This is interesting. A quick cooling in Europe together with an increase in humidity and particularly in windiness was found to coincide with a long-term reduction in solar activity 2800 years ago during something called the “Homeric minimum”.
The paper published in Nature Geoscience suggests that solar grand minima was the trigger for cooling of the climate in Europe. Approximately 2800 years ago, one of these Grand Solar Minima, the Homeric Minimum, caused a distinct climatic change in less than a decade in Western Europe. While they talk about UV, the forcing mechanisms still are unclear but the evidence in this paper suggests that solar effects are significant. Dr. Leif Svalgaard sent me the notice of the paper, and included this graph which he says:
Attached is one of the better reconstruction of solar activity.
There are, of course, several other excursions not mentioned, e.g. the more severe one around 650 AD
Here’s the abstract, bold mine:
Regional atmospheric circulation shifts induced by a grand solar minimum
by Celia Martin-Puertas, Katja Matthes, Achim Brauer, Raimund Muscheler, Felicitas Hansen, Christof Petrick, Ala Aldahan, Göran Possnert & Bas van Geel
Nature Geoscience (2012) doi:10.1038/ngeo1460
Large changes in solar ultraviolet radiation can indirectly affect climate1 by inducing atmospheric changes. Specifically, it has been suggested that centennial-scale climate variability during the Holocene epoch was controlled by the Sun2, 3. However, the amplitude of solar forcing is small when compared with the climatic effects and, without reliable data sets, it is unclear which feedback mechanisms could have amplified the forcing. Here we analyse annually laminated sediments of Lake Meerfelder Maar, Germany, to derive variations in wind strength and the rate of 10Be accumulation, a proxy for solar activity, from 3,300 to 2,000 years before present. We find a sharp increase in windiness and cosmogenic 10Be deposition 2,759 ± 39 varve years before present and a reduction in both entities 199 ± 9 annual layers later. We infer that the atmospheric circulation reacted abruptly and in phase with the solar minimum. A shift in atmospheric circulation in response to changes in solar activity is broadly consistent with atmospheric circulation patterns in long-term climate model simulations, and in reanalysis data that assimilate observations from recent solar minima into a climate model. We conclude that changes in atmospheric circulation amplified the solar signal and caused abrupt climate change about 2,800 years ago, coincident with a grand solar minimum.
UPDATE: Here’s the press release from the Helmholtz Association of German Research Centres.
Climatic effects of a solar minimum
A grand solar minimum and the climate response recorded for the first time in the same climate archive highlights the need for a more differentiated approach to solar radiation
An abrupt cooling in Europe together with an increase in humidity and particularly in windiness coincided with a sustained reduction in solar activity 2800 years ago. Scientists from the German Research Centre for Geosciences GFZ in collaboration with Swedish and Dutch colleagues provide evidence for a direct solar-climate linkage on centennial timescales. Using the most modern methodological approach, they analysed sediments from Lake Meerfelder Maar, a maar lake in the Eifel/Germany, to determine annual variations in climate proxies and solar activity.
The study published online this week in Nature Geosience (06/05/2012) reports the climatic change that occurred at the beginning of the pre-Roman Iron Age and demonstrates that especially the so-called Grand Minima of solar activity can affect climate conditions in western Europe through changes in regional atmospheric circulation pattern. Around 2800 years ago, one of these Grand Solar Minima, the Homeric Minimum, caused a distinct climatic change in less than a decade in Western Europe.
The exceptional seasonally laminated sediments from the studied maar lake allow a precise dating even of short-term climate changes. The results show for a 200 year long period strongly increased springtime winds during a period of cool and wet climate in Europe. In combination with model studies they suggest a mechanism that can explain the relation between a weak sun and climate change. “The change and strengthening of the tropospheric wind systems likely is related to stratospheric processes which in turn are affected by the ultraviolet radiation” explains Achim Brauer (GFZ), the initiator of the study. “This complex chain of processes thus acts as a positive feedback mechanism that could explain why assumingly too small variations in solar activity have caused regional climate changes.”
