What modulates our Sun? The majority of science work on the principle that the Sun is self modulating and each solar cycle is a product of a random number generator. There are others that suspect the Sun is modulated by the planets with a special emphasis on Uranus & Neptune. Thanks to Carl Smith who has recently left us we have new knowledge that significantly adds to Jose, Landscheidt & Charvàtovà's work.

Geoff Sharp

A Guide to Understanding the Solar Powerwave.

Fig.1. Click on the graphs for a full size view. Only one strong Disruptive Force this cycle ensuring a weak Dalton type event.

Understanding the Powerwave action that controls solar output in respect to Angular Momentum Theory (AMT) is a  fundamental requirement that perhaps very few have a basic insight. This article will attempt to explain the theory in segments which will hopefully spread some insight into this fascinating real world observation.

AMT begins with the orbital path of the Sun. The Sun does not remain stationary in the centre of the solar system, but instead orbits a point or gravitational centre of the solar system (SSB). The gravity of the outer 4 planets determines the daily position of the Sun which follows a kaleidoscope pattern orbit around the SSB. The orbit shape is basically an inner loop followed by and outer loop and is primarily controlled by Jupiter and Saturn.

Fig. 2 The green/purple line denotes the centre of the Sun on its path around the SSB (red crosshairs)

At its greatest point the Sun can have its centre 1.6 million kilometers from the SSB and also experiences a 100% velocity change compared to the inner loop that generally returns to the SSB, the two loops each follow a rough 10 year timeline which DO NOT line up with solar cycles. Solar Angular Momentum is calculated from these movements and can be seen in Carl's famous graph.

Fig. 3. Carl's Graph derived from JPL data.

AMT has two cornerstone forces.

1. The Modulating Force.

2. The Disruptive Force

Fig.1 shows a pink powerwave that modulates the height of solar cycles and is the Modulating Force. This wave follows the general trend of solar activity which correlates with the solar Angular Momentum (AM) wave, the top of the wave is always at the conjunction of Uranus & Neptune. This wave has been described many times in science and is sometimes called the Gleissberg cycle, the AM wave is powered by Jupiter and Saturn but is modulated by Uranus and Neptune as they return to conjunction every 172 years (this function also recently observed by Scafetta). While observing the modulating wave it is important to understand the integration of the Disruptive Force which can easily knock out the high solar cycles at the peak of the wave.

The Disruptive Force is the only variable in solar output (other than the smaller Modulating Force) and ultimately is what controls the shape of the Holocene solar record. The Disruptive Force comes from two particular planetary positions that occurs in groups near the top of the AM modulating wave. The Main Disrupting Force is experienced when the outer 4 planets are in the position shown in Fig 4.

Fig. 4. Type "A" at 30 deg. being amongst the strongest perturbations and grand minima of the Holocene.

Uranus and Neptune when near conjunction alter the normal pattern of Angular Momentum because of their combined gravity as seen at the green arrows on Fig.3. At the same time the normal path of the Sun is altered as seen by the purple curve on Fig.2. Charvàtovà and others have noticed that solar grand minima occur during times of the altered path of the Sun but now we can understand how to quantify the solar downturn that occurs during the altered path. The altered path of solar cycle 20 is not that different to the current cycle but the results should be very different. There is also another altered path (Type "B") that is generally weaker but just as important and not observed by Charvàtovà. The Disruptive Force or Angular Momentum Perturbations (AMP) occur in groups separated by roughly 40 years either side of the height of the Uranus/Neptune modulating wave. Most common is three groups per 172 year cycle (avg) but can be as few as two and as many as five. By understanding the strength of each disrupting or AMP event we can determine the amount of solar downturn for the era, this is done by observing the perturbation shape on Fig. 3 at the green arrows and by also observing the 4 outer planet angles in relation to each other as seen in Fig.4. and Fig. 5.

Some may ask why does the Disruptive Force have so many different strengths and occurrences during the height of each 172 year wave. Jose back in 1965 made the mistake of declaring the outer 4 planets return to the same position every 178.8 years. This simply does not happen and can easily be verified by using any online solar system viewer and going back in steps of 179 years. The orbital mechanics of the outer 4 planets move very slowly over thousands of years whereby the positions evolve and never return to the same position (but come close every 4627 years or 27 x 172 yr cycles). This evolution of the outer 4 planet positions is what shapes the Holocene solar record seen in Fig 5.

Fig. 5

When looking at solar output over greater timeframes another powerwave is observed. This wave is the Holocene record itself which is determined by the strength of the Disruptive Force over the 11,500 year record. Strong alignments of the outer 4 planets coincide with deep grand minima, while weaker alignments agree with the Medieval, Roman and Minoan Warm Periods. This is also observed in Fig. 6 when comparing the quantified AMP events with the Holocene isotope record.

