Last year I posted an analysis of satellite observations of the 2007-08 global cooling event, showing evidence that it was due to a natural increase in low cloud cover. Here I will look at the bigger picture of what how the satellite-observed variations in Earth’s radiative budget compare to that expected from increasing carbon dioxide. Is there something that we can say about the relative roles of nature versus humanity based upon the evidence?
What we will find is evidence consistent with natural cloud variations being the dominant source of climate variability since 2000.
CERES Observations of Global Energy Budget Changes
The following graph shows the variations in the Earth’s global-average radiative energy balance as measured by the CERES instrument on NASA’s Terra satellite. These are variations in the imbalance between absorbed sunlight and emitted infrared radiation, the most fundamental quantity associated with global warming or global cooling. Also show (in red) are theoretically calculated changes in radiative forcing from increasing carbon dioxide as measured at Mauna Loa.
Since there is some uncertainty in the absolute accuracy of the CERES measurements, where one puts the zero line is also somewhat uncertain. Therefore, it’s the variations since 2000 which are believed to be pretty accurate, and the exact dividing line between Earth gaining energy and Earth losing energy is uncertain. Significantly, all of the downward trend is in the reflected sunlight portion, not the infrared portion of the variations. We similarly can not reference where the zero line should be for the CO2 forcing, but the reasons for this are more complex and I will not address them here.
In order to compare the variations in the CO2 forcing (in red) to the satellite observations, we need to account for the fact that the satellite observes forcing and feedback intermingled together. So, let’s remove a couple of estimates of feedback from the satellite measurements to do a more direct comparison.
Inferred Forcing Assuming High Climate Sensitivity (IPCC View)
Conceptually, the variations in the Earth’s radiative imbalance are a mixture of forcing (e.g. increasing CO2; clouds causing temperature changes), and feedback (e.g. temperature changes causing cloud changes). We can estimate the forcing part by subtracting out the feedback part.
First, let’s assume that the IPCC is correct that climate sensitivity is pretty high. In the following chart I have subtracted out an estimate of the feedback portion of the CERES measurements based upon the IPCC 20-model average feedback parameter of 1.4 W m-2 K-1 times the satellite AMSU-measured tropospheric temperature variations
As can be seen, the long-term trend in the CERES measurements is much larger than can be accounted for by increasing carbon dioxide alone, which is presumably buried somewhere in the satellite-measured signal. In fact, the satellite observed trend is in the reflected sunlight portion, not the infrared as we would expect for increasing CO2 (not shown).
Inferred Forcing Assuming Low Climate Sensitivity (”Skeptical” View)
There has been some published evidence (our 2007 GRL paper, Lindzen & Choi’s 2009 paper) to suggest the climate system is quite insensitive. Based upon that evidence, if we assume a net feedback parameter of 6 W m-2 K-1 is operating during this period of time, then removing that feedback signal using AMSU channel 5 yields the following history of radiative forcing:
As can be seen, the relative size of the natural forcings become larger since more forcing is required to cause the same temperature changes when the feedback fighting it is strong. Remember, the NET feedback (including the direct increase in emitted IR) is always acting against the forcing…it is the restoring force for the climate system.
What this Might Mean for Global Warming
The main point I am making here is that, no matter whether you assume the climate system is sensitive or insensitive, our best satellite measurements suggest that the climate system is perfectly capable of causing internally-generated radiative forcing larger than the “external” forcing due to increasing atmospheric carbon dioxide concentrations. Low cloud variations are the most likely source of this internal radiative forcing. It should be remembered that the satellite data are actually measured, whereas the CO2 forcing (red lines in the above graphs) is so small that it can only be computed theoretically.
The satellite observed trend toward less energy loss (or, if you prefer, more energy gain) is interesting since there was no net warming observed during this time. How could this be? Well, the satellite observed trend must be due to forcing only since there was no warming or cooling trend during this period for feedback to act upon. And the lack of warming from this substantial trend in the forcing suggests an insensitive climate system.
If one additionally entertains the possibility that there is still considerable “warming still in the pipeline” left from increasing CO2, as NASA’s Jim Hansen claims, then the need for some natural cooling mechanism to offset and thus produce no net warming becomes even stronger. Either that, or the climate system is so insensitive to increasing CO2 that there is essentially no warming left in the pipeline to be realized. (The less sensitive the climate system, the faster it reaches equilibrium when forced with a radiative imbalance.)
Any way you look at it, the evidence for internally-forced climate change is pretty clear. Based upon this satellite evidence alone, I do not see how the IPCC can continue to ignore internally-forced variations in the climate system. The evidence for its existence is there for all to see, and in my opinion, the IPCC’s lack of diagnostic skill in this matter verges on scientific malpractice.
I can’t say I understand what information is being shown here. Seems to me that CLOUDS should do exactly the opposite of CO2; while water vapor should either cool or warm, depending on whether you are talking solar spectrum or surface LWIR.
But the first graph suggests that clouds are doing the same as CO2 in spades.
