Sun said to be “bi-modal”
While many, including the IPCC, suggest the modern Grand Maximum of solar activity from 1950-2009 has nothing to do with the 0.4C global warming measured over that time frame, it does seem to be unique in the last three millennia.
from CO2 Science: A 3,000-Year Record of Solar Activity
What was done
According to Usoskin et al. (2014), the Sun “shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity records and of uncertainties related to long-term reconstructions.” Now, however, in an attempt to overcome such uncertainties, in a Letter to the Editor published in the journal Astronomy and Astrophysics, Usoskin et al. “present the first fully adjustment-free physical reconstruction of solar activity” covering the past 3,000 years, which record allowed them “to study different modes of solar activity at an unprecedented level of detail.”
What was learned
As illustrated in the figure below, the authors report there is “remarkable agreement” among the overlapping years of their reconstruction (solid black line) and the number of sunspots recorded from direct observations since 1610 (red line). Their reconstruction of solar activity also displays several “distinct features,” including several “well-defined Grand minima of solar activity, ca. 770 BC, 350 BC, 680 AD, 1050 AD, 1310 AD, 1470 AD, and 1680 AD,” as well as “the modern Grand maximum (which occurred during solar cycles 19-23, i.e., 1950-2009),” which they describe as “a rare or even unique event, in both magnitude and duration, in the past three millennia.”
Further statistical analysis of their reconstruction revealed the Sun operates in three distinct modes of activity – (1) a regular mode that “corresponds to moderate activity that varies in a relatively narrow band between sunspot numbers 20 and 67,” (2) a Grand minimum mode of reduced solar activity that “cannot be explained by random fluctuations of the regular mode” and which “is confirmed at a high confidence level,” and (3), a possible Grand maximum mode, but they say that “the low statistic does not allow us to firmly conclude on this, yet.”
What it means
Usoskin et al. (2014) write their results “provide important constraints for both dynamo models of Sun-like stars and investigations of possible solar influence on Earth’s climate.” They also illustrate the importance of improving the quality of such reconstructions, in light of the fact that previous reconstructions of this nature “did not reveal any clear signature of distinct modes” in solar activity.
Unfortunately, it was beyond the scope of this paper to address the potential impact of solar activity on climate. Yet the reconstruction leaves a very big question unanswered — What effect did the Grand maximum of solar activity that occurred between 1950 and 2009 have on Earth’s climate? As a “unique” and “rare” event in terms of both magnitude and duration, one would think a lot more time and effort would be spent by the IPCC and others in answering that question. Instead, IPCC scientists have conducted relatively few studies of the Sun’s influence on modern warming, assuming that the temperature influence of this rare and unique Grand maximum of solar activity, which has occurred only once in the past 3,000 years, is far inferior to the radiative power provided by the rising CO2 concentration of the Earth’s atmosphere.
Reference
Usoskin, I.G., Hulot, G., Gallet, Y., Roth, R., Licht, A., Joos, F., Kovaltsov, G.A., Thebault, E. and Khokhlov, A. 2014. Evidence for distinct modes of solar activity. Astronomy and Astrophysics 562: L10, doi: 10.1051/0004-6361/201423391.
Abstract
Aims. The Sun shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity records and of uncertainties related to long-term reconstructions. Here we present a new adjustment-free reconstruction of solar activity over three millennia and study its different modes.
Methods. We present a new adjustment-free, physical reconstruction of solar activity over the past three millennia, using the latest verified carbon cycle, 14C production, and archeomagnetic field models. This great improvement allowed us to study different modes of solar activity at an unprecedented level of details.
Results. The distribution of solar activity is clearly bi-modal, implying the existence of distinct modes of activity. The main regular activity mode corresponds to moderate activity that varies in a relatively narrow band between sunspot numbers 20 and 67. The existence of a separate Grand minimum mode with reduced solar activity, which cannot be explained by random fluctuations of the regular mode, is confirmed at a high confidence level. The possible existence of a separate Grand maximum mode is also suggested, but the statistics is too low to reach a confident conclusion.
Conclusions. The Sun is shown to operate in distinct modes – a main general mode, a Grand minimum mode corresponding to an inactive Sun, and a possible Grand maximum mode corresponding to an unusually active Sun. These results provide important constraints for both dynamo models of Sun-like stars and investigations of possible solar influence on Earth’s climate.
reasonable for “reseasonable”
An excellent volcanic stratospheric ice core reconstruction dating the occurrence and by extrapolation, the extent of solar insolation diminution when modeling temperature response. Note the sudden increase in volcanic stratospheric veiling aerosols during the entire LIA time span, which several climate scientists now consider to be a wider timespan than commonly believed.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0CDoQFjAD&url=http%3A%2F%2Fecite.utas.edu.au%2F81617%2F1%2FPlummer-2012%2520-%25202000-yr%2520LD%2520volcanics.pdf&ei=6KrnU7G5K4r7igKpx4CADA&usg=AFQjCNFvfH1iv6zD4FxE_oq_ZJm_gVv8nA
Pamela Gray says:
August 10, 2014 at 10:01 am
For the reasons I’ve repeatedly shown, totally ignored by you, your conjecture is unreasonable on its face. I did critique the one Team paper you presented to support your hypothesis. Tree rings might or might not record drought. They do not record temperature.
