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.
Steven Mosher says:
March 16, 2012 at 10:17 am
Steven, I know “you don’t reach equilibrium”, and so would everyone else if you didn’t selectively mis-quote me. It’s not like you didn’t quote the full paragraph or something. You cut my dang sentence in half, it actually said:
You don’t do your reputation any good by playing fast and loose with my words, cherry-picking them and cutting sentences in half to distort my meaning.
And yes, although we don’t reach equilibrium, after three years of a drop in forcing half the size of a doubling of CO2 we should see some action.
w.
PS—And of course, you want to play your usual “I know something you don’t” nasty games. You say
“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.”
No, Steven the physics of the rest of the climate doesn’t tell me a damn thing about that, so how about you stop acting like a withholding jerkwagon and actually say what you mean? You claim we can’t look for a volcano’s effect in the observational record, but you’re too … what … I don’t even know what, but you want to make some point or something.
Steven, your drive-by type of “I know something you don’t know, you have to guess what it is, nyah, nyah” type of posting is insulting, repulsive, and very damaging to your reputation. I’ve seen comments on it in several places, none of them positive. Nobody likes it any more than I do. You are not doing yourself any favors with that kind of action. If you think we should not be able to look for the volcanic signature in the record despite the presence of other forcings, you’ll have to stop your childish game and simply explain why you think that. Because I’m not going to guess.
Willis – “Tamino and Rahmstorf, paywalled?”
Foster and Rahmstorf (http://iopscience.iop.org/1748-9326/6/4/044022) certainly isn’t paywalled. Click through to the PDF.
Most (the overwhelming majority I estimate) climatologists & solar scientists are fundamentally ignorant of spatiotemporal aggregation criteria impact on metrics. This is VERY serious fundamental (like 1+1=2 and up is the opposite of down) stuff. To help the layman relate: You could say they look at key markers of solar & lunisolar constraints through funky distortion lenses that can do things like flip things upside down, swap left with right, and make 3 look like it strictly equals 4 (…and worse: they don’t even realize this). It’s going to take awhile to help them sort out their conception, but who among the public will have patience if the heel-dragging continues for decades (as it appears it will)? They ignored warning shots and so now they have a hull breached by kinetic impact. Mainstreamers, quite simply: Assuming public trust extends to infinity is unwise. My advice: Rechannel research investment strategically beginning immediately. Tip: This is how you define who’s your enemy and who’s your ally in a capitalist system. Some of the best sharp-shooters are natural mercenaries. The public instinctively recognizes forces of nature. Harmonizing with nature is how to efficiently maintain composure and perhaps regain lost public trust.
Harold says:
March 16, 2012 at 10:23 am
So what? If the action of the volcanoes were as strong as the IPCC says, they should blow an El Nino right out of the water … but they don’t. Who did you say was fooling themselves?
Also, I haven’t a clue what you mean 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”. If you mean that I’m looking at first differences, you really should take a calculus course … and I also looked at the whole record.
Oh, please. I have read these reports, including Franklins, extensively. I did not say volcanoes have no effect. You’ve obviously learned to write, but you really should match that up by also learning to read. I said:
Your post sounds to me like you’re just upset because you couldn’t spot the volcanoes.
w.
I’ve looked at many climate time series (numerically) and have always been a bit disappointed to find that evidence for a few years of lower temperatures after a volcanic eruption is hard to spot or recognise. I thought it was just me and my methods – which are I supposed really geared to detecting more enduring changes and climate shifts. I’ll look again, just to check!
Robin
I cite the General Form of Le Chatelier’s Principle: “Any change in status quo prompts an opposing reaction in the responding system.”
This is a general prinicple taught in first year chemistry, and the atmosphere and hydrosphere are chemical systems, so the principle should apply.
WRT climate sensitivity, a directly relevant paper is Annan et al 2006, “Using multiple observationally-based constraints to estimate climate sensitivity” – (http://www.image.ucar.edu/idag/Papers/Annan_Constraints.pdf)
Volcanic forcings are included in the constraints. These end up with a large range, mind you, but combining the various points of evidence Annan concludes that:
Climate sensitivity “…has a maximum
likelihood value of 2.9C, and, using the IPCC terminology
for confidence levels, we find a likely range of 2.2– 3.9C
(70% confidence) and a very likely range of 1.7– 4.9C
(95%). We can also state that climate sensitivity is very
likely to lie below 4.5C (95%).”
On the other hand, applying an ‘eyecrometer’ to the temperature record against volcanic forcings, without accounting for all of the influences, is not a terribly strong argument.
Anecdotally, I bought a morotcycle in 1993. I lived in Michigan, and the temperature rarely got out of the 60’s all summer. I had to keep my jacket on to ride the entire season. It was the coolest Midwest summer I ever went through. Was I wrong to attribute this to Mt. Pinatubo?
I just love that music.
Clever, entertaining and instructive post Willis! Which goes a fair way toward illustrating the reason why squadrons of students are scouring the globe searching for evidence of the erupted volcanoes we missed during the past 12 years hahaha!