Are these plots of extraterrestrial radiation FROM the earth; and what is the wavelength range included.
So is the Earth’s climate a pendulum or a gyroscope? Does it swing between the extremes while trying to slow down to a lower energy state and finally end up at rest, while different things keep nudging and whacking it? Or does it have its own position that it firmly wants to maintain, pushing back against any force that tries to move it, with very strong forces able to push it into a different preferred position?
Another excellent educational post by Dr. Spencer.
WRT where at the end he sez:
”I do not see how the IPCC can continue to ignore internally-forced variations in the climate system. . . . . the IPCC’s lack of diagnostic skill in this matter verges on scientific malpractice.”
Yea verily; from the perspective of objective science.
But of course there is another major factor at work here:
The huge vested interest of the world-wide AGW ”industry”; and especially its most prominent leaders and advocates; i.e.:
FOLLOW THE MONEY; and note who is most at risk of losing funding if the whole AGW house of cards finally collapses. . . .
Water – excellent energy buffer !
Plant more trees !
I’m still wondering where this “pipeline” is located… Saudi Arabia? Georgia? The Sahara? Putting a decade of “we’re all going to burn up and die” heat into a pipeline has got to take a pretty big pipe… Don’t see it on the Satellite photos though… 😉
The last sentence of this post “The evidence for its existence is there for all to see, and in my opinion, the IPCC’s lack of diagnostic skill in this matter verges on scientific malpractice.” will be read as harsh by most people. However; after searching the working group one report of AR4 it could be read as generously granting good motives for the oversight.
Searching http://www.ipcc.ch/ for ‘clouds’ yields 540 hits mostly admitting that the effect of clouds is unknown. But the unknown did not stop the IPCC from building assumptions about clouds into their models that are consistent with external forcing from CO2.
The first hit shows that the IPCC knew about the effect of cosmic rays on cloud formations but choose to discount the effect. The first of the 540 hits is excerpted below. Looking through the hits and analyzing how little the IPCC admitted to knowing about such a major factor lowered my confidence in their modeling skills to zero.
“Working Group I: The Scientific Basis
6.11.2.2 Cosmic rays and clouds
Svensmark and Friis-Christensen (1997) demonstrated a high degree of correlation between total cloud cover, from the ISCCP C2 data set, and cosmic ray flux between 1984 and 1991. Changes in the heliosphere arising from fluctuations in the Sun�s magnetic field mean that galactic cosmic rays (GCRs) are less able to reach the Earth when the Sun is more active so the cosmic ray flux is inversely related to solar activity.
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We conclude that mechanisms for the amplification of solar forcing are not well established. Variations in ultraviolet and solar-induced changes in O3 may have a small effect on radiative forcing but additionally may affect climate through changing the distribution of solar heating and thus indirectly through a dynamical response. At present there is insufficient evidence to confirm that cloud cover responds to solar variability.”
davidmhoffer:
I’m sure you meant +1.00% at the pole. 🙂
davidmhoffer:
I’m sure you meant +1.00% at the pole. 🙂
Once again Dr Christy thank you for a clear and logical development of your arguments.
George E. Smith (11:39:01) :
I’m with you George. The data doesn’t seem to make sense. The CERES data is measurement, no feedback terms should be required or used. I also hate the use of the term forcing, it make no sense to me when I’m looking at servo systems.
DaveE.
People, follow the link at the start of the article and read that first. It explains what’s being measured.
The funny thing seems to be that ATM the earth emits less radiation than it receives even though we see a pretty cold winter in the northern hemisphere. So where does this energy end up? Nobody knows.
Even more important is the fact that the temporary imbalances in the earth’s radiation balance are far greater than even the exaggerated forcing effects of anthropogenic CO2.
Now this is maybe a dumb question: But as the satellite scans earth’s light side, can the reason for the huge energy imbalances maybe be caused by changes in the emitted radiation on the dark side, in other words, nighttime radiation? At least that’s how i understood the way the satellite works.
I was always taught in my engineering courses to go back and do “sanity check” calculations at the completion of each problem. The idea being that if the answer doesn’t look even plausible, it probably is not. To me, this is the essence of Global Warming it its entirety. There’s just no way that humans can have any kind of impact on a chaotic system on the order of the earth, with the atmosphere, oceans, solar and galactic forces, negative feedbacks, etc. They all simply dwarf us. If you look at how little of the earth’s actual area that humans even occupy, you realize quickly that with all of the water, ice, mountains, deserts, etc. that the earth is essentially uninhabited.
Good to see the science backs up the sanity checks.
Research by climate experts has surprising results.
Or as one commentator quips.
We can’t account for the lack of hurricanes and its a travesty that we can’t.
http://www.news.com.au/couriermail/story/0,23739,26581533-3102,00.html
It’s a travesty.
Well, according to Trenberth anyway. I think Ceres was what he was referring to when he said the energy balance is off. We should be warming but we’re not.
