Thursday, September 26, 2013

How climate models dismiss the role of the Sun in climate

The IPCC attributes 20th century global warming primarily to CO2 on the basis climate models, claiming that the increase in solar activity during the 20th century was insufficient to cause the observed warming. Thus, it is claimed, CO2 is by default the only other possible cause of the warming [they don't know how to model ocean oscillations, so those are automatically & conveniently excluded as a cause].

However, climate models are programmed with solar forcing that is 5-13 times less than found by state-of-the-art solar activity reconstructions. For example, the NASA-GISS climate model uses the following solar forcing assumption:

which shows solar activity increased during the 20th century by only about 0.15 Watts per meter squared [W/m2]. Contemporary solar activity reconstructions, however, show that solar activity increased during the 20th century by 1.5 - 4 W/m2 or 10 - 26 times more than assumed by the NASA-GISS model. If one assumes 30% albedo and divide by four [an incorrect and simplistic assumption as demonstrated by Joe Postma], the GISS model uses up to ~5 times less solar forcing anomaly change in comparison to solar proxy data. 

Reconstructed Total Solar Irradiance [TSI] shown in upper right graph shows an increase of  ~ 4 W/m2 over the 20th century
Solar forcing based on these modern reconstructions is 1 - 2.6 times higher than the alleged forcing from increased greenhouse gases during the 20th century. In addition, climate models do not consider any of the multiple solar amplification mechanisms which have been described in the literature. Thus, the IPCC and others dismiss the role of the Sun in climate by conveniently assuming solar activity changed 5 - 13 times less than the research indicates. 

In addition, since solar forcing was much higher than assumed by the models, this implies that CO2 forcing was significantly less than assumed by the models. 


  1. Using the LASP data for annual TSI

    I find that the linear trend is 0.61 W/m2 per century.

    So in the 112 years since 1990, the total linearized change is 0.68 W/m2, which is significantly less than half of your value of 1.5 W/m2.

    1. The simulated data you use is output from a "flux transport model" and is not actual TSI data, and it shows about 1 W/m2 increase from 1900-2000.

      The data I show above is Beryllium 10 isotope records combined with sunspot records - i.e. contiguous records using 2 related proxies and it shows an increase of ~4 W/m2 over the 20th century.

    2. Be10 is model-based (a proxy) as well. Why it is superior? One paper found a reconstruction based on sunspot numbers to be consistent with the Wang et al study:

      Reconstruction of solar irradiance using the Group sunspot number, L. Balmaceda et al

      This model finds an increase in the total solar irradiance since the Maunder Minimum of about 1.3 W/m2, so even less than that for the 20th century.

    3. And you have left out some crucial conclusions of the Shapiro et al work:

      "As we are aware that maintaining a stable calibration to better than 0.1 % over 30 years is very demanding we
      cannot claim that the historical data confirm our reconstruction."

      "...until new evidence become available we are in a situation that different approaches and hypothesis yield different solar forcing values."

      In short, the conclusions of this paper need some serious confirmation, as even the authors admit:

      "Our result allows the climate community to evaluate the full range of present uncertainty in solar forcing."

  2. The change min to max from a low of 1359 in 1700's to 1366 at several later times works out to only a 0.5% difference. 1/2 of 1%. However the sun puts out a lot of energy and there may be feedbacks. Or it's possible that TSI is not the best indicator to use for the sun's effect on climate. Maybe UV is or 1/ln # sunspots (just made that up as an example).

    1. Quite correct that TSI is only a small part of the story. Solar UV varies up to 20% within and between solar cycles and has profound effects upon stratospheric ozone and then climate. Solar UV also penetrates the furthest into the ocean and has the highest energy wavelengths.

      Thats only one of many other solar amplification mechanisms described in the literature demonstrating that TSI alone is inadequate to determine solar effects on climate.

    2. Prior posts on the link between solar UV, stratospheric ozone, and climate:

    3. Again, please quantify "profound." Assume a 20% increase or decrease in solar UV -- what is the subsequent impact on climate?

