Considering the sun in climate change

There is a lot of debate about the sun’s role in global warming and climate change. Some scientists argue that the sun plays the dominant role, making human activity insignificant.

Much of this argument is based on statistical analysis of very long proxy records. One can see a very good example of this thinking, as well as the debate surrounding it, in a recent article on Judith Curry’s Outstanding “Climate, Etc.” science blog.

The article is titled “Nature Unbound VI Centennial to millennial solar cycles.” In keeping with blog practice, the author is simply Javier. (Who the author is, is generally considered irrelevant.) As the “VI” indicates, this is the sixth in a series of detailed reviews of important aspects of natural variability, all written by Javier.

Curry’s blog is a great place where climate science gets discussed and debated in detail, with all sides well represented. Many of the articles are long and somewhat technical. In fact Climate Etc. is often very much like a scientific journal. The extensive comments are what is called post publication peer review in the journal world.

There are over 850,000 comments to date, many quite technical. This blog may be the best place in the world to see the climate science debate in action. Its educational value is unparalleled.

Most of these articles are what would be called review articles in a journal. Many journals publish review articles and some publish nothing else. These articles attempt to summarize a specific body of research. In this case we have a review of some of the numerous correlations that have been found between very long term climate change and changes in solar activity.

The article is quite long and somewhat technical in places. The starting summary gives the flavor of the piece:

Summary: Holocene climate has been affected in different periods by several centennial to millennial solar cycles. The ~1000-year Eddy solar cycle seems to have dominated Holocene climate variability between 11,500-4,000 years BP, and in the last two millennia, where it defines the Roman, Medieval, and Modern warm periods. The ~208-year de Vries solar cycle displays strong modulation by the ~2400-year Bray solar cycle, both in its cosmogenic isotope signature and in its climatic effects. The Centennial, and Pentadecadal solar cycles are observable in the last 400-year sunspot record, and they are responsible for the present extended solar minimum that started in 2008.”

The basic problem with the sun-climate connection is our lack of understanding of how it works, even while the evidence for it is quite strong. Javier puts this nicely in the introduction, as follows:

The study of solar cycles and their climatic effect is hampered by a very short observational record (~400 years), an inadequate understanding of the physical causes that might produce centennial to millennial changes in solar activity, and an inadequate knowledge of how such changes produce their climatic effect. Despite this lack of a solid theoretical framework, paleoclimatologists keep publishing article after article where they report correlations between solar proxy periodicities and climate proxy periodicities, and the observational evidence is now so abundant as to obviate the lack of a theory or well defined mechanism.”

The US Global Change Research Program spends well over $2 billion a year on so-called climate research, but almost none of that is on trying to understand the hugely important sun-climate connection. Instead, the research program assumes that climate change is due to human activity, so it is focused on things like the carbon cycle. This questionable assumption stands out in the USGCRP’s highly alarmist “Climate Science Special Report.”

If the assumption of human causation is false, which seems likely, then the science is misdirected and the money wasted. It is time for the multi-billion dollar USGCRP to focus on understanding the sun-climate connection. We need to see the sun in climate change.


About the Author: David Wojick, Ph.D.

David Wojick is a journalist and policy analyst. He holds a doctorate in epistemology, specializing in the field of Mathematical Logic and Conceptual Analysis.

  • Mnestheus

    We Republicans deserve a better epistemologist

    And a fact checker-”

    “The study of solar cycles and their climatic effect is hampered by a very short observational record (~400 years)”

    That’s not true- Chinese astronomic observations of the solar surface go back millenia , and harvest date tables have been compiled since Sumerian times.

    “, an inadequate understanding of the physical causes that might produce centennial to millennial changes in solar activity, and an inadequate knowledge of how such changes produce their climatic effect. Despite this lack of a solid theoretical framework, paleoclimatologists keep publishing article after article where they report correlations between solar proxy periodicities and climate proxy periodicities, and the observational evidence is now so abundant as to obviate the lack of a theory or well defined mechanism.””

    That’s the astrophysicists problem, not the palaeoclimatologists- the proxy record speaks for itself, and isotopic temperature proxies are so empirical and reproducible that even Willie Soon goes cherry picking in that abundant scientific orchard.

    • David Wojick

      You should go argue with Javier and the others on Climate Etc. I am merely reporting that this debate exists. However, I do not know what you mean when you say that the proxy record speaks for itself. Javier’s piece is based on the proxy record.

      But that the USGCRP refuses to fund research on what you call “the astrophysicists problem” is important.

      • CB

        “I am merely reporting that this debate exists.”

        The debate about the existence of the sun?

        Yeah, not really.

        This is a propaganda outlet for the fossil fuel industry.

        If you are not a prostitute for that industry, why are you posting here instead of a peer-reviewed journal?

        “CFACT has received over $4.1 million in funds from Donor’s Trust and Donor’s Capital Fund between 2002-2011, plus an additional $582,000 from ExxonMobil between 1998-2012”

    • cshorey

      Mnestheus, do realize the level of crazy you’re dealing with in David Wojick. His main argument is that we can’t measure global average temperature and he ignores when people tell him we measure temperature anomalies as they are easier to work with. But try to match that idea with this article he’s written when he now praises an anonymous source “Javier” who says there are correlations between solar output and global temperature. David can have everything go his way because he’s lost his objective edge and thus any scientific credibility.

      • David Wojick

        Indeed Shorey, there is presently no instrument that measures global average surface temperatures. See my

        We do have instruments that measure something relatively close to global average atmospheric temperatures, namely the satellites. They tell us that the surface temperature computer models (which are not instruments) are wrong. Nothing crazy about it.

        • cshorey

          Satellites measure a voltage. That voltage is interpreted as IR photons hitting the detector. That approximation is then put through a MODEL to get temperature and is getting its photons from the mid troposphere to the upper stratosphere. Orbit and instrument decay must be corrected for (so hard to send people to up check and repair those things, right Dave). The irony is not lost on me that you whine about models, but jump to the first model you think supports your case. You reveal your inability to be unbiased when you get all hot for satellites while throwing away direct temperature measurements.
          Again, I bet you can’t measure the average temperature of your body, but you can tell by local temperature anomalies when you have a fever. I have lost all respect for you David. You’re a tired old hack sitting on his CFACT porch yelling at the kids across the street to get off his lawn.

  • cshorey

    Funny that you have to make sure to only look at data before the 1980’s to get the solar control story. Ever since then the two have been decoupled. It would be dishonest to imply that pre 1980 is the same as post, as this article and its sources have. Not a single mention from any of them that an increase in solar radiation would cause a warming of the Stratosphere and Troposphere but what we observe is warming Troposphere and cooling Stratosphere overall, just what a greenhouse gas forcing would produce (it’s called fingerprinting – we can actually eliminate the Sun as a principal modern cause because the fingerprint goes the other way). And if this article is trying to say that the Sun creates cosmic rays that influence climate, that is a very weak link. Svensmark has directly stated that the aerosols produced in his CERN experiments are too small to act as cloud nuclei, thus killing one of CFACT’s favorite science distortions.

    • David Wojick

      The Climate Etc. article is not about mechanisms so as usual I do not see what you are getting at. You might try addressing what is said.

      • cshorey

        I directly say to the Climate Etc. article that the correlation breaks down after the 80’s, so sorry David, I did directly address what was being said. Pay attention. The point is that all those predictions and retrodictions saying human influence pulled out of the natural background influences in the 1980’s would mean ignoring the last few decades of decoupled solar/climate signal kills “javier’s” argument.

        • David Wojick

          Please point to he place in Javier’s article that you are responding to. I have no idea what you mean by “the correlation.” He talks about a lot of different correlations.

          • cshorey

            Goodness, this isn’t that hard. Everything after the 1980’s when the correlation breaks down between one measure of the climate shift (atmospheric temperature anomalies) and the Sun. But then there is a breakdown with all the climate shifts and the Sun after that. If the Sun were causing a warming, which you mistakenly think can’t even be detected, then it would cause a warming of all the layers of the atmosphere. Instead we measure a warming of the Troposphere and a cooling of the Stratosphere, which is exactly what was predicted for a greenhouse gas warming. Javier can show all the correlations before 1980 he/she wants and it doesn’t touch the fact that after the 1980’s those correlations break down. That’s the part of Javier’s argument I’m directly addressing yet again.

            • David Wojick

              I now assume that you are talking about the sunspot to temperature correlation. But this has been well known for over 20 years so the sun-climate researchers are well aware of it. The most it shows is that there is not a simple linear relationship, which no one claims.

              In fact your argument is what I call alarmist boilerplate, as it is said often but means nothing. Even worse the supposed lack of correlation is between sunspot numbers and the unreliable output from the surface temperature statistical models, which show steady warming after 1980. As I have pointed out before, the satellites show no such warming. So maybe the correlation is better than thought.

              As for stratospheric cooling, you are here assuming a strawman sun-climate mechanism simply in order to falsify it. A common fallacy. Have you actually looked at any of the sun-climate research?

              • cshorey

                You don’t have to assume it David, Javier gave links to the papers he was using to make the correlations as he didn’t collect the data himself of course, and those papers are sunspot correlation papers. But today we also have direct measurements of solar output and the magnetic field strengths of the Earth and Sun. When the sun puts out more energy it puts out more visible (warming the surface and thus the troposphere) and UV (warming the stratosphere ~ozone layer). This would cause warming of both layers as the Sun’s output increased. But what we observe is a cooling stratosphere just as Smagorinsky and Manabe predicted decades ago, and has been a robust signal in climate science. There is no solar forcing mechanism that warms the troposphere and cools the stratosphere. Yes, I believe I’ve looked at more sun-climate research than you have. None of your responses have touched the issue that all sun-climate correlations broke down after the 1980’s.

  • MichaelR

    “There is a lot of debate about the sun’s role in global warming and climate change. Some scientists argue that the sun plays the dominant role, making human activity insignificant.”

    This is factually incorrect. The action of the sun is well understood and of course it’s variability is factored into models of warming. Indeed it is one of the climate sceptics’ favourite tricks to look at temperature vs CO2 over the last 500million years and point to the lack of direct correlation, which is because THEY are ignoring the warming sun over that period!

    The fact that’s solar output as TSI has been static or falling since the early 1970s makes it impossible to argue that increased solar activity has caused the very significant warming in that same period.

    Stop trotting out this bullshit assertion. There is no empirical evidence to support it. In fact the evidence obviously goes against the sun as the driver of recent warming, whereas GHGs and primarily CO2 explain it very well.

    • David Wojick

      You need to go argue with Javier, not with me. But it is widely recognized that TSI is not the issue. The research is focused on other variables and mechanisms, which are certainly not well understood.

      • MichaelR

        By “not well understood” I think it would be more accurate to say that they have not been robustly demonstrated to be causing significant warming compared with GHGs and known feedback effects. There are a handful of respectable papers that have tried to analyse the action of cosmic rays on the atmosphere but none come within a mile of explaining the past and present behaviour of the atmosphere as well as the established science that is built into the IPDC models.

        The way you are positing these “not well understood” mechanisms suggests that “Jeez, if only we could figure out why this warming is happening gosh darn it, but these mysterious actions of the sun are just so tricky.” But that is nonsense. We know more than enough to know for a fact that man made CO2 is responsible for current warming and that minimising that warming will rely on minimising future emissions.

        There is of course research to do around the margins and we will surely come to understand it all with more precision in time but FFS, can we stop inspecting the cutlery while the Titanic goes down here. We don’t get another shot at this. If we F up our atmosphere it will be for all intents and purposes irreversible and our generation will go down in human history as the fuckwits who watched it happen. That will have cause greater damage to the future of mankind and our biosphere than anything we have managed to screw up thus far. I really don’t want to die in a world that is a shit show compared to when I was born because of stupid ideological arguments about settled science like this. That would be the ultimate tragedy for all our lives and those of our descendants.

        • David Wojick

          There is certainly no robust demonstration that CO2 is causing the current warming. In fact there is no evidence of CO2 doing anything in the entire 40 year satellite record of atmospheric temperatures. What little warming there is is entirely coincident with two big El Ninos.

          Actually it is coincident with the 1998+ ENSO. We will have to wait a few years to see if the latest El Nino has caused a warming step up, like the first one did. But even if it does, there is still no sign of significant GHG warming.

          Beyond that you must either explain or explain away the considerable evidence that Javier presents. If you mean by no robust demonstration that there is as yet no explanation for these remarkable correlations, that is precisely his point.

          • MichaelR

            “There is certainly no robust demonstration that CO2 is causing the current warming. In fact there is no evidence of CO2 doing anything in the entire 40 year satellite record of atmospheric temperatures.”

            You know that is a lie. There are literally 1000s of papers that draw this exact conclusion. The mechanism for CO2 as a GHG has been understood since the 19th century. It’s impact on the climate in past climate is well attested to in multiple fields of research.

            “What little warming there is is entirely coincident with two big El Ninos.”

            El Ninos/La Nina are cycles lasting around 7-10 years. Cycles means they COME and then GO so how can they possible be responsible for 0.7 degrees net trend warming since the early 70s?

            And if Javier’s work is so groundbreaking, why is it not published in a well reputed academic journal? You should know the general quality of dross that is found on blog sites masquerading as peer reviewed science. Javier’s research is MEANINGLESS until it undergoes peer review, publication and the opportunity for other groups to refute it. That is what real science has to go through to ensure it’s robust.

            Your qualification is in epistemology. You have no formal training in climate science but you should at the very least understand how the system of publication in esteemed peer reviewed journals has allowed mankind to build up a robust canon of reliable scientific knowledge, free from biased and flimsy claptrap. You should not be expounding views that a) categorically deny well established science and b) push forward work that has not met any burden of review, publication or been subject to testing by replication post such publication by other groups.

            I don’t like to get ad hominem but as someone concerned about how we can know what we know in science, and how flagrantly you are subverting that with your stated views here, I can only imagine that you do it because you are under some kind of delusion of because the money is good…

            • David Wojick

              El Ninos and La Ninas are relatively brief major changes in Pacific ocean circulation. According to the satellite record there was little or no atmospheric warming from its beginning in 1978 until the giant El Nino struck in 1998. Once that ENSO subsided there was again no significant warming, until the recent big El Nino struck.

              However, the second period of no warming was warmer than the first period, presumably due to the giant El Nino. There is no evidence of any GHG warming in this entire record. What the recent El Nino will bring remains to be seen and it will take several years to find out.

              What is truly sad is that there are thousands of papers trying to explain the supposed surface warming, estimated by the surface temperature computer models. The reality is that warming probably never happened, so science is working hard to explain what simply does not exist.

              • MichaelR

                Why do I have to state the bleeding obvious here? El Niño events are part of a cycle. They drive the surface temperature up for a while, then as the cycle reverses then their surface warming effect reverses. That is what a cycle means. The cycle just transfers energy from the deep ocean to the upper ocean atmosphere, but then the cycle reverses, cooling the surface again.

                So they don’t cause net warming as you seem to imply. In fact you certainly could not even assert that they do (ie that the atmosphere and ocean surface are warming long term while the deep ocean cools long term) as the deep ocean is also warming significantly.

                And to say that there has been no warming since 1978 is nonsense as you well know. All the data shows marked warming.

                • David Wojick

                  Michael, did you even read what I said? For example, I never said there was no warming since 1978, quite the contrary. Plus you have given a link to a surface temperature computer model output, when I specifically referenced the satellite record. These surface models are no good.

                  Maybe read it again and this time think about it. Here is the satellite record for the lower atmosphere:

                  The step up in average temperature that follows the giant El Nino is pretty obvious once you look for it. The second big El Nino peaks in 2016.

                  • MichaelR

                    First, in what paper are the computer modelled reconstructions dismissed as you seem to want to above? UAH is just one dataset of one part of the atmosphere. There are others that are also valid and should be accounted for to get a total picture of the global atmospheric temperature.

                    Also, even in that set, you can see it as a clean warming trend. Sure there is a big perturbation in the middle but that does not mean that the perturbation CAUSED the trend.

                    Besides, you can not argue that the ocean has lost energy to the atmosphere long term post this event as the ocean temperatures IS STILL RISING as well.

                    Surface Temp courtesy of the EPA

                    Overall energy absorption courtesy of a write up on a paper in Climate Dynamics (a journal which IS on the MJL with a respectable impact score of 4.7]

                    So to try to make out that ocean cycles are dumping energy into the atmosphere and there is no net energy increase is crap. The oceans are absorbing huge amounts of energy AND the atmosphere is warming significantly as well.

                    The former fact is one of the reasons scientists are so worried about huge ice sheets on the Antarctic coast that are being undermined by warming waters. And if they break off, they will reveal huge towering cliffs of land ice that will be completely unstable and start a runaway collapse and melt of currently land ice.
                    Even a deliberately sceptical write up of the same work does not detract from the scale of the danger here.

                    Essentially scientists are being circumspect and say “yes, it’s definitely a big problem but we aren’t sure exactly when it’s going to happen”. No one is saying “no this is all centuries off if it is a problem at all”, sadly.

                    Anyway back on topic, it’s clearly nonsense to suggest that the surface warming is a function of an energy dump from the ocean that will reverse. It won’t reverse. The whole system is warming, thanks to man made GHGs as 1000s of papers agree.

                    • socalpa

                      Quite a speech !
                      The problem for you is ,that similar warming and cooling periods occurred since 1700 CE . ~200 years before any significant rise in CO2 .Then , after 1875 temps declined to near the lowest of the Holocene as CO2 rose .
                      Your ignoring of the impact of large scale multi decade ocean currents like AMO and PIO is silly . These are long recognized drivers of surface temps .In fact ,it was recently found Arctic sea ice extent was driven by AMOC phase ,not ghgs .
                      And NASA reported Antarctica ( 90% of global ice) increasing in both continental (jand ice) and sea ice for decades .
                      You mistake your opinions of what the science and data shows for facts .
                      And your pointless hostility is tiresome .

                    • MichaelR

                      You have made some quite specific assertions there. So I expect you can cite journal papers to support then right? Please could you link to them?

                      Just re the Antarctic ice, you know that that is only half the picture. The Greenland ice shelf if melting much faster than ice on Antarcticais being accumulated. The last numbers I saw has a NET melt of land ice of 160 billion tonnes per year.

                      If I am “hostile” it’s because I find it tiresome when climate change sceptics repeatedly and deliberately misrepresent science to suit their agenda, as you demonstrated with the ice sheet melt figures above.

                    • socalpa

                      And , another speech ?

    • socalpa

      That is what was believed the cause of Arctic ice retreat observed 1980-2005 .CO2 was claimed driver .
      Turns out , the AMOC ocean current positive phase was the culprit, that ended and now the Arctic projected to have stable to increasing ice cover next decade(s) ;
      And, the Solar Activity was highest in over a century in cycles peaking 1960s – 1990s.
      The oceans are redistributing that heat , and you ignore the thermal inertia of the oceans as well as the fact that water vapor is the dominant forcing for surface heat retention over open oceans at > 90% and Insolation the energy that warms the oceans to begin with as oceans surfaces are opaque to IR . SW (solar irradiance) penetrates hundreds of meters .

  • socalpa

    It seems a little ridiculous that Sols’ role in climate change has been so greatly ignored . More than ridiculous , really makes one suspicious of the motives of those that seek to downplay the source of 99.99% of energy to the Earths atmosphere and oceans .
    The source that along with water vapor melted back mile thick icesheets across about 1/3 of the northern hemisphere and about 1/4 of the southern hemisphere thousands of years before any significant rise in CO2 .. and each season today , causes a 100F temp range to occur in the mid and north latitudes .
    The effects of low solar activity (Solar Grand Minima) show long cooling periods occurring as a result . Such the Little Ice Age which began with the Wolf Minima and ended with the Dalton after reaching the lowest temps of the Holocene during the Maunder Minimum 1650 -1715 .
    In fact ,we may be seeing the onset of one now as the warming effects of the highest solar activity in over a century in cycles 1960-1990s fades .warming recently explained by the thermal inertia of the oceans as well oscillations of the major currents redistributing heat from prior ,higher solar cycles .