I really wish Gavin would put as much effort into getting the oddities with the GISTEMP dataset fixed rather than writing coffee table books and trying new models to show the sun has little impact.
This paper gets extra points for using the word “robust”. – Anthony
Solar trends and global warming (PDF here)
R. E. Benestad
Climate Division, Norwegian Meteorological Institute, Oslo, Norway
G. A. Schmidt
NASA Goddard Institute for Space Studies, New York, New York, USA
We use a suite of global climate model simulations for the 20th century to assess the contribution of solar forcing to the past trends in the global mean temperature. In particular, we examine how robust different published methodologies are at detecting and attributing solar-related climate change in the presence of intrinsic climate variability and multiple forcings.
We demonstrate that naive application of linear analytical methods such as regression gives nonrobust results. We also demonstrate that the methodologies used by Scafetta and West (2005, 2006a, 2006b, 2007, 2008) are not robust to
these same factors and that their error bars are significantly larger than reported. Our analysis shows that the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980.
Received 17 December 2008; accepted 13 May 2009; published 21 July 2009.
Citation: Benestad, R. E., and G. A. Schmidt (2009), Solar trends and
global warming, J. Geophys. Res., 114, D14101,
doi:10.1029/2008JD011639.
hat tip to Leif Svalgaard
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Can we say that Gavin’s credibility is nonrobust?
I look at Gavin’s graph and note that solar influences started out below zero at the earliest part of his graph…. It then rises to be above zero at the latest end of his graph…. I look at the temp trends… They start out lower at the start of his graph and finish higher at the end of his graph…
Seems unequivocal to me…. Solar has a definite influence on Global temps.
…. Gavin just showed it:-)
I’m severely unimpressed with this offering from Gavin. A computer modeling based study using disputed temperature data and disputed TSI data claiming to rule out solar influence on climate. At best I would only consider TSI to be a proxy for solar influence, and I am very wary of revisionist reconstructions of TSI fluctuation. I believe Jack Eddy was correct when he said that there would be “many plugs” connecting the sun to our climate.
Referring to questionable TSI reconstructions alone concerning solar influence smells like a Straw man argument. I am starting to suspect that black body TSI measurements using cavity sensors on satellites is only part of the picture. Leif has pointed out in a previous thread that the atmosphere is largely transparent to microwave frequencies. Planet Earth has a lot of water…
This is a follow up to my previous post (response to RW (16:34:16) 🙂
RW writes
The combination of these three effects accounts for the observed warming.
meaning that an increase in solar (1), lack of volcanic activity (2) and increase in C02 concentrations (3) combined to produce a warming trend of ~0.14 deg per decade between 1915-1944 (GISS temperatue record). [Note that the GISS record has a warming trend of ~0.16 deg per decade since 1975].
Using RW’s figures, the CO2 forcing (3) between 1905 and 1940 is only about ~0.25 w/m2 which is negligible. But even that is not relevant, because when the warming actually started, i.e. between 1910 and 1920, CO2 concentrations would have been even lower.
As Gavin Schmidt himself states the solar (1) contribution was tiny – and, according to Leif , it’s actually even tinier than Gavin’s estimate.
That just leaves volcanic activity (2) – or the lack of it to be more precise. According to James Hansen’s volcanic aerosol forcings diagram, there was a major eruption in the early 1880s which I assume to be Krakatoa and another one in the early 1900s which I think might be the Guatemalan eruption in 1902 (but I’m happy to be corrected on that). The ‘lull’ in activity, therefore, was no more than 15 years before the warming started.
I think RW is right on this, i.e. these are the accepted contributory factors for the early 20th century warming by the AGW crowd. From this we can draw the following 2 conclusions:
1. The Hockey-Stick cannot possibly be correct and, if that sounds obvious to most, it’s not yet obvious to everyone. The H-S reconstruction shows a sharp upward kink in ~1902. This represents a climatic shift which is completely out of character with the previous 900 years – yet all that’s happened is there are fewer volcanos. For the H-S to be correct , we have to believe that there were no periods in the past 1000 years (2000 years if we accept Mann & Jones) where volcanic activity was as low as in the early 20th century.
2. The AGWers have no idea what was responsible for the early 20th century warming (or the subsequent mid-20th century cooling) and, therefore, cannot possibly explain the late 20th century warming. The “detection and attribution” studies from which they conclude that it is only by including ghgs that 20th century warming can be explained are based on flawed assumptions. In a recent RC post, Raypierre acknowledged the ‘ocean’ effect’. There is some backpedalling going on – but it’s nothing to do with the sun.
Gavin et al will attack on the solar front because it’s where they can win. The more that sceptics promote the sun as the driver the happier they’ll be. The sun/climate link is patchy at best. I doubt very much that there will be any significant cooling due to solar activity – and certainly none in the near future.
There are plenty of weaknesses in the ‘catastrophic AGW’ argument (CO2 is likely to cause some warming) but the sun is not one of them.
