# Why Volcanoes Don't Matter Much

Guest Post by Willis Eschenbach

The word “forcing” is what is called a “term of art” in climate science. A term of art means a word that is used in a special or unusual sense in a particular field of science or other activity. This unusual meaning for the word may or may not be logical, but each field has its terms of art, and it’s useless to complain that they don’t make sense. The IPCC defines “radiative forcing” as follows:

Radiative forcing is the change in the net, downward minus upward, radiative flux (expressed in W m–2) at the tropopause or top of atmosphere due to a change in an external driver of climate change, such as, for example, a change in the concentration of carbon dioxide or the output of the Sun. Sometimes internal drivers are still treated as forcings even though they result from the alteration in climate, for example aerosol or greenhouse gas changes in paleoclimates.

Now, the current climate science paradigm says that regarding the things that affect temperature, everything averages out in the long run except for any changes in total forcing. The current paradigm further says that the future evolution of the climate can be forecast by the simple linear relationship given as:

Change in temperature equals climate sensitivity times change in total forcing.

Me, I think that’s simplistic nonsense, but let’s set my opinion aside for a bit and compare their forcing claims to the actual observations of the changes in forcing. As an example, let me use the forcings that are the result of volcanic eruptions. The larger eruptions blast aerosols (various molecules and minerals) into the stratosphere, reducing the incoming sunshine. These forcings have been estimated by Sato  as being of the following amounts:

Figure 1. Volcanic forcings estimated by Sato et al.  http://data.giss.nasa.gov/modelforce/RadF.txt  Forcings are negative because they represent a reduction in available solar energy due to volcanic aerosols. The large eruption at the far right is Pinatubo in the Philippines, 1991, and the eruption to its left is El Chichon, Mexico, in 1982.

You can see that some eruptions, like that of El Chichon, produced a much larger aerosol cloud in the northern hemisphere (red) than in the southern (blue), while others like Pinatubo were more equal in the distribution of the aerosols between the hemispheres. In all cases, the hemisphere where the volcano is located shows the greatest effect from the eruption.

As I mentioned above, I think that the idea that the temperature slavishly follows the changes in forcings to be a fundamental misunderstanding of how the climate system operates. Instead, I say that although initially the temperature responds to the forcings, soon the climate system responds to the resulting changes in temperature by changing the forcings themselves, often in very non-linear ways. In particular, I have presented plenty of evidence that the climate system responds to increasing tropical temperatures by varying the timing and strength of the daily emergence of the cumulus cloud field. Part of the climate system response works like this:

On warmer days, the emergence of the tropical cumulus cloud field is both earlier and stronger. This cuts down on the available solar energy by reflecting more of it back to space. The high cloud albedo means that less sunlight reaches the surface, so the surface cools.

And on cooler days, the opposite occurs. The tropical cumulus field emerges later, and is weaker. As a result, the day warms up more than it would otherwise, because there is less cloud albedo and thus more available solar energy.

All that is required to show that this effect exists is to show that tropical albedo is positively correlated with temperature … as I have done here, here, and here.

Now, if we assume for the moment that my theory is correct, what kind of climate response would we expect to find from a volcanic eruption large enough to put aerosols into the stratosphere and cause some global cooling? Well, eruptions reduce available solar energy in two ways—increased reflection from white aerosols, and increased absorption from dark aerosols.

So the first thing to happen after the eruption would be the reduction in incoming sunlight from the increased albedo and increased stratospheric absorption. Then after the decreased sunlight actually starts to cause widespread cooling, the climate system would respond. We’d expect the climate system response following such an eruption to have the following characteristics:

Right after the eruption, there would be a reduction in available solar energy, due to the volcanic aerosols in the stratosphere.

This initial eruption-induced reduction in available solar energy would be both deeper and sooner after the eruption in the hemisphere where the eruption occurred than in the opposite hemisphere.

As a result, the corresponding climate reaction in the eruption hemisphere would also both be deeper and occur sooner than the climate reaction in the opposite hemisphere. In other words there will be a dose-related effect, where a larger reduction is met with a larger climate reaction.

The form of the climate reaction will be an albedo reduction, which will cause increase in available solar energy. The increase in available energy will be of the same order of magnitude as the corresponding decrease due to volcanic aerosols.

With those predictions derived from my theory about the nature and timing of the climate response, we can compare them to what actually happened when Mount Pinatubo erupted. I’ve taken the albedo records for the globe and for each hemisphere individually, and analyzed what happened after the eruption of Pinatubo in June of 1991. This gave me the anomaly in the amount of solar energy that is actually available to the climate system. Figure 2 shows three variables for the period 1984-1997, which includes the eruption of Mt. Pinatubo on June 15, 1991.

First, in black, is a closer look at the same dataset shown in Figure 1. Black shows the global average of the Sato volcanic forcing data for the period 1984-1997.

Second, in violet, is the aforementioned anomaly in the amount of incoming sunshine, in watts per square metre. This is the “available energy”, meaning the solar energy that remains after the albedo reflections.

Third, in gold, is the amount of incoming solar energy that is absorbed in the stratosphere. Recall that volcanoes affect the sunshine in two ways—changes in reflection (violet line) and changes in absorption (gold line). The gold line shows the reductions from absorption of solar energy by stratospheric aerosols.

Figure 2. Sato estimated volcano forcing (black), available solar energy anomaly after albedo (violet), and stratospheric absorption forcing (gold). The observed values (violet and gold) are expressed as anomalies around the value they had the month before the eruption. See below for methods and data sources.

Now, the first thing I noticed is that immediately after the eruption, all three datasets agree with each other—as we would expect, there is a precipitous drop in downwelling solar radiation. However, after that they go their separate ways, so it’s hard to tell what the overall effect of the absorption and the reflection might be.

For that kind of comparison, I use a running post-eruption average. This is the average forcing over the period from the date of the eruption to the date in question. So for example, the data point for January 1996 represents the average forcing from the date of the eruption until January of 1996. Figure 3 shows that type of post-eruption average applied to Figure 1, with the actual Figure 1 data shown grayed out in the background for reference.

Figure 3. Post-eruption averages. Total observed eruptive forcing [reflection (violet) plus absorption (gold)] is shown in yellow. Other colors as in Figure 1 — black is the Sato estimate of total volcanic forcing; violet is available solar anomaly after albedo reflections; gold is stratospheric absorption anomaly. Each point on the graph represents the average forcing from the eruption until that date.

The important thing to note is that from the eruption to the end of the record (end of 1997) the Sato forcing estimate (black line) has an average forcing of about minus one watt per square metre (W/m2). However, the observed change in total forcing of the period (yellow line, sum of purple (albedo forcing) and gold (absorption forcing) is a bit more than plus one watt per square metre.

