To get the music out of the way at once, I first heard this George Harrison song when Nina Simone sang it. In fact, this post is about the influence of the Sun on the climate of the Earth, a subject I wrote about at the end of the year. The post received a good deal of comment, and some of the comments forced me to go and do much more reading and thinking. And the more I read the richer the subject became. So what I have written here is only a short and superficial guide to a major area of research.

No matter, even the IPCC is coming to the view, reluctantly and with some hedging, that it has underestimated the role of the Sun. The WG1 volume of the 5th Assessment report has this to say, in the context of the pause: The observed reduction in warming trend over the period 1998–2012 as compared to the period 1951–2012, is due in roughly equal measure to a cooling contribution from internal variability and a reduced trend in radiative forcing (medium confidence). The reduced trend in radiative forcing is primarily due to volcanic eruptions and the downward phase of the current solar cycle.

There is something odd about this, as we haven’t had much in the way of volcanic incidents in that 14 year period, and if solar activity (= sun-spots) are not of much power, as is the IPCC’s position(see the comments at the post I cited above) then how can they be a cause of the ‘pause’? If you want more of this, then go to Willis Eschenbach’s recent erudite post at WUWT, from which I took the IPCC quote.

I only saw that post a day or so ago, but the reading I have been doing has taken me to an excellent review article by Richard Mackey, ‘The Sun’s role in regulating the Earth’s climate’ published recently in the Journal of Energy and Environment paper (VOLUME 20 No. 1 2009).  This is no quick read, because it is fifty pages long and refers to nearly 150 articles. But to read it, and I’ve now done so twice, is to enter a completely different world than the one in which carbon dioxide is thought to be the ‘control knob’ of the Earth’s climate.The solar physicists seem to be pretty sure that they can explain a good deal of the apparent warming over the last century, though you don’t hear about this in the mainstream media, and there’s nothing much about it in the IPCC reports.

What they are talking about is not simply sunshine, or ‘total solar irradiance’, but other aspects of the Sun/Earth relationship, including the movement of the planets and the Moon (the tides being the result of the joint effects of the Sun and the Moon), the effects of the Sun’s electro-magnetic field, the solar wind, the occasional burst of matter (mainly electrons or protons), and the inter-relationships between all these variables — which can be more significant still. We need to remember, because it is not obvious from the way we see the Sun, that it is incomparably larger than our planet: about 1,300,000 times bigger in terms of relative volume. Almost anything that happens in the Sun can have an effect on us, especially in terms of climate.

We can’t predict at all well, however. The relationships I mentioned are unstable over time. Yes, we can find patterns and regularities (and there are lots of them), but they do not work like clocks, and we do not by any means wholly understand them. Nonetheless, Gerard Bond, the American astronomer who gave his name to Bond events (see the great chart on human history since the ice age) has claimed that ‘The Earth’s climate system is highly sensitive to extremely weak perturbations in the Sun’s energy output …’ 

Others claim that ENSO events are largely regulated by total solar variability (sun-spots again) and that El Nino events occur twice in each solar cycle, one each in the ascending and descending phases of each cycle — and that solar wind variations precede El Nino events by 15/16 months. There seems no doubt that during solar maxima the Earth warms up and during solar minima it cools down — and the the planet does so everywhere.

Why is it so? There are hypotheses of all kinds. What we have are observations in need of explanation, not computer models offering confident answers. It is fascinating stuff. How about the Length of the Day, the measure of the Earth’s rotation around its axis? Every ten years or so the Earth rotates a little faster or slower –speeding up a little over one decade and slowing down a bit over the following one.  Long ago, it was shown that the speeding-up brings on global warming after about six years; the slowing down brings on global-cooling. I’ve started on a new knowledge avenue in global warming, one that I knew nothing about whatever when I started to read about climate six years ago. And I’ll continue along it.

To finish: Mackey’s review article was published in 2009, and even then, five years ago, the consensus among the solar physicists was that we were pretty likely to experience a long period of cooling. Well, the evidence so far is that their conclusion was right —it is plain, at least, that average temperatures are not rising in harmony with carbon dioxide accumulations. I keep having to remember that the sun is really much more powerful than we think — and that, as with other aspects of ‘climate change’, we have a lot more to learn.

[updated 23 January 2014 to provide a better link to Mackey’s paper, a copy of which any reader can get from me by emailing me at <> — the journal wants a lot of money for it!]

Join the discussion 12 Comments

  • Mike O'Ceirin says:

    An excellent post thank you. I have always found it amazing that the warmists can contend the sun has insignificant influence on variability. If it sneezes surely we are going to get a cold.

    It seems according to the BOM and CSIRO that what you write about has no effect on Australia, somehow we are getting warmer while the rest of the world stays the same! Currently according to the ABC and the Greens we are experiencing an Abbottwave caused by wishing to repeal the carbon tax.

    • John morland says:

      I recall a NASA news update in early 2013 mentioning future climate models should consider more emphasis on solar variability.

  • BoyfromTottenham says:

    Hi Don,

    A thought-provoking article, as usual. I started looking into the AGW thing a few years ago and was gobsmacked when I entered ‘sunspots’ into the search field on the BOM website and got a response like ‘the Bureau does not research sunspot activity’! I am familiar with Willis’ excellennt articles at WUWT, and occasionally comment there. You may be interested in this new article by Tim Cullen that proposes another (extra-solar) influence on our climate: When will there be enough evidence that our climate is mostly influenced by ‘natural’ vs ‘human’ causes to cause our leaders to question the whole IPCC paradigm of ignoring ‘natural’ causes?

  • PeterE says:

    Thanks. Most interesting.

  • Peter Donnan says:

    You conclude, Don, that ‘average temperatures are not rising in harmony with carbon dioxide accumulations’. Despite stifling conditions at the Australian Tennis Open today and a predicted hottie of 41 degrees locally, Darwin is cool and Canberra is likely to be so again next week: the key point is what is happening at a global level and you cite evidence that supports your conclusion.

    Ian Chubb, a former fellow VC and well known to you, writes today in ‘The Australian’ that “….we know that as CO2 levels in the atmosphere increase, so too does the amount of CO2 absorbed by the ocean, with the effect of making the water less alkaline (or more acid). Why would we presume that would have no effect on marine life? We also know that the heat content of the oceans has increased consistently although the rise in atmospheric temperature recently is flatter. Why would we presume no effect on the currents, winds and evaporation, and a subsequent impact on climate?”

    He makes some interesting observations about the debate around climate change and notes that it sometimes assumes a ‘low grade’, personalised dimension that is not helpful. He recognised how complex climate matters are and that CO2 does have a positive role in the atmosphere although although not in the quantities that are presently there.

    A key point made by Ian Chubb, and one that many non-scientific people such as myself tend to assume, is that the link between CO2 levels and its impacts on climate is a linear one; it is non-linear.

    More than 20 years ago now, I viewed a computer simulation model about detrimental processes that led to soil degradation, rising water table etc which finally over a decade appeared on the surface and made the ground unworkable in terms of growing crops etc. The moral of that program was that unless the farmer adopted different soil practices etc by the time the effects appeared at ground level, it was too late. In Egypt today, there is still land that is unusable because of unnatural irrigation practices adopted by ancient Egyptians.

    Many people who are interested in climate change accept that the levels of CO2 emissions are a concern but the key questions are: do we remain confident because present temperatures are not raising in harmony with them? Should there be systemic and political strategies to address them on a global basis because in time they will affect us all, as Brian Schmidt and many other scientists believe? Is it possible that although in the short term of the next ten to fifteen years temperatures may not be impacted but that a tipping point is reached where the process is almost irreversible because of past neglect? Is it the case, perhaps as Maurice Newmann, believes, that it is all a huge myth? Clearly this is a high-stakes debate.

  • margaret says:

    Adding to the erudite conversation, you can’t dismiss the music THAT easily! – Here Comes the Sun is a terrific song by my favourite Beatle. Haven’t heard the Nina Simone version.

  • DaveW says:

    The ‘excellent review article’ link didn’t work for me – 404 error

    Gympie, Qld, allegedly set a new record a week or two ago +42.1 and Edmonton, Alberta, a new high of +9 yesterday. I suppose the same sun shines on both cities, but I find it very confusing now that both record high and record low and everything in between are caused by that satanic CO2.

  • David says:


    1. The Journal Energy and Environment has very impact factor.

    “…87th out of 90 journals in the category “Environmental Studies”.

    2. Although the article was published in 2009 but has only been cited twice! (see Google scholar)

    3. The article presents no original empirical evidence to support the author’s claims.

    4. Presents a punishing 70 page review of the literature, with no explanation as to how the various articles were selected for inclusion.

    I notice also in a submission to the “Garnaut Climate Change Review”$File/D08%2030154%20General%20Submission%20-%20Richard%20Mackey.pdf

    that Mackey recommended that,

    “The [Garnaut] Review should invite distinguished Australians with relevant expertise to present papers on these topics and invite members of the public to lodge submissions, as well.”

    And then helpfully suggests in a footnote

    “For example, the Review might invite Don Aitkin, Professors Bob Carter, Ian Plimer and Stewart Franks and Mr John McLean to be the lead participants of the workshop.

    Good mate of yours is he Don? 🙂

    I’m sorry Don but this article fails to meet minimum requirements.

    • David says:

      First line should read

      1. The Journal Energy and Environment has very LOW impact factor.

    • Don Aitkin says:

      I’ve met him once, at a concert, though I have great respect for his knowledge in this field.

      I take very little notice of impact factors. Do you know what a review article is? You review the work of others. Do you have an objection to any aspect of the substance of the article? What are the minimum requirements you speak of? Where can I find out about them?

      • David says:


        This is what I look for in a literature review.

        If the author has a Noble prize in the CV, like Brian
        Schmidt for example, then I am happy to read their fire side chat; allowing the author to cherry pick the literature as they see fit. But if they are a Norrie Nobody and they want to construct an argument based on a summary of the literature alone, then I want to see some inclusion/exclusion criteria. Failing that, I will want to see analysis of a dataset to test their conclusions.

        Well I do look at impact factors. A 5 year old literature
        review published journal ranked 87/90, which has only received 2 citations, is not very impressive. Not even the other sceptics have bothered to cite it.
        Minimum requirement’s
        * 5 citations
        * In at least a B grade journal

Leave a Reply