Fig. 6 Figures 5 & 6 plotted from original Solanki (INTCAL98) carbon 14 data

AMT does not include what determines the length of the solar cycle and there are times when the Disruptive Force is weakened because of timing. If the AMP event happens near cycle max the full effect is not realized. It is thought that the Disruptive Force causes a "phase catastrophe" in the Hale cycle whereby one solar pole does not reverse polarity which then takes another full cycle before recovering. If the timing is wrong this will not occur, 1830 is a good example in the modern record.

Understanding the mechanics of both forces makes it relatively easy to understand the rest of Angular Momentum Theory and the power of the Angular Momentum wave, it should also be obvious that because of the inconsistancies in the wave, a firm recurring pattern of grand minima is not possible. There is now a peer reviewed paper by Wolff and Patrone that provides a mechanism for planetary control of solar output. If there are any questions on quantifying the Disruptive Force or any other area I am most happy to respond in comments.

A full version containing more information is available in my paper HERE.

Geoff Sharp.


Here is some interesting

Here is some interesting research from tallbloke that also shows the same powerwave. Notice how the Dalton Minimum breaks the wave with the Disruptive Force acting on its own. If I am not mistaken the blue line is the amount of planet mass above and below the solar equator (both records highly smoothed). It would be interesting to see if this pattern is repeatable over 1000's of years? (or would the natural orbital precessions move the peak of the wave over time?).... but I would be surprised if this is more than a shorterm artifact of the solar system dynamics that follows the natural AM cycle, which is the Modulating Force. The Disruptive Force is nowhere to be seen with this data set.

Another graph from

Another graph from tallbloke's blog by Tim Channon showing the upslope of the powerwave. This time it is the temperature record which will follow the Modulating Force and Disrupting Force powerwave. But this temperature drop will not be as long and sustained as experienced during the Maunder Minimum or even the Dalton Minimum. Our very small contribution to global warming mainly caused by deforestation and the Urban Heat Island effect will also buffer some of the expected overall drop in temperature. The Disruptive Force will be weak for the next thousand years which might be known as the Great Warming Plateau, our challenge is to accept this is a natural stage of the Holocene cycle that will end soon..

The disruption during the

The disruption during the Dalton Minimum I assume is the orange line or Lean TSI curve. There is some doubt on the accuracy of this reconstruction but even so the sunspot cycle shows a similar trend. The solar angular momentum graph indeed shows solar disruption during this time that closely resembles the current situation. If the theory is correct we should witness a solar downturn during SC24/25 not as long as the Dalton Minimum.

It will be interesting to see

It will be interesting to see what happens to the powerwave over the next couple of decades. I have a view that the closer the planets are to the plane of the sun's equator during the planetary alignment the larger will be the disruption. This is because the gravitational forces, which ultimately produce the disruption, are strongest when there is an alignment in 3 dimensions. Since the total planetary mass is closer to the sun's equator than at the onset of the Dalton minimum there might be a bigger disruption than expected.

This would be consistent with one of Ian Wilson's papers which showed that the greatest gravitational effect on Earth from the sun, moon (and Venus) is when the moon is in line of nodes that is on the same plane as the sun and Earth. ( Note that of all the planets Earth's orbital plane is closest to the sun's equator.)

REPLY: Hi Brent,  the powerwave is based on solar AM, the vertical alignment will probably have no effect. Gravity is not an issue when determining solar AM in the strictest sense as the Z axis (vertical) is taken into consideration when calculating solar AM. If the powerwave was a function of tidal forces then your comment would be more applicable, I see Leif Svalgaard is now on the Maunder Minimum band wagon, which I dont think will happen.

Brent Walker

Geoff, am an avid follower of

Geoff, am an avid follower of your site and agree that there seem to be a relationship between planet possition and the solar activity level.  I have one question related to power wave etc vs sun position vs center solar system.  Your figure 2 which shows sun looping through the center of the solar system shows that in 2030 the sun loops back to near the center even more close to center than in 2013 yet this has no relationship to the angular momentum chart.  What seem to be undiscussed is what is hapening when the sun itself undergoes thes sweeps around the center.  With the core solid and the huge radiative and convective gas/plasma layers above the core it would seem the the core would have to phyically interact with these other layers causing disturbed flows which would last a relatively long time given the changing direction and rotational spin of these unusual loop of solar motion take years.  It might be that these loops to the center (caused by the planet positions) cause the core of the sun to react differently causing disturbed flows which could interact with the magnetics on the sun.   If that were true, then in some cases the path of the loops by the sun into the center of the solar system would cause a weakening of activity because the disturbance would slow solar rotation (flows) or increase activity because they added to flows...bill

REPLY: Hi Bill, thanks for your question. Evidence suggests that the CLOSER the path of the Sun is to the SSB the higher the solar output (SC19), this can only happen when N/U are together. But there are conditions where this can be reversed. If the cycle before has experienced a strongly disordered orbit and a corresponding breakdown of the solar cycle which is thought to disrupt the Hale cycle, it doesn't matter how close the orbit comes to the SSB as the solar poles are negated. We should see evidence of this phenomenon after cycle max of SC24. The important aspect is to observe how far the disordered orbit travels away from the SSB which mirrors the amount of perturbation on the AM graph.