Also, the speed of the climate response is visible in Figure 3. The total forcing (yellow line) follows the Sato forcing estimate (black line) for the first four months or so after the eruption. But after that, while the Sato calculated forcing continues to become more and more negative, the observations show that the total observed forcing does not ever become much more negative than it was at four months after the eruption. Instead, it runs level for about a year, and then rapidly increases. By the end of 1993, the observed post-eruption average forcing has returned to pre-eruption values … while the Sato theoretical forcing is still at minus two W/m2.

Now, Figures 2 and 3 show the global situation. We also have data for each hemisphere separately. This will let us observe the difference in the response of the climate in the two hemispheres. Here are the observed forcing and the Sato theoretical forcing for the northern and southern hemisphere.

Figure 4. As in Figure 2 but by individual hemisphere. The two panels show the Sato estimated forcing (black), the solar absorption forcing (gold), and the available solar energy after albedo (upper panel, red, northern hemisphere; lower panel blue, southern hemisphere)

The most notable difference between the hemispheres is the deep drop in available solar energy in the northern hemisphere (red line, upper panel) during the months immediately following the eruption. I note also that following that initial drop, the amount of available energy in the NH steadily increases in both the absorption (gold) and reflection (red) datasets.

To conclude this analysis I looked at the post-eruption averages for the individual hemispheres. Figure 5 shows those results:

Figure 5. As in Figure 3 but by individual hemisphere. These show the running average starting at the time of the eruption and moving forwards.

In the northern hemisphere we can see that the initial drop in forcing was almost as large as the Sato estimate. However, from there, the climate response kicked in, and the amount of available energy started to rise rapidly. In the southern hemisphere, on the other hand, the response was smaller and initially slower.

However, once the SH response began, the available solar energy rose very quickly. Both hemispheres took about the same amount of time, about two years, for the average forcing over the post-eruption interval to return to zero.

And in both hemispheres, the eventual response was nearly identical—the average change in total available sunshine at the end of the record is about plus a watt and a half per square metre, compared to the Sato estimate which has an average change to the end of the record of minus one watt per square metre.

Conclusions: The main conclusion that I draw from this is that the central paradigm of modern climate science is wrong—temperature does not slavishly follow the forcings.

To the contrary, when the tropical temperature changes, the solar forcing subsequently changes in the opposite direction, negating much of the effect of the volcanoes.

And in particular, the observations agree with the theoretical predictions, which were:

Right after the eruption, there would be a reduction in available solar energy, due to the volcanic aerosols in the stratosphere.

This initial eruption-induced reduction in available solar energy would be both deeper and sooner after the eruption in the hemisphere where the eruption occurred than in the opposite hemisphere.

As a result, the corresponding climate reaction in the eruption hemisphere would also both be deeper and occur sooner than the climate reaction in the opposite hemisphere. In other words there will be a dose-related effect, where a larger reduction is met with a larger climate reaction.

The form of the climate reaction will be an albedo reduction due to the temperature reduction, which will cause an increase in available solar energy. The increase in available energy will be of the same order of magnitude as the corresponding decrease due to volcanic aerosols.

These theoretical predictions are all visible in the graphs above, and they lead back to the title of this piece. The reason volcanoes don’t matter much is that the climate rapidly responds to re-establish the status quo ante. Yes, eruptions do put loads of aerosols into the stratosphere; and yes, these aerosols do cut down available solar energy; and yes, this does have local effects in space and time … but because available solar energy in the tropics goes up as the temperature goes down, the balance is quickly restored. As a result of this and other restorative phenomena, the climate system has proven to be surprisingly insensitive to such variations in forcing.

My best regards to everyone,

w.

The Usual Request: If you disagree with someone, please quote the exact words that you disagree with, so we can all be clear both who and what you are objecting to.

Methods and Data

Sato Theoretical Forcing: The Sato data is from here. Following Sato, I have used the aerosol optical depth (AOD) to estimate the forcing. Sato says that the forcing is estimated as a linear function of the AOD, which seems reasonable. I have used his formula for the “instantaneous” forcing (as opposed to the “equilibrium” or other forcings), since we are discussing the immediate effects of the eruptions.

Available Solar Energy Anomaly After Albedo: For the albedo data, I digitized the albedo shown in Figure 5(b) of the most interesting study, Long-term global distribution of Earth’s shortwave radiation budget at the top of atmosphere,  by Hatzianastassiou et al.  I multiplied the monthly (1 – albedo) by the monthly TOA solar to get the absolute value of the available solar energy after albedo reflections. Then I  subtracted the “climatology”, which means the monthly averages, from that dataset to get the anomaly in available solar energy

Stratospheric Absorption: While researching for this post, I had an interesting insight about the increase in stratospheric absorption of solar energy after an eruption. This was that I could use the change in stratospheric temperature to calculate the amount of additional sunlight being absorbed, using the Stefan-Boltzmann relationship. For the stratospheric temperatures, I used the UAH satellite based estimate of the lower stratosphere, Version 6.0beta2, available here. Yes, I am aware that this is an uncertain estimate, but it’s accurate enough for a first-order analysis such as this one.

Sensitivity to Assumed Emissivity: I used the most conservative assumption, that of a blackbody relationship with emissivity=1. If we assume a graybody, the change in solar absorption corresponding to a given temperature difference goes down in proportion to the change in emissivity. This reduces stratospheric absorption forcing. And this in turn increases the difference between the observed (yellow line) and the Sato theoretical forcings (black line) in the period immediately after the eruption, but makes little difference in the later years because the stratospheric absorption term is small. For an example of the change in the early years, using an emissivity of 0.5 reduced the largest total forcing decrease (reflected plus absorbed) to about minus one W/m2, rather than the approximately minus 1.75 W/m2 as shown after the eruption in Figure 3.

Data: One of the bad things about this is that the dataset is so short. Can’t be helped, because as far as I know there’s no hemispheric estimate of the albedo during the time of the previous eruption, El Chichon in 1982. (If you know of such a dataset, please post a link). But the good side of short data is there’s not much of it, so it’s easy to move around … for example, I’ve been looking at one-minute radiation measurements from Mauna Loa, 31 million data points per year since 1980. That’s hard to download, and too big for me to put up on something like photobucket.

But here we only have 14 years at 12 months per year = 168 records, so it’s small enough to put into an Excel spreadsheet, which I’ve done in .csv format here. The spreadsheet contains the TOA solar values, the albedo values, the Sato forcing values, the stratospheric temperature values, and as a special bonus, the hadCRUT4 records for the period both globally and for individual hemispheres. Enjoy.

