Strong Negative Feedback from the Latest CERES Radiation Budget Measurements Over the Global Oceans
By Dr. Roy W. Spencer, Ph. D.
Arguably the single most important scientific issue – and unresolved question – in the global warming debate is climate sensitivity. Will increasing carbon dioxide cause warming that is so small that it can be safely ignored (low climate sensitivity)? Or will it cause a global warming Armageddon (high climate sensitivity)?
The answer depends upon the net radiative feedback: the rate at which the Earth loses extra radiant energy with warming. Climate sensitivity is mostly determined by changes in clouds and water vapor in response to the small, direct warming influence from (for instance) increasing carbon dioxide concentrations.
This can be estimated from global, satellite-based measurements of natural climate variations in (1) Earth’s radiation budget, and (2) tropospheric temperatures.
These estimates are mostly constrained by the availability of the first measurement: the best calibrated radiation budget data comes from the NASA CERES instruments, with data available for 9.5 years from the Terra satellite, and 7 years from the Aqua satellite. Both datasets now extend through September of 2009.
I’ve been slicing and dicing the data different ways, and here I will present 7 years of results for the global (60N to 60S) oceans from NASA’s Aqua satellite. The following plot shows 7 years of monthly variations in the Earth’s net radiation (reflected solar shortwave [SW] plus emitted infrared longwave [LW]) compared to similarly averaged tropospheric temperature from AMSU channel 5.
Simple linear regression yields a net feedback factor of 5.8 Watts per sq. meter per degree C. If this was the feedback operating with global warming, then it would amount to only 0.6 deg. C of human-caused warming by late in this century. (Use of sea surface temperatures instead of tropospheric temperatures yields a value of over 11).
Since we have already experienced 0.6 deg. C in the last 100 years, it would also mean that most of our current global warmth is natural, not anthropogenic.
But, as we show in our new paper (in press) in the Journal of Geophysical Research, these feedbacks can not be estimated through simple linear regression on satellite data, which will almost always result in an underestimate of the net feedback, and thus an overestimate of climate sensitivity.
Without going into the detailed justification, we have found that the most robust method for feedback estimation is to compute the month-to-month slopes (seen as the line segments in the above graph), and sort them from the largest 1-month temperature changes to the smallest (ignoring the distinction between warming and cooling).
The following plot shows, from left to right, the cumulative average line slope from the largest temperature changes to the smaller ones. This average is seen to be close to 10 for the largest month-to-month temperature changes, then settling to a value around 6 after averaging of many months together. (Note that the full period of record is not used: only monthly temperature changes greater than 0.03 deg. C were included. Also, it is mostly coincidence that the two methods give about the same value.)
A net feedback of 6 operating on the warming caused by a doubling of atmospheric CO2 late in this century would correspond to only about 0.5 deg. C of warming. This is well below the 3.0 deg. C best estimate of the IPCC, and even below the lower limit of 1.5 deg. C of warming that the IPCC claims to be 90% certain of.
How Does this Compare to the IPCC Climate Models?
In comparison, we find that none of the 17 IPCC climate models (those that have sufficient data to do the same calculations) exhibit this level of negative feedback when similar statistics are computed from output of either their 20th Century simulations, or their increasing-CO2 simulations. Those model-based values range from around 2 to a little over 4.
These results suggest that the sensitivity of the real climate system is less than that exhibited by ANY of the IPCC climate models. This will end up being a serious problem for global warming predictions. You see, while modelers claim that the models do a reasonably good job of reproducing the average behavior of the climate system, it isn’t the average behavior we are interested in. It is how the average behavior will CHANGE.
And the above results show that not one of the IPCC climate models behaves like the real climate system does when it comes to feedbacks during interannual climate variations…and feedbacks are what determine how serious manmade global warming will be.
RE: Jack Maloney: (May 7, 2010 at 2:34 pm) “A recent study has found that global warming has impacted the nature of symptoms experienced by obsessive compulsive disorder patients. Climate change related obsessions and/or compulsions were identified in 28% of patients presenting with obsessive compulsive disorder…”
Perhaps this is an example of what Charles Krauthammer might call ADS, or ‘AGW Derangement Syndrome.’
“Arguably the single most important scientific issue – and unresolved question – in the global warming debate is climate sensitivity. Will increasing carbon dioxide cause warming that is so small that it can be safely ignored (low climate sensitivity)? Or will it cause a global warming Armageddon (high climate sensitivity)?
Ermm.. We’ve forgotten a few things that have been well understood and established for decades..
Notably, that the Carboniferous Period had some 20x the CO2 we have today, not forgetting the Jurassic, with 10x the CO2 when delicate aragonite corals evolved.
