Guest post by Bob Tisdale
IPCC 20th Century Simulations Get a Boost from Outdated Solar Forcings
Or The Sun Also Can’t Explain the Warming in the Early Part of the 20th Century
INTRODUCTION
In two previous posts, AGW Proponents Are Two-Faced When It Comes To Solar Irradiance As A Climate Forcing and Climate Modelers Reproduce Early 20th Century Warming With The Help Of Outdated Solar Forcings, I illustrated the basic errors that arise when GCMs use outdated TSI reconstructions while simulating 20th Century surface air temperatures. The problem results because the obsolete TSI reconstructions assumed that solar cycle minimums varied significantly, but the current understanding is that solar cycle minimums are, in fact, relatively flat. That is, minimum TSI level during the Dalton Minimum is no lower than the minimum TSI levels during late part of the 20th Century. This can be seen in the comparison chart available from Leif Svalgaard of Stanford University, Figure 1. The current understanding of TSI variability is identified as Svalgaard. Note in Figure 1 that the Preminger TSI dataset also does not have the large variation in solar cycle minimums.
This is discussed in Preminger and Walton (2005) “A New Model of Total Solar Irradiance Based on Sunspot Areas”.
http://www.agu.org/pubs/crossref/2005/2005GL022839.shtml
The other datasets with large variations in solar cycle minima are no longer considered valid.
http://s5.tinypic.com/mmuclk.jpg
Figure 1
And there are many more climate studies that use the erroneous TSI datasets, including those employed by the IPCC.
THE IPCC USED “QUESTIONABLE” TSI DATA FOR ITS 20th CENTURY CLIMATE SIMULATIONS IN AR4
In Chapter 2, “Changes in Atmospheric Constituents and in Radiative Forcing”, page 190 (page 62 of 106 of the following pdf file) of the IPCC’s AR4, the IPCC first describes the three assumptions or motivations for the existence of long-term variability in TSI, and in the next paragraph, they state, “Each of the above three assumptions for the existence of a significant long-term irradiance component is now questionable.” Refer to:
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch02.pdf
Then in their Supplementary Materials to Chapter 9, “Understanding and Attributing Climate Change”, the IPCC identifies the TSI reconstructions used by the modelers in their table “S9.1. Models used in chapter 9 to evaluate simulations of 20th century climate change with both anthropogenic and natural forcings and with natural forcings only”.
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9-supp-material.pdf
The IPCC Table S9.1 is shown as Figure 2. And what TSI reconstructions does the IPCC list for the 20th Century Climate Simulations? The ones they consider “questionable”, of course.
http://s5.tinypic.com/aouzpi.jpg
Figure 2
The key to the solar forcings follows.
Even GISS acknowledges the problems with the use of the Lean et al data in the Hansen et al (2007) paper “Climate simulations for 1880-2003 with GISS modelE”. They state, “Lean et al. (2002) call into question the long-term solar irradiance changes, such as those of Lean (2000), which have been used in many climate model studies including our present simulations. The basis for questioning the previously inferred long-term changes is the realization that secular increases in cosmogenic and geomagnetic proxies of solar activity do not necessarily imply equivalent secular trends of solar irradiance.” Following that, GISS goes on to explain the reasons for their continued use of the erroneous TSI data set, “The fact that proxies of solar activity do not necessarily imply long-term irradiance change does not mean that long-term solar irradiance change did not occur.” Refer to:
http://pubs.giss.nasa.gov/docs/2007/2007_Hansen_etal_3.pdf
(Note: The Hansen et al file is 24MB.)
IPCC KEY TO SOLAR FORCINGS AND REFERENCES
The following is the IPCC’s Key to the Solar forcings and references from page SM.9-12 of the Supplement to Chapter 9 of AR4:
####
SOL = solar irradiance
L95: Lean et al. (1995).
L95 (C00): temporally varying solar constant based on Lean et al. (1995) (Crowley, 2000).
L00: Lean (2000).
L02: Lean et al. (2002).
HS: Hoyt and Schatten (1993).
SK: Solanki and Krivova (2003).
####
Data for the two Lean and the Hoyt and Schatten reconstructions are easy to track down. The Lean et al (1995) data is available here:
The Lean (2000) data:
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/solar_variability/lean2000_irradiance.txt
Note that there is a dataset included in Lean (2000) in which the minimums do not vary significantly. It is listed in the second column and identified as “11yrCYCLE”.
