Solar activity measured by isotope proxies revealed the end of 20th century was the highest activity in 1200 years
A 2010 paper (that I somehow missed) was recently highlighted by the blog The Hockey Schtick and I thought it worth mentioning here even if a bit past the publish date.
The work by Ilya G. Usoskin of the Sodankyla Geophysical Observatory at the University of Oulu, Finland was published in Living Reviews of Solar Physics. The paper examines records from two isotope proxies (Be10 and C14) and finds that solar activity at the end of the 20th century was at the highest levels of the past 1200 years. Excerpts follow along with a link to the full paper.
A History of Solar Activity over Millennia
Ilya G. Usoskin, Sodankyla Geophysical Observatory (Oulu unit), University of Oulu, Finland
Abstract:
Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview of the special indices used to quantify different aspects of variable solar activity, with special emphasis upon sunspot number.
Over long timescales, quantitative information about past solar activity can only be obtained using a method based upon indirect proxy, such as the cosmogenic isotopes 14C and 10Be in natural stratified archives (e.g., tree rings or ice cores). We give an historical overview of the development of the proxy-based method for past solar-activity reconstruction over millennia, as well as a description of the modern state. Special attention is paid to the verification and cross-calibration of reconstructions. It is argued that this method of cosmogenic isotopes makes a solid basis for studies of solar variability in the past on a long timescale (centuries to
millennia) during the Holocene.
A separate section is devoted to reconstructions of strong solar–energetic-particle (SEP) events in the past, that suggest that the present-day average SEP flux is broadly consistent with estimates on longer timescales, and that the occurrence of extra-strong events is unlikely. Finally, the main features of the long-term evolution of solar magnetic activity, including the statistics of grand minima and maxima occurrence, are summarized and their possible implications, especially for solar/stellar dynamo theory, are discussed.
…
4.4 Grand maxima of solar activity
4.4.1 The modern episode of active sun
We have been presently living in a period of very high sun activity with a level of activity that is unprecedentedly high for the last few centuries covered by direct solar observation. The sunspot number was growing rapidly between 1900 and 1940, with more than a doubling average group sunspot number, and has remained at that high level until recently (see Figure 1). Note that growth comes entirely from raising the cycle maximum amplitude, while sunspot activity always returns to a very low level around solar cycle minima. While the average group sunspot number for the period 1750 – 1900 was 35 ± 9 (39 ± 6, if the Dalton minimum in 1797 – 1828 is not counted), it stands high at the level of 75 ± 3 since 1950. Therefore the modern active sun episode, which started in the 1940s, can be regarded as the modern grand maximum of solar activity, as opposed to a grand minimum (Wilson, 1988b).
Is such high solar activity typical or is it something extraordinary? While it is broadly agreed that the present active sun episode is a special phenomenon, the question of how (a)typical such upward bumps are from “normal” activity is a topic of hot debate.
…
6 Conclusions
In this review the present knowledge of long-term solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method, is discussed.
Although the concept of solar activity is intuitively understandable as a deviation from the “quiet” sun concept, there is no clear definition for it, and different indices have been proposed to quantify different aspects of variable solar activity. One of the most common and practical indices is sunspot number, which forms the longest available series of direct scientific observations. While all other indices have a high correlation with sunspot numbers, dominated by the 11-year cycle, the relationship between them at other timescales (short and long-term trends) may vary to a great extent.
On longer timescales, quantitative information of past solar activity can only be obtained using the method based upon indirect proxy, i.e., quantitative parameters, which can be measured nowadays but represent the signatures, stored in natural archives, of the different effects of solar magnetic activity in the past. Such traceable signatures can be related to nuclear or chemical effects caused by cosmic rays in the Earth’s atmosphere, lunar rocks or meteorites. The most common proxy of solar activity is formed by data from the cosmogenic radionuclides, 10Be and 14C, produced by cosmic rays in the Earth’s atmosphere and stored in independently-dated stratified natural archives, such as tree rings or ice cores. Using a recently-developed physics-based model it is now possible to reconstruct the temporal behavior of solar activity in the past, over many millennia. The most robust results can be obtained for the Holocene epoch, which started more than 11,000 years ago, whose stable climate minimizes possible uncertainties in the reconstruction.
