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.
sturgishooper says: August 8, 2014 at 2:23 pm
But in any case, evidence suggests that the longer term effect of large volcanic eruptions is winter warming over most regions,
Exactly what I found in the relation to the CET , you are also correct on the ENSO , here correlation is negative.
Sturgis, you are right. Models demonstrate an initial warming pattern, likely caused by the triggered El Nino. However, following that warming there is ample evidence in the literature of a subsequent plunge into cold weather patterns. That cold pattern stays around for a long time and has puzzled scientists. They commonly point to a slow down/disruption in the overturning circulation.
As for the number of volcanic events, I prefer using the ice core data. Why? Because I know that the type of explosion resulted in stratospheric ejecta sufficient to migrate to the poles. The following link is just one of many the explores this data obtained from ice cores around the world. You can clearly see that the LIA had quite a number of events throughout the period. The biggest one has been identified just last year.
http://climate.envsci.rutgers.edu/IVI2/
The following is a very good description of the larger events and subsequent chill. It mentions the odd warming affects as well, which is again, a well-known phenomenon that has a likely cause. I speculate that they are missing the discharge/recharge process Bob Tisdale has been working on.
http://rsta.royalsocietypublishing.org/content/364/1845/2073.full
Typing too fast makes grammar suck ast.
Pamela Gray says:
August 8, 2014 at 3:18 pm
Please present such evidence if you imagine it exists, and how this can happen when it hasn’t been observed.
Teh El Chichon eruption was followed by a super El Nino and Pinatubo by a moderate one, but no such eruption immediately preceded the super El Nino of 1997. In any case, El Ninos and La Ninas are weather events, not climate. El Ninos are slightly more common during warm phases of the climate phenomenon PDO, and La Ninas somewhat more common during the cool phases. It can’t be shown that volcanic eruptions trigger the Ninas or Nadas, although there is a correlation with submarine seismic activity in the SE Pacific.
Krakatoa was followed by the Modern Warm Period, not prolonged cooling. Pinatubo was followed by the warming of the 1990s, not cooling.
Your link was assembled by Robock, author of the study I linked. Did you actually look at his data? It shows a spike in sulfate aerosols during the Medieval Warm Period, from the 12th to the 14th century, not the Little Ice Age, during which the biggest spike is early on, during the 15th century, then at the end, during the 19th, with lesser levels during depths of the LIA, ie the Maunder Minimum or the 17th and 18th centuries and practically nothing during the cold 16th century.
Robock’s aerosol data undercut your unsupported assertion. I wonder why you linked it. Maybe his Version 2 makes your case better, but if so please show the revisions graphically, too. Thanks.
Brand new temperature reconstruction of the Little Ice Age. Notice the ups and downs of temperature swings.
http://www.the-cryosphere.net/8/639/2014/tc-8-639-2014.html
Pamela Gray says:
August 8, 2014 at 3:29 pm
Why on earth would you link to a paper on super-eruptions, the last of which occurred 26,000 years ago, during the previous glaciation, not an interglacial, and which shows that the effects even of these rare events, caused by meteor impacts, still only last for years, thus are not climatic forces?
Do you have any evidence that actually supports your baseless assertion, or only “evidence” which totally guts it?
Just an abstract. I will try to find the paper re: Volcanic Explosion El Nino Trigger. There has been a plethora of papers on this in recent years.
http://www.nature.com/nature/journal/v426/n6964/full/nature02101.html
found it
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0CFMQFjAF&url=http%3A%2F%2Fwww.meteo.psu.edu%2Fholocene%2Fpublic_html%2Fshared%2Farticles%2FAdamsetal-Nature03.pdf&ei=F1PlU6mdEYLjoATDxYK4BQ&usg=AFQjCNH8Tmk37dLdKDzsgx91JCEwGvGiWg&bvm=bv.72676100,d.cGU
Pamela Gray says:
August 8, 2014 at 3:39 pm
There is evidence that large volcanic eruptions temporarily make for cooler summers, especially during cold periods like the LIA, as happened after Tambora. But that doesn’t mean that glacial advance in general during cold periods is due to increased volcanism. An already growing glacier might grow more because of two cold summers in a row.
But that has nothing whatsoever to do with your presumed oceanic effect, leading to centuries long climate fluctuations like the Minoan Warm Period, Greek Dark Ages Cold Period, Roman Warm Period, Dark Ages Cold Period, Medieval Warm Period, Little Ice Age and Modern Warm Period, all of which had major volcanic eruptions.
You have yet to produce a single shred of evidence in support of your conjecture that increased volcanism caused the Little Ice Age. If that were the case, then it should have started in the 12th or 13th century rather than the 15th or 16th and should still be going on.
