Previously Unknown Volcanic Eruption Helped Trigger Cold Decade

From the University of California, San Diego Press Release

Photo of Mt. Pinatubo

The previously unknown eruption in 1809 was larger than the Mt. Pinatubo eruption. Credit: USGS

A team of chemists from the U.S. and France has found compelling evidence of a previously undocumented large volcanic eruption that occurred exactly 200 years ago, in 1809.

The discovery, published online this week in the scientific journal Geophysical Research Letters, offers an explanation as to why the decade from 1810 to 1819 is regarded by scientists as the coldest on record for the past 500 years.

“We’ve never seen any evidence of this eruption in Greenland that corresponds to a simultaneous explosion recorded in Antarctica before in the glacial record,” said Mark Thiemens, Dean of the Division of Physical Sciences at UC San Diego and one of the co-authors of the study. “But if you look at the size of the signal we found in the ice cores, it had to be huge. It was bigger than the 1991 eruption of Mount Pinatubo in the Philippines, which killed hundreds of people and affected climate around the world.”

Photo of Jihong Cole-Dai
Jihong Cole-Dai of South Dakota State U. headed the research team. Credit: South Dakota State U.

Led by a chemist from South Dakota State University, the team of scientists made its discovery after analyzing chemicals in ice samples from Antarctica and Greenland in the Arctic, where the scientists visited and drilled ice cores three years ago. The year-by-year accumulation of snow in the polar ice sheets records what is going on in the atmosphere.

“We found large amount of volcanic sulfuric acid in the snow layers of 1809 and 1810 in both Greenland and Antarctica,” said professor Jihong Cole-Dai of SDSU’s Department of Chemistry and Biochemistry, who was the lead author of the paper.

Joël Savarino of the Laboratoire de Glaciologie et Géophysique de l’Environment in Grenoble, France, and a former postdoctoral fellow at UC San Diego, was also part of the team.

Cole-Dai said climate records show that not only were 1816 — the so-called “year without a summer”— and the following years very cold, the entire decade from 1810 to 1819 was probably the coldest for at least the past 500 years.

Photo of
The team drilled ice cores in Greenland’s ice sheet. Credit: Mark Thiemens, UCSD

Scientists have long been aware that the massive and violent eruption in 1815 of an Indonesian volcano called Tambora, which killed more than 88,000 people in Indonesia, had caused the worldwide cold weather in 1816 and after. Volcanic eruptions have a cooling effect on the planet because they release sulfur gases into the atmosphere that form sulfuric acid aerosols that block sunlight. But the cold temperatures in the early part of the decade, before that eruption, suggest Tambora alone could not have caused the climatic changes of the decade.

“Our new evidence is that the volcanic sulfuric acid came down at the opposite poles at precisely the same time, and this means that the sulfate is from a single  large eruption of a volcano in 1809,” Cole-Dai said. “The Tambora eruption and the undocumented 1809 eruption are together responsible for the unusually cold decade.”

Cole-Dai said the Tambora eruption was immense, sending about 100 million tons of sulfur gas into the atmosphere, but the ice core samples suggests the 1809 eruption was also very large — perhaps half the size of Tambora — and would also have cooled the earth for a few years. The researchers reason that, because the sulfuric acid is found in the ice from both polar regions, the eruption probably occurred in the tropics, as Tambora did, where wind patterns could carry volcanic material to the entire world, including both poles.

Photo of
UCSD’s Mark Thiemens (upper left) pulls a cylinder in Greenland containing an ice core. Credit: UCSD

Cole-Dai said the research specifically looked for and found a special indicator of sulfuric acid produced from the volcanic sulfur gas in the stratosphere.

The special indicator is an unusual make-up of sulfur isotopes in the volcanic sulfuric acid. Isotopes are different types of atoms of the same chemical element, each having a different number of neutrons (but the same number of protons). The unique sulfur isotope composition is like a fingerprint of volcanic material that has reached the stratosphere, said Cole-Dai.

