Friday
May132016
by 
Bishop Hill
Bishop Hill How low can ECS go?
May 13, 2016 Climate: sensitivity A new paper in a journal called Earth and Space Science says that effective climate sensititivity could be as low as 1°C. Here's the abstract.
Estimates of 2xCO2 equilibrium climate sensitivity (EqCS) derive from running global climate models (GCMs) to equilibrium. Estimates of effective climate sensitivity (EfCS) are the corresponding quantities obtained using transient GCM output or observations. The EfCS approach uses an accompanying energy balance model (EBM), the zero-dimensional model (ZDM) being standard. GCM values of EqCS and EfCS vary widely [IPCC range: (1.5, 4.5)°C] and have failed to converge over the past 35 years. Recently, attempts have been made to refine the EfCS approach by using two-zone (tropical/extratropical) EBMs. When applied using satellite radiation data, these give low and tightly-constrained EfCS values, in the neighbourhood of 1°C. These low observational EfCS/two-zone EBM values have been questioned because (a) they disagree with higher observational EfCS/ZDM values, and (b) the EfCS/two-zone EBM values given by GCMs are poorly correlated with the standard GCM sensitivity estimates. The validity of the low observational EfCS/two-zone EBM values is here explored, with focus on the limitations of the observational EfCS/ZDM approach, the disagreement between the GCM and observational radiative responses to surface temperature perturbations in the tropics, and on the modified EfCS values provided by an extended twozone EBM that includes an explicit parameterization of dynamical heat transport. The results support the low observational EfCS/two-zone EBM values, indicating that objections (a) and (b) to these values both need to be reconsidered. It is shown that in the EBM with explicit dynamical heat transport the traditional formulism of climate feedbacks can break down because of lack of additivity.
Predictably, our scientivist friends don't like it, but it's interesting to see that there are still a few hardy souls who are willing to say what they think.
Reader Comments (142)
Waiting for the dust to settle on this paper. Real reviewing happens when all the peers get a go.
In the meantime, does anyone think ECS is constant (assuming it is real)?
And why?
Personally, I doubt ECS is real; if it is, it is probably negligible. What so many fail to realise that there could be a great many influences involved of which we have yet no knowledge – or, perhaps, no means of measuring or monitoring, even if we were aware of them. Is all the incoming energy the electro-magnetic form we call “light” (visible or otherwise)? When you consider that the Earth is constantly being battered by a solar wind that could wipe us out in seconds, and the only defence against this is the magnetic shield that Earth has, perhaps it should be borne in mind that this should also be considered an energy source, but one that we have little, if any, understanding of, never mind measuring, so the very idea on blaming the whole farrago on a tiny proportion of the atmosphere does make that idea look rather … well …pathetic, really.
Anyhooo… Jo Nova addresses, expands and explains this (and also has moving pictures to go with it) far more eloquently than I have managed; go have a look.
In the meantime, does anyone think ECS is constant (assuming it is real)?
And why?
May 13, 2016 at 9:18 PM M Courtney
Or single valued?
"In the meantime, does anyone think ECS is constant (assuming it is real)?
And why?"
I don't know.
What I do know is that some things catch me by surprise. Like the snows of Kilimanjaro reducing due to sublimation.
I also know that if the sublimation idea meant we had to make drastic changes, I would have been sceptical.
I like my science to inform me. not to guide me.
ATTP,
Paul_K,
I have read the damned paper. Equation 3, and the two zone versions of that Equation (5 and 6) are essentially assuming that the energy uptake, and the subsequent warming, is externally forced. Q' is the unit-area external forcing. Do you want to try and answer my original question now?
Remember folks, extra 'forcing', a radiant exitance, reduces net surface IR by the same.
The rise in temperature that follows is needed to create enough additional surface exitance + convection + evaporation to match incoming SW thermalisation. However, evaporation clamps surface IR increase to near zero so long as the extra latent heat can be removed. No significant surface exitance increase means there is near zero positive feedback, near zero ECS. The atmosphere self-controls.
The answer is I suspect in the conditional that follows the exposition of the model represented by Eq 3:
"If deltaQ is prescribed as the radiative forcing for a CO2 doubling, deltaTZDM is the value of EfCS
provided by the ZDM" p12
Other forcings exist.