OK but the thing that grabs

OK but the thing that grabs me is the loop the sun takes through the SSC around 2030 is even tighter (more sharp) than it is during SS24.  It would seem that this would cause an impact in solar activity such that it could drive the sun into even quieter activity than is predicted by SC5 unless there was a similar second loop around the SSC in the 1820s that also didn't have an effect. I believe this is possible since the path the sun takes inward toward the SSC around 2030 is from a similar direction vs the SSC as in SC24.  I believe there are natural reasons why the sun has a variable nature and that the planet positions are involved.  I also believe that these solar loops into the SS center are involved. The answer could be a combination of effects which disturb the flows in the various layers on the sun which would be related  to why solar rotation rate varies from the solar equator to the poles.  bill


WUWT cowboy Willis Eschenbach

WUWT cowboy Willis Eschenbach has an interesting post re the Gleissberg cycle. The Gleissberg cycle is a supposed quasi 80 year solar cycle taken from a few hundred years of sunspot records. Eschenbach claims to have found a flaw in the Gleissberg methodology but he and Gleissberg fail to understand the mechanism in the background. I have attempted to educate Eschenbach but he refused to listen, but once understood it becomes clear why the 80 year cycle is not fixed in stone. My Powerwave article shows the 2 concepts required to understand the changing nature of the Gleissberg cycle that is now backed up by authors McCracken, Beer, Steinhilber etc in their latest paper. Judging by the comments on this topic on WUWT there is no understanding of these principles. If there are any questions I will be happy to answer on the Powerwave article.

Eschenbach backing up with another article on the Gleissberg cycle...he just doesnt get it. There is no exact 80-88 year cycle, only a most common gap of 80-88 years between low points in solar activity. The normal non grand minimum type  of low cycles at U/N opposition and the varying grand minima at the top of the U/N wave when near together. Grand minima occurring in different spots on the top of the wave.

GEOFF, my discussion on

GEOFF, my discussion on talkblokes talkshop, follows below. Don't get me wrong I think solar system dynamics play a role when it comes to variability of the sun, but is it the only item that effects solar variability? That is the question in my opinion.


Also I think there are to many potential solar cycles trying to be proven/shown  which are taking away from this theory rather then strengthening it.


What I say on talkblokes talkshop. Below


According to solar cycle strength the period from 1890-1910 should have been the least active period of solar activity since the Maunder Minimum, unless the 1450 year solar cycle and the 116 year solar cycle off set the shorter cycles minimum levels around that time frame.

The chart (which Weather Cycles sent) shows clearly the 194 year solar cycle and the 62.5 year solar cycle both to be PEAKING at the time of the Dalton Solar Minimum, while around 1900 these same cycles were at or near minimum levels, yet the Dalton Solar Minimum was less active then the period 1890-1910.


I conclude that in addition to solar cycles ,solar internal dynamics probably play a role in solar variability. Evidence of this is the sudden drop in solar activity during the year 2005. The sun suddenly shifted gears that year. It was not solar cycles per say that caused this in my opinion, although they may have contributed. In addition many other sun like stars exhibit Maunder Minimum Periods.

The longer solar cycles in my opinion being to slow to change over a period of LESS then 100 years to contribute in such a way which would result in the Dalton Solar Minimum being less active then the solar period 1890-1910.

NOTE: Why if longer solar cycles (presently in an upswing) were the cause of the solar quiet period from 1890-1910 to be LESS severe then the Dalton Solar Minimum are these same longer solar cycles (which are still on an upswing) NOT going to have the same effects going forward?

Apparently the thinking is they are NOT going to have the same effects since many solar predictions are for Dalton Solar conditions or even quieter solar conditions to return over the next 20 to 30 years.

This solar cycle theory just does not hold up to the degree some are trying to convey in my opinion. Something else is affecting the sun besides just solar system dynamics..


I don’t necessarily care what brings the solar parameters down to the levels I want. It could be solar cycles caused by solar system dynamics, or dynamic changes on the sun, or both..

Maybe lunar declination plays a role.

