Comments on Hansen et al 2005: "the Smoking Gun"

In the absence of timely technical support to fix our database issue, I thought I’d just a link to another site commenting on the recent paper by James Hansen, Gavin Schmidt et al purporting to show a smoking gun of "an imbalance between solar radiation and atmospheric emission"

Luboà…⟠Motl : http://motls.blogspot.com/2005/04/earths-energy-balance.html

If anyone knows of others, send an e-mail or post a comment.


25 Comments

  1. Roger Bell
    Posted May 1, 2005 at 8:29 AM | Permalink

    Three points.
    Firstly, please read Dr Motls remarks. In particular, click on the cargo cult link. It takes you to a talk by Feynman, who makes the point that a report on an experiment should say everything that might make that experiment invalid – you have to put down all the facts that disagree. Hansen & company should read that.
    Secondly, as Tennyson has just remarked to me by email and also says in his paper with Maurellis ” There is a fudge factor put into the models to mop up extra atmospheric absorption which cannot be properly accounted for by known absorptions. The actual functional form used is of very dubious provenance.”
    I don’t know of any mechanism whereby the sun’s luminosity can change over short periods of time, but the Maunder minimum (lack of sunspots) does coincide with the Little Ice Age and didn’t the Chinese see lots of sun spots around the Medieval Warm Period? All this delicate balance of absorption and emission by the earth’s atmosphere and surface indicates, to me at least, that a tiny change in the Sun’s energy output could easily cause ice ages or warm periods.
    Thirdly, if people login the http://www.telegraph.co.uk, they can read an article about “Journals censoring global warming debate” The journal Science doesn’t come out of it very well if I apply the Feynman test.
    Thank you, Steve et al, for setting up this site

  2. John A
    Posted May 1, 2005 at 9:29 AM | Permalink

    re: #1

    I don’t know of any mechanism whereby the sun’s luminosity can change over short periods of time

    Actually I do. It’s called the solar cycle. Although I’m in an Internet café and can’t locate the exact reference, there was a paper published not long ago showing that the warming and cooling of the 20th Century followed rather slavishly the changes in the length of the solar cycle. (I’m sure that someone here can give the exact reference)

  3. Steve McIntyre
    Posted May 1, 2005 at 10:47 AM | Permalink

    Dear Roger, Can you post up some infor on Tennyson’s comments. He’s very authoritative. I’ll put up Arking’s comments later on a NIR water vapor query later today. Regards, Steve

  4. Phil B.
    Posted May 1, 2005 at 11:35 AM | Permalink

    re: #2, John A., I think that the chart you are referring to is located here http://www.astro.phys.ethz.ch/research/fligge/paleo_fig3_nf.html, which includes the reference paper details. I haven’t read the reference paper, so not sure of the pedigree of the chart.

  5. Roger Bell
    Posted May 1, 2005 at 11:54 AM | Permalink

    Steve,
    Would you mind sending your email address to me at
    roger@astro.umd.edu and I’ll email you the text of the message I sent to Tennyson and his reply? It’s a bit long for me to re-type it. I’ll keep your address confidential.
    Please give my regards to Ross McKitrick.
    Roger

  6. brent
    Posted May 1, 2005 at 12:54 PM | Permalink

    Leading scientific journals ‘are censoring debate on global warming’

    http://tinyurl.com/djanf

    Here’s the telegraph article direct link

  7. John G. Bell
    Posted May 1, 2005 at 1:46 PM | Permalink

    Roger, see “The Global Warming Debate” By James Hansen.

    http://equake.geol.vt.edu/acourses/3114/00Climate/gwdebate.html

    Hansen likes to quote Feynman.

