by Roy W. Spencer, Ph. D.
What can we learn from the IPCC climate models based upon their ability to reconstruct the global average surface temperature variations during the 20th Century?
While the title of this article suggests I’ve found evidence of natural climate cycles in the IPCC models, it’s actually the temperature variability the models CANNOT explain that ends up being related to known climate cycles. After an empirical adjustment for that unexplained temperature variability, it is shown that the models are producing too much global warming since 1970, the period of most rapid growth in atmospheric carbon dioxide. This suggests that the models are too sensitive, in which case they are forecasting too much future warming, too.
Climate Models’ 20th Century Runs
We begin with the IPCC’s best estimate of observed global average surface temperature variations over the 20th Century, from the “HadCRUT3″ dataset. (Monthly running 3-year averages are shown throughout.) Of course, there are some serious concerns over the validity of this observed temperature record, especially over the strength of the long-term warming trend, but for the time being let’s assume it is correct (click on image to see a large version).
Also shown in the above graph is the climate model temperature reconstruction for the 20th Century averaged across 17 of the 21 climate models which the IPCC tracks. To provide a reconstruction of 20th Century temperatures included in the PCMDI archive of climate model experiments, each modeling group was asked to use whatever forcings they believed were involved in producing the observed temperature record. Those forcings generally include increasing carbon dioxide, various estimates of aerosol (particulate) pollution, and for some of the models, volcanoes. (Also shown are polynomial fits to the curves, to allow a better visualization of the decadal time scale variations.)
There are a couple of notable features in the above chart. First, the average warming trend across all 17 climate models (+0.64 deg C per century) exactly matches the observed trend…I didn’t plot the trend lines, which lie on top of each other. This agreement might be expected since the models have been adjusted by the various modeling groups to best explain the 20th Century climate.
The more interesting feature, though, is the inability of the models to mimic the rapid warming before 1940, and the lack of warming from the 1940s to the 1970s. These two periods of inconvenient temperature variability are well known: (1) the pre-1940 warming was before atmospheric CO2 had increased very much; and (2) the lack of warming from the 1940s to the 1970s was during a time of rapid growth in CO2. In other words, the stronger warming period should have been after 1940, not before, based upon the CO2 warming effect alone.
Natural Climate Variability as an Explanation for What The Models Can Not Mimic
The next chart shows the difference between the two curves in the previous chart, that is, the 20th Century temperature variability the models have not, in an average sense, been able to explain. Also shown are three known modes of natural variability: the Pacific Decadal Oscillation (PDO, in blue); the Atlantic Multidecadal Oscillation (AMO, in green); and the negative of the Southern Oscillation Index (SOI, in red). The SOI is a measure of El Nino and La Nina activity. All three climate indicies have been scaled so that their net amount of variability (standard deviation) matches that of the “unexplained temperature” curve.
As can be seen, the three climate indices all bear some level of resemblance to the unexplained temperature variability in the 20th Century.
An optimum linear combination of the PDO, AMO, and SOI that best matches the models’ “unexplained temperature variability” is shown as the dashed magenta line in the next graph. There are some time lags included in this combination, with the PDO preceding temperature by 8 months, the SOI preceding temperature by 4 months, and the AMO having no time lag.
This demonstrates that, at least from an empirical standpoint, there are known natural modes of climate variability that might explain at least some portion of the temperature variability seen during the 20th Century. If we exclude the post-1970 data from the above analysis, the best combination of the PDO, AMO, and SOI results in the solid magenta curve. Note that it does a somewhat better job of capturing the warmth around 1940.
Now, let’s add this natural component in with the original model curve we saw in the first graph, first based upon the full 100 years of overlap:
We now find a much better match with the observed temperature record. But we see that the post-1970 warming produced by the combined physical-statistical model tends to be over-stated, by about 40%. If we use the 1900 to 1970 overlap to come up with a natural variability component, the following graph shows that the post-1970 warming is overstated by even more: 74%.
