Assessment of Equilibrium Climate Sensitivity and Catastrophic Global Warming Potential Based on the Historical Data Record

Alex Hamilton.
I’ve been saying much the same thing about the lapse rate for some time.

Given that the temperature record seems to be continually adjusted (some may say tampered with) to effectively cool the past and warm the present, then this estimate of climate sensitivity to CO2 is likely to be an over-estimate.
Moreover, other work published on this site: http://wattsupwiththat.com/2010/03/08/the-logarithmic-effect-of-carbon-dioxide/
would also suggest that the ealier years of the graph would skew the result towards a higher estimate of sensitivity, given we might expect any further impact of increased CO2 emissions to be lower than for say 1850 to 2014.

Jeff,
How does your analysis and assumptions jive with what we do know about climate sensitivity?
We know that we get about 340 W/m^2 average power coming into the atmosphere and that about 30% is reflected/scattered away, leaving 70% to be absorbed which leaves us with 239 W/m^2 average that does get absorbed and must be balanced with what is radiated away from Earth. The average T of Earth is about 288.2K which leads to a surface emission of about 390 W/m^2 (stefan’s law).
Since what is radiated must be about 239 and what leaves the surface is 390, the atmosphere must absorb 390-239 =~ 150 W/m^2 over and above what it emits to space. Also, if we had an albedo of 0.30 without an atmosphere blocking any outgoing surface radiation, our mean surface temperature would have to be ~ 255K. That gives us an average sensitivity of (288-255) / 150 W/m^2 = 33/150 = 0.22 Deg C per W/m^2. Also, having an atmosphere ‘block’ 150 W/m^2 out of 390 W/m^2 means that about 62% of surface radiation (including what the atmosphere radiates beyond what it absorbs) actually makes it into space through the atmosphere.
Analysis of CO2 absorption in the standard atmosphere (clear skies only) results in about 3.7 W/m^2 increased atmospheric absorption for a doubling from around 370 ppm. This leads to a co2 doubling sensitivity of about 0.8 deg C.
Doing a small perturbation to T – increasing the surface T to compensate for the added co2 absorption we’d need 3.7/62% = 6 W/m^2 additional leaving the surface. This corresponds to 289.7 K average T versus 288.2 K or a rise of ~ 1.5 deg C. This is using Stefan’s law and the amount of power increase (assuming clear skies again) needed to balance a slightly more opaque atmosphere. If we apply the 0.22 sensitivity number, we see that 6W/m^2 would only need an increase of 1.3 deg C. The difference suggests a negative feedback. However, the 3.7 W/m^2 co2 factor is only valid for clear skies and less than half of the sky is clear as cloud cover tends to run close to 62%.
The catastrophic gw bunk comes from hansen and his pals. While they like to claim their fancy global coupled models are showing us the warming, reading the fine print shows something a bit different. Turns out they are using one dimensional modelling and assumptions, some perhaps dubious, about the details of clouds. Essentially, they exaggerate the results and assumptions always in the direction of more warming. Their warming comes from the resulting conclusion that added co2 and warmer conditions will result in more water vapor in the air but fewer clouds being formed. This means that since cloud cover drops with lower T, it must also drop with higher T and that means that Earth can never have 100% h2o vapor cloud cover if you are to believe hansen and his pal lacis, the 1-d modeling guy.
BTW, water vapor is quite similar to co2 in effect – both are virtually log factors with h2o being about twice the total effect and twice the effect of doubling. That means slight increases in h2o vapor content have very little effect and the shift of RH over small temperature ranges is also quite small. That is doubling does get you around 2 – 2 1/2 times the effect of co2 but a 5 deg C rise in atmospheric column temperature doesn’t get you beyond a 30% increase in absolute humidity (what counts) keeping the RH constant. Consequently, h2o cannot provide the killer positive feedback needed to raise the T.
Meanwhile, back at the ranch – we have no acceptable record of Earth’s albedo to come close to comparing with the TSI records. However, the factor that really counts is power absorbed, TSI * (1 – albedo), not TSI. Even more unfortunate is unlike Mars or the Moon, our albedo is 75% dependent on clouds and atmospheric factors and only around 25% dependent upon the surface – which is over 2/3 water. You can tell where these CAGW clowns are from when they spout off about albedo variations mostly being caused by human induced land use changes.