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Joel O'Bryan

” Instead, I say that although initially the temperature responds to the forcings, soon the climate system responds to the resulting changes in temperature by changing the forcings themselves, often in very non-linear ways. “

Willis,
You know the word. I know the word. Most commenters here know the word.
I searched your post for it, it wasn’t there.
The word is feedback.
The feedbacks in our global climate system are robust, in the engineering sense, and strongly negative to forcings. You discuss them with your recent and this post’s quite lucid descriptions of (Lindzen’s) Iris hypothesis from the satellite data on cloud albedo.
If it weren’t for today’s corrupt climate pseudoscience and their national academy abettors, you should get a invite to the national academy for your solid work.
Back to the point at hand. Perturbations initially move the equilibrium, but feedbacks damp them out and then homeostasis mechanisms (water, in all its forms) moves the system back to where it was, as long as the the thing that is outside the system (solar energy input) doesn’t change (which of course it does too, which is why unchanging climate is an illusion.).
It is the implementation of that word (feedback) that the multi-billion dollar GCM ensembles purposefully get so, so, so wrong in order to provide their “politically useful” output for politicaians and crony capitalists looking to cash-in on the green subsidy windfall at the taxpayer and electricity users expense, while keeping the 3rd World energy starved.

Willis Eschenbach

Joel O’Bryan July 29, 2015 at 9:36 pm

Willis,
You know the word. I know the word. Most commenters here know the word.
I searched your post for it, it wasn’t there.
The word is feedback.

Thanks, Joel. The word is not there for a reason … because what is going on is NOT best described as a simple “feedback” of the type described by the IPCC.
For example, consider a field in an arid, hot region of the country. At some point in the afternoon, a critical temperature threshold is passed at some specific location in the field, and a “dust devil” forms there. The dust devil rapidly removes the heat from the surface in just that hot spot, and then once the heat is removed, the dust devil fades away and disappears.
Now you can call that progression of events, of the birth, life, and death of a dust devil, a “feedback” if you wish, and I can’t stop you … but wouldn’t you agree that is an incredibly feeble word to describe the an automatically appearing surface cooling phenomenon that only materializes when and where it is needed???
I mean, if you could invent a vacuum cleaner that would automatically materialize wherever my floor had extra dirt, suck up the mess until the floor was clean, and then vanish when the job was done, would you exclaim “Hey! I just invented a new kind of feedback!”???
Well, that’s what a dust devil or a thunderstorm is doing … and that’s not a feedback on my planet. That’s a different kind of animal entirely, requiring a different type of understanding and a different type of analysis.
See my post called “It’s Not About Feedback” …
All the best,
w.
PS—you might also enjoy my post “The Details Are In The Devil“, on the same topic …

Joel O'Bryan

The earth’s climate is not an open system. It is a closed system (for the most part, save solar wind stripping off hydrogen nuclei at the mesosphere). There is an input: solar radiation to the “top of the troposphere” is maximum at 5778 K at solar noon, and 3 K at midnight at the equator, and seasonal-dependent at the poles (the poles are certainly the radiators, and the equator is the collector).

” but wouldn’t you agree that is an incredibly feeble word to describe the an automatically appearing surface cooling phenomenon that only materializes when and where it is needed???

Not at all. Feedbacks appear (such as a strong tropical typhoon/hurricane pumping many thousands of A-bomb’s of heat to the 4K cosmic background) and then are gone, poof!
El Ninos come, they redistribute the west Pacific Ocean surface heat eastward, and then predictably become La Ninas several seasons later as they recharge the cooler waters.
Feedbacks beget oscillations. Simple EE circuits 101. RCL loops, on steroids.

If not feedback then what do you call it? Homeostasis? Something more…As Talkbloke commented on your ‘It’s not about Feedback’ Willis, “you and James Lovelock are a lot closer together in your ideas than you realize.” This looks very much like Gaia hypothesis circa 1975-8. I would be interested whether you agree.

I used to have a vacuum cleaner like that. He was called my Steward and was a very small Singaporean gentleman.

When there is an unbalance in energy it starts to flow. Entropy?

Willis
I have commented several times on your volcano posts and have written on them extensively elsewhere.
The big problem I have is that when, for example, the cooling effects of a large volcano is ‘proven’ and examples are given-such as Dr Mann’s belief that the 1257 Volcano helped to precipitate the LIA and Millers belief in the same theory, albeit by a group of volcanos 40 years later- the proof is not given in the wider historical context.
The 1257 volcano is a good example of only looking at what happened afterwards and not examining the context in as much the climate had already substantially deteriorated some 10 years prior to the eruption and returned to ‘normal’ very soon after.
Similarly, the late 1200’s volcanic effect was short term with some of the following decades being some of the warmest in the observational record.
If the volcano is sufficiently dirty enough/in the right place etc it can undoubtedly have a short term effect- a season or so. However, with most examples the lasting effect claimed is impossible to discern from actual real world observations.
tonyb

Mike

Firstly Willis, this is one of your best articles on this subject so far. The cumulative average ( a better term than running average which means something else ) is very informative It points out that a major volcano should produce a _permanent_ cooling not a temporary dip.
Now there are two reasons which could explain why this does not happen:
1) Another independent warming forcing gradually rubs out the cumulative cooling of the volcanic forcing.
2) The system displays a negative feedback
3) A combination of the above.
Option 1 is AGW , by arbitrarily selecting the appropriate “effective” scaling or sensitivity for each phenomenon they can be made balance over some given period. This is what IPCC does. It will work for the period for which the fiddle factors been tuned to work and will fail for a period where one or the other disappears: eg. post 2000 lack of eruptions.
Zealots will attribute any deviations as random “internal variations” of climate, or “correct” the data record to fit a failed hypothesis. An objective scientist will look at the detail of the deviations for further information as to whether the assumptions are correct and if not in what way they are wrong.
In short the slow rise of CO2 cannot account for the recover in a couple of years as is clearly seen in the data. It’s a con. At this stage it is nothing less than deliberate misdirection.
Option 2 is what an engineer will see, with the possibility of option 3.
Each individual event : clouds, dust-devils, whatever you like, is a complex, non-linear event that can not be simply described as a feedback. The regional sum of such events very likely can. We can then discuss whether it is a linear feedback or a stronger, non-linear feedback or whether non-linear but approximately linear over a limited range of certain variables.
You really need to make peace with the term feedback. This is very clearly what you are describing.
.

