Volcanic Disruptions

Guest Post by Willis Eschenbach

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 are said to depress global temperatures, sometimes for years.

The idea that large volcanoes significantly cool the planet is widely accepted. This effect is built into the climate models, for example. It is a reflection of the dominant climate paradigm, which is that surface temperature is a linear function of forcing. Since it can be measured observationally that the volcanoes greatly reduce the global solar forcing, it follows that they must significantly affect the global temperature.

However, I hold that the climate system is not an inert slave of changes in forcing. I hold that the climate system immediately and actively responds to changes in forcing by adjusting things like albedo, cloud type, cloud formation times and locations, timing of Nino/Nina alterations, and the like, to quickly counteract any forcing changes.

Which means, of course, that according to my hypothesis, even very large volcanoes should a have very small effect on the global temperature. To see which hypothesis is true, mine or the standard AGW hypothesis, I devised a little game I call “Spot the Volcanoes”. Two of the largest volcanoes of the century occurred within a twenty year time span. See if you can tell where they occurred.

Figure 1. First difference (month-to-month change) in global surface air temperature. Timespan shown is twenty years. Two of the largest volcanoes of the 20th century are shown in this record. The volcano in the picture is Mt. Redoubt, Alaska, one of my favorite mountains.

In Figure 1, to make things a bit difficult, I show the month-by-month CHANGE in temperature. This is not the temperature itself, but the month-by-month change in temperature, called “delta T” (∆T). If the temperature is a function of the forcing, the eruptions should be making the temperatures drop for a while. So the game is, where in Figure 1 are the two eruptions? Make your choice before you take the jump …

The answer is shown in Figure 2 below. It contains the record of the atmospheric transmission over Mauna Loa. The two eruptions, of El Chichon and Mt. Pinatubo, are very apparent in the Mauna Loa (MLO) record. I have scaled the Mauna Loa record to the corresponding GISS estimate for the forcing from Pinatubo (in W/m2), in order to show the generally accepted size of the volcanic forcing.

Figure 2. As in Figure 1, plus Mauna Loa atmospheric transmittance observations. These observations are of the total amount of clear-sky sunlight making it through the atmosphere. 

Now, I can already hear folks grumbling, that this was not a fair game, that it was rigged because it was the first differences and not the actual temperature itself. And besides, most people don’t spend much time looking at first differences, so it was too hard. And perhaps those folks are 100% correct.

So let’s play a bonus round of “Spot the Volcanoes”, this time using the real temperature data. Figure 3 shows a stretch of the HadCRUT3 global surface air temperature record. This time it includes one smaller and two larger volcanoes. See if you can spot where the big ones erupted:

Figure 3. A stretch of the HadCRUT3 temperature record containing one small and two large eruptions. Don’t bother trying to find the small one.

So once again, the game is to spot two volcanoes.

Now at this time,

.

We’ve got to play the game show music,

.

. dee

. dee

. da dee dee dum

.

So as to hide the answer,

.

Until you make your choice, of the exact location of the two eruptions in Figure 3.

.

So here it is.

Figure 4. As in Figure 2, showing the eruptions of El Chichon (1982) and Pinatubo (1993). The small eruption is Mt. Agung (1963).

I’m sure you understand my point. There is nothing to see. The kinds of temperature excursions we see after the volcanoes are not different from the temperature excursions before the volcanoes.

How big an effect should we have seen, given the IPCC assumptions about climate sensitivity? Well, the average change in forcing over the three years following the Pinatubo eruption is ~ -1.7 W/m2. Now, that’s about half the forcing change expected from a doubling of CO2, maintained for three entire years … and where’s the response? Using the IPCC numbers, we should have seen a temperature drop of 1.4°C at equilibrium, and three years after the step change we should have seen at least a full degree of that …

Instead of a full degree of cooling after Pinatubo, or even half a degree, we see maybe a tenth of a degree of cooling.

