Pinker et al: Do Satellites Detect Trends in Surface Solar Radiation?

Posted: April 10, 2013 by tallbloke in Analysis, climate, Dataset, Natural Variation, Solar physics, solar system dynamics

Errrmm, why I have not heard of this 2006 paper before? 1.6W/m^2 per decade is  a not insignificant trend. Did the IPCC ignore this?

Do Satellites Detect Trends in Surface Solar Radiation?
R. T. Pinker,1 B. Zhang,2 E. G. Dutton3

Long-term variations in solar radiation at Earth’s surface (S) can affect our
climate, the hydrological cycle, plant photosynthesis, and solar power. Sustained
decreases in S have been widely reported from about the year 1960 to
1990. Here we present an estimate of global temporal variations in S by using
the longest available satellite record. We observed an overall increase in S from
1983 to 2001 at a rate of 0.16 watts per square meter (0.10%) per year; this
change is a combination of a decrease until about 1990, followed by a sustained
increase. The global-scale findings are consistent with recent independent
satellite observations but differ in sign and magnitude from previously
reported ground observations. Unlike ground stations, satellites can uniformly
sample the entire globe.


Full paper here

  1. They were not alone:

    “Here are the wattage changes reported in Science:

    Enhanced greenhouse effect during industrial era: 2.4 W/m2. According to page 66 of the 2001 compendium of the United Nations’ Intergovernmental Panel on Climate change (IPCC), about a quarter of this amount, or 0.6 W/m2, has occurred since the mid-1980s.

    Change in solar radiation absorbed by the earth from 2000 to 2004, estimated from low-orbiting satellite data, reported by Wielicki et al.: 2.06 W/m2.

    Change from 1983 to 2001 in solar radiation absorbed by the earth, estimated at the surface by satellites, reported by Pinker et al.: 2.7 W/m2.

    Change from 1985 to 2000 solar radiation absorbed at the surface, as measured at the surface, reported by Wild et al.: 4.4 W/m2.”

    Wielicki et al

    Wild et al

  2. J Martin says:

    Presumably a more up to date graph for the relevant satellite can be obtained from somewhere.

  3. Stephen Wilde says:

    Could cloudiness variations account for those numbers ?

  4. Roger Andrews says:

    “Could cloudiness variations account for those numbers ?”

    Well, it certainly wasn’t volcanic eruptions 🙂

  5. Ned Nikolov says:


    There has been several papers over the past 8 years that provide support for the notion that decadal and centennial changes in global surface temperature are most likely due to solar-activity induced variations of global cloud cover and Earth’s cloud albedo. Empirical observations (both ground- and satellite based) reveal intermittent periods of global ‘brightening’ and ‘dimming’. Look at these references:

    Wild, M. 2009. Global dimming and brightening: A review. J. Geophys. Res., 114, D00D16, doi:10.1029/2008JD011470

    Pallé, E., P. R. Goode, and P. Montañés-Rodríguez. 2009. Interannual variations in Earth’s reflectance 1999–2007, J. Geophys. Res., 114, D00D03, doi:10.1029/2008JD010734.

    The increase in the observed surface solar radiation over the past 30 years is actually sufficient to explain the entire warming over the same time period. At the same time, climate models show no skill in predicting these global ‘brightening’ and ‘dimming’ periods. Instead, they approximate the observed warming since 1980 using only CO2. This also documented in the peer-reviewed literature, see:

    Wild, M. 2009. How well do IPCC-AR4/CMIP3 climate models simulate global dimming/brightening and twentieth- century daytime and nighttime warming? J. Geophys. Res., 114, D00D11, doi:10.1029/2008JD011372. (

    This is a good example about how models can simulate reality relatively well but for the wrong reason. Having the wrong driver in a model may allow you to reproduce successfully past observations but will certainly fail to predict future dynamics and trends of the system.

  6. Stephen Wilde says:

    I agree with Ned’s diagnosis and should repeat my previous proposal here.

    High solar activity causes a horizontal shrinkage of the polar air masses, poleward and more zonal jets, less clouds, more energy into the oceans and a warming trend.

    Low solar activity does the opposite.