Interpretation
What I believe this demonstrates is that after known, natural modes of climate variability are taken into account, the primary period of supposed CO2-induced warming during the 20th Century – that from about 1970 onward – does not need as strong a CO2-warming effect as is programmed into the average IPCC climate model. This is because the natural variability seen BEFORE 1970 suggests that part of the warming AFTER 1970 is natural! Note that I have deduced this from the IPCC’s inherent admission that they can not explain all of the temperature variability seen during the 20th Century.
The Logical Absurdity of Some Climate Sensitivity Arguments
This demonstrates one of the absurdities (Dick Lindzen’s term, as I recall) in the way current climate change theory works: For a given observed temperature change, the smaller the forcing that caused it, the greater the inferred sensitivity of the climate system. This is why Jim Hansen believes in catastrophic global warming: since he thinks he knows for sure that a relatively tiny forcing caused the Ice Ages, then the greater forcing produced by our CO2 emissions will result in even more dramatic climate change!
But taken to its logical conclusion, this relationship between the strength of the forcing, and the inferred sensitivity of the climate system, leads to the absurd notion that an infinitesimally small forcing causes nearly infinite climate sensitivity(!) As I have mentioned before, this is analogous to an ancient tribe of people thinking their moral shortcomings were responsible for lightning, storms, and other whims of nature.
This absurdity is avoided if we simply admit that we do not know all of the natural forcings involved in climate change. And the greater the number of natural forcings involved, then the less we have to worry about human-caused global warming.
The IPCC, though, never points out this inherent source of bias in its reports. But the IPCC can not admit to scientific uncertainty…that would reduce the chance of getting the energy policy changes they so desire.
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Dave N (16:47:43) :
@RichieP:
“Perhaps the Guardian is attempting to present a “balanced” view (ie examples of support from both sides)?”
Well that would be a first!
ET (22:10:54) :
Do you have any papers on what drives the solar cycles internally within the sun, […]
Sounds rather convenient to discount the magnetic field
The magnetic field is not discounted, it is solar activity. A good paper on the Rise and Fall of the First Solar Cycle Model is http://www.leif.org/research/Rise-and-Fall.pdf
Mark Sawusch (21:28:45)
“yes but PDO+AMO v. Temp: R²=.83
PDO+AMO+”sunspot integral” v. Temp: R²=.96”
Questions:
1) Are you using monthly data?
2) Are these r^2 values for the 5 year moving average?
” RB (17:44:55) :
DirkH,
You do know that positive feedback does not imply runaway instability, don’t you? What are you basing your ‘they are hiding the exponential runaway’ comment on?”
In general you are right. I said:
“We could think of it as the addition of two models, one with, say an exponential runaway and one with a stable oscillation. Over time though, the exponential wins and the instability dominates the system. Like Hansen predicted for 2000 in a prediction from 1981 i think, his first warming-catatrophe paper. He said that in 2000 the runaway would totally dominate any natural variability. As we know now, he was 12 years off ;-)”
What’s your problem with that? I was constructing an example along the lines of Hansen’s well-known predictions. I did not say that somebody hides an exponential runaway, where did you read that?
Oliver K Manuel,
When you say that atrology is more robust science than the theory of a hydrogen rich sun, I presume you are emphasising the rubbishness of the latter theory rather than the merits of the former?
I have followed your link where you explained that the sun mostly consists of iron, but does not this create a whole lot more questions?
1) Calculations of the sun’s lifespan are based on fusion of H to He. Have you recalculated based on iron?
2) Iron does not fuse without absorbing energy to do so. What is the main source of energy if not hydrogen?
3) Does an iron content alter our understanding of the mass of the sun?
4) Why would the sun be iron rich when the most abundant element in the universe is hydrogen?
5) What kind of spectal emissions would we expect from an iron sun? Would they be different from a hydrogen sun?
Dear Dr. Spencer,
I’m just a layman, but ….
What happens if you remove or minimize the “aerosol cooling” effect? Do you get a better fit? “Aerosol cooling” always seemed like a bit of a kludge to me to make the data fit because of the mistake of leaving out significant natural oscillations from their models. But it’s only a hunch, so I could be wrong …
Leif Svalgaard (02:22:36) :
“The magnetic field is not discounted, it is solar activity.”