The Hoyt and Schatten (1993) data is part of the TSI reconstruction and composite comparison by Leif Svalgaard. It’s available in .xls format here, listed as Hoyt:
http://www.leif.org/research/TSI%20(Reconstructions).xls
The Crowley (2000) paper listed in the IPCC references is “Causes of climate change over the past 1000 years.”
http://www.sciencemag.org/cgi/content/abstract/289/5477/270
Crowley (2000) refers to a version of the Lean et al (1995) data: “An updated version of a reconstruction by Lean et al. (5) that spans the interval 1610-1998 was used to evaluate this mechanism.” The 1995 and 2000 versions of the Lean reconstruction are part of this post, and since I’ll be looking primarily at the effect of the data from 1900 to 1940, how Lean Crowley updated the last few years of data is not pertinent.
The Solanki and Krivova (2003) paper referenced by the IPCC is “Can solar variability explain global warming since 1970?”
http://www.mps.mpg.de/homes/natalie/PAPERS/warming.pdf
The data from Solanki and Krivova (2003) is difficult to find online (or I haven’t yet found it yet). The Solanki and Krivova (2003) data, however, is described by the National Center for Scientific Research (France) as, “The basic solar constant time series for the 20th Century simulations is constructed by Solanki and Krivova (2003). This data set is characterised by a 2-3 W/m2 increase in solar constant since the Maunder minimum. In the period 1850-2003 most of the total rise of about 1.5 W/m2 takes place in the period 1900-1950. Furthermore the solar cycle (and the variations therein over time) is included. The Solanki and Krivova (2003) time series is very similar to Lean (2000) but with some minor differences, mainly pre 20th century.”
http://www.cnrm.meteo.fr/ensembles/public/data/Descriptionsolar.doc
Again, I’ll be illustrating the effect of the erroneous data on the first part of the 20th Century, so any “pre 20th century” differences don’t come into play.
ADDITIONAL COMPARISONS OF TSI DATA USED BY THE IPCC
Figure 3 is a graph of the current understanding of the long-term variations in TSI, represented by the Svalgaard data (purple). Also included are the reconstructions of Hoyt and Schatten (green), Lean et al 1995 (blue), and Lean 2000 (red). The data begins in 1851.5 and runs the length of the individual datasets. The two Lean datasets and the Hoyt and Schatten data are available through the above links. The Svalgaard TSI data is also included in the linked spreadsheet from Leif.org. It’s referred to as the Leif data in Column C.
Note how sharply the Hoyt and Schatten (green) data rises from 1890 to 1950, but the current understanding of TSI variability is that there was no rise in the solar cycle minimums as illustrated by the Svalgaard (purple) curve. The two Lean datasets also have a significant rise from 1900 to 1960. I’ve “normalized” the Lean 1995 (blue) data in Figure 3 by subtracting 1.1 watts/meter^2 to show that it does follow the same general curve as the Lean 2000 data, with some minor differences, until SC20.
http://s5.tinypic.com/fp6qyp.jpg
Figure 3
AND WHAT EFFECT DOES THIS HAVE ON THE IPCC GCMs?
Assume for example that the GCMs are set to reflect the currently accepted climate sensitivity for variations in TSI, so that the minimum-to-maximum variation in the past three solar cycles results in a 0.1 deg C change in global temperature anomaly. If the solar cycle amplitude for those three cycles is approximately 1 watt/meter^2, then the scaling factor is 0.1. So in Figure 4, the TSI datasets have been scaled by that amount.
http://s5.tinypic.com/2mg6rll.jpg
Figure 4
The Hoyt and Schatten data would reflect a global temperature rise of approximately 0.3 deg C from 1890 to 1940, and that’s a significant portion of the actual rise in global temperature anomaly for the same period. The effect is the same for both Lean et al datasets, but to a lesser extent. But keep in mind, the rise in TSI minimums from the late 1800s to the mid-1900s does not exist. Refer again to the Svalgaard data.