But wait, as they say on TV … it’s even worse than that. The drop after Pinatubo may be just by chance, because after the earlier El Chichon eruption we see maybe a tenth of a degree of warming … and the average three year change in forcing for El Chichon is only trivially smaller than Pinatubo, at ~ -1.6 W/m.

So this is a great natural experiment regarding changes in forcing. From these observations, as near as we can tell, half the forcing change expected from a doubling of CO2 was applied for three full years, at two different times, and it resulted in … well, pretty much nothing.

So I’d say that the volcanic eruption data strongly supports my thermostat hypothesis, which says that changes in forcing are almost immediately and nearly completely offset by opposing changes in other aspects of the climate system.

w.

PS—Here’s the double bonus question … the UAH lower temperature record:

Figure 5. UAH MSU satellite based global lower tropospheric temperature record.

This time the game is a bit different. Are there one or two volcanoes in the record, and where is it / are they?.

Now at this time,

.

We’ve got to play the game show music like last time,

.

. dee

. dee

. da dee dee dum

.

So as to hide the answer,

.

Until you make your choice, of the exact location of the two eruptions in Figure 5.

.

So here it is.

Figure 6. As Figure 5 plus transmittance information.

Note that as with the surface temperature record, the globe cooled slightly after Pinatubo … and that as with the surface temperature record, the globe warmed slightly after El Chichon. And since the post-Pinatubo drop is indistinguishable from the post-1983 and the post-1988 drops, there is no reason to assume that the post-1991 drop is due solely to Pinatubo.

Which in my opinion is why all of the analyses focus on Pinatubo, while poor El Chichon is roundly ignored because it didn’t get the memo about causing a temperature drop.

PS—Does this mean volcanoes have no effect on the climate? No, it just means that because of the immediate and basically “equal but opposite” response of the climate system to forcing changes, the effect is much more local, much shorter lived, and much smaller than would be expected if the IPCC estimates of climate sensitivity were correct.

FURTHER READING: Climate forcing by the volcanic eruption of Mount Pinatubo

[UPDATE] People have asked for more information about how the climate responds to counteract the cooling action of the volcano. Figure 7 shows the response of the albedo to the Pinatubo eruption. The albedo immediately began to drop, allowing more and more sunlight to warm the surface.

Figure 7. Anomaly in post-albedo solar isolation for the period 1984-1998. The transmittance change due to the volcano is shown in red. Albedo data from Hatzianastassiou et al.

You can see that it’s not too hard to spot the volcano in this graph … which is exactly the reason why it’s so hard to spot in the other graphs.

w.

Advertisements

  Subscribe  
newest oldest most voted
Notify of
Latitude

…I like this game 🙂

The impact of volcanoes is interesting, because it forces the oceans to “divert from statistical means”. Twenty years ago I did some research concerning the reaction of the ocean; details here http://www.whatisclimate.com/conditions-for-the-protection-of-the-global-climate.html#_aa14 concluding –inter alias- :
“The fact that the air circulation did not reach its minimum until 1888 is not surprising. From the middle of the 1880s on, a “weakening” of the oceans in the higher latitudes must have become noticeable. The less heat energy the ocean feeds into the atmosphere, the weaker become the dynamics in the atmosphere. This also becomes clear when it is seen that three years after Krakatoa the temperatures above land rose more sharply than above the oceans.”

adolfogiurfa

Or…those temperatures´anomalies, being really a straight line, is meaningless.

Hoser

That’s interesting, but what does it really mean? We’ve seen other data where volcanic eruptions apparently have more obvious effects. You show a small sample, pick some graphs that are not necessarily random or representative of temperature data generally available. I’m not buying it yet.