Perhaps easier to understand when: Tidal perturbation to a great ball of plasma moves some plasma around and generates strong electrical currents, strong electrical currents generate strong magnetic fields that can breach the solar photosphere. Thus, sunspots that permit more energetic radiation to emerge from lower in the solar atmosphere.
Knock me down in flames if you want, but that’s my best simple definition. It’s also another ‘natural variability’ that is the only realistic ‘forcing to climate’ besides orbital aberration etc. Especially when wavelengths just short of visible light are given the greater depth of ocean penetration.
Interesting discussion.
Best regards, suricat.
I have a fundamental question. Is climate behaviour dermined by the chaos theory? Are there any scientific papers on this subject?
If chaos is the dominant driver, then currently it is not possible to predict future events.
1. Invariant (15:17:27) : “The sun is invariant.”
2. Oliver K. Manuel (20:37:09) : “Really? The Sun is the center of mass of the entire universe? It doesn’t wiggle? It doesn’t change? There are no solar cycles?
Did one of IPCC’s Nobel Prize winning scientists give you this information?”
3. Leif Svalgaard (20:48:33) : “The Sun is in free fall, so doesn’t feel any wiggling.”
There are no solar cycles? “They are caused by processes internal to the Sun”
– – – – –
So it is Leif, rather than another one of IPCC’s Nobel Prize winning scientists who is spreading propaganda of an invariant Sun!
Bull! The entire universe is evolving and changing. Can you imagine a universe in which the one and only invariant point happens to be Earth’s heat source!
That is a basic assumption of CO2-induced global warming!
Leif says that the Sun “doesn’t feel any wiggling.” Now ask yourself why he, or any real scientist, would try to convince you that Earth’s heat source is invariant although every other object in the universe “wiggles”?
Is someone trying to keep the Climategate scandal contained, so it doesn’t also expose NASA’s sordid record of promoting lies and ignoring experimental data!
Experimental data that shows the Sun is the unstable remains after the Sun exploded 5 Gy (5 x 10^9) years ago and ejected all of the material that now orbits it:
http://www.omatumr.com/Data/1972Data1.htm
http://www.omatumr.com/Data/1975Data.htm
http://www.omatumr.com/Data/1976Data.htm
http://www.omatumr.com/Data/1983Data.htm
http://www.omatumr.com/Data/1991Data.htm
http://www.omatumr.com/Data/1993Data.htm
http://www.omatumr.com/Data/1994Data.htm
http://www.omatumr.com/Data/1996Data.htm
http://www.omatumr.com/Origin.htm
Only a few of these measurements were made in my laboratory:
http://www.omatumr.com/Data/MassSpec.htm
With kind regards,
Oliver K. Manuel
Former NASA PI for Apollo
DirkH,
When you say
But the existing GCMs are tuned to incorporate assumed positive feedbacks, otherwise they would not produce alarming results. They are inherently unstable by design. For such a system, the initial conditions lead to ever-amplifying oscillations or a push over the brink straight ahead,
this is a statement without any foundation. It implies a lack of good understanding of positive feedback with regards to implications for unbounded growth. Unless appropriate conditions are met, positive feedback results in damped oscillations, not ever-amplifying oscillations. This is a meme that is frequently and erroneously circulated on the web, I see no evidence in your statements that yours was not along the same lines.
Vincent (05:46:11), I will insert answers (A) between your questions (Q) below:
“Oliver K Manuel,
Q: “When you say that a(s)trology is more robust science than the theory of a hydrogen rich sun, I presume you are emphasising the rubbishness of the latter theory rather than the merits of the former?”
A: Yes.
Q: “I have followed your link where you explained that the sun mostly consists of iron, but does not this create a whole lot more questions?”
A: Yes.
Q: 1) “Calculations of the sun’s lifespan are based on fusion of H to He. Have you recalculated based on iron?”