An indirect verification of long-term solar-activity reconstructions supports their veracity and confirms that variations of cosmogenic nuclides on the long-term scale (centuries to millennia) during the Holocene make a solid basis for studies of solar variability in the past. However, such reconstructions may still contain systematic uncertainties related to unknown changes in the geomagnetic field or climate of the past, especially in the early part of the Holocene.
Measurements of nitrates in polar ice allow the reconstruction of strong solar energetic particle (SEP) events in the past, over the five past centuries. Together with independent measurements of the concentration of different cosmogenic isotopes in lunar and meteoritic rocks, it leads to estimates of the SEP flux on different timescales. Directly space-borne-measured SEP flux for recent decades is broadly consistent with estimates on longer timescales – up to millions of years, and the occurrence of extra-strong events is unlikely.
In general, the following main features are observed in the long-term evolution of solar magnetic activity.
• Solar activity is dominated by the 11-year Schwabe cycle on an interannual timescale. Some additional longer characteristic times can be found, including the Gleissberg secular cycle, de Vries/Suess cycle, and a quasi-cycle of 2000 – 2400 years. However, all these longer cycles are intermittent and cannot be regarded as strict phase-locked periodicities.
• One of the main features of long-term solar activity is that it contains an essential chaotic/stochastic component, which leads to irregular variations and makes solar-activity predictions impossible for a scale exceeding one solar cycle.
• The sun spends about 70% of its time at moderate magnetic activity levels, about 15 – 20% of its time in a grand minimum and about 10 – 15% in a grand maximum. Modern solar activity corresponds to a grand maximum.
• Grand minima are a typical but rare phenomena in solar behavior. Their occurrence appears not periodically, but rather as the result of a chaotic process within clusters separated by 2000 – 2500 years. Grand minima tend to be of two distinct types: short (Maunder-like) and longer (Sp¨orer-like).
• The modern level of solar activity (after the 1940s) is very high, corresponding to a grand maximum. Grand maxima are also rare and irregularly occurring events, though the exact rate of their occurrence is still a subject of debates. These observational features of the long-term behavior of solar activity have important implications, especially for the development of theoretical solar-dynamo models and for solar-terrestrial studies.
Full paper here: A History of Solar Activity over Millennia (PDF)
==============================================================
However, according to the IPCC, none of this has nothing to do with 0.7C of global warming since the end of the Little Ice Age in 1850. And, even if you were to point it out to them for AR5, they have now clearly demonstrated they have no intention of paying any attention to any factual data that doesn’t fit the ‘CO2 and nothing else’ meme.
So is it your contention that a proxy estimation of sunspot number for the 20th century is better data than the actual sunspot number in the 20th century?
Because it doesn’t take much looking to find that the actual sunspot number peaked during Cycle Nineteen (1957-58), and has been declining irregularly ever since.
Leif Svalgaard says:
September 14, 2012 at 4:57 pm
Thanks Leif, that cleared-up one or two thoughts I had, you’re constructively thinking ahead, I like that! when this weak cycle comes to an end, every possible observation technique and experiment should be made available and implemented for this event.
Alec Rawls says:
September 14, 2012 at 9:23 am
Once in a while a comment doesn’t need a /sarc!
My stove is electric, so I can start out on high. 🙂
Ric Werme says:
September 15, 2012 at 9:12 am
Once in a while a comment doesn’t need a /sarc!
My stove is electric, so I can start out on high. 🙂
Grow up!
@Ric Werme
Leif Svalgaard says:
Jim G says:
September 14, 2012 at 1:42 pm
I see that, as per our last discussion, we go back to the adjustment of the older “raw” SSN’s using the “group” number.