All the evidence is against your conjecture and not a shred of evidence supports it. Despite a VEI 6 eruption in 1257 and another in 1280, the period 1250 to 1300 was warmer than 1200 to 1250 and as warm as 1150 to 1200 in the CET, at least. And the following century was warmer than anything during the real LIA.
Even the Toba supervolcano eruption, two orders of magnitude greater than the 1257 event, had no discernible climatic effect. Best evidence now is that it might have affected weather for about six years.
You’ve got nothing, zip, zero, nada, zilch.
You haven’t even shown the Null Hypothesis false, ie there is no reason to think the LIA was any different from prior climate fluctuations, hence needs no special explanation such as volcanism.
Pamela Gray says:
August 10, 2014 at 10:46 am
The only “climate scientists” who imagine that the LIA started in 1257 are Mann and other Team members who want to get rid of the MWP, their bogus HS having failed to do so.
No legitimate climate scientist considers the LIA to have started during the warmest part of the MWP.
Leif Svalgaard says:
August 9, 2014 at 7:15 pm
I’m glad we’re in agreement.
There might be more on this blog and in climate studies in general if advocates for positions would begin by stating why the are convinced the Null Hypothesis is or isn’t satisfied.
Thanks for your input here and for amassing such an excellent collection of relevant research at your site.
My pure speculation on the temperature response is that scientists have not considered the discharge/recharge mechanism proposed by Bob Tisdale as a significant factor in global response to significant volcanic stratospheric veiling events. The usual explanation is that the overturning circulation is severally slowed, thus explaining the northern Europe’s plunge into cold due to the Gulf Stream slowing or stopping.
The speculation has to do with a lack of equatorial recharge thus eventually cooling the Earth’s oceans even though the over-turning circulation continues. I consider that the over-turning circulation must continue under my speculative suggestion in order for these less-charged equatorial waters to travel to extra tropical land masses, where that cooled temperature creates a weather pattern variation regime shift and that is only slowly recovered from as the veil clears and evaporation ends, leading to La Nina clear sky conditions sufficient to recharge the equatorial ocean once again. I credit Bob Tisdale’s thoughts on the discharge/recharge El Nino/La Nina process he proposes, though the extrapolation to LIA triggers is my own.
Sturgis:
Pamela Gray says:
August 10, 2014 at 10:01 am
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0CEYQFjAF&url=http%3A%2F%2Fwww.geos.ed.ac.uk%2Fhomes%2Ftcrowley%2Fcrowley_PAGESnote_volcanism.pdf&ei=dKHnU6XXEKLUiwLDuYDIDA&usg=AFQjCNFMeYdd9z2d-lptY0r18M85yaurSw&bvm=bv.72676100,d.cGE
Read the first sentence in the paper I linked to. The literature is replete with references to the beginnings of the LIA and the 1257 explosion. Have the argument with those papers and the growing list of climate researchers.
Pamela Gray says:
August 10, 2014 at 10:55 am
There is no temperature response. The period after both late 13th century eruptions was globally warmer, not cooler. Why is that so hard for you to grasp? Nor is there any evidence from ENSO records to support your physically impossible conjecture.
Pamela Gray says:
August 10, 2014 at 11:01 am
When are you going to start reading the material you link? The paper you linked asserts without basis that the LIA began in 1250, but there are zero actual temperature proxy data supporting that assertion, pushed by the Team. If you imagine that such data exist, by all means present them. You won’t because you can’t. No such data set exists. All show the 13th century warmer not only than the LIA (by a lot) but even the 20th century.
But the body of the work clearly shows only temporary, ie weather, effects from the eruptions it considers during the real LIA, ie in the 17th to 19th centuries. Note that chart (Fig 2) doesn’t include the 13th, 14th or 15th centuries, starting in 1630. And its Fig 1 runs from 1800 to 2000.
None of the five references does as you claim. Not a single one makes the case for a climatic effect from volcanic eruptions, just noting the temporary (a few years at most) effect on temperature.
You still have nothing. If you think you can demonstrate physically how your conjecture would work, please do so. All the evidence and physics in the world is against it, so you have your work cut out for you.