Jimmy Haigh (20:12:59) :
“… models don’t work and they never have – and the never will – as prediction tools”
because they violate fundamental laws of physics:
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
“It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing their own models. ”
Freeman Dyson
But then I forgot; the Omniscient Hansen says that Dyson doesn’t know what he’s talking about. I wonder which has done the most useful science?
Slightly off-topic, but I have a quote I would like to nominate for quote of the week:
“When we apply full-blown GCMs, the match between hindcasts and observations is nothing short of impressive; ”
From here:
http://tamino.wordpress.com/2009/07/14/warming-interrupted/
Joel Shore:
“Steven Hill says:
How can 330ppm affect anything? It’s like a few grains of sand hidden in a gallon bucket of sand.
I am sure that we could find substances that would kill you at far lower concentrations.”
Phil:
“Nonsense, try reading up on the physics.
Add 330ppm of chromium to corundum (colorless) and you’ve got a ruby add iron instead and you’ve got a sapphire. Still think that a low concentration of an absorber can’t have a noticeable effect?”
—
Why do they have to give us these inane, fatuous, irrelevent analogies? Helps to hide the non-sequiturs, I suppose. Anyway, when I studied it, the stuff Phil talks about was chemistry.
———————
Going back a couple of threads, is this article printed on toilet paper?
Or maybe you could tax Gavin’s output instead?
O/T, and apologies if this has been posted, but I just ran accross this article during my morning cup o’ joe:
http://www.telegraph.co.uk/news/worldnews/asia/china/5877583/Giant-Chinese-dustball-circles-the-Earth.html
This is one condensed instance, so certainly there is some level of this taking place at other times, and it seems this would have to have some impact?
JimB
There was recently a paper published which estimated there is a missing mechanism which amplifies the solar forcing by amplitude of 7. If we amplify the dash solar curve by 7, we get close to GISS record, even the last part should be more flat than GISS presents.
OK, I’ve finished calibrating my “model”.
I have included a lookback to 1850 because it amuses me that Gavin can’t do the same with his model without looking very silly indeed.
I have included a look forward to 2043 on the assumptions that the next three solar cycles are similar to the Dalton Minimum period 1800-1834, and that my assessment of the rate the oceans gain and lose heat is somewhere in the ballpark.
I would welcome questions about my method and any other feedback.
http://s630.photobucket.com/albums/uu21/stroller-2009/?action=view¤t=ssnc-pdo-amo-2043-1.gif
Thanks
I have no desire to read anything from someone who got his clocked cleaned in a debate against a “fiction writer” and 2 “not real” scientists.
Has anyone noticed that arctic ice extent is tracking 2005 values – and has been for some time now.
If it stays that way a major recovery is in progress…
Gavin Schmidt: It’s not the sun, stupid!
Realist: It’s the models, stupid!
Juraj V. (04:02:56) :
There was recently a paper published which estimated there is a missing mechanism which amplifies the solar forcing by amplitude of 7. If we amplify the dash solar curve by 7, we get close to GISS record, even the last part should be more flat than GISS presents.
Try Nir Shaviv’s paper on Using the Ocean as a Calorimeter. It’s on his blog too.
On Wednesday, July 22nd, the Moon eclipsed the midday sun over China. “The temperature dropped from 96.6 F to 88.5F at totality,” http://www.spaceweather.com/
Yup conclusive proof that the sun has no effect on how warm the earth gets.. lmao.
Allan M R MacRae: there is excellent CO2 data from before 1958 from ice cores. I used Law Dome data. Simply saying you think it’s “highly questionable” without any further elucidation is not useful.
“There has been no net warming since 1980 – based on UAH LT”
Incorrect. As my graph already showed, UAH data shows a net warming of 0.37°C – and that is clearly discrepant with the warming seen in the other three datasets, which agrees very closely at 0.46-0.47°C.
To make your incorrect claim, I suspect that you are comparing just two monthly anomalies – one from 1980, one from now. Thus, you are ignoring more than 99% of the data. That is what is known as ‘cherry-picking’, and it’s led you right up the garden path.
Your list of ‘cooling predictions’ contains only pseudo-science and misinterpretations. Landscheidt was an astrologer; Piers Corbyn has made many weather and climate predictions, and analysis of them has shown that they are correct no more often than would be expected by chance. You quote NASA making predictions about the solar cycle – the link you give says nothing about any predictions of ‘global cooling’ so why did you include it? Similarly with Nigel Weiss’s comments. And “Timo Niroma”? A literature search reveals only publications in Energy and Environment, which is not a scientific journal. Doing a proper literature search one finds that not a single serious scientific paper predicts long term global cooling, if CO2 concentrations continue to rise.
George E. Smith: not believing in climate sensitivity at all, wow, that’s a new one. How then do temperatures ever change?
Juraj.V:
“5% increase of much less important GHG than water vapor is negligible”
It seems weird to me that you think you can simply baldly state something like this, with no further justification. You are wrong. A simple calculation shows that the radiative forcing due to this increase in 0.25W/m2. That is sufficient to cause 0.2°C of global warming. By simply looking at the global temperature records, you can see that 0.2°C is not negligible.