  8. Michael Mayson
    Posted May 1, 2005 at 3:20 PM | Permalink

    Re #2. John, here is an updated paper (1998) on the correlation between solar irradiance and global temperature

    http://www.astro.phys.ethz.ch/papers/fligge/GL264W01.pdf

  9. John G. Bell
    Posted May 1, 2005 at 5:05 PM | Permalink

    Steve, with the tree ring data fixed up as best you can, it might be fun to see if you can find evidence of the known solar cycles in them. There are at least three. The one we know and love is 11 years long. The longest is 83 years. The mid one is 20 years. If you can’t even find the 11 year cycle, that might be interesting.

    Also solar related, from the NASA news archive “NASA Study Finds Increasing Solar Trend That Can Change Climate” March 20, 2003

    http://earthobservatory.nasa.gov/Newsroom/NasaNews/2003/2003032011367.html The sun’s historic irradiance, say past 2000 years, is an area of active research.

    Roger, the Maunder Minimum was strange. No sun spots in the cycle normally equates to high energy output. Not so then! That is one of the reasons why I wonder.

  10. Roger Bell
    Posted May 2, 2005 at 3:38 PM | Permalink

    John G.
    I asked Allen Sweigart, who does stellar interior calculations, if he knew anything about the Maunder minimum. The only paper he knew of is Bhatnagar et al A&SS 281,761, 2002, who found that the total solar irradiance decreased by 0.19% during the minimum. I’m asking someone else, who is interested in possible variations in the solar radius.

  11. Ferdinand Engelbeen
    Posted May 3, 2005 at 3:56 AM | Permalink

    John,

    There is some evidence of 11/22 year solar cycles in tree rings, probably indirect, as result of changes in rain patterns due to changes in jet stream position as result of the sun cycle. Longer cycles of climate can be seen as 14C changes (which amount is influenced by solar magnetic field) incorporated in the fixed CO2 of the trees. Again, this may result in changes both of temperature and humidity.

    The main change during a sun cycle is the influence on cloud cover. While the cosmic ray/cloud cover link is uncertain, there is a measured change in cloud cover of 2% over a sun cycle, which reinforces the relative small impact of direct insolation changes. See for the influence on different geographical levels:
    Global: http://folk.uio.no/jegill/papers/2002GL015646.pdf
    USA: http://www.gsfc.nasa.gov/topstory/20010712cloudcover.html
    For Boston: http://www.erh.noaa.gov/box/effects.htm

    For the global oceans, the SST (sea surface temperature) changes with app. 0.1 K during a sun cycle. In the tropics, this can go up to 0.5 K within a few years from before the sun’s maximum to the maximum…

  12. Posted May 3, 2005 at 7:50 AM | Permalink

    Roy Spencer has a skeptical, but rather friendly analysis of Hansen et al. at http://techcentralstation.com/050305C.html.

    Gavin Schmidt defends the article of his team at http://www.realclimate.org/index.php?p=148.

  13. Peter Hearnden
    Posted May 3, 2005 at 12:25 PM | Permalink

    Re #12. Actually, I quite enjoyed reading Dr Spencer’s comments. Why? Well, I don’t agree with him, but I didn’t feel my views being riduculed, my intelligence doubted, my motives and honesty questioned. Rather he put his case (‘wait and see how bad it is’ – yep, and if it is bad?) and left it at that. All very unlike how TCS usually is, but the second such article by Dr Spencer. I approve :). Of course, he didn’t get involved in a debate – that’s what fires up people I suppose…

  14. John A
    Posted May 3, 2005 at 3:52 PM | Permalink

    Ferdinand,

    How much does 2% cloud cover make to the radiative balance?

  15. John G. Bell
    Posted May 3, 2005 at 8:27 PM | Permalink

    Roger, thank you. I got a copy from http://www.prl.ernet.in/~sushant/space_sci.ps.gz
    Ferdinand, thank you for the links.

