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Wednesday, December 4, 2013

An eccentric speculates on a Dalton minimum by 2050

Sou | 2:45 AM Go to the first of 4 comments. Add a comment

Anthony Watts has dug up a paper about the sun (archived here).  Dr. H.S. Ahluwalia from the University of New Mexico in  the USA thinks he has seen a pattern in solar activity that he calls a three-cycle quasi-periodicity or TCQP.  Using his TCQP, he's predicting declining solar irradiance culminating in 2050 in a lull equivalent to the Dalton minimum, which occurred from the late 18th to the early 19th century.

I looked up "three-cycle quasi-periodicity" and it appears that about the only person who promotes this is HS Ahluwalia.

I did find it studied in another paper, by RP Kane in JGR.  Kane found no evidence of the three-cycle quasi-periodicity.  On the other hand, HS Ahluwalia is mentioned in a paper by Clilverd as successfully predicting solar cycle 23 using this cycle. (Back in 1998, HS Ahluwalia predicted in this paper that solar cycle 23 would have an annual mean sunspot number count of 119.3 ± 30 at the maximum.  According to Wikipedia, it was 120.8, which is almost spot on.)  Anyway, I don't know whether this pattern exists or not.  Solar specialist Leif Svalgard at WUWT says there is no evidence for it.


A little bit eccentric


The paper that Anthony Watts refers to is paywalled but I dug up what is probably a very similar paper from last year.  From reading that paper I'd say that HS Ahluwalia is a little bit eccentric.  The first part of the paper is all about solar activity and finding various patterns.  Toward the end of the paper, HS Ahluwalia launches into a mish-mash of a discussion that ranges from the IPCC and climate, through to volcanoes, inflation (of prices), human population projections, food prices, Thomas Malthus, wheat, rice and famine.

Since 2011 HS Ahluwalia seems to have been promoting the idea that there will be another Dalton Minimum in the middle of this century.  He also seems to be a climate contrarian.  In this conference paper in which I think he first promoted the idea, he makes reference to Akasofu.  And in the discussion section he once again drifts away from solar activity, this time to sea surface temperatures as well as food prices and other things.


The Dalton Minimum influence was not that great


Scientific research suggests that the Dalton minimum didn't have that much impact on global surface temperatures.  Although it coincided with a marked drop in temperature, most of that drop is attributed to volcanic activity, particularly that of Mount Tambora in Indonesia in 1816.  Below is a chart from the IPCC AR5 report, which shows the radiative forcings of solar, volcanic and well mixed greenhouse gases together with surface temperature.  Click the image to enlarge it.

Box TS-5 Figure 1 IPCC AR5 WG1


A grand solar minima would be barely noticed in global surface temperature


In regard to the impact of a relatively large reduction in incoming solar radiation, such as a Dalton Minimum, the chart above should give us a clue that it wouldn't have much effect.  In 2010, Feulner and Rahmstorf had a paper published with the title: "On the effect of a new grand minimum of solar activity on the future climate on Earth".  What they found was that even if there were a grand solar minimum this century it would only reduce surface temperatures at 2100 by 0.1 degree or 0.3 degrees at most, which would barely make a dent in the expected rise in temperature from greenhouse gas forcing (anything up to 4 degrees).


From the WUWT comments


Nothing of interest to see.  There was a bunfight and Anthony ended up banning one of the deniers - something he rarely does.  (Archived here.)

4 comments:

  1. I knew Mark Clilverd at BAS. He was in UASD, though.

    ReplyDelete
  2. When global warming gullibles can explain the warming and cooling cycles from 5000 up until 200 years ago when no CO2 on issue, then they might have a shred of credibility. Global cooling is now ON.

    ReplyDelete
    Replies
    1. Oddly enough, anonymous, they can. The limit is as always lack of good data, whereas for the current warming experiment, there's lots of data, and all of it proves that we're warming the planet at a rapid rate.

      Delete
    2. Dear Anon.

      Did you really mean "cycles"?

      Do you have data demonstrating that any such events were global and synchronous?

      Are you aware that nobody is arguing that CO2 was the only control on past climate change?

      Would you like to see a pretty picture showing why modern warming *isn't* caused by the sun? I've made one specially for you.

      And remember - past climate change happened because net forcing changed. Modern climate change is happening because net forcings are changing. Plus ça change...

      Delete

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