimples over Peterman Canyon in 2006. They do something called algorithmic differentiation to invert a cost function for modelled and measured surface mismatch, which would have been impossible a couple decades ago, both because we didnt have the data, and because we didnt have the CPU/bandwidth. Check it out, amazing how far brute computational force coupled with physical insight can get you.


  37. 87
    Killian says:

    Story on the HANDY model and a soon-to-be-published paper predicting…. what we already know is happening, But, nice for some formal science to step up and confirm collapse isn’t just a fringe issue and that climate, indeed, is a player.

    NASA, Irreversible Collapse Study

    It’s been being said for decades – Catton, Holmgren and Mollison, Club of Rome, and update in 2005, et al. – but maybe people will listen to this since it is more “serious” science?

    But… the “elite” typically don’t listen:

    Applying this lesson to our contemporary predicament, the study warns that:

    “While some members of society might raise the alarm that the system is moving towards an impending collapse and therefore advocate structural changes to society in order to avoid it, Elites and their supporters, who opposed making these changes, could point to the long sustainable trajectory ‘so far’ in support of doing nothing.”

    Now, don’t I feel special? Destined to be ignored, and happening in real time.

    While the article doesn’t cover it explicitly, climate virtually always plays a role in any societal collapse. Economic growth is the biggest destroyer of the ecology.

    NASA Concludes When Civilization Will End

    Those people who think you can have a growing economy and a healthy environment are wrong. If we don’t reduce our numbers, nature will do it for us … Everything is worse and we’re still doing the same things. Because ecosystems are so resilient, they don’t exact immediate punishment on the stupid.

    It would be nice to see some climate-based analogies for the issue of growth. Is there anything in the math, the systems that easily lends itself to the discussion of the limits of systems in size, longevity, use of available inputs? Hurricanes, e.g., need a certain amount of heat. Is there anything aobut some of these cliamtic systems that better helps us understand the nature of limits within the physical system of the planet?

  38. 88
    Chris Colose says:

    Chris Dudley (83)-

    I can agree climate sensitivity increases by the time you get to 32x CO2 (see e.g., Russell et al., 2013). One of the reasons for this is simply that the forcing goes up a bit faster than a log function much beyond 1000 ppm or so, but also because that model (and others) give stronger water vapor and high cloud feedbacks in such a regime.

    But there seems to be a lot of stability in 3-D models against a runaway, even moreso than in the 1-D models that have dominated the literature on this topic, since the dynamics still keep parts of the globe well subsaturated in a very hot atmosphere. The updated absorption coefficients in such climates (neglecting clouds) decrease Earth’s albedo at high water vapor concentration since it effectively absorbs solar radiation that would otherwise be reflected, but with clouds my take on this is that even removing most of the low clouds from the current climate would probably not trigger a runaway (as a sensitivity study, Coldblatt and Zahnle showed removing all low clouds doesn’t even resolve a faint young Sun, and you probably need more solar increase to trigger a runaway than that).

    I’m certainly not going to speak for raypierre, but I think the intuition is that in a very moist atmosphere, clouds can only exert a strong greenhouse effect if they are extremely high in the atmosphere, and so the scattering effect probably wins out. That’s not a statement about feedback though. At this point though, I don’t think anyone has an idea what clouds do in such climates, but I still don’t think there’s a plausible way to change albedo enough to trigger a runaway.

  39. 89
    Chris Dudley says:

    Chris (#88),

    Thanks for the reply. That helps. I wonder if you could write up a realcimate post on that paper since it is paywalled?

    I wish the realcimate archive were working.

    [Response: Sorry - hadn't noticed the problem. Fixed now. - gavin]

    We could look back more easily at raypierre’s thoughts on this. I think he was invoking Rayleigh scattering as a barrier against a CO2 tipped runaway regardless of clouds.

    An issue gavin mentions is the increased mass of the atmosphere. This further raise the altitude from which radiation escapes to space and gives the lapse rate a longer run to work on so that surface temperature is higher and sensitivity is higher. Is this effect included in Russell et al?

  40. 90
    Ray Ladbury says:

    Mark Twain had a bit to say on peoples’ tendencies to extend linear projections indefinitely:

    “In the space of one hundred and seventy-six years the Lower Mississippi has shortened itself two hundred and forty-two miles. That is an average of a trifle over one mile and a third per year. Therefore, any calm person, who is not blind or idiotic, can see that in the Old Oolitic Silurian Period, just a million years ago next November, the Lower Mississippi River was upwards of one million three hundred thousand miles long, and stuck out over the Gulf of Mexico like a fishing-rod. And by the same token any person can see that seven hundred and forty-two years from now the Lower Mississippi will be only a mile and three-quarters long, and Cairo and New Orleans will have joined their streets together, and be plodding comfortably along under a single mayor and a mutual board of aldermen. There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.”–Life on the Mississippi

    The comfortable are reminiscent of the man who fell of the 100th floor of a building and was heard, as he passed the 50th floor, to say, “So far, so good.

  41. 91
    Dave Peters says:

    Some food price implications of the drought in California are starting to emerge.
    Although it is still early, and detailed data on the extent to which enhanced well pumping and crop insurance programs will interact to affect yields remains murky, the current estimate of fallowed acreage in the Central Valley is 12%, or 800 thousand acres. National food price inflation is still forecast to remain “normal”, at between 2.5% to 3.5%, for 2014 overall, but particular price stresses are already registering and anticipated to linger for beef and dairy. Some price-inelastic vegetables such as avocados and lettuce could hike by ~30%, with others such as broccoli by ~15%, and grapes and tomatoes by perhaps 10%. (The USDA opened a web site on April 16 to monitor affected markets, at:

  42. 92
    Chris Colose says:

    Chris Dudley-

    Yes, in the Russell paper both CO2 and water vapor add to atmospheric mass, and the dry gas constant and specific heat are modified accordingly. The resulting temperature profiles as a function of height are shown here…you can see the increase in atmospheric pressure in the last few runs.