Just a note about Crowley’s view of CAGW. He sounds like a reasonable scientist who lets the facts lead him, not the other way around.
http://www.geos.ed.ac.uk/homes/tcrowley/response_to_lovelock.pdf
I have referred to this paper many times in my comments here. It is a review of written documentation of weather pattern shifts that occurred following the 1257-8 explosion.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CEAQFjAE&url=http%3A%2F%2Fjrscience.wcp.muohio.edu%2Fclimatepdfs02%2Fclimimpts1258volcaclimchg00.pdf&ei=bbfnU6XFGqTCigLj7oCwDg&usg=AFQjCNHLGf3IVaNVvZvVXYt9GrJOwgSFjQ&bvm=bv.72676100,d.cGE
Pamela Gray says:
August 10, 2014 at 11:17 am
You are aware, are you not, that Lovelock has admitted he was wrong?
Science has decent actual thermometer data for the global effects of VEI 6 and 7 eruptions to some extent for Tambora, but especially for Krakatoa (1883), Tarawera (1886), Santa Maria (1902), Novarupta (1912) and Pinatubo (1991). It’s obvious those occurring during the Modern Warm Period didn’t produce a Little Ice Age, or cause the real one to continue. The decades since the 1880s have been an unusually volcanic interval, yet we’re in a warming period, not a cooling one. All before Pinatubo also occurred under lower CO2 levels.
So your conjecture was born falsified.
Pamela Gray says: August 10, 2014 at 10:01 am
Sturgis, Vuk, Page, and……
Miss Gray
Here is what Vuk has to say:
For your hypothesis to be credible you need some data to prove the point.
I’ve looked at your link, it shows strong volcanic activity from 1805 to 1820.
I suggest you go to the CET website
http://www.metoffice.gov.uk/hadobs/hadcet/cetml1659on.dat
and plot the CET’s 10 year (cantered moving) average from 1750 to 1850
you may fond :
– From 1750 to 1805 the CET averaged 9.1C
– during eruptions from 1805 -1820, temperature dropped by an average of 0.2 C
– After eruptions stopped the temperature rose, averaging 9.3C between 1820 to 1835, then new eruptions started. Point here to consider is that immediately after one of the strongest serious of volcanic eruptions in the temperatures recorded history, temperature rose and not only returning to its 50 year per-eruption average but significantly exceeding it
You draw your own conclusion.
I base all my conclusion on the observation data available, and wherever possible provide graphic illustration based on such. Many scientists do not like and dismiss what is in the data, but again not everyone agrees with the well-known Feynman quote on the matter.
Pamela Gray says:
August 10, 2014 at 11:26 am
Why is the distinction between weather and climate so hard for you to grasp? No one denies that big volcanic eruptions can affect weather. Quite the opposite, as I’ve repeatedly tried to point out to you. But they don’t alter fundamental underlying climatic patterns, which are always promptly returned to after the weather disturbances peter out in a few years, or in the case of supervolcano Toba, possibly several years.
There is zero evidence that the MWP, c. 800 to 1400, and the LIA, c. 1400 to 1850, were caused by volcanic activity or lack thereof, and all the evidence in the world against that baseless assertion. Big volcanoes went off during both the warm and cold period, and their effects on weather were limited in time. Climatic effects must be evident on the scale of 30 years or more.
http://onlinelibrary.wiley.com/doi/10.1029/2010JA016220/abstract
This is the direction the data is leading us.
Volcanic activity acts in concert with solar activity in that it tends to increase during prolonged solar minimum periods. In addition when volcanic eruptions do occur they will spike the temp. down for a short duration of time even when the overall temperature trend may be down.
Temp. trend will always zig zag and volcanic activity accentuates this.
There has been enough interest in the 1257 event, as well as other volcanic events, and their potential to extend climatic effects beyond the immediate obvious ones, that models are being used to explore this very interesting (to me anyway) area of research.
http://nldr.library.ucar.edu/repository/assets/osgc/OSGC-000-000-002-060.pdf
Sturgis, you do realize that after providing you with peer reviewed research in link after link after link directly supporting several of my underlying premises that your argument against me having done so is growing thin.
Pamela Gray says:
August 10, 2014 at 11:56 am
If you like tree rings, you’ll love models.
The actual data say that you, Mann and all the other anti-scientific CAGW shills trying so desperately to get rid of the MWP are dead wrong.
You haven’t got an evidenciary leg upon which to stand. If you can’t offer a quantified explanation for the climatic change you imagine (which objectively did not happen), then at least adduce some evidence that it even occurred. You can’t. ENSO patterns didn’t change 1257-86, the minimal time needed to show a climatic rather than weather effect from the 1257 eruption which has so enthralled you.
My climate forecast is based on solar parameters that if met will cause the climate to go in an x direction. I give hard numbers and it is easily falsified or verified.
My web-site has the parameters and the climate reaction.