The stratosphere is the second major layer of the Earth’s atmosphere, reaching from about six miles to about 30 miles above the Earth’s surface at moderate latitudes. To impact global climate, rather than local weather, the sulfur gas of a volcanic eruption has to reach up into the stratosphere and once there, be spread around the globe.

“The way in which that these volcanoes affected the average temperatures of our planet gives us a better idea of how particulates in the atmosphere can affect our climate,” said Thiemens. “People talk about the possibility of geo-engineering our climate, but the question is how? In this case, nature has done an experiment for us.”

Other members of the research team were South Dakota State post-doctoral researcher David Ferris and graduate student Alyson Lanciki; and Mélanie Baroni of CEREGE (Le Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement) at L’Université Paul Cézanne in Aix-en-Provence, France.

The researchers were funded by the National Science Foundation, French Polar Institute (IPEV) and the Institut National des Sciences del’Univers (INSU).

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Bruce

And yet … my suspicious mind suggests that now that the hockey stick is discredited somebody thought it was important to discredit the Dalton Minimum somehow …
I know … lets find a new volcanic reuption!

Gene Nemetz

…and would also have cooled the earth for a few years.
Another possible cold time the earth recovered from and that recovery unaccounted for in warming from then until today.

spangled drongo

With two of those bungers going off in the middle of a couple of solar minimums it was lucky the Napoleonic Wars were on to save us from another ice age.
No wonder Mr Dalton was cold. A pity it has such an effect on the AGW graph.
And helps to manufacture hockey sticks.

noaaprogrammer

I’ve got it: Volcanoes cause short term global cooling while at the same time causing global warming due to increasing the amount of gases accumulating in the earth’s atmosphere (recall Boyle’s Law from chemistry?) higher pressure = higher temps! Now, all we have to do is figure out how to stop all of those firecrackers from going off. Any suggestions? (We need to divert and keep the warmists busy in some area other than cap & trade.)

Hank

The article isn’t quite explicit on this point. Is this an eruption for which they have found evidence for in ice cores but haven’t yet pinpointed on the globe?

Philip_B

As I noted yesterday, the current decade is the first in modern times to have no major volcanic eruptions, which is likely ‘artificially’ warming it relative to previous decades.

Norm/Calgary

Shouldn’t this then raise the starting point of GW and thereby reduce the delta from 1820 to 2009?

Assuming that volcanoes have such an impact, it makes the current discussions about “geoengineering” seem even more insane.
Let’s see, we can’t control volcanoes, we can’t control solar output, we can’t control cosmic energy or clouds, so let’s go and try to geoengineer a cooler planet by injecting “stuff” into the upper atmosphere on purpose! Like we really know with absolute certainty exactly how it all fits together.
Insane!

savethesharks

Which volcano erupted in 1809? Was it in Antarctica? Was trying to decipher in this article…
Chris
Norfolk, VA, USA

Jeff B.

“People talk about the possibility of geo-engineering our climate, but the question is how? In this case, nature has done an experiment for us.”
Let’s hope some Alarmist nut doesn’t get the idea to create some massive man made sulphuric release in response to AGW fears that then causes even further cooling. Cold is the danger.

gtrip

When and will this ever end? Is this what life without war is all about?…. If so, give me war; At least war is real.