Actually, not. We instead abadon the older group numbers. The calibration [‘adjustment’ as you call it – which is a bad terminology as we are calibratinf against a well-observed, objective, and well-understood independent measurement: the daily variation of the geomagnetic field [discovered in 1722].
This comment reveals the core of how post-modern politicised science works in the 21st century.
All data, of any kind in any field, is reassessed through a political filter. In politicised subjects such as climate, radiation carcinogenesis etc, an opinion is established (we have the Soviet Union to thank for establishing this mind-set and practice that is now universal and dominant in the European and American Scientific elites).
Then data is assessed by the filter of the established opinion and result. If it is found to be at variance, the first question is how to direct personal attacks against the scientist in question. In parallel with this, strategies and narratives are created to discredit the data.
This is why every single time data is found that identifies climate drivers other than the inquisition-orthodox CO2, then huge creative energy is expended – not to mention tax-payers money – to discredit (or give the appearence of discrediting) the heretical data.
It is imperative that climate skeptics and any who are concerned with scientific truth make as many copies as possible of the important data in every scientific field, especially climate, and keep these copies secure for the future, since the nights of public book-burning are not very far away.
I believe in carbon dioxide, maker of heaven and earth
and in greenhouse radiative warming, his only begotten son
who was conceived of the Holy Arrhenius, and born of Charles David Keeling
suffered under the axis of evil oil producing companies,
he descended to the madlands of skeptic hell.
on the third day he rose victorious therefrom
he ascended into heaven and sitteth at the right hand of Michael Mann
From thence he shall come to judge the heretic and the climate-deviant,
I believe in climate computer models,
the holy catholic team, the communion of software fudgers and decline-hiders,
the forgiveness of deceit, concealment, victimisation, murder, whitewashing, obscuring and deleting factual data in the name of CO2,
the resurrection of the dark ages,
and in uniform unchangeing climate and CO2 concentration in all times past,
280 ppm without end
Amen.
phlogiston says:
September 15, 2012 at 3:12 pm
This comment reveals the core of how post-modern politicised science works in the 21st century. …
Then data is assessed by the filter of the established opinion and result.
You could not be more wrong. The re-assessment of the solar activity record is done against the established opinion and overthrows old dogma and is not politicized in any way, quite the contrary.
phlogiston says:
September 15, 2012 at 3:12 pm
I believe in carbon dioxide, maker of heaven and earth, etc…
This admission of yours is perhaps telling…
@Leif
“The re-assessment of the solar activity record is done against the established opinion and overthrows old dogma and is not politicized in any way, quite the contrary.”
I am involved in a long drawn out re-establishment, I could say, of a certain field of science in which there are literally thousands of lab tests performed according to a certain protocol and which give a certain set of merics and claimed results. That is, the method of the analysis yields particular metrics. When I pointed out there were numerous manthematical errors in the calculations and errors of concept in the whole experiement, people first ignored then debated then accepted the issues were real, then drafted a new protocol. I thought, “Great. We will have a lab test that predicts field performance.”
The new protocol looks at pretty much the same data in pretty much the same way but makes a few less errors . When I challenged this result as pretty pointless because the tests still give nearly no useful information, I was informed that the new data has to be reported in a way that the old data can still be ‘converted’ to the new methods. This was the basis of their new science.
I pointed out that there was no point (at all) in translating old data that was based on or had as many as 33 errors so the ‘conversion’ from garbage to part-garbage is meaningless. Well the group pretty much ignored the observation. They have to have something to be able to make use of all that old data, apparently. And people are used to the old test method.