Albeit those findings cannot be directly transferred to future projections because the current climate is additionally affected by anthropogenic forcing, they provide clear evidence for still poorly understood aspects of the climate system, emphasizes Achim Brauer. In particular, further investigations are required with a focus on the climatic consequences of changes in different wavelengths of the solar spectrum. Only when the mechanisms of solar-climate links are better understood a reliable estimate of the potential effects of the next Grand solar minimum in a world of anthropogenic climate change will be possible. In this respect, well-dated annually laminated lake sediments are also in future of crucial importance for these studies.
Therefore, scientists from the German Research Centre for Geosciences (GFZ) and other institutions search for such archives around the world in order to to obtain a more accurate approach to the solar-climate relationship and the different regional responses.
Celia Martin-Puertas, Katja Matthes, Achim Brauer, Raimund Muscheler, Felicitas Hansen, Christof Petrick, Ala Aldahan, Göran Possnert and Bas van Geel: “Regional atmospheric circulation shifts induced by a grand solar minimum”, Nature Geoscience, DOI 10.1038/NGEO1460
Pictures of Eifel maar lakes and drilling can be found here:
http://www.gfz-potsdam.de/portal/gfz/Public+Relations/M40-Bildarchiv/Bildergalerie+Klimaforschung
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crosspatch says:
May 7, 2012 at 10:16 am
UV penetrates deepest into ice and water. Even at the point in depth where there is no visible light from the sun, there is still UV. I believe, and this is just my own personal belief, that changes in UV light have a significant impact on both ocean energy content and the melting of ice.
________________________
Here are the graphs illustrating your point.
http://lasp.colorado.edu/sorce/images/instruments/sim/fig01.gif
http://www.klimaatfraude.info/images/sverdrup.gif
Dutch newspaper Trouw interviewed Prof. Bas van Geel:
http://translate.google.nl/translate?sl=nl&tl=en&js=n&prev=_t&hl=nl&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.trouw.nl%2Ftr%2Fnl%2F4332%2FGroen%2Farticle%2Fdetail%2F3251521%2F2012%2F05%2F07%2FInvloed-van-zon-veel-groter-dan-klimaatpanel-ons-wil-doen-geloven.dhtml
Zac,
Don’t you know that the anwer to to any problem is, More Taxes. They do NOT spend it on climate now, so why should NOT spending it on the unchangable Sun, make any difference? If anything that give a perpetual reason to spend more. The answer is More Taxes!
Smokey says:
May 7, 2012 at 11:11 am
…..my suggestion to NASA would be to transfer Mr. Perlwitz to Muslim Outreach. Because it is clear that basic science goes right over Mr. Perlwitz’ head.
________________________________
Excellent suggestion Smokey. One can understand why NASA retirees are embarrassed.
RichieP says: @ur momisugly May 7, 2012 at 1:20 pm
….BTW, shall we just presume Perlwitz (many puns occur to me) is the undergrad intern at NASA? S/he certainly shows all the signs. Even I, a non-scientist, knows what the Null Hypothesis is about. Where do they get them from?
_________________________
A sad comment on our current education system.
FWIW, I have more interest in history and am learning more history now than I ever did when I was young.
Odd that the sediment cores retrieved from the lake would only cover dates older than 2000 yrs. Still, even if the 650 A.D. minimum is outside of their time period, there is another lesser minimum at about 400 B.C. that is in their data set. (The “Platonic minimum” perhaps?) I wonder if their full paper says anything about this episode.
Jan P. Perlwitz says:
May 7, 2012 at 9:48 am
“Sorry to spoil the party that seems to be developing here, but this paper is about regional climate change in Europe […]”
Brauer and his modeling gang in this case had to fudge their models in such a way that the model, on one hand, shows agreement with the proxy study while on the other hand does not disturb the IPCC’s basic tenets.
THIS IS EASY TO DO when you have enough parameters, and you and I know it.