Sturgis, here ya go. 1257. It was a super big one. Not the biggest ever but this one had additionally a tremendous amount of ejecta, clearly seen in the ice core data. Scientists are beginning to recognize this eruption a possible opening door to the LIA.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CEIQFjAE&url=http%3A%2F%2Fwww.lgp.cnrs-bellevue.fr%2Fdocuments%2Fevenements%2FAbstract_samalas_en.pdf&ei=01PlU_-OA8zuoASN4YKwBQ&usg=AFQjCNG7ot8PnOl9Q7NR0m2Vac3BD8tRwg
Sturgis, why would it still be going on? That makes no sense.
The Little Ice Age was not one long cold chill. There were many ups and downs. Some decades were very warm during the Little Ice Age. It is a common mistake to consider the entire period one of cold temperatures. It was not.
Brand new paper. Just the abstract. I will try to find a preprint
http://www.pnas.org/content/111/28/10077
Pamela Gray says:
August 8, 2014 at 3:47 pm
What has driven you over to the Dark Side? Can’t possibly be search for reality, since all the evidence in the world is against your conjecture. You are now in league with Michael Mann, desperately trying to find some other excuse for the “putative” Medieval Warm Period and LIA now that his HS scam has been so thoroughly discredited.
That big eruptions might encourage a nascent El Nino to form or strengthen is plausible, since they are weather events. But he offers no more explanation or supporting evidence than you do for how eruptions every 50 to 100 years can cause climate fluctuations like the Medieval Warm Period to the LIA, especially since these transitions occur at fairly regular intervals in all interglacials (and glacials) and are clearly associated with solar activity and modulations of irradiance and magnetism.
Again, there were no more big eruptions in the LIA than in the Modern WP so far, and there was more sulfate aerosol lofted during the Medieval WP than the LIA. But there’s no convincing a true believer with fact, evidence or reason.
Sturgis, that thread has grown to a rope. However, I still think that the “disruption of the overturning circulation” issue needs to be informed with the speculation that oceans spent a great deal of time undergoing evaporation, IE energy discharge processes and not enough recharging to keep from sliding into cold regimes.
Pamela Gray says:
August 8, 2014 at 3:52 pm
Sturgis, why would it still be going on? That makes no sense.
——————–
Obviously because the number of volcanic eruptions has increased, not decreased since the LIA.
Pamela Gray says:
August 8, 2014 at 3:54 pm
The Little Ice Age was not one long cold chill. There were many ups and downs. Some decades were very warm during the Little Ice Age. It is a common mistake to consider the entire period one of cold temperatures. It was not.
———————–
You’re telling me this, after I posted the fifty year averages and decade by decade temperature breakdowns for the LIA? Do you read the comments in the posts to which you respond?
The ups and downs in the LIA further give the lie to your baseless assertion. There were no big volcanic eruptions during the depths of the LIA nor during he rapid rebound from those depths. Try actually looking at the record before spewing pointless pap.
The closest big volcanic eruption to the depths of the Maunder Minimum during c. 1690 to 1710 occurred at 1660 +/- 20 years, so could have been as late as 1680, but probably wasn’t. In any case, it was nothing special. There wasn’t another one until about 1783.
Look at your own linked graph, for crying out loud!
Sturgis, the ice core data I referred to (which is the data set used by ice core scientists) demonstrates that stratospheric ejecta was far greater during the Little Ice Age than during the previous Medieval Warm Period, so I don’t get your comment about the amount of sulfate aerosol during the MWP. And most scientists now accept the 1257 eruption as having occurred when the MWP was over and may have even been its demise.
Pamela Gray says:
August 8, 2014 at 4:01 pm
If you think you can demonstrate physically how your speculation would work, please do the work and write it up. Until then, it’s nothing but idle conjecture.
Volcanic modulation of insolation leading to prompt summer cooling and longer term winter warming for a few years at most are weather events. Volcanoes aren’t a pimple on the posterior of the vast energy fluctuations produced by the sun’s internal variability and the more potent, longer-lasting, indeed continuous, other modulating sources.
I tell you what Sturgis, write a rebuttal to the journals that have published the now too many to link to papers about how you think they are wrong. These studies are well done and I think are on the right track. But be as upset as you wish that I do not think your comments here to be equivalent rebuttal to the literature review.
This is a keen area of interest for me and I keep current on the literature. It was very exciting to see that 1257 volcano identified. It has sparked a renewed interest in the Little Ice Age and I think will help us understand its causes, devastations, and recovery.
Pamela Gray says:
August 8, 2014 at 4:08 pm
I know the “ice core scientists” to whom you refer. Who says that the LIA started in the 13th century? Mann? Of course he’d like that, but it’s yet another outrageous lie. Disappointing that you’ve bought into such blatant mendacity.