And to refresh your memory on just how much global temperatures rose during the first part of the 20th Century, Figure 5 is a graph of HadCRUT3GL data from January 1850 to December 2007.
http://s5.tinypic.com/296kpdz.jpg
Figure 5
AND A LOOK AT TRENDS FROM 1900 TO 1940
Figure 6 compares trends in the scaled TSI data of the Svalgaard dataset from 1900 to 1940 to the trends of the three other TSI datasets. Again, the datasets have been scaled by a factor of 0.1 to reflect the impact of TSI on global temperatures. Due the variations in the solar cycle maximums, there is a slight trend in the Svalgaard data of ~0.009 deg C/decade from 1900 to 1940. The trend due to the incorrect variations in solar cycle minimums, on the other hand, for the Lean 2000 data is approximately ~0.026 deg C/decade, and for the Lean et al 1995 data, it’s ~0.027 deg C/decade. Then there’s the Hoyt and Schatten data with a trend from 1900 to 1940 of ~0.056 deg C/decade.
http://s5.tinypic.com/t7bknm.jpg
Figure 6
CLOSING COMMENT
As noted in past posts and in blog comments on this subject, if the natural climate forcings used to recreate the temperature rise in the first part of the 20th Century are erroneous, then the anthropogenic forcings used to recreate the global temperature variations in the latter part should not be assumed to be correct.
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Michael D Smith has an interesting comment over at the Landscheidt blog, pointing out that since the Earth is orbiting the SSB and not the Sun there will be an additional variation to that caused by the ecliptic orbit (adding a little to what he said) It just happens that around 1880, 1940 and 2000 Jupiter and Saturn line up at the other side of the Sun (seen for earth) around mid summer, pulling the Earth a little closer to the Sun increasing the northern summer insolation (which to my understanding is quite important for exiting glacials)
John Finn: You wrote, “Whenever I’ve argued the very point that Bob T makes on AGW blogs they’ve moved the goalposts. Tamino now suggests “lack of volcanic activity” as a major reason for early 20th century warming.”
As you know, we had two significant volcanic eruptions at the end of the 20th Century, too. Take the Sato index of stratospheric aerosol optical depth from 1900 to 1999, invert it, scale it so that Mount Pinatubo results in a 0.35 deg C drop in global temperature in 1991, and then throw on a linear trend line. The trend is negative over the 20th century.
http://s5.tinypic.com/sgjvjm.jpg
If we limit the data to the period of 1900 to 1939, the trend turns positive, but it’s only 0.009 deg C/decade.
http://s5.tinypic.com/rhl9q9.jpg
In my reply to Alan S Blue above, I noted that I had written another post on for my blog titled “Reproducing Global Temperature Anomalies with Natural Forcings.”
http://bobtisdale.blogspot.com/2009/01/reproducing-global-temperature.html
The following link is to a gif from that post (Figure 7). It compares the reproduction with solar added to the reproduction with both solar and volcanic aerosols added. In it you can see that volcanic aerosols impacted global temperatures at both the beginning and end of the data, which would keep the effect of volcanic aerosols on long-term trends to a minimum.
http://i39.tinypic.com/w7fz7k.jpg
Steve Hempell: You wrote, “So is this why many AGW supporters websites (and the IPCC, I think) state that in the early part of the 20th century the sun had more of an influence on temperatures than the in the latter part of the century?”
And that’s precisely why the secondary title to the thread reads, “Or The Sun Also Can’t Explain the Warming in the Early Part of the 20th Century”.
Regards
I trust the work and opinion of Leif Svalgaard. The IPCC AR4 LOSU for solar irradiance is ‘low.’ Smaller changes in the Sun could mean the climate is more sensitive to solar factors, not less? The questions remain how does the Sun influence climate, and how much? Shaviv’s recent paper provides more evidence of a solar amplifier, that was also mentioned by Lockwood and Frohlich who dismissed it as not being relevant to climate change over the past 20 years, without actually knowing what it is.
Alan S Blue and John Finn: Another way to look at the available data: The following is a graph of HadCRUT3GL global temperature anomaly data versus scaled Sunspot Number as a proxy for TSI and Scaled Sato Index as a proxy for volcanic aerosols.
http://s5.tinypic.com/jszh4g.jpg
Just as solar cannot explain the warming in the second half of the 20th century, solar plus volcanic aerosols cannot explain the warming in the first half.
Aron, You wrote, “An experiment needs to be run in which we perform temperature recording in a smog filled setting versus recording in the cleaner conditions we have had in the last half of the 20th century.”
I believe some studies have been done, but in more recent times. Investigate “brown clouds.” Refer to:
http://www.unep.org/pdf/ABCSummaryFinal.pdf
Those researching brown clouds claim they “have resulted in surface dimming, atmospheric solar heating and soot deposition.” At least, that’s what I get out of it with a quick look. There are a chunk of references at the end of that link.