ATTP,
If you read the paper, it's a pity you didn't get as far as Eqs 9 and 18. These are steady-state solutions for a fixed forcing - assumed to be 2xCO2 = 3.71 W/m2. Only the coefficients (flux gradients) are needed for the paper's calculations. You need me to pass you a spoon?
Paul_K,
Okay, I'll explain this more slowly (and, yes, I am being condescending). The result obtained in this paper is a consequence of concluding that non-Planck feedbacks are close to 0 and probably slightly negative. Given how this was assessed (Lindzen & Choi 2011) this applies to any form of warming, whether externally-forced or internally-driven. In fact, this suggests that any form of internally-driven warming should lead to cooling. Given this, how can we have warmed by ~1K after not yet doubling atmospheric CO2 and still have a positive planetary energy imbalance with a magnitude probably bigger than 0.5W/m^2? This is only really possible if non-Planck feedbacks are positive, which appears to be at odds with what this paper is suggesting. Do you get it now?
The last desperate redoubt of the scientivsts is the claim of ~0.5 W/m^2 'radiative imbalance'. This is an artefact from the 2009 recalibration of CERES data by reference to modelling. It's what they want the satellite data to prove, not reality.
Previously there was a 6.5 W/m^2 experimental radiative imbalance!
No, it's not. However, given that you appear to dispute the basic greenhouse effect, trying to expain this to you would probably be futile.
I don't doubt the repetitive forcing of pork pies, whether inside or outside a greenhouse.
Ultimately, the paper's calculated effective climate sensitivity is highly dependent on their estimate of the extra-tropical flux response (b2), which carries large uncertainty because of data ambiguity and lack of full satellite coverage at high latitudes. The paper shows results for two values: 3.5 and 2.0 W/m2/deg K. Support for this choice of range is given in Section 4.2 if anyone is interested, but in my view is quite weak. The lower value - which conforms rather more closely with mainstream thinking than the higher value yields an effective climate sensitivity of ca 1.5 deg K for a doubling of CO2, which gets fairly close to ZDM estimates using historical forcing, temperature and ocean heat data.
Indeed, hence my question. If we've warmed by ~1K, have yet to double atmospheric CO2, and still have a positive planetary energy imbalance, how can EfCS by ~1K?
ATTP:
"Indeed, hence my question. If we've warmed by ~1K, have yet to double atmospheric CO2, and still have a positive planetary energy imbalance, how can EfCS by ~1K?"
This would only trouble those who adhere to the canonical belief that there has been no other net significant long term forcing on global temperatures since 1850, or who believe that the more recent accelerated rise in global temperatures is not attributable in part to internal variability.
Jaime,
It doesn't change that this study is based on non-Planck feedbacks being 0, or negative. Essentially, you're suggesting that some other external factor has produced a forcing that means that the change in external forcing probably already exceeds that of doubling atmospheric CO2. This would require something producing a change of about 2W/m^2. What is it?
ATTP
If we go back to your original question, as framed with no respect to the paper, then the answer is obviously, we can't. There: do you feel better now?
Does that mean you're a misunderstood genius, Lindzen isn't, the paper's author is truly an Irish bog-trotter, and so forth (I'm sure we'll get to all these from you before too much longer)
I doubt that very much.
It would help if you framed your repost with a little more clarity. Doubling over what period, temperature rise over the same period . . .??
Capell,
I doubt it. I don't think I've ever said anything remotely comparable to this.
I very much doubt it will help. Here goes anyway, since pre-industrial times, we've warmed by almost 1K, we're about 60% towards doubling atmospheric CO2 (in terms of change in forcing) and we still have a positive planetary energy imbalace that probably exceeds 0.5W/m^2. How is this possible if non-Plancks are 0, or negative, as this paper is suggesting.
ATTP,
Condescend away my boy. I still can't take you seriously.
Oh dear, oh dear. You think that whether the feedback is above or below the Planck response determines the sign of net flux change in response to temperature? Please note that an increase in surface temperature whether internally driven or exogenously forced should lead to an increase in OLR i.e. the feedback is a cooling feedback. The only requirement for this is that the total signed feedback is negative, and it remains negative whether its magnitude is above or below the Planck response. Do we know that the signed feedback really is negative? Yes, the fact that we are still here tells us that.