RichieP at May 7, 2012 at 1:20 pm wrote:
What about, instead of attacking my person, by disseminating falsehoods about me, you try to get educated? For instance, you could start with reading Thomas Kuhn and/or Paul Feyerabend to learn something about modern epistemological theory that is relevant for understanding the scientific process, even if you are a non-scientist.
Jan P. Perlwitz says:
“…there is nothing in there that is in contradiction to that greenhouse gases have been the dominant driver for the observed global warming over the last 35 years…”
And so, since the laws of nature are constant, and greenhouse gasses are the dominat driver of climate we are left with what, dinasour farts? to explain the paleoclimate.
As I pointed out, Mr. Perlwitz does not possess the necessary rigor for the Scientific Method. Instead, he believes in the touchy-feely pseudo-science that Kuhn and Ravetz preach.
Weak minds gravitate to Post-Normal Science. Perlwitz should do a keyword search for ‘Ravetz’ to see how thoroughly that bunkum was deconstructed here. PNS is emotion-based anti-science. It is no wonder that someone who admittedly doesn’t understand the Null Hypothesis is attracted to it.
Gail Combs at May 7, 2012 at 2:20 pm wrote:
The point I was making was that particularly cold winters in parts of the Northern Hemisphere and a largely positive globally averaged temperature anomaly are not in contradiction to each other. I took the year 2010 as an example for such a case. The cold winter in 2009/2010 and 2010/2011 in some regions were related to circulation anomalies, which distributed heat from the lower to high latitudes differently compared to other years, whereas the global energy balance is more important for the globally averaged temperature anomaly.
On what data is your assertion based, according to which the globally averaged temperature anomaly was larger in the year 1933 than in the year 2010?
As for the year 1998 (I guess that’s the year you meant, not 1999) compared to the year 2010. 1998 was a year with a very strong El Nino, and solar activity was closer to the solar maximum. Greenhouse gas forcing, solar forcing, and El Nino acted all in the same direction. 2010 was a year right after a prolonged solar activity minimum, which was also somewhat deeper than previous minima. There was an El Nino at the end of 2009, which was weaker than the one of 1998, after a couple of La Nina years, and which was followed by another La Nina in 2010. So, only greenhouse gas forcing acted clearly in direction of warming. Solar activity counteracted it, and the El Nino/La Nina pattern also acted somewhat toward a cooling in the second half of the decade. Nevertheless 2010 was one of the warmest years on record at least since 1880, other years in the first decade of the new millennium were among the warmest year too, and the first decade was the warmest decade on record. So, I argue that this rather strengthens the case for global warming due to greenhouse gases, instead of weakening it.
I would say, in contrast to the view of all the ones here who claim a (drastic) global cooling was imminent, it is much more likely that we will see a new warm record of the globally averaged surface temperature anomaly within a few years, when there is a new solar maximum, even if it is smaller than the previous one, and if there is also a new El Nino at the same time.
I do not expect that such predictions like the one in the manuscript by Solheim et al., who predict a temperature drop, averaged over all years of the solar cycle 24, of 0.9 K for the Northern Hemisphere, and 0.3 to 0.5 K (or so, if I remember right) for the whole globe, will become true. I rather expect that those predictions will utterly fail.
If they became true I would have to strongly rethink my understanding of the workings of the Earth system, which I will do in this case. Will the ones here who believe in those predictions, like the ones by Solheim et al., do a rethinking of their understanding of climate, if those predictions fail, and I am right with my expectation?
Richdo says at May 7, 2012 at 4:07 pm:
I said greenhouse gases have been the dominant driver for the global warming over the last 35 years. You even quoted this! They have been the dominant driver over the last 35 years due to the strong increase in the greenhouse gas mixing ratio from anthropogenic emissions in the second half of the 20th century leading to an increase in the radiative forcing, which amounts currently to about 0.25 W/m^2 per decade at the current rate of increase. I didn’t say anything about Paleoclimate. The importance of greenhouse gases as driver for climate change depends on their rate of change over time, and the magnitude of the forcing change from this, in comparison to forcings by other climate drivers.
