From NCAR/UCAR, they’re still trying to stamp out solar influence as a potential cause of the Little Ice Age. One of the things I wonder about is that during low sunspot activity, does the reduced solar-magnetic influence have any effect on Earth’s plate tectoncs and vulcanism? Does a reduced solar-magnetic influence prompt more volcanism? We may get the answer to this question in the coming years as the Ap solar-geomagnetic activity index is at an all-time low in the records.
Study may answer longstanding questions about Little Ice Age
BOULDER — A new international study may answer contentious questions about the onset and persistence of Earth’s Little Ice Age, a period of widespread cooling that lasted for hundreds of years until the late 19th century.
The study, led by the University of Colorado Boulder with co-authors at the National Center for Atmospheric Research (NCAR) and other organizations, suggests that an unusual, 50-year-long episode of four massive tropical volcanic eruptions triggered the Little Ice Age between 1275 and 1300 A.D. The persistence of cold summers following the eruptions is best explained by a subsequent expansion of sea ice and a related weakening of Atlantic currents, according to computer simulations conducted for the study.
The study, which used analyses of patterns of dead vegetation, ice and sediment core data, and powerful computer climate models, provides new evidence in a longstanding scientific debate over the onset of the Little Ice Age. Scientists have theorized that the Little Ice Age was caused by decreased summer solar radiation, erupting volcanoes that cooled the planet by ejecting sulfates and other aerosol particles that reflected sunlight back into space, or a combination of the two.
“This is the first time anyone has clearly identified the specific onset of the cold times marking the start of the Little Ice Age,” says lead author Gifford Miller of the University of Colorado Boulder. “We also have provided an understandable climate feedback system that explains how this cold period could be sustained for a long period of time. If the climate system is hit again and again by cold conditions over a relatively short period—in this case, from volcanic eruptions—there appears to be a cumulative cooling effect.”
“Our simulations showed that the volcanic eruptions may have had a profound cooling effect,” says NCAR scientist Bette Otto-Bliesner, a co-author of the study. “The eruptions could have triggered a chain reaction, affecting sea ice and ocean currents in a way that lowered temperatures for centuries.”
The study appears this week in Geophysical Research Letters. The research team includes co-authors from the University of Iceland, the University of California Irvine, and the University of Edinburgh in Scotland. The study was funded in part by the National Science Foundation, NCAR’s sponsor, and the Icelandic Science Foundation.
Far-flung regions of ice
Scientific estimates regarding the onset of the Little Ice Age range from the 13th century to the 16th century, but there is little consensus, Miller says. Although the cooling temperatures may have affected places as far away as South America and China, they were particularly evident in northern Europe. Advancing glaciers in mountain valleys destroyed towns, and paintings from the period depict people ice-skating on the Thames River in London and canals in the Netherlands, places that were ice-free before and after the Little Ice Age.
“The dominant way scientists have defined the Little Ice Age is by the expansion of big valley glaciers in the Alps and in Norway,” says Miller, a fellow at CU’s Institute of Arctic and Alpine Research. “But the time in which European glaciers advanced far enough to demolish villages would have been long after the onset of the cold period.”
Miller and his colleagues radiocarbon-dated roughly 150 samples of dead plant material with roots intact, collected from beneath receding margins of ice caps on Baffin Island in the Canadian Arctic. They found a large cluster of “kill dates” between 1275 and 1300 A.D., indicating the plants had been frozen and engulfed by ice during a relatively sudden event.
The team saw a second spike in plant kill dates at about 1450 A.D., indicating the quick onset of a second major cooling event.
To broaden the study, the researchers analyzed sediment cores from a glacial lake linked to the 367-square-mile Langjökull ice cap in the central highlands of Iceland that reaches nearly a mile high. The annual layers in the cores—which can be reliably dated by using tephra deposits from known historic volcanic eruptions on Iceland going back more than 1,000 years—suddenly became thicker in the late 13th century and again in the 15th century due to increased erosion caused by the expansion of the ice cap as the climate cooled.
“That showed us the signal we got from Baffin Island was not just a local signal, it was a North Atlantic signal,” Miller says. “This gave us a great deal more confidence that there was a major perturbation to the Northern Hemisphere climate near the end of the 13th century.”
The team used the Community Climate System Model, which was developed by scientists at NCAR and the Department of Energy with colleagues at other organizations, to test the effects of volcanic cooling on Arctic sea ice extent and mass. The model, which simulated various sea ice conditions from about 1150 to 1700 A.D., showed several large, closely spaced eruptions could have cooled the Northern Hemisphere enough to trigger the expansion of Arctic sea ice.
