Guest Post by Willis Eschenbach
Andrew Lacis and the good folks at GISS have a new paper, Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature, Andrew A. Lacis, Gavin A. Schmidt, David Rind, Reto A. Ruedy 15 OCTOBER 2010 VOL 330 SCIENCE [hereinafter “Lacis10”]. Although most commenters have dismissed their work as being derivative and not containing anything new, I find that they have actually made a couple of unique and novel errors. I have two main difficulties with their paper. I have a problem with one of their theoretical claims, and I also have large issues with their model results. First, the theoretical claim. Lacis10 says:
Because the solar-thermal energy balance of Earth [at the top of the atmosphere (TOA)] is maintained by radiative processes only, and because all the global net advective energy transports must equal zero, it follows that the global average surface temperature must be determined in full by the radiative fluxes arising from the patterns of temperature and absorption of radiation. This then is the basic underlying physics that explains the close coupling that exists between TOA radiative fluxes, the greenhouse effect, and the global mean surface temperature.
Figure 1. Global Energy Budget from Trenberth et al.
Let me examine this claim one piece at a time.
They start by saying:
Because the solar-thermal energy balance of Earth [at the top of the atmosphere (TOA)] is maintained by radiative processes only …
This is not clear. What does “maintained” mean? I think they mean that on average outgoing radiation must perforce equal incoming solar radiation, which is true. As seen in Fig. 1, 341 W/m2 of incoming solar is balanced by the 102 W/m2 of reflected solar plus 239 W/m2 of outgoing longwave.
Next they say:
… and because all the global net advective energy transports must equal zero, …
“Advection” is defined by the American Meteorological Society as “the process of transport of an atmospheric property solely by the mass motion (velocity field) of the atmosphere;”
Since advection merely moves energy around, you’d think that advection wouldn’t change the average global temperature. However, while energy is conserved, temperature is not conserved. Suppose we take two equal areas, say the part of the planet from 30N to 30S (average 25°C) and the rest of the planet including the poles (average 4°C).
Advection (also called “atmospheric transport”) moves about 20 W/m2 from within the tropical and subtropical area of 30°N/S to the temperate and polar area outside of 30°N/S http://www.sp.ph.ic.ac.uk/~arnaud/PAPER/Czaja_Marshall_jas06.pdf. Using blackbody calculations for simplicity, from the 20 W/m2 energy transfer the equatorial area cools by three degrees, while the same area at the poles warms by five degrees. And as a result, the average temperature of the two areas warms by a full degree, simply from advection.
So while the authors are entirely correct to say that the net advective energy transports equals zero, the same can not be said about the effect of net advective energy transport on temperature.
However, let’s ignore that. Let’s say that both of those statements are true for the purposes of this analysis. Given those statements, they then say:
… it follows that the global average surface temperature must be determined in full by the radiative fluxes arising from the patterns of temperature and absorption of radiation.
Here’s where we really part company, on two points. First, surface temperature is not “determined in full by the radiative fluxes”. There are also sensible heat fluxes from the surface to and through the atmosphere (conduction/convection, called “Thermals” in Fig. 1) as well as latent heat fluxes (evaporation and transpiration, or “Evapo-transpiration in Fig. 1). Both of these cool the surface without changing the TOA “solar-thermal energy balance of the earth.” Either I don’t understand their conclusion, or I disagree with it. What am I missing?
Second, there is no logical “it follows” path to get from the two statements
“solar in = solar + longwave out”
and
“net advective energy transport = 0”
to their conclusion
“global average surface temperature must be determined in full by the radiative fluxes”.
I cannot think of, and they do not provide, any logical chain of reasoning that connects the third statement to the first two.
So that’s the theoretical problem with the paper. They claim that the surface temperature of the planet is “determined in full by the radiative fluxes”. I say no.
Next, the model problem. They base all of their claims on making very large changes in the variables of the GISSE global climate model. The model problem is that like many other climate models, GISSE has the cloud feedback backwards. The GISSE model says that clouds are a positive feedback. There’s a good study of the question by De-Zheng Sun et al., 2009, Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations, Journal of Climate, 22, 1287–1304 [hereinafter Sun09].