Conclusions: The main conclusion that I draw from this is that the central paradigm of modern climate science is wrong—temperature does not slavishly follow the forcings.

I think this post shows that they do follow the volcanic forcing quite closely but that there are strong negative feedbacks that correct the effects of the change in forcing within 2 or 3 years. This is evidence of much stronger negative feedbacks than are currently proposed by published climatology. This is the same as say much lesser climate sensitivity to ALL radiative forcings.
And that finally is why volcanic forcings get scaled down from the objective values that Lacis, Sato and Hansen produced in 1993.
More detail of the evaluation and history of volcanic forcing here:
https://climategrog.wordpress.com/2015/01/17/on-determination-of-tropical-feedbacks/
As I final note on this excellent article: don’t get too focussed on tropical feedbacks to extent of ignoring extra tropical regions. IMO the feedbacks are less strong once away from the tropical feedbacks you have done so much to explain. The tropics have a stabilising effect on the whole climate and are where the action is radiative forcing does have more effect outside this zone.

jhborn

Although I see no value in entering the nomenclature debate, I will commend to readers’ attention Roy Spencer’s Pinatubo analysis, which for my money is among the most readable treatments of the “feedback” view.

Mike

To clarify the thing about “slavishly following”. :
The IPCC idea is that there will be a new equilibrium point with at δT proportional to δRad. It should take decades to reach the new stable level. What this post demonstrates, is that the feedbacks are much stronger than accepted values, sensitivity is much less and the settling time is much faster.
A simple linear feedback approximation is compatible with all of that and would also imply a δT that is so small as to be undetectable with the data available. So I would conclude that temp is “slavishly following” forcings but is finally settling to an unmeasurable small deviation.
I don’t see anything here that is contrary to idea of simple linear climate response to forcing, it is just the sensitivities that are not consistent with the data. And that is what all the shouting is about.

jhborn

By the end of 1993, the observed post-eruption average forcing has returned to pre-eruption values … while the Sato theoretical forcing is still at minus two W/m2.

That’s where the nomenclature difference between the head post and Dr. Spencer’s above-mentioned post stands out. It is only the head post’s “Sato theoretical forcing” that Dr. Spencer refers to as feedback. The other “forcing” is, I believe, what he refers to as forcing plus feedback.

Mike

Joel, I think the “Sato’s theoretical forcing” is also forcing for Spencer. ( I question the scaling, which Hansen explicitly states was altered from their earlier values in an attempt to reconcile model outputs with the climate record ).
It is Willis’ ” observed post-eruption average forcing ” that is forcing plus feedback for Spencer and just about anyone else with an engineering background.
The article I linked above is a development of Spencer’s article but uses more recent data as well. Spencer’s graphs are very short and only used 72d averages which meant very few points. It was however, an inspirational approach.

ferdberple

much the climate had already substantially deteriorated some 10 years prior to the eruption and returned to ‘normal’ very soon after.
===============
Willis found this in a previous article. Global temperature anticipated volcanic eruptions, which throws cause and effect into question. In effect, global cooling causes volcanoes.

K. Kilty

Willis,
In response to Joel O’Bryan you state that what is going on here is not “simple feedback” as the IPCC defines it. I do not know the IPCC definition, and as you have referred to this definition, you might clarify quickly what this definition is to aid the occasional visitor here like me. However, I sense a disagreement over the word “feedback” at heart of this post and see no reason for it. The Spencer post that Joe Born refers to is a nice supplement to this post of yours, and Spencer refers to this as “feedback”.
Let me suggest an analogy. Even in a system as simple as the home furnace, one has a device that provides heat when needed (materializes) and then shuts off (vanishes)–sort of like your dust devil analogy. With separate zones it even appears where needed and then disappears. All of this works through feedback provided by the wall thermostat. And if the thermostat is of the “on/off” variety the feedback is not a linear system, but rather the actuator (furnace) is either off or saturated–pretty non-linear and a lot like your illustrative dust devil. No one is going to deny this as an example of feedback control, however.
How does seeing this as not “feedback” but some other sort of complex interaction advance understanding of the phenomenon?
Kevin

No, what Joel wrote is exactly right. “Feedback” is the precise term of art, and, as you say about the word “forcing,” it is useless to complain about it.
Your real complaint is that it’s not linear feedback. Which is right.
Overshoot and even ringing (multiple cycles of alternating overshoot and undershoot) are common in systems with feedback, particularly when there’s a significant delay in the feedback loop. That is true even when the system has only linear feedback, as in this example (showing step-forcings):
http://i.stack.imgur.com/1HIa6.gif
However, if the feedback is linear and the response to the forcing is followed by overshoot, then the duration of the overshoot will not exceed the duration of the original excursion caused by the forcing.
That’s not what your graphs show, not even close. In your graphs, the overshoot drags on and on, lasting for much longer than the original excursion caused by the forcing. That is evidence of nonlinear feedback.
Actually, there are multiple plausible explanations (and they’re not mutually exclusive). One explanation is that the feedback is highly nonlinear: it is stronger and/or quicker responding to negative excursions than positive. You identified powerful evidence for that in your wonderful “Albedic Meanderings” article.
Another possibility is that the feedback source (or one of the sources of feedback) is not radiative flux, but some other factor, such as cloud seeding, which has different duration and/or delay characteristics than radiative flux.
Another possibility is that, as Mike suggested, some other, unidentified factor is at work, perhaps just coincidentally, which is holding the radiative flux high, in the years following the volcanic forcing.

berniel wrote, “…then what do you call it? Homeostasis? Something more… This looks very much like Gaia hypothesis…”
Or Intelligent Design.

Howdy Willis,
I know perfection for you isn’t enough, so, your 2nd para. after 3rd figure, line 4 you are missing what I think is the word “forcing”. Don’t want to leave ’em guessing.
“Also, the speed of the climate response is visible in Figure 3. The total forcing (yellow line) follows the Sato forcing estimate (black line) for the first four months or so after the eruption. But after that, while the Sato calculated forcing continues to become more and more negative, the observations show that the does not ever become much more negative than it was at four months after the eruption. Instead, it runs level for about a year, and then rapidly increases. By the end of 1993, the observed post-eruption average forcing has returned to pre-eruption values … while the…”

Willis, sorry. Make that line 5

WilliMac

[dust devil] Is a tornado similar, just more powerful?

george e. smith

“””””….. (the poles are certainly the radiators, and the equator is the collector). …..”””””
One thing that the earth’s polar regions are not, is ” the radiators “.
That is the very last thing that they are.
The total radiant emittance of a black body at the Temperature of the coldest polar regions (Antarctic highlands; circa -94 deg. C) is around one twelfth of the total radiant emittance of a black body at the temperature of the hottest tropical desert surfaces (circa +60 deg. C or higher).
The earth’s tropics radiate at about 1.8-2.0 times the global mean radiant emittance, while the coldest polar regions radiate at about one sixth of the global mean rate.
g

Joel: UNEP, UNFCCC, IPCC etc.. Are all based on the idea to use nature to dominate Man and undermine the Western World cultural and economic values. I think we can just call it cultural Marxism? A product of communist Soviet is now loose in the Western World. And it’s probably a bit absurd for today’s Russia and China to witness the 68’s attempt to revive Marxism in the Western World, less than 30 years after it failed in Soviet and China. China started to work when they implemented capitalism. And the Western World will stop working if capitalism is banned.