The model showed that sustained cooling from volcanoes would have sent some of the expanding Arctic sea ice down along the eastern coast of Greenland until it eventually melted in the North Atlantic. Since sea ice contains almost no salt, when it melted the surface water became less dense, preventing it from mixing with deeper North Atlantic water. This weakened heat transport back to the Arctic and created a self-sustaining feedback on the sea ice long after the effects of the volcanic aerosols subsided, according to the simulations.
The researchers set solar radiation at a constant level in the climate models. The simulations indicated that the Little Ice Age likely would have occurred without decreased summer solar radiation at the time, Miller says.
About the article
Title: Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks
Authors: Gifford Miller, Áslaug Geirsdóttir, Yafang Zhong, Darren J. Larsen, Bette L. Otto-Bliesner, Marika M. Holland, David A. Bailey, Kurt A. Refsnider, Scott J. Lehman, John R. Southon, Chance Anderson, Helgi Bjornsson, Thorvaldur Thordarson,
Publication: Geophysical Research Letters
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Here’s the paper abstract, the actual paper is not yet available (another science by press release that we can’t check).
http://www.agu.org/pubs/crossref/pip/2011GL050168.shtml
GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2011GL050168
Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks
- Little Ice Age began abruptly in two steps
- Decadally paced explosive volcanism can explain the onset
- A sea-ice/ocean feedback can sustain the abrupt cooling
Gifford H Miller
Aslaug Geirsdottir
Yafang Zhong
Darren J Larsen
Bette L Otto-Bliesner
Marika M Holland
David Anthony Bailey
Kurt A. Refsnider
Scott J. Lehman
John R. Southon
Chance Anderson
Helgi Björnsson
Thorvaldur Thordarson
Northern Hemisphere summer temperatures over the past 8000 years have been paced by the slow decrease in summer insolation resulting from the precession of the equinoxes. However, the causes of superposed century-scale cold summer anomalies, of which the Little Ice Age (LIA) is the most extreme, remain debated, largely because the natural forcings are either weak or, in the case of volcanism, short lived. Here we present precisely dated records of ice-cap growth from Arctic Canada and Iceland showing that LIA summer cold and ice growth began abruptly between 1275 and 1300 AD, followed by a substantial intensification 1430-1455 AD. Intervals of sudden ice growth coincide with two of the most volcanically perturbed half centuries of the past millennium. A transient climate model simulation shows that explosive volcanism produces abrupt summer cooling at these times, and that cold summers can be maintained by sea-ice/ocean feedbacks long after volcanic aerosols are removed. Our results suggest that the onset of the LIA can be linked to an unusual 50-year-long episode with four large sulfur-rich explosive eruptions, each with global sulfate loading >60 Tg. The persistence of cold summers is best explained by consequent sea-ice/ocean feedbacks during a hemispheric summer insolation minimum; large changes in solar irradiance are not required.
Received 29 November 2011; accepted 30 December 2011.
Citation: Miller, G. H., et al. (2012), Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks, Geophys. Res. Lett., doi:10.1029/2011GL050168, in press.
“…powerful computer climate models, provides new evidence in a longstanding scientific debate over the onset of the Little Ice Age. …”
[emphasis added]
While models may be very useful in making a decision or judgement call, it seems to me that the models cannot provide evidence of anything.
And anyway, I’m certainly glad that they did not use “wimpy” computer models. /snark
“The researchers set solar radiation at a constant level in the climate models. ”
Except that solar radiation wasn’t at a constant level. You can also set the tree ring data at a constant level too, and then come up with the trend you want to show at the next IPCC conference. Poor old sun, never gets the recognition it deserves, Galilieo all over again.
In order to give this study some perspective, the authors should list all volcanic eruptions between say 1400 and 1900, the historical written evidence for these including death toll and an estimate of the amount of material injected into the atmosphere.
Given that the two biggest eruptions that took place these past 1000 years took place in the 19th century (Tambora in 1815 with 71,000 deaths and Krakatoa in 1883 with 35,000 deaths not forgetting Galunggung 1822 with 4,000 deaths), why did the LIA not extend further into the 19th century?