Among other things, Sun09 says:
A more serious concern raised by the study of Sun et al. (2006) is the finding of a common bias in the simulation of the cloud albedo feedback in the leading climate models: with the exception of the GFDL model, all the models they analyzed in that study underestimate the response of cloud albedo to the surface warming.
This finding from Sun 2006 were reconfirmed in Sun09. Here’s an illustration of the problem:
Figure 2. Solar (albedo) cloud feedback (blue bars), cloud longwave (yellow bars), and net cloud feedback (red bars) in models and observations of the equatorial Pacific (5°S-5°N, 150°E-250°E). Net feedback is the sum of the longwave and albedo feedbacks. Period of study 1983-2004. DATA SOURCE Sun09 Table II. See Sun09 notes for Table I and Table II for details on the data.
Note the errors in the modelled albedo feedback (blue bars). In the tropics, solar albedo feedback works as follows. Increasing warmth means increasing clouds. Increasing clouds means more sunlight is reflected into space. This cools the earth, and is a negative feedback.
While most of the of the models at least get the sign of the cloud albedo (solar reflection) feedback correct (more clouds means less sunshine hitting the earth, a negative feedback), the UKMO Hadgem1 and the GISS EH models don’t even get the sign of the albedo feedback correct. The rest of the models underestimate the size of the albedo feedback, with values as low as 16% of the observed cloud albedo feedback.
There are also a very wide range of values for the longwave, some of which are very small compared to the actual observations.
In addition to the albedo and longwave problems, a larger issue is the net cloud feedback (red bars). All but one of the models show positive net cloud feedback. The observations and one model show negative feedback.
Now, the Lacis10 authors are using their model to determine (among other things) what happens in the deep Pacific tropics when the non-condensing GHGs are removed from the atmosphere.
Obviously, the first thing that would happen if GHGs were removed is that the planet would start to cool. The immediate response in the tropics would be that daytime cumulus would decrease. This would allow more sunshine to heat the earth, which would be a negative feedback on the cooling from the lack of GHGs.
In addition, the number of tropical thunderstorms would decrease. This would slow the Equator-to Poles atmospheric transport. Once again, this would warm the earth, and would also be a strong negative feedback on the cooling.
The GISS model, on the other hand, says the opposite. It says that as the Earth cools from the lack of GHGs, the change in clouds would make it cooler yet … and unsurprisingly, it says that the net result would be that the planet would spiral into a permanent snowball. Fig. 3 is a figure from the Lacis10 paper, showing how they think it would evolve:
Figure 3. Lacis10 description (their Fig. 2) of the evolution of GISSE model when non-condensing GHGs (everything but water vapor) is removed.
I find this graph quite odd. Immediately after the GHGs are removed, surface temperature starts to drop. That makes sense. But concurrently, there is a steep increase in clouds, from 59% coverage to 69% coverage in one year. This doesn’t make sense. A warmer world is a wetter world. A warmer world is a world with more moisture in the air, and a world with more rainfall and more clouds. Conversely, a cooler world is a dryer world, with less clouds. What would cause the modelled clouds to increase in coverage as the earth cooled? This may be related to the reversed sign of the GISS albedo feedbacks shown in Fig. 2.
(In addition, the GISS Model E normally shows about 10% less cloud coverage than the real Earth. See Present-Day Atmospheric Simulations Using GISS ModelE, (PDF 2.2 Mb), page 169.)
Finally, Fig. 4 shows the atmospheric transport feedback and the total atmospheric feedback, again from Sun09. This is the net cloud feedback shown in Fig. 2, plus the water vapor feedback and the atmospheric transport feedback. (Water vapor feedback is similar in observations and models, and is not shown.)
Figure 4. As in Fig. 2, for atmospheric transport feedback (blue bars) and total atmospheric feedback (red bars). Total atmospheric feedback is the sum of the feedbacks of water vapor, cloud longwave, cloud shortwave, and atmospheric transport. Fewer models are shown than in Fig. 2, because of lack of data for the remainder. See Sun09 for details.