You left out a few details that would have helped.
The strong 1982 El-Nino that can blunt the effect of a large volcanic eruption.Which is an atmospheric effect.
You also did not tell us what the level of dust and other particles were from Mt. Pinatubo and El Chichon.Were they that insignificant?
Generally the higher the dust and other “cooling” materials can go up into the upper atmosphere the greater the short term cooling effect.Since very few volcanoes in past push them high enough to do much of anything.That is why many eruption effects do not show up in the temperature record.
But a few that did such as Tambora,Krakatoa,Laki among others huge eruptions.They ALWAYS caused a big cool down for a short time after wards that clearly stood out.Some caused a lot suffering.
Tambora is a good case for significant climatic disruption that cause the famous phrase “the year without summer”
Year Without Summer: Effects Of Tambora Volcanic Eruption On Iberian Peninsula Studied For First Time
http://www.sciencedaily.com/releases/2009/02/090225161422.htm

Mike Baillie has been sparing with the volcanoes-do-it-all crowd for years. He thinks the older climate excursions result from extraterrestrial inputs: http://cosmictusk.com/?s=mike+baillie
I know he was controversial with skeptics when he claimed his data was proprietary, but he is a good egg and has been unfairly squelched by his critics (many of your same).

Jon Tuck

Good observations, good game. Your initial statement is a bit contentious though – i.e. that the climate always responds through a series of negative feedbacks. It’s a complex system with both positive and negative feedbacks. Other well-characterised systems with a mixture of postive and negative feedbacks (e.g. electrical circuits) tend to lurch between metastable states – a bit like moving a ping-pong ball around in an eggbox. Give it a little push and it will roll back to where it came from, push it hard enough and it will abruptly go somewhere else. Anyway, you’ve convinced me that recent volcanoes haven’t really done enough to push the ball out its current place, but not that the climate is immune to stronger forcings.

Matt Skaggs

Have you read the book “Volcano Weather” and what do you have on Tambora? If the global records are correct, Tambora had a huge effect and crops in the US failed due to mid-summer frosts. Unless I am missing something, your general hypothesis about forcing is vulnerable to a single, well-documented countervailing example.

commieBob

It just takes a sufficiently large volcano to have an effect on the climate. Consider Krakatoa for instance. http://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa

The eruption darkened the sky worldwide for years afterwards, and produced spectacular sunsets throughout the world for many months.

It seems likely that the ensuing temperature drop was not just a coincidence.
The last super volcano, 600,000 years ago, nearly led to the extinction of the human race. http://lennyp.hubpages.com/hub/Supervolcanoes

Geoff Alder

Willis
As an unapologetic simpleton, may I say how much I enjoyed this article. Indeed, I greatly enjoy most of them–at least those that I can partially understand!
Thank you for all your hard work. (But there can be no doubt you must take great pleasure from putting them all together.)
Geoff Alder

Neil Jones

So Gia works, balancing out the hiccoughs along the way as was originally proposed. Sad even Gia’s wondrous working have to be ignored for the sake of power and money.

wsbriggs

It seems we have more than a few “Playas”.
For those who’ve forgotten about Pinatubo, we had an ozone hole at the North Pole following the eruption.
For those who flipped up Krakatoa, even Gaia takes time when she has a rant to restabilize. Nonetheless, Willis’ point still holds, with the ueber tonnage of dust, ash, SO2, etc thrown into the atmosphere, the world still recovered within a short (geologically speaking) time period. In my mind, 5 years isn’t forever – Wikipedia, 1883 eruption of Krakatoa. It would take strong persistent negative feedback to fix something of that scale that fast.

BM

I got the second volcano exactly right in the first graph. I got the timing first volcano right if you spot me much larger margin of error on the second graph. On the last graph I got both volcanos right, the second spot on, and the first with a wider margin of error.
Had you not said how many volcanos I would have guessed that there were a whole lot more than I was guessing.

Sandy

The Eschenbach Thermostat Theory suggests that after a major eruption, with insolation at the surface reduced, ITCZ Cu-nims should start later in the day.
Could this be measured??