+10
Willis’ posts are always very interesting.

george e. smith

“””””….. The IPCC defines “radiative forcing” as follows:

Radiative forcing is the change in the net, downward minus upward, radiative flux (expressed in W m–2) at the tropopause or top of atmosphere due to a change in an external driver of climate change, such as, for example, a change in the concentration of carbon dioxide or the output of the Sun.
for example aerosol or greenhouse gas changes in paleoclimates. …..”””””
Now let me see if I have this straight.
“”””” The IPCC defines “radiative forcing” as follows: “”””
The rest is what you posted, as an IPCC definition.
So the IPCC said this as part of a scientific definition : “”””” Sometimes internal drivers are still treated as forcings even though they result from the alteration in climate, for example aerosol or greenhouse gas changes in paleoclimates. “””””
I’m flabbergasted; One can actually use the word ” sometimes ” in a rigorous scientific definition ??
That sentence reads to me as gobbledegook anyhow !
“” Sometimes internal drivers are still treated as forcings even though they result from the alteration in climate, ….””
I thought ” Forcings ” were supposed to be the DRIVERS of climate; but now it seems climate can make its own forcings ??
I don’t know where you found this IPCC definition of ” forcings ” Willis, but it sure is a bobby dazzler .
g

Danny Thomas

Willis,
Not completely off topic, but more or less a tangent. What are your thoughts w/r/t volcanic/geothermal activity in the area of the western Antarctic? (Know volcanoes have been an area of focus of yours). Asking as I see that as a good portion of what needs to be evaluated/discussed w/r/t those ice sheets and their activity IO perceive volcanoes are a bit understated regionally. Hansen’s recent offering indicates great concern, but this observers perception is the volcanic/geothermal involvement is not well evaluated/understood. (Apologies for the tangental comment).
Respectfully,

Willis Eschenbach

Danny Thomas July 29, 2015 at 9:36 pm Edit

… I see [Antarctic volcanoes] as a good portion of what needs to be evaluated/discussed w/r/t those ice sheets and their activity IO perceive volcanoes are a bit understated regionally.

Thanks for the question, Danny. I doubt that the sensible heat in the volcanoes in general makes a whole lot of difference to the larger world for a couple of reasons. First, it’s not a lot of heat. I mean, people in Hawaii just go on living within a hundred feet of an active lava flow … Second, the world is big, really big, and volcanoes are point sources. Other than perhaps in isolated “hot spots”, volcanoes are just not dense enough to affect large areas.
Now, having said that, if there is significant geothermal heat directly under an ice cap, you’d get a curious situation, because then you’re not talking about volcanoes or eruptions or lava flows. You’re talking about heat just seeping through the rocks. I would suspect that such geothermal heat would be pretty constant, not changing much with the seasons or the years. It would make the rock/ice interface slipperier than without the heat … although I understand that there is almost always a thin layer of water between the ice and the rock even without geothermal heat.
All good questions, no clear answers … it’s climate science.
w.

Danny Thomas

Thank you!

Yes, and here’s an interesting, relevant article: Subglacial volcanoes melting West Antarctic Ice sheet, say scientists.

Danny Thomas

Dave Burton,
Thank you. I’ve been reading up on this phenomena and all I can find and it’s interesting that the volcanoes are a ‘relatively recent’ discovery, and yet as Willis suggests even though we’ve not known about their extent why would we tend to think they’re leading to melting now as they obviously been there much longer than we’ve been aware.
Antarctica is a mystery (to me and apparently many, many others). The geothermal portion of the conversation is one of the unknowns which we just don’t have an understanding. Appreciate the article.

Dixon

I saw an ocean surface temp plot recently (which I need to check out again) and most of the warming areas were based around what my limited geology says are subduction zones. Given how cold the deep oceans are, how small the warming trends in ocean temp are, how poorly surveyed most ocean floor is, much less sampled, how the earth seems to run using coupled oscillating systems and how volcanic activity seems quite periodic, I do wonder if we’ve underestimated the impact of geothermal heat on ocean circulation and hence climate. As you say, too many questions.
But it doesn’t matter does it? The answer is renewables whatever the cost! / sarc off.

dp

If there is no trend in volcano eruptions then there is no trend in any volcano forcings. Sure there is a weather response to individual eruptions but they are not long term and don’t matter in the big climate picture. If Mt. Rainier, heaven forbid, should explode like Mt. St Helens it results in a spike and nothing more. They are anomalies. Any use of non-trending volcano forcing is fraudulent when applied to climate. It’s really that simple. In any event we can’t manage volcanoes and have to accept what ever they dish out with the understanding that they don’t affect climate except in the short term. Unless we’re talking about a new version of the Deccan Traps or equivalent.

Joel O'Bryan

Volcanic aerosols are the climate modelers’ (savior) fall-guy right now. They have to artifically pump-up aerosols in the models to counterbalance their (circular) logic of the CO2 forcings to arrive at today’s temps from yesterday’s starting point (Mr Pause, please take a bow).

george e. smith

I thought aerosols were now known to be the product of plankton farts.

Joel O'Bryan

dp,
The whole volcano sulphur-particulate aerosol thing, today absent a Deccan Traps event, is just what the modellers curently use to save themselves from reality. They must invoke higher than observed aerosols to save the models from running too warm due to their (circular logic) tuned-to-be too warm state.

Graeme W

Conclusions: The main conclusion that I draw from this is that the central paradigm of modern climate science is wrong—temperature does not slavishly follow the forcings.
To the contrary, when the tropical temperature changes, the solar forcing subsequently changes in the opposite direction, negating much of the effect of the volcanoes.

