Our WUWT thread on Antarctic Sea Ice Losses has spurred quite an interesting discussion. Dr. Robert G. Brown of the Physics Department at Duke University responds to a comment on ice albedo with a summary of water vapor action, the greenhouse effect, and the chaotic nature of the atmosphere. He ends with his view of why he’s not a betting man.
Well worth a read.
phlogiston: I do realise that over the Antarctic land mass albedo from surface snow is anomalously higher than that from cloud, since the snow presents such a pure white surface. However this is probably not the case for sea ice whose surface is more irregular and cracked with patches of dark sea in between.
The trouble is that water vapor is literally a two-edged sword. As vapor, it is the strongest greenhouse gas in the atmosphere by (IIRC) around an order of magnitude, so increasing water vapor can and does measurably increase the GHE — a lot, when considering dry air versus saturated air. In arid deserts, temperatures skyrocket during the day and plummet at night because of the absence of a water vapor driven GHE — CO_2 alone isn’t nearly enough to keep upward facing surfaces from rapidly losing their heat due to radiation. In very humid tropical climates, the nights are consistently warm because of the GHE.
However, water vapor is also the mediating agent for two major cooling mechanisms. One is the bulk transport of latent heat — sunlight and LWIR hit the sea surface and cause rapid evaporation of surface molecules of water. Wind blows over the ocean surface, stripping off water molecules as it goes. This evaporated water has a huge heat content relative to liquid water — the latent heat of vaporization. As the warm water vapor is carried aloft by convection, it carries the heat along with it. It also cools as it rides the adiabatic lapse rate upward, and further cools by radiating its heat content away (some of which returns to the Earth as GHE back radiation). Eventually the partial pressure of water vapor in the moist air becomes saturated relative to the temperature and the dew point is reached, making it comparatively probable that the water vapor will recondense into water. In order to do so, though, several things have to be “just right”. The water vapor has to be able to lose the latent heat of vaporization that it picked up at the water surface when it evaporated. The future water droplets have to be able to nucleate — which is a lot more likely to occur when there are ionic aerosols in the atmosphere as water (a polar molecule) is attracted to bare charge of either sign.
Once a water droplet is nucleated and grows past a critical size (that depends weakly on humidity and temperature) its surface becomes large enough that growth due to increased surface deposition outweighs loss due to surface evaporation, and the droplet stabilizes as a single droplet of condensation in a cloud or continues to grow to fall as rain. Either way the water, now high in the troposphere and hence through most of the optically opaque greenhouse layer, releases heat that is “short circuited” through the greenhouse mechanism and lost to space via radiation.
The cloud, as you note, has a very high albedo. High albedo means that it strongly reflects short-wave (e.g. visible) radiation without ever absorbing it and being heated by it. During the day, clouds outside of the polar regions act as a cooling agent, reflecting sunlight before it has a chance to reach the ground and lower troposphere to warm either one. During the day and the night, however, the cloud also acts as a powerful greenhouse blanket, directly reflecting LWIR as well as visible back down towards the Earth’s surface. In the tropics, daytime reflection wins by a landslide — reducing the incident sunlight by a huge fraction for a large fraction of the day beats the comparatively small modulation of surface radiative losses both day and night. In the temperate zone (again, IIRC) albedo still wins, but by a smaller and smaller margin as one creeps north (and in ways that are increasingly dependent on seasonal weather patterns — in the winter clouds can easily be net warming where in the summer they can be net cooling).
However — and this is key and the reason I’m replying to you — in the polar regions clouds are generally net warming, at least most of the year. You’ve already indicated some of the reasons — the polar regions are already often or permanently ice covered, and the gain in daytime albedo from clouds vs ice is not so great. The real problem, however, is that nighttime warming from the enhanced GHE from clouds scales with the fraction of the day that it is nighttime, and of course inside the arctic circles that can be as long as 100% of it. High albedo doesn’t cool when there is no incident sunlight to reflect, and even in the arctic summer, the sun comes in at a substantial angle so that direct solar warming is weak (so that clouds can reflect only a proportionally smaller amount of heat). A lot of polar temperature is determined by heat transport, not direct heating, explaining the substantial difference in mean temperatures of the North and South poles. In the north, there is substantial heat transport and heat exchange via the ocean; in central Antarctica there is only the atmosphere to carry heat in from the warmer latitudes and it just can’t do the job half as well.
