“…ERBE data appear to demonstrate a climate sensitivity of about 0.5°C which is easily distinguished from sensitivities given by models.”
On the determination of climate feedbacks from ERBE data
Richard S. Lindzen and Yong-Sang Choi
Revised on July 14, 2009 for publication to Geophysical Research Letters
Abstract
Climate feedbacks are estimated from fluctuations in the outgoing radiation budget from the latest version of Earth Radiation Budget Experiment (ERBE) nonscanner data. It appears, for the entire tropics, the observed outgoing radiation fluxes increase with the increase in sea surface temperatures (SSTs). The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity. This is the opposite of the behavior of 11 atmospheric models forced by the same SSTs. Therefore, the models display much higher climate sensitivity than is inferred from ERBE, though it is difficult to pin down such high sensitivities with any precision. Results also show, the feedback in ERBE is mostly from shortwave radiation while the feedback in the models is mostly from longwave radiation. Although such a test does not distinguish the mechanisms, this is important since the inconsistency of climate feedbacks constitutes a very fundamental problem in climate prediction.
Introduction
The purpose of the present note is to inquire whether observations of the earth’s radiation imbalance can be used to infer feedbacks and climate sensitivity. Such an approach has, as we will see, some difficulties, but it appears that they can be overcome. This is important since most current estimates of climate sensitivity are based on global climate model (GCM) results, and these obviously need observational testing.
To see what one particular difficulty is, consider the following conceptual situation:
We instantaneously double CO2. This will cause the characteristic emission level to rise to a colder level with an associated diminution of outgoing longwave radiation (OLR). The resulting radiative imbalance is what is generally referred to as radiative forcing. However, the resulting warming will eventually eliminate the radiative imbalance as the system approaches equilibrium. The actual amount of warming associated with
equilibration as well as the response time will depend on the climate feedbacks in the system. These feedbacks arise from the dependence of radiatively important substances like water vapor (which is a powerful greenhouse gas) and clouds (which are important for both infrared and visible radiation) on the temperature. If the feedbacks are positive, then both the equilibrium warming and the response time will increase; if they are negative, both will decrease. Simple calculations as well as GCM results suggest response times on the order of decades for positive feedbacks and years or less for negative feedbacks [Lindzen and Giannitsis, 1998, and references therein].
The main point of this example is to illustrate that the climate system tends to eliminate radiative imbalances with characteristic response times.
Now, in 2002–2004 several papers noted that there was interdecadal change in the top-of-atmosphere (TOA) radiative balance associated with a warming between the 1980’s and 1990’s [Chen et al., 2002; Wang et al., 2002; Wielicki et al., 2002a, b; Cess and Udelhofen, 2003; Hatzidimitriou et al., 2004; Lin et al., 2004]. Chou and Lindzen [2005] inferred from the interdecadal changes in OLR and temperature that there was a strong negative feedback. However, this result was internally inconsistent since the
persistence of the imbalance over a decade implied a positive feedback. A subsequent correction to the satellite data eliminated much of the decadal variation in the radiative balance [Wong et al., 2006].
However, it also made clear that one could not readily use decadal variability in surface temperature to infer feedbacks from ERBE data. Rather one needs to look at temperature variations that are long compared to the time scales associated with the feedback processes, but short compared to the response time over which the system equilibrates. This is also important so as to unambiguously observe changes in the radiative budget that are responses to fluctuations in SST as opposed to changes in SST resulting from changes in the radiative budget; the latter will occur on the response time of the system. The primary feedbacks involving water vapor and clouds occur on time scales of days [Lindzen et al., 2001; Rodwell and Palmer, 2007], while response times for relatively strong negative feedbacks remain on the order of a year [Lindzen and Giannitsis, 1998, and references therein]. That said, it is evident that, because the system attempts to restore equilibrium, there will be a tendency to underestimate negative feedbacks relative to positive feedbacks that are associated with longer response times.
