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.
Dr Spencer
You should take a look at the whole satellite cloud series as your missing the best bit.
Average cloud cover dropped by 4% and the step change that happened leads the step change we saw in temp at the end of the 90s.
That 4% has been calculated at 3.5w/m2, nearly the same as the 3.7w for CO2 doubling.
It only resulted in a o.4degC increase in temp when no feedback would indicate at least 1 deg.
Interesting how you got almost that exact result, well done 🙂
Jack Maloney says:(May 7, 2010 at 2:34 pm)
“GLOBAL WARMING FEARS SEEN IN OBSESSIVE COMPULSIVE DISORDER PATIENTS
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…We found that many obsessive compulsive disorder patients were concerned about reducing their global footprint,” said study author Dr Mairwen Jones.”
This study shows how the doom and gloom of AGW hysteria can have a negative effect on the average person. Perhaps Algore et al should foot the bill for therapy for these poor souls.
evanmjones at 2:38 pm; said to:
jeff brown at 1:54 pm
And I find it curious that the analysis is limited to 60S to 60N. Many of the feedbacks that enhance warming of the planet are found in the polar regions,…. “Well, surface data from outside those regions is mostly less than useless …… ice reflection issues that affect MW readings.”
And – – does not the sparsity of polar temp. data “at altitude” make the theory of polar feedbacks impossible to prove (or disprove) AND do not ALL of those 17 IPCC climate models (the analysis references) “call for” the feedbacks to be in the trop. between 60S-60N? THAT is where the high “sensitivity” is suppose to be….
Where has the ‘hidden heat’ gone?
On it’s merry way to join with Pioneer and Voyager.
AWOF – away without feedback.
“jeff brown says:
[…]
Many of the feedbacks that enhance warming of the planet are found in the polar regions,[…]”
Positive feedbacks? Negative feedbacks? Which feedback exactly? “Many”? 5? 20?
Yeah, there’s the albedo conjecture, but even in summer the rays come in at a low angle so it doesn’t make a difference (total reflection on sea surface). Name your postulated feedbacks.
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.
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.
Dr. Spencer apparently has done it again. I look forward to reading his paper, to get all the details of the methodology. I for one have been calling for these models to be properly calibrated. Perhaps this is one of those calibrations. If this holds up, and I am hopeful it will, it should be another falsification of the AWG hypothesis.
Studies cited above about feedback predictions are not empirical, they are extrapolations from prior guesstimates of temperature and CO2 changes but made in a dynamic system that is changing for other reasons (orbital changes taking the Earth into or out of an ice age). If the feedback loops were strongly positive we should actually see runaway warming during interglacials as rising CO2 warms the oceans that belch more CO2 and cause more warming etc. In fact the process stops on its own.
Most feedback effects are not at the polar regions, as there is just not that much sunlight hitting those areas in the first place, the vast majority of the Earth’s surface and incident radiation strikes between 60 deg S and N. The poles are dark half the year anyway.
If Spencer is correct, then it follows that the modest rise in CO2 concentrations in the 20th century would have only caused .2 deg or so of warming, making the bulk of the 20th cent warming naturally induced (albeit unexplained mechanistically). Spencer’s satellite data shows about .3 deg rise in GAT since 1980, and I guess most of that is CO2 induced. But at that rate we only rise 1 deg for rest of the century, and that is probably an overestimate.
No matter what the CO2 feedback, there is a law of diminishing returns that operates, the warming for each subsequent 100 ppm rise in CO2 has to be less than the previous, if it was accelerating, then we should have seen runaway interglacials, but we clearly don’t, and a generally unstable climate history for the Earth with wild swings in short periods, we don’t see that. The ice age cycles are clearly dominated by orbital changes and not CO2 for example.
One of the biggest problems with AGW is that it can’t explain why the last interglacial was so much warmer than the present. 100kya the Earth was several degrees warmer, sea levels much higher, and hippos swam in the Thames. Another interglacial 850kya melted off the entire Greenland ice cap. If our GCM were really reliable they should be able to generate those results.
Models?
Everytime we hear about models. Models can tell you anything. Models are your best friend.
Please stop this model nonsense we want data, measured.
DirkH says:
May 7, 2010 at 3:28 pm
Dirk at the summer solstice the north pole receives more incoming solar energy than anyplace else on earth.
Interesting stuff, especially the comparison with IPCC models. I assume the numbers from the models are also based on 60S to 60N?