KR

It’s always worth noting that there isn’t just one forcing in effect – we have solar, ENSO, volcanic, anthropogenic GHG’s, etc. When you add _all_ of the forcing changes together it is rather more clear – instead of trying to spot changes from volcanic forcing when, for example, ENSO and solar changes are occurring at the same time.
I’ll also point out that looking at the changes in temperatures relative to forcing changes supports the climate sensitivity estimates – if you actually run the numbers…
Foster and Rahmstorf 2011 – forcing attribution over the last 30 years (http://iopscience.iop.org/1748-9326/6/4/044022)
Lean and Rind 2008 – forcing attribution 1896 to 2006 (http://content.imamu.edu.sa/Scholars/it/net/lean2008gl034864-marked-attached.pdf)

DirkH

“PS—Does this mean volcanoes have no effect on the climate? No, it just means that because of the immediate and basically “equal but opposite” response of the climate system to forcing changes, the effect is much more local, much shorter lived”
I disagree; I see it like this: All of the time, that oscillator that quasiperiodically creates La Niña / El Niño events, is charged by UV penetrating the oceans down to the boundary layer. The forcing modulation influences how fast this “heat capacitor” is charged. The timing and direction of the next event is influenced by that; but as it can take quite a while for it to occur, consequences of the volcanic eruption can be hidden for an unpredictable amount of time.
With regards to the immediate reaction of the atmosphere, though, Willis seems to be right.

Anopheles

In the cases of Tambora and Krakatoa, can we see how long it took for the temperature to come back? Would the apparently short time mean mean response is pretty quick, and that therefore heat in the pipeline or long approaches to ‘equiliibrium’ are nonsense?

Amazing. Even being roughly familiar with the changes in temps over the last decades, I still got it wrong! What this tells me is that even MASSIVE events by themselves don’t drive climate but rather a million factors affect what happens. Great demonstration.

Dennis Nikols, P. Geo

Thanks for the discussion. Most of what people call large eruptions are in geological terms a quite small to minor. Fortunately the truly big ones are very infrequent.

Willis, good article.
In this quote:
“I hold that the climate system immediately and actively responds to changes in forcing by adjusting things like albedo, cloud type, cloud formation times and locations, timing of Nino/Nina alterations, and the like, to quickly counteract any forcing changes.”
Are you suggesting that there is a natural “balance” of/on/by/for the planet?

The other possibility is that you have demonstrated that the temperature anomaly record and global average temperature information is useless for climate study as it cannot even find evidence of major forcings.
The apocryphal evidence was that winters were noticeably more severe following the El Chichon eruption. The effect did not show up until the following winter. In Colorado we had the longest period of continuous snow cover on the ground in the Denver metro area on record (63 days) stretching from the Thanksgiving day blizzard of 1983 (21.5 inches snow fall over 37 hours ) with high winds. The snow cover persisted until January 27 of 1984.
Granted this is only one local weather anomaly but the public perception at the time following these major volcanic eruptions was that the following winters 6 – 18 months after the event were noticeably harsher than usual.
Many of us question the validity and usefulness of the temperature records and the use of global average temperatures and temperature anomalies for climate study. In view of that fact, it is just as likely that your demonstration shows the lack of validity of those temperature records, as it does demonstrate your hypothesis that the world climate actively resists forcing by compensation.
Although I generally agree that thermal convection and the other related consequences of strong thunderstorm development is a powerful component of the “heat engine” we call weather, we can’t have it both ways and say the temperature records are worthless when arguing one hypothesis and then on another day use those same records to falsify a different hypothesis.
Larry

Willis Eschenbach

Sandy says:
March 16, 2012 at 9:03 am

The Eschenbach Thermostat Theory suggests that after a major eruption, with insolation at the surface reduced, ITCZ Cu-nims should start later in the day.
Could this be measured??

Thanks, Sandy. I’ve been wondering about that myself. Unfortunately, the datasets that might be of use (TAO buoys, Argo floats, etc.) generally don’t start until after Pinatubo.
w.