All that aside my prediction is based on x solar parameters resulting in an x climate result through primary and secondary solar effects.


Geoff , the following are questions I had asked on talkblokes talkshop under the Hale Cycle article that came out a week or so ago. Maybe you can shed some light . Thanks.

Another question (and I am not trying to be hard on you Weather Cycles ) show me how the 18.6 yr declination cycle embedded into the global temp. pattern and in synch +/- 2 yr with the schwabe/AMO global temp, cycle can explain the abrupt temp. drop at the start of the Younger Dryas and the abrupt temp. rise at the end of this period and why during the 1300 years it lasted this combination of events you allude to had no dramatic effects on bringing the earth out of this period of cold?

Why were the climatic swings so much greater in the period 20000 years ago to 10000 years ago then in contrast to the past 10000 years if what you say governs the whole climatic system is true?



REPLY: A lot of wrong assumptions perhaps.

There is enough variability in the solar orbit to explain all variations in solar output. Remember there are two forces, the modulation of AM and the disruption caused by the AMP event. Nothing else is required.

There are no distinct repeating cycles in solar activity in relation to grand minima. This is the key issue that Willis and the majority of commenters on the Talkshop are missing. McCracken et al are aware of this so the message is not totally lost. Adhering to strict cycles will always bring you undone, the solar system does not follow these rules.

The Sun entered the disordered orbit in 2005.

Around 1900 is just low AM caused by U/N being opposed, this is not a grand minimum and is the bottom of the Gleissberg quasi cycle....quasi as in being very variable.

The moon is not capable of affecting Solar output. The orbit shape changes to insolation override solar grand minima etc, the Younger Dryas is most likely a comet impact or Earth driven climate event.

Question given what you are

Question given what you are projecting for future solar activity do you think my solar parameters below will be reached or at least approached for the balance of time over the next 20 years? If so I  expect significant climate impacts.


Solar Flux sub 90

Ap index sub 5.0


Solar Wind 350km/sec or lower

Cosmic ray count 6500 counts per minute or highr


Euv light 100 units or less


Many % drop in various UV light of different wavelengths


IMF around 4.0 nt


I am also of the opinion that the earth's magnetic field strength, the beginning state of the climate and Milankovitch cycles play a big role in the climate picture and radomness and chaotic happenings are also present in the climate system which combined with solar variability and the other three  items I have mentioned can give infinite climate outcomes.


The climate system being both random and ordered in a sense.


REPLY: The solar values quoted are solar minimum values. The majority of SC24/25 will be substantially higher than these minimum values. What is important is the cycle max values that are around half of a normal cycle, especially when looking at EUV. Add the effects of the PDO and most is covered ...outside of ice ages of course.

These four factors either

These four factors either combined or in some combination are responsible for all the climate changes on earth. If one agrees with this then one will also have to agree that global climate change is synchronous.
1. The initial state of the global climate.
a. how close or far away is the global climate to glacial conditions if in inter- glacial, or how close is the earth to inter- glacial conditions if in a glacial condition.
b. climate was closer to the threshold level between glacial and inter- glacial 20,000 -10,000 years ago. This is why I think the climate was more unstable then. Example solar variability and all items would be able to pull the climate EASIER  from one regime to another when the state of the climate was closer to the inter glacial/glacial dividing line, or threshold.
2. Solar variability and the associated primary and secondary effects. Lag times, degree of magnitude change and duration of those changes must be taken into account. I have come up with criteria . I will pass it along, why not in my next email.
a. solar irradiance changes- linked to  ocean heat content.
b. cosmic ray changes- linked to clouds.
c. volcanic activity- correlated to stratospheric warming changing which will impact the atmospheric circulation.
d. UV light changes -correlated to  ozone which then can be linked to atmospheric circulation changes.
e. atmospheric changes - linked to  ocean current changes including ENSO, and thermohaline circulation.
f. atmospheric changes -linked also to albedo changes due to snow cover, cloud cover , and precipitation changes.
g. thickness of thermosphere - which is linked to other levels of the atmosphere.
3. Strength of the magnetic field of the earth. This can enhance or moderate changes associated with solar variability.
a. weaker magnetic field can enhance cosmic rays and also cause them to be concentrated in lower latitudes where there is more moisture to work with to be more effective in cloud formation if magnetic poles wander south due to magnetic excursions in a weakening magnetic field overall.
4. Milankovitch Cycles. Where the earth is at in relation to these cycles as far as how elliptic or not the orbit is, the tilt of the axis and precession.
a. less elliptic, less tilt, earth furthest from sun during N.H. summer — favor cooling.
I feel what I have outlined for the most part is not being taken as a serious possible solution as to why the climate changes. Rather climate change is often trying to be tied with terrestrial changes and worse yet only ONE ITEM , such as CO2 or ENSO which is absurdity.
Over time not one of these one item explanations stand up, they can not explain all of the various climatic changes to all the different degrees of magnitude and duration of time each one different from the previous one. Each one UNIQUE.
Examples would be the sudden start/end of the Oldest, Older and Younger Dryas  dramatic climate shifts, the 8200 year ago cold period, and even the sudden start of the Little Ice Age following the  Medieval Warm Period.