    The cloudiness changes are due to the change in the length of the lines of air mass mixing between zonality (short) and meridionality (long). On that basis we would no longer need the Svensmark hypothesis.

    The cause of the latitudinal shifting is a change in the slope of the tropopause height between equator and poles. That change in slope results from differential solar effects on the temperature of the stratosphere at equator and poles.

  7. tallbloke says:

    Thanks all for additional info. I’m aware of the Earthshine papers of Palle et al, but hadn’t seen the Pinker paper or Wild’s paper before.

    “There’s your global warming, right there.”

  8. tallbloke says:

    Doug proctor said on the suggestions page:

    Submitted on 2013/04/10 at 8:37 pm
    Hi, Roger,

    I’m putting this here and not on the blog wrt Pinker et al in case I am completely off base. I’ve been there before. If my simplistic math looks okay to you, then you can copy it to the blog.

    I dunno. We figure what we can if we no longer feel we can count on the “experts” to tell us what we think they are telling us. It has become a messy world.

    Okay, here goes with how I see it, rightly or wrongly:


    1. All energy comes from the Sun and on only one side of the planet.

    2. Whatever is not reemitted by the sunlighted side must be reemitted by the dark side to maintain stable temperatures.

    Whatever happens, the world warms as a function of how the darkside manages reradiative release.

    3. The world can warm either by

    a) increasing TSI overall (brighter sun) while maintaining prior absolute or proportional levels of reflection, refraction and reemissions, or

    b) maintaining a stable TSI, but increasing the amount of SI absorbed by the atmosphere and ground (less daytime clouds) or

    c) maintaining a stable TSI and daytime cloud cover but increasing the amount of SI absorbed by the atmosphere and ground (GHGs, aerosols and albedo effects).

    Still, temperatures will rise on Earth only if the nightside does not reemit at a rate equal to the increased absorption rate on the sunlit side.

    At the same time, the world can also warm by

    4) maintaining a stable TSI, a stable cloud cover during the daytime, a stable atmospheric content and overall albedo, but decreasing the amount that is reemitted on the darkside (increased low level clouds).

    Again, no matter how you warm the planet, during the warming phase there is less energy being emitted on the night side than there has been retained by sundown on the sunlit side.

    As I read Pinker et al, they are picking up an increase of ground measured SI between 1983 and 2001 of 0.16 w/m2-yr (planetary average), or 2.88 W/m2. (This assumes measurements were with cloud cover as occurred (???) otherwise, the number impacting the lower atmosphere and ground has to be decreased by cloud cover % X reflectivity of clouds)
    On that basis, :

    1. Since 1983 to 2001, the SI at ground level has increased 2.88 W/m2. With an (clear) air absorption number of 0.20 (from somewhere, debatable and re-insertable; let’s leave this as is for the purpose of this discussion), an increase of ground SI of 2.88 W/m2 means an increase of TOA TSI of 3.6 W/m2. The clear air absorption is then 0.72 W/m2.

    The warming component is then 2.0 X albedo + increased atmospheric absorption from TOA to ground. If the albedo has been constant (0.293!!) then the amount heating the planet since 1983 is

    2.04 + 0.72 = 2.76 W/2.

    Since the SI only comes in on one side of the planet at a time, the SI increase is actually twice or 5.52W/m2. This then tells us about what to look for on the night side.

    In a temperature neutral world, the nightside loss would have increased between approximately 5.5 W/m2 since 1983 (to keep the temperature at the 1983 level). However, we know this would not initially happen (if we didn’t have a heat loss rate slightly less than heat retention rate, nighttime vs daytime, our daily surface temp variations would be the same as the Moon). But this WOULD occur once a new thermal stability were reached. So, once the warming phase stopped, nighttime emissions would have increased 5.5 W/m2 (albeit with a higher temperature).

    Based on the Pinter et al article, I would expect to see an increase in nightside emissions, towards but less than 5.5 W/m2. The difference is the net heating amount.

