Guest Post by Willis Eschenbach
Once again, Anthony has highlighted a paper claiming that volcanoes have great power over the global temperature. Indeed, they go so far as to say:
From the reconstruction it can be seen that large eruptions, such as Mount Tambora in 1815, or clusters of eruptions, may result in a hiatus of over 20 years, a finding supported by model results.
SOURCE: Determining the likelihood of pauses and surges in global warming, Andrew P. Schurer et al, hereinafter Schurer2015, paywalled here.
Here we go again, sez I, another excuse for the current temperature plateau … and right out of the box, I note that we are dealing with a “reconstruction”, with findings that are “verified by model results”. Be still, my beating heart …
So I thought I’d give their claim a looksee by comparing their recent (post-1800) eruption dates with the Berkeley Earth land temperature record. You know, first see what the observations have to say.
I’m using a variant of the method that they use in the paper, which is to “stack” the temperature records, aligning them at the year of the eruption. I have used the years since 1800 that they have identified in the ice cores as being the years of the big injections of sulfates into the stratosphere from volcanic eruptions. These include inter alia the eruptions of Pinatubo (1991), El Chichon (1982), Mt. Agung (1963), the big eruption of Krakatoa (1883), and the largest eruption during the period, Tambora (1815). Tambora was the volcano responsible for a few areas having a “Year Without A Summer” in 1816. Here are all of the years of big stratospheric eruptions:
Figure 1. Table S3 from Schurer2015.
Now, “Crowley and Untermann” is reconstruction of historical stratospheric eruptions based on sulfate levels in ice cores in Greenland and Antarctica. After a bit of searching I found the data here. Figure 2 shows their best estimate from the data of the tropical AOD, based on the ice core sulfates.
Figure 2. Aerosol Optical Depth (AOD), a measure of the amount of stratospheric aerosols, based on ice core records of the sulfate levels. The dotted horizontal line was the accept/reject line for consideration in Schurer2015. One hemisphere had to be above an AOD of 0.1 to be considered for the paper.
Now, in this graph we can see how much more sulfate aerosols were ejected into the stratosphere by Tambora in 1815 than by any other volcano in the last two centuries.
So I’ve taken those years shown by the dotted lines, and I’ve “stacked’ them in Figure 3, showing the span from five years before to five years after each eruption. In the background of Figure 3 are all of the 11-year spans in the dataset, shown in gray. This indicates the expected variation of the data. Over that, I’ve shown the nine eruptions used for this period in Schurer2015.
Figure 3. Stacked eruptions, aligned on the eruption date at Year 0. In gray in the background are all possible 11-year spans from 1800 to 2014.
There are several things of interest. First, as I’ve discussed before, even the mighty eruption of Tambora doesn’t change the global temperature much if at all. Globally the “Year Without A Summer” is the “Year Without A Difference”. Yes, I understand that in some locations the summer was cooler. But it seems the anecdotes have far outpaced the reality. In Missing The Missing Summer I showed eight datasets which cover the time period. None of them shows an unusual summer in 1816. And in Figure 3 you can see that according to the Berkeley Earth data, globally the “missing summer” of Tambora is scarcely a blip.
More to the point, the average of the stack shows that in general there’s no significant effect from the volcanoes. Nor is there any “dose-related” effect. Tambora, with the largest AOD, doesn’t have a significant temperature drop after the eruption. On the other hand, the largest post-eruption drop is from the eruption with the smallest AOD, that of 1903.
I know that this is difficult to accept after years of hearing how volcanoes strongly affect the climate, but here’s what I say is happening. When the stratospheric aerosols cut down the sun slightly, the tropical surface cools slightly. Because the tropical surface is cooler, the cumulus clouds form later in the day, allowing in more sun. So the weaker sun is compensated for by the longer time that it is striking the surface, and as a result there is very little change in the global average temperature.
In this manner, despite even the size of the 1815 Tambora eruption, and despite the fact that local areas showed cooling after Tambora, the stratospheric aerosols from this huge eruption had little effect on the global average temperature. More stratospheric aerosols are simply balanced out by less tropospheric clouds, and the beat goes on.
Conclusions? Well, my main conclusion is that Schurer2015 way overstates the effect of volcanoes on the global surface air temperature. For them to have a 20-year effect is very doubtful, particularly given the short lifespan of the stratospheric aerosols, as shown in Figure 2. In no case do they remain airborne for more than six years or so. How could their effect last another fourteen years?
In fact, as Figure 3 shows, on average there is no global effect at all visible in the first five years.
So I’ll say, as I’ve said before, that while volcanoes can certainly affect local areas, rumors of the power of volcanoes to affect global average temperatures have been greatly exaggerated.
Best to all,
w.
A Strong Request: If you disagree with something that has been said, please quote the exact words you disagree with. That lets us all be clear about a) the person you are addressing, and b) just what they said that you object to.
Further Reading: As I mentioned above, I’ve written extensively on how little the eruptions affect the temperature. Here is a list of my previous posts on the subject:
Today I thought I’d discuss my research into what is put forward as one of the key pieces of evidence that GCMs (global climate models) are able to accurately reproduce the climate. This is the claim that the GCMs are able to reproduce the effects of volcanoes on the climate.…
Prediction is hard, especially of the future.