There are no distinct

There are no distinct repeating cycles in solar activity in relation to grand minima. This is the key issue that Willis and the majority of commenters on the Talkshop are missingThere are no distinct repeating cycles in solar activity in relation to grand minima. This is the key issue that Willis and the majority of commenters on the Talkshop are missing.



Geoff I see what you are saying. That is what has thrown me off . The disruption that has been present post 2005, in contrast to be absent around 1900. That explains much.  Thanks


REPLY: That's it, two distinct actions with the grand minimum option occurring at differnet points at the top of the wave...Now if we can just educate the likes of Willis how quasi cycles work.

Geoff , your theory is the

Geoff , your theory is the best explanation out there and makes so much sense in sharp contrast to the characters present on WUWT which are agenda driven.


A question, remember the recent post I gave on avg. solar parameters? Do you have any thoughts  as to what those various solar parameters were like during the Dalton and Maunder Minimum solar periods?




I think sub 5 for the ap index is going to be the rule for this current solar prolonged minimum given the ap index  has been close to this value during the entire  maximum of solar cycle 24. I also think this value  has climate implications along with all the other values I have mentioned.




My thinking has been in contrast to yours in  that I think it is more important what minimum solar values are attained  in the various solar paramenters and how long they last. Reason being,  these minimum values are far more likely to bring about climatic thresholds if deep enough /persistent enough since they are not visted all that often during normal periods of solar activity.


To put it another way I think the more extreme the solar parameters become the more likelyhood of a greater solar climatic impact. The sub values reached during the maximum part of the solar cycle are important as you spoint out,  and I think the reason why is because they contrbute to the accumulaton factor of sub solar activity in general which to me sets the stage for very low minimum solar values once they return to have that much more of an impact upon the climate, then would be the case otherwise.


Also the decline in the earth's magnetic field post Maunder Minimum, will enhance any solar effects upon the climate in my opinion. Do you agree with that ? Thanks.



I think it is important to

I think it is important to separate solar activity from climate, both are interrelated in my opinion but maybe to a lesser degree, internal ocean oscillations perhaps playing a bigger role. I do not rule out a solar system influence on the ocean cycles.

Thresholds are not important in my opinion as there is no evidence of a tipping point relating to climate from solar thresholds. The only evidence I see is the possible relationship of reduced EUV output which looks to affect ozone at different levels of the atmosphere and the possible related jet stream and pressure pattern changes. The thermosphere shrinks as soon as the EUV drops and does not wait for a threshold, but the solar max EUV values of around half of earlier cycles is what continues to maintain the ozone changes and related atmospheric changes. These changes over the global temperature are likely to be small over the next two cycles as the ocean heat position now is very different to the LIA, but we will see very different weather patterns than witnessed over the last 40 years. We are in a different paradigm now with only very weak grand minima expected for at least a thousand years, the LIA period is a rare event across the Holocene.

What drives the Sun is a more interesting topic in my opinion, and I marvel at all those getting on the Maunder band wagon. To date I have not seen one shred of evidence suggesting we are heading into a grand minimum as low as the Maunder Minimum.

  I dont understand why most

  I dont understand why most people think the oceans were 'different' temperature wise coming into the LIA.  The medival warm period was warmer and longer than the current warm period soooo... the oceans should have been just as warm then as now and still the climate 'took a dive' into the I missing something?


The oceans play a big role no

The oceans play a big role no doubt about it, but I am a believer right or wrong that  not only does the solar system influence the oceans but also the atmospheric circulation patterns.


I think oceanic patterns and atmospheric patterns are interwined in a very complex irregular manner  which should prove interesting as the jet stream becomes more meridional in response to prolonged minimum solar actiivty.


One reason why I believe in thresholds is due to the evidence of many past  abrupt climatic changes from ice cores taking place over just decades.  This suggest some sort of thresholds being reached .


I take it you don't buy into the cosmic ray theory  which is low solar conditions give rise to more cosmic rays which create more low cloud formation /colder temp. or the theory that volcanic eruptions of  an explosive index of 4 or greater seem to take place much more frequently around solar minimum periods rather then solar maximum periods.



I am a big believer in the ozone changes in response to solar changes equates to atmospheric pattern changes.