It seems to me you are in the same position. Just because it is being done openly there is still the obvious need to have all the old sunspot data ‘converted’ to some or other new system. Perhaps your result will be much better than the junk I have to deal with, but there is a lesson here: Make a no-holds-barred assessment of what constitutes meaningful metrics for solar activity and magnetohydrodynamics or whatever it is you need to quantify, and make no nod to the past. After working out how and what has to be done, then start to see if anything can be salvaged from old geezers looking through 4x telescopes at the sun centuries ago. If it is all but useless, tough. At some point the old junk has to go and if it turns out someone clever can make sense of it later by some as-yet-undetermined proxy, fine. But the risks posed by yet another set of partly effective methods are great. The politics is then reduced to managing the self-promoters or trouble makers.
Good luck with your quest.
Crispin in Waterloo says:
September 16, 2012 at 6:43 pm
The politics is then reduced to managing the self-promoters or trouble makers.
Good luck with your quest.
Luckily, everybody in the sunspot community is on-board for this re-assessment and we are making good progress. There are only a few trouble makers. The biggest problem is our ‘users’, the people that use the sunspot numbers and solar activity indices. They do not want any improvements if these upset their pet theories and correlations. They talk about ‘ironing boards’ and other assorted nonsense. Our solution to that is to for all sunspot-counters and index-producers to stand together, then after a while the recalcitrant users will begin to look silly [some are already in that boat – to wit some of the hand-wringers on this very blog]] and quietly be converted. We can also use the ‘name and shame’ mechanism which can be quite effective.
@Leif
I just read the PPT and it is still pretty bare without the discussion. I will try to keep up.
I have found that the idea of embrassing people into sensible positions is pretty infective and it has great dangers attached in that if you get one thing wrong and they get that one right, your will never live down the hue and cry that you are convering up or have another agenda. Look at all the pigeons that are coming home to CAGW crowd. They have been trying to use personal attacks as a consensus management tool for years. The science moves ahead faster than the evolution of what are ostensibly unity building maneuvers.
It is not all that different from the situation I face, actually. The raw data is mostly agreed (how to get it) but after than, there is chaos. If someone manages to notice something based on a strange interpretation of the data, fine – maybe it leads to something, maybe not. I am open minded. But 6 x 8 must still = 48, if you get my drift.
I appreciate the call for using less processed data and encouraging people to use the raw numbers. There is so much lost in the repreated conversions and smoothing. I use a data analysis method that requires all the raw data to be included on the page and all editing to be indicated with a colour change (We use large spreadsheets). I have no qualms about smoothing, but the raw data and the smoothed must both be available to anyone looking at it so they can try their own (prejudiced) hand if they wish. As is so clear in ‘climate science’, hiding how the result was obtained is a huge problem for people trying to think, instead of ‘accept’. Plus, they keep getting caught cheating.
I hope this warming castrophist nonsense will soon be over – it is more wasteful of resources than a major war. But I fear they will just lapse into the global cooling scare that was all the rage when I was young. Some thing never change I guess. Well, sunspots do…
Leif Svalgaard says:
September 16, 2012 at 7:16 pm
“……….We can also use the ‘name and shame’ mechanism which can be quite effective.”
==============
Sure you want to go here ?
Crispin in Waterloo says:
September 16, 2012 at 7:56 pm
if you get one thing wrong and they get that one right
We shall work so carefully that there will not be one thing wrong. This is not rocket science.
u.k.(us) says:
September 16, 2012 at 8:08 pm
“We can also use the ‘name and shame’ mechanism which can be quite effective.”
Sure you want to go here ?
Yes, although it is true that you catch more flies with honey than with vinegar, but when you have caught one, you squash it. As Hugh Hudson puts it [slide 10 of http://www.leif.org/research/SSN/Hudson.pdf ] :
This group needs to take charge of the perception of SSN:
– Consensus
– Public databases and ample publications
– Propaganda that discredits any research not using the consensus SSN
Severe [but necessary] gate keeping if you will.
Leif Svalgaard says:
September 14, 2012 at 11:58 am
“One of the conclusions we are coming to is to “Reject the Group Sunspot Number approach”
Good for you guys! I know little of this area but as an auditor I had to shake my head at how those were counted and have thought I sure would like to hear the explanation for that approach! One has to appreciate consistency but it would nice to be able to unravel that code sometime in the future.