If the global climate debate between skeptics and alarmists were cooked down to one topic, it would be Equilibrium Climate Sensitivity to CO2 (ECS) , or how much will the atmosphere warm for a given increase in CO2 .

I disagree. That is not where the real argument is.
The CAGW theory assumes that humidity and clouds amplify the warming due to CO2 by a factor of three: extra CO2 warms the ocean surface, causing more evaporation and extra humidity. Water vapor, or humidity, is the main greenhouse gas, so this causes even more surface warming. You can also add in the energy transport from latent heat of evaporation and convection too. So all these effects are bundled up and shoved under the rug called CO2 effect.
It is clearly stated by Rich Green a physical chemist:

…Water is an extremely important and also complicated greenhouse gas. Without the role of water vapor as a greenhouse gas, the earth would be uninhabitable. Water is not a driver or forcing in anthropogenic warming, however. Rather it is a feedback….
http://how-it-looks.blogspot.com/2010/03/infrared-spectra-of-molecules-of.html

This thinking is backed up by NASA:

NASA: Water Vapor Confirmed as Major Player in Climate Change
Water vapor is known to be Earth’s most abundant greenhouse gas, but the extent of its contribution to global warming has been debated. Using recent NASA satellite data, researchers have estimated more precisely than ever the heat-trapping effect of water in the air, validating the role of the gas as a critical component of climate change…
With new observations, the scientists confirmed experimentally what existing climate models had anticipated theoretically. The research team used novel data from the Atmospheric Infrared Sounder (AIRS) on NASA’s Aqua satellite to measure precisely the humidity throughout the lowest 10 miles of the atmosphere. That information was combined with global observations of shifts in temperature, allowing researchers to build a comprehensive picture of the interplay between water vapor, carbon dioxide, and other atmosphere-warming gases.
“Everyone agrees that if you add carbon dioxide to the atmosphere, then warming will result,” Dessler said. “So the real question is, how much warming?”
The answer can be found by estimating the magnitude of water vapor feedback. Increasing water vapor leads to warmer temperatures, which causes more water vapor to be absorbed into the air. Warming and water absorption increase in a spiraling cycle.
Water vapor feedback can also amplify the warming effect of other greenhouse gases, such that the warming brought about by increased carbon dioxide allows more water vapor to enter the atmosphere.
“The difference in an atmosphere with a strong water vapor feedback and one with a weak feedback is enormous,” Dessler said…..

Two of the most important drivers of the earth’s climate are the sun and water, yet the backa$$wards thinking of these CAGW modelers is that a miniscule addition to the amount of CO2 in the atmosphere (~40ppm) is DRIVING 1,386,000,000 cubic kilometers (332,519,000 cubic miles) of water.