Greg Holmes

Good hypothesis, not sure its spot on but is looking likely. I love the real world versus models, real wins every time.

M Courtney

Marvellous.
The climate models use of forcings which are derived from Pinatubo seems to be blown out of the sky.
However, just because the models are wrong it doesn’t mean that all volcanoes will be of localised impact. There could be a scale of explosion (bigger then these two) which breaks out of the lower atmosphere and into the jet stream. If the volume of dust was big enough that could cause a global impact.
Science fiction, I know, but mega-volcanoes (steam explosions) are supposedly on a different scale.

James of the West

The post high powered volcano drops are obvious in the anomaly record but temporary (2 or 3 years). the IPCC assumes they know and understand all climate forces, which is where the wheels fall of their wagon – it tends to make them artificially increase the sensitvity to the forces that they do consider because they cannot attribute any force to the variables they do not consider (clouds, GCR aerosols etc).

Allan MacRae

Very interesting Willis.
The climate system seems highly stable in response to volcanic disruptions…
…in addition to being highly insensitive to increases in atmospheric CO2.
Instead of searching in vain for evidence of significant human impact on climate, we should be looking for a huge shock absorber in the climate system.
It’s also interesting to see how often actual climate data tends to disprove the CAGW (very-scary global warming) hypothesis.
The CAGW hypothesis is dying – every day that goes by provides new data to further falsify the global warming scare.
This is why the global warming fraudsters have tried to whip up a public frenzy to demand emergency action to “fight global warming”, with very-scary talk of a climate “tipping point” of no return. There is no such scientific tipping point – it is pure political gamesmanship.
The real tipping point the warmists fear is that of public opinion – if they cannot stampede a gullible public into handing them power quickly, then the decade-long absence of global warming, or even the advent of global cooling, will destroy their last tattered shreds of credibility.

Willis Eschenbach

Anopheles says:
March 16, 2012 at 9:09 am

In the cases of Tambora and Krakatoa, can we see how long it took for the temperature to come back? Would the apparently short time mean mean response is pretty quick, and that therefore heat in the pipeline or long approaches to ‘equiliibrium’ are nonsense?

Dunno … Tambora was 1815, Krakatoa was 1883. In neither case is our data much good, nor do we have actual measurements of the transmission loss. I’ll take a look at 1883 when get a chance.
w.

gnomish

well, when carl sagan started the rock.star.scientist.saving.the.world.from cataclysm.by.lying.with.a.sincere.expression industry, he founded his ficticious enterprise precisely on the idea of aerosol cooling effect (from nucules, dontcha know).
but when kuwait was burning… and there were no global effects as he prognosticated with his prognosticator well lubed…
well, that was the last we heard out of his sorry lie hole.
since then, of course, they’ve learned that there are no consequences for getting flat out busted for outrageous lies – because lying for the cause is just a measure of one’s devotion.
it’s lies all the way down.

Willis Eschenbach

KR says:
March 16, 2012 at 9:03 am

It’s always worth noting that there isn’t just one forcing in effect – we have solar, ENSO, volcanic, anthropogenic GHG’s, etc. When you add _all_ of the forcing changes together it is rather more clear – instead of trying to spot changes from volcanic forcing when, for example, ENSO and solar changes are occurring at the same time.
I’ll also point out that looking at the changes in temperatures relative to forcing changes supports the climate sensitivity estimates – if you actually run the numbers…
Foster and Rahmstorf 2011 – forcing attribution over the last 30 years (http://iopscience.iop.org/1748-9326/6/4/044022)

Thanks, KR, Tamino and Rahmstorf, paywalled? If either one told me it was raining, I’d check out the window before believing them. No way I’ll pay to read garbage from people who censor scientific opinions and spend their time grinding their axes, I’d advise you do the same.