[UPDATE]: I have added a discussion of the size of the model error at the end of this post. Over at Judith Curry’s climate blog, the NASA climate scientist Dr. Andrew Lacis has been providing some comments. He was asked: Please provide 5- 10 recent ‘proof points’ which you would…
The claim is often made that volcanoes support the theory that forcing rules temperature. The aerosols from the eruptions are injected into the stratosphere. This reflects additional sunlight, and cuts the amount of sunshine that strikes the surface. As a result of this reduction in forcing, the biggest volcanic eruptions…
Dronning Maud Meets the Little Ice Age
I have to learn to keep my blood pressure down … this new paper, “Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks“, hereinafter M2012, has me shaking my head. It has gotten favorable reports in the scientific blogs … I don’t see it at…
Since I was a kid I’ve been reading stories about “The Year Without A Summer”. This was the summer of 1816, one year after the great eruption of the Tambora volcano in Indonesia. The Tambora eruption, in April of 1815, was so huge it could be heard from 2,600 km…
New Data, Old Claims About Volcanoes
Richard Muller and the good folks over at the Berkeley Earth Surface Temperature (BEST) project have released their temperature analysis back to 1750, and are making their usual unsupportable claims. I don’t mean his risible statements that the temperature changes are due to CO2 because the curves look alike—that joke has…
BEST, Volcanoes and Climate Sensitivity
I’ve argued in a variety of posts that the usual canonical estimate of climate sensitivity, which is 3°C of warming for a doubling of CO2, is an order of magnitude too large. Today, at the urging of Steven Mosher in a thread on Lucia Liljegren’s excellent blog “The Blackboard”, I’ve…
Back in 2010, I wrote a post called “Prediction is hard, especially of the future“. It turned out to be the first of a series of posts that I ended up writing on the inability of climate models to successfully replicate the effects of volcanoes. It was an investigation occasioned…
Volcanoes: Active, Inactive, and Retroactive
Anthony put up a post titled “Why the new Otto et al climate sensitivity paper is important – it’s a sea change for some IPCC authors” The paper in question is “Energy budget constraints on climate response” (free registration required), supplementary online information (SOI) here, by Otto et alia, sixteen…
Stacked Volcanoes Falsify Models
Well, this has been a circuitous journey. I started out to research volcanoes. First I got distracted by the question of model sensitivity, as I described in Model Climate Sensitivity Calculated Directly From Model Results. Then I was diverted by the question of smoothing of the Otto data, as I reported…
The Eruption Over the IPCC AR5
In the leaked version of the upcoming United Nations Intergovernmental Panel on Climate Change (UN IPCC) Fifth Assessment Report (AR5) Chapter 1, we find the following claims regarding volcanoes. The forcing from stratospheric volcanic aerosols can have a large impact on the climate for some years after volcanic eruptions. Several…
I see that Susan Solomon and her climate police have rounded up the usual suspects, which in this case are volcanic eruptions, in their desperation to explain the so-called “pause” in global warming that’s stretching towards two decades now. Their problem is that for a long while the climate alarmists…
Eruptions and Ocean Heat Content
I was out trolling for science the other day at the AGW Observer site. It’s a great place, they list lots and lots of science including the good, the bad, and the ugly, like for example all the references from the UN IPCC AR5. The beauty part is that the…
Well, we haven’t had a game of “Spot The Volcano” in a while, so I thought I’d take a look at what is likely the earliest volcanic eruption for which we have actual temperature records. This was the eruption of the Icelandic volcano Laki in June of 1783. It is claimed to…
[also, see update at the end of the post] Anthony recently highlighted a couple of new papers claiming to explain the current plateau in global warming. This time, it’s volcanoes, but the claim this time is that it’s not the big volcanoes. It’s the small volcanoes. The studies both seem to…
Enjoy.
UPDATE: I don’t think Willis will mind if I include this excellent graph prepared by Joe D’Aleo of Weatherbell:
As you can see in the bottom panel, the aerosol loading during “the pause” is close to zero. So much for Schurer2015 and their claims – Anthony
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Once again I have been given an opportunity to state that, built into the idea that CO2=warming, is that the lower stratosphere will cool, while the lower troposphere will warm. So again then: The lower stratosphere has NOT cooled since 1995. I’ll say it again. The lower stratosphere has NOT cooled since 1995. It did cool, which enforced the CO2 hypothesis, but it stopped cooling in 1995…and even shows a very slight warming. Will someone please put me out of my misery by explaining to me why a big deal is NOT being made of this?
http://s11.postimg.org/lxwzon2rn/Volcanoes_and_Lower_Strat_Temps_1978_2014.png
The stratosphere is the clue to understanding the real, long term effects of volcanoes?
Discussed in detail here:
https://climategrog.wordpress.com/?attachment_id=902
An old plot that needs updating. How the heck you get a sufficient grasp on ozone depletion and recovery to look at this I have no idea. Every dataset I look at since Montreal came along is a nightmare.
Great chart. Your trendline from 1995 to the end of the graph has a slope that is too steep. One way to visualize this as being obvious is to see that it starts closer to the lows and ends much closer to the highs. There are numerous ways to draw trendlines though, so I’m not sure what this one is based on.
If it is meant to represent the mid point of some average along the way, look at it this way.
Starting from 1995 to the end…….. during the first ~50% of the trendline, there is close to an equal amount of data points below and above the trendline. This is good. However, after this, during the last ~50% of the trendline, almost all the data points/ “area” are below the trendline. This can mean several things.
1. There was a trend change at around the halfway(50%) time frame from a steeper uptrending slope to less steep slope………in fact, you can make a case for it to be flat or even a slight downtrend after ~50% into the period of the slope you’ve drawn.
2. Since you are using just 1 line to represent the entire period, then clearly, that one line should be placed so that data points are more equally distributed on both sides of the trend line.
3. It looks like you took the trendline from the first half of the period and extended it into the 2nd half of the period, when the trend had changed.
4. This trendline being discussed starts closer to the lows and ends closer to the highs is another way to view it as not fairly representing what the trend of the data is telling us……..unless your definition is different than what I’ve described.
The previous comment was directed at the chart/graph of The Ghost Of Big Jim Cooley showing the Lower Stratosphere and Volcanoes, Time vs Temp Anomaly. I realize that it was probably drawn by the source that he used.
Thanks Mike, but not my graph:
http://wattsupwiththat.com/2014/08/04/what-stratospheric-hotspot/
Spot on Big Jim!
Well, you live and learn. Thanks Jim.
I don’t understand your objection. More CO_2 simply raises the height where the atmosphere becomes transparent to CO_2 based thermal emissions. Since the atmosphere lapses, this reduces the average intensity of outgoing radiation in the CO_2 band. Since the total input energy from the sun MUST be balanced in dynamic equilibrium (on average) by the sum of radiation emitted or reflected directly from the Earth’s surface (all sources) and the radiation emitted or reflected from the atmosphere (all sources) if you drop the intensity of one of the sources, the others must increase to compensate and maintain detailed balance. Nearly all of the ways this can happen involve at least some additional warming.
I don’t see anything in this that requires the stratosphere or troposphere to change temperature — much. One expects surface temperature to increase a bit as one raises the mean emission height. This will raise the temperature of everything coupled to the surface, a bit, as well. But the key is raising the emission height.
rgb
The emission height does not increase in the saturated bands. Adding molecules merely LOWERS the altitude and raises the lapse temperature of complete absorption. Above this altitude CO2 molecules see no outgoing photons. This was extensively measured in the ’60’s from radiometer equipped aircraft.
This may speak somewhat to the difference between surface and TLT temperatures.
rgb:
The stratosphere cooling is a known effect from anthropogenic global warming, or at least it would be. This has been discussed many times in the past on realclimate, but also right here on WUWT. Indeed, in the paper discussed on the link below, it is said, “[stratospheric cooling] is a more suitable signal of anthropogenic global warming”.
http://wattsupwiththat.com/2014/08/04/what-stratospheric-hotspot/
As the lower troposphere warms, the stratosphere should cool. Indeed, I’m surprised that no one like Dr Roy Spencer hasn’t jumped on the fact that stratospheric cooling isn’t happening as PROOF that UAH and RSS data on TLTs are correct.