Here is a lesson. If you want to argue that sensitivity as a metric makes no sense or makes unwarranted assumptions.. nobody is going to listen to you. Thats voice in the wilderness stuff. You are outside the tent pissing in.
Steve, sadly, sensitivity as a metric makes no sense and makes unwarranted assumptions, whether or not anybody listens to me.
What sensitivity “should” be is the partial integral of the partial derivative of the global average temperature with respect to the carbon dioxide concentration. What sensitivity “is” is the voodoo-estimated global average temperature anomaly expected in the year 2100 from all causes. It is, in other words, completely misnamed, and for all practical purposes not computable.
Not computable? Did I say that? Sure I did. First of all, one cannot compute the global average temperature anomaly, not even with GCMs. One can only compute the global average (surface or otherwise) temperature, in degrees Kelvin. None of the physics — the Navier-Stokes equation, the various full-spectrum radiation formulae, phase transitions and albedo, latent heat, cloud dynamics — runs on any sort of “anomaly”. It requires initialization from and subsequently computes the temperature field, in depth, for every (silly) latitude/longitude pseudocartesian cell on the extremely non-flat surface of the globe for as many layers/slabs as the model descends into the ocean and into the atmosphere in addition to the “surface”.
The problem is, we do not know the temperature field. We do not know the actual average surface temperature of the planet within one whole degree Kelvin either way, and our knowledge of the surface temperature is better than our knowledge of the temperature field in depth. Perturbed parameter ensemble runs of the various CMIP5 models fairly clearly indicate that the future 100 year integrations of climate are highly “sensitive” to tiny perturbations of the initial conditions in degrees Kelvin, ones that more or less preserve some assumed starting temperature. They don’t even begin to explore the true range of uncertainty in just the initial temperature field, and one imagines that differences in the average of a degree might make major differences in 2100 absolute temperature prediction.
Finally, we have no way if “separating” the so-called sensitivity in the anomaly into natural vs anthropogenic components, because we do not know how to hindcast even the last 155 years with the models of CMIP5. They collectively fail to hindcast HADCRUT4 (with many of them failing worse than others, but none of them doing particularly well). CMIP5 completely misses the entire mostly natural cooling/warming pattern of the early 20th century, so it is not really that surprising that it overattributes the nearly identical warming of the late 20th century to anthropogenic cases.
Maybe. We really don’t know. The errors in HADCRUT4 or the other surface temperature measures are substantial and grow rapidly as one goes back in the past. Perhaps the CMIP5 MME mean is — inexplicably, given its complete lack of theoretical statistical foundation — dead on the money and it is HADCRUT, GISS, and so on that are wrong. Eventually the future will play out and maybe we will learn, just as we’ve been learning from the entire interval after the CMIP5 reference period (and before the reference period) that the CMIP5 models are failing badly — so far.
However, model by model, the prediction of the mean global average surface temperature in 2100 is not sensitivity to anthropogenic CO_2 because it contains an unknown admixture of natural warming and, in general, the models one at a time are doing a terrible job at predicting almost the entire climate period outside of their reference (training) set. The models themselves tell us that they cannot be trusted to the extent that we can compare their predictions to actual data. At this time we Do Not Know if the climate is very insensitive to additional CO_2, with natural feedbacks largely cancelling, or if The Hansen Story is true, and natural feedbacks strongly augment the warming due to additional CO_2. We don’t even know if either scenario is written in stone, or if one or the other are equally possible due to vagrant random fluctuations or unknown internal dynamics associated with e.g. decadal oscillations or in the event that there really is some sort of connection between solar state and climate outside of the small variation in direct forcing.
We do know that Hansen’s oft-and-highly-publicly-stated beliefs in extreme “sensitivity” (or total warming from all sources and causes) are probably wrong at this point — the actual climate is way off the tracks that any of the models that come close to this extreme sensitivity produce when their initial conditions are perturbed. We even know that the CMIP5 MME mean is probably wrong at this point, and that the total warming from all sources is going to end up being less than the 2.7ish degrees C it produces, understandably since it still contains all of the egregiously failed CMIP5 models in its equally weighted average. AR5, chapter 9, admits all of this — while carefully omitting any mention of the uncertainties in the SPM and “magically” transforming a mean that has no meaning whatsoever derived from the theory of statistics into “confidence” in the SPM.
In the end, as a matter of fact, we don’t know what the climate will do in/by 2100. We don’t even have a good idea.
rgb

Dr Burns says: @ur momisugly February 13, 2014 at 2:53 pm
…..I wouldn’t be surprised if Law Dome has also been faked.
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The CO2 data is as manipulated as the temperature data:

… Callendar was able to set a baseline of about 290 ppmv by rejecting values deviating more than 10% from his desired value.
It was believed that snow accumulating on ice sheets would preserve the contemporaneous atmosphere trapped between snowflakes during snowfalls, so that the CO2 content of air inclusions in cores from ice sheets should reveal paleoatmospheric CO2 levels. Jaworowski et al. (1992 b) compiled all such CO2 data available, finding that CO2 levels ranged from 140 to 7,400 ppmv. However, such paleoatmospheric CO2 levels published after 1985 were never reported to be higher than 330 ppmv. Analyses reported in 1982 (Neftel at al., 1982) from the more than 2,000 m deep Byrd ice core (Antarctica), showing unsystematic values from about 190 to 420 ppmv, were falsely “filtered” when the alleged same data showed a rising trend from about 190 ppmv at 35,000 years ago to about 290 ppmv (Callendar’s pre-industrial baseline) at 4,000 years ago when re-reported in 1988 (Neftel et al., 1988); shown by Jaworowski et al. (1992 b) in their Fig. 5.
Siegenthaler & Oeschger (1987) were going to make “model calculations that are based on the assumption that the atmospheric [CO2] increase is due to fossil CO2 input” and other human activities. For this modelling they constructed a composite diagram of CO2 level data from Mauna Loa and the Siple (Antarctica) core (see Jaworowski et al., 1992 b, Fig. 10). The data from the Siple core (Neftel et al., 1985) showed the “best” data in terms of a rising CO2 trend. Part of the reason for this was that the core partially melted across the Equator during transportation before it was analysed (Etheridge et al., 1988), but this was neither mentioned by the analysts nor the researchers later using the data (see Jaworowski et al., 1992 b). Rather it was characterized as “the excellent quality of the ice core” and its CO2 concentration data “are assumed to represent the global mean concentration history and used as input data to the model” (Siegenthaler & Oeschger, 1987). The two CO2 level curves were constructed to overlap each other, but they would not match at corresponding age.
In order to make a matching construction between the two age-different non-overlapping curves, it was necessary to make the assumption that the age of the gas inclusion air would have to be 95 years younger than the age of the enclosing ice. But this was not mentioned by the originators Siegenthaler & Oeschger (1987). This artificial construction has been used as a basis for numerous speculative models of changes in the global carbon cycle….
http://www.co2web.info/ESEF3VO2.htm

An example of present day manipulation, note the cherry picking of values, is outlined by Mauna Loa Obs. The Lab sits on top of an active volcano (fumes) near an ocean full of living things.

4. In keeping with the requirement that CO2 in background air should be steady, we apply a general “outlier rejection” step, in which we fit a curve to the preliminary daily means for each day calculated from the hours surviving step 1 and 2, and not including times with upslope winds. All hourly averages that are further than two standard deviations, calculated for every day, away from the fitted curve (“outliers”) are rejected. This step is iterated until no more rejections occur.
How we measure background CO2 levels on Mauna Loa.

It is a very nice way to get a small standard deviation in your data and get rid of any pesky results that do not fit the ‘Cause’
This reminds me of the same manipulation we see in the temperature data where the temperature from the few and far between truly rural stations is adjusted UP to match the more plentiful airport and city stations.

HenryP, do you have temp graphs from other land masses bordering the Arctic Ocean?
I understand that the poles have less accurate measurements, including by satellite for various reasons. Although I think Ocean oscillations, in particular the Pacific are most significant contributors to ice melt and freezing, it would be interesting to see if there is a consistent lag between land temps and Arctic melt and freeze.

Bill Illis says: @ur momisugly February 13, 2014 at 4:05 pm
Mosher says “Hansen for example relies on Paleo data.”
Let’s take the last glacial maximum and Hansen’s estimates based on that (and he actually wrote a paper on it). Temps were -5.0C lower, CO2 was at 185 ppm….
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If the CO2 was really 185 ppm during the ast glacial maximum then we would not be here. (Based on the ASSumption of CO2 is uniform throughout the atmosphere.)