Lean and Rind 2008 – forcing attribution 1896 to 2006 (http://content.imamu.edu.sa/Scholars/it/net/lean2008gl034864-marked-attached.pdf)

Lean and Rind claim a cooling of about – 0.2°C for El Chichon, and about – 0.1°C for Mt Agung. Since those don’t show up in the surface record at all, I’m not sure what you mean when you say that “supports the climate sensitivity estimates” …
w.

Steve Oregon

sunsettommy says:
March 16, 2012 at 8:20 am
You left out a few details that would have helped.
What a perfect message to send to the IPCC.

Willis Eschenbach

Larry Ledwick (hotrod) says:
March 16, 2012 at 9:10 am

The other possibility is that you have demonstrated that the temperature anomaly record and global average temperature information is useless for climate study as it cannot even find evidence of major forcings.

Many of us question the validity and usefulness of the temperature records and the use of global average temperatures and temperature anomalies for climate study. In view of that fact, it is just as likely that your demonstration shows the lack of validity of those temperature records, as it does demonstrate your hypothesis that the world climate actively resists forcing by compensation.

Thanks, Larry. If the satellite record didn’t agree in all major details with the ground record regarding what happened after Pinatubo and El Chichon, I’d say you might have a point.
But since the satellite record did agree as to the timing and the size of the eruption-caused variations, I’d say your claim is incorrect.
w.

Willis Eschenbach

James of the West says:
March 16, 2012 at 9:19 am

The post high powered volcano drops are obvious in the anomaly record but temporary (2 or 3 years).

No, they are not “obvious”, that’s the whole point of the game.
Most people can’t guess where the vocanoes are, and if it were “obvious”, everyone would be able to guess it spot on. There is actually a rise after El Chichon.
And it is not clear if any of the variations are much more than random swings. The records contain many other drops the size of the swing after Pinatubo, so we have no assurance that the Pinatubo swing is not partially natural …
w.

Steve from Rockwood

Nice work Willis. It is interesting to note that where there is data, the evidence is slim and where there is no data, the claims are huge.

Willis
I think the effects of volcanoes exist after the explosion, but it is just hidden within the larger natural variation. If you remove the known short and long term variations, the effects of the volcanoes will be more evident.

MarkW

Matt Skaggs says:
March 16, 2012 at 8:28 am
—-
Another possibility is that there is a limit to how much the negative feedbacks can compensate for.
El Chichon and Pinatubo weren’t big enough to swamp the feedbacks, Tambora was.

GeneDoc

Nice read Willis, I very much enjoy your empiric approach. If I understand your post correctly, you suggest that the Earth ocean/atmosphere system responds to reduced insolation in ways (largely unknown) that tend to maintain surface atmospheric temperature. But surely energy is lost somewhere? (and it’s a tragedy that we don’t know where!). Oceans are a huge heat sink, and I would imagine that they act as the principle buffer of atmospheric temperature change over short time intervals. But what about more drastic changes in energy influx? Or longer time intervals?
I find limit cases instructive (if completely unrealistic):
How long might the temperature be buffered if insolation went abruptly to zero? That is, what is the rate of loss of energy from the system and how much energy is present? The claim is that it’s well balanced, and that must be true at steady state. But the total heat stored in the system without input must provide some sense of the buffering capacity. And surely energy efflux could not fall to zero.
Alternatively, what might you expect from a -1.7 W/m2 reduction ad infinitum? A few years seems well buffered, but at some point the Earth ocean/atmosphere system must adjust to a lower total energy. If that doesn’t show up in surface air temperature, where is it?

paddylol

Willis: How are the nasty gases and acids that spew into the atmosphere during eruptions accounted for? What are their impacts on greenhouse gas levels? Do the eacerbate or moderate atmospheric and surface temperatures?