As with the net cloud and the cloud albedo feedbacks, the atmospheric transport feedback is also underestimated by many models. Atmospheric transport is the movement of energy out of the Equatorial area of the study. This transport of energy out of the area increases as the temperature goes up, so it is a negative feedback. It reduces the size of an expected increase.
And as a result of all of the model underestimations, the net feedback for the observations is much larger than any of the models. And indeed, some of the models go so far as to claim positive feedback in the deep tropics area studied.
So that’s my second problem with the Lacis10 paper. Given the huge variation in the feedbacks of the different models, and given that all but one of them show positive cloud feedback in the tropics, there is absolutely no reason to place the slightest credence in the GISS ModelE results reported in Lacis10. Let me close with this quote from James Hansen, pp 2-3 (bulleting mine):
2.4 Principal Model Deficiencies [of the GISS ModelE climate model]
Model shortcomings include
• ~25% regional deficiency of summer stratus cloud cover off the west coast of the continents with resulting excessive absorption of solar radiation by as much as 50 W/m2
• deficiency in absorbed solar radiation and net radiation over other tropical regions by typically 20 W/m2
• sea level pressure too high by 4-8 hPa in the winter in the Arctic and 2-4 hPa too low in all seasons in the tropics
• ~20% deficiency of rainfall over the Amazon basin
• ~25% deficiency in summer cloud cover in the western United States and central Asia with a corresponding ~5C excessive summer warmth in these regions.
I mean, how could you not trust a model with specs like that?
w.
Dave Wendt says:
December 9, 2010 at 1:15 pm
Evans and Puckrin 2006, a study which used spectral analysis to quantify the separate contributions of the various atmospheric component gases to total downwelling long wave radiation at the surface
http://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm
Interesting reference.
As you observed in a later post you have put your own interpretation rather than the authors’ . The authors’ conclusions are pro AGW so why is not not published or followed? I think it is because when doing the AGW calculations they assumed that the H2O was the same as present at pre-industrial times, whereas it rises with temperature. Maybe when they put H2O correctly in the pro AGW turned into anti AGW conclusion.
I have often said that the problem with the so called “climate science” is that they mix up systems of physics.
Thermodynamics is a self contained system and works extremely well from small heat engines to star observations.
Quantum mechanics also works very well for systems of dimensions hbar , for coherent systems ( superconductivity, superfluidity, lazers) .
Spectroscopy is a measuring devise that validates quantum mechanical descriptions, i.e. that the world in sizes of hbar works according to quantum mechanics .
The atmosphere is not a system that can display coherence ( except maybe in the ionoshere) and is par excellence to be described by thermodynamics. In thermodynamic black body radiation there is no meaning of spectral lines, it integrates over them. As much meaning as to say that in order to study turbulence one has to look at the bonds of individual molecules in the fluid . Yes, H2O maxima of absorption and emission are in different wavelengths than CO2 or methane or .. . Thermodynamic quantities could not care less, since there is overlap anyway of the spectra, and it is only the characteristic lines that stand out. Thermodynamically the atmosphere is blind to whether it is CO2 or H2O that is contributing to the so called “greenhouse” effect, and temperatures etc are all thermodynamic quantities.
“Has anyone calculated the energy input of “space dust” to our climate?”
Sure, Zero.
Earth 6e24kg
Objects 1e5kg
Let’s make them another factor of 1000, for “kinetic energy transfer”
So that makes it roughly 1e-19, or Zero for the first 18 places after the decimal point.
No one has mentioned lapse rate as a mitigation against Earth snowball effect.
The heat pump effect of daily rotation is even offered by NASA as an explanation of the unexpected warmer temperature of Neptune at its poles,( daily rotation about 16 hours) by means of equator/ polar circulation.
Dave wendt
Very nice study
“This experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming.”
Eric, the feedback from water vapor is definitely positive. The Lacis10 models get values not far from the Evans observations.
MODTRAN is a model used to estimate line-by-line radiative transference. It is online here. You need to bear in mind that MODTRAN does not include solar radiation.