One last note is I think  solar wavelegths of light in the visible light wave length range  and just into the UV range of wavelengths  have much to do with ocean heat content. When these values decrease because they penetrate the surface ocean waters to great depths the ocean heat content should evenually decrease over time.


Thanks for all the gret info. it will be interesting going forward.

But don't you think it is

But don't you think it is possible for an example, that if the thermosphere shrinks to some x value that a threshold of some sort could be reached?


What I am trying to say using that as an example is I think the climate will function in relatively stable fashion but if x values are attained in an item or items that influence the  climate that this x value could cause the climate through positive feedbacks associated with that x value of that item or items   to shift into another regime and over a rather quick period of time, once those deviations in those x values of those  items that control the climate are reached.


It could be from an increase in more  low clouds, increased volcanic activity, increase in snow cover, sea ice, a more meridional atm. circulation, or any number of things. i just mentioned a few  to make my point.

Ice ages are a different

Ice ages are a different matter that ARE subject to a threshold, Earth's orbit shape, inclination and precession all contribute to a point where snow cover exists at 65N during the summer which then has ongoing albedo impacts. But the last 5 or so winters have shown a very clear change in the jet stream and pressure patterns that have persisted during the lowest EUV values at SC23/24 minimum and still exist today at solar max, I think its not a threshold reached at minimum but more a prolonged period of not reaching a higher value that is causing the change...perhaps a threshold in reverse?

The Svensmark theory is still out to lunch perhaps....the cloud data is still not helping.

  I dont understand why most people think the oceans were 'different' temperature wise coming into the LIA.  The medival warm period was warmer and longer than the current warm period soooo... the oceans should have been just as warm then as now and still the climate 'took a dive' into the I missing something?

The oceans during the MWP were probably warmer than today but imagine if that period was followed by 1000 years of very weak grand minima like we are experiencing now instead of 600 years of the strongest grand minima experienced across the Holocene back to back. There is a huge difference in solar conditions when comparing both epochs?

That is a very good point you

That is a very good point you make mangin 3.


I  would venture to say that the current state of the climate is as close to glacial condtions today as it was at the start of the Little Ice Age. The Medieval Warm period being very long and at least as warm as today. Further what is amazing about the Little Ice Age is it came on in decades.  It took maybe 20 years to transition, it was very fast not slow.


This current period in our climate is very similar to how the climate was  just prior to the start of the Little Ice Age. I  am talking about the time period arouund 1300 AD.


My theory is when the climate shifts gears it does so very quickly, not slow and gradual which was the old school of thought until ice core data evidence showed otherwise.



Thank you Geoff, for all that

Thank you Geoff, for all that you do, I guess my question or point is I see many people dismissing the possibility of LIA conditions BECAUSE of the warm oceans but did not temperatures plummet quickly from MWP into the LIA even with the warm oceans and we really do not know what the sun was doing then...not until the mid 1600's or so. Is it possible the sun was as active in the 1200's as the 1900's and then sometime during the 1300's do as it is now? Did the MWP become the LIA within 2+ SC, or did it take longer?


The graph below might help.

The graph below might help. The purple line is the grand minimum strength of the planet alignments compared with both solar proxy records, the purple line is also the same as the future graph near the head of the article. The planet alignment strength line has purple boxes which are the summation of the multiple solar impacts that occur at the top of the AM wave when U/N are together. Notice how the MWP shows the weakest planetary alignments which then suddenly drop to strong alignments of four grand minima during the LIA. The first one around 1250 (Wolf Minimum) is a much stronger grand minimum than we are experiencing now and anytime in the next 1000 years. The solar contribution to climate would have been much stronger than now.

The planet alignment strength can be quantified via 3 methods.

1. The Saturn angle when opposite Jupiter, Uranus and Neptune.

2. The shape of the solar inner loop orbit (The start of the inner loop trying to escape the radius dimension of the Sun instead of returning to the SSB)

3. The AM perturbed curve on Carls graph ( large perturbations  on the downslope at about half way being the strongest)

This graph although it has margins of era as shown by the shading shows  how rapidly the temperature declined around or just after 1300ad which is the start of the Little Ice Age. Warm oceans prior to this period of time due to the Medieval Warm Period did not prevent this from happening apparently.

Also note another rapid plunge in temperature around 1400 ad.

REPLY: Temperature dropped less than a 1 Deg C in 700 years after 3 of the largest grand minima of the Holocene. What would we expect from a short less than Dalton like grand minimum today?