    4. David, I gave you a number of peer-reviewed papers in the link above to look at. The first listed states such effects are "significant"

      According to the authors, "recent measurements by the SORCE (SOlar Radiation and Climate Experiment) satellite suggest a significantly stronger variability in the ultraviolet (UV) spectral range and changes in the visible and near-infrared (NIR) bands in anti-phase with the solar cycle. A number of recent chemistry-climate model (CCM) simulations have shown that this might have significant implications on the Earth's atmosphere." Solar spectral irradiance "changes influence the Earth's atmosphere, both directly, through changes in shortwave (SW) heating and therefore, temperature and ozone distributions in the stratosphere, and indirectly, through dynamical feedbacks."

      This is an emerging area of research, neglected in the past, since it wasn't even known that solar UV varies so much until a few years ago.

    5. I'm not going to go back and reread your entire site because you won't answer a question in your own words: please quantify "profound," in terms of typical climate parameters. Assume a 20% change in solar UV. What is the resulting forcing?

    6. I already told you this is an emerging, new area of research within only the past couple of years and the so-called "forcing" has not been quantified. "Forcing" is an antiquated notion anyway in a dynamic, immensely chaotic system in which a given forcing never remains static or predictable and is interdependent upon other unpredictable forcings.

      Note that if you aren't going to bother to at least read the links I post, I'm not going to waste any more time looking them up for you

  3. And this reconstruction finds only a 0.9 W/m2 increase since the Maunder Minimum:

    Total solar irradiance during the Holocene
    F. Steinhilber1, J. Beer1, C. Fröhlich2
    Geophysical Research Letters
    Volume 36, Issue 19, October 2009

    1. And here's one that found "the average open solar flux during the Maunder minimum is found to have been 11% of its peak value during the recent grand solar maximum."

      Global brightening in late 20th century increased at 6.6 Wm-2 per decade [which may be related to solar amplification/cloud decrease]

      prior posts showing solar activity in the latter 20th century was at the highest levels of the past several thousand years

      We can argue whether TSI increased during the 20th century by 0.9, 1, or 1.5-4 Wm-2 as I noted in the post, but the fact is all of these estimates significantly exceed 0.3Wm-2 used in the NASA GISS model.

      Even more importantly, TSI is an inadequate measure of solar forcing, and does not provide any information about solar amplification effects or the large changes in solar spectrum, especially solar UV of up to 20%

      Further, how do you explain the Holocene Climate Optimum, Egyptian, Minoan, Roman, Medieval Warm Periods [all of which were warmer than the present] without changes in solar activity & solar amplification mechanisms?

    2. Changes in solar irradiance simply aren't that effective. To first order, from the Stefan Boltzmann law

      dT/T = (1/4)(dS/S)

      where S is TSI. So even for dS = 4 W/m2, dT ~ 0.2 K.

      It is far from clear that any of the warm periods you list were global phenomena. Regional changes happen for lots of reasons.

    3. You again assume no solar amplification whatsoever.

      If you claim a 4W/m2 forcing causes a dT ~ 0.2 K, why do you think the alleged 3.7W/m2 TOA forcing from doubled CO2 would lead to a dT ~ 3K?

      It is absolutely clear that those warm periods were global and warmer than the present. has over 1,200 peer-reviewed papers from every corner of the globe in its Medieval Warm Period Project that prove the MWP was global and hotter than the present.

    4. David, if you are going to make ad hom, "denier" or abusive comments, they will be deleted per the comment policy. It is clear that your comments reveal lack of any objective interest in exploring any possible explanation other than AGW. You dismiss over 1,000 peer-reviewed papers in mainstream scientific journals by over 1,200 scientists just because links to them, due to your desire to believe in the fallacy that the MWP was local. So, stop wasting my time with your CAGW propaganda.

    5. If you claim a 4W/m2 forcing causes a dT ~ 0.2 K, why do you think the alleged 3.7W/m2 TOA forcing from doubled CO2 would lead to a dT ~ 3K?

      Because one reduces OLR, and the other is an increase in incoming shortwave radiation.

