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.
Isn’t it interesting the “proof” of AGW the IPCC AR4 relied on was based on ten years of OHC data (of which is questionable prior to 2003; the step change) thereby “validating” Hansen’s climate model, yet 7 years of observational data disagreeing with climate models is not long enough.
What will they say in 3 more years, ten more years is needed? Sheesh.
Charlie K (2:07 pm):
You mention the Warmists’ assumption of unstable equilibrium. Well said, that man! The vile expression “tipping point” has gone unchallenged for too long. When used in marine engineering the expression makes perfect sense, but in this context it’s misleading.
I’ve been wondering whether the whole AGW house of cards may come tumbling down if two misconceptions are exposed: (i) positive feedback and (ii) high sensitivity. Lo and benold, the brilliant Roy Spencer homes in on these two very areas. Are we at last seeing through the infernal complexity of this Great Climate Controversy? Can the AGW hypothesis be refuted by demonstrating that the climate is governed by negative feedback, and that the extra W/m2 of extra CO2 is trivial compared to, say, solar-driven albedo changes?
The end ain’t nigh. It’s outrageous that the good guys have to prove why and how li-li-li-li-life goes on.
Next thing you know, Nick Stokes will be convincing us the oceans really do warm from the bottom up 🙂
Can we not say that if positive feedback, were that what is going on, the climate long ago would have railed one way or the other, either hotter than, or colder than, either way uninhabitable. We know it’s been far warmer, and far cooler than today to say that the climate had not been able to recover from the condition, is just laughable on it’s face.
The earth’s climate pre-dates man, and forest fires, volcanoes, and destructive meteors have covered the globe with debris and ash, yet the earth and it’s atmosphere is still here. Positive feedbacks, due to their destructive power, do not exist in nature. Show me one example of such natural phenomena, with proof it exists.
Just one — No can do? Odd isn’t it.
I doubt seriously that anyone has discovered that mere trace gases can do any such thing, and for it to be the very first destructive positive feedback. Show the proof, not GIGO computer models.
Good read — I await your full paper Dr Spencer.
Nice work Roy. The climate sensitivity number is the real focus of the entire AGW debate. The AGW proponents bring us modeling results based upon an incomplete picture of natural variation. You bring us emperical evidence. And they never seem to be able to answer your evidence. That is why the debate is not only not resolved, but instead points rather strongly to no AGW issue of concern at all.
He is saying that since the feedback would lead to a 0.6C warming over an entire century given the value calculated shortly before this sentence, the current warming would have to be mostly derived from another source. If it weren’t then we could expect 0 warming for the rest of the century.
I would first comment that 5.78 watts/m2/K is almost exactly what the Stephan Boltzmann Equation predicts for surface temperatures in a no-feedback scenario (5.42).
Secondly, Trenberth published another paper in 2009 (besides the recent Missing Energy one) which has this very curious chart in it which is consistent with Dr. Spencer’s numbers.
It is the usual forcing diagram that the IPCC/Hansen produces but it has an additional box appended to it that you wouldn’t have seen before that includes all the “feedbacks expected” for the first time (water vapour and ice-albedo) (which are supposed to be about 200% of the straight AGW forcing in the long-run).
But to balance everything, he also introduces a new concept “Negative Radiative Feedback” which is the lack of positive feedback so far / the Missing Energy / Mysterious Negative Feedback / Error in the Theory. A whopping -2.8 watts/m2 of negative feedback / lack of positive feedback.
http://img638.imageshack.us/img638/8098/trenberthnetradiation.jpg
http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/EnergyDiagnostics09final2.pdf
skye:
“I wonder how Roy’s results compare to these empirical studies:”
Most of those type of studies that I have looked at seem to derive their results by looking at the correlation between CO2 and temperature. But they operate on the assumption that CO2 is driving climate rather that the alternative and very probable answer that climate is driving CO2. What I always find absurd about these studies is the way in which they ignore the turning points. Those times when CO2 continues to rise sharply while temperature seems to simply decide that it’s time to reverse directions. Or conversely, when CO2 is dropping and temperature then decides to start rising. If climate sensitivity where as high as they claim, this would be impossible, because there would be no natural element of variation that would be capable of overriding the assumed CO2 forcing.
Dr. Spencer, I just finished your book which gave a VERY good grounding for non-scientist like me. Because of your book, I was able to follow the looping/bias lines above that support your argument. Well done.
This article assumes that CO2 has been a cause of warming. Until all climate drivers are fully understood, no such assumption can be made. Increasing CO2 may be an effect of other changes such as increasing ocean temperature. Analysis of climate sensitivity does not lead to a valid conclusion that increasing CO2 will lead to any nett temperature increase.
tarpon says: “The earth’s climate pre-dates man, and forest fires, volcanoes, and destructive meteors have covered the globe with debris and ash, yet the earth and it’s atmosphere is still here. Positive feedbacks, due to their destructive power, do not exist in nature. Show me one example of such natural phenomena, with proof it exists.”