Jeef Brown & Wildred:
Seven years of monthly data represents approximately 84 observations depending on start and end months… how many do you propose are required for the results to be significant?
a few answers:
Ice near the poles won’t melt if most of the global atmosphere at lower latitudes does not warm. Atmospheric feedbacks kick in faster than ice-albedo feedbacks. And, has been mentioned, the satellite data are not as good at the high latitudes, anyway.
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. 🙂
The global cloud cover data are not good enough to do long-term trends with. Until the Terra MODIS data started in 2000, we could not be confident of any long-term cloud changes people think they see in the satellite data. Only a 2% change is needed to cause global warming or cooling. Long-term cloud changes on a regional basis can fool you because an increase in cloudiness in one region is usually compensated for by a decrease in an adjacent region.
Yes, it’s only 7 years of data. But the fact that none of the climate models show the negative feedbacks the satellites show when those are computed the same way — on the same time scale — from climate model output strongly suggests something might be wrong with those models’ feedbacks….
…does this all sound like “the science is settled”?
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.
Also, observations at the earth’s surface show there is more downward infrared radiation reaching the surface. Of course this can be from other factors than CO2, such as water vapor which is more important as a GHG anyway, though I don’ t know if any studies have looked at the direct affect from water vapor.
Anyway, I agree with Wildred, 7 years of data to make conclusions for the end of this century? That seems like bad science to me. And it’s extrapolation from 7 years of data w/out any consideration of the physical earth-atmosphere sytem
The current crop of climate models used that 2 to 4 feedback range, then have been curve-fit in other areas to match the historical record. Would changing the feedback to Dr Spencer’s value of 6 require wholesale readjustments, or would the resulting output more closely match the real climate to begin with? Running the models with the 6 feedback value shouldn’t take too much more funding, just a little typing on the keyboard and some computer time.
I hope is paper is more accurate and informative than his blog post.
REPLY: In your case, I don’t think it would matter. -A
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>>
You are confusing building a model and extrapolating climate from it and measurements to determine if the physics upon which the models are based are accurate. What Dr Spencer is showing is that the measured negative feedbacks are much larger than those assumed by the models, and what the models would arrive at if they were adjusted to reflect actual measured instead of estimated numbers. He did not set out to determine a long term trend, he set out to determine if the energy imbalance predicted by the models is accurate, and measurements from the available data show that it is not.
Dr. Spencer.
A N/S 60° Latitude, beneath the Feral Cell, looks like a good region for observation with minimal interference from Earth’s rotational forces. Well thought!
With what would you associate this ‘strong -ive feedback’? Would it be the ‘latent convective component’ and ‘cloud altering albedo’ aspects of the hydrological cycle perchance?
It certainly looks all -ive ‘forcing’ without any radiative +ive, but why worry about that when the radiative +ive only leaves the atmosphere following a +ive displacement to higher altitude by the hydrological cycle! Isn’t that what the ‘greenhouse effect’ (GHE) is all about?
Best regards, Ray Dart.
“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.”
That’s absurd. Your method is just correlation of observed temperature vs observed radiation. It can’t tell you anything about the cause of warming.
Your first regression is of global IR vs ocean temperatures. This really biases the case; global IR responds to global temp, which is a lot more variable than ocean temp. And it leaves out the Arctic, which is even more variable.
“Roy writes: 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.” Indeed, this is true and follows from the fact that atmospheric CO2 has increased about 40% since the mid 1800s, so that with a climate sensitivity of 0.5 deg C for doubling, only about 0.2 deg C can be ascribed to CO2.
N.B. Roy’s results seem quantitiatively similar to Lindzen-Choi (2009), which has driven some to distraction… or worse.
Thanks Dr. Spencer for finding Kevin’s missing heat.
http://www.jstage.jst.go.jp/article/sola/5/0/53/_pdf
All real tests of climate models, including perfect model tests, have shown them to be predictively useless. Now, we have a strikingly new result from Dr. Spencer giving us the same conclusion yet once again.
So far, most climate modelers, and the IPCC in particular, have completely ignored the results showing their hot future predictions mean nothing. They go on telling the same story, no matter what, keeping their eyes fixed forward and their ears apparently stoppered. The press generally goes along and politicians are inherently incapable of changing their announced policies.
The question is, then, will Dr. Spencer’s new results be roundly ignored and get consigned to the same political garbage can as all the rest of the results showing the worthlessness of AGW science, so-called.
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. 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. :)”
Thanks for keeping it simple, Dr. Spencer! I am a fly fisher with a strong interest in climate science. (No actual knowledge or skills.) Bombard your opponents with the heaviest scientific terms, and give the easy versions to the fly fishers around the world;-)