Regards
Aron said (00:50:47) :
“Does this back up what I said about temperature monitoring in the 19th century? Cities back then had such dense smog from coal and wood fires that sunlight could not have possibly penetrated to ground level as well as it does today. This means their surface temperature monitoring in or near urban environments would have recorded temperatures lower than they should have been.”
I have long made this pont and would make three observations;
1) Firstly the co2 levels that Beck researched from around 1830 were real and were at similar levels to today.
2) The advent of ‘AGW’ closely follows the enactments of Clean air acts around the industrialised world.
3) Co2 levels don’t have too much to do with anything, as this natural temperature variation has occurred throughout our recorded history and are particlarly well documented in the MWP and Roman warm periods.
Can someone give me a large grant to research it all please?
Tonyb
Roger Carr (00:15:35) :
Extrapolating from that, Denis, your Gordon Brown could say he had seen the crash coming and so had this contingency plan in place…
He will, Roger, he will. This is,after all, the man who claimed in Parliament that he’d saved the world.
“A British Government minister Douglas Alexander said a on a TV programme (Question Time) last night that “Climate Change was the vehicle for creating jobs in the recession”.”
Yes, they should create quite a few jobs with Heathrow’s extra runway and other airport expansions and the expansion to the roads networks (although that is an on again – off again deal, depending on which Minister one speaks to.)
Thanks Bob. I’m writing a long article now and that looks right up my alley. Will research it thoroughly before writing.
some of this debate seems strange: The acrim site http://acrim.com/TSI%20Monitoring.htm shows that even this modern data is still argued over, secondly data on their site and graphs show that there is plausibly a decrease in solar activity over the last minimums ie a negative minimum trend line.
acrim data is by no means resolved as different researchers use different parts of the data ie using low variance data sets to explain future temperauture trends as a result of carbon dioxide rather than solar activity.
The acrim site shows discrepencies over even the recent data which is argued over in different papers, also there is an increasing amount of well documented data that correlate solar activty (sunspoot recordss) and temperature time lines with, be and carbon data. These are collected from the poles and are intimately linked to solar activity in the poles.
Lastly the sun is likely to experience larger external variation than the earth is. Isn’t the position of the earths orbit and tilt important too especially at the poles with their thinner atmopshere) solar variation could matter more at the poles.
yours,
Do my eyes deceive me, or this a new SC23 spot I see right now?
Pierre Gosselin (05:01:19) :
Do my eyes deceive me, or this a new SC23 spot I see right now?
The saga continues….welcome to the Jose minimum.
Anthony and Leif, before this disappears among the other comments:
Anthony, thanks for posting this. Your audience is significantly larger than my normal one.
And Leif, thanks for discussing the outcome of your research here at WUWT. Your findings that solar minimums do not vary significantly continue to be overlooked (or avoided) by climate researchers.
lgl (02:12:20) :
since the Earth is orbiting the SSB and not the Sun there will be an additional variation to that caused by the ecliptic orbit
No, the distance between the Sun and the Earth is not influenced by where the barycenter happens to be. We had a long discussion on that a while back. Here is a diagram showing the purported distances to the SSB and the solar radiation [TSI] that should be received [from a paper by Alexander that we have also discussed extensively] http://www.leif.org/research/DavidA10.png and here http://www.leif.org/research/David11.png is a plot of what is actually measured [black curve] with red dots showing the SSB distance TSIs.
Pierre Gosselin (05:01:19) :
Do my eyes deceive me, or this a new SC23 spot I see right now?
Good ole SC24 is still with us [as it should be because of the overlap between cycles. There might be another SC23 spot [or two] in about a weeks time.
Geoff Sharp (00:49:50) :
According to Usoskin and Solanki the last 400 years IS sunspot data taken from (Hoyt & Schatten 1998). 10 year averages would still show the prevailing trend.
Make a plot with both series on the same graph for the last 400 years and ask again.
Frank Miles (04:59:26) :
data on their site and graphs show that there is plausibly a decrease in solar activity over the last minimums ie a negative minimum trend line.