Camburn says:
January 30, 2012 at 1:31 pm
Concerning a Bong Type Event
Freudian slip? 🙂
ggm
Camburn
I may be guilty of spreading miss-information for many other matters. but for this one you have to blame the NASA
There is strong evidence of electromagnetic processes responsible for earthquake triggering, that we study extensively. We will focus here on one correlation between power in solar wind compressional fluctuations and power in magnetospheric pulsations and ground H component fluctuations.
Geophysical Research Abstracts,Vol.8,01705, 2006;Lab for Solar and Space Physics, NASA Goddard Space Flight Center,Greenbelt, MD http://www.cosis.net/abstracts/EGU06/01705/EGU06-J-01705.pdf
I’ve read before that the little ice age coincided with a period where there were very little sunspots and that when the sunspots returned, it got warmer. As such, I don’t buy this study at all. I think they are looking to science to dismiss any solar connection for the past warm and cool periods and this is one such example.
And I thought the hockey stick got rid of the LIA?
I am sceptical as to the amount of cooling caused by volcanic eruptions, but I do not dispute that they are in principle capable of emitting copious amounts of aerosol particulates which are capable of blocking solar irradiance.
Look at the Best data for 1800 to 1825. See http://www.woodfortrees.org/plot/best-upper/from:1800/to:1825/plot/none
Can one really see the effects of Tambora (1815) and/or much smaller Galunggung (1822) eruptions.
dave38 says:
January 30, 2012 at 3:00 pm
//////////////////////////////////////////////
I think the river flow was different back then and that this assisted the freezing.
I am not sure whether the river was narrower, or whether it was partly blocked as you say or whether it was more silted up or less tributaries connected with it. No doubt there could be a variety of reasons behind the differences in flow rate..
thingadonta:
Solar radiation does NOT vary much from cycle to cycle. The light composition within the TSI does.
Mount Fuji, the highest in Japan (3776 m), also erupted in 1707 and caused harvest failure and famine.
OK, how much lead and lag did this volcano induced climate change display?
What happens if they incorporate the history of volcano activity as an input to the climate models? Does the purported sensitivity to CO2 go up or down?
It is not enough to come up with an alternate explanation for LIA, it has to be used to improve model accuracy.
Brent Hargreaves says:
January 30, 2012 at 2:57 pm
///////////////////////////////////////////////
Brent
I am with you on this as you will note from my post of 3:50pm.
For example looking at the BEST data set for 1860 to 1890:
http://www.woodfortrees.org/plot/best-upper/from:1860/to:1890
Can one really see Krakatoa (1883) in this data given the natural variabiitly that appears to be in that set?
As a sceptic, I question the effects of volcanos. I can certainly accept the principle but I do feel that volcanic eruptions can be over-hyped by the warmist to overcome inconvenient data.
During the depths of the Little Ice Age;
http://www.eh-resources.org/timeline/timeline_lia.html
http://en.wikipedia.org/wiki/Little_Ice_Age
there were more major volcanoes. i.e. ones with a Volcanic Explosivity Index (VEI) rated 5 or higher;
1580 ± 20 – VEI6 – Billy Mitchell
1586 – VEI5? – Kelut, Java
1593 – VEI5? – Raung, Java
1600 – VEI6 – Huaynaputina
1625 – VEI5 – Katla
1640 – VEI5 – Komaga-Take, Japan
1641 – VEI6 – Mount Parker
1650 – VEI6 – Kolumbo, Santorini
1660 – VEI6 – Long Island (Papua New Guinea)
1663 – VEI5 – Usu, Japan
1667 – VEI5 – Shikotsu (Tarumai), Japan
1673 – VEI5? – Gamkonora, Halmahera
1680 – VEI5? – Tongkoko, Sulaw
as compared to a period such as our prior century:
1902 – VEI6(?) – Santa Maria, Guatemala
1907 – VEI5 – Ksudach, Kamchatka
1912 – VEI6 – Novarupta (Katmai)
1932 – VEI5+ – Azul, Cerro (Quizapu)
1956 – VEI5 – Bezymianny, Kamchatchka
1980 – VEI5 – St Helens, US
1982 – VEI5 – El Chichon, Mexico
1991 – VEI6 – Pinatubo, Philippines
The effects of volcanoes on Earth’s climate are well know, e.g. “the 1991 explosion of Mount Pinatubo, a stratovolcano in the Philippines, cooled global temperatures for about 2–3 years.
In 1883, the explosion of Krakatoa (Krakatau) created volcanic winter-like conditions. The next four years after the explosion were unusually cold, and the winter of 1887 to 1888 included powerful blizzards.Record snowfalls were recorded worldwide.