Bill Yarber says:
March 16, 2012 at 10:25 am
You are absolutely correct, Bill–I’ve been a student of process control and use a form of it in my current work. And the reason the AGW crowd completely ignores it is because there would be no “catastrophic” (anthropogenic) event they can conjur up to scare people–their interpretation of reality ignores how the real world behaves.
LearDog says:
March 16, 2012 at 11:19 am
The volcanoes on the sun have been reticent, to say the least.
Once again a topic is discussed without any reference to the work done 20 and 30 years ago. This is the legacy of the IPCC effectively diverting climate research to the single focus on CO2. I wrote about aerosols here;
http://drtimball.com/2011/atmospheric-aerosols-another-major-ipcc-omission/
and particulates here;
http://friendsofscience.org/assets/documents/FoS_Atmospheric_particulates.pdf
In addition I was coordinator and contributor (two articles) and organizer of a workshop on the global impact of Tambora through the National Museum of Canada; C.R. Harrington (ed.). The Year without a summer? : world climate in 1816, Ottawa: Canadian Museum of Nature, 1992.
The keynote speaker was John Eddy because he had noted and many of us had observed that global temperatures were already in decline because of the Dalton Minimum. It is interesting to speculate on the effect of Tambora if global temperatures were rising.
The proceedings of the Conference are available;
http://www.worldcat.org/title/year-without-a-summer-world-climate-in-1816/oclc/27429039
As a brief response to the question about how long the temperature impact is evident, it was generally agreed that with volcanoes that met the conditions identified in my article on particulates then the signal was detectable for about nine years. However, It was only detectable from a human sensibilities perspective for one year.
One factor not examine in our symposium, but which I have written about since is the portion of the light spectrum affected by the atmospheric conditions.
Here are four articles written variously from 1993 to 2000 in my monthly column in Country Guide, a farm journal. I wrote for 17 years but was fired when a new Board member was appointed.
volcanoes001.jpg
volcanoes002.jpg
volcanoes003.jpg
volcanoes004.jpg
“So what? If the action of the volcanoes were as strong as the IPCC says, they should blow an El Nino right out of the water … but they don’t. Who did you say was fooling themselves?”
Point me to the bit where they say that volcanoes have a much stronger influence than El Niños.
If you really didn’t have a clue what I mean about filtering out all the variation on longer timescales than a month, then do the following and it should become clear:
1. create a series of numbers, 100 values of 0, 100 values of -0.5, 100 values of 0
2. add to every number in the series a random number between -0.1 and 0.1
3. plot this series. Look at it very carefully.
4. subtract from every value in the series the previous value in the series.
5. plot this new series. What do you see? Amazing, huh? The step function has disappeared!
So you can see that in figure 1 you removed the very thing you claimed to be looking for. A bit inept, wouldn’t you say?
Your ideas about the magnitude of the effect of volcanoes are decades or even centuries out of date. Maybe, as you claim, you’ve read the literature. You certainly didn’t understand it.
Willis – look at figures 8, 9 and 10 in my book “What Warming?” if you have it. If you don’t have it, get it and look. The difference between El Chichon and Mount Pinatubo is what made me write that section. If you are unfamiliar with my book you will notice that I do not use any computer smoothing but apply a magic marker to raw data. You get a thick line that covers up most of the fuzz in the record and neatly outlines the correct global trend. Any use of computer will destroy data and should be avoided. The fuzz looks random not because it is random errors but because it represents local cloudiness variations that are randomly distributed. But my motivation was that the 1992/93 La Nina is marked everywhere as Pinatubo cooling, even on Roy Spencer’s web site, which would change this particular La Nina cooling into a volcanic cooling instead of a part of ENSO. That volcanic cooling claim started with Best who pontificated in 1996 that “Pinatubo climate forcing was stronger than the opposite warming effects of either the El Nino event or anthropogenic greenhouse gases in the period 1991-93.” The man had access to satellite data but he had no idea how to spot an El Nino in it. Back to El Chichon and Pinatubo. After assignings the 1992/93 La Nina to Pinatubo cooling Best goes on and states that “… surface cooling is clearly documented after some eruptions (for instance Gunung Agung, Bali in 1963) but not others – for example El Chichon, Mexico in 1982…” Wow! I had to check that. Since I had already worked out the theory of how ENSO works and identified all El Ninos and La Ninas in the satellite record it was easy to see the difference between El Chichpn and Pinatubo. El Chichon erupted exactly when a La Nina had just bottomed out and an El Nino was beginning. Pinatubo, on the other hand, erupted at the peak of an El Nino warming that was immediately followed by a La Nina cooling. Just plain luck, it seems: if an eruption is followed by a La Nina, that La Nina counts as volcanic cooling. But if it is followed by an El Nino, like El Chichon was, there is an unexplained absence of cooling that does not disturb them thinking that they found volcanic cooling elsewhere. That is a pretty big loose end in their theory which nevertheless is accepted by climate scientists. So, let’s test it and check out that Gunung Agung. It should be followed by a La Nina if my theory is correct. And so it is – a pretty steep drop just after the eruption. But before I could determine this I had to find the locations of El Ninos and La Ninas in ground-based temperature records. That turned out to be easy despite the fact that nobody had either noticed or bothered to remark about it. They are present in all temperature records going back to the nineteenth century. The BEST project showed a comparison of four temperature records. I looked at them and found the same El Nino peaks present in temperature curves from America, Europe, and Japan. There are differences of course and someone will eventually sort them out. My figure 10 shows the timing of seven volcanoes against HadCRUT3 temperature curve. It is hard to test it because cooling is not one of the things that is recorded about most volcanoes. But one thing is certain: there is no such thing as volcanic cooling in nature. It is simply a matter of lucky timing in relation to the ENSO phase that determines whether and how much “cooling” is associated with any particular eruption. When you start working out the details you will realize the importance of understanding the role ENSO plays in this area. Climate “scientists” prefer to get rid of it by computer smoothing.