The paper considered the same satellite and temperature data for the tropics as used in Lindzen and Choi as well as the data provided by Mauritzen and Stevens in order to estimate a range for the TOA flux gradient in the tropics. Do you have a problem with these data? Do you have a problem with the estimate of flux gradient? Please share your problem with us.
You seem to have a problem reconciling the results with your preconceptions about historical data. I have little difficulty. Well-founded point estimates of effective climate sensitivity based on the use of latest central estimates for forcing, net flux and temperature gain fall in the range 1.5 to 1.9 degrees, with some pressure towards the lower value if latest aerosol forcings are used. This however assumes that all of the temperature gain is attributable to exogenous radiative forcing. As I stated in my previous note, if the paper's lower estimate of extratropical fux gradient is used, the result is quite close to 1.5 deg K - not such a huge difference after all.
Ken, no it doesn't change criticisms of Bates' paper based upon the actual science therein but I'm just pointing out that the 'what else could it be' if Bates is right isn't necessarily a valid approach to critiquing the paper. We've been through this discussion quite a few times and it is by no means written in stone that long term solar forcing of climate can be dismissed out of hand, e.g. http://arxiv.org/PS_cache/arxiv/pdf/1102/1102.4763v1.pdf. Just one example among many which suggests that the IPCC have underestimated solar forcing
ATTP Try this: http://journals.ametsoc.org/doi/abs/10.1175/2008JCLI2637.1
'The 5-yr global mean CERES net flux from the standard CERES product is 6.5 W m−2, much larger than the best estimate of 0.85 W m−2 based on observed ocean heat content data and model simulations.'
They then adjusted the calibration to get different albedo and OLR estimates to fit. These differ markedly from the previous ERB-based data. I have no axe to grind except what I see from experiment, which proves the sign of the 2nd AIE is the reverse of what has been claimed, so it is the real AGW. I also accept the GHE, but most is from water vapour and the water cycle on our cloudy planet keeps any CO2 effect near zero. Take away the clouds and it would be very different.
We have an explanation of the post 1870 warming not needing CO2; it also explains end of ice age Milankovitch amplification and the Arctic melt freeze cycle.Sorry, but the basic failure of the 'forcing' argument will be revealed - it's down to GHG self-absorption physics and failure to understand that the bidirectional radiative energy transfer concept only applies to a vacuum.
Paul_K,
If you don't understand my question, you just need to ask me to clarify. I'll explain it one more time. Please concentrate this time. This paper suggests that the non-Planck feedbacks are 0, or negative. If we warm by ~1K, that would produce a Planck feedback of 3.2W/m^2. Since pre-industrial times, we increased anthropogenic forcings by about 2.3W/m^2. If non-planck feedbacks are 0, or negative, then if the system was in balance in pre-industrial times, we should have a negative planetary energy imbalance of around 0.9Wm^2 (i.e., losing energy). Instead we have a positive planetary energy imbalance that probably exceeds 0.5W/m^2. How is this possible?
Jaime,
I now we've been through this before and I find it odd that someone who clearly has a reasonable grasp of science seems to think that because we can't rule out things that we don't even know exist, that these are somehow things that we should take seriously. Of course we should consider alternatives and investigate if other factors could be playing a role. However, this is not an argument for assuming that these alternatives are likely, or possibly dominant.
attp.
Who cares? Apart from all of you who rely on the CAGW bandwagon to feed themselves? There's no evidence that the warming since the LIA has been anything other than beneficial, or that any warming still to come (we should be so lucky) will be otherwise. The planet's still here 4.5 billion years after its creation. And will be long after we are all gone. CAGW is a red herring. I suppose that were it just that it kept otherwise useless people off the streets, I wouldn't mind. But you drain my pockets and my tolerance. And 40,000 people died in Europe this winter from the cold.
Have a nice day.
And here's a reminder for Ken of just HOW low the climate crazies will stoop in support of the "cause"
https://wattsupwiththat.com/2016/05/13/breaking-cei-defeats-rico-20-ringleader-shukla-in-foia-lawsuit-emails-to-be-made-public/
Ken,
"I find it odd that someone who clearly has a reasonable grasp of science seems to think that because we can't rule out things that we don't even know exist, that these are somehow things that we should take seriously."