Concluding Remarks
In Figure 3, we show 3 panels. We see that ERBE and model results differ
substantially. In panels a and b, we evaluate Equation (3) using ΔFlux for only OLR and only SWR. The curves are for the condition assuming no SW feedback and assuming no LW feedback in panels a and b, respectively. In panel a, model results fall on the curve given by Equation (3), because the model average of SW feedbacks is almost zero. In panel b, models with smaller LW feedbacks are closer to the curve for no LW feedback; the model results would lie on the curve assuming positive LW feedback. When in panel c we consider the total flux (i.e., LW + SW), model results do lie on the theoretically expected curve.
Looking at Figure 3, we note several important features:
1) The models display much higher climate sensitivity than is inferred from ERBE.
2) The (negative) feedback in ERBE is mostly from SW while the (positive) feedback in
the models is mostly from OLR.
3) The theoretical relation between ΔF/ΔT and sensitivity is very flat for sensitivities
greater than 2°C. Thus, the data does not readily pin down such sensitivities. This was
the basis for the assertion by Roe and Baker [2007] that determination of climate
sensitivity was almost impossible [Allen and Frame, 2007]. However, this assertion
assumes a large positive feedback.
Indeed, Fig. 3c suggests that models should have a range of sensitivities extending from about 1.5°C to infinite sensitivity (rather than 5°C as commonly asserted), given the presence of spurious positive feedback. However, response time increases with increasing sensitivity [Lindzen and Giannitsis,1998], and models were probably not run sufficiently long to realize their full sensitivity. For sensitivities less than 2°C, the data readily distinguish different sensitivities, and ERBE data appear to demonstrate a climate sensitivity of about 0.5°C which is easily distinguished from sensitivities given by models.
Note that while TOA flux data from ERBE are sufficient to determine feedback factors, this data do not specifically identify mechanisms. Thus, the small OLR feedback from ERBE might represent the absence of any OLR feedback; it might also result from the cancellation of a possible positive water vapor feedback due to increased water vapor
in the upper troposphere [Soden et al., 2005] and a possible negative iris cloud feedback involving reduced upper level cirrus clouds [Lindzen et al., 2001]. With respect to SW feedbacks, it is currently claimed that model SW feedbacks are largely associated with the behavior of low level clouds [Bony et al., 2006, and references therein]. Whether this is the case in nature cannot be determined from ERBE TOA observations.
However,more recent data from CALIOP do offer height resolution, and we are currently studying such data to resolve the issue of what, in fact, is determining SW feedbacks. Finally, it should be noted that our analysis has only considered the tropics. Following Lindzen et al. [2001], allowing for sharing this tropical feedback with neutral higher latitudes could reduce the negative feedback factor by about a factor of two. This would lead to an
equilibrium sensitivity that is 2/3 rather than 1/2 of the non-feedback value. This, of course, is still a small sensitivity.
see the full paper here (PDF)
h/t to Leif Svalgaard
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I am back to the same comment I made in another thread. Are hypothesized drivers such as solar or CO2 additive to natural variability or simply buried by it? I think the coupling of endogenous nature and exogenous solar or pollution, if there is one, that would explain an additive nature, has not been proposed that I know of. The IPCC sponsored models ignore or have not mechanized natural variability so they fudge it. If it is not additive and nature trumps, we can ignore both solar and CO2. If it is additive, does nature undo the warming and reset the clock? If this is true, we can still ignore solar and/or CO2. If it is additive and permanent (as in the tipping point case), we should try to reverse, prepare and adjust. What is important here is to flesh out the mechanism that can be substantiated with observed phenomena, or else we buy a pig in a poke. The current IPCC modeled CO2-temp scenarios do not match observations. Somebody needs to go back to the drawing board.
The climate models are still producing the same numbers they did 30 years ago. All of the improvements, additional data and greater understanding hasn’t changed the results much at all. If you ask any of the main modelers if any new information will change the numbers significantly, they all answer “certainly not lower, if anything the sensitivity will go higher”.