    6. 1. The IPCC makes no such distinction that 1 W/m2 of solar forcing is any different from 1 W/m2 GHG forcing

      2. In fact, OLR has increased with increased GHGs, the opposite of GHE theory

      3. In fact, a 1 W/m2 increase in solar shortwave has much more warming effect on earth than a 1 W/m2 alleged increase in LWIR from GHGs, because only solar shortwave can penetrate the ocean surface to heat the bulk of the oceans. LWIR only causes evaporative cooling of the ocean skin layer.

    7. You dismiss over 1,000 peer-reviewed papers in mainstream scientific journals by over 1,200 scientists just because links to them.

      I don't dismiss the individual papers, I dismiss the way CO2 science has organized them and the claims they have made about them. Their methodology is well known to be faulty:

      Meanwhile, real scientific work like that from PAGES comes to a much different view:

      "In summary, in answer to the question posed above regarding the spatial and temporal scales of the MCA, the general consensus of the participants is that
      in the past 15 years additional evidence has become available of a climatic anomaly occurring during the time interval ca. 900-1300 AD, albeit with important differences regarding the timing and spatial extent. The participants also stressed that a Northern Hemisphere or global mean value is of less relevance when looking at the regional spatial scales where the impacts of climatic anomalies are experienced."

      Note especially the last clause of the first sentence.

    8. Steve McIntyre summaries the curious & cherry-picked reconstructions used by PAGES, many of which he and others have previously debunked.

    9. Heat radiation can solar radiation aren't equivalent. Just one example is albedo and how various wavelenghts reflect. In any case, there is little support for a 4 W/m2 increase in TSI over the last century. And you've been unable to quantify changes due to UV changes.

      It is interesting how you people are all fine with accepting proxies and models when they support your view, and rejecting them when they do not.

    10. Blog posts aren't science. When McIntyre gets his PAGES critique published in the peer reviewed literature, it will be possible to take it seriously. Until then it's just a blog.

      CO2 science did similar tricks with methodology as did Soon & Baliunas 10 years ago. I tore that apart in Scientific American, and it taught me that some people will resort to all kinds of tricks to try and mislead people. They are very obvious once you start digging into them, as is CO2's science. I learned not to trust any of them, and to be very skeptical.

    11. You apparently don't understand the difference between heat and radiation. "Heat radiation" is a misnomer to a physicist, but it's not my job to educate you.

      There's a lot of support for a 1.5 to 4 W/m2 increase in TSI over the 20th century, as I stated in the post. This doesn't include any solar amplification effects, which have been shown from direct observations to be 6.6 W/m2 per decade in the latter 20th century from global brightening alone.

      Your logic appears to be that because I can't quantify the amount of solar UV "forcing" then it must be bunk. Likewise, the IPCC can't quantify a CO2 forcing effect within the huge range of 1.5-4.5C, and gave up on a central estimate, that must be bunk as well.

      Self projection: "It is interesting how you people are all fine with accepting proxies and models when they support your view, and rejecting them when they do not." applies much much more to AGW proponents.

    12. Sci Am articles are not peer reviewed science either. Peer-review or "pal-review" is often corrupted by conflicts of interest. I know first hand from my publications in the peer-reviewed literature.

      David, I've got other things to do now, so am ending the comments on this thread as we're just going around in circles on the same points. Bye

    13. Sci Am articles are not peer reviewed science either.

      Read my article. It lays out very clearly the logical problems with the Soon & Baliunas paper. They did very, very poor science.

      The only question really is, was it on purpose?

    14. I read your Sci Am article on Soon and Baliunas...

      I have also read almost every abstract published in the paleoclimate literature over the past 5 years, and in many cases, paid for the full papers and feature graphs from the papers on this site. I fully agree with their conclusion that "across the world, many records reveal that the 20th century is probably not the warmest nor a uniquely extreme climate period of the last millennium."

      Here's 30 recent "non-hockey-sticks" for a sampling

      You apparently didn't understand that many paleoclimate indicators such as d18O and tree-rings are used as proxies for both temperature & precipitation, thereby slandering Soon & Baliunas use of these indicators for both temperature & precipitation. In fact, this is routinely done in hundreds of paleoclimate papers due to the Clausius-Clapeyron relation.