I find it even odder that someone who is a Prof of Physics seems to think that because we can't rule out things that we don't even know exist [large positive AGW feedbacks], that these are somehow things that we should take seriously.
Jaime,
I'm not quite sure what you mean, but if you think that I think that very large positive AGW feedbacks are somehow likely, then I don't. Does that clear that up? Probably not, but I'll state it for the record.
Jaime Jessop, you must remember that the "physicist" in question also teaches something called "Astrobiology".
lol
Michael Hart,
I've been avoiding commenting on this theme of yours, but I will add that you should consider that all you're really doing is illustrating your own ignorance, and that many "skeptics" seems to draw conclusions on the basis of very little evidence. Carry on, though, feel free to illustrate your ignorance to your heart's content; it is a free world.
NCC1701E
That turns out not to be the case. There is an indepentant check.
You can add up the annual energy input required to melt ice and warm surface, atmosphere and ocean as observed. That comes to 3*10^22J/year, equivalent to 0.6W/m^2.
ATTP
That was a rhetorical question; I even gave you the answer.
As soon as you frame that time period we can make time slices (e.g. 1915-45, 1960-1995), note the CO2 changes and temperature changes and immediately we see the ratios aren't the same. We all know this. So there must be other forcing some.
You claim the paper doesn't allow this . . .
OK: take it up with the authors. The rest of us can contemplate how small climate sensitivity seems.
Capella
Two problems.
As you consider shorter time periods the noise level due to other short term variables increases. This will decrease the correlation between CO2 change and temperature change over short periods.
The effect of increasing CO2 on temperature is not linear, it is natural logarithmic. Thus the 40% increase from 280ppm to 400ppm would be expected to produce 50% of the warming expected of a doubling from 280ppm to 560ppm. Earlier short time periods would be expected to show higher climate sensitivity than later periods.
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Come to think of it, if Bates' 1C sensitivity would mean that CO2 contributed 0.5C to the 1C warming since 1880. There is another 0.5C unaccounted for.
All the other known forcings are currently neutral or cooling. If Baates is correct, hat 1.5*10^22J/year is coming from an unknown source. If you want to convince the 97% that Bates is correct, you need to explain how all this energy is apparantly appearing from nowhere.
EM,
Thanks, I couldn't be bothered responding.
@Entropic Man: your argument only applies if the other part of Hansen et alia's calculations are correct. They assume ~1.6 W/m^2' aerosol forcing'. In reality we have had 'global brightening'** and part of that extra energy has melted ice and warmed the ocean surfaces.
**There is a second optical process missed by van der Hulst in 1967 and by Hansen in 1969. Climate Alchemy has been based on a false proposition of global dimming countering CO2-AGW.Sorry, but the observations made by G L Stephen's team, submitted in 2010 but delayed until very recently, in heavily disguised form, prove the case.
NCC1701E
The figure I used is for the rate of increaseof energy content of the system, 3*10^22J/year. This is calculated from the masses, temperature changes, specific and latent heats involved. No assumptions about where the energy is coming from are made.
If the energy is coming from a TOA imbalance it corresponds to a net incoming energy of 0.6W/M^2. This is independent of any other measurements and does not assume anything Hansen or albedo.
The sceptic side of the debate is in desperate need of a working alternative theory to AGW. Please explain your global brightening hypothesis more clearly, and show quantitatively that it explains the observed rate of energy uptake.
EM
I take it that was a reply to me?
"As you consider shorter time periods the noise level due to other short term variables increases. This will decrease the correlation between CO2 change and temperature change over short periods."
Do come on. That's such a minor point that it is merely pretentious and irritating.
"The effect of increasing CO2 on temperature is not linear, it is natural logarithmic. Thus the 40% increase from 280ppm to 400ppm would be expected to produce 50% of the warming expected of a doubling from 280ppm to 560ppm."
No shit Sherlock. I'll bet that absolutely none of us here knew that.
Say, perhaps you could compare my two trial periods, work out some ratios, and thus demonstrate that there's obviously a constant process at work throughout?
And while I'm wasting more of my time on those people who visit these pages and are physics challenged . . .