Anything is possible

Play your game with volcanoes and lower stratospheric temperatures Willis, and you’d lose every time……
http://www.metoffice.gov.uk/hadobs/hadat/images/update_images/global_upper_air.png
It is not the immediate effect (strong warming) that intrigues me so much as what happens afterwards. When the aerosols (presumably) clear out, lower stratospheric temperatures fall dramatically to a level lower than they were before the eruption and, so far at least, there is no clear sign of any sort of recovery.
What’s up with that? Anyone?

Sandy

Probably the best test of the EschenTherm Theory would be from those photos of the sun-side earth.
A white pixel count in the band 20 deg N / S would give an ETT index which should drop after an eruption.

Werner Brozek

Le Chatelier’s Principle initially just basically applied to simple systems, I believe a much more complicated set of Le Chatelier’s types of Principles could be developed for climate, but we are not there yet. Perhaps 50 variables may be changing at any given time.
I believe Lubos’ article on Le Chatelier’s principle and climate would be an interesting read: http://motls.blogspot.com/2007/11/le-chateliers-principle-and-natures.html
From this article:
“But the idea that positive feedbacks dominate or that they are the ones who win at the end simply contradicts basic laws of thermodynamics.”

Willis Eschenbach says: March 16, 2012 at 9:21 am (RE: Anopheles says)
__”Dunno … Tambora was 1815, Krakatoa was 1883. In neither case is our data much good, nor do we have actual measurements of the transmission loss. I’ll take a look at 1883 when get a chance.“
It is worth to investigate Krakatoa more deeply, as climatology could have learned a lot about the functions of the oceans in the global system. For example :
___“In total, the blockage effect has been calculated at an average of approximately 10% over a span of four years, whereby the reduction of solar energy in the northern hemisphere (Paris) was at its greatest in fall of 1885, reaching a value of 25%. It would seem that a reduction of solar radiation of such proportions would necessarily have a long-lasting effect on atmospheric dynamics. But supposedly the average temperatures fell only slightly and the atmospheric circulation in 1884 was above normal and did not sink to a strongly developed minimum until 1888. While the equilibrium of the world of statistics may not have been disturbed by Krakatoa, events were rather different in the world of nature. Without the stabilizing effects of the ocean, the effect of Krakatoa would have been catastrophic. A person sitting in warm bath water does not experience any discomfort when the heating is turned off – at least, not right away.” Reference sees comment above:
ArndB says: March 16, 2012 at 8:09 am

“Using the IPCC numbers, we should have seen a temperature drop of 1.4°C at equilibrium”
you don’t reach equillibrium. You cannot simply compare one of many forcings against the record which is the result of all forcings. cannot. It will not work and the physics of the rest of the climate should tell you why you cannot.
Better is to do a model like Lucia’s Lumpy. Then you will see how much variance volcanic forcing accounts for. The total temperature response is a function of all the forcings, some of which are lagged, others of which are not.

Harold

You are fooling yourself in some quite inventive ways here. Firstly by filtering out all variation on timescales longer than one month, and then thinking that this means that there are no variations on timescales longer than one month. Secondly by pretending that there are no other influences on the climate besides volcanoes. El Chichón’s eruption coincided with a very strong El Niño.
And you appear to be entirely unaware of the extensive body of literature in which the effects of volcanoes on the global climate are observed. It goes right back to 1783, when Benjamin Franklin realised that the eruption of Laki in Iceland was the cause of an aerosol haze which dramatically reduced northern hemisphere summer temperatures.