  43. 93
    Chris Dudley says:


    Thanks, that helped. Chris, here is a portion of the discussion from back then.

  44. 94
    John Mashey says:

    UC Santa Cruz Climate Science & Policy Conference, Feb 28-Mar 1, 2014.

    Videos now available.

    This was a really fun conference to attend.
    1) UCSC is of course a beautiful campus, set amidst the redwoods.

    2) Good speakers.

    3) Very important: mix of climate and social sciences, something I hope to see more of.

    I hope they do more like this.

  45. 95
    Chris Dudley says:

    Chris (#88)

    Reading back a little, I think raypierre was not saying regardless of clouds, but rather was looking to see if cloud behavior could help to drive a runaway beyond cloudless models and was coming up with: not easily if at all. In a cloudless model, as the atmosphere gets more massive, Rayleigh scattering increases, increasing albedo, providing stability against runaway for a while. Attempted CO2 tipping does not overcome this so it must be increased radiative forcing to notch up to the runaway point.

    So, in the Efficacy paper, the increase in sensitivity at 8 times CO2 is an increase in sensitivity, alright, but not an indication of the start of a runaway.

    Hopefully, that gets to the core of that issue.

    The increased sensitivity, though, is interesting in its own right.

  46. 96
    Chris Dudley says:

    Chris (#92),

    Thanks for that link. It seems to be that the sensitivity going from control to 16 times CO2 and from 16 times CO2 to 256 times CO2 is about the same. Perhaps there is a bulge? The biggest individual step seems to between 16 and 32 times CO2. Looks like about 9 C per doubling there compared to slightly less that 3 C at the first doubling. That seems to support my extrapolation of fig. 30 in “Storms of my Grandchildren.” but continued steeper extrapolation would not be supported.

  47. 97
    DIOGENES says:


    Received this in the mail today; anyone familiar with this issue? Does it have the significance the reporter states?

    “At the elevated levels of atmospheric carbon dioxide (CO2) anticipated by around 2050, crops that provide a large share of the global population with most of their dietary zinc and iron will have significantly reduced concentrations of those nutrients, according to a new study led by Harvard School of Public Health (HSPH). Given that an estimated 2 billion people suffer from zinc and iron deficiencies—resulting in a loss of 63 million life years annually from malnutrition—the reduction in these nutrients represents the most significant health threat ever shown to be associated with climate change.”

  48. 98
    Chris Dudley says:

    Further to my #32, now that the archive is available, I’ve found a reckoning of carbon feedbacks here:

    In #26 we’re counting as much a 1000 GtC of clathrates as fuel rather than feedback, but that may leave 9000 GtC as a feedback. In addition to the 2000 GtC of soil carbon mentioned in #32, there may be 4000 GtC in known permafrost and (unknown) ice sheet covered surface carbon. Together that comes to 15,000 GtC available for feedbacks. So, that is somewhat more than the factor of 10 case in #26. Together, we get to 5.8 doublings rather than 4.6 doublings.

    In the figure Chris linked, the smallest sensitivity per doubling occurs between 32 and 64 times CO2 so all the feedback carbon together may lead to just a couple C of warming if the BAU on renewable energy steroids scenario releases as much fossil carbon as possible. It appears that renewable energy can make carbon feedbacks fairly unimportant in terms of warming when counted in this manner. Feedbacks could be a complication if renewable energy is used with ethical considerations in mind, but purely economic use together with the low climate sensitivity where feedback carbon comes into play may make them only the frosting on the life destroying cake.

  49. 99
    Wally says:

    9 May 2014 An international team of scientists estimate that up to half of the recent global warming in Greenland is caused by natural climate variations.
    The research, published today in the journal Nature, sheds new light on the rapid melting of Greenland’s glaciers. Crucially it indicates that global warming caused by carbon dioxide emissions may not be the only factor responsible.
    Dr Ailie Gallant from Monash University said these natural variations stem from an unusually warm tropical Pacific Ocean, east of Papua New Guinea. This “sweet spot” is partly responsible for Arctic warming.
    The team used observations and used advanced computer models to reveal that a warmer western tropical Pacific Ocean has caused atmospheric changes over the North Atlantic, warming the surface by about half a degree per decade since 1979.
    What remains unknown is whether the enahnced warming in Greenland will continue.
    Professor John Wallace from the University of Washington said that if ocean surface temperatures in the Pacific changes, it could result in a reduction in the amount of warming in Greenland.
    “Ice is exquisitely sensitive to temperature, more than we ever would have thought. Natural variations could either accelerate or deaccelerate the rate of melting of Greenland’s glaciers in coming decades, but in the long run, the human induced component is likely to prevail,” Professor Wallace said

  50. 100
    deconvoluter says:

    Re: Les Chevaliers de l’Ordre de la Terre Plate, Part II: Courtillot’s Geomagnetic Excursion:

    How can this be accessed in the English translation please?

    It appears to have flipped languages while I was using it.

    (a). This issue is being hyped by the GWPF and James Delingpole.
    (b) Raypierre’s article was very good.
    (c) Courtillot does not appear in RC Wiki.

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