More CO2 has a number of associated feedbacks including atmospheric water vapor changes which we are reasonably sure will happen but can’t predetermine. You cant simplify the net effect that like that. It might be true but stating it as fact simply doesn’t follow and is counterproductive to overall understanding.
TimTheToolMan: “More CO2 has a number of associated feedbacks including atmospheric water vapor changes which we are reasonably sure will happen”
There is no evidence whatsoever from the NASA NVAP data to back that statement WRT water vapour.
Here are three analyses:
Vonder Haar
http://onlinelibrary.wiley.com/doi/10.1029/2012GL052094/full
Humlum
http://www.climate4you.com/GreenhouseGasses.htm
Solomon et al.
Abstract
Stratospheric water vapor concentrations decreased by about 10% after the year 2000. Here we show that this acted to slow the rate of increase in global surface temperature over 2000–2009 by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases. More limited data suggest that stratospheric water vapor probably increased between 1980 and 2000, which would have enhanced the decadal rate of surface warming during the 1990s by about 30% as compared to estimates neglecting this change. These findings show that stratospheric water vapor is an important driver of decadal global surface climate change.
So, rather the opposite, it seems.
@Catweazle. I specifically said “changes” and didn’t give a direction so I’m not sure where your “rather the opposite” comment comes from.
I agree that there is a problem with the AGW theory because a drying of the stratosphere will counteract any additional CO2 above the ERL and so tend to have the effect of decreasing the ERL which is opposite to rgbatduke’s assumption. The net result? Nobody knows.
rgbatduke:
I don’t, either, but I think that’s beside the point. I think The Ghost of Big Jim Cooley is saying that temperatures’ falling in the stratosphere and rising in the troposphere is a consequence of the positive-feedback theories, not of the “greenhouse” effect per se, which is what Dr. Brown was referring to.
I’ve seen that said often, so I’m guessing it’s true, but I haven’t seen causal connection between positive feedback and temperature spread explained. Perhaps The Ghost of Big Jim Cooley or another reader could elucidate.
Oops; I had a brain cramp; sorry for injecting confusion.
Yes, the theory behind the changing temperature spread does indeed seem to be based on the “greenhouse” effect per se, just not on the aspect that Dr. Brown described.
I can’t say I understand it, but it appears to be something about the increased optical density’s causing different gradients. The plausibility argument seems to be that the greater concentration causes more upward as well as downward radiation so that, once you’ve passed the effective radiation altitude (for a given wavelength) the carbon dioxide is more effective at cooling if there’s more of it.
Or something like that.
So volcanoes’ are mere eruptions,
On the broad face of the world.
… much more sulfate aerosols were ejected into the stratosphere by Tambora in 1915 than by any other volcano
Make it 1815 and delete this comment.
: > )
Thanks, Juan, fixed. I don’t delete the comments of folks who assist me, why would I?
Appreciated,
w.
“When the stratospheric aerosols cut down the sun slightly, the tropical surface cools slightly.” This reminds me of a PID controller. The big question is just what sets the “set point”. The drifting increase in temps over the past three centuries is like “reset wind-up” on a P controller that lacks an Integral effect.
The next question is that if climate is self regulating controller, what sends it haywire as ice ages hit and what corrects it?
2014 was the warmest year in the world. Undipustable fact. And 2015 will be warmer.
Can you clarify?
It is obvious. The media of the left said so.
John, you’re a pointless troll. 97% of years in the last 10,000 were warmer than 2014. Get a life. R.
There we go with that “97%” thing again….
Maybe. Maybe not.
So what? You are completely off-topic.
> Undipustable fact
You don’t understand anything concerning natural science.
There is no undisputable fact.
Thank you for taking the discourse to such an elite level. The spelling is quite creative, too.
Indeed …the only undisputable fact is that John is challenged when spelling undisputable 😉
Too funny!!
Just imagine if there were no spell check. The spelling would be the worst evah!
John,
You say … “Undipustable” fact !
Please state WHICH world you are on: it would help to know … oh wait … no, I think I saw you last night; just behind that galaxy which is obscured by our moon … yes … perhaps you are the “stratospheric aerosol” everyone’s so eager to meet.
That explains it: no need for you to reply here (unless of course you are a qualified railway engineer).
Do drop in and give us all a thermal emission whenever your next orbit is close.
Thanks awfully.
Dear undisputable John,
Through time, and continues changing of the past, they (the alarmist) will reach their “warmest ever” objective, all the while ignoring that both satellite data sets, calibrated to the most accurate thermometers , immune to UHI, changing stations, homogenization, scarcity of measurements, etc., show that 1998 was the warmest by a factor about 1,000 PERCENT larger then the “warmest year ever” nonsense they manufacture.
They will ignore that the satellite demonstrate that 1998 was considerably, easily and statistically significantly warmer then 2010, 2014 and 2015. They will ignore that the troposphere was supposed to warm FASTER then the surface. They will ignore the increase in global sea ice now enhanced by increasing ice in the NH. They will ignore the flat and very minor sea level trend. They will ignore that even their manufactured warming is far below the IPCC computer model mean on which the predicted harms of CAGW are based. They will ignore the slight increase in NH snow. They will ignore record ice on the great lakes. They will ignore that all the harms of CAGW are failing to manifest, while the benefits, saving massive amounts of fresh water and massive acreage of land are feeding close to one billion people every year.
============================(That is a lot of ignoring)================================
instead they will manufacture a tiny bit of warming, encourage “warmest year ever” nonsense headlines all over the world, while crying doom for humanity, all they while padding their wallets and take home pay while shamelessly preventing real problems from being addressed.
=================================(That is evil=====================================
All you people criticizing John are a bit out of line.
John did not specify which world.
Aw, com’on. Now that’s piling on!
Eugene WR Gallun
Model World; Model World; Party Time.
Somewhere in the multiverse (which I don’t believe in) there’s a planet doing exactly what the models say.
Taz1999
Even in the multiverse there is no planet that can simultaneously lie in so many ways as do the multitude of worthless models that produce their pointless, disagreeing and unphysical predictions of apocalypse.
My son would say “Harsh much?” Sure made me smile
“the multitude of worthless models that produce their pointless, disagreeing and unphysical predictions of apocalypse”
That quote and the models/real data graphs ought to go on billboards 🙂
I stated that at the start of 2015 that no matter what the reality nor data , 2015 would be the ‘warmest year ‘ [because] of the ‘Paris affect ‘ , so it is no surprise to find out that is what is being claimed has it could never have been any other way.
Mile high glaciers could have been seen rolling over the white house and the claim would still have gone up that 2015 was the ‘warmest year ‘
Please insert the following warning when derailing the discussion:
“2014 was the warmest year in the world.”