We have seen this kind of hype again and again [“never before seen”, “unprecedented”, etc]
This story is old hat:
Title: Ice core evidence for an explosive tropical volcanic eruption 6
years preceding Tambora
Authors: Dai, Jihong; Mosley-Thompson, Ellen; Thompson, Lonnie G.
Publication: Journal of Geophysical Research (ISSN 0148-0227), vol.
96, Sept. 20, 1991, p. 17,361-17,366. (JGR Homepage)
Abstract
High-resolution analyses of ice cores from Antarctica and Greenland
reveal an explosive volcanic eruption in the tropics in A.D. 1809
which is not reflected in the historical record. A comparison in the
same ice cores of the sulfate flux from the A.D. 1809 eruption to that
from the Tambora eruption (A.D. 1815) indicates a near-equatorial
location and a magnitude roughly half that of Tambora. Thus this event
should be considered comparable to other eruptions producing large
volumes of sulfur-rich gases such as Coseguina, Krakatau, Agung, and
El Chichon. The increase in the atmospheric concentration of sulfuric
acid may have contributed to the Northern Hemisphere cooling observed
in the early nineteenth century and may account partially for the
decline in surface temperatures which preceded the eruption of Tambora
in A.D. 1815.
Title: Two major volcanic cooling episodes derived from global marine
air temperature, AD 1807-1827
Authors: Chenoweth, Michael
Publication: Geophysical Research Letters, Volume 28, Issue 15, p.
2963-2966 (GeoRL Homepage), 2001
DOI: 10.1029/2000GL012648
Abstract
A new data set of global marine air temperature data for the years
1807-1827 is used to show the impact of volcanic eruptions in ~1809
(unlocated) and 1815 (Tambora, Indonesia). Both eruptions produced
cooling exceeding that after Krakatoa, Indonesia (1883) and Pinatubo,
Philippines (1991). The ~1809 eruption is dated to March-June 1808
based on a sudden cooling in Malaysian temperature data and maximum
cooling of marine air temperature in 1809. Two large-scale calibrated
proxy temperature records, one from tree-ring-density data, the other
using multi-proxy sources are compared to the marine air temperature
data. Correlation is highest with maximum latewood density data and
lowest with the multi-proxy data.
—-
but nice to have confirmation….

The large eruption of Mayon http://en.wikipedia.org/wiki/Mayon_Volcano in 1814 probably added to the effect.

Konrad

I am surprised they can distinguish the signal of the hypothetical 1809 volcano from the known 1816 eruption. I didn’t know ice core resolution was that fine, especially for sulfur dioxide, which could migrate in water ice. If it were volcanic ash detected in a core I could understand the proposal.

crosspatch

Such a volcano could be almost anywhere. For example Nyiragongo was not discovered by westerners until the late 19th century. To my mind, Nyiragongo represents what might be our best bet for the next supervolcano. It is fed by a mantle plume from deep down inside Earth. Lava from that volcano appears to be almost completely mantle material with very little crustal melt included. The neighboring shield volcano (I cant remember the name off the top of my head) seems to be at the edge of the plume and contains both mantle and crust melt.
There was an eruption in Saudi Arabia at Jabal Yar at about that time, too, but I don’t believe it would have been large enough. And who knows what was going on in Ethiopia at around that time. My guess is that any volcano near water would have been reported as shipping was pretty much covering the earth at that time. A continental volcano either in Africa, Alaska or someplace like far Eastern Siberia might have gone unnoticed.
I doubt an eruption in Indonesia would have gone unnoticed as that area was one of the most heavily traveled sea routes of the time.
Wish they could find some ash. That would help to locate the eruption.

Where was the volcano? The article says “The researchers reason that, because the sulfuric acid is found in the ice from both polar regions, the eruption probably occurred in the tropics, as Tambora did, where wind patterns could carry volcanic material to the entire world, including both poles.”
Where could it have been? If it were in Indonesia or Soufrierre, there should be records of it. I wonder if it could have been an underwater eruption that still allowed the release of hot SO2 into the atmosphere.
I’ll have to update my 1816 page to mention this. I have read other comments claiming there were several eruptions around that time frame, I don’t recall if I have details handy.
Volcanoes don’t impact climate for very long, 1817 was much warmer than 1816, so I’m a bit skeptical that volcanoes alone can be responsible for that cold decade.
BTW, I think the region that was most frozen in 1816 was due to the storm track following a significantly more southern route. Areas of the US like Virginia had temperatures much closer to normal. Don’t assume the impact in places like New England and Europe were similar to the rest of the world.
—-
Proveit count: 880 in, 5851 out. From the steady small gains each hour,
there’s no blatant ballot box stuffing going on.