"You can add up the annual energy input required to melt ice and warm surface, atmosphere and ocean as observed. That comes to 3*10^22J/year, equivalent to 0.6W/m^2."
Come of it. Are you really telling me you can consider four components, each with at least two variables and come up with a value with an implied accuracy of one part in 7,000?
Come off it Entropic Man, the evidence of substantial reduction of apparent cloud area (~3%) during the fast warming 1980s and 1990s is in the ISCCP data. Actually it was probably reduction of cloud albedo picked up by satellite image analysis as a reduction of detected area.
3% reduction is about 2.15 W/m^2 extra surface insolation. For the past 20 years Earthshine project data have shown albedo is constant, probably explaining the 'hiatus'.
The most basic aspect of Science is that before any hypothesis can win, all other possibilities must be eliminated, and real cloud data probably trump modelled CO2 hypothesis claims. However, only improved observations will prove the cloud albedo hypothesis. The Jury is still out even though the carbonistas are rioting in the courtroom and threatening objective researchers with jail time under RICO etc., trying to stop the trial!
Entropic man says:
"There is an indepentant check.
You can add up the annual energy input required to melt ice and warm surface, atmosphere and ocean as observed. That comes to 3*10^22J/year, equivalent to 0.6W/m^2."
Yes, and the present imbalance is very clearly the result of an increase in solar input (ASR) and rather countered by an (overall still somewhat smaller) increase in earth's output (OLR). IOW, there is no AGW to be observed. It's all natural :-)
May 13, 2016 at 5:37 PM Phillip Bratby How much and over what period.
Bates does not confirm Lindzen and Choi, Bates assumes Lindzen and Choi, and therefore Bates (2016) fails on the same grounds
I will add to my above comment that the RICOteers at George Mason University have failed in their bid to avoid an FOIA request. The boot is on the other foot now. Next stop John Holdren!
https://wattsupwiththat.com/2016/05/13/breaking-cei-defeats-rico-20-ringleader-shukla-in-foia-lawsuit-emails-to-be-made-public/
NCC1701E
The Project Earthline data stops in 2007. Do you have anything for the nine years since then, particularly the warming years since 2010. If your hypothesis is correct, there should have been a decrease in cloud albedo over the last five years.
Kristian
What increase in solar input?
Solar cycle 23 peaked in 2000. Solar cycle 24 just peaked much less strongly.
A weakening Sun would not cause the record temperatures. We have just had two record years in 2014 and 2015, with 2016 currently even warmer.
Funding for climate scientists was high because of the assumed consequences, resulting from computer models programmed by climate scientists with a high ECS. Is a high ECS a problem of the minds of climate scientists?
What do models predict will happen to climate science funding, if ECS is dramatically reduced, perhaps to zero?
With ECS recalculated down, 99.97% of the population will be so much happier, and better off. The climate will continue not changing, at the same rate.
@EM: there is a new Project Earthshine article: http://onlinelibrary.wiley.com/doi/10.1002/2016GL068025/abstract
They grafted the data onto earlier ISCCP data in a previous publication.
Entropic man says:
"What increase in solar input?
Solar cycle 23 peaked in 2000. Solar cycle 24 just peaked much less strongly."
Do you know what ASR is? It's not equal to TSI. ASR is the solar radiation actually absorbed as heat by the earth system. ASR is what matters, not TSI. ASR increased significantly from 1985 to 1999 (ERBS) and has stayed pretty much flat since 2000 (CERES). All the while, global OLR at the ToA has gone up in step with global temps over the last 30-40 years (ERBS+CERES, ISCCP FD, HIRS).
No sign of any "enhanced GHE" anywhere, sorry ...
Kristian
Numbers please.
Siberia's deep mystery
Dmitry Streletskiy, an executive committee member for the Global Terrestrial Network of Permafrost, suspects that craters like this formed during the Holocene Climatic Optimum, a warm period 7,000 years ago. "It's likely we will see more of these," he says.
Leibman blames this destabilisation on local warming, rather than climate change. "For scientists, it is more important to look at something local, specifically the warm summer of 2012," she says. "Global warming is for the politicians."
http://www.wired.co.uk/magazine/archive/2015/02/start/siberia-deep-mystery
Ha ha ha ha ! My thoughts exactly.
NCC1701E
From the abstract.
How can this explain the warming?