Since the creation? Which world are you talking about? (Or is this some wonderfully subtle reference to post-Kripke metaphysics?)
“And 2015 will be warmer.”
Same world? (It’s certainly not the one I live in.)
Rubbish.
Stop making stuff up.
John, are you giving us a money-back guarantee that none of the temperature data for 2014 will ever change in the future? Today’s temperatures cannot be considered reliable if they are going to be “corrected” at anytime in the future. The data we have for the years before 2014 have been adjusted, some many times. What makes 2014 so special that its data would be carved in stone and immune from future adjustments?
BTW, what is an “undipustable fact” I don’t see what having pustables in your undies has to do with facts.
Willis –
The obvious question which comes to mind given your data and explanation regarding tropical ocean cloud feedback is: what was the effect over land areas? Those areas will see the cooling without the compensating heating your postulate.
Also, I know history is not science, and I’m not even a historian, but it is hard to believe that the stories
crops failing and snow & frost in June (was that New England?) could have no basis in reality at all….
R.
Today we have freak rainstorms, hot days in winter, snow storms in summer, floods and drought. In each and every case somebody always points the finger at CO2 and ignores the fact that freak weather has always occurred.
The past was no different. If a crop failed or there was freak weather it is inevitable that people would point the finger at the eruption.
If you had followed Willis’ link to the “Missing the Missing Summer” story you would have found a graph from The Price History of English Agriculture, 1209-1914 which shows that food prices were at their lowest in the years after the eruption which wouldn’t be the case if there was widespread crop failures.
You might argue that England is a small place and doesn’t necessarily represent the whole world, which is fair enough, but if you do want to claim that there was widespread crop failure then find the data (eg rising prices due to scarcity) and point to it.
Food prices dropped in Britain because of the end of the Napoleonic Wars.
Sturgis
Sure.
But the series referred to starts more than 500 years before the well-known Bonaparte was actually born.
And, if I may:
Willis has highlighted the effects – if any – of eruptions in the last 200-250 years.
There have been bigger ones.
What effect would ‘they’ have today – say a Yellowstone event?
Never-mind an Indian Deccan fields . . . . . . .
Do I know? No.
Auto
I was referring to prices in Britain in the year after Tambora, to explain why they didn’t rise there. On the continent, there was famine, particularly in landlocked areas like Switzerland, as a result of Tambora. Likewise China.
A Tambora today would be bad for agriculture. The world has the ability now to aid regions suffering famine, but a global, or at least NH, crop failure would be calamitous. A Yellowstone? Fugedaboudit!
Happy I’m upwind (usually) from Yellowstone while being too far inland to suffer greatly from the Juan de Fuca Big One. Maybe a sweet spot, geodisaster-wise.
Who cares, other than you?
About 71 percent of the Earth’s surface is water-covered, and the oceans hold about 96.5 percent of all Earth’s water.
And the 29% that is land covered, I’ll make a guess and say that 25% of said land is not located in the equatorial zone where the majority of “heating” occurs.
And the winds push/carry that tropical “heat” toward the poles.
It isn’t the event being disputed it is the cause of that poor summer that seems to be in doubt. We often join dots and impute relationships that on deeper investigation aren’t there. Willis’ article seems to do that.
RERT, to give an explanation, probably there were localized cold areas, especially inland, and I would not be surprised if there were several days of noticable haze across large sections of the globe. However, as a whole, the effect disappears into annual varibility.
Now, if I can give a guess, over time, this black cloud of haze blocking the sun was magnified into legend. Any negative effects were attributed to this cloud (see how in some rural areas they point to pollution causing birth defects despite the pollution being smaller than typical city pollution), while positives were ignored, amplifying the damage of the volcano through the power of selective perception.
Willis,
In scientific literature there is extensive debate about the 1809 “mystery” or “unknown” volcanic eruption, which in strength is believed to be second only to Tambora for eruptions in the last couple of hundred years. Ice cores indicate that there has been a massive eruption in 1809 as well, but no one seems to know where it took place.
I don’t see any discussion of this eruption in your post, but you must be aware of it, as it was posted previously at WUWT and you commented in the threads.
So, is it relevant?
There have been some suggestion that the eruption took place in South America – at the time a sparsely populated region with few people documenting things.
A paper on this eruption can be found here, see references in the paper for more on this.
http://www.clim-past.net/10/1707/2014/cp-10-1707-2014.pdf
Indeed, even the Smithsonian records it as “Unknown Source”. My own feeling is that it may be dust from the Tunguska Event, but who knows?
w.
But the Tunguska event was in 1908.
If you note, the 1809 eruption is graphed on the big spaghetti-plot, though not referenced directly in the text. It doesn’t seem to be important temperature-wise, as it occurred during a cooling trend and didn’t have a strongly discernable effect.
Dirty glasses again?
http://climexp.knmi.nl/data/it2m_land_best_1800:1820_13month_low-pass_loess1a.png
Okay the huge drop in temperature occured in 1809.
From where did the nature know that 6 years later – in 1815 – the Tambora will explode?
Crystal ball?
There was a large eruption in 1809 also, and temperature had not recovered in 1815.
The WfT graph shows that drop in 1809:
http://woodfortrees.org/plot/best/from:1800/to:1820
Okay, maybe an effect of the mysterious eruption. But in 1810 the temperature anomaly recovered to values suitable to the trend from 1801 to 1808.
No drop in 1815.
http://virakkraft.com/BEST-aerosols.png
Igl, the problem was that the temperature was dropping from a peak in 1805 including steep drops in 1807 and 1808, and 1809 corresponds to the end of the drop. Unless you are claiming the entire record was corrupted to show the effect before the cause, the eruption of 1809 cannot be assigned to that temperature drop.
benofhouston
Willis have used the same silly argument before. Nobody has ever claimed the temperature graph would have been a straight line without the volcanoes. There are lots of natural oscillations like ENSO, AO, PDO.
lgl July 22, 2015 at 1:16 pm
So how about you act like a man, lgl, and you gather all of your courage, and actually quote the “silly argument” that you are discussing? I get so tired of this kind of mudslinging and vague accusations. PLEASE EITHER QUOTE MY WORDS, OR TAKE YOUR UNPLEASANT WHINING ELSEWHERE!!
Sheesh … why is this so hard?
w.
Willis Eschenbach: “Sheesh … why is this so hard?”
Debating trolls is like wrestling with a pig, Willis.
You get muddy, and the pig enjoys it.
The best thing to do with trolls is to occasionally poke them with a sharp stick, but on no account to feed them.
Willis
http://wattsupwiththat.com/2015/01/09/volcanoes-once-again-again/#comment-1832734
@lgl
For the large eruption in 1809, WHY did the temperature start dropping in 1808?