So, we don’t need any further modeling or newer, faster climate models. It won’t make any difference, we’ve reached equilbrium/the end with respect to theoritical modeling.
What we need now is actual measurements.
This paper provides measurements of the basic system itself and the basic GHG sensitivity itself so now we are moving forward again.
It appears that the editors of these journal (Journal of Geophysical Research and Geophysical Research Letters) have finallly shed their bias for papers advocating AGW.
“”” Paul Linsay (10:52:10) :
The blackbody temperature of the equatorial oceans at high noon is approximately 181F=83C (flux = 1360 w/m^2, emissivity = 0.67). Add in the radiative effect of water vapor and they should be almost boiling. Of course the “feedback” is negative. “””
You want to specify where abouts in the equatorial oceans, at high noon the water temperature gets to 181 F or 83 C. You realize that 1360 W/m^2 is just 6 below the extra atmospheric TSI level. And just how did the emissivity of the oceans get down to as low as 0.67; it should be more like 0.97, certainly for the LW radiant emissions.
You need to go back to the drawing board, and do some recalculations.
I would like to share the following extracts that show in order:
[1] ‘Interpretation’of observation.
[2] Observation
[3] Puzzlement where observation is not expected.
All are related to positive feedback or lack of.
[1] http://news.bbc.co.uk/1/low/sci/tech/7786910.stm
17 December 2008 Autumn return
Theory predicts that as ice is lost in the Arctic, more of the ocean’s surface will be exposed to solar radiation and will warm up. When the autumn comes and the Sun goes down on the Arctic, that warmth should be released back into the atmosphere, delaying the fall in air temperatures.Ultimately, this feedback process should result in Arctic temperatures rising faster than the global mean. Dr Stroeve and colleagues have now analysed Arctic autumn (September, October, November) air temperatures for the period 2004-2008 and compared them to the long term average (1979 to 2008). The results, they believe, are evidence of the predicted amplification effect.
“You see this large warming over the Arctic ocean of around 3C in these last four years compared to the long-term mean,” explained Dr Stroeve. “You see some smaller areas where you have temperature warming of maybe 5C; and this warming is directly located over those areas where we’ve lost all the ice.”
NSIDC – November 10, 2008
An expected paradox: Autumn warmth and ice growth
As is normal for this time of year, ice extent increased rapidly through most of October. However, this year, the increase was particularly fast, which contributed to above-average air temperatures near the surface.Figure 3. In this image, near-surface air temperatures show strong warming near the surface in the Beaufort sea region, an area with substantial open water at the end of the melt season. The anomalously high temperatures extend well up into the atmosphere, showing that the ocean is transferring heat to the atmosphere as ice forms.
[2] NOAA – Arctic summer time the puzzling summer of 2003 Norbert Untersteiner
Observations from the North Pole in summer 2002
The recently recorded data from automatic buoys and web cams represent a large, and very inexpensively obtained, increment of information about summer conditions in the central Arctic.
Fig. 2 (no image) Late July 2002 at the NPEO drifting station. The onset of surface melting is exceptionally late.
The onset of melting usually occurs in early June, when the temperature reaches 0°C and the surface layer turns into a constant-temperature ice bath. In 2002, the temperature record shows an abrupt warming to about 0°C, on 24 May, suggesting an early arrival of the melt season. The warming event coincides with about a week of low short-wave (250 Wm-2) and high long-wave (300 Wm-2) down-welling radiation, which are typical of low overcast conditions. The web cam pictures of that period confirm the overcast. Both radiation and temperature values remained in the normal range for the rest of the summer, and freeze-up occurred as usual in the last week of August. Based on the early warming event in May, one may have expected an early onset of surface melting. Contrary to that expectation, the web cams show that it was not until late July 2002 when the snow cover took on a soggy appearance and isolated melt ponds appeared on the surface (Fig.2).