That’s why I hesitated to assign a sign to the net feedback from any sort of local modulation of e.g. ocean-air humidity or sea ice coverage. The processes are COMPLEX and can have either sign, and they are NON-LOCAL as adding humidity in one place can increase albedo someplace else thousands of miles away is it finally concentrates enough to form clouds. A large part of the rain that falls over North Carolina comes up from the Gulf of Mexico maybe 1000 miles away. Some of it comes all the way over from the Pacific, where some of that might have originated in e.g. the growing El Nino. Heat from the tropical Pacific can be transported all the way to NC before it finally releases its heat and falls as rain, before it finally creates clouds that cause NC to cool after helping to greenhouse warm much of the surface area it crossed in between.
This is the kind of thing that the models are supposedly trying to model, but they perforce replace all of the small-length scale detail of this description with presumptive averages over cells 100-300 km square (where weather phenomena such as thunderstorms are order of 1 to 10 km square, where the details of front structure and development are much finer than this). They are excruciatingly tuned to aerosol levels and albedo — they have to be to stabilize anywhere near the correct/observed temperatures and preserve the central tenet that CO_2 causes X amount of baseline warming that is on average augmented by additional water vapor.
This last assumption is finally dying a quiet and well deserved death. AFAIK, it is due to Hansen, who in his original papers predicting disaster assumed universally positive water vapor feedback (and for no particularly scientifically motivated reason that I can see, hypothesized truly absurd levels of water vapor feedback that doubled or tripled the CO_2-only warming of his then very simple models). Naturally, some of the GCMs out there have built into them parametric assumptions that preserve this much “climate sensitivity” — total ACO_2 warming plus feedback, usually at the expense of an overdriven response to e.g. volcanic aerosols necessary to explain periods of global cooling and to keep the model from having a runaway exponential instability (because one has to have a mechanism that keeps positive feedback water vapor from causing increase of water vapor without bound just from FLUCTUATIONS in water vapor content or global temperature — the climate cannot be a biased random walk where every time the temperature goes up a bit, average water vapor increases and hence resets the Earth’s average temperature a bit higher unless a competing process can completely erase the gain when the temperature fluctuates down a bit).
At the moment, estimates of climate sensitivity are struggling to retain any net positive feedback from water vapor in the face of data that already solidly excludes the kind of absurd feedback levels Hansen originally hypothesized. Even the question of net negative feedback from water vapor, long considered to be anathema in climate science (except for a few mavericks who managed to publish papers suggesting that clouds could easily lead to net negative feedback through the dual mechanism of latent heat transport and modulation of albedo) is no longer completely off of the table. I don’t know that people will start to take it too seriously unless/until the Earth actually cools (several tenths of a degree, sustained, not just vary up or down or weakly downward trend) but obviously if this happened it would truly be the only likely catastrophe associated with global warming to all of those that have invested their professional careers, hundreds of billions of dollars of global wealth, and their political and/or scientific reputation on shaky claims in poor agreement (so far) with observational data.
IF there is a super-ENSO, perhaps it will help their arguments survive a bit longer, or perhaps it will truly kick up the temperature to where the models become believable again. Perhaps not. ENSO is not the only factor in climate evolution, and while it has been dominant for the last half century or so in mediating positive jumps as documented by Bob Tisdale, its ability to do so could easily be predicated by the phases and states of the other decadal oscillations, the state of the Sun, the state of baseline vulcanism, the immediate past climate history, and the price of tea in China. A chaotic nonlinear system can be quasiperiodic and apparently causal for a while and then for no computable reason change to an entirely different mode of behavior where a significant quasiparticle/process becomes insignificant and some other process becomes the critical driver. We could still watch as the developing ENSO discharges all that heat in such a way that it never manages to raise global average temperatures by much because of some confounding wave that causes the heat to be efficiently transported up and quickly lost rather than persisting to spread out over the globe at high altitude, or by a mere modulation of the winds that causes albedo over the warm(ing) patch to be higher than expected so that the delivery of solar energy to the ocean is effectively interrupted. It’s not like we can properly predict ENSO (although we can do pretty well with forward projective hindsight once an ENSO process has started).