Only being pedantic because I think you’re right, but that conclusion doesn’t follow from the investigation presented. What you’ve shown in that the forcing themselves can react to other forcings, so a change in one forcing doesn’t mean a corresponding change in total forcing — other forcings can change in response, such as the solar forcing changing in response to the aerosol forcing change.

george e. smith

Lenz’s law an the like, are examples of le Chatelier’s principle’ that changes in physical systems induce other changes that end up opposing the original change.
For example, LEDs that emit photons, some of which can escape to be seen by us, commonly tap most of those photons (TIR trapping) due to the high refractive index of LED materials. As a result many of those trapped photons rattle around inside the diode, and can get re-absorbed by the diode, since good LEDs are also good photo-detectors, and conveniently can efficiently absorb the very same photons they emit.
These re-absorbed photons generate a photocurrent, which it turns out flows in exactly the opposite direction to the current being applied to the LED from its external driver circuit,, so the net current drops for the same diode voltage, creating an apparent increase in the internal impedance of the diode.
Well it isn’t an apparent increase, it is a real increase in the impedance, and it acts to reduce the external radiation from the LED.
If you change the optical geometry of the LED die, so as to eliminate some of the TIR tapping, you get les captive photons, and so generate less reverse photo current, so the diode voltage drops, and its power efficiency increases.
Soraa is an LED company founded by Shuji Nakamura; inventor of the blue LED and blue laser diode; and they grow their LED materials on single crystal GaN which is a hexagonal crystal (Wurzite lattice I believe) rather than the cubic diamond lattice of silicon or GaAs.
So Soraa saws their LED dies into an equi-lateral triangle shape, rather than a square or rectangular shape. This triangular die has much lower TIR trapping, and shorter photon path lengths before escape from the die, giving them the most efficient blue LED you can get.
So any and all physical, chemical or biologic processes that contribute to any and all climate processes, is individually and collectively subject to le Chatelier’s principle.
I wouldn’t call that ” feedback “, it is simply ” compensation “.
g

george e. smith

And the typos are a consequence of a lousy keyboard (or technique) , and not the result of amateur ignorance.
g

upcountrywater

Farce-ing…The planet going to burn-up due to AGW..

Speculative drivel once again. Volcanic ash simply means more sunlight being absorbed in the atmosphere and less being absorbed at the surface. Laws of thermodynamics dictate the change in temperature gradient this would cause and the time taken to cause it, but “radiative forcing” is nothing other than a misleading idea that masks the fundamental properties of the atmosphere, which are a function of incoming energy, atmospheric mass and gravity.

Joel O'Bryan

If I put a mirror on a laser beam input, that would otherwise rapidly warm a surface, would you still think that the surface must somehow magically warm? Of course not. Aerosols are a mirror to Shortwave solar radiation.
In our climate, that mirror is volcanic sulphur dioxides reflecting shortwave (SW) back to outter-space. But volcanic aerosols are removed within a year or two by weather, water, and gravity for one-off events like Mt Pinatubo. Only the multi-millenial-long scale events like the Deccan Traps have the staying power to reduce solar SW inputs.

Stephen Richards

If you really know this post is rubbish write one of your own to show where and why otherwise FO

Khwarizmi

wickedwenchfan “…but “radiative forcing” is nothing other than a misleading idea that masks the fundamental properties of the atmosphere, which are a function of incoming energy, atmospheric mass and gravity.”
==========
Even if you were only interested in temperature you couldn’t derive any fundamental “properties” of the atmosphere from your three factors. With no outgoing energy budget, your model guarantees permanent global warming, even beyond the life of the sun! It also has no water to absorb, emit or reflect radiation, moderating temperature extremes that would otherwise occur from night to day.
In other words, your model is just “speculative drivel.”

Richard M

@wickedwenchfan
I think you are being a little too simplistic in your thinking. I suspect that the real answer is a combination of what you are getting at and the natural feedback system.
For example, if what Willis is stating was the entire picture then there would be no such thing as ice ages. The climate system would adjust to any increased albedo and allow in more solar energy preventing the accumulation of ice. On the flip side, your view would allow massive swings in the climate system from volcanoes, etc.
I suspect the real answer incorporates both ideas to some degree.

wickedwenchfan wrote, “Speculative drivel…”
Oh, good grief: more “slayer” nonsense. Sometimes it seems like the slayers’ raison d’être is to serve as straw men for climate alarmists to ridicule.
Willis and I occasionally disagree, but he never writes “drivel.” As Joel points out, it is ridiculous to suggest that changes in radiative flux can’t affect surface temperatures.

george e. smith

Well any thing or every thing that results in “absorption” (rather than reflection or scattering) by the atmosphere, results is solar energy that does not reach the earth condensed surface (particularly the deep oceans, and contribute to earth’s energy budget.
Instead, it is eventually converted to isotropic LWIR emissions from the atmosphere, and less than half of that LWIR radiation is able to reach the surface; the rest escapes to space. The second law suggests that the net ” HEAT energy ” flow in the atmosphere must be from the hotter surface towards the colder space. So warming the atmosphere, is not the same as warming the surface.
So anything which absorbs solar spectrum energy in the atmosphere, by any means, results in a net cooling of the planet, rather than a net warming.
g

Bob Highland

Beautifully argued and presented logic as always, Willis. The more one looks at it, the better one realises that the remarkable thing about Earth’s climate is not that it changes slightly through various cycles and events, but how stable it is over time. This suggests that there are some powerful stabilising factors in the whole system that react to perturbations to restore comparative stasis, and I agree with your overall central premise that it is the tropics and the hydrological cycle that are the key.
After all, the tropics/sub-tropics are the principal driver of heat flows across the planet, since those latitudes receive the most heat and rainfall and affect the balances elsewhere. The high latitudes don’t get enough heat over a year to be worth a damn, and while the mid-latitudes do receive an appreciable amount of heat, the actual weather/temperature that they experience is more often a factor of which way the wind is blowing than the heat actually downwelling in any given location.
Another clue is that on a typical day in the tropics it gets to about 32C, day in, day out, around the world. I am sure that it is no coincidence that that is also the typical maximum temperature of seawater. Beyond that temperature, water evaporates off the moist land/sea surface at a rate that determines what happens next by way of clouds, storms etc, and these phenomena are what drive the atmosphere and ocean currents into systems that affect the rest of the world and modify their weather, either hotter or colder than their local insolation might suggest on any given day.
It is to be regretted that a certain section (sect?) of the populace has chosen to become obsessed with CO2, attributing it with a power far beyond its modest radiative means, when water, with its ubiquity, concentration, high radiative activity, massive specific heat and high latent heat properties, and its quad-state (solid, liquid, vapour and suspended droplet) existence marks it as the true driver and equilibriant of climatic systems.