Plant photosynthetic activity can reduce the CO2 within the plant canopy to between 200 and 250 ppm… I observed a 50 ppm drop in within a tomato plant canopy just a few minutes after direct sunlight at dawn entered a green house (Harper et al 1979) … photosynthesis can be halted when CO2 concentration aproaches 200 ppm… (Morgan 2003)
link

…Plants use all of the CO2 around their leaves within a few minutes leaving the air around them CO2 deficient, so air circulation is important. As CO2 is a critical component of growth, plants in environments with inadequate CO2 levels of below 200 ppm will generally cease to grow or produce… http://www.thehydroponicsshop.com.au/article_info.php?articles_id=27

“Does this mean that future CO2 emissions won’t be harmful? No. That’s true only if you think that the downward variations are going to strengthen to compensate for the increased CO2. IOW, all that Joe showed is that the past CO2 emissions may have been helpful or neutral, not that future emissions will also be.”
This is true but you need to consider what its likely to mean in the context of the next century or two. There’s a plank to CGW that is often missed- not only does it have to be caused by man-made carbon, and harmful, and catastrophic.. it needs to be so in a timeframe whereby heavy CO2 production both remains essential to human society, and technology hasnt advanced enough to either neutralize or mitigate the CO2 or its effects. IE- even a 1:1 ECS would be catastrophic over a long enough time frame (for that matter cotton candy production would be catastrophic over a long enough time frame). What a manageable ECS tells us is that there won’t likely be catastrophic (or even harmful) results in the timeframe such that it matters. Even without considering the advance of technology, fossil fuels would eventually diminish thereby diminishing CO2 production. That tells us that there is a finite volume of CO2 production in our future. The only thing relevant is if some concentration in the next century or two is truly dangerous. But the idea that we’ll be burning coal in 200 years is hard to swallow… barring some bigger catastrophe that sets civilization back (or perhaps some economic lunacy). The analogy of shutting down 18th century NYC out of concern for mounting piles of horse dung given population projections is always cogent.
With warmists, you always have to keep your eye on the ball. Catastrophic global warming is the only warming that means anything to anyone but climate scientists.

I don’t have any reason to criticize Jeff’s analysis; he explains what he did.
I have a basic distrust of particularly the HadCRUT data set, that is I don’t believe the data itself. John Christy et al showed that ocean water and ocean air temperatures are not the same and are not correlated (why would they be, given ocean currents and wind speeds).
So I don’t believe any data earlier than about 1980 when the Ocean floating buoys were put out there, or thereabouts.
And I also believe that the ocean evap / vapor / cloud /precip water cycle is in full negative feedback control of the whole system; which doesn’t mean there is no variation; just no catastrophic consequence. The system forward amplifier gain (if any) cannot be very high, so we can’t expect the stability common with electronic feedback systems.
Peter Humbug did an experiment on his play station where he removed ALL of the water from the atmosphere; so no vapor, and no clouds, and then let his gizmo run. He got all the water back in three months. As I recall he reported this in a peer reviewed paper in SCIENCE, but I may have the wrong journal. (I actually read his paper in the Journal). I think he would have had the same result if he had removed all of the CO2 as well.
I don’t believe that the earth would be a frozen ice ball if it had no atmospheric CO2.
My reason is that the solar blow torch that warms the earth is 1366 W/m^2, NOT 342 W/m^2, and at the surface, that becomes maybe 1,000 W/m^2, not 250 W/m^2.
Maybe after sunset, the dark earth is radiation all the time at whatever Trenberth’s number is, but during the daylit hours, when the surface is being cooked by 1,000-1366 W/m^2, it is also hotter and simultaneously radiating much more than 390 W/m^2 for a 288 K black body rate.
Take ALL of the GHG out of the atmosphere and the ground level TSI, would be closer to 1366 W/m^2, (less blues sky scattered), and we would get bags of water in the atmosphere in a big hurry; even if you started with a frozen ice ball.