DirkH at May 7, 2012 at 3:25 pm wrote:
And how have you logically deduced your assertion that they did “fudge their models” for the purpose you claim? You don’t like their results, therefore the models must be fudged? Like this?
A quick cooling in Europe together with an increase in humidity and particularly in windiness….
I would be very surprised if you could derive humidity from lake sediments. I assume they have some measure that shows increased precipitation and assume its due to increased humidity, which is an error in my view.
Increased precipitation could, and likely did, result from increased GCRs/aerosols.
Its been discussed here before, but its possible the term Dark Ages originated because the period was literally darker from more cloud and perhaps volcanic aerosols.
This is the earliest know use of the term.
Petrarch in the 1330s.[3][6] Writing of those who had come before him, he said: “Amidst the errors there shone forth men of genius; no less keen were their eyes, although they were surrounded by darkness and dense gloom“.
Albeit those findings cannot be directly transferred to future projections because the current climate is additionally affected by anthropogenic forcing, they provide clear evidence for still poorly understood aspects of the climate system, emphasizes Achim Brauer.
===
LOL
Avoiding losing all their research grants… in extremis.
Mr. Perlwitz says that GHG’s “have been the dominant driver over the last 35 years due to the strong increase in the greenhouse gas mixing ratio from anthropogenic emissions in the second half of the 20th century leading to an increase in the radiative forcing, which amounts currently to about 0.25 W/m^2 per decade at the current rate of increase.”
I note for the record that Perlwitz’ “0.25 W/m^2” number is entirely model-based, as is his preposterous belief that human emissions can be quantified to one-quarter of a Watt per square meter. Nonsense. There are no testable, empirical measurements verifying that number. It is a complete fiction. With climate models it is: Garbage In, Gospel Out. It is neither testable nor falsifiable in the real world. “0.25 W/m^2” is a computer artefact of models, and nothing more.
Further, the climate Null Hypothesis falsifies the alternative CO2=CAGW conjecture. As climatologist Roy Spencer points out, “No one has falsified the hypothesis that the observed temperature changes are a consequence of natural variability.” The Null Hypothesis has never been falsified.
Kevin Trenberth is so bothered by his inability to falsify the Null Hypothesis that he stated: “The Null Hypothesis should now be reversed, thereby placing the burden of proof on showing that there is no human influence.” But of course, that turns the Scientific Method on its head, by placing the onus on scientific skeptics to, in effect, prove a negative. That is witch doctor talk, not science.
Even Trenberth has gotten no traction for that bit of pseudo-science. But it could be worse: Trenberth might have shown that he was as ignorant of the existence of the Null Hypothesis as Mr. Perlwitz. Trenberth at least understands the basic concept.
Stephen Wilde
Large changes in solar ultraviolet radiation can indirectly affect climate1 by inducing atmospheric changes. …. We infer that the atmospheric circulation reacted abruptly and in phase with the solar minimum. A shift in atmospheric circulation in response to changes in solar activity …
This all looks like your New Climate Model.
Jan P. Perlwitz says:
May 7, 2012 at 4:49 pm
Gail Combs at May 7, 2012 at 2:20 pm wrote:
As for the year 1998 (I guess that’s the year you meant, not 1999) compared to the year 2010. 1998 was a year with a very strong El Nino, and solar activity was closer to the solar maximum. Greenhouse gas forcing, solar forcing, and El Nino acted all in the same direction. 2010 was a year right after a prolonged solar activity minimum, which was also somewhat deeper than previous minima. There was an El Nino at the end of 2009, which was weaker than the one of 1998, after a couple of La Nina years, and which was followed by another La Nina in 2010. So, only greenhouse gas forcing acted clearly in direction of warming. Solar activity counteracted it, and the El Nino/La Nina pattern also acted somewhat toward a cooling in the second half of the decade. Nevertheless 2010 was one of the warmest years on record at least since 1880, other years in the first decade of the new millennium were among the warmest year too, and the first decade was the warmest decade on record. So, I argue that this rather strengthens the case for global warming due to greenhouse gases, instead of weakening it.