That decrease [mainly seen in the PMOD data] is likely an artifact due to drift of the PMOD instrument. Here is a plot showing the difference between PMOD and SORCE [the latter having a better calibration] http://www.leif.org/research/Diff-PMOD-SORCE.png
When activists demand green jobs they mean government jobs for activists and the most fanatically devoted environmentalists. The plan being that they take over parts of government bureaucracy without ever having the need for parties like The Green Party to be elected. It shows their disdain for democracy and liberty that they want to take over government via the back door and then impose laws and regulations upon us to force us to live the way they want us to live.
If Green jobs meant just the creation of technology related jobs or services to improve home insulation or install solar panels, etc then they could start their own businesses to provide society with those solutions and services instead of demanding that government must do it.
Shows up in the magnetogram.
http://sohowww.nascom.nasa.gov/data/realtime/mdi_mag/512/
A baloon heated with a propane burner demonstrates many things, among others that it goes up with a “hot atmosphere” composed of all the objects of passion of GWrs: CO2, Water. (C3H8+5O2=3CO2+ 4H2O), and if the burner stops…you know what happens.
I am still asking myself how do the GWrs. manage to heat their feet with a bottle filled with CO2 gas instead of being filled with warm and friendly water.
Thanks TonyB
I am beginning to think that our whole temperature reconstruction before satellites is off and needs to be recalculated.
First of all the temperature reconstruction from ice core data is quite low resolution and a localised effect. It provides a very good insight into fluctuations but the reconstruction itself might be a little cooler than actual global temperature averages because ice core data is after all localised and low resolution as I said. I think that global temperatures should be ever so slightly warmer than the ice core record tells us.
Then comes thermometer readings from the 19th century onwards. For the first century these records are too cool because dense smog prevented sunlight from reaching ground level in urban and outlaying areas. The data is also very low resolution for that whole century. Here I think global temperatures should be warmer, almost close to present day readings. In other words, nearly all the recovery from the Little Ice Age happened in the 19th century, not the 20th.
From the mid 20th century until present the smog has cleared up but the Urban Heat Island effect has skewed data. The data becomes higher in resolution (meaning derived from more locations) but according to the Surface Station site most of the stations (marked in orange) are of poor quality (next to roads, runways, air conditioners, on rooftops, on asphalt, etc). This time I think the records should be leveling off from the 19th century warming and show us a mostly flat line.
From the 70s we get satellite data which shows warming mostly as an urban heat island effect with almost nothing going on in the troposphere even though carbon dioxide emissions are increasing at the fastest rate ever. This time I think we should see a little warming, mostly because of the growth of urban areas, but it begins to cool off around the turn of the millennium and then begins to cool to present day conditions.
That’s the basics of how I think a revision will look like. Currently we have a 19th to mid 20th century that looks colder than it should be and thus it seems we have more warming in the 20th century than has occured. Most of the recovery from the Little Ice Age would have thus occurred not long after the Dalton Minimum.
Aron (07:32:00) said
” Thanks TonyB
I am beginning to think that our whole temperature reconstruction before satellites is off and needs to be recalculated.”
Anyone who posts here will have noted my huge scepticism about the concept of global temperatures and the reliabilty of temperatures back to 1850 based on a small number of ever changing unreliable stations, many now set against a backdrop of UHI.
Personally I much prefer National temperature databases and have been collecting them for publication here in the near future. These still need to be treated with a pinch of salt but their individual shortcomings-if any- can be recognised better than some global temperature where lots of datasets have been poured in.
This is Hadley CET back to 1660-unsmmothed and unfiltered..
http://cadenzapress.co.uk/download/menken_hobgoblin.jpg
The enormous temperature variations prior to increased levels of co2 can be readily seen, many of which approach todays even though they are mostly within the LIttle Ice Age. I think it perfectly reasonable to believe that temperatures would have been higher without smog as a sunnier climate is likely to result in greater warmth.
Tonyb
[snip NO MORE DISCUSSIONS OF BARYCENTRISM – Anthony ]
From previous comments, I now see that SOHO’s site is back with the living. That’s a petty good looking little speck, considering how weak the magnetogram’s looking. Saw that the spot was noted by Catania but not yet by the SWPC. In fact it does look to be SC23; just north of the equator and while not really unambiguous, the white is slightly leading the black.
Geoff Sharp (00:52:15) :
Would like to have a read of that Nir Shaviv paper tallbloke, is there a link or perhaps email me?
Drop me an email Geoff.
TonyB,
Gosh, if Hadley CET that you posted was smoothed it would be almost exactly as I proposed above. Thanks for that!