Now, how could even doubling current CO2 cause a catastrophic runaway greenhouse or fabled tipping point when that’s never happened in the past even with comparatively gargantuan CO2 levels back then?
Not forgetting that CO2 change lags temperature change by some 800 years, and that nature outputs some 20x the CO2 we ever could (and it’ll continue to do so without us) and the more CO2 that’s available for nature to use, it does as proven in the past.
How is it we have fossils of corals and shellfish from the Jurassic when the oceans “should”, as climate catastrophists claim, be so acidic there’d be no chance of life?
Current PH of our oceans ranges from 7.9 to 8.3, which is alkaline. Notably, the oceans continually brush against alkaline rocks, so any chance of dangerous acidity has long been proven, thanks to the Jurassic, null and void.
Thanks to the very high CO2 levels of the Carboniferous and Jurassic, without ever a runaway greenhouse, has proven climate sensitivity a pointless ponderance as the question has already been answered, but alas, both ignored and forgotten in the race for the fad to become green..
Jeff Brown said:
“Many of the feedbacks that enhance warming of the planet are found in the polar regions…”
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Exactly! Thank you! From more open water in the arctic to the release of methane from melting bogs and changes in ocean circulation as a result of a warmer arctic, there are lots of potential positive feedback loops in the equation that have not been adeaquately factored in. From a geological perspective, there has been a “explosion” or burst of extra CO2 into the system over a the geologically short time of human industrialization, and the polar regions are the most sensitive to the effects of this burst.
James Sexton says:
May 7, 2010 at 9:05 pm
It’s funny how they continually bring up the arctic yet the ice has significantly grown the past 3 years?
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Uh, James, have you checked your ice charts lately? Arctic sea ice is currently below 2008 and 2009 levels for this date. I would have to say, just as a casual observer, this does not equal “significant growth”. And when looking at the more important metric, volume, well…nope, no growth there either:
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/BPIOMASIceVolumeAnomalyCurrent.png
I guess we who believe that AGWT just might be correct need to find some different charts to check so we can find this “significant growth”.
jorgekafkazar says:
May 7, 2010 at 5:54 pm
The fires stop generally when they run out of fuel or when the weather
changes.
I think these are what’s called negative feedbacks.
wildred says:
May 7, 2010 at 2:43 pm
jeff brown says:
May 7, 2010 at 3:28 pm
An interesting question, jeff and wildred. What Dr. Spencer shows above is 87 months of data. Whether this is enough data or not depends on the statistics of the relationship between the variables. Not having the data, I digitized it from his graph. In this case the relationships I find are:
Item, Value
Slope, 5.8
Error of Slope, 0.6
r^2, 0.54
Deg. Of Freedom, 86
F Statistic, 101.5
T Statistic, 10.1
Slope Signif., two tailed T-test, p = 3E-16
r^2 Signif., F-Test, p = 2E-23
In other words, both the slope of the relationship and the r^2 value are extremely significant, as the p-value is vanishingly small. So the answer in this case is yes, 87 months of data is more than enough to determine the relationship reliably.
As to why people don’t give it “the same critical examination given to papers that suggest humans are affecting the climate”, there’s a couple of issues here.
First, curiously, people trust that Dr. Spencer has tested the significance of his results … and in this case at least, people are right. You’ll forgive me if I don’t extend the same assumption to most AGW supporting scientists …
Second, I also assume that if his data is not significant, some AGW supporter will point that out in fairly short order. You analyze the papers you find doubtful, I analyze the papers I find doubtful, there’s not enough time for me to analyze every paper I read. In this case, I’ve done the work for you guys … in future, rather than simply tossing out uninformed speculations that Dr. Spencer has not done his homework, I invite you to do the analysis. It took me a total of about 45 minutes including digitizing the data …
davidc says:
May 7, 2010 at 7:27 pm
Change in flux F and in temperature T is [F(n) – F(n-1)] and [T(n) – T(n-1)] where n is time. The blue lines connect the dataset in temporal order. The slope of those lines is the slope of the relationship from one instant of time to the next.
Dr. Spencer introduced the concept a while back that looking at the average slope of those lines is a more meaningful measure of the actual relationship between the variables than is the overall trend line. I think his idea has merit. In this case the two are quite similar (6 vs. 5.8).
There are two questions I have about this work. Firstly, is the measurement accurate when applied to the long term range of climate states? We know that the past 10 years have shown short-term conditions which seem to differ from the previous 20-30 years. I am unsure if a significant volcanic event would be expected to produce results in this data set with the same range (at a different absolute temperature) or not.