We humans are naturally story-tellers, from a complex morass of evidence we extract a simplifying story that will at once impress the audience and advance our socio-economic position. That’s how intelligence has evolved. However in science we need to consciously oppose this trend since it leads us up the garden path too often.
You have woven a nice story about how just 3 things – like Rublyev’s divine trinity – together dictate the climate – greenhouse forcing, solar forcing and ENSO. But there are so many others that could – to borrow your expression – “spoil the party”. Ocean deep circulation has a 1000 year timecourse and we know almost nothing about long term variations in upwelling linked to THC patterns. Also, if as is likely the global atmosphere-ocean system exhibits chaotic non-equilibrium pattern behaviour, then the SYSTEM ITSELF can easily throw up major variations without ANY outside forcing. In fact this slavish recourse to the concept of a forcing for everything that happens reveals a failure to understand this possiblity of spontaneous intrinsic pattern without forcing. This is one of the biggest blind-spots of climate science.
But I applaud your appeal to future climate development as the proof of who is right and wrong, and adherence to Popperian “falsifiable” science in contrast to many in the AGW camp.
I’ll join phlogiston in applauding Jan P. Perlwitz for saying that evidence could change his mind. An attitude sorely lacking in CAGW circles. In a recent ABC survey, I answered “Strongly agree” to the question “How much do you agree or disagree with the following statement: “I could easily change my mind about global warming.”“, in spite of having indicated a deep scepticism of AGW in other questions, because no matter how personally painful a change of mind might be, I still have to be prepared at all times to recognise actual evidence.
Jan P. Perlwitz – in essence I accept your challenge, but not quite as you put it, with the sceptics’ case based essentially on a prediction by Solheim et al. That prediction depends on a certain behaviour by the sun, so if the sun does not behave as predicted then the climate cannot be expected to behave as predicted either. Also, I have not done or checked the calculations so I don’t know how much cooling to expect (and I seriously doubt whether anyone else does). But if the sun goes into and stays in low activity for a number of years, and if the ocean heat content also rises to the models’ predicted levels, then I would (in your words) ‘have to strongly rethink my understanding of the workings of the Earth system, which I will do’. This applies regardless of what CO2 levels do.
OTOH, no matter what the sun does, if CO2 levels stay up or increase and if the temperature continues below the models’ lowest estimates (for those CO2 levels), then I will welcome your re-think.
We don’t have a cut-off date for the re-think, but maybe the start of solar cycle 25 would give enough time? (That’s still a long wait, and I suspect that it will all be over before then.)
A couple of observations about that Steinhilber reconstruction. First, it estimates 20th century solar activity to be rather high compared to 18th and 19th century solar activity, in contrast to Leif’s oft-stated assessment that 20th century activity wasn’t significantly higher. I looked into the sources of Steinhilber’s reconstruction to see if the observational sunspot numbers were used to calibrate the later part of the record (which would allow what bias there may be in Waldmeier’s post-1945 counting techniques to bias the reconstruction) and the answer seems to be no.
The reconstruction IS a composite, joining isotope proxies with observed neutron counts, but sunspot numbers do not seem to have been used to calibrate the joining of the two records. The construction goes back to Steinhilber 2008, which states:
Was there some period of overlap between the isotope and neutron records that they could use to calibrate the joining? It’s not clear, but looking through the paper, they are not using observed sunspot numbers for calibration. Even so, their reconstruction doesn’t look so different from the observed numbers. Perhaps the Waldmeier counting problem is not as big as Leif has been thinking?
A second interesting feature of Steinhilber’s reconstruction is that its deepest LIA minimum (by a substantial margin) is Sporer (centered a bit before 1500), while it estimates Wolf and Maunder to be approximately the same depth and duration as each other. This seems a bit different from earlier reconstructions, which show Wolf not as deep, and show Sporer pretty similar to Maunder, but not deeper and longer (figure 2, Usoskin 2003).