ENSO perhaps.
.One noticeable effect in Willis’ fig 3 is that the range of temps on the after eruption side is about half that on the pre-eruption side. That suggests a net calming effect on temperature change ( warmer winters, cooler summers ) .
There is also a drop in overall level, though much of this drop occurs BEFORE the eruptions, indicating a concurrent change that is being falsely attributed to the volcanic effects.
What is noticeable about Tambora is the strong RISE about 3y after the eruption. This is true for both the 1809 and 1815 eruptions.
This is also seen after El Chichon and Mt Pinatubo, though that is a bit lost behind the large lines used in Willis’ graph.
Where this all leads is that the post eruptions cooling of TLS and surface warming has been totally ignore by climate science so far and that the reason for the “hiatus” has more to do with the LACK of volcanoes that caused the late 20th c. warm burst that had everyone getting into hysterics.
To suggest that the piffling amount of activity since 2000 has caused or even contributed to ” the pause ” shows just how desperate they are about reviving this particularly dead horse.
It’s as absurd as to suggest that global warming has caused modern slavery. 😉
http://www.theguardian.com/environment/2015/jul/21/pope-links-climate-change-with-human-trafficking-and-urges-un-to-take-lead
Little else is needed, but I will add the measured atmospheric clarity chart from WUWT’s solar page – to again display just how little the actual volcanic effect has been measured since the pause began in 1996-1997 time frame.
http://www.esrl.noaa.gov/gmd/webdata/grad/mloapt/mlo_transmission.gif
While it’s pretty clear that global temps are not significantly affected by volcanoes, the “year without a summer” seems to be historically fairly well established. Has anyone done a land-only comparison of the 30-60N band only? That’s going to geographically cover most of the sources of the “year without a summer” stories.
Wrong Willis. Volcanoes have a big effect on climate, the higher the ejecta the greater the effect. If you mean by “local” you mean on a hemispherical basis then I would agree but not otherwise.
Active volcanoes are mainly fairly above or below the equator. There is little mixing in the atmosphere north/south so effects remain that “local”.
Ejecta includes ,
Ash, can increase albedo so reduce radiation input.
SO2. Will reduce radiation input.
CO2, Will lower temperatures.
So a definite measurable temperature drop.
Yes. But after one year the ejecta will have left the atmosphere for the most part.
Willis described a mechanism which counteracts the reduced input of solar energy. So the temperature drop may be reduced a lot.
Willis qualified his analysis to after 1800. Please note that this is necessary when speaking of volcanic eruptions. https://en.m.wikipedia.org/wiki/Volcanic_explosivity_index. The vei of Yellostone has recently been found to be even greater than indicated in this citation. One of these goes off, game over.
It would seem to me that almost all of the active volcanoes on earth are either north or south of the equator.
John Marshall July 22, 2015 at 5:15 am
First, despite my request, you have not quoted my words. So when you say “Wrong Willis” nobody knows what you think I did wrong.
Second, posts like yours are known in the trade by a technical term … they’re called “handwaving”. You make all kinds of claims, but you don’t adduce a single fact, graph, citation, study, or any other support for your position. Instead, you just make a bunch of claims and wave your hands, and we’re supposed to believe you.
Fail. Sorry to be so blunt, but your comment is a classic fail.
However, it’s no big deal, because you are welcome to come back with a quote of whatever you think is wrong, and some kind of facts to support your point.
w.
It seems that the graph added by AW from Joe D’Aleo shows that the large volcanic eruptions counteract any El Nino and/or would contribute to a longer La Nina.
Only one major problem with Willis’ methodology. What if major volcanic eruptions are a symptom of extended cooling periods. This would mean that each large volcanic eruption in the tropics (or cluster of eruptions) would be preceded by an extended period of global cooling.(say five, ten or even fifteen years).
What Willis should do is normalize his curves in figure 3 to temperatures five (ten or even fifteen) years prior to the eruption rather than the time of eruption.
Just a friendly suggestion.
I consulted my tarot card reader: you are right!
Good point Ian, the cause-and-effect relationships have certainly not been empirically established in any of the interactions which govern this whole geo-climatic environment thing.
No way.
To take this seriously, you would have to propose some mechanism where minute changes in global temperature would have significant effects on geologic changes. Sorry, but that beggars belief. If cold was an instigator of vulcanism, then the tropics would be volcanically silent and most eruptions would occur in winter.
You don’t need just correlation. You need a plausible cause that doesn’t introduce severe disparities with reality.
benofhouston,
What if there were external factors that could lead to cold periods on the Earth (e.g. reduced solar activity associated with global cooling) that could also affect the Earth’s rotation rate (by increasing or decreasing the length-of-day). Under these circumstances you might expect to see a reduction in world temperatures that would also be accompanied by increased stresses on the Earth’s crust.
I think that if you look at Willis’ figure 3 very carefully you will see that if he normalizes the curves associated with the volcanic eruptions to a epoch five years prior to the eruption you will see a systematic cooling of the volcanic curves compared to those for randomly selected 10 year periods.
Change in rotatation? That would affect temperature and volcanos., but we would certainly have noticed such a change if it happened since the invention of the chronometer, and very likely millenia before that, so that is completely irrelevant to that discussion.
Solar activity. Yes it would affect temperature, but I would need some evidence that it affects geological effects. This reduces to my prior post. If this was the case, you would see a large annual swing in volcanos that just doesn’t exist.
All proposals I have heard for the temperature->Volcanoes would have much more significant and quite noticeable effects.
And trying what you say by eyeball, it doesn’t align well at all. You just get an inverted version of figure 3, with a ludicrously wide swath of changes going at year zero. There is a vague downward trend, but it is nowhere near universal, especially if you take the spaghetti splot from the greyed out background into account.
With no plausible mechanism you need some intriguing supporting data.
Benofhouston, Hopefully this will help you understand my point.
The following two statements are independent of each other:
Reduced solar activity —- leads to — reduced the world mean temperature.
Reduced solar activity —- leads to — small changes in the Earth’s rotation — producing stress on crust.
The reduction in the world mean temperatures has little or no connection to the increased stress on the Earth’s crust.
Eventually the stresses in the crust build up and they are dissipated in increased volcanic activity.
Hence, your argument that vulcanism would vary through the seasonal temperature cycle is totally spurious.
And, if you are so sure about figure 3, why not get Willis to re-plot it with the normalization taking place at 5 years prior to the date of eruptions. When I do it by eye, I see a clear negative trends in temperature in the epochs surround large tropical eruptions compared to randomly selected 10 year epochs.
Ian, I understand you perfectly. However, I’m rejecting your premise. Any influences on the earth’s crust significant enough to cause vulcanism would be readily measurable and have large influences that we could easily see.