For the rest of the summer, the web cam pictures show only insignificant melt pond coverage until the deposition of new snow in late August. The pictures clearly show that snow from the preceding winter survived the entire summer, and we must assume that there was no, or very little, ice ablation at the surface.
I am a little concerned that the last time that Dr Lindzen referenced the ERBE data on a WuWT guest post, there were a number of questions raised about the validity of the data. These questions were not answered fully apart from a very brief reference to the lack of credibility of some of the adjustments. On scanning the full paper here, I still cannot find a rebuttal of the proposed data adjustments which would have the effect of reducing the OLR and hence the validity of the conclusions of the paper.
Woaa boy !
from solar cycle 24:
“A small new sunspot is trying to form in the middle of the solar disk. It belongs to Cycle 23. Just when you think that Cycle is over, another sunspot appears”. D Archibald = 100% correct
As a follow-up to my previous post, I should say that I am a confirmed sceptic, but I believe that for the best science to win, the sceptics need to follow some traditional tests of scientific integrity, including a willingness to challenge one’s own views. We do not win this argument by trying to match the overbearance of our opponents.
There is a small but steady flow of peer reviewed analysis of real data that is being produced by real scientists like Lindzen and Spencer. These guys are not making an assumption that the numerous GCM’s truely reflect the real earth climate system. Its about time for some of the climate modellers to closely examine this work and build the results into the models. Then they might actually start to get useful results.
COMMENTS IN CAPS
Gary Crough (13:20:18) :
Richard S. Lindzen has always been skeptical of a positive global temperature feedback loop … as have scientists outside the AGW community. 3rd parties wonder why we would not get stuck in an ice age (or heat age) if feedback was positive. TEND TO AGREE – THE FACT THAT WE ARE HERE HAVING THIS CONVERSATION SUGGESTS THAT FEEDBACKS ARE NEGATIVE.
Will this paper lead to revision of GW models? My guess: No.
My understanding is (1) the vast majority of CO2 is stored in the ocean YES
and (2) CO2 has increased at a very consistent pace since the Mauna-Loa measurements started (pre-1960) THERE HAS BEEN SOME UPWARD SLOPE IN CO2 AT THE SAME TIME AS INCREASED INDUSTRIAL ACTIVITY. In fact, the increases don’t seem to track industrial activity (reduced increases in a recession). CORRECT – ATMOSPHERIC CO2 DOES NOT TRACK PERTERBATIONS IN INDUSTRIAL ACTIVITY DUE TO MAJOR RECESSIONS, THE OIL CRISIS, ETC. Are these assumptions correct? If so, has any consideration been given to the possibility that current CO2 increases are mostly a reflection of the ocean/atmosphere re-establishing an equilibrium? (Ocean releasing CO2 very slowly because it is warmer?) PPOSSIBLE – THE ONLY SIGNAL I’VE BEEN ABLE TO DETECT IN THE CO2 PROFILE IS A LAG OF 9 MONTHS BEHIND GLOBAL AVERAGE TEMPERATURE. dCO2/dt TRACKS TEMPERATURE WITH LITTLE OR NO LAG, AND TEMPERATURE LAGS CO2 (THE INTEGRAL OF dCO2/dt) BY ~ 9 MONTHS.
SEE
http://icecap.us/index.php/go/joes-blog/carbon_dioxide_in_not_the_primary_cause_of_global_warming_the_future_can_no/
The thing I’m concerned about is that Lindzen has to write:
“and these obviously need observational testing.”
Now of course it should be obvious, because it is a fundamental component of the demarcation of science. To me however whenever someone writes something like that to me it sounds like a polite way of saying ‘some people seem to be ignoring this obvious statement’.