    Now consider a CO2-only warming world:

    In a CO2-only warming world, the TSI is fixed. In order for temperatures to go up, however, what goes out still has to be less than what comes in. Nighttime emissions in a CO2 warming world have to decrease from what they were before the CO2 warming started. It is the energy introduced during the day that is retained through the night until morning that warms the planet. The CO2-induced warming, however, is still the difference between in-coming in and out-going energy as before. As temperatures rise the emissions will increase, of course, but there will always be a difference between what was going out and what is going out (until the new stability is reached).

  9. Ned Nikolov says:


    Assigning an actual ‘radiative forcing’ to CO2 and mixing it up with true forcings such as variations in the absorbed solar radiation is a capital mistake! Think about why …

    BTW, do you, guys, know what is the deep physical nature of a radiation flux?

    If we look at the most fundamental physical quantities (called dimensions) that make up our units (such as Mass M, Length L, and Time T), something profound emerges. Thus, radiation fluxes are measured in units of W m-2. Decomposing this unit into sub-units, we get:

    W m-2 = (J/s) m-2 = [(N m)/s] m-2 = [(kg m/s^2) m/s] m-2 = kg s-3

    So, in terms of fundamental dimensions, a radiation flux is simply Mass per Time cubed (M/T^3).

    Now, let’s look at pressure, which is commonly measured in Pascal (Pa), which is force per unit area:

    Pa = N m-2 = (kg m/s^2) m-2 = kg/(m s^2)

    Hence, in terms of fundamental dimensions, the pressure is simply Mass per Length per Time squared, i.e. M/(L T^2).

    Lets compare the fundamental dimension of a radiation flux with that of pressure:

    Rflux => M/T^3 while Pressure => M/(L T^2)

    One immediately notices that

    Rflux = Pressure * L/T = Pressure * Speed

    In other words, at the most fundamental level, a radiation flux is nothing more than a product of photon pressure and the speed of light. Indeed, photons (although mass-less) have a momentum and exert real pressure! Since the speed of light is constant in a given medium, the radiation flux can only vary as a function of photon pressure… Radiation pressure is a measurable physical quantity that perturbs the orbits of man-made satellites and can even be harnessed to propel spacecrafts in Space, see:

    Why am I bringing this up? … Remember our discussion some 12 months ago about the role of atmospheric pressure in enhancing the mean global surface temperature above that of an airless body such as the Moon (i.e. the pressure-induced thermal enhancement that explains the so-called ‘Greenhouse Effect’)? Remember how learned folks such as Dr, Brown, Dr. Joel Shore and Anthony Watts (WUWT) accused us of a mortal crime of violating the Energy Conservation Law by proposing that atmospheric pressure could be responsible for the observed thermal effect of the atmosphere? Well, little do these guy know, their favorite forcing, the electromagnetic radiation, cannot exist without pressure!

    The above is discussed in greater detail in one of our upcoming science papers … 🙂

  10. Roger Andrews says:

    According to Pinker et al’s Figure 5, reproduced below for reference, solar radiation over the oceans increased by about 5 w/m2 between 1983 and 2001 while solar radiation over land areas decreased slightly. How does this happen?

    Also, does anyone have an explanation for the abrupt +/- 10 w/m2 downward excursion in the ocean record in 1994?

  11. tallbloke says:

    Ned, please see recent post by Wayne. Have you emailed David re regolith term? Looking forward to the new paper!

    Miles Mathis points out that mass itself is a second order abstraction, defined by volume and density. So once again we can see that at the fundamental level, it breaks down to length (in three dimensions for volume) and density. The density can be thought of in terms of distances too it seems to me. The closeness of the packing together of the constituent particles of a substance, and the geometry of the elemental construction of the atomic nuclei.

  12. Stephen Wilde says:

    “The closeness of the packing together of the constituent particles of a substance, and the elemental construction of the atomic nuclei”

    Yes, because it is the density of such material in each unit of volume that determines the strength of any resistance to the flow of solar energy through that volume.

    However you do also need to consider the totality of the available mass as well as the total volume that it occupies when considering a planetary atmosphere which can expand and contract without any change in total mass.

    In general an increase in volume whilst keeping total mass the same would permit a faster flow of energy through the atmosphere due to the reduced density within each unit of volume.