A: Iron is not the Sun’s fuel. Solar energy comes primarily from neutron repulsion in the Sun’s compact, energetic neutron core. The model of an H-filled sun claims solar energy comes from reaction (a):
(a) H-fusion: 4 H => He + 7 MeV per nucleon
Rx (a) is actually step (d) in the series of nuclear reactions that produce solar energy (SE), solar neutrinos and solar wind H in exactly the proportions observed:
(b) Neutron emission: => n + 12 MeV per nucleon (60% SE)
(c) Neutron decay: n => H + 1 MeV per nucleon (5% SE)
(d) H-fusion: 4 H => He + 7 MeV per nucleon (35% SE)
(e) H-escape: 3 x 10^43 H => Departs each year in the solar wind (100% SW H)
(f) Net: 4 => He + 20 MeV per nucleon (100% SE, 100% solar neutrinos)
Each excited neutron in the solar core has ~ 3 times (1/0.35) the amount of energy that is available from H. The real Sun’s lifespan will be ~3 times longer than that of an H-filled Sun.
Q: 2) “Iron does not fuse without absorbing energy to do so. What is the main source of energy if not hydrogen?”
A: Repulsive forces between neutrons. See these overheads of a talk presented in Dubna, Russia: http://www.omatumr.com/Overheads/Overheads.htm or see the published paper: http://arxiv.org/pdf/astro-ph/0609509v3
Q: 3) “Does an iron content alter our understanding of the mass of the sun?”
A: No.
Q: 4) “Why would the sun be iron rich when the most abundant element in the universe is hydrogen?”
Answers: What occupies the most space is not necessarily the most abundant. What astronomers don’t see may be more abundant than what they “see”.
a.) In a weak gravitational field a free neutron decays in about 10 min, n => H
b.) In a strong gravitational field, the process is reversed, H => n
Light is emitted when atomic electrons lose energy. The neutron has no atomic electrons. Hence astronomers “see” Hydrogen (H), not the neutron (n).
c.) In neutron decay, invisible matter becomes visible.
d.) In neutron decay, n => H, V(H) = 1,000,000,000,000,000 V(n)
[The volume occupied by a Hydrogen atom is ~ 1,000,000,000,000,000 x the volume occupied by a neutron.]
Q: 5) “What kind of spect(r)al emissions would we expect from an iron sun? Would they be different from a hydrogen sun?”
A: Exactly what is observed coming from the Sun, without cheating the observations with claims that 65% of the solar neutrinos magically oscillate away.
With kind regards,
Oliver K. Manuel
Former NASA PI for Apollo
Oliver K Manuel,
Thanks for your reply. You say “The real Sun’s lifespan will be ~3 times longer than that of an H-filled Sun.”
I have read that scientitst believe that the sun will become too hot to support life perhaps as early as +1billion years, long before it becomes a red giant. In connection with your previous statement, what are your thoughts on the habitable time remaining on planet earth?
RB (09:08:12) :
DirkH,
When you say
But the existing GCMs are tuned to incorporate assumed positive feedbacks, otherwise they would not produce alarming results. They are inherently unstable by design. For such a system, the initial conditions lead to ever-amplifying oscillations or a push over the brink straight ahead,
this is a statement without any foundation. It implies a lack of good understanding of positive feedback with regards to implications for unbounded growth. Unless appropriate conditions are met, positive feedback results in damped oscillations, not ever-amplifying oscillations. This is a meme that is frequently and erroneously circulated on the web, I see no evidence in your statements that yours was not along the same lines.
Well, in that case they are not feedbacks.
“Well, in that case they are not feedbacks.”
I’m sorry, I don’t understand your statement.
Paul Vaughan (02:34:29) : Questions:
1) Are you using monthly data? using annualized means
2) Are these r^2 values for the 5 year moving average? No annualized means for both temp and PDO+AMO+”sunspot integral” without any further smoothing
Here’s what Wikipedia says:
A positive feedback does not necessarily lead to exponential runaway. Consider a time lag involved, and a system that is disturbed by a needle impulse. Let the positive feedback have a gain smaller than 1. You will see echoes of the input impulse getting ever more faint. After an infinite time the system returns to a 0 output, all the echoes having gone.
That being said, this is not the situation with the GCM’s. They are assumed to be perturbed constantly, in only one direction, positive feedback is assumed : higher temperatures are assumed to lead to higher humidity and release of more CO2 and this leads to even higher temperatures. I see this as a description of a classic exponential runaway and all the utterances of the “credible climatologists” of the James Hansen school of thought are designed to give this impression. After all, this is what sells books.