To summarize quickly the atmospheric response will continue to be meridional and the global temp. trend will be down but not in a straight line but in jig saw fashion.
The data any way it is sliced shows solar activity changed quite a bit during year 2005 into a much quitter state. The questions are how long does it last and does it get as deep or deeper then it did during the 2008-2010 period.
Pamela Gray says:
August 10, 2014 at 11:58 am
You have not presented a single link showing a climatic effect from the 1257 eruption or any other. There are no actual data showing the LIA began in 1250, only assertions by the Team trying to “get rid of the MWP”. There are no data showing a climatic effect from any volcanic eruption, even Toba, the biggest of the past 27,800,000 years. Specifically, there is no change in ENSO patterns which your conjecture requires, nor can you offer a quantitative physical explanation for how your belief would actually work.
You have nothing, nada, zero, zip, zilch. If you think you do, then post the link and cite the specific parts of it which you imagine supports your baseless assertion. The expert whose data you use admits there is no climatic effect. You’re free to believe whatever you want, but science requires evidence, of which you have none. All the actual evidence in the world is against you.
Sturgis once again, simple volcanic activity is not my point of interest. I am only concerned with stratospheric veiling that has the potential to cause weather regime shifts. And contrary to your view of the difference between weather and climate, my position is stronger than yours in term of what I call short and long term weather pattern variations and regime shifts, and the stable outer boundaries of geophysical climate under our current land mass distribution over the past several millennial years, and natural intrinsic weather pattern variations regime shifts.
And I have considered the Milankovitch theory which holds a more broad position in my mind in terms of its affect on our climate (I take the theory on its general basis, but with lots of wriggle room as does the paper I link to below). However, for the purpose of the present discussion, I discard it as an issue during the Little Ice Age regardless of when you or I consider its starting point of the slide into a colder (though noisily so) weather pattern regime shift.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CCoQFjAC&url=https%3A%2F%2Ffaculty.unlv.edu%2Flachniet%2Fpublications_files%2F00%2520-%2520Devils%2520Hole%2520-%2520Literature%2520Compilation.pdf&ei=M8PnU-3mIKisjAKxrIC4DA&usg=AFQjCNEKu9KRugEniJkm6eClB29d5I4rHA&bvm=bv.72676100,d.cGE
The solar lull 2008-2010 goes a long way in confirming solar variability is greater then what is presently thought. It also gives credence that solar conditions during the Maunder were much weaker then what this recent solar lull of very short duration displayed in contrast to the Maunder Minimum ‘s duration of some 50 plus years.
We will see going forward. I think past solar data shows solar variability is there and much greater then this .1% phony TSI variation between typical solar sunspot cycles.
Pamela Gray says:
August 10, 2014 at 12:18 pm
Who besides you imagines that events lasting a few years constitute climatic phenomena? In real climatology, climate is the average of weather over 30 years or more.
What convinces you that the LIA needs a special explanation for what is a normal fluctuation in centennial to millennial scale climate? That is, what negates the Null Hypothesis that the LIA has the same underlying causes as prior cold periods following warm periods in the Holocene, the Wisconsin glaciation, the Eemian interglacial, the prior glaciation and all other such cycles going back at the very least to the Miocene?
On what basis do you rule out Milankovitch cycles as causes of centennial and millennial scale climatic fluctuations, when it’s well established that they control cycles of ten to hundreds of thousands of years?
How do you suppose a single eruption or even two 23 years apart can cause centennial to millennial scale changes in climate. Show the physics behind this unwarranted assumption. But first show that such a change actually occurred. It manifestly did not in the ENSO, for which good 13th century proxy data exist. Nor in any other valid climate data set.
In fact, you have less than nothing, since all the evidence in the world is against you.
For instance, this study of thousands of years of ENSO history based upon mid-Pacific corals specifically weighed potential volcanic and solar influences, finding a possible solar effect during the early to mid-MWP, AD 900-1200. The MWP and LIA (c. 1500 to 1800, but with data lacking on both sides of that central period) as well established by other data sets show up clearly:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CD0QFjAE&url=http%3A%2F%2Fshadow.eas.gatech.edu%2F~kcobb%2Fcobb_iowa.pdf&ei=S8jnU46OAuOjigLCm4D4BA&usg=AFQjCNHhP0xQB7gDo8YjNRwp_3JSWeFF6g&sig2=iPpWMphw3khxOm_nLanELA&bvm=bv.72676100,d.cGE
Sturgis, the Walker Cell low/high pressure system drives/maintains/interrupts El Nino/La Nina events. The physical mechanism of air movement between low and high pressure systems is well understood and especially in the Pacific equatorial band. Large tropical volcanic events can and do disrupt this Walker Cell circulation. I am sure you understand this. So it begs the question why you seem unable to declare that this is well-known in the literature.