CORRECTION – PLEASE DELETE/DISREGARD MY PREVIOUS VERSION
COMMENTS IN CAPS
Gary Crough (13:20:18) :
Richard S. Lindzen has always been skeptical of a positive global temperature feedback loop … as have scientists outside the AGW community. 3rd parties wonder why we would not get stuck in an ice age (or heat age) if feedback was positive. TEND TO AGREE – THE FACT THAT WE ARE HERE HAVING THIS CONVERSATION SUGGESTS THAT FEEDBACKS ARE NEGATIVE.
Will this paper lead to revision of GW models? My guess: No.
My understanding is (1) the vast majority of CO2 is stored in the ocean YES
and (2) CO2 has increased at a very consistent pace since the Mauna-Loa measurements started (pre-1960) THERE HAS BEEN SOME UPWARD SLOPE IN CO2 AT THE SAME TIME AS INCREASED INDUSTRIAL ACTIVITY. In fact, the increases don’t seem to track industrial activity (reduced increases in a recession). CORRECT – ATMOSPHERIC CO2 DOES NOT TRACK PERTERBATIONS IN INDUSTRIAL ACTIVITY DUE TO MAJOR RECESSIONS, THE OIL CRISIS, ETC. Are these assumptions correct? If so, has any consideration been given to the possibility that current CO2 increases are mostly a reflection of the ocean/atmosphere re-establishing an equilibrium? (Ocean releasing CO2 very slowly because it is warmer?) PPOSSIBLE – THE ONLY SIGNAL I’VE BEEN ABLE TO DETECT IN THE CO2 PROFILE IS A LAG OF 9 MONTHS BEHIND GLOBAL AVERAGE TEMPERATURE.
dCO2/dt TRACKS TEMPERATURE WITH LITTLE OR NO LAG, AND CO2 (THE INTEGRAL OF dCO2/dt) LAGS TEMPERATURE BY ~ 9 MONTHS.
SEE
http://icecap.us/index.php/go/joes-blog/carbon_dioxide_in_not_the_primary_cause_of_global_warming_the_future_can_no/
Meanwhile, “Science” just published an article basically claim’n that clouds thin with increased warming.
http://www.sciencemag.org/cgi/content/abstract/325/5939/460
“It does indicate that perhaps we should be giving serious consideration to the high end, the high range of future warming.”
http://www.aaas.org/news/releases/2009/0723sp_clouds.shtml
I have some questions that I hope might be interesting enough to answer. From the NSIDC observation (posted previously) the air above Arctic ocean that is beginning to freeze will be warmed by the transfer of heat out of the water. In this case the air temperature will be warmer than the Ocean as it freezes but it does not re-warm (feedback) that Ocean and prevent freezing.
My question is, if the surface temperature is 20C and radiation from the surface warms a parcel of air at altitude from say 10C to 12C, how does that warm the surface?
Also how does the air choose which method to transfer heat? Why is it always with radiation? If a parcel of air warms I thought it would expand and then rise up in relation to the surrounding air – first.
RE: Stephen Skinner (14:45:34) :
**“You see this large warming over the Arctic ocean of around 3C in these last four years compared to the long-term mean,” explained Dr Stroeve. “You see some smaller areas where you have temperature warming of maybe 5C; and this warming is directly located over those areas where we’ve lost all the ice.” **
Can someone tell me where this warming was and how it was measured?
For example, Resolute did not change anywhere near 3 degrees.
Mac is right, this paper is quite a read.
http://www.agu.org/pubs/crossref/2009/2008JD011637.shtml
Gerald Machnee (15:23:09) :
Can someone tell me where this warming was and how it was measured?
Unfortunately I cannot find the link to the NSIDC article directly below that (should have been labelled [2]). This showed temperatures around this figure. My point was, NSIDC noted the high temperatures was normal when ice is forming. Dr Stroeve appears to be implying that these same high temperatures around the same time of year are odd.
Paul (14:59:54) : It is way past time the warmers started doing some real science without prodding from skeptics. Certainly all climate science should be examined and re-examined, confirmed or refuted by others, and refined or rejected. The warmers don’t seem to try to come up with ideas or alternative explanations that might prove them wrong. There is no examination of one’s own work. This sort of self-criticism and soul searching is the mark of a good scientist. Instead, hostility and belittlement is directed at anyone who dares suggest any alternative explanation for climate phenomena. I would say it’s anti-science or perhaps even pathological science.