    So you could in theory get an increase in the energy held by a constituent molecule due to a slowing down of energy throughput caused by its higher absorption capacity which then causes an expansion but the expansion allows the initial rate of throughput to be restored.

    The net effect is more energy held in the atmosphere but no rise in equilibrium temperature and a stable throughput of energy.

    The reason that the extra energy in the atmosphere cannot affect temperature is because it is held as PE within the higher atmosphere which is then maintained by a more vigorous circulation.

    Note that this narrative assumes a net increase in retained energy from a changed composition and that is not yet properly confirmed for CO2.

  13. Stephen Wilde says:

    I should have said, ‘amount of mass in each unit of volume’ rather than density in each unit of volume but that should be obvious from the context.

  14. Slightly off topic.
    The Sun
    “BRITAIN’S winters are getting colder because of melting Arctic ice, the Government’s forecaster said yesterday.

    “Met Office chief scientist Julia Slingo said climate change was “loading the dice” towards freezing, drier weather — and called publicly for the first time for an urgent investigation.”

    Prof Slingo said: “If you look at the way our weather patterns have behaved over the past four or five years, we’re beginning to think that there is something happening. ”

    So climate isn’t 30 years, it’s now 4 years and why did they predict warmer wetter winters? Shows they haven’t got a clue about our climate.

  15. Ned Nikolov says:


    Yes, I emailed David my comments on his paper …

  16. Ned Nikolov says:


    BTW, in terms of fundamental dimensions, density is Mass per cubed Length (M/L^3). In the atmosphere, density is a product (function) of Pressure and Temperature. It is NOT a driver of temperature as some get confused about. Temperature in turn depends entirely on incoming radiation and pressure …

  17. Bob Tisdale says:

    Tallbloke asked in the post, “Errrmm, why I have not heard of this 2006 paper before? 1.6W/m^2 per decade is a not insignificant trend. Did the IPCC ignore this?”

    The multi-model mean of the models stored in the CMIP5 (IPCC AR5) archive show a flat trend (slight decrease) in surface DSR, even with the two big dips and rebounds from El Chichon and Mount Pinatubo:

    I’m working on a post that includes a cross post of this one, Tallbloke, and that also introduces readers to the NCEP-DOE Reanalysis-2 Surface Downward Shortwave Radiation data, which, as shown above, also shows a significant increase over the last 3+ decades…most of the trend coming from the extratropics of the Southern Hemisphere (0.3 watts/m^2/decade)–that’s a lot. Hopefully, I’ll have the post done by tomorrow.


  18. tallbloke says:

    Bob, excellent. My calcs on sea level rise also found 4W/m^2 FOR THE 1993-2003 decade but were shouted down on WUWT.

  19. Ned Nikolov says:

    To: Bob Tisdale (April 11, 2013 at 4:19 pm):


    This is correct. Climate models predict a decline in surface solar radiation (global dimming), which is the exact opposite of observations showing a global brightening for the past 30 years. This fact has been reported in papers by Wild (2009), see my post above:

    Of course, the IPCC high priests don’t bother looking at inconvenient observations … 🙂

    I maintain that all warming/cooling periods during the climatically stable Holocene (past 9,000 years) have been primarily caused by solar-induced variations in global cloud cover (there is of course a small effect from long-term orbital changes). These climate fluctuations have been limited globally to plus-minus 0.8C or about 1.6C total temperature change (amplitude) …. We are currently at the peak of one such warming/cooling cycle, which began in 1675. Global temperature cannot increase any more because Sun’s magnetic activity is now declining, and the cloud-cover decrease stopped in year 2000. Global loud cover and Earth’s abedo have been stable for the past 12 years, but are likely to start increasing within next 2-3 years… One should remember that a 1.6 C change in global temperature only requires about 2% change in global cloud cover. This is really a small change considering that the average global cloud cover is about 65% …

  20. oldbrew says:

    “BRITAIN’S winters are getting colder because of melting Arctic ice, the Government’s forecaster said yesterday.”

    Most of the recent cold weather came from Siberia not the Arctic.