crosspatch
crosspatch

Also confirmation from back in 2002:

While global cooling followed the
eruption, climate had already begun to cool before 1815.
Ice core records from Greenland and Antarctica preserve
sulfuric acid layers from volcanic eruptions, and while all
records at both poles show a Tambora layer, they also all
show a layer from an eruption almost as large in 1808
or 1809, still unidentified
. Thus, the climate was probably
already cooling from a previous large eruption and several
smaller ones also observed between the two large ones. If
Tambora had erupted in a warmer climate, the effects would
have been less harsh. While this is true in an absolute sense,
in a relative sense they would have been larger and more
easily attributable to the volcano

So this information does not seem to be anything new.

crosspatch

Also an eruption in 1808 of Taal (VEI2 explosive eruption)
So maybe it wasn’t one eruption, maybe it was several large eruptions at about the same time.

gtrip

“A team of chemists from the U.S. and France has found compelling evidence of a previously undocumented large volcanic eruption that occurred exactly 200 years ago, in 1809.”
Puke….puke again……..

We did not know?
What else is there that we do not know?
It is the presumption of the vain and foolish to believe that knowledge has ended with them.

maksimovich

Ric Werme (22:50:19) :
: Volcanoes don’t impact climate for very long, 1817 was much warmer than 1816, so I’m a bit skeptical that volcanoes alone can be responsible for that cold decade.
There is also a possibility that there are centennial implications eg Stenchikov et al 2009
Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.
http://www.agu.org/pubs/crossref/2009/2008JD011673.shtml

Leif Svalgaard (22:38:06) : “We have seen this kind of hype again and again …This story is old hat:”
Litmus test…

Jason

It is the proposition of the arrogant to drastically change a planet-important value of the world they live on. Argon doesn’t have a cycle. Why don’t you go play with that instead?

Jason

Rule # 1 Don’t play with elements that have cycles. C, O, N, P, H2O (though not an element).. All determining the existance or nonexistance of life.
If we start altering these values too much in any significant subset where they are important such as air, ocean, land etc. we’re in for some trouble.. Be glad a few of these are impossible to change and the shallow(ing) curve of +temp/+ppm helps us out.

Philip_B (22:15:07) : You wrote, “As I noted yesterday, the current decade is the first in modern times to have no major volcanic eruptions, which is likely ‘artificially’ warming it relative to previous decades.”
How are you defining modern times? There were also no major explosive volcanic eruptions from the 1920s through the 1950s.

Refer to the Lamb Dust Veil Index. There were also a number of explosive volcanic eruptions during the period, though none as large as Tambora.
http://cdiac.ornl.gov/ftp/ndp013/ndp013.dat

Sandy

Meteorological principles should still apply when the heat source is geo-thermal rather than insolation.
The eruption column from Tambora was 28 miles high (RN frigate).
Before height of mountain 13,000ft after 9,000ft.
25 miles away the water rose to 12ft above normal high tide.
Some of that 12ft will be wind driven storm surge, but a good amount must also be lowered atmospheric pressure.
Why? Well 25 miles away I think we had a hyper-tornado. Something so far beyond a Kansas twister that superlatives run out.
The amount of hot gases rose not explosively but thermodynamically picking up inrushing air. The sheer heat didn’t notice the inversion at the stratosphere that caps Cu-Nims and when straight on up getting practically all the way out of the atmosphere. But there was no orbital velocity so all the gases and particulates fell back over the atmosphere like an onion skin, leading to no summer the following year. Had that volcanic dreck not been squirted straight through the atmosphere the biological devastation would have covered thousands of miles. Gaia??
Looking at the crater on google earth it seems now to be very symmetrically round as though it was counter-sunk. To be ground down from 13,000ft to 9,000ft means that some house-size+ chunks of harder lava rock must have been blown about smashing the lava-ash layer structure of the shield volcano. Indeed I’m sure impacts should still be visible today since minerals change under the intense pressure/heat of a few tons at silly speeds.
So guesses as to the pressure and wind-speeds this monster peaked at?
I offer 300mb central pressure and 1000mph + wind speeds.