The 1815 eruption of Mount Tambora, a stratovolcano in Indonesia, occasioned mid-summer frosts in New York State and June snowfalls in New England and Newfoundland and Labrador in what came to be known as the “Year Without a Summer” of 1816.
A paper written by Benjamin Franklin in 1783 blamed the unusually cool summer of 1783 on volcanic dust coming from Iceland, where the eruption of Laki volcano had released enormous amounts of sulfur dioxide, resulting in the death of much of the island’s livestock and a catastrophic famine which killed a quarter of the population. Temperatures in the northern hemisphere dropped by about 1 °C in the year following the Laki eruption.
In 1600, the Huaynaputina in Peru erupted. Tree ring studies show that 1601 was cold. Russia had its worst famine in 1601 to 1603. From 1600 to 1602, Switzerland, Latvia and Estonia had exceptionally cold winters. The wine harvest was late in 1601 in France, and in Peru and Germany wine production collapsed. Peach trees bloomed late in China, and Lake Suwa in Japan froze early.[4]
In 1452 or 1453, a cataclysmic eruption of the submarine volcano Kuwae caused worldwide disruptions.
The Great Famine of 1315–1317 in Europe may have been precipitated by a volcanic event,[5] perhaps that of Kaharoa, New Zealand, which lasted about five years.[6]
The extreme weather events of 535–536 are most likely linked to a volcanic eruption.”
http://en.wikipedia.org/wiki/Volcanic_winter
If there is a potential climatic catastrophe we should be prepared for, a major volcanic eruption seems like a good candidate…
I have been investigating the link to solar flares – there appears to NO link whatsoever.
Many proponents of solar warming pull ad hoc hypothesis out of the hat. This has been the strategy of Scafetta and West over the years, and we have no illusion that our paper will actually put them to silence. However, the only scientifically valid strategy to confront these new hypotheses is to shoot down every new missile as they come in, using the most advanced weapons at hand. We believe that this operation was successfully accomplished with respect to the complexity linking hypothesis, but there will be many more battles to be fought until the issue of the contribution of solar variability to recent global warming is settled.”
More information: M. Rypdal and K. Rypdal. “Testing Hypotheses about Sun-Climate Complexity Linking.” Physical Review Letters 104, 128501 (2010). DOI:10.1103/PhysRevLett.104.128501
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My Opinion:
This link to solar and its random effects can only be settled if we take yet another 15 year slab of the evidence from 2012 to 2027. If this period continues to warm above and beyond negative forcing inclusive of those who are unable to accept the core science of AGW many theories are going fall – and very hard.
I have it on good good knowledge and advice that (cmae fro0m one of them at a hEartland Conference) two scientists who are mildest will support the AGW hypothesis ( according to IPPC estimates) of an upper 2 degree Celsius by the end of this century if temperatures continue to rise over this period.
I also understand if those estimates are correct then global action will turn to addressing all these issues and the debate between non-warmest and warmest will be all over.
Nicola Scafetta says:
January 30, 2012 at 3:33 pm
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I stumbled across that research from Heidelberg University a couple of weeks ago,
http://img.photobucket.com/albums/v207/neuralnetwriter/GlobalWarming/JK_Austrian_Speleothem.jpg
http://www.uibk.ac.at/geologie/pdf/spa12.pdf
and I was very surpirsed, that such precise reconstructions of the last millenium exist, that they are NOT local (same results, same peaks from spaleothemes in Northern Europe, North Atlantic, China, Chile,…) and that they are so well correlated with the sun’s output.
Actually, many questions in climate science have been answered with that – but nobody cares…
The way this page renders on my browser the phrase “computer simulations conducted for the study” appears under the picture of the person picking at the rocks.
Are you sure that this is not the correct caption for the photo?
If we take this a step further, would that mean there is the potential for really low activity cycles, like 24 and 25 are projected to be, to set off eruptions of super volcanos like Yellowstone?
Perhaps it was the Lake Toba eruption about 70,000 years ago that began the last ice age.
http://en.wikipedia.org/wiki/Lake_Toba
I understand the authors used a constant for solar output. Fine, my question is different:
Has anyone validated the TSI measurements? I understand they claim .01% accuracy over the entire range using one instrument. At solar max when EUV is many times higher than usual, is this extra energy content really included in TSI accurately? Are other bands giving lower energy at that time to balance (or the EUV band too narrow to matter)? Perhaps measurements of many energy bands from other satellites could be used to check? I just don’t understand how a many-times increase in EUV can have so little overall effect…
Isn’t the cause of the solar cycle and its variations, the gravitational effects between the sun and planets ?