No matter what, I expect the next year to be highly informative. If we have a super El Nino that heats the planet by 0.3C very rapidly, that certainly makes GCMs more, not less, plausible on average as it kicks global average temperatures at least in the right direction for them not to be as egregiously wrong as they currently appear to be. If it only kicks the temperature up by 0 to 0.1 C, and that only transiently so that temperature in a year are again pretty much flat relative to 1998-2000, it is very bad news for the models. If it fizzles altogether — short-circuited, perhaps, by the downhill side of solar cycle 24 that maybe be beginning and which will proceed with poorly predictable speed and which may or may not have a competitive local effect on the climate and produces no gain at all and cycles immediately into a cooling La Nina that augments any solar cycle cooling to actually drop global average temperatures, that too will be very informative.
Personally, I won’t even place a bet. I don’t think the climate is computable, which means that I think one is basically betting on the output of a (possibly biased) random number generator. I’d rather play Mumbledy-peg for money.
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Hunter,
I took it to mean he was rounding up, both to be conservative and to make mental calcs easier.
milodonharlani:
You packed a lot of utter falsehoods into one sentence! The models don’t ignore water vapor effects other than radiative, they don’t ignore evaporative cooling, convection currents, and reflection off & shading by clouds. Essentially, nothing in this sentence is correct. It is a work of complete fiction.
The concern about global warming has nothing to do with the runaway greenhouse effect. If we believed a runaway was at all likely, we would have to take much more draconian measures than the tiny baby-steps to very gradually wean ourselves off of the fossil fuels that those stuck in a 19th century mindset seem to love so much.
Pre Che/Earthday science this was the “consensus” and it didn’t require frat party hazing or Mao reeducation camps to enforce. Not computable means models are worthless since the inputs are random variables.
Think of the jobs, profits and political power that would not have consolidated in the hands of the AGW advocacy elite? Think of the benefits if the billions and billions (trillions when we consider excess energy cost pushs) had remained in the hands of private citizens or had been spent on rational collective research instead? A 40 year ongoing crime in progress and still counting.
@Alan Watt
Dr Brown has a page, here:
http://www.phy.duke.edu/~rgb/
AlecM says:
I have yet to see a real heat transfer expert (including a lot of skeptics like Robert Brown) who believes there is any merit whatsoever to your arguments.
Dr. Brown… a question.
Having previously read of the need for aerosols for nucleation to facillitate rainfall, I have often wondered what the source of nucleation would be in the case, say, of rain lasting for several weeks. After the first day or so of rain one might expect that the local atmosphere would be mostly clear of aerosols; what would then be the possible sources of nucleation for the continuing rainfall?
Tom Billings says:
May 21, 2014 at 1:51 pm
The Arctic was open ocean not only in the Eocene, but as recently as the Pliocene, when maybe not Doug fir but a typical boreal spruce-larch-fir-hemlock forest skirted it.
I assume you refer to the Arctic Ocean Azolla Event, c. 49 million years ago, which allegedly led to a reduction in CO2. This however didn’t cause the deterioration in climate after the Paleocene-Eocene Thermal Maximum. CO2 is an effect of Phanerozoic climate change, not an important cause. Atmospheric CO2 fell during the Eocene because of a cooling climate. The reduction didn’t cause the temperature drop.
Then, as noted above, Cenozoic glaciation began when Antarctica was isolated by deep oceanic channels from the nearest other continents at the Eocene/Oligocene boundary. More extensive glaciation occurred in the Pleistocene. You are right that the so-called Holocene is just another of many interglacial warmer phases in our presently Icehouse climate.
Is the climate computable?
NO.
Next dumb question.
Thank you Dr Brown for a very interesting summary of the problem of clouds.
@Michael 2: re GHGs and heating/cooling the Earth.
IPCC ‘science’ wrongly considers IR Irradiance, its ‘Forcing’ is a real heat flux. It isn’t, being the potential energy flux of that emitter to a sink at absolute zero. It interacts with surface irradiance as the vector sum of all upwards and downward Poynting vectors, the monochromatic travelling waves which give ‘radiation pressure’.