OK...Why if in 1705 a strong

OK...Why if in 1705 a strong type A disturbance is followed by almost .5 C degree temp rise in bout 10-15 years time !! Giant upswing ! But the first two in 1285 and 1450 or so are followed by sharp falls in temps...WHY ? I'm not to sure bout this temp graph Salvatore...Think temps colder during LIA...and warmer during Medival WP and cooler Modern WP...a bit warmist here!   Geoff , you have said SC24 weaker than SC5 and you are right...also you believe SC25 will be weaker than SC24...and I think you are right again...this then means you think the Landscheidt minimum will be stronger than the Dalton ... right...I think so.


The strong type A disturbance

The strong type A disturbance is around 1685, so perhaps a little late to affect SC1. We also need to be aware the SC1 values are not full of confidence. Solar is also only one factor.

I have not really made a prediction on SC25 other than it is likely to follow SC24, this is new ground and I am only going on past grand minima cycles where the intitial disruption looks to carry over to the next cycle if the disruption is strong enough to posiibly affect the poles etc. SC25 is guesswork really, no one has any real knowledge.

The Landscheidt Minimum is different to the Dalton, there is only one disruption that may affect 2 cycles. The Dalton had 2 disruptions with the second being partially wasted on SC7 because of timing, but none the less still forced one weaker type cycle. I expect SC26 to recover more than SC7.


Geoff, I am expecting an

Geoff, I am expecting an average  global temperature drop of around .5c if  the prolonged solar minimum continues, by the year 2020.  Note the drop will not be uniform across the globe with the largest drop in average global temperatures taking place over  N.H. land areas North of 45 degrees latitude, while the smallest temperature changes if any taking place in the tropics.

Note the graph I presented does have margins of era as shown by the gray areas .


An example would be around 1400 ad when  the temperature drop could have been -.1c to -.7c in a period of a few decades. I am saying could have been  because it is in the margin of era of this particular graph.


In addition this graph(as I alluded to ) is for the ENTIRE N.H.  meaning that most of the global average drop in temperature as shown by this graph was very likely  due to a temperature decline in land areas  north of 45 degrees latitude,  where it really has a big impact. I would venture to say that during the Little Ice Age the temp. drop over N.H. land areas North of 45 degrees latitude was perhaps on the order of -1c  to -1.2c  while in the tropics much less, maybe even zero.


In addition to the prolonged solar minimum the earth's magnetic field is much weaker then it was during the Maunder Minimum or the Dalton which I think plays a role in the climate.


One unknown going forward is volcanic actiivty in regards to how much ,how explosive and where does it take place.

Another  unknown are possible positive feedbacks which may or may not happen as a result of  a prolonged solar minimum period.  The climate system is random and chaotic meaning x changes in items  that affect the climate even if similar(solar for example) are not going to necessarily translate to the same climate outcome or outcomes.


Despite this I am confident enough to predict the trend for global average temperature will be down .




And no matter how much you

And no matter how much you squeeze the numbers you are sure we will not get a Landscheidt zero crossing in 2030? If it were a zero crossing would it effect SC25 or SC26 ? You are quite right to say solar is but one factor. Earths current weak magnetic field (and getting weaker), atmospheric aerosols, possibly cosmic rays, ect. ect. The next several years will be very interresting and I look forward to sharing it with you. Keep up the good work Geoff, and thank you for this site and all your hard dedicated work !


The Lanscheidt zero crossing

The Lanscheidt zero crossing has been shown to have nothing to do with grand minima as we saw in 1990, and even so the next time of zero  AM is 2170. The zero crossing method is now refined, but was responsible for providing a path towards our current knowledge.

Yes, but every time there is

Yes, but every time there is a zero crossing there is an Angular Momentum Perturbation within 20 years which 'could' contribute to an extended minima...could it not? The current/future period of angular momentum looks just like the mid 1600's...just missing the extra 'kick' in the 2030's.

REPLY: Yes that perturbation is happening now, and there is none to follow, so there is no chance of a slowdown after SC25, if the theory is correct. The AMP event at 1650 is actually stronger than the current event, the event happens earlier in the Jupiter/Saturn AM downslope and the inner loop orbit travels further away from the SSB.


I´ve been looking at the

I´ve been looking at the 10.7cm Flux and specifically the rotational flux over 27 days. As the absolute level of flux may vary quite a lot over time, the 27 days rotational flux might tell us something about changes in dynamic pressure of the solar wind.

So I´ve plotteed the 27 day flux changes for cycle peak years 2001, 2002 & 2012 & 2013. The interesting thing here is that the 27d flux does seem to follow a pattern from one year to the next. This implies that the solar output distribution is very much dependent on where (in which sector) in the solar system you are and that the solar wind is really not randomly distributed. Another question is of course why and what drives this distribution, but there might be a more deterministic process than one might think. Closest bet is the sun SSB position and the resulting tidal waves ripple on the sun surface.