Counting spots especially with the group number seems to be a rather crude measure and I would assume in modern times measurements of the geomagnetic field is much more objective. I see your statement the geomagnetic field variation was discovered in 1722. How confident are you in proper measuring of it through time?
Leif Svalgaard says:
September 16, 2012 at 8:44 pm
===================
Thanks, Leif.
I have been enjoying your comments of late, I’m learning.
Bill Hunter says:
September 16, 2012 at 10:07 pm
I see your statement the geomagnetic field variation was discovered in 1722. How confident are you in proper measuring of it through time?
From the 1740s it was precise enough for this purpose. An angle of about 10 arc minutes is measured and that was well within the capabilities of that time.
Leif Svalgaard says:
September 16, 2012 at 8:44 pm
u.k.(us) says:
September 16, 2012 at 8:08 pm
“We can also use the ‘name and shame’ mechanism which can be quite effective.”
Sure you want to go here ?
Yes, although it is true that you catch more flies with honey than with vinegar, but when you have caught one, you squash it. As Hugh Hudson puts it [slide 10 of http://www.leif.org/research/SSN/Hudson.pdf ] :
This group needs to take charge of the perception of SSN:
– Consensus
– Public databases and ample publications
– Propaganda that discredits any research not using the consensus SSN
Severe [but necessary] gate keeping if you will.
Hey Leif, these lines, especially those at the bottom makes my BS-meter beep.
What confuses me is, if there is no politicisation why is there need of such consensus and push and propaganda? Severe gate-keeping?
I can understand you have a new version of interpreting the old sun spots counting. OK this is the new “consensus” sunspot graphic. We know what is pressure to agree in a group. Group decisions are not always best science.
We can no longer count the way people 100, 200 years ago did? If the new method is better it will be anyhow validated with the time, what for the propaganda, the push and the gate keeping?
What for these? For the pure love for science? What are you afraid of?
Lars P. says:
September 17, 2012 at 12:03 pm
Hey Leif, these lines, especially those at the bottom makes my BS-meter beep.
Perhaps that BS-meter is badly in need of adjustment too? 🙂
What confuses me is, if there is no politicisation why is there need of such consensus and push and propaganda?
Because there are several data series out there which are different enough that it makes a difference which one you use. People then cherry-pick the one that fits their pet theory the best. This is poor science [or not science at all]. It behooves the folks responsible for producing the sunspot series to get their house in order and agree [if possible] on what is the ‘best’ according to the data we have. This is simply what we are trying to do.
Group decisions are not always best science.
In this case it will be as all data, methods, calibrations, etc will be thoroughly vetted by all members of the group.
We can no longer count the way people 100, 200 years ago did?
Of course we can. We even have the original instruments used by Wolf and successors, and they are being used to this day.
What are you afraid of?
See above. A correct measure of the long-term variation of solar activity has many practical uses, e.g. in the prediction of the next cycle, as a benchmark for theories to match, etc.
Leif Svalgaard says:
September 17, 2012 at 6:45 pm
Leif, thanks for the answer, but no adjustments to my BS-meter (thanks for the good laugh!) it is tested and works ok for 97% (75 out of 77 cases) – but it was not wrong since long, so maybe ….
“Because there are several data series out there which are different enough that it makes a difference which one you use.”
Well – it is either an imprecision of measurements – so in the error range – or wrong measurement or it is interpretation of the data. If there is interpretation of the data what we talk about, then it is a different story.
In this case it will be as all data, methods, calibrations, etc will be thoroughly vetted by all members of the group.
How does it work? If one person says 1% more here (because of…) and the other one 2% less (due to …) if they do not agree, is the result the average, weighted average or they discuss until one gives up? If there is one who does not agree is the error range increased or is he simply ignored?