Second, since the measurement is in effect an instantaneous observation rather than an integration of discrete weather events, it seems reasonable to construct a climate model which reflects this behavior. Can other model parameters give closure in the short term, and long term stability, or is there an imbalance in the model which can’t be justified using what we understand today to be plausable forcings? How about if we run the new model backwards to re-construct temperature for the past 150 years…
@Roy Spencer says:
May 7, 2010 at 3:59 pm
“If I give more of the technical details to support my conclusions, people complain they don’t understand. If I don’t include the details to keep it simple, they complain that I’m not justifying my claims.”
Thank You Mr. Spencer! – your simple summery for Tax Payer (..and Fly Fisher) is highly Appreciated!
@Brent Hargreaves says:
May 7, 2010 at 4:50 pm
“Can the AGW hypothesis be refuted by demonstrating that the climate is governed by negative feedback”
Don’t think so, consensus is that the AGW hypothesis is governed by positive funding feedback
Measurement trumps models and Dr Roy Sinclair has come up trumps!
What Spencer has done here is to essentially take the first derivative of the data at a number of discrete points. I like that approach.
jeff brown says:
May 7, 2010 at 3:28 pm
I agree with Wildred…only 7 years of data to make these sweeping statements? Interesting how some on this post easily buy into Dr. Spencer’s conclusions w/o the same critical examination given to papers that suggest humans are affecting the climate. Seems very biased.
Willis has given one way to respond to this. Here’s another.
The amount or volume of data used to form a hypothesis is irrelevant to its scientific credibility, per se. All that matters is that it be a testable hypothesis. Roy’s certainly meets that criteria. The amount of data, or here, the length, may influence the “robustness” (there has got to be a valid use of the word somewhere) of the hypothesis, but it is determinative per se of whether it is a useful hypothesis. Maybe the sensitivity that Roy has determined is sensitive to climatic conditions, and with other climatic conditions the sensitivity changes. Time will test the “robustness” of the hypothesis.
How much data did Einstein have to base the Special Theory of Relativity on? While he was seeking to explain a variety of prior experimental results, his hypothesis had consequences that had not yet been observed. Observation isn’t even a necessary condition to formulating a scientific hypothesis! It seems to me that Roy is doing excellent science here, by deductively framing alternative theories, i.e. considering what might be the consequences of reversing traditional thinking about cause and effect. That is all it takes to formulate an hypothesis. If we only have seven years of suitable observed data to test his hypothesis, that is infinitely more data than what Einstein had at the time to test the consequences of his hypothesis.
So the amount of data that Roy has used from the past in formulating his hypothesis is entirely irrelevant to its testability. Whether it will hold up in the future is what will determine its scientific value.
I left out a crucial “not:” but it is not determinative per se of whether it is a useful hypothesis.
I applaud Dr. Spencer’s work. I read his first book and thoroughly enjoyed it.
That said, and in my humble opinion, what is really missing from climate science can be said in two words “CLASSICAL EXPERIMENTATION”. I miss the days when someone would put forth a hypothesis, then carefully design a set of real world experiments to narrow down the variables and show meaningful indisputable results. That has all gone out the window in favor of modeling and probabilistic number crunching, with limited and often faulty sets of real world data or worse (proxies), then extrapolating conclusions from these probability limited and therefore open-ended mathematical constructs. I’m from the “show me” generation, and to me that has always meant simple, real world experimental results……
Best,
Jose
Dr Spencer, I just ran a search through Google news for mentions of your name in relation to your groundbreaking work presented in recent published papers and in your new book, and remarkably,I can find no mention of the work in the mainstream press.
Climate modeler Prof Andy Pitman has stated elsewhere: “There is a Nobel Prize awaiting Carter [MH. that’s Prof Bob Carter], or other skeptics, for that paper that buries global warming. There is world-wide acclaim, there is that Chair at Cambridge and the thanks of governments the world over. My question is why none of them have published this evidence – but of course the question is rhetorical … because while every decent climate scientist looks for flaws in the data, the models and the theory we have not been able to find any …” (see http://littleskepticpress.blogspot.com/2009/03/geologists-were-right-conversations.html for the full “conversation”)
I guess it will be news once they hand you the Nobel. Care to comment on the absence of media interest?
The issue of reduced radiation in the CO2 bands has been brought up yet again. In my opinion this is yet more proof of NEGATIVE feedback.
If the feedback was positive one should see no change or an increase. That is, the Earth would warm and, although some radiation is intercepted, the increase in heat would increase the radiation from the Earth. The net should be equal or increased radiation overall.
The overall reduction implies that CO2 is absorbing more photons but that is not leading to any warming, hence there must be some negative feedbacks in place.