Here´s the plots:


Geoff, commentary on this study which I find of great values would be appreciated.




REPLY: I am thinking there are too many conflicting solar contant type reports to put any faith in this particular report. Also to my eye any one metric that follows the temperature trend is probably bogus, a mixture of oceanic and solar drivers need to be combined.


I've been struggling to

I've been struggling to understand the solar powerwave, and almost got bored trying to figure out. Until your guide came to the rescue. I am getting into the grips now. Turns out it's mostly the Angular Momentum Theory which I had trouble understanding. Thank you for this guide.

Best regards,
Matias Luoma

After some 10 days lead in

After some 10 days lead in 2014 rotational flux change(27d) compared to last year, we are quite aligned with 2013 delta flux(27d). Forecast would then be some increased flux in october/november according to last years development. We´ll see what happens.

How it played out for

How it played out for 2014:

The 27d1y2m is 2 month 27 day change average from LAST year.
See how well it could forecast THIS year flux!

It is interesting that during

It is interesting that during this period of minimal solar activity there is a huge coronal hole in the south.

Brent Walker

~~Geoff,  we have disagreed

~~Geoff,  we have disagreed before on Milankovitch Cycles, maybe in part because I did not present my thoughts clearly. 


I hope with what I have to say below  it  is more clear,,  because history has shown eccentricity, obiquity and precession have all played more or less equal roles with no one factor dominating the other two factors  over the entire spectrum of time when deriving the beginning and endings of glaciation cycles when tied to Milankovitch Cycles.  For exampe for a time obliquity seem to correspond to the glaciation cycles to a greater degree then the other  two factors while in the last  800000 years eccentricity seems to correspond  to  glacial cycles to a greater degree.

I argue below  that in contrast to 10000 years ago when perhelion occurred  during the N.H. summer and the obliquity was greater , that  those two factors more then have off set the very slightly less eliptical orbit the earth has currently in contrast to 10000 years ago causing Milkanovitch Cycles on balance from 8000 BC(10000 years ago) to present to be the cause of the climate to drift into a very slow gradual cooling tend.


Data seems to support this. I admit the fact that becaue the orbit of the earth is quite circular this is not favorable for severe cooling but I am saying realtive to 10000 years ago Millankovitch Cycles are more favorable for cooling now in contrast to then, when they were very favaroble for warming.  Maybe a better way to say it  is,  Milankovitch Cycles are less favorable for warming today then they were 10000 years ago.





What fits the global temperature trend data the best since the Holocene Optimum- Present is what I suggest below.

My thoughts on what drives the climate conform to what the data shows(present/past), unlike AGW theory which totally ignores the data both present and past.

AGW theory wants the data to conform to what it suggest, not the other way around.

More data which shows since the Holocene Optimum from around 8000BC , through the present day Modern Warm Period( which ended in 1998) the temperature trend throughout this time in the Holocene, has been in a slow gradual down trend(despite an overall increase in CO2, my first chart ), punctuated with periods of warmth. Each successive warm period being a little less warm then the one proceeding it.

My reasoning for the data showing this gradual cooling trend during the Holocene ,is Milankovitch Cycles were highly favorable for warming 10000 years ago or 8000 BC, and have since been in a cooling cycle. Superimposed on this gradual cooling cycle has been solar variability which has worked sometimes in concert and sometimes in opposition to the overall gradual cooling trend , Milankovitch Cycles have been promoting.

Then again this is only data which AGW enthusiast ignore if it does not fit into their scheme of things. I am going to send just one more item of data and rest my case.


~~This article claims (which

~~This article claims (which I do not agree with) that low eccentricity is favorable for glaciation) This is not the only time I have come across this.  Am I reading this correctly?



Ice Ages and Milankovitch Cycles

Ice ages are long spans of time that marked by periods of time during which ice reaches far from the poles, interspersed by periods during which the ice retreats (but never quite goes away). The periods of time during which ice covers a good sized fraction of the Earth are called glacials; the periods during which ice retreats to only cover areas in the far north and far south are called interglacials. We are living in ice age conditions, right now. There's still ice on Antarctica and Greenland. We are also in an interglacial period within that larger ice age. The current ice age began about 33 million years ago while the current interglacial began about 11,700 years ago.

The Milankovitch cycles determine whether the Earth is in a glacial or interglacial period. Conditions are right for ice to form and spread when precession puts northern hemisphere summer near aphelion and winter near perihelion and when both obliquity and eccentricity are low. The Earth currently satisfies the first of those conditions, but obliquity and eccentricity are a bit too high. That makes our northern hemisphere summers are a bit too warm, our winters a bit too cold.

Many thanks go to Carl's brother Dave for providing the Domain, Server and Software.