In a cloud-free column in the tropics with no GHGs of any kind, surface radiation (sensor at 0 km elevation, looking up) is about 48 W/m2. Adding only water vapor to the atmosphere adds about 291 W/m2 to the downwelling. Adding only the GHGnc (CO2 and the minor gases) adds about 78 W/m2. Adding both adds about 300 W/m2.
And therein lies the problem. The sum of the two individual changes (H2O 291 W/m2 + GHGnc 78 W/m2) gives us 368 W/m2. Which is more than we get when we have both. This is because of the overlap. Both H2O and GHGnc absorb in some of the same frequencies. And MODTRAN can’t distinguish between the two sources in the combined 300 W/m2.
The Evans paper is important in this regard. It says that when relative humidity is high (most of the time in the tropics) most of the radiation is from water vapor.
In the Evans paper, GHGnc were the source of 6% of the summer clear-sky radiation (with high humidity). If that were the case here, the clear-sky radiation is 300 W/m2, so the split would be 282 W/m2 from H2O, and 18 W/m2 from GHGnc. This is physically quite possible, since H2O alone adds 291 W/m2.
Even using the straight MODTRAN calculations, however, shows that the Lacis10 claim is unlikely. The loss of the GHGnc gases gives only a 9 W/m2 change in downwelling radiation, according to MODTRAN. While this is a significant change, it is far from enough to send the planet spiraling into a snowball.
The surface is currently at 390 W/m2. For radiation balance, MODTRAN says the surface would cool by about 3°C (including water vapor feedback, but without cloud or other feedbacks).
Doesn’t sound like a snowball to me.
Baa Humbug says:
December 9, 2010 at 12:19 pm (Edit)
There’s a couple fundamental differences between ice/snow albedo feedback and cloud feedback. These are timing and location.
Timing. Cloud feedback is much faster than ice feedback. It acts in minutes, not months and years. We can watch cloud feedback at work on warm, moist summer days. When it gets warm, fluffy white cumulus clouds pop into existence, cutting down solar input. Snow/ice feedback, on the other hand, is much slower.
Location. Cloud feedback occurs around the planet. One of the most important types occurs in and around the tropics. This is the cumulus/cumulonimbus cloud feedback. It is a strong negative feedback. The majority of solar energy enters the planet in the tropics, where the sun is the strongest. Little solar energy enters the planet near the poles. As a result, any feedback occurring in the tropics will have a large effect on the climate.
Ice and snow, on the other hand, occurs where the sun is weakest and the natural albedo is the highest. Much of the snow and ice only sees a weak winter sun for a few hours a day. As a result, changes in snow and ice coverage have much less effect on the climate.
My opinion is that if the GHGs were suddenly removed, the cloud-based governing system of the tropics would immediately start changing. Clouds would form later in the day and fewer thunderstorms would form. As a result, more solar energy would be added every day to the system and less energy would be lost through transportation to the poles. This would re-establish something near the previous temperature fairly quickly, and ice/snow albedo feedback would be a minor factor.
Willis,
Another stimulating piece of work from you. I look foward to seeing it published in one of those peer-reviewed journals. They don’t all exclude good critical work on mainstream climate science, as shown by the acceptance of the new O’Donnell et al paper by J of C.
steven mosher says:
December 10, 2010 at 12:34 am
about the linked paper
Dave wendt
Very nice study
“This experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming.”
If you believe the assumptions and the model used:
from the extended abstract:
flux since the preindustrial
period. Simulations using
FASCOD3 were performed to estimate the
greenhouse flux from the various gases using
their respective tropospheric concentrations
from two centuries ago (IPCC, 1995;
Dickinson and Cicerone, 1986). Most of these
simulated fluxes have been verified with the
experimental measurements in Table 4, so
that there is some confidence that these
modelled flux increases are representative of
northern middle latitudes. In these
calculations, the amount of atmospheric
water vapour has been assumed to be
invariant.,
bold mine.
Water vapor cannot be invariant from the little ice age to now. It goes up with temperature.
In addition to all the assumptions about emissions two centuries ago.
As I said, maybe that is why it never made it to a publication in a journal.