If the suns output can change as a result of gravity why can’t the earth’s behavior with respect to volcanoes and earthquakes ?
As I understand things, solar activity is the result of “tides” within the Sun,
Why can’t the earth have similar “tides” in the mantle ?
I should certainly think minor effects on the mantle could have significant consequences in terms of volcanoes and earthquakes.
“The study, which used analyses of patterns of dead vegetation, ice and sediment core data, and powerful computer climate models”… LOL
Tropical volcanoes? Which ones? As if such surge in activity would only affect tropical volcanoes not others… If so, ash deposits would be easily found and dated. their mapping would indicate the extent of activity but that would mean real research… not running a model. Next time a volcanologist will be interested in monitoring the activity of some volcano, he’ll check dead vegetation in the Arctic and run a model… LOL
Hey, wait a minute…’The model, which simulated various sea ice conditions from about 1150 to 1700 A.D., showed several large, closely spaced eruptions could have cooled the Northern Hemisphere enough to trigger the expansion of Arctic sea ice.’.
If one looks up major volcanic eruptions, there are not several large, closely spaced eruptions during the period they indicate. One 1258, one 1280, one 1310….Those are not closely spaced.
The text (so far, the study is ‘in press’) does not show that they actually identified and verified any such set of eruptions, only periods of sudden cold (dead plants, thicker ice layers).
I will hold my breath until the study is available….I want to see if they can show evidence of the blamed ‘several large, closely spaced eruptions’.
@ur momisugly rossbrisbane says: January 30, 2012 at 4:07 pm and M. Rypdal and K. Rypdal’s paper.
The paper by Rypdal and Rypdal criticizing one of my 2003 papers has been properly rebutted
N. Scafetta and B. J. West, “Comment on `Testing hypotheses about Sun-climate complexity linking’ ” Phys. Rev. Lett. 10.1103/PhysRevLett.105.219801 (2010).
http://www.fel.duke.edu/~scafetta/pdf/PRL2010-e219801.pdf
Rypdal and Rypdal simply took apples for oranges.
@ur momisuglyManfred says: January 30, 2012 at 4:11 pm
Actually, many questions in climate science have been answered with that – but nobody cares…
Right now it is very difficult for good papers to get a visibility in the politicited media news!
In any case, there are exceptions!
http://www.forbes.com/sites/larrybell/2012/01/10/global-warming-no-natural-predictable-climate-change/
Just The Facts
“During the depths of the Little Ice Age…there were more major volcanoes. i.e. ones with a Volcanic Explosivity Index (VEI) rated 5 or higher;..”
Thanks for that. I have been trying ti get up the motivation of wading into the GVP site and digging that out.
My gut feel is that the astronomical connection to plate tectonics and volcanoes is a load of carp… but that large volcanic events during a low in solar activity is the “two push” event that triggers the really cold events.
Billy Liar says:
January 30, 2012 at 3:43 pm
Yep……saw it after it was posted but no way to correct.
Robert Brown says:
January 30, 2012 at 12:04 pm
One of the things I wonder about is that during low sunspot activity, does the reduced solar-magnetic influence have any effect on Earth’s plate tectoncs and vulcanism? Does a reduced solar-magnetic influence prompt more volcanism?
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An interesting question. From an energy point of view, it doesn’t seem likely — I’ve estimated the power associated with magnetic induction and although it is a very large number, it is a very small number compared to the size the Earth. Of course, I could have made a mistake in my arithmetic, but I wouldn’t think that the forces are large compared to, say, tidal forces.
rgb
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@ur momisugly Robert Brown and whoever he was responding to
I believe there is a strong possibility that the tetonic plates have a direct influence on the magnetic fields of any solar induced magnetic flux.
Several years age I was playing around with a compass (needle type). Don’t even ask why I was doing this. By placing it on the body of my car, as I moved it across the hood it remained fairly accurate. As it was moved to the edge of the hood the needle changed considerably. Interesting. I tried it on the trunk, fender, and every sheet metal object available. Same effect. I don’t remember the orientation of the needle but I think it may have aligned with the edge of the metal. If there is some valid reason for this, then the possibility exists that the plate tetonics could very well effect the magnetic field at the intersection, or break if you will. Just my observations. The geomagnetic forces on the Earth generated by the sun are possibly much greater than we can imagine and may be the ‘rabbit in the hat’.