Actually, those forest fires you mention usually involve positive feedback. Fire creates updraft, updraft draws in additional air which increases the combustion rate. The fires stop generally when they run out of fuel or when the weather changes.
skye says: May 7, 2010 at 2:33 pm
I wonder how Roy’s results compare to these empirical studies:
If you read any of those studies and looked at the actual data they used, you will find the math is not done is the usual way math is done – as in 2+ 2 = 4 or 100 / 4 = 25
You will find the math is done as in 1 = 3 ; and our climate model simulation takes the empirical 1 data and matches it very well if we just change it to 3 ; and, CO2 increased by 100 ppm while temperatures fell by 2C and therefore the sensitivity is 3.0C per doubling; and, the volcano reduced net radiation by -4 watts/m2 while temperatures declined by -0.4C so our global warming estimate of +3.7 watts/m2 will result in a +3.0C increase in temperatures is accurate (the Pinatubo studies actually say this, it’s ridiculous).
Dr. Spencer.
“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. Look, my articles are not peer-reviewed science, people. I’m just keeping people abreast of progress in research they are paying me to do. :)”
Thanx for your candid input Roy. 🙂
I’m all for ‘open source’! It’s for the recipient to either include, or discard, any data from an open source feed dependant, mostly, on its quality, or the integrity of the recipient. With a diverse audience, you’re damned if you do and you’re damned if you don’t!
For one (me), I’m happy that you chose the ‘open’ road, as this gives me the opportunity of a more multifarious configuration of climate definition. 🙂
Best regards, Ray Dart.
@Tom in Florida says: May 7, 2010 at 3:20 pm
Obsessive compulsive people aren’t “average” people. Typically, they are fairly bright. However, it is very difficult for them to deal with anything random or unexplainable. In their view, there must be order and/or a method to deal with reality. This usually works fairly well. In this particular case, we’ve warmed a bit over the last century or so. They “need” an explanation. Anti-industrialists and Malthusians have provided an explanation, the CAGW hypothesis. They eagerly accept this explanation because it restores order and explanation for the world they live in. And, in turn, revile the people that caused the need to, yet again, follow another issue to explain and understand the world they live in. Some OCD people have already followed other issues related to climate enough to already understand the CAGW hoax is simply that. But only a few of us. The rest of us find beer and stack a pile of quarters in equal proportions that we keep for the pool game we’ll play once a week. But that’s only because I haven’t worked out how to use 1.6180339887 into the stacks. But then, that wouldn’t be good enough.
jeff brown says: “…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.”
There is a difference here, Dr. Spencer is using actual heat flux measurements, something that the Modelistas do not. The bulk of AGW “science” is based on trying to tease tiny warming signals out of chaotic temperature data covering a huge temperature range. The data interval requirements of the latter are much larger than for Dr. Spencers work.
I’ve been having trouble understanding the first figure, mainly what is meant by “change” in flux and T. Noting that the regression line passes through (0,0) it seems that “radiative flux change” means the difference between the flux at times t and the mean flux for the whole data set, while “T air change” means the difference between the temperature at times t and the mean temperature for the whole data set. The red points on the graph are the values of the flux at times t and the values of T at the same time t.
So the graph is directly showing that the flux is higher than average when T is higher than average, and lower than average when T is lower than average. That is, negative feedback: when T increases, the flux increases which leads to cooling and tends to return T to its average value; when T decreases, the flux decreases which leads to warming and again tends to return T to its average value. This is the opposite of the behaviour we would see if we are in the vicinity of a “tipping point”.
If I’ve understood that correctly I still can’t see what the blue lines are doing.
Bill Illis,
From the Trenberth paper you linked to:
“The excess in heat does several
things. (i) It warms the planet, increasing temperatures
that in turn increase the radiation back to space.”
And later
“As clouds have both a greenhouse effect and reflect solar
radiation, they can both heat or cool the Earth radiatively—
which of these dominates in a given region”
depends upon the cloud properties (e.g. coverage, height
and thickness). Generally there is large cancellation, but
averaged globally, it is the radiative cooling effect of
clouds that dominates.”
So that’s negative feedback he’s describing, no?
jeff brown
“you are missing the important ice-albedo feedback which is already showing to have an impact on Arctic temperatures, and then there is the permafrost/methane feedback, cloud feedbacks, ocean and atmospheric circulation feedbacks”
The important ice albedo feedback apparently led to a reversal in the arctic ice trend. Since the lowest recent point it has steadily regained area and density.
Permafrost methane is another of those interesting hypothesis which has also not demonstrated any additional warming IF it has even been shown to be happening.
”
Dirk at the summer solstice the north pole receives more incoming solar energy than anyplace else on earth.”
And handily reflects a large portion of it.
Where do you get this garbage. RC or Tamino’s rusty iron mind??
jeff brown says: “Milwaukee Bob, you are missing the important ice-albedo feedback which is already showing to have an impact on Arctic temperatures, and then there is the permafrost/methane feedback, cloud feedbacks, ocean and atmospheric circulation feedbacks. You can’t ignore the world’s refrigerator.”