Back2Bat

When and will this ever end? gtrip
Believe it or not, our banking model is at fault. AGW is seen as a convenient lie to put the brakes on a form of malignant economic growth that is destroying the environment among its many other sins. It is driving people mad.
Our current model, government backed fractional reserve banking in a government backed monopoly money is based on looting purchasing power (theft) stealthily via inflation and interest rate suppression. It is the culprit behind the boom/bust cycle. See Mises, Rothbard and the Austrian school of economics for details.
AGW is doomed, IMO, but the hydra will just sprout another head if we don’t fix the root cause.
War is not the answer.

Leon Brozyna

The previously unknown … previously undocumented … never seen any evidence of this eruption before in the glacial record … our new evidence …
How embarrassing it must be for them to learn that what they’ve done is not discover something new, but to have replicated a study reported on 18 years previously. And what kind of researchers are they that they appear to be unaware of a similar study of an unlocated 1809 eruption reported on 8 years prior, in the very peer-reviewed journal in which their report appears? Are researchers so driven by the need for funding that they must report on their work as being new rather than independant replication? Just look at how quickly Dr. Svalgaard was able to find those two earlier studies. But then, while replication may serve to confirm the validity of earlier studies, it’s just not as sexy and exciting as reporting on something as a new discovery.

tallbloke

noaaprogrammer (22:09:23) :
Now, all we have to do is figure out how to stop all of those firecrackers from going off. Any suggestions? (We need to divert and keep the warmists busy in some area other than cap & trade.)

Form a chain gang of all the warmists to carry rocks up the volcanos and bung up the craters. We could pay them in carbon credits to do it. A new policy of trade and cap.

Completely off topic (which just offers more support to the lack of solar influence)…….but have readers since this.
http://www.sciencemuseum.org.uk/proveit.aspx
There is a Poll which doesn’t appear to be going terribly well for the copenhagen crowd (i.e. currently around 6 to 1 against action) . If you are still able to vote; the ‘Out’ option (against) is the RH option, the ‘In’ option (For) is to the left. Apparently the results of the poll will be passed onto the UK government.
Apologies if this has already been mentioned.

Tony Hansen

Bob Tisdale (01:09:23) : ‘There were also no major explosive volcanic eruptions…’ How major is major?
The VEI numbers seem to bounce around a bit depending on who I read. How much use do you think the older (pre satellite, pre aircraft) VEI figures are?
There also seems to be some suggestion of a degree of subjectivity in the DVI figures. Is this true, and if so, how much of a problem might it be?
Do you know of an up-to-date DVI? Everything I have been able to find is rather old.
Regards

Grumbler

“gtrip (22:33:38) :
When and will this ever end? Is this what life without war is all about?…. If so, give me war; At least war is real.”
I agree. Very profound. The threat of war would do the job as well.
‘War – what is it good for’ – giving preople a focus and a purpose.
cheers David

Mr. Alex

OT but check it out :
http://www.earthfiles.com/news.php?ID=1635&category=Science
A very interesting new interview with David Hathaway about the deep solar minimum, record cosmic rays and comments on his failed 2006 prediction…an excellent read.

Patrick Davis

My word! Some “event”, previously, “happened”, caused “something big”. I mean, if it is not modelled in a cumputer, nor on YouTube, does it happen?

Don S.

Google “1809 volcano”, get 116,000 hits in under a second. They must not have been able to spare a second from writing the grant application.

Don S.

It appears that the lead investigator here was also associated with a 1991 study of the same subject.

Pofarmer

So, supposedly tsi only changes by one percent.
What is the equivalent change caused by a volcanic eruption?