  21. […] Pinker et al: Do Satellites Detect Trends in Surface Solar Radiation? […]

  22. Tenuc says:

    Ned Nikolov says:
    April 11, 2013 at 2:37 am
    “…a radiation flux is nothing more than a product of photon pressure and the speed of light. Indeed, photons (although mass-less) have a momentum and exert real pressure!…”

    Hi Ned, I find this an interesting comment, but why not go the whole hog and have the photon be a real particle?

    It would be strange if an object, like a photon, could have momentum and be able to be deflected and exert pressure through collisions with atoms, while having zero mass.

    Using E=MC^2 it is easy to estimate the mass of a photon of a specific wavelength…

    Using one of the ubiquitous infra-red photons with a wavelength of 10^-4m, for example, its energy is ~2.5 x 10^-20J, so its equivalent mass is ~2.8 x 10^-37kg.

    Looking forward to reading your new paper.

  23. Bob Tisdale says:

    Tallbloke, I just dropped by to leave some links, but you or WordPress beat me to it. Thanks.


  24. tallbloke says:

    Excellent work Bob, thanks for taking this up. The calculation I did a few years ago of the extra forcing on the ocean required to achieve the 1993-2003 increase in sea level due to the steric component shown by the satellite altimetry was around 4W/m^2. On WUWT, other commenters were convinced I’d made an order of magnitude error and that it should be 0.4W/m^2

    I note that the Palle et al, Wild and Pinker papers go a long way to vindicating my position. Clearly the Colorado dataset is biased high for the seal level rise rate, but equally clearly, the biggest cause of the increase in rise rate was diminished cloud cover, not increased airborne co2.

  25. tallbloke says:

    It’s instructive to compare the NCEP re-analysis in Bob’s post with the sunspot number:

    Cloud seems to increase near the peak of cycles 21 and 22, but not following the big 98 el nino.

  26. oldbrew says:

    ‘It would be strange if an object, like a photon, could have momentum and be able to be deflected and exert pressure through collisions with atoms, while having zero mass’

    Sound has zero mass but has effects?

  27. Tenuc says:

    Great stuff Bob – nailed it. I also think Tallblokes graph is on the money and clearly illustrates how dominant the solar cycle is regarding climate.

    It is interesting that there seems to have been a phase change starting solar cycle 23, with SSN lagging rather than leading.

    Copied this chart plotting Hadcrut4 GM v SIDC monthly SSN from WUWT a few days ago, but can’t find who posted it or where….

    Shows excellent correlation from 1855 to 2996, then breaks down with temperature increasing whilst SSN decreases. I think this divergence could be due to an early onset of the L&P effect, which has depressed sun spot observation and the way the temperature record has been manipulated to support the CAGW scam over recent years.

    The theory that CO2 is a driver of climate is now so full of holes its looking like Emmental cheese, though not as palletable… 🙂

  28. Tenuc says:

    oldbrew says:
    April 12, 2013 at 3:58 pm
    Tenuc says:[…‘It would be strange if an object, like a photon, could have momentum and be able to be deflected and exert pressure through collisions with atoms, while having zero mass’…]

    “Sound has zero mass but has effects?”

    True, but sound waves travel differently to photons and require a medium to travel through. Conversely photons zip along fastest in an absolute vacuum with denser materials slowing them down via collision.

  29. John says:

    Solar dimming and brightening isn’t a new or obscure issue, there are many papers on the subject. For instance, Martin Wild, JGR 2009, “Global dimming and brightening: A review.” The article just before the Pinker article in Science is titled “From Dimming to Brightening:
    Decadal Changes in Solar Radiation at Earth’s Surface.”

    Human emissions of SO2 is the precursor for tropospheric ammonium sulfate due to human activies (volcanos are also a major, though intermittent, source of sulfate). Sulfate relects sunlight (as a whitish haze) on reasonably clear days, and causes clouds to become whiter than they would otherwise be on cloudy days, also increasing amoungs of sunlight reflected. Sulfate is not the only human emission which affects how much sunlight gets through to the earth’s surface, but it is the most important one. Coal and oil both have sulfur to varying degrees, depending on source and type of coal and oil. Power plants can remove virtually all sulfur emissions with the use of “scrubbers,” but scrubbers didn’t begin to be used in the US until the 1970s. Refineries can remove the amounts of sulfur in residual oil, gasoline, diesel, etc. So the amount of SO2 emissions in a given year depends upon how much of each fuel is burned, and the degree of SO2 controls at different parts of the system.