“… it follows that the global average surface temperature must be determined in full by the radiative fluxes arising from the patterns of temperature and absorption of radiation.”
So how does this work on Venus?
With that title I took it as another report from Mexico.
That was the first paper that came to mind reading this post. I may have misunderstood the paper but it seemed to answer the question of why many scientists think CO2 is so important especially during ice ages/snowball earth periods. During such times there would be little in the way of WV and the measurements would tend more toward the winter scenario of the paper with CO2 dominant. But in the current interglacial the summer (increased WV) scenario dominates and the effect of CO2 is much reduced.
The authors seemed to skip quickly over the summer measurements in their haste to prove their point and missed the potential importance of the summer/winter difference. Having said that I only have access to the “extended abstract” so perhaps they explore this further in the full paper.
I wasn’t aware that the people at NASA GISS knew what a thermometer was and to let them play around with radiation “data”, that cannot end well at all. As my teacher in meteorology always says; “Albedo always gets ignored and plays a much bigger part than expected” we who live up here in the far north near the arctic circle where its damned dark and cold about now notice stuff like that!
Roger Longstaff says:
Having said that I only have access to the “extended abstract” so perhaps they explore this further in the full paper.
I could not find a reference to a full paper. That’s why I posted the above.
Maybe I am wrong and somebody has a reference to the full published paper?
If I’m not mistaken, about 100 tons or more of “space dust” and rocks and such enter our atmosphere every day. At the very least, there is kinetic energy transfer into the Earth’s system asthey burn up in the atmosphere.
Has anyone calculated the energy input of “space dust” to our climate?
An interesting little question. Here’s a quick answer …
m = 100 tons = 1E5 kg (your number)
v = 20 km/s = 2E4 m/s (found on internet)
A = 5E14 m^2 (for earth)
t = 86,400 s ~ 1E5 in one day
KE = 1/2 m v^2 ~ 0.5 * 1E5 * (2E4)^2 ~ 2E13 J per day
P ~ 2e13J/1e5s = 2E8 W
P/A ~ 2E8W/5E14 m^25 ~ 4E-7 W/m^2 ~ 0.0000004 W/m^2
I think we can safely ignore this contribution 🙂
Willis, Ethically Civil, Doug Badgero:
The Lacis et al argument “global net advective energy transports must equal zero…” is indeed bogus.
What I think they are trying to say (“global”) is that at the earth’s surface the air velocity is zero and therefore the advective heat flux is zero. This is true, but what happens in fact is that there is a very thin ‘boundary layer’ where heat is trasferred by conduction, before convection/advection takes over.
Consider a closed metal container completely full of water, sitting on a stove. By the Lacis et al argument, heat could never get from the bottom boundary to the top! In reality it does, of course, by convection.
To my opinion the “Global Energy Budget” is just a Kindergarten Model, which ran out of control…
… it follows that the global average surface temperature must be determined in full by the radiative fluxes arising from the patterns of temperature and absorption of radiation.
The main flaw is to equal a theoretical “radiation surface temperature” (zero height, pure radiation temperature) with a real-world measured “surface air temperature” (measured in 2 meters height in Stevenson screens in “absence of radiation” next to various heat sources).
Therefore this model is just a cartoon without impact on the real world.
And without the need to reach a surface radiation balance of 16°C, there is no need for “Back Radiation”, which makes the so called “Greenhouse Effect” pretty useless…
Willis, nice tribute to Anthony; great paper; provides lots of discussion from many different fields. WUWT is establishing THE model for peer (really serious, knowledgeable and experienced peers, not pansies) review in full view on the internet — to discuss, evaluate, correct, and add to current knowledge and research. I can’t express my feelings in words as I read a paper like yours and comments (the whole shebang) — something like pure joy.
Ron Cram (12/9 10:29 pm) brings up my question as I read through your post:
“Willis,
Nice job. I hope you publish a rebuttal to this paper in a high impact journal. There is one bit I think you have wrong. You say a warmer world is a wetter world. I’ve heard it before but I just don’t buy it.” He gives an example from the U.S. I have always wondered about the warm-wet, cold-dry “constant”, especially as I don’t think those glaciers can grow to continent size without lots of wet. I think of the extended drought in at least the western U.S. during the middle Holocene during one of the warm cycles.