But I have the impression that the results are already known from what was shown already in the thread. So what is the group discussing actually?
Of course we can. We even have the original instruments used by Wolf and successors, and they are being used to this day.
If we can then why do we need any adjustments? Why don’t we keep the same methods and measurements to keep the validity of the data? Pardon my ignorance – is this what you are trying to do?
See above. A correct measure of the long-term variation of solar activity has many practical uses, e.g. in the prediction of the next cycle, as a benchmark for theories to match, etc
Yes.
This does not justify propaganda to discredit any other interpretation. If its a matter of interpretation and not precise measurement it is a grey area where the other side may be right. I do not think in science there is any need of propaganda to discredit other research based on different data interpretation.
To my understanding this is not helping the progress of science. Quite the contrary propaganda was used to support the theory in power delaying the time until it could be challenged. Fringe theories either will be with the time discredited, or rarely gain slowly traction and are adopted.
Lars P. says:
September 18, 2012 at 1:46 pm
If there is interpretation of the data what we talk about, then it is a different story.
The data are what they are and cannot be changed and don’t have errors [if person P says see saw S spots, that is what he saw]. The problem is that no single person have observed for the past 400 years, so we have to ‘harmonize’ the different observers by referring his data to a chosen standard observer.
How does it work?
Basically the data from one observer is plotted against a standard observer. Experience shows that such plots are linear and it comes down to determined the slope of the line. There are standard ways of doing that, so no discussion or disagreement is needed or possible. We have to have everybody to sign off on the result. If there is dissent, the dissenter must show where everybody else is wrong.
But I have the impression that the results are already known from what was shown already in the thread. So what is the group discussing actually?
Not everybody [in fact only a few] has gone through ALL the details for themselves. The workshop is the means to FORCE everybody to work through ALL the data.
If we can then why do we need any adjustments? Why don’t we keep the same methods and measurements to keep the validity of the data? Pardon my ignorance – is this what you are trying to do?
The difficulty is that there is no overlap between modern observers and the early ones. What we can do is to compare the modern data to the objective measure of the UV that is afforded by the geomagnetic measurements. And to teach everybody about the geomagnetic method [which is mostly voodoo to solar observers]
If its a matter of interpretation and not precise measurement it is a grey area where the other side may be right. I do not think in science there is any need of propaganda to discredit other research based on different data interpretation.
Interpretation is too weak a word for what we are doing. ‘Calibration’ is the better word. Calibration is an objective procedure and if people do not take the trouble to understand [and follow] the whole process, then their opinion should be discredited.
To my understanding this is not helping the progress of science. Quite the contrary propaganda was used to support the theory in power delaying the time until it could be challenged. Fringe theories either will be with the time discredited, or rarely gain slowly traction and are adopted.
I hope that your understanding is now improved. What we are doing will greatly help the progress of science. To wit that everyone in this business agrees that it will. The problem is not fringe theories or suppressing of data, but to educate our ‘users’ who as long as there are several ‘semi-official’ version will cherry pick the one [right or wrong – doesn’t matter to them] that supports their own pet theories. This is what we are working on to avoid.
I notice that the MWP period of sunspots is quite a bit lower than the modern period according the the chart there. So, if the IPCC is wrong, and the sun is the primary influence on climate, should we agree that the MWP was cooler than today? Or do we invoke some other forcing that is stronger than solar which made the MWP warmer?
According to the chart, 11, 000 years ago solar activity was as high as the latter part of the 20th century. But if the proxies for this come (mainly?) from the Northern Hemisphere, isn’t that more a record of orbital dynamics, which saw increased insolation over the Northern Hemisphere at that time?
barry says:
September 19, 2012 at 9:15 pm
I notice that the MWP period of sunspots is quite a bit lower than the modern period according the the chart there.
It is very likely that the chart is wrong, see. http://www.leif.org/research/The%20long-term%20variation%20of%20solar%20activity.pdf