Tenuc

There does seem to be a link between geological disturbance and the solar cycle. I wonder if changes to magnetic fields have an effect the Earth’s crust?

Tom

It’s very odd. I tried to find the paper so I could see whether the authors cited the earlier studies (meaning that the press release was overhyped but the authors were responsible) but I can’t find it on line. The AGU has nothing published in any of their journals by the named authors. Possibly SDSU jumped the gun and the study will not be published until next week. Does anyone have the actual citation?

Back2Bat

Grumbler (03:36:37) :
‘War – what is it good for’ – giving preople a focus and a purpose.
Visit a Veteran’s Hospital sometimes is my suggestion. I haven’t the stomach for it but then I don’t advocate for war.
But OTOH, it is good to see that people realize we have a serious problem even if the proffered solutions are deranged.
The banking model is based on government-backed systematic violation of
“Thou shall not steal”, “Thou shall not bear false witness”, commands to use honest weights and measures and commands to not oppress the poor. This is the root of our problems.

P Gosselin

Arctic temps are cooling now. (From Germany).
http://klimakatastrophe.wordpress.com/2009/10/30/die-arktis-zeigt-seit-2005-eine-tendenz-zur-abkuhlung/
Translation:
THE ARCTIC SHOWS COOLING TREND SINCE 2005
Hard to believe, but it looks like the Arctic has been cooling since 2005 (since about 5 years). One has to wonder because the Arctic is touted as the indicator of global climate change. Precisely here are temperatures supposed to be rising rapidly due to manmade climate change. But now the opposite seems to be occurring.
The temperature of the north polar region as measured by satellites (above: UAH & RSS) show a drop since 2005.
This is confirmed by global surface temperature measurements (below, NASA-GISS).
The north polar region has been cooling since 2005, as the comparison of 2005 to the subsequent 2006-2008 show. A cooling is also measured globally for this period.
This shows the short term development of the last 5 years.
How will the trend develop in the future?

Tom in Florida

Mr. Alex (03:39:25) :
“OT but check it out : http://www.earthfiles.com/news.php?ID=1635&category=Science
A very interesting new interview with David Hathaway about the deep solar minimum, record cosmic rays and comments on his failed 2006 prediction…an excellent read.”
In this interview David Hathaway says:”But there also were people back at that time saying otherwise. A group of colleagues led by Leif Svalgaard, Ph.D., were looking at the sun’s polar fields and saying even at that point, the sun’s polar fields were significantly weaker than they had been before and those scientists back then predicted it was going to be a small cycle.”
He also freely admits he and others were wrong and are now moving on with Dr Svalgarrd’s position.
This is how science should be. No “I told you so”, no gloating of who was right and who was wrong. No illogical defense of a defenseless position, no personal attacks, no blame, no excuses. Just a simple admission that what was thought at the time didn’t occur. If only the IPCC had such integrity.

Jimbo

Leon Brozyna (02:42:30) :
The previously unknown … previously undocumented … never seen any evidence of this eruption before in the glacial record … our new evidence …
Also on the press release they say “The discovery….” instead of the re-discovery:-)
The South Dakota State post-doctoral researcher David Ferris and others just didn’t do their research did they? Visiting Greenland and Antarctica 3 years ago to ‘dicover’ what was already discovered and waisting money, resources and adding to the toxic Co2 gas in the atmosphere. Maybe their university is desperate for some public cash.