Since for all self-absorbed GHG bands, their amplitude is black body level, they mutually annihilate the same wavelengths of black body surface IR. 1.0 surface emissivity and, accounting for the ‘atmospheric window’, 0.6 atmospheric emissivity means net surface emissivity would be about 0.4 if there were no parallel convection and evapo-transpiration.
The theoretical maximum net IR would then be 158.4 W/m^2 for 16 deg C, close to the 160 W/mm^2 solar SW thermalisation. however, because activated surface sites can transfer energy to adsorbed gas molecules, liquid water molecules or leave as IR, the surface temperature equilibrates so conduction, evapotranspiration and net IR add up to SW IN. The real 63 W/m^2 net IR is 40% of 160 W/m^2 so ‘operational surface emissivity’ is c 0.16.
This level is set by the GHE, determined essentially by clouds. It’s c. 11 K, from the no-GHG average surface temperature for 341 W/m^2, 4 to 5 deg C. So, it’s not GHGs setting surface temperature directly, the action is by clouds, liquid water at the surface and convection kinetics.
A planet with no atmosphere has a much wider temperature range mainly because it has no clouds!
Read Naomi Oreskes’, yes the very same, paper on why climate models are not useful beyond their use as tools to explore hypotheses and can never be truly validated.
http://www.likbez.com/AV/CS/Pre01-oreskes.pdf
@joeldshore:‘ I have yet to see a real heat transfer expert (including a lot of skeptics like Robert Brown) who believes there is any merit whatsoever to your arguments’
My arguments are standard physics. No-one has ever been able to dispute them except by claiming a pyrgeometer measures a real IR energy flux when it is really the Irradiance, a potential energy flux. What’s more important, I can show my arguments to be true by using MODTRAN which most if not all Climate Alchemists accept as having been proven by comparison with real observations.
It calculates Irradiance at any plane in the atmosphere for UP and DOWN directions. Subtract Irradiance, atmosphere to surface, from Irradiance, surface to atmosphere and you get the real net IR flux surface to atmosphere. For humid, temperate zones, it’s about the same as the measured average 63 W/m^2, 2 parts atmospheric window, one part non self-absorbed H2O bands.
So, do you still think 333W/m^2 ‘back radiation’ adds to the 63 W/m^2 net IR to give 396 W/m^2 real IR flux from the surface, which when you add 97 W/m^2 convection/evapo-transpiration makes 493 W/m^2,. 3x reality?
Or will you accept that the real IR energy flux is 63 W/m^2 and the 97 W/m^2 convection/latent heat makes up the 160W/m^2 SW thermalisation to conserve energy? I’m an engineer and the Climate models, a perpetual motion machine, are very wrong indeed which is why they fail.
I would have thought polar regions don’t have day and night rather they have day or night
Even so, one can (or could, when Intrade was active) make money by betting on Intrade’s futures-market setup, where the odds self-adjusted to the level of enthusiasm of the bettors. Warmists would typically be too sure they were right about future warmth and drive the odds too far beyond randomness. So one could win by taking the opposite side.
joeldshore says:
May 21, 2014 at 2:03 pm
You are apparently unfamiliar with the programming & design GCMs. Please educate yourself before accusing anyone of falsehoods. Or at least show a model that takes those non-radiative effects of water vapor into account. You won’t because you can’t.
The proof is in the pudding. The GIGO GCMs have failed utterly even to forecast global T years ahead, let alone the century for which their trough-feeding proponents falsely claim skill. The models also produce patterns not observed at all. They are indeed worse than worthless tautologies, which commit the logical fallacy of begging the question, ie assuming what they set out to demonstrate.
Nick mentioned runaway, so I replied. Instead of his hypothetical one degree water vapor feedback for each degree of warming from CO2, the actual figure has been shown by observation to be much less & in some environments negative. Arrhenius himself wrestled with this problem, which the CACA advocates who now take his name in vain have ignored.
No steps, baby or otherwise, are justified on the basis of the worse than worthless GCMs upon which so much wealth has been wasted, at such cost to economic development & in fact loss of life.