charles nelson

I agree with what you say.
I believe that the major problem for Climate Science is that the most potent “Warming Gas”; Water Vapour is also a ”Cooling Gas”.
There is no ‘Greenhouse’ with its implicit finite/absolute barrier, instead there is an infinitely fluid and variable blanket which handles the transfer of ‘energy’ in and out of the atmosphere on a: topographical, continental, oceanic, seasonal and diurnal basis.
Just one example, the University of Wisconsin has some marvellous satellite animations which allow you to see atmospheric conditions over the Pacific Ocean infra red, water vapour etc.
No Engineer could look at these images of the actual atmosphere shunting heat around the planet and think for a split second that there’s even a hint of overload. Talk about excess capacity!..the Atmosphere isn’t even ticking over let alone stressed. This preposterous notion that heat his ‘hiding’ in the oceans makes my blood boil… If the oceans need to eject heat they can do it any damned time they like….yet there are vast swathes of this planet where there is barely any water vapour present at all!
As for the simplistic atmospheric models that are used, people have no idea of the complexity and variability of the atmosphere. A few years back I tracked a body of warm air as it built in the eastern Pacific, crossed central America and Cuba making a beeline for the Arctic. Water vapour from the equator became part of the Greenland icecap entire process took around 3 days…now that’s impressive!
The more the ‘scientists’ get bogged down in 100th˚C arguments the more obvious it becomes that few of them could be trusted to set the climate controls of a large building let alone an entire Planet!

“…the climate system has proven to be surprisingly insensitive to such variations in forcing”.
In the short term quite possibly.
However longer term-where there is tens to hundreds to thousands to tens of thousands of years of increased volcanic activity- the system might not be able to respond in such a manner.
So the eruption of major volcanic provinces such as the Siberian Traps seems linked to mass extinctions and hothouse conditions.

Another Ian

Willis
Re your response to Joel above and the mention of dust devils – somewhat O/T
“ROM
July 28, 2015 at 8:21 am · Reply
Yeh! The amount of gas aka “air” in those thermals make the amount of gaseous CO2 they are trying to capture look like piddling in a lake.
Say a thermal is 300 metres across;
Thats an area of about 71,000 sq metres
Thermal height from Ground to inversion or cloud base ; say 2500 metres [ 8000 ft ]
Air weighs in at sea level and standard temperature and pressures at 1.1 kgs / cubic meter so say with the decreased density at altitude , about 1 kg / cu mtr
Weight of air in a typical Australian summer thermal , very, very roughly 1.75 million tonnes all moving upwards at anything from 2 metres / sec [ 400 FPM ] to 8 mtrs / sec [ 1600 FPM ]
And you have something like that every 2 or 3 or 4 kms as you can see when those cumulus clouds dot the sky. Each one of which was created by the water vapour in that thermal column condensing out when it runs into the colder levels of the atmosphere at height.
Similar in effect when you breathe out on a frosty morning and your breath turns into a thin fog from the water vapour in your breath condensing when it reaches the cold dry frosty outside air .
ALL clouds as in ALL clouds other than the 80 to 100 km high Arctic and Antarctic Noctilucent Clouds are formed by rising air.
Of course there are many, many other days where the air is dry enough so that no clouds or few clouds form on the top of thermal columns and we have clear air thermals.
Where air goes up, air also comes down but usually spread over a much wider area and therefore slower in descent than in a thermal column.
But if you run into a good patch of “sink” the altimeter unwinds like the backward running second hand of a clock which definitely gets ones attention as the ground starts to loom up.
A regular, nice round classical thermal column is like global warming, it exists in theory but most glider pilots have yet to find one as thermals are messy, shifting, changing, more often petulant than not and makes one wonder why the hell one ever took this frustrating sport up
A really rough thermal, one that jars your teeth literally like getting mixed up in a good willy, willy thats more like the inside of a concrete mixer as you try to climb away from a low level definitely shakes your confidence in your immortality.
Thats until you hit a beauty and get a lift like ride at 1200 feet or more a minute up to 10,000 feet and you are on your way with a smile on the face and the wind in your hair, thats figuratively speaking only in these days of fully enclosed cockpits.
From
http://joannenova.com.au/2015/07/wait-til-you-see-these-numbers-on-carbon-capture-and-storage/

I am impressed, and pleased to see the term ‘forcing’ get some critical review. I suspect it caught on because the codewriters for GCMs could use it to claim they were modelling everything but the kitchen sink in their bloated, but still utterly inadequate to the claims being built upon them, models. Just calculate, estimate, or merely assert a forcing for item X, and lo and behold with a modest amount of keyboard time, you have X included in your model. Later on, flux adjustments, or whatever the modern perhaps more hidden version is, will take care of the verisimilitude issues so important to those who have claims in mind for political goals.

I agree that feedback is the wrong word. A feedback is that a function of the output is being put back into the system, and I would argue that the system is far too complicated to describe as just inputs and outputs.
It’s le chatelier’s principle at work: a system (at equilibrium) will react to oppose any change made to it. We can probably consider parts of the system to be close enough to equilibrium to still be valid in this case. A nice sunny day is definitely closer to equilibrium than when it has a giant ash cloud being pumped into it.

ulriclyons

“The form of the climate reaction will be an albedo reduction due to the temperature reduction, which will cause an increase in available solar energy.”
What about ENSO? Interestingly, the El Nino episode from mid 1991 to mid 1992 is largely during positive NAO/AO conditions.

EternalOptimist

Feedback is definitely the wrong word. Willis is describing a complex reactive system as opposed to a complex system. Both can contain feedbacks

steveta_uk

Hmmmm – if not feedback, what would you call such a process? Perhaps it is behaving more like a governor – come to think of it, I think someone may ave suggested this before.

John M. Ware

Fine and enjoyable article. One little thing: under Fig 3, paragraph 2, end of line 4, word or words missing: ” . . . that the [blattablattablatta] does not . . . “

Leo Smith

well as an engineer I would say that feedback is exactly the right word. A complex form of feedback, yes, but that’s still feedback.

ulriclyons

I see ENSO and the AMO as amplified negative feedbacks.

Bloke down the pub

Typo? ‘ Sato calculated forcing continues to become more and more negative, the observations show that the …..does not ever become much more negative ‘
Is there a cloud seeding effect somewhere here that is not being taken into account?
By the way, if the net forcing of volcanoes is positive, does that make their absence in C21st another cause for the pause?

jhborn

the observations show that the does not ever become much more negative than it was at four months after the eruption

A missing word?

K. Kilty

Yes.