Warning. Whacky hypothesizing.
1) Even 0.5 degrees of permanent warming is not trivial. Look at the UAH satellite temperature record and add 0.5 to it.
2) The real sensitivity of the climate system may take centuries to manifest. The periodicity of the ice ages started when the isthmus of Panama was raised 3 million years ago. The changed continental configuration caused the Earths climate to go from a low sensitivity to a high sensitivity mode. Because this sensitivity occurs via ocean currents, and ocean currents take hundreds of years to modify their courses, then the real sensitivity may take a long time to demonstrate its true value. Perhaps this ice age sensitivity is only to short wave radiation and not long wave radiation, but I don’t understand how.
3) This long-term sensitivity suggests that there is no short-term non-oceanic sensitivity via the water vapor feedback, otherwise this water vapor feedback would have masked out the oceanic sensitivity, and there would have been permanent periodic ice ages irrespective of the continent positions. A low short-term sensitivity measurement is consistent with the fact of the onset of ice age periodicity.
So it would be good to have a theory that accounts for everything.
Well it is already known the Earth’s atmosphere doesn’t work like a commercial greenhouse.
1). Glass in the sun holds in heat a heck of a lot better than anything CO2 could do.
2). Convection to transport heat out of the greenhouse is not possible because it’s encased in glass.
And also, because the Earth’s atmosphere gets thinner the higher you go, the highest GHG concentrations would be at your feet, the gases are not forming a wall high in the atmosphere to bounce heat back down like some science textbooks show.
“”” Stephen Skinner (15:19:19) :
I have some questions that I hope might be interesting enough to answer. From the NSIDC observation (posted previously) the air above Arctic ocean that is beginning to freeze will be warmed by the transfer of heat out of the water. In this case the air temperature will be warmer than the Ocean as it freezes but it does not re-warm (feedback) that Ocean and prevent freezing. “””
Where on earth did you come up with the idea that when the ocean freezes, that the atmosphere above it will warm up. It’s a reasonably safe bet, that the ocean will not freeze unless the air above it is much colder than the sea water.
For the sea water to cool down around -2.5 deg C, where is can start to freeze, it can only lose energy by either radiation, or by conduction to a cooler atmosphere. If the air is warmer than the water, the “heat” energy would be going into the ocean to stop it from freezing.
Does the air in your refrigerator heat up when you make ice cubes ? I don’t think so !
As I said before, what worst than being cold and hungry?
Being WET, cold and hungry. How the clouds may move out and the sun may warm your face, but you are still WET, cold and hungry.
Stephen, do you know where the Arctic currents are and whether they be hot or cold? Here is a website for your education. The warmth is where the warm currents are and always have been. The cold is where the cold currents are and always have been. Some of these currents circulate within the Arctic, some come from outside of it. You should spend some time understanding these currents and their oscillations before you simply accept someone else’s view of a “warming” ocean in the Arctic. It would also be wise to follow the Northern Hemisphere jet stream on a daily basis. This will explain both ice behavior in situ and ice melt. Right now, ice is not melting, it is being compacted into a smaller area, thanks to a fairly strong jet stream shoving ice into bigger and bigger piles on all sides. The charts that show sudden catastrophic melt are misrepresenting the situation big time.
http://www.aquatic.uoguelph.ca/oceans/ArticOceanWeb/Currents/frontpagecur.htm
http://squall.sfsu.edu/crws/jetstream.html
“It appears, for the entire tropics, the observed outgoing radiation fluxes increase with the increase in sea surface temperatures (SSTs). The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity.”
How long until this makes it into text books ?
VG (14:57:05) : D Archibald = 100% correct
Maybe we’ll get an guest post update from Archibald soon.