Does the formula always work with strong regional variations, or is there some other “principle” at work that causes wet times and dry times regardless of temperature?
It says that as the Earth cools from the lack of GHGs, the change in clouds would make it cooler yet … and unsurprisingly, it says that the net result would be that the planet would spiral into a permanent snowball.
Eeeeeyahh. That’s the tipping point to which the precautionary principle should be applied.
ULF says ‘But it also got my mind going in a different direction. While trying to figure out why it is so desperately hard to get updates about the ARGO measurements, I came across arguments that the data from ARGO cannot be reconciled with the observed energy flux balance (or something like that).’
This lack of ARGO data is bugging me also. Could the ocean heat measurements be decreasing.? That would be awkward. Does anyone have an update on ARGO?
Ken Finney says:
December 9, 2010 at 9:43 pm
If I’m not mistaken, about 100 tons or more of “space dust” and rocks and such enter our atmosphere every day. At the very least, there is kinetic energy transfer into the Earth’s system asthey burn up in the atmosphere.
Has anyone calculated the energy input of “space dust” to our climate?
—-
Assuming a speed difference between the earth and the in falling space “dust” to be 30 km/s and assuming the estimate 100 tons/day to be correct it is very easy to calculate the kinetic energy of the dust E=1/2 mv² . The mean heating power (when spread over 24 h) generated is then roughly 500 MW (one small nuclear power plant) which sounds much but it isn’t. The solar energy falling on one square km of the earth is of the same order of magnitude (but bigger). Harry is thus correct in that the warming from the dust is totally insignificant compared to the input from the sun.
Because the solar-thermal energy balance of Earth [at the top of the atmosphere (TOA)] is maintained by radiative processes only
Are you absolutely sure?, what about, all the endothermic/exothermic chemical reactions; electromagnetic/gravity processes, what about all the spectrum?
Has some God or Prophet up there issued a decree separating each wavelength/frequency in a water tight compartment?. What if two tectonic plates move one against the other, is it not anything else but a “massage”?, etc.,etc.
“So while the authors are entirely correct to say that the net advective energy transports equals zero, the same can not be said about the effect of net advective energy transport on temperature.”
The first thing that comes to mind is that the temporal context is an essential element. The present IPCC fixation is on the most recent 100 years or so, yet in that time we have not had massive energy storage dynamics. I mean, these folks will scold the rest of us about Greenland melting away in our lifetimes, yet not seem to care a whit about the massive energy dynamic that phase change would produce.
Then there are the repeating cycle of ice age entombment of millions of square miles of land and lakes. I haven’t seen any estimates of the energy flow there.
Sure it must net to zero, but hey if the solar flux changed by just 1% during a glacial cycle, what is that energy delta?
65. John Day, thanks that was exactly what I was looking for.
Willis, the overlap seems to be the biggest problem in determining the result. My gut feel from the 30 watts indicated by John is that the cloud loss and reduction in latent heat transfer would balance that loss and the tropics would stay nicely thawed. Further north I’m not so sure. I wouldn’t just dismiss the albedo from more snow and ice. At any rate, this is an experiment that I would be very reluctant to perform on the planet, unlike the opposite experiment wherein the water vapor and cloud feedback would cap the temperature increase from NC GHG.
If the incoming photons have the energy associated the frequency range for light that is E=h v of some J s. example: 540×10^12 times 6.626 x 10^-34 = 3.58×10^19 J s.
The out going photons are of the energy associated with IR and have much lesser energy. 2×10^13 times 6.626 x 10^-34 = 1.32 x 10^-20 J s.
Just on a photon to photon basis many more IR photons must leave to make up for the decrepency in energy levels. But where did the extra ones (photons) come from?
I am not convinced that a W/m2 basis is valid given the energy levels of the incoming and out going frequencies. It is the frequency that carries the energy that gives the associated temeperature that comes from it. (Wein’s Law)