You can’t just say “the sun causes small stresses”. You need a viable mechanism where solar radiation would trigger changes in the geology. As the majority of solar radiation is absorbed in the atmosphere or directly onto the surface, the best guess of a vector is temperature, which reduces back to our first argument. You could also argue changes in the magnetic field, but that has been well monitored for a century for people looking specifically for a connection to earthquakes and volcanoes. If the effect was significant, we would have seen it by now.
As it is, your statement is a magic handwave. Magic handwaves actually have their place in science, but they can only be used when saying “we have no idea about the cause”. Ie: Newton’s statements on the cause of gravity. You cannot use it to say “it was the sun but we don’t know how” unless you can make a clear and unambiguous correlation that has predictive power.
And if you are so sure about figure 3, then YOU plot it. Don’t waste my time, much less Willis’s, demanding that we do the work for you. It’s your theory, provide some evidence that I can take seriously.
Not sure about centering on yearly averages. The mysterious 1809 eruption allegedly happened in December 1808, so the ‘following’ year is technically 1809. Tambora happened in April, so you how valid is it to compare the temperature in Jan-Dec 1815 (i.e. including 8 months after the eruption) with the temperature Jan-Dec 1816 (8-20 months after the eruption)?
Second question: how much stratospheric mixing occurs between hemispheres and how fast? Can anyone enlighten?
Willis,
Terrific paper, it is nice to get a sailor’s perspective on any climate issue. Am I way off by thinking that volcanoes are like temporary large urban heat islands with stratospheric self buffering?
Extrapolating a bit here, but if there is little lasting effect from successive ‘large’ volcanic eruptions such as those in 1809 and Tambora, potentially using Willis’s regulator, is it possible that end ‘Permian’ volcanism is also overplayed as a cause of this major earth life crisis (and yes I am well aware of the other ’causes’ like impacts etc, and also aware that the extinctions started earlier in the Late Permian).
Ciao
John
john gorter. I’m a little suspicious of the “extinction events” notion of evolutionary change. You know, the wayward asteroid! The notion seems to be a plausible explanation for the disappearance of “dominate” species but really never accounts for those that survive and seem to have no special trait that should have saved them (Crocodiles, turtles, sturgeon, sharks, lizards in the case of the asteroid). Not sure if the evolution of life is driven by catastrophe.
It looks to me like Tambora only had an effect for about 5 months in 1816. It seems their imagination is strong if they feel they can justify a 20 year effect.
I extracted the data for the 42 stations in the ISTI database which have full records 1801-1830. There are another 100 or so which have broken records during the period over half having less than ten years of data. Using just the 42 stations no mystical adjustments are necessary for latitude, elevation or missing data.
Here are a couple graphs of those stations.
1801-1830 annual mean temperature.
http://oi60.tinypic.com/34hf0oo.jpg
1801-1830 May-Sep mean temperatures.
http://oi59.tinypic.com/30ixnwy.jpg
Thanks, Bob, quite interesting. My problem with such graphs is always that if I didn’t know when the volcano occurred, I wouldn’t be able to pick it out. For example, in your second graph, the largest year-to-year drop is post 1811, second largest is post 1804, third largest in 1819 … and that is hardly a finger of guilt for Tambora in 1816.
w.
Willis, your posts are excellent, but n this one you appear to be century challenged.
Grrr … thanks, David. Fixed.
w.
Bob, that puts a marked drop in temperature just prior to the multiple earthquakes and sand blows along the New Madrid fault in 1811-12. Fascinating that this was during the Dalton minimum.
Hi Willis,
Thanks in particular for the link to optical depth data — I wasn’t aware of this source. I’ll use it to redo (independently) my own computation of a “best fit” response function for the temperature using HadCRUT4. Berkeley seems surprisingly different, off the top of my head, especially after El Chichon, where there was strong cooling, lagged by an inexplicable two years. It’s also amusing to see that the temperature “knew” Pinatubo was going to erupt, because it dropped even more before it erupted than it did afterwards. Artifacts like this are common in the volcano vs temprature fit — when I tried this before, there were plenty of eruptions with almost no effect, eruptions where temperature went the wrong way — basically as you show above (but don’t point out sufficiently strongly) — the natural variation on the left is as big or bigger than the supposed response on the right. One cannot really resolve the effect of volcanoes from the natural year to year variation of the temperature record — one barely improves a fit by adding a volcano model to a CO_2 only model as I showed in the last thread, and one can easily get a much bigger improvement with a 0.1 amplitude sinusoid that has no explanation that I know of.
One thing I’m excited by is the opportunity to refit using OAD directly. I inferred it using VEI and ejecta volume and a simple model built using Mauna Loa data, but the latter only covers a few large eruptions and eruption VEI is not a very good proxy for aerosol load. I didn’t realize that ice core data captures the actual optical aerosol load and that this work had been done, so using the data itself (with a presumably better/different proxy if nothing else) will both let me check my own model and will let me better map response to supposed atmospheric transparency.
But I’m pretty certain of what I will find, as it agrees quite well with what you find. Volcanoes have almost no resolvable effect on climate. Big ones, little ones, lots of volcanoes or a few. I’m not even going to model “volcanoes” in my next effort — I’m just going to add NH/SH AOD averaged as a model parameter with some sort of linear/exponential response function (probably a lagged adjustable exponential kernel so that impulses have a year to make themselves felt and then have a model-fit exponential decay effect, but also so that the background gets to contribute and modulate the CO_2 fit). I expect that this will very slightly improve the quality of a CO_2 only fit. I won’t even guess as to whether it will increase or decrease climate sensitivity.
It is remarkable that a paper is being trumpeted publicly even before it is actually published that is so obviously, and seriously, flawed. Aren’t the referees familiar with the data? The hypothesized effect even if real isn’t resolved from the data — the volcano signal is buried in the natural noise — and as you note there may well be feedback mechanisms that partially cancel any cooling response.
This latter seems increasingly likely. One way of interpreting the evidence we’ve both looked at is that aerosols are pretty much irrelevant to climate. Boy, is that one a toughie. Everybody blames aerosols for cooling during the smog era, everybody wants to blame volcanoes for cooling all along the temperature record, and perhaps they do cool, locally, for a year or two, affecting the weather but not the climate. Not resolvably so.
Remove aerosols altogether from the GCMs, and they must radically change to fit the reference data. Since you cannot cancel GHG plus feedback warming against aerosol cooling, GHG plus feedback warming has to substantially decrease. Climate sensitivity plunges. The agreement of the models with the observed climate improves. But the motivation for taking drastic measures to reduce GHG emissions plunges along with the sensitivity. An unwelcome message for those that are suckling at this particular pork barrel teat.
rgb
You may be right, but I will flog my “Temperate” horse a bit more.