  16. John Davis
    Posted May 4, 2005 at 5:11 AM | Permalink

    I was amused to see Gavin Schmidt write “… and has been described as the ‘smoking gun’ for anthropogenic climate change…” on realclimate. The quote is from James Hansen in their own press release.
    I’d say that IF they’ve got their ocean mesurements (and physics) right then they’ve absolutely proved that the oceans have got warmer, that something must have caused it, and that the something is equivalent to the stated radiative imbalance. Their model presents a good educated guess as to wht the something might be but is in no way a proof. It’s all very interesting but I’m not at all sure it has much of a bearing on the future of the human race.

  17. Steve McIntyre
    Posted May 4, 2005 at 5:59 AM | Permalink

    The ocean is very opaque to infrared and NIR radiation so any CO2-affected radiation will be absorbed in about the first cm of the ocean. On the other hand, blue light can penetrate a number of meters (and further than red light). I’ve seen some interesting articles on this, but don’t recall the references off hand. There’s been some publicity from time to time that solar UV radiation is much more volatile than solar output as a whole. I don’t know whether there might be some additional volatility in the blue light portion of the spectrum relative to the total spectrum. For the small wm-2 involved, maybe there’s enough volatilty. There’s a lot of evidence that solar output in the 20th century has been relatively high. It strikes me that you need to penetrate more than part of a cm to warm the ocean and that maybe blue light is involved. Just a thought. Steve

  18. Dave Dardinger
    Posted May 4, 2005 at 11:01 AM | Permalink

    Does anyone know if the additional material for the paper has a breakout as to what part of the .85 w/sq. m is at what depth? It looks to me from the drawing that it’s most all in the top 100 meters or so. If that’s the case then it’d be a lot easier for the heat to be released again in a short period of time.

  19. Michael Mayson
    Posted May 4, 2005 at 7:33 PM | Permalink

    Re #17: Since “The ocean is very opaque to infrared and NIR radiation” can anyone explain the physics of ocean warming?

  20. Ferdinand Engelbeen
    Posted May 5, 2005 at 12:07 PM | Permalink

    Re #14,
    Difficult to say. Depends of where the main difference is. In general, low altitude clouds, which have a good correlation to the solar cycle, have a cooling effect. More solar intensity leads to less clouds, thus more warming. From the radiation balance, clouds reflect some 100 W/m2 back to space, thus 2% would be some 2 W/m2 all over the surface. But that is not the whole story, as clouds also reflect IR from the surface back to earth (see the smaller difference in temperature between day and night with cloudy skies). And the altitude (tropics, subtropics, moderate, polar) also makes a lot of difference in heat balance. All together, the solar cycle is mostly visible in the tropics (on sea surface temperatures), where it is in the order of several W/m2, it is smaller and opposite in the US (more clouds and precipitation), reverse in China (less clouds and warmer),… Thus one need detailed weather/climate trends over the whole earth to see the overall picture. In average, the temperature variation over the oceans’surface is 0.1 K during a sun cycle. That needs a difference of several W/m2 for such a change in a short time…

    Re #17
    UV has a variation of 10% over a sun cycle, against 1% for the whole solar output. It has it’s largest influence in the stratosphere, where the difference is app. 1 K over a solar cycle. This induces a shift in planetary waves and hence the position of the jet stream with a lot of regional (and global) consequences. IR indeed is absorbed in the upper layer of the oceans (the “skin”), while other waves penetrate farther, depending of the wave length. While most of the upper 100 m is rather well mixed, the skin and overlying air temperature can have different trends over a day cycle. See: http://www.asp.ucar.edu/colloquium/2001/curry01.pdf
    What this means for an increased GHG effect (more IR absorbed at the skin – higher temperatures – faster convection – less clouds – more loss of IR to space…) remains to be seen.
    Some addtional reading which may be of interest about the radiation imbalance in the tropics:
    http://www.atmos.ucla.edu/csrl/publications/pub_exchange/Wielicki_et_al_2002 and

    http://pubs.giss.nasa.gov/docs/2002/2002_ChenCarlsonD.pdf

    Re #18
    The depth/latitude trend in ocean heat trends can be found from Levitus 2005: http://www.nodc.noaa.gov/OC5/PDF/PAPERS/grlheat05.pdf figure 2. The interesting point is that most of the heat content increase is near the surface mostly in the tropics in the 30N-30S band and to lower depths in the 30S-50S band.
    Levitus has some interesting comment:
    “However, the large decrease in ocean heat content starting around 1980 suggests that internal variability of the Earth system significantly affects Earth’s heat balance on decadal time-scales.”
    Remarkable that Hansen e.a. start their comparison of ocean heat content and model estimates in… 1993.