Since you acknowledge that the Medieval Warm Period and LIA have ups and downs, here for the umpteenth, they are for the CET and Manley’s reconstruction of it farther back in time, from which data a real climate scientist, Lamb, identified the MWP & LIA (last number is the annual average):
800-1000 3.5 3.5 15.9 15.9 9.2
1000-1 I00 3.7 3.7 (16.2) 16.2 9.4
1100-1150 3.5 3.5 (16.2) 16.5 9.6
1150-1200 3.9 4.2 (16.3) 16.7 10.2
1200-1250 3.8 4.1 (16.3) 16.7 10.1
1250-1300 3.9 4.2 (16.3) 16.7 10.2
1300-1350 3.6 3.8 15.9 16.2 9.8
1350-1400 3.6 3.8 15.7 15.9 9.5
1400-1450 3.4 3.4 15.8 15.8 9.1
1450-1500 3.5 3.5 15.6 15.6 9.0
1500-1550~ 3.8 3.8 15.9 15.9 9.3
1550-1600 3.2 3.2 (15.3) 15.3 8.8
1600-1650 3.2 3.2 (15.4) 15.4 8.8
1650-1700 a 3.1 3.1 (15.3) 15.3 8.7
1700-17508 3.7 3.7 15.9 15.9 9.24
1750-1800 3.4 3.4 15.9 15.9 9.06
1800-1850 3.5 3.5 15.6 15.6 9.12
1850-1900 3.8 3.8 15.7 15.7 9.12
1900-1950 4.2 4.2 15.8 15.8 9.41
Please note that tied for the warmest 50 year interval is the time in which you & your new best buddy Mickey have decided to revise climate history into the LIA. And the following 100 years were also warmer than the early Medieval Warming Period and much more so than the whole of the LIA.
Only in Stalin’s USSR and modern “climate science” could such revisionism tolerate a rewrite of history of this magnitude.
Pamela Gray says:
August 8, 2014 at 4:14 pm
Again, as is your SOP, you “cite” anonymous studies. If you know of them, trot them out. If not, then don’t mention them. Vague hand waving doesn’t cut it in science. Where are all these “peer reviewed papers”? I showed you mine. When will you show me yours? Until then, as always, you’ve got nothing, noodnik, nada, zilch, zip, but idle (and I do mean idle) conjecture.
I’ll employ your method and mention the sure to be far more numerous papers showing the solar influence on climate change, some of which I’ve already presented and to which you had no response.
Sturgis, you are a rather unpleasant person if you take your rebuttal style as representative if your persona. But that aside, I can see you are someone who clearly will not consider the entire breadth of possible causes of events that form the body of this blog, preferring your solar link. Nonetheless, time will tell the difference between us.
Re: Mann. In case you are wondering, I have commented many times about Mann’s reconstruction and I do not recommend its use. That does not negate the excellent study done on alpine glaciers. I’ve learned to discern research results. It is not uncommon that published research has its strengths and weaknesses. It is rather the rule, not the exception. You learn to take what is good and critique what is not so good. Heck, I can’t read my own one claim to fame without pointing out its weaknesses. But it has been replicated using different methods yet the results were the same. So even with its weaknesses, my study has stood the test. And as a result of my experience, I can tell you plain and straight, one needs cojones to do research and publish, whether it turns out good or bad. I had beginners luck.
Pamela Gray says:
August 8, 2014 at 4:34 pm
Mann’s climatic conclusion is totally unsupported by his glacier analysis, yet that’s the part that you like.
I have considered and still do consider every possible plausible explanation for decadal, centennial and millennial climatic cycles. Having done so, I can reject the role of volcanism in causing these observed cycles. Volcanoes can and do affect weather within climatic cycles but there is no instance in this or any other interglacial of single volcanoes, even the very biggest, as shown in your own link, “causing” a centennial or millennial, ie D/O or Bond Cycle.
Not even the Toba supervolcano some 74,000 years ago, which nearly wiped out humanity, had any lasting climatic effect, although it occurred well into a glacial.
Increased volcanism lasting millennia have been implicated in past climatic changes, even catastrophes like mass extinctions, but the causes of the Permian/Triassic and Triassic/Jurassic events remain controversial. The Siberian Traps and Central Atlantic Magmatic Province (start of Pangaea breakup) have been implicated, however.
Climatic effect even of Toba limited at best, and might not even have stressed humans as much as suggested:
http://www.newscientist.com/article/dn23458-supervolcano-eruptions-may-not-be-so-deadly-after-all.html#.U-VrcKNupmc
Involves modeling, but no record of climatic effect in geologic or paleoproxy records. Robock thinks maybe the effect was too brief to show up.