The Faint Sun Paradox: 800 million years ago, the sun was only 70% as bright as today, yet the climate was broadly similar. People tried desperately to invoke CO2 as the reason but it would not work. The answer had to be water vapor and clouds, which means mostly in the tropics. So you are right about that, if you can compensate for the sun like that, a volcano will not have much impact.
But it still does not address temperate zones (particularly NH) which do not have anywhere near the ability to make clouds (or not) from evaporated seawater.
This 1984 paper found a global T drop of 0.4 to 0.7 degrees C following Tambora:
http://m.sciencemag.org/content/224/4654/1191
There were crop failures and famine in Europe, North America and China.
The sun was only about seven percent weaker than now 800 Ma. The faint young sun paradox refers to the early earth, some 3800 Ma.
@ur momisugly Sturgis:
OK, Thanks. Looks like I got a bit ahead of myself there.
Still, 7% is huge compared to the 1.234 w/m2 “forcing” warmists go on about for CO2.
Sturgis Hooper July 22, 2015 at 7:04 am Edit
Sturgis, thanks for a fascinating paper. However, they place a strong caveat on their results, viz:
This is the point that I have made repeatedly—the year-to-year global change following even the largest volcanic eruptions are not significantly different from the average annual change. They cannot be identified, either visually or by any other method, in the global temperature records.
Now, were there local events? Absolutely. Consider that according to the source, there were areas within 600 miles (1,000 km) of Tambora where it was “pitch black” for two days following the eruption. Would that affect the local temperature? Dang betcha.
But globally? The earth responds immediately to changes in forcings. People imagine that the earth is a slave to the forcing. But when the tropics cool, the clouds go away, and the sun pours in to warm it up again. It is the basis of the system that has kept the temperature to within ± 0.3°C over the entire 20th century. This is astounding stability in a free-running system regulated by things as evanescent as clouds …
Finally, it is crucial to remember that this temperature regulation is occurring in an hourly/daily timeframe. There is no lag in the response of the clouds to the immediate conditions.
w.
It is about the annual variation in insolation, actually (which is roughly 91 W/m^2). The Earth’s orbit is substantially elliptical. And paradoxically, the Earth is coldest at perihelion (January, SH summer) and warmest at aphelion (July, SH winter). One of many things that I find puzzling in spite of the glib explanations I hear for it. The point is that the climate, while remarkably stable around some fixed point over geological time, hasn’t been stable around the same fixed point. It is currently at least bistable (we’re in an ice age) if not openly multistable as the modes/periods of oscillation have switched repeatedly over the Pleistocene as the periods of glaciation have lengthened and — dangerously — deepened.
Personally I don’t like to think in terms of CO_2 “forcing”, I prefer to think in terms of TOA incoming and outgoing radiation and detailed balance of ins and outs. I think that expressing things as “forcings” is one of many things that has gotten the modelers into trouble. CERES may eventually cure that problem — direct measurements of incoming vs outgoing radiation over several decades may teach us something very important. Inside the Earth-Ocean-Atmosphere system, things are very, very complex. It’s easy to make an assertion like “aerosols are very important to the climate” and have it turn out to be dead wrong, once one has enough data to prove it. And that assumption makes other assumptions wrong, and an entire computational model can fall over like a house of cards. But if one does take the forcings model seriously then yes, the variation due to CO_2 is extremely small compared to both annual variations and annual fluctuations in temperature that one presumes come from modulation of all mechanisms of gain and loss of energy in completely natural climate dynamics, some of which must function as substantial negative feedback systems in order for the system to be as stable as it is.
rgb
rgbatduke
July 22, 2015 at 8:21 pm
That is a good way of looking at it.
TonyL
The sun gets about one percent weaker for every 110 million years you look back in time. This simple linear function might not have applied early in its history, but for as recently as 800 million years ago, it would apply. For 3850 Ma, it yields an estimate of 35% fainter than now.
Your comment goes to the essence. And newer papers constrain aerosols to less than half of what CMIP5 generally assumed. Nic Lewis redid his sensitivity estimates based on the new lower aerosol range and IIRC came in about 1.5, down from 1.7 in Lewis and Curry. Cancel the climate alarm.
You don’t cut (public) money pipelines leading to pockets of well-meaning billionaires. That would be a dangerous, even subversive, activity.
Yeah, but will any of this hit the mainstream before AR6? Will there even be an AR6? Or will it just be oops, we meant to say Climate, apostrophe,
Never mind.
rgb
Exaggerated volcanic effects support the warmer’s exaggerated aerosol effects. As a result, we have imaginary zombie volcano effects.
The less effect volcanoes have, the less credibility the warmer’s overinflated direct and indirect aerosol effects have.
Very nice explanation for tropical areas (more or less clouds to compensate), which in large measure makes up the global average. But the argument does not address temperate areas at all. In my area (New England), the year without a summer really happened, and people lived through it.You do not even have to go back as far as the Civil War, so it is not ancient history. In the temperate areas, “did not happen because Tropical ….” really does not work.
I think the best intepretation of the data isn’t that the “Year Without a Summer” didn’t happen, but just that it’s effects on annual temperatures are insignificant. These are the official temperature records at the time and they don’t show a large effect. You could probably see some quite significant effects if you go on short enough time scales, but it’s just lost in the noise from a big picture when discussing global temperature records on an annual basis.
Thanks, Tony. A couple of points.
First, most of the solar energy enters through the tropics, and as a result, the regulation of incoming sunshine by tropical clouds affects the overall energy balance of the planet.
As to temperature regulation in temperate areas, there are two main ways that happens. One is indeed by the same mechanism as in the tropics, which is by the temperature dependence of the timing and amount of the emergence of thermal cumulus and cumulonimbus (thunderstorm) clouds. When it is cool we get less thermal clouds, which lets in more sun … simple but effective. This happens in the moist areas. For example, it was common in England when I was there in September. And it’s common in the monsoonal areas of the planet such as India, China, the Mississippi Valley, and the American Southwest.
Where it is too dry for that kind of regulation, the burden shifts to the humblest emergent temperature regulating phenomenon, the lowly dust-devil. As with cumulus and thunderstorms, the emergence of dust-devils is temperature driven. This means that they occur only over the hot spots, and they move huge quantities of energy skywards, cooling the surface.
Between them, these two mechanisms are a major part of the direct temperate temperature regulation.
Next, did the “year without a summer really happen”? Depends on what you mean by “really happen”. As I pointed out, there were short-lived effects in various parts of the planet … but how much, and where?