  21. Ferdinand Engelbeen
    Posted May 5, 2005 at 12:47 PM | Permalink

    Re #19
    The depth/colour absorption can be found at: http://maritime.haifa.ac.il/departm/lessons/ocean/lect13.htm but is also influenced by plankton growth (more absorption of blue at lower depts). The solar energy bound to each wavelength can be found at http://sd.znet.com/~schester/facts/solar_energy.html. Thus the absorption is in the full depth of each wavelength x the energy of the same wavelength. Most energy is absorbed in the upper 100 m, and the upper 300 m is rather well mixed. The interesting part is in the skin layer, where all IR is absorbed and temperature differences/evaporation can be induced independent of the upper ocean temperature…

  22. Dave Dardinger
    Posted May 5, 2005 at 1:33 PM | Permalink

    Concerning #20 re #18

    Thanks for the link. The most interesting thing I noticed in that paper is figure S2, showing the linear trend and this then revealing what could easily be a 22 year cycle suggesting a solar influence. Since the linear trend looks pretty steady, the next question is if it goes back much further or not? I don’t know if there’s enough accurate data to see if it goes back to the end of the 1800s or not. If so, it probably doesn’t have much to do with CO2. If the 1955 onward data shows a real linear trend, however, it also is rather iffy for AGW as opposed to natural trends.

  23. Ferdinand Engelbeen
    Posted May 6, 2005 at 1:23 AM | Permalink

    Dave,
    The ocean heat content figures don’t go back that far, as there were ample measurements of the deep(er) oceans before 1955. But ocean surface temperatures go farther back. Although only an approximate for heat content, and the doubts one can have of the accuracy in earlier times, these show two linear increases (1905-1945 and 1975-2000), comparable to what is seen in land based temperature trends, see: http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif of the CRU (climate research unit, UK). The first upswing anyway is natural, the second is said to be mostly by GHG’s, but IMHO is mostly natural too. My opinion is based on the fact that in the past 70 years, solar activity is higher than in any similar period of the past millenium and even the past 8,000 years, see: http://cc.oulu.fi/~usoskin/personal/Sola2-PRL_published.pdf and http://www.newscientist.com/article.ns?id=dn6591
    Current climate models quite certainly underestimate solar influences, as they only include the variation of solar energy directly reaching the earth’s surface. They don’t include secondary effects of solar variations on cloud cover, jet stream position,… which strengthen the direct effect with a factor 2 and more…

  24. John G. Bell
    Posted May 9, 2005 at 11:34 AM | Permalink

    Roger, Could be de Garidel-Thoron et al Nature 433,294, 2005 provides us with the data to nail down the Milankovitich contributions via 1.75 million years of high resolution sea surface temperatures of the western Pacific warm pool. Some of what is left over might be solar irradiance changes. Would Allen Sweigart find anything of use in this?

  25. John G. Bell
    Posted May 16, 2005 at 6:16 PM | Permalink

    Re #24 Obviously I meant the impact of the Milankovich contributions. The Milankovich contributions are known which is the whole point. Why the tilt of the Earth’s axis was
    key before 850 kyr ago, and the eccentricity of the orbit more important from then on I
    can’t figure. Perhaps the drift of the south pole away from the Antarctic coast and
    toward the center of the continent in this time had an impact? A huge sheet of ice might
    remain fixed next to the Antartic polar coast at low tilt? Melt away at high season
    inducing tilts? When the pole moved to the Antartic interior it was no longer viable?

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