@ur momisugly R. Gates says:
Uhmm, ok, if you want to put a sine wave on a linear graph, go here. http://nsidc.org/data/seaice_index/images/n_plot_hires.png . I suppose we can argue the veracity of our sources, but either one, contradicts the positive feedback, polar region sensitivity blathering. Even the graph you offered shows a significant period of time, (1997-2003) the ice was above the linear average. How does one account for that if the arctic is so sensitive? We didn’t stop emitting CO2 or methane during that time period. Did the arctic is call a time out? Go here for a better representation http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png . I don’t understand why otherwise intelligent people refuse to believe there could be something else driving our climate other than GHG. Why defend a premise that has been shown wrong on almost every level? Could you imagine how much we can achieve once the warmistas go away? Sadly, the anti-industrialists and Malthusians will find another cause, but many warmists could and would live otherwise productive and meaningful lives and cease to waste the time of sensible people with their alarmist musings.
A very interesting contribution. I look forward to seeing the full paper when it comes out.
One comment: As Klotzbach et al (2009) showed, there remains substantial discrepancy between the satellite measured lower troposphere temperature trend and the surface temperature trend, especially at high northern latitudes over land, and especially in winter. It is pretty well known that there has be a substantial divergence between ocean and land (surface instrument) temperature trends in the last 30+ years, with average land temperatures, especially in the far north, rising much faster than average ocean surface temperatures, which seems consistent with Klotzback et al.
So one needs to be a little cautious I think. Roy’s results sure look solid enough for the lower tropospheric temperatures, but the Klotzback et al results suggest that measured surface temperature may turn out to be somewhat more sensitive to CO2 than the lower troposphere. I don’t know how much more sensitive, but perhaps applying an “adjustment” to Roy’s calculated sensitivity, based on the surface/troposphere discrepancy Klotzback et al described, would yield a better estimate of the net sensitivity of surface temperatures to increased CO2.
Didn’t have time to read every post, only about half and am perplexed at the hard headedness in most. What about, “opening up the debate”, “keeping people abreast of the latest information”, and, “keeping it understandable” for laypeople don’t many of you get? For crying out loud! He posts an abbreviated update from a technical paper he’s working on and, again many of you jump right into the “settled science” camp. what gives? Don’t bother posting if you can’t keep a “stable” open mind or maintain an “equalibrium”.
Good science starts with good observation, that is what this blog is about, that is what this new information is about, that is all. The data is delivered on the same time scales, from the same coordinate as the IPCC claims so it is a justified comparison. One that contributes to opening the debate to the validity of the many claims made by the AGW proponents and the models they depend on. Get it? 8>)
DR says:
May 7, 2010 at 4:53 pm
Next thing you know, Nick Stokes will be convincing us the oceans really do warm from the bottom up 🙂
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Perhaps Nick has found the missing heat, aka, the the earth’s induction heater ;).
I like that the hypothesis is formed from just seven years. A model made by finding relationships in the entire historical record can’t be tested by seeing whether it can recreate the same past climate trends used to create it. One based on seven years, while facially less robust, has the benefit of being testable with past data. If the trend he identifies from the seven years fits the past 100, we’d have a pretty good idea that he’s right.
Steve Fitzpatrick says: It is pretty well known that there has be a substantial divergence between ocean and land (surface instrument) temperature trends in the last 30+ years, with average land temperatures, especially in the far north, rising much faster than average ocean surface temperatures, which seems consistent with Klotzback et al.
Far north temperatures are very volatile, they were in the same range as now in the thirties and fourties. In addition, temperatures in winter are extremely sensitive to siting issues, and unfortunately too many of the stations still in use are now located at airports.
How do we get ice ages if the climate sensitivity is as low as Dr. Spencer proposes?
The Milankovitch cycles don’t significantly change the amount of energy reaching the earth- they just change the seasonal distribution.
Nobody has come up with a way to go into- or come out of- an ice age without significant positive feedbacks, and a much higher climate sensitivity than Dr. Spencer estimates.
Ref – AGW-Skeptic99 says:
May 7, 2010 at 11:01 pm
“I wonder if anyone cares to comment on when a boundary condition will be reached? Week after week we have additional evidence that the ‘CO2 will end civilization as we know it’ campaign is doomed….What does it take to make the tide start going the other way. As of now most of the people controlling money and politics treat skeptics like lepers. They don’t want to converse with us or be seen in our company.”
_________________________
Inertia is difficult to overcome.
The AGW reaction has been completed. The appearence of continued reaction is actually smoke.
The smoke and residue will remain in place until removed by another reaction.
Mental, and political, ‘reactions’ are very slow and take a great deal of time in the absence of a catalyst.
Words are not catalysts.
Money is a catalyst in human reactions.
For people to change they have to get off their butt and do something.