If Steinhilber’s Sporer estimate is right, how could the sun go magnetically quieter than during Maunder, when almost no sunspots were seen for 70 yrs? We got a picture of what that looks like in 08, with the surface of the sun looking like a even field of wheat gently waving in the breeze. Does the wheat get shorter?
The “Homeric minimum” is hindcast with precision when looking at solar AM. This is no mean feat as there can be no room for error. The solar path and planet angles of the Homeric Minimum are nearly the same as the Sporer Minimum and offer clear evidence of a repeating pattern. This pattern doesn’t come along all that often.
http://tinyurl.com/2dg9u22/images/type_a_b.png
http://tinyurl.com/2dg9u22/images/c14nujs1.jpg
Mike Jonas says:
May 7, 2012 at 1:27 pm
“the amplitude of solar forcing is small”
That assumes that TSI is the proxy for solar forcing. Einstein won his Nobel for showing that frequency, not intensity determines the energy level of photons. Yet solar science concentrates on a hopelessly misleading proxy to base its climate conclusions.
For example, a person can sit all day under a 100 W/m2 IR, but if you change that to a 100 W/m2 UV lamp it can prove fatal. The exact same solar intensity in W/m2 used by solar science to measure the effect of the sun on climate. Totally different effect. Ignored by science in their calculations of energy balance.
Why not use magnetic field strength as a proxy for solar activity? We know that climate undergoes massive change when the magnetic fields on earth reverse. The earth’s magnetic field is puny in comparison to the sun’s. While solar intensity remains fairly constant, the same cannot be said for the sun’s magnetic field.
@Leif:
That 650 AD date is about 1470 BP. (inside the error band of my ability to read the scale on the graph from which the 650 date is estimated.)
You might recognize that as Bond Event 1, or The Migration Era Pessimum. (Wiki has since purged the usage of ‘pessimum’ for that cold period in favor of just “migration period”. Doesn’t sound so cold and miserable that way:
http://en.wikipedia.org/wiki/Migration_Period
that has been largely ‘sanitized’ of any reference to the cold then.
http://chiefio.wordpress.com/2009/04/06/bond-event-zero/
http://www.multilingualarchive.com/ma/enwiki/en/Migration_Period_Pessimum
So yeah, it was cold, centered on that down spike in solar activity then, too.
That “Homeric Minimum” 2800 BP could also be called Bond Event 2, AKA the Iron Age Cold Period:
Oddly, that wiki has not been sterilized, so I’ll quote it here:
http://en.wikipedia.org/wiki/Iron_Age_Cold_Epoch
Not much in that wiki, though.
That dip about 1600 we already know as the Little Ice Age…
So moving on back, at about 5500 – 5800 B P there are some more dips.
http://en.wikipedia.org/wiki/5.9_kiloyear_event
Yup, another cold time…
Now it’s a bit less precise as you go back further in time. There’s the 8.2 Kiloyear even, that shows up as that dip about 6200-6400 BC, but there is also a dip about 7200 BP or 5200 BC. What about that?
Well….
one of them is another Bond Event. The other one shows up as a cold dip in a temperature chart I’ve got stuck in this posting:
https://chiefio.wordpress.com/2011/12/13/8-2-kiloyear-event-and-you/
http://upload.wikimedia.org/wikipedia/commons/5/57/Greenland_Gisp2_Temperature.svg
All in all, a rather strong set of correlations…
But correlation is not causality, so I’m sure there’s some other explanation…
The case for solar induced UV changes that affect climate is growing by the month. We are also witnessing it in real time over the past few winters in particular. As the heat leaves the oceans this will induce further cooling.
UV can vary by 30-100% over the cycle depending on the wave length, current UV levels are substantially lower than those experienced typically at this point in the solar cycle. All wave lengths contribute to altering ozone content at different levels of the atmosphere.
http://tinyurl.com/2dg9u22/?q=node/236