I don’t understand what the climate modelers don’t understand. It seems to me that they are proceeding on a false assumption:
The theory of global warming, and the climate models that support it, are predicated upon the assumption that the sum of the positive feedbacks can exceed the sum of the negative feedbacks. This isn’t right. As Einstein might have quipped, this isn’t even wrong. This is a gross violation of everything we have learned about physics for hundreds of years. This contradicts principles of physics that were laid down by generations of scientists stretching all the way back to Newton, Archimedes and even Aristotle. This is the very essence of the myth of perpetual motion.
The planet as a system has a certain amount of energy being fed into it. Being a highly complex system, various fluctuations in various systems occur over the short term. In the long term however, the amount of energy fed into the system, equals exactly the amount of energy radiated out. It may take a month or a trillion years, but that’s the number. That’s not an estimate or an approximation. The sum is exactly zero. A greenhouse layer can cause a short term increase in the amount of energy retained. In the long term, the amount of energy going into the system must equal exactly the amount of energy coming out. Either that or entropy doesn’t work and perpetual motion does. The negative feedbacks must exactly equal the positive feedbacks in the long term and any theory or model that presumes otherwise has a built in error.
If the climate is highly sensitive, then the negative feedbacks must appear as quickly as the positive and cool any warming shortly after it appears. If the climate is highly insensitive, then the warming of the last 180 years cannot be due to CO2 increases that began 90 years ago, and will be cancelled by negative feedbacks that were initiated equally long ago. No amount of torturing the data can change this, and I challenge anyone with credentials in physics, thermodynamics, or similar to publicly put their credentials on the line and say I am wrong. The results as analysed by Dr Spencer suggest I am right.
Roger Knights,
Just because it says so in Wikipedia doesn’t make it right. Why don’t you also see what Wikipedia says about, say, the Barkhausen Criterion? The positive feedback in climate models raises the sensitivity of CO2 from a no-feedback case of about 1.2C per doubling to a most likely value of 3C per doubling, indeed with high temperatures leading to more water vapor etc.
I see this as a description of a classic exponential runaway
No, it does not imply that, just a bounded amplification over a no-feedback case. Greenhouse effect theory quite strongly says that there is no significant chance of a runaway Venus effect on earth, and that is the consensus view if you will.
I’m not sure what I said was objectionable, but to Roger Knights:
Just because it says so in Wikipedia doesn’t make it right. Please check what Wikipedia says about the Barkhausen Criterion?
davidmhoffer (11:38:25) :
see:
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
(n.b. there was a weak rebuttal to this published and then a rebuttal to the rebuttal published)
James Hansen’s own modeling work at NASA also shows that global warming has natural causes and is not due to anthropogenic CO2. See this examination of Hansen’s modeling: Hansen Model
Mark Sawusch (12:02:37) :
see:
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
AAAAAAAAAAAAAAAGH!
You mean I wasn’t FIRST? Gnashing of teeth, wringing of hands, dreams of a nobel prize laureate for original work rapidly fading…
OK, was I at least first on WUWT? Because that;s the only forum the nobel committee should consider, and that paper would then be relegated to a reference I could site as supporting my original work?
“davidmhoffer (12:36:04) :
[..]
OK, was I at least first on WUWT?”
No 😉 search for Gehrlich in the search box and you’ll get many WUWT hits.
“RB (11:46:27) :
I see this as a description of a classic exponential runaway
No, it does not imply that”
Driving over freezing roads on a sludge of water, snow and ice i had time to ponder it (exactly the right situation to ponder global warming). You are right; the gain could be smaller than one or change nonlinearly (probably) so we can’t say without running the models. We could end up with +20 deg C anomaly and stay stuck there (assuming that the AGW theory is right).
Thanks for your persistence 🙂
Which makes me wonder what would happen
davidmhoffer (12:36:04) :
well how about kudos for recognizing this on your own?
BTW I asked Gavin Schmidt of NASA/GISS to provide scientific criticisms of this paper on spielclimate.org – I mean realclimate.org – and all he could come up with is that it is “rubbish”