Here’s the problem. These are two ten-year periods from one of the early records covering the time, New Haven, Connecticut. Perhaps you could tell us which one is the “Year Without A Summer”, the blue arrow or the green arrow?
http://wattsupwiththat.files.wordpress.com/2012/04/new_haven_tambora-_temps_no_dates.jpg
As you can see, the actual historical records show that the stories get bigger over time. Please see my post Missing The Missing Summer for no less than seven other contemporaneous thermometer records which also show no “year without a summer”.
All the best,
w.
PS—The correct answer is that the summer indicated by the blue arrow is the “missing summer” …
I lived in Minneapolis the summer Pinatubo erupted. I remember there was really only a couple of totally sunny days that summer and the strange thing was that a lot of people’s tomatoes didn’t ripen that year. The next summer was back to normal.
We have beds of bentonite in WY that are 14 feet thick. This is burried and compressed volcanic ash from major Yellowstone eruptions. Once one visits one of these mines it becomes more apparent what the capacity of a true super volcano is to change the climate. Of course, none of these has occured post 1800. I’m just saying, keep it in mind when discussing climate and volcanism.
Hi Willis,
Thanks for bringing this up, but I do have a couple questions.
1) In your figure where you stack the various eruptions, you set the temperature for the year in which the eruption happened as “0”. This would assume that the volcano has no effect on temperature in the year of the eruption. Is this really a fair assumption? I’m especially thinking about eruptions which occur early in the year. Would it maybe be better to set the year before the eruption to zero?
2) You state “…particularly given the short lifespan of the stratospheric aerosols, as shown in Figure 2”. Given the short lifespan, is using the average temperature over the course of an entire year too long? Maybe that averaging is masking some of the (hypothetical) decrease in temperature. On the other hand, maybe a shorter averaging period (such as monthly) would just introduce too much noise.
1) If that was the case, year 0 would be the bottom, lower than both the year before and after, such as the 1832 line. However, since we don’t have a clear indication of that. However, without a consistent pattern, I would not think that a different baseline would change the conclusion
2) Yes, using the average over a year is too long for volcanos, and that is the entire point. This article is a rebuttal to claims that volcanos have a significant effect on long term global temperatures. Obviously they do not. You could almost certainly see the “year without a summer” on a monthly or weekly average, but it fades into the noise on long term scales.
benofhouston July 22, 2015 at 12:48 pm
Regards, Ben. While I love the certainly of your claim that “almost certainly” we could see volcanic effects on a monthly average, I fear that this is a marvelous example of why the plural of anecdote is not data.
My best advice to people is RUN THE NUMBERS YOURSELF BEFORE UNCAPPING YOUR ELECTRONIC PEN! For example, don’t just wave your hands and assert without evidence that we could see the volcanoes in the monthly dataset. Until you run the numbers, you don’t know that.
And please, see my post Missing the Missing Summer. Because as that post shows, even mighty Tambora is no more visible on a monthly scale than on an annual scale.
However, I must thank you for the thought. I’ve used the years because that’s what they used. But I have the data to pinpoint the month of the jump in the sulfate levels … so I could redo the analysis using monthly data.
So many rings in the circus … so little time …
w.
Actually it appears there is only one case from the graph where the year before was not higher so it could change the conclusion!
And using the average over a year is a big problem because in some cases the eruption occurred at the end of the year, in others at the start. And there may be cases where there were multiple eruptions months apart.
Repeating the exercise using the yearly average starting from the MONTH the eruption occurred would be best (but multiple eruptions months apart is still an issue).
Hi Benofhouston,
In reply to my question about whether using the year of the eruption as baseline, you stated “If that was the case, year 0 would be the bottom, lower than both the year before and after…” I don’t think that would necessarily be the case for a couple of possible reasons: 1) Any cooldown in the year of the eruption could be masked by averaging it with the pre-eruption “warmer” temperatures (As a thought experiment, imagine a hypothetical situation where an eruption on July 1 immediately lowered temperatures by 0.5 deg for exactly 18 months. The yearly average for the year of the eruption would only be down by 0.25 deg, while the year after the eruption would be down by 0.5 deg; year 0 would not be the lowest). 2) We don’t know what kind of lag there might be between the eruption and the (presumed) global climate signal. 3) There’s still the background of natural, non-volcanic variability, which I think Willis has presented a compelling argument as being able to pretty severely mask any volcanic signal that might exist.
I should explain that part of what made me ask the question in the first place was that I noticed that for almost every eruption (1963, I think, being the exception), year -1 was warmer than year 0 in Willis’ figure, which indicates at least the possibility of a climate effect in the year of the eruption.
From Willis “So many rings in the circus … so little time …”
I must thank you again for taking the time that you do to jump into circus rings such as this.
In case any one is wondering why volcanoes can be so effective , but only in the direction that suits ‘the cause ‘ the answer is that it is all part of the ‘magic of CO2’ that means cold is proof ,warmth is proof , rain is proof , draught is proof etc of CAGW , although to date ‘rains of frogs ‘ have not be claimed to be ‘proof’ it is only a question of time.
Willis when it comes to volcanic effects versus the climate your views are in the distinct minority.
http://www.leif.org/EOS/2011GL050168.pdf
This article is good but it needs to emphasize the prolonged minimum solar /volcanic climate connection( which it does not mention ), and other prolonged minimum solar climate connections such as an increase in galactic cosmic rays more clouds, a more meridional atmospheric circulation due to ozone distribution/concentration changes (which it does not do ) which all lead to cooler temperatures and more extremes .
In addition they do not factor the relative strength of the earth’s magnetic field.
When this is added to the context of this article I think one has a comprehensive explanation as to how the start of the Little Ice Age following the Medieval Warm Period may have taken place and how like then (around 1275 AD) is similar to today with perhaps a similar result taken place going forward from this point in time.
I want to add the Wolf Solar Minimum went from 1280-1350 AD ,followed by the Sporer Minimum from 1450-1550 AD.
This Wolf Minimum corresponding to the onset of the Little Ice Age.
John Casey the head of the Space and Science Center, has shown through the data a prolonged minimum solar event/major volcanic eruption correlation.
Today, I say again is very similar to 1275 AD. If prolonged minimum solar conditions become entrenched (similar to the Wolf Minimum) accompanied by Major Volcanic Activity I say a Little Ice Age will once again be in the making.
Milankovitch Cycles still favoring cold N.H. summers if not more so then during the last Little Ice Age , while the Geo Magnetic Field is weaker in contrast to the last Little Ice Age.
I would not be surprised if the next Little Ice Age comes about if the prolonged solar minimum expectations are realized in full.
http://spaceandscience.net/sitebuildercontent/sitebuilderfiles/ssrcresearchreport1-2010geophysicalevents.pdf
Once my low average solar parameters are attained we will see if this line of reasoning on the climate going forward is correct. I think it will be and that is the danger because mainstream keeps pushing global warming.