I can see 2 to 3 W/m^2 cooling for a short time.
It is quite clear from fig. 6 that the eruptions took place just after a warming that triggered the eruptions according to all known AGW science.
It is then obvious from the same figure, that we will soon se a larger eruption.
You have to be a sceptic denier if you can’t see that.
Willis, you are becoming a waste of space on this blog site. Who do you think you are – what are your scientific qualifications to have definite views on everything that any science can offer including the meaning of life. “I hold that the climate system..according to my hypothesis..I devised a little game” !!!! in case you did bother to check in your virtual reality show, the real scientists spend their life-time working on a very small segment of the science that they are qualified to do, and the top scientists like Lindzen, Carter, Plimer, to name but few, still state, we simply do NOT know enough about the climate. So, please, stop wasting this excellent blog site space.
Wigley et al. (2005):
“Comparisons of observed and modeled coolings after the eruptions of Agung, El Chichón, and Pinatubo give implied climate sensitivities that are consistent with the Intergovernmental Panel on Climate Change (IPCC) range of 1.5–4.5°C. The cooling associated with Pinatubo appears to require a sensitivity above the IPCC lower bound of 1.5°C, and none of the observed eruption responses rules out a sensitivity above 4.5°C.”
http://www.agu.org/pubs/crossref/2005/2004JD005557.shtml
Forster et al. (2006):
“A climate feedback parameter of 2.3 +/- 1.4 W m-2 K-1 is found. This corresponds to a 1.0–4.1 K range for the equilibrium warming due to a doubling of carbon dioxide”
http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3611.1
I’ll take peer-reviewed research over the eyeball method, personally.
REPLY: And most everyone here will take Willis Eschenbach’s analysis over the serial deletion of comments and serial post facto article revisionism at “Skeptical Science” any day of the week and twice on Sundays. – Anthony
commieBob says:
March 16, 2012 at 8:30 am
The last super volcano, 600,000 years ago, nearly led to the extinction of the human race. http://lennyp.hubpages.com/hub/Supervolcanoes
================================================================
Did you mean the Toba super eruption?
It’s fascinating that the human population may have been as low as 10,000
I have added a seventh figure to the head post, folks might be interested to take a look. It shows the response of the albedo after Pinatubo, and how that affected the sunlight hitting the surface.
w.
darkobutina,
I happen to love reading Willis’ articles. They are very thought provoking. And his qualifications as a peer reviewed, published author are available. Do a search and see for yourself.
KR says:
March 16, 2012 at 11:07 am
Thanks, KR, I didn’t catch that.
However, I have indicated my objection to their method, removing the El Nino variations, above. Let me explain it again. Suppose you have a griddle on a stove. You measure the average temperature. Then you notice that one spot on the griddle tends to correlate with the entire temperature of the griddle.
So you regress the temperature of that spot on the temperature, and you subtract that regression from the temperature.
I hold that this is not a valid procedure, and that it distorts rather than simplifies the temperature record.
w.
PS—I don’t like to deal with Tamino in any case, I prefer actual scientists. He banned me from his site for asking hard questions.
tadchem says:
March 16, 2012 at 11:12 am
I agree, but people look at me like I’m totally nuts when I apply Le Chatelier’s Principle to the climate, so I don’t say that much.
w.
Willis – “I have indicated my objection to their method, removing the El Nino variations, above.”
It’s perfectly reasonable if that local variation leads to a global change. It can be (likely will be) of a different scale than the local influence, or even opposite in sign – but if the temporal pattern of the ENSO index matches changes in the global temperature, that global influence can be separated using multiple regression against a local index.
The whole idea of these attribution studies is to see how the dependent variable (global temperature) varies with influences of multiple independent (ie, you can’t get the ENSO index by summing combinations of volcanic and solar, for example, as they have different time patterns). And to that extent the attribution scalings are dimensionless relative numbers – not direct influences at local levels. I therefore cannot agree with your objection.