pyromancer76

Shame on Mark Thiemens, Dean, Div of Phys Sci, UC San Diego. Shame on UC San Diego; Shame on Jihong Cole-Dai, Dept Chem, South Dakota State College; Shame on the Dept of Chemistry there. Leif called them out immediately. Where is the disciplinary process when researchers don’t report the findings that went before their own? Where is the responsibility of scientists (all researchers) to their fields? Where is the humility and respect of all that went before and the pride in truly NEW findings. It’s like slaying fathers over and over again. Narcissism will destroy the scientific method — and representative democracy.
My real concern is volcanoes and “climate change”. Anthony keeps the subject before us. Maunder Minimum — Little Ice Age — mid-1600s. From Robock: Volcanic Eruptions and Climate (Reviews of Geophysics 38,2 – sorry, I lost the date): …”The radiative forcing from volcanoes are interannual rather than interdecadal in scale. A series of volcanic eruptions could, however, raise the mean optical depth significantly over a longer period and thereby give rise to a decadal-scale cooling”. I don’t know the reputation of the scientist in his field, but he continues with “…Volcanic forcing explained a much larger share of the temperature variability since 1620 than did the solar series. He points to studies in the 1970s, Schneider and Mass [1975] and Robock [1979]. Unfortunately he has gone over to the dark (AGW) side, but my spotty research finds significant volcanic activity in the mid-1600s.
Examples: 1. Mt. Etna, Italy, periods of voluminous eruptions 1607-1669 (Tanguy ea 2007 Bull. Volcanology). Most of the 17th c eruptions, almost annually, have a VEI of 2 until 1669 when VEI 3 occurs (Billi and Funiciello 2008 A. Geophysics).
2. Komaga-take, Japan, 1640 eruption, one of largest in Japan during historical time. There was another in 1644. (volcano.si.edu).
3. A chart of bristlecone pine tree rings (shudder, tremble) and volcanic eruptions over the last 5000 years that finds ring-width minima in two or more regions (~2yrs) and corresponding ice-core volcanic signals within 10 yr of minima shows the following significant dates:
1602
1606
1618
1641
1644/45/56
1675/77
1681
(Salzer and Hughes 2007 Quaternary Res 67)
4. Measuring carbonyl sulfide (COS-a long-lived sulfur gas of which volcanoes contribute 10%) from SPRESSO ice core East Anarctica (if honest, scientifically valid measurements) show a spike beginning in 1600 and increasing toward the end of the century. “A longer period of high volcanic activity occurs around 1600-1700 CE. This coincides with the height of the LIA and elevated COS levels. (p. 7537)” (Aydin ea 2008 Atmos Chem Phys 8:7533)
5. Lucia on The Blackboard has shown that large swings in GMST are related to volcanic eruptions from ~1890 to 2000. (9/17/08) Her other arguments don’t seem important here.
The main point is that when a number of powerful enough volcanoes erupt in a narrow time frame, the “natural” cooling they add (I think I read that 25 volcanoes are emitting something everyday ) might coincide with other important factors that bring about cooling. Something interesting with volcanoes has happened at both the Maunder and Dalton minima. Is there any connection?

Greylar

Konrad (22:41:01) :
I am surprised they can distinguish the signal of the hypothetical 1809 volcano from the known 1816 eruption. I didn’t know ice core resolution was that fine, especially for sulfur dioxide, which could migrate in water ice. If it were volcanic ash detected in a core I could understand the proposal.

Oh yea, in fact the CIA is using it to spy on peoples eating habits which affect gaseous emissions into the atmosphere and ultimately polar ice.

I mean, if it is not modelled in a cumputer, nor on YouTube, does it happen?
If a husband says something in the forest and his wife is not around to hear it, is he still wrong?

Fred2

I love reading this stuff, you realize that man is but energetic little pimple on the hind end of an geological elephant.
Something like the Deccan or Siberian traps, massive asteriods, etc… could happen and we’d all be dead or back inthe stone age (about the same thing, really for all but an unlucky few) faster than you could say “what was that loud noise?”

Curiousgeorge

@ Grumbler (03:36:37) :
“gtrip (22:33:38) :
When and will this ever end? Is this what life without war is all about?…. If so, give me war; At least war is real.”
I agree. Very profound. The threat of war would do the job as well.
‘War – what is it good for’ – giving preople a focus and a purpose.
cheers David”
Without conflict this would be a barren planet. I have little patience with those who claim that war never solved anything.