    SO2 emissions from human activites rose and then stabilized for much of the 1970s through early 1980s. When the Soviet Union (and eastern Europe) governments fell, very dirty, heavily subsidized industries could no longer be heavily subsidized. So from 1989 through about 1991, there was a large drop in tropospheric sulfate from industrial activities. Throughout the 1990s, sulfate in the US and Western Europe fell because of acid rail laws. The 1990s is the decade when dimming stopped and brighening occurred.

    Sulfate levels began to climb again around 2000, as China began its long ramp up of coal use (with no SO2 controls) to power their economy. See figures in “Anthropogenic and natural contributions to regional trends in aerosol optical depth, 1980–2006”, by Streets et al, JGR 2009.

    Another paper is “Aerosol and cloud effects on solar brightening and the recent rapid warming” by Ruckstuhl et al. GRL, 2008. Here is the Abstract:

    “The rapid temperature increase of 1 degree C over mainland Europe since 1980 is considerably larger than the temperature rise expected from anthropogenic greenhouse gas increases. Here we present aerosol optical depth measurements from six specific locations and surface irradiance measurements from a large number of radiation sites in Northern Germany and Switzerland. The
    measurements show a decline in aerosol concentration of up to 60%, which have led to a statistically significant increase of solar irradiance under cloud-free skies since the 1980s. The measurements confirm solar brightening and show that the direct aerosol effect had an approximately five times larger impact on climate forcing than the indirect aerosol and other cloud effects. The overall aerosol and cloud induced surface climate forcing is ~ +1 W meter squared per decade and has most probably strongly contributed to the recent rapid warming in Europe.”

    There is also a 2010 collection of 23 articles which appeared in AGU journals on the issue of solar dimming and brightening:

  30. Ned Nikolov says:

    In regard to the reported increase of 0.16 W m-2 per year in Surface Solar Radiation by Pinker et al., this translates into 2.88 W m-2 total increase in the incoming solar flux between 1981 and 2001. Taking into account the 0.13 average albedo of Earth’s surface, we can calculate the total extra amount of solar radiation absorbed by the surface: 2.88*(1 – 0.13) = 2.5 W m-2.

    Our (N&Z) analysis indicates that the equilibrium sensitivity of Earth’s global temperature to variations in absorbed radiation is 0.3 K per 1 W m-2. This means that the expected increase in equilibrium temperature according to Pinker data is 0.3*2.5 = 0.75 C for 18 years (1983 to 2001).

    Using the much smaller rate of solar radiation increase of 0.22 W m-2 per decade derived from the NCEP-DOE Reanalysis-2 by Bob, we estimate a 0.35 W m-2 total increase in the sunlight absorption by the Earth surface in 18 years. This translates into a global temperature increase of 0.35*0.3 = 0.1 C for this period.

    The observed temperature change between 1981 and 2001 according to both surface- and satellite observations is about +0.28 C. This value is much smaller than 0.75 C, but bigger than 0.1 C. Given the reasonable expectation that the actual increase in surface solar radiation is most likely somewhere between the estimates by Pinker et al and the NCEP-DOE reanalysis, one can easily reason that the the warming measured over the past several decades might be fully explainable by the observed changes in surface solar flux caused by variations in global cloud cover … There you have it!

  31. Ned Nikolov says:

    Here is an interesting paper discussing the ‘brightening’ observed over the Continental US between 1995 and 2007:

    Long, C. N., et al. (2009). Significant decadal brightening of downwelling shortwave in the continental United States, J. Geophys. Res., 114, D00D06, doi:10.1029/2008JD011263

    The authors conclude that the reduction of cloud cover must be the main cause for the measured significant increase in surface solar radiation over the study period !

  32. tallbloke says:

    welcome John and thanks for your review.

    Good find Ned.