Bill Yarber

Process control theory is being totally ignored by the AGW crowd. Process control engineers can easily determine that Earth’s climate (temperature) is dominated by NEGATIVE feedbacks, not positive. If CO2 concentration was such a dominant forcing, Earth’s climate would have saturated into a run-a-way greenhouse condition several million years ago when the average temperature was 9+C greater than today and CO2 concentrations were 2-7,000 ppm. It didn’t!
Systems dominated by positive feedbacks are very unstable and will eventually saturate at one extreme or the other. Only systems dominated by negative feedbacks are stable enough to find equilibrium point(s) when not perturbed by outside influences. Although Earth’s climate is chaotic on short geologic time scales, and has demonstrated larger swings from glacial to interglaicial periods, it is fundamentally stable with fluctuations of little more than +/- 4C, with only a few exceptions. Even the LIA was only 2C colder than today at its worse with many much warmer years interspersed during the 500 year length of the LIA.
That said, astronomical variations in orbit and tilt are sufficiently strong forcings to drive the Earth into glacial and intergalical periods because 3-5 million years ago, the South American plate joined with Central America and changed the deep ocean currents, reducing heat transfer from the equator to the poles and allowing glaciers to form and advance over much of the northern land masses. Man, and most fauna and flora, have survived and flourished during the past 2 million years when ice ages came and went on 130,000 year intervals.
Bill

AnonyMoose

An interesting game. The only way to win is to not explode a volcano.

kadaka (KD Knoebel)

Willis, you’re making me start thinking “the climate” is best modeled, considering the thermal sources and sinks of the oceans and the ice caps, as a 10 ton boulder in a smooth bowl-like depression, with “natural variation” being it moving around like a billiard ball that won’t come to rest as assorted forces keep buffeting it. All the volcanoes did was try to kick the boulder.
And Hansen and his ilk are arguing the slow steady pressure of CO₂ on this moving boulder, which will lead to “positive feedbacks” pushing it even harder, will push it over the rim and it’ll naturally roll upwards to somewhere even higher, from which it may never roll down to that depression again. When all that really happens is the boulder rolls away from the CO₂ stick poking it.
Yup, they are insane.

Vince Causey

Let me guess – the cooling is “in the pipline” to emerge many decades hence.

Jim G

Willis Eschenbach says:
March 16, 2012 at 9:21 am
Anopheles says:
March 16, 2012 at 9:09 am
“In the cases of Tambora and Krakatoa, can we see how long it took for the temperature to come back? Would the apparently short time mean mean response is pretty quick, and that therefore heat in the pipeline or long approaches to ‘equiliibrium’ are nonsense?
Dunno … Tambora was 1815, Krakatoa was 1883. In neither case is our data much good, nor do we have actual measurements of the transmission loss. I’ll take a look at 1883 when get a chance.”
Willis,
I was thinking along the same lines as Anopheles. Though more generally, in the geologic time frame, some of the truely major eruptions, such as some of the Yellowstone blows, may not fit your theory. In the scheme of volcanic activity, on a geologic time scale, those you have chosen were relatively minor by comparison based upon geologic evidence such as bentonite deposits, etc. There must be some middle ground between the super volcano, which can change the face of the planet for a very long time and those you have cited that would be interesting to look at were data available. Very interesting work, though, in any case. Thank you.
Jim G

Willis Eschenbach

Girma says:
March 16, 2012 at 9:46 am

Willis
I think the effects of volcanoes exist after the explosion, but it is just hidden within the larger natural variation. If you remove the known short and long term variations, the effects of the volcanoes will be more evident.

Which “known short and long term variations” would you suggest I remove?
I am very leery of removing what people call “El Nino variations” or “AMO variations”. These generally refer to the temperature in a particular part of the planet, the “El Nino 3.4 region” or the North Atlantic or somewhere else.
I don’t see the theoretical justification for saying “From the world’s temperature, we will subtract the regression of the variations of the Nino 3.4 area on the world’s temperature” … I’m sorry, but that doesn’t seem like a mathematically valid operation, to subtract part of the temperature from itself. We could do the same for say the North Atlantic, remove the regression of the North Atlantic on the world temperature … or heck, we could remove the regression of the entire world temperature on the world temperature, and end up with a flat line …
Not sure if that’s clear, but I hope you see the problem.
w.

The 20th century was actually a mild period for volcanoes and shouldn’t be considered “normal”.