It’s not a travesty. It’s odd. It’s a ‘huh’ moment. After which usually a re-think occurs and breakthroughs are made. Usually.
This will surprise warmers and coolers alike. The only ones who won’t be surprised by this graph are, well, the actual deniers!
Which makes Spencer’s work not only extremely important, but gives me a chuckle.
Has Dr Roy discounted the possibility that a quieter sun since 2003 might have something to do with the situation?
The third chart, flipped upside down looks like global temperature trend. There is a change in 2005-2003 and each La Nina (2000, 2008) shows that more clouds are generated, cooling the earth. Clouds rulezz.
Maybe you should check out this webpage: http://gustofhotair.blogspot.com/
which shows s significant decrease in cloud cover in the last 50 years. This decrease in cloud cover occurs only during the day, with steady rates at night. Temperatures have not been increasing at night but only during the day. Cloud cover is shown to be strongly related to temperature, and it will show that 75% of all warming is caused by cloud cover and proper statistical analysis of temperature.
Can someone tell me this… it isn’t related to CO2, but another man-made concept. The amount of the earth that has been covered with asphalt and concrete, that is exposed to the sun re-radiates how much heat? I am not talking about minor heat islands, I am talking about the entire planets man-made radiators.
My house, at night, after the sun sets radiates so much heat (brick) I can put my hand a few inches away and feel it. Now multiply that by every concrete/brick home, roadway, etc., then add asphalt in the same manner and we have a good bit of radiative heat. It may be NOTHING… but, the world is getting paved over and that MUST have some effect of warmer nights, at least.
Am I completely wrong, or somewhat wrong? After all, it is an observation that can be seen and felt… and every year the amount increases… hopefully it will stop.
I was hoping for some comment, although I do realize it is off this topic, but seems like another factor completely ignored, as we have seen at Darwin, for example.
From Climate Change Reconsidered:
Chapter 2. Feedback Factors and Radiative Forcing (PDF, 384 kb)
2.1. Clouds (PDF, 50 kb)
@ur momisugly Eric Smith (10:09:41) :
Jasper Kirkby, a British experimental particle physicist currently with CERN, Switzerland presents a lecture in which cosmic rays show a strong correlation with global temperature over short and long time periods.
http://cdsweb.cern.ch/record/1181073
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Thank you for that. I have just watched it – absolutely fascinating; and very definitely shows that there is sun-cosmic-climate connection which they are investigating.
Steve M. (12:02:18) :
davidmhoffer:
after warming +.25 K at equator:
mean temp at equator 300.25 K (+0.08%)
meant temp at pole 202 K (+2.00%)
I’m sure you meant +1.00% at the pole. 🙂
OOOPS! Well if I make the temp at the pole 100 K then my final number would fit the data…yes that’s it 🙂
But I think my theory still stands. Even at only 1% that’s still a huge boost in radiance at the pole relative to the over all temperature increase.
The 6 W graph is very close to the inverted temp graph. Is that an indication of 6 W feedback being close to correct?
“The satellite observed trend toward less energy loss (or, if you prefer, more energy gain) is interesting since there was no net warming observed during this time. How could this be?”
Could it be that there is less energy loss and no net warming because there has been reducing solar energy output, particularly in the UV range?
TanGeng (10:37:40) :
Seems like some numbers that have a lot of uncertainty. I still don’t understand this conclusion. It seems to suggest that heat is being stored somewhere in some form that isn’t being measured by temperature, either lot of ice is melting, it’s being stored chemically in some form somewhere, or it’s someplace where we aren’t measuring.
My first thought was that in 1998 there was a super El Niño-Southern Oscillation event that spiked global temperatures. Basically the tropical Pacific burped a lot of heat. Looks like the earth was shedding that heat up to (within the error of the CERES instrument) sometime in 2004.
But then I recalled that Dr. Spencer said, “Significantly, all of the downward trend is in the reflected sunlight portion, not the infrared portion of the variations.” What is going “down” is the energy emitted by the earth relative to the energy that the earth is receiving. “… in the reflected sunlight portion …” means that the earthshine is dimming. I would infer that the infrared “blackbody” radiation that the earth gives off into space is not decreasing.
Maurice Garoutte said:
Searching http://www.ipcc.ch/ for ‘clouds’ yields 540 hits mostly admitting that the effect of clouds is unknown. But the unknown did not stop the IPCC from building assumptions about clouds into their models that are consistent with external forcing from CO2.
As a bog standard member of the public this is what bothers me about the IPCC. A very wide spectrum of science and scientific opinion, both for and against CO2 warming the Earth, both for and against man being behind the warming, both for and against the Earth warming substantially and even whether warming would be bad, come together and are mashed into documents for policymakers that say matter of factly that it is warming, it is because of man and if we don’t do something now it will be a catastrophy for everyone some time in the future.
There is a great deal of uncertainty in climate science but for political reasons the uncertainties are shuffled out of sight, minimised, ridiculed and so on in order to achieve a consensus. That isn’t science.