The ice-albedo feedback is a Modelista fiction. Seawater albedos at high azimuth angles overlap those for ice. The permafrost/methane feedback is based on models, mere mathematical monkeybusiness. The Arctic ice extent this winter continued to grow for a full month longer than the average growth curve. Cloud feedbacks? You are make joke, Mr. Brown. The models have an inadequate grasp of cloud dynamics. I laugh ha-ha at your funny joke.
nedhead says:
May 7, 2010 at 4:02 pm
“So what I don’t understand from some of the comments is the that an enhanced GHG effect from CO2 has been confirmed by many observational studies. For example, satellite measurements of infrared spectra over the past 40 years show that less energy is escaping to space at the wavelengths associated with CO2.”
Can you give a reference for this? (Please, not IPCC AR4).
jorgekafkazar says:
“There is a difference here, Dr. Spencer is using actual heat flux measurements, something that the Modelistas do not. The bulk of AGW “science” is based on trying to tease tiny warming signals out of chaotic temperature data covering a huge temperature range. The data interval requirements of the latter are much larger than for Dr. Spencers work.”
Correct! Since Dr. Spencer is directly observing cause and effect, the length of the data set (7 years) is not important if the frequency of outcomes is consistent. Contrast this, for example, with someone attempting to indirectly provide evidence of AGW by pointing at the +0.7 K rise in the historical temperature record of ~ 150 years. In this case, even such a fairly long record is inconclusive since temperature changes of this magnitude are fairly common throughout the much longer paleo record. (That’s why it was important for the IPCC to deep-six the MWP and LIA in their various reconstructions). Putting it another way, if you have a well-constructed experiment (e.g., a fair coin), you don’t need a lot of trials before you converge to the correct answer.
kuhnkat says:
jorgekafkazar says:
“ice-albedo”……….how is it that “skeptics” are more up to date than the alarmists? It’s funny how they continually bring up the arctic yet the ice has significantly grown the past 3 years? Soon, they will tell us that climate change causes ice growth and we’re all going to die because of hot climate and ice growth!
Thank you Dr. Spencer.
This is another solid data point adding to your previous work that further supports the notion of low climate sensitivity. This is the keystone of the argument of natural versus anthropogenic effects.
The most shocking result I’ve seen with regard to sensitivity is Lindzen’s presentation of many climate models, showing the slope of ALL models to be virtually identical, with high climate sensitivity. This implies virtual certainty with regard to sensitivity (or at least a very narrow band of uncertainty). Yet the measured results were in the opposite direction. I’ve followed your previous analyses (and we have emailed each other about them a couple of years ago), and I understand your “squiggles”, for lack of a better term. They clearly show a strong negative feedback, which you have presumably again demonstrated (no details shown)
The response time, or “time constant” of the atmosphere with regard to feedback is for all practical purposes instantaneous. The atmosphere compared to oceans has virtually no heat capacity. Trying to measure feedbacks over weeks, months, or years is mixing fast-response effects with slow response effects. I think I may have written you about this, but the best way to measure climate response is to take the smallest resolution satellite IR information, and measure how it changes on an hourly basis in comparison to albedo (a proxy for clouds and thunderstorms). If the response is fast, which we already know it is, then small effects such as CO2 , even at their theoretical limits, are meaningless. The other area of study that is important is convection. Since your and many others’ studies show the effectiveness of thunderstorms in heat dissipation, especially in the tropics, we need to quantify the radiative effects of still (wet) air in the morning, before thunderstorms develop, compared to radiative effects of full-blown thunderstorms in the afternoon where heat is carried aloft to the level where the effects of any barriers to heat escape to space are minimal. This seems like a perfectly regulating system, simply by the parameters of the logarithmic density of air with altitude. Period.
What I’m saying, Dr. Spencer, is that resolution of observation is key to determining actual feedback. Measuring OLW radiation and ISW on the trailing edge of a thunderstorm, compared to the leading edge, will give you the short term response rate. Any resolution larger than that required to describe a convective storm will tend to underestimate feedback. Feedback is a very sharp function. Our inability to describe it is a function of lack of resolution.
William M. Gray and Barry Schwartz came out with a very interesting study that complements your conclusions. There are many others I know you are aware of that hover around the 0.5°C per doubling of CO2. The Association of Outgoing Radiation with Variations of Precipitation – Implications for Global Warming by William M. Gray and Barry Schwartz
http://climaterealists.com/index.php?id=5668
Anyway, Dr. Spencer, could you respond to the relationship between measurement resolution and implied sensitivity?
Thank you,
Mike S.
I would be very interested in how these data compare to Zágoni’s expansion of the energy balance equations to allow for finite atmospheric thickness. Zágoni examined the simplifying assumptions in current models’ boundary conditions, formulated some 80 years ago, and took them beyond the infinite atmosphere assumption. His solution clearly demonstrates the negitive feedback missing in the simplified equations, and reportedly fit both terestrial and Martian data extremely well.
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. The crumbling house of cards swirling in the toilet analogy has been used by me and others.
What makes the skeptic position move into the mainstream media and ends the world wide diversion of human energy and money into the AGW sinkhole? More research or Republican control of a House or Senate committee or Australian politics?
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.