      Paleoclimate proxies are also not exact with respect to dating, so your criticisms about that are also dubious.

      David, why don't you do some real science investigative reporting on clear-cut frauds from the CAGW side such as these:

    15. David,

      I realize you wrote that article before Climategate, but how can you possibly imply Soon & Baliunas are frauds while keeping tight lipped about the supposed pillars of science Mann & Jones quoted in your article, two of the biggest frauds in the history of science?

  4. Dave can't give it up. He has staked his future on being a climate scientist. You can't be a climate scientist unless you defend the faith.

    1. This is data, not faith. I have presented several papers that show a TSI change of less than 1 W/m2 in the 20th century. Do you have better data? If not, then it's your position that is based on faith, not mine.

    2. Appell is not a climate scientist - he's a journalist

  5. Recent variability of the solar spectral irradiance and its impact on
    climate modelling


  7. New paper shows 20th century solar activity was at highest levels of past 9,400 years

  8. New post today:

    Are you listening David?



  11. Models also do not consider the time-integral of solar activity and the great inertial lag of the earth-atmosphere system

    “Temporal changes in the power of the longwave radiation of the system Earth-atmosphere emitted to space always lag behind changes in the power of absorbed solar radiation due to slow change of its enthalpy. That is why the debit and credit parts of the average annual energy budget of the terrestrial globe with its air and water envelope are practically always in an unbalanced state. Average annual balance of the thermal budget of the system Earth-atmosphere during long time period will reliably determine the course and value of both an energy excess accumulated by the Earth or the energy deficit in the thermal budget which, with account for data of the TSI forecast, can define and predict well in advance the direction and amplitude of the forthcoming climate changes. From early 90s we observe bicentennial decrease in both the TSI and the portion of its energy absorbed by the Earth. The Earth as a planet will henceforward have negative balance in the energy budget which will result in the temperature drop in approximately 2014. Due to increase of albedo and decrease of the greenhouse gases atmospheric concentration the absorbed portion of solar energy and the influence of the greenhouse effect will additionally decline. The influence of the consecutive chain of feedback effects which can lead to additional drop of temperature will surpass the influence of the TSI decrease. The onset of the deep bicentennial minimum of TSI is expected in 2042±11, that of the 19th Little Ice Age in the past 7500 years – in 2055±11.

    reference link



  14. New paper published yesterday by Leif’s friend Judith Lean finds the difference in TSI measured during the 1990s by solar radiometers vs. with SORCE could alone account for 0.4C temperature change, without any amplification or consideration of 2nd order effects. But, no problem, all we have to do is change the cloud cover in our models to make it all balance out on a global basis… Hold on, that changes regional climate simulations…

    The Impact of Different Absolute Solar Irradiance Values on Current Climate Model Simulations

    Simulations of the pre-industrial and doubled CO2 climates are made with the GISS GCMAM using two different estimates of the absolute solar irradiance value, a higher value measured by solar radiometers in the 1990s and the lower value measured recently by SORCE. Each of the model simulations is adjusted to achieve global energy balance; without this adjustment the difference in irradiance produces a global temperature change of 0.4°C, comparable to the cooling estimated for the Maunder Minimum. The results indicate that by altering cloud cover the model properly compensates for the different absolute solar irradiance values on a global level when simulating both the pre-industrial and doubled CO2 climates. On a regional level, the pre-industrial climate simulations and the patterns of change with doubled CO2 concentrations are again remarkably similar, but there are some differences. Using a higher absolute solar irradiance value and the requisite cloud cover affects the model’s depictions of high latitude surface air temperature, sea level pressure, and stratospheric ozone, as well as tropical precipitation. In the climate change experiments it leads to an underestimation of North Atlantic warming, reduced precipitation in the tropical Western Pacific, and smaller total ozone growth at high northern latitudes. Although significant, these differences are typically modest compared with the magnitude of the regional changes expected for doubled greenhouse gas concentrations. Nevertheless, the model simulations demonstrate that achieving the highest possible fidelity when simulating regional climate change requires that climate models use as input the most accurate (lower) solar irradiance value.

  15. Another graphic showing the GISS model solar forcing assumptions: