The Hottest Year, but NOT due to Greenhouse Warming

ACORN-SAT- the gift that keeps on giving!

Unfortunately for doomsayers, the fact that 2013 was the hottest year on record in Australia is no evidence for the effects of greenhouse warming.  In fact, it is the very opposite.

Why?  Any sort of warming will eventually produce the hottest year on record.  But warming due to the enhanced greenhouse effect is quite special.  Warming due to greenhouse gases is evidenced by

greater warming of night time temperatures than daytime temperatures”

amongst other things, according to Dr Karl Braganza (

I discussed this in April  last year.  Now, with the updated data for 2013, it’s time for a reality check to see whether there is now evidence of greenhouse warming in Australia (a region as large as Antarctica, Greenland, the USA, or Europe, and supposed to be especially vulnerable to the effects of global warming.)

Once again I am using data straight from the Bureau’s website.

Fig. 1: Monthly maxima and minima with 12 month smoothing, December 1978 – December 2013, from

max v min linear

For the past 35 years, there is much LESS warming of night time temperatures than daytime temperatures.  And the divergence is increasing:

Fig 2: fitted with a 2nd order polynomialmax v min poly

Sorry, but this is not evidence of greenhouse warming over the period of the satellite era, when greenhouse gases have been increasing rapidly.  It is merely evidence of warming.

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23 Responses to “The Hottest Year, but NOT due to Greenhouse Warming”

  1. Deadman Says:

    I dispute “the fact that 2013 was the hottest year on record in Australia”; that is true only if (a) we consider the records since the 1930s—ignoring measurements from a century earlier—and (b) if we accept the fudged, manipulated, dishonest figures supplied by the BoM and other, warmist, sources.

  2. Chuck L Says:

    More likely to be evidence of less cloudiness related to ocean cycles and solar cycles. There are a number of new studies suggesting these linkages.

  3. barry Says:

    We have global solar data for the satellite period (and before). No increase of solar intensity is seen since the mid 20th century.



    The current peak of solar intensity is the lowest in 80 years.

    It aint the sun.

    Anyone up for plotting cloudiness and ocean cycles?

    • kenskingdom Says:

      “It aint the sun”. So the “pause” in global warming is not due to lower solar intensity- I thought that was the current excuse. Maybe there’s a link between solar/ clouds/ ocean cycles. Time will tell. And never would I say a hot year was due to a hotter sun or vice versa.

      • barry Says:

        “Excuse” – is there a need for such rhetoric?

        The solar low is incidental. Solar intensity and temperatures have been diverging for 60 years. The heat budget isn’t just surface temperatures, and the prevailing explanation for the ~16 year lull in surface temperatures is heat transfer to the oceans. Ocean heat content in the 0 – 750 meter strata, and also in the 0 – 2000 meter volume has been increasing during the ‘pause’. Global sea ice and glaciers have receded, too.

        Maybe there’s a link between the factors you suggest, but it’s largely speculative, and efforts to link them have relied on curve-fitting without a robust determination of the physical mechanisms.

        2013 was a record-breaker for solar exposure across the country. While this almost certainly contributed to unusually hot temps nationally, I agree with you that attributing a dominant cause for one year’s temperature is next to impossible.

        • kenskingdom Says:

          Barry, perhaps you should seek information beyond what Skeptical Science gives you. Maybe a first step would be checking current and recent sea ice data, and then perhaps considering whether the “prevailing explanation” is not speculative as well in the light of quantity and quality of data, not to mention mechanism. And besides volcanic activity and random meteorites, the vast bulk of the energy reaching the earth IS from the sun, so saying “It aint the sun” is premature. Anyway this is getting off the track, so we may have to agree to disagree.

  4. barry Says:

    Daytime cloudiness since 1957.

    I’ve been chatting online with someone at SkS about the 2013 record-breaker, and they pointed out that solar exposure (total solar radiation energy at the surface) has been a record for that year. But the major control knob on solar exposure is cloudiness. The long-term trend is slightly upwards, so according to his hypothesis Australia should have been getting cooler from 1957. But clouds also impede upwelling radiation, causing warming at the surface. We’d get a better picture if there was data available for low-level and high level clouds. Low level clouds tend to reflect solar radiation, while the high-level clouds tend to trap upwelling infrared.

    The diurnal trend globally has been flat for the last 30 years or so. But if you start earlier, the global trend is negative. In terms of assessing global warming causes from diurnal trend, I don’t think extrapolating from one region of the planet is sound. Different regions exhibit different DTR trends (negative and positive). As for the last 3 decades globally, min/max temps have more variability than mean temps, so perhaps you need longer periods to get statistically significant results than for mean global temps. I don’t know the answer, but there are a few studies on global diurnal range for the last 30 years, eg

    • kenskingdom Says:

      Hi Barry, this was a long time in the filter!
      Yes I certainly agree with everything you’ve said, (mostly). I am well aware of the link between DTR and wet periods including cloudiness and the effect on maxima especially of daytime cloud. It would be much better if we had data for night time cloud as well, which combined with high levels of liquid and vapour H2O, and frequently more and greener vegetation (but not always), gives rise to much higher night time temperatures.
      I do not extrapolate from Australia to the rest of the planet, but several papers you mention in the DTR thread focus on regions such as Europe and Canada. I try to do the same for Australia, and query the reason for the discussion void. As for longer periods, the 80 years for SE Australia should be adequate surely.