Dr. Brown: “the climate cannot be a biased random walk where every time the temperature goes up a bit, average water vapor increases and hence resets the Earth’s average temperature a bit higher unless a competing process can completely erase the gain when the temperature fluctuates down a bit”
Although I do appreciate Dr. Brown’s efforts, the results are occasionally too impressionistic for me, the preceding excerpt being an example. Although I, too, find positive water-vapor feedback implausible, I don’t quite understand the ratcheting he seems to imply here.
Suppose we start with an open-loop “one-box” system defined by the equation dy/dt = ax – by, where x is the stimulus, y is the response, and a and b are positive constants. If we then add positive feedback f so that the input x’ after feedback equals = x + fy, then the system remains stable so long as af < b. In fact, it has the same form of system equation, dy/dt = ax – b'y, where b' = b – af. That is, positive feedback extends the time constant (1 / b) but doesn't necessarily result in instability.
Presumably Dr. Brown had a different type of system in mind, but the above-quoted excerpt doesn't make clear just what that might have been.
Tester says:
May 21, 2014 at 2:59 pm
In between the long permanent day night, the polar regions have both day & night of varying lengths, as do temperate zones (& to a lesser extent tropical), just more extreme in variation.
I’d be interested to read more about how on Earth aerosols can be juggled to prevent the runaway instability of the IPCC’s ridiculous positive water vapour feedbacks.
Joel:
PS: Reading this might help jump start your educational process. IPeCaC itself on the problems with modeling clouds:
http://www.ipcc.ch/ipccreports/tar/wg1/507.htm
“Handling the physics and/or the parametrization of clouds in climate models remains a central difficulty. There is a need for increased observations. J. Mitchell highlighted the challenge in a recent paper at the World Climate Research Programme (WCRP) Workshop on Cloud Properties and Cloud Feedbacks in Large-scale Models where he stated that �Reducing the uncertainty in cloud-climate feedbacks is one of the toughest challenges facing atmospheric physicists� (Mitchell, 2000).”
The situation hasn’t improved because the modelers don’t want to have to try to include clouds, which would gut the lies they tell their political paymasters. Instead more money gets spent on yet more GIGO models instead of being wisely spent trying to improve the data, which in its science sections but not its summary for politicians it calls for.
Dr.Norman Page
Your video :
“Believing Six Impossible Things before Breakfast, and Climate Models.
by Christopher Essex, Ph.D.”
should definitely be more widely known and seen as it is a simply brilliant deconstruction of all climate models. After seeing this presentation, it seems that the climate science community and those scientists that acquiesce or concur have a lot to answer for.
Another superb contribution from Dr. Brown. I totally agree – I’ve said all along that we shouldn’t even be wasting time – let alone money – on trying to model something chaotic like the climate.
AlecM says:
May 21, 2014 at 2:55 pm
@joeldshore:‘ I have yet to see a real heat transfer expert (including a lot of skeptics like Robert Brown) who believes there is any merit whatsoever to your arguments’
My arguments are standard physics.
>>>>>>>>>>>>>>>>>
They are no such thing, they are pure bullsh*t, and when two PhD physicists from rather divergent points of view on the larger issues both say the opposite to the drivel you spout, the audience ought pay attention. Your yammering is distracting from the real physics being discussed, it is confusing to new comers to the discussion, and the pathetic whining about pyrgeometers is a regurgitation of the misinformation on the topic spouted by Doug Cotton and the Slayers. They’ve been banned from this forum, and you should be too.
RGB is my favorite commenter here. Thank you, Dr. Brown.
Dr Robert G Brown;
As others have already said, please keep commenting. I learn something from you ever time and your ability to take some of the most complex physics there is and explain it in a such concise manner is appreciated and intimidating all at the same time 😉
EForster says:
May 21, 2014 at 3:22 pm
Appropriate that Lewis Carroll (Charles Lutwidge Dodgson), author of “Alice’s Adventures in Wonderland”, was an Oxford mathematician, Lecturer at Christ Church. He wrote almost a dozen books based upon his work in geometry, linear & matrix algebra, mathematical logic & recreational math(s). Dodgson developed new ideas in linear algebra (eg. first printed proof of the Kronecker-Capelli theorem), probability & studying elections (eg. “Dodgson’s method”) & committees.