“Had not been there two volcanic events in 1984/1991 and natural El Nino, the trend would be flat. Today temperature is on the level of 80ties.”
Analysis which accounts for these effects does not support your statement. There is an upward secular trend. Temperatures today are about 0.4°C warmer than they were in 1980, as you can see if you use all the data instead of just 2 points out of more than 340.
John Finn: “almost constant” is not a fair description. The total forcing from the post-industrial rise in CO2 is ~5.35ln(387/280)=1.7W/m2. 15% of this is not negligible.
Simultaneously you seem not to believe that a lack of volcanic eruptions could cause warming, and that the lack of eruptions since Pinatubo is the cause of all the warming. Have a look at the data. You can see that there were no significant volcanic eruptions between 1912 and 1962. Clearly, a 50 year period with no major volcanic eruptions will be warmer than a 50 year period with three or four.
“Gavin’s just shown there was no increase in solar output.”
That’s funny. I was under the impression that you did not accept this result. Please clarify.
“The combination of these 3 effects before 1940 amounts to diddly squat.”
What a truly bizarre statement. Your position seems to be based on a determination to ignore all the well known, well characterised influences on climate, instead replacing them with a belief that no-one knows anything about why climate changes. Is that the case?
I’d like to offer a little constructive criticism on the graph. It’s really, really boring and could benefit by some decorative touches. Like those found on old maps. Sprinkle some sea monsters and so on around it. The lines are too jaggedy, they should look more like waves with foam and stuff. Ought to have some stuff above the line, like stars, moon, sun. And below the line fishes, and maybe a whale or two. The right side should indicate that’s the end of the known world, and don’t sail beyond it or you will fall off. Oh, and definitely needs a compass rose in the corner so we know which end is North.
Just a few suggestions to make the graph more visually interesting.
Interesting… So we have GISS model E producing sensitivity of 2.7°C used to validate solar against GISTemp. From what I gather in the paper, CO2 forcing is not allowed to vary to produce the best match, it is on or off. A good parallel study would be what CO2 forcing does it take to match UAH + whatever passes as global temp before satellites. Obviously the CO2 sensitivity would be much lower, and solar much higher. The paper states that other temp data sets produce similar results, but how similar, and what data sets? GISS and UAH are so dissimilar now, I don’t see you you could reach remotely similar conclusions. I think you could get similar results by using population as a proxy for CO2, or inverse distance to airports, 1/(number of pirates), whatever.
Once detailed sources and methods are released (any minute now), this would be a great one for Jeff Id and Ryan O to look at.
Curiousgeorge (04:49:10) :
I’d like to offer a little constructive criticism on the graph.
I’m not sure whether you are referring to my graph or Gavins, but anyway, I agree.
It shall be done me hearty, Oi will make it so. :o)
Phil. (20:48:48) : “About 0.09psi if saturated, but not particularly relevant since with no CO2 in the atmosphere not much of the planet would be that warm!”
So are you saying the water vapor isn’t a greenhouse gas?
“right side should indicate that’s the end of the known world, and don’t sail beyond it or you will fall off. ”
“Here there be skeptics”
I think it is great!
They have demonstrated that they can prove the solar forcing (and indeed all the global warming) using multiple linear regressions and a couple of analytical solutions.
Therefore, there is no need anymore for those few hundred million dollars to run numerical solutions on expensive computers. Let’s divert that investment to solar radiation research.
“The solar forcing in these analyses is characterized by the total solar irradiance employed to estimate the linear sensitivity of hTi to S”
and it is summarized as S * .7/4
No matter how is the distribution on earth, the impact of tropical albedo, etc. etc. And of course a quick dismiss of the effect of solar variability on cosmic radiation and cloud nuclei generation.
p. 13.
“One example could be galactic cosmic rays….
In these cases the forcing values might be
underestimated …
However, the regression coefficients were similar
for both GCM and observations, and the fact that these additional mechanisms were not present in these GISS ModelE simulations, suggest that processes such as GCR are not important”
It’s not in the model therefore it does not matter.
To contrast all that, a interesting solar temperature chart and a related recent paper
source
A Lagged Warm Event–Like Response to Peaks in Solar Forcing in the Pacific Region Gerald A. Meehl and Julie M. Arblaster
http://tr.im/tuxU
jmc (02:55:30) :
“because they violate fundamental laws of physics:”
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
Thanks for this paper. Have you tried posting it on real Climate? I think it would get through because they may not understand it over there.
Here’s the abstract:
“The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33◦C is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the
assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.”
RW (04:48:18) : “Juraj.V:
“5% increase of much less important GHG than water vapor is negligible”
It seems weird to me that you think you can simply baldly state something like this, with no further justification. You are wrong. A simple calculation shows that the radiative forcing due to this increase in 0.25W/m2. That is sufficient to cause 0.2°C of global warming. ”
Why do you only look at radiative forcing? What about the counter-effect of clouds?