    • kenskingdom Says:

      PS- seasonal cloudiness vs DTR might show interesting regional trends. I can feel a post coming on…

      • barry Says:

        Good show! Thanks for clearing my posts.

      • barry Says:

        Checked daytime cloudiness at BoM. The trend is up since the late 1950s. But that’s not the whole story. Low-level clouds generally increase reflection of solar radiation, while high-level clouds generally retard upwelling infrared radiation. BoM doesn’t provide data (that I know of) that discriminates. There is still significant uncertainty regarding the effect of long-term cloudiness changes on temperatures.

  5. barry Says:

    Doh, I’ve repeated myself. Too many conversations at once.

    As for longer periods, the 80 years for SE Australia should be adequate surely.

    Adequate for what? Regional results are not adequate proxies for global, nor does a divergence in regional or more localised data prove much beyond what is already known. Localised data varies across the globe. We should not automatically conflate past local attribution with future vulnerability in regions in isolation from global observations.

    • kenskingdom Says:

      OK, try 67 years for Australia as a whole. Adequate for showing climate is varied, regional, and in Australia doing things that are not reported by BOM. So while BOM and CSIRO and Co. persist with their claims such as “The Australian region warming is very similar to that seen at the global scale, and the past year emphasises that the warming trend continues. As summarised in the recent Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, recent warming trends have been dominated by the influence of increasing greenhouse gases and the enhanced greenhouse effect” when the evidence for the Australian region is that for 67 years there has been no decline in DTR, one of the key indicators of the enhanced greenhouse effect, I will persist in publicising this.

      • barry Says:

        Nothing wrong with publicizing your results, but aren’t you conflating regional effects with global here? Over the past 67 years mean temps for some locations/areas of the globe have cooled, but overall it’s been warming. Same for DTR – different results in different places, but global average temps show negative DTR for that period. Antarctic sea ice has been growing while the arctic ice has receded for the satellite period. But global sea ice extent is down.

        The latter point is a good proxy for other regional variability. Dynamics in the Arctic and Antarctic are different, with opposite results. While Antarctic sea ice gain is not a foolproof argument against AGW, it does call most projections into question for that region.

        I know your focus is Australian weather and climate, but I think you’d make a better case looking at global DTR for the last 30 years, where there is no trend. That isn’t much publicized and is a stronger (but also not foolproof) argument against AGW.

  6. barry Says:

    Maybe there’s a link between solar/ clouds/ ocean cycles.

    Hardly an exhaustive analysis, but I ginned up a graph at woodfortrees comparing two different warming periods – 1910-1945, and 1979-2013. Periods selected because the temperature trends are statistically significant, the periods are of similar duration, and the rate of warming is comparable.


    I had to extent the solar trend period for the earlier period of warming in order to match phases (solar cycle peak to peak). For both periods I selected the PDO oscillation because it is almost certainly connected to ENSO and because ENSO is the ocean oscillation with greatest impact on Australia.

    The PDO trend for each period is neutral, but the solar trend is opposite in sign. A cursory look suggests that there is no link between solar/ocean cycle interactions to cause warming in Australia. Heavy caveats, of course, are applied.

    Even if I managed to fiddle with start/end dates to get a better fit for the curves, a physical mechanism linking solar cycle/cosmic rays and clouds has yet to be definitively established. The proposed connection remains highly speculative, here and in the scientific literature.

    • kenskingdom Says:

      Heavy caveats indeed. Linear trends of PDO through those periods completely obscure what the PDO was actually doing, e.g. in the first “flat” period, swinging from mildly positive to mildly negative to strongly positive to strongly negative (lowest being in the mid to late 1950s). Similarly since the mid 1970s. And solar influence is not totally dependent on sunspot number. As I said, “MAYBE” there’s a link, I wouldn’t bet my super on it, but I wouldn’t argue there’s none. Time and much research will tell.

  7. barry Says:

    Direct solar influence is also measured by satellite – total solar irradiance.


    As you can see, sunspots are an excellent proxy for TSI. The waves match. There is high confidence in this for the 11-year solar cycle.

    At the surface, solar exposure largely depends on clouds. But, a link between cloudiness and TSI/ocean atmosphere fluctuations is not established and, and isn’t apparent when comparing two periods of similar warming.

    “Maybe” is right.

    Ken, what drives you to speculate so hard that accentuated greenhouse warming is not happening? Even Anthony Watts, Roger Pielke Snr, John Christy, Roy Spencer and Richard Lindzen attest that there should be some warming from increased GHGs. Not to mention the physics. Is AGW really so unacceptable, or is your view more nuanced than that?

  8. kenskingdom Says:

    Clouds/ increased H2O feedback is the weak link in the theory that their contribution in the enhanced greenhouse effect – which I do understand and accept- will magnify the response to a doubling of CO2. I’m also aware of the long term context, showing a cooling trend (with ups and downs) since the Holocene Optimum. Of course there is a human contribution to the current warming phase (including but not limited to CO2). Of course there will be record temperatures in a warming phase when our observation period is so short.
    Call it my cranky gene (as my wife does). I am suspicious of pronouncements by “experts” and like to check things for myself.

  9. barry Says:

    Ok, thanks. It’s good to context on your approach.

    Climate sensitivity – the power of feedbacks – is surely uncertain. My approach, when I am no physicist, is to scour the literature to get a fix on the range of estimates and determine the mean values. I think I automatically clip outlying results. Hardly a foolproof method, but at least I’m not falling into my own confirmation bias trap while I educate myself, and I’m not judging beyond my abilities. “Skeptic, doubt thyself.”

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