Mike

Joel:

The whole volcano sulphur-particulate aerosol thing, today absent a Deccan Traps event, is just what the modellers curently use to save themselves from reality. They must invoke higher than observed aerosols to save the models from running too warm due to their (circular logic) tuned-to-be too warm state.

I think the level of “atmospheric optical density” from volcanic aerosols is reasonably well measured. The fiddle factors arise in working out the forcing which comes down to guessing ( or using convenient values ) of aerosol size distributions to derive the radiative ‘forcing’.
These have been tuned to make the models roughly match 1960-2000 climate record.
Several refs and quations on that subject here:
https://climategrog.wordpress.com/2015/01/17/on-determination-of-tropical-feedbacks/
Hansen et al 2002

3.3. Model Sensitivity
The bottom line is that, although there has been some
narrowing of the range of climate sensitivities that emerge
from realistic models [Del Genio and Wolf, 2000], models
still can be made to yield a wide range of sensitivities by
altering model parameterizations.

RERT

Willis –
Why did you stop the charts of your analysis at 1998? Is the subsequent data unavailable, or was there some other reason?
R.

Mike

Willis’ fig 2 confirms what was pointed out here:
https://climategrog.wordpress.com/?attachment_id=902
that major eruption have a long term effect on the composition of the stratosphere.
I would describe Willis’ violet line as the sum of volcanic forcing and climate feedback to volcanic disturbance of surface temps.
His gold line is probably a secondary effect of volcanoes, rather than a direct feedback. It is a consequence of directly induced changes in the stratospheric chemical composition, not a feedback of what is happening in the lower climate.
This warming forcing produced by volcanoes which so far seems to be conveniently ignore by mainstream climatology and is falsely attributed to AGW.
Which better explains the observed data can be seen in the post 2000 period with AGW getting ever strong and satellite observations showing slight cooling.

Mike

Forgot the image:
“Why Volcanoes Don’t Matter Much” , well if that is meant to mean that there is a very low sensitivity to initial volcanic forcing, I would agree.
However, I would say that analyses such as Willis presents here and the effects on the stratosphere matter a whole lot. They provide the key to understanding the different effects, sensitivities and causes. Saying they “don’t matter” would be foolish.

stevefitzpatrick

Willis,
Very interesting article. I particularly like the conversion of satellite measured stratospheric temperature change to a change in net solar absorption via Stefan-Boltzmann…. very clever. I would only suggest that while the development of reflective clouds probably does have a strong cooling effect (a strong negative feedback) in the tropics, the situation outside the tropics could be different. An increase in cloud cover at high latitudes in winter likely reduces radiative cooling of the surface…. since there is much less sunlight to reflect. Changes in clear sky moisture for sure change the rate of radiative loss (I have confirmed this with a radiometer), so increasing moisture level could be a positive feedback with a clear sky. The influence of clouds on reflected solar energy may well be why the tropics have warmed the least. Positive feedbacks may well be why high northern latitudes have warmed the most.
There are positive and negative feedbacks which are both acting in response to temperature changes. How large these feedbacks are, where and when they are important, and what their opposing effects sum to are clearly difficult to determine. Simple energy balance calculations (like Nic Lewis and others have done), indicate a slightly positive net feedback on average. I applaud your efforts, but hope you will also consider feedbacks outside the tropics.

george e. smith

“””””….. Positive feedbacks may well be why high northern latitudes have warmed the most. …..”””””
Not so.
Tropical regions are hotter than polar regions; excuse me; I meant MUCH hotter.
Thermal (BB like) radiation goes as the 4th power of Temperature, and the thermal spectral peak spectral radiance increases as the 5th power of the temperature.
Ergo, the greatest thermal radiative cooling (by far) of the earth, occurs in the very hottest tropical deserts, and other tropical environments. The total radiant emissivity in the tropics, can be a factor of 12 times higher that the total radiant emittance of the Antarctic highlands.
So the reason the poles warm faster than the tropics, is because the tropics cool MUCH faster than the polar regions. It’s not even close. The polar regions are NOT cooling the earth. They would be even colder, and thus radiating even less, if it were not for the massive transport of heat from the tropics via the gulf stream and other ocean currents, as well as atmospheric circulation.
The polar regions are cold because not much solar flux ends up there, compared to in the tropics; and they warm faster, because they simply cannot cool, at their low Temperatures.

stevefitzpatrick

Are you suggesting that the average temperature of high latitude regions has increased less over the last 100 years than the average temperature in the tropics has increased? If so, you are simply mistaken.

eorge e. smith

“””””…..
stevefitzpatrick
July 30, 2015 at 5:45 pm
Are you suggesting that the average temperature of high latitude regions has increased less over the last 100 years than the average temperature in the tropics has increased? If so, you are simply mistaken. …..”””””
Steve I’m a little dense this morning; excuse me, make that a whole lot dense.
So help me out; please cut and paste the exact wording in my post that leads YOU to conclude that I ” suggested ” what you wrote above.
I could have sworn that what I wrote EXPLAINED exactly why the high latitudes have warmed more, than the tropics.
Simple translation:
A black body radiator at a Temperature of one kelvin, doesn’t radiate as copiously as a black body radiator at a Temperature of 300 kelvin.
So if you irradiate each of those BBs with an irradiance of 342 w/m^2 (or even just 1 W/m^2), the colder body will increase in Temperature much more than the hotter body does.
No I am NOT suggesting anything so obviously foolish, that even a 4-H club member knows is wrong.
g

eorge e. smith

“””””…..
george e. smith
July 30, 2015 at 1:04 pm
“””””….. Positive feedbacks may well be why high northern latitudes have warmed the most. …..”””””
Not so. …..”””””
English translation:
POSITIVE FEEDBACKS ……. are NOT why ….northern latitudes have warmed the most. …..”””””
QED

rgbatduke

Now, the current climate science paradigm says that regarding the things that affect temperature, everything averages out in the long run except for any changes in total forcing. The current paradigm further says that the future evolution of the climate can be forecast by the simple linear relationship given as:
Change in temperature equals climate sensitivity times change in total forcing.
Me, I think that’s simplistic nonsense

Me, I think that is a definition of climate sensitivity, which makes it really difficult for it to be wrong.
Remember, if you define forcing in terms of TOA radiation imbalance, a nonzero forcing must drive an internal energy change or the gods of energy conservation become angry. Since the gods of thermodynamics define temperature in terms of internal energy content, that too must change. The change will continue until TOA radiative imbalance is brought back to zero, and as long as the imbalances/changes are small it is reasonable to use a Taylor series and keep one term, a.k.a. “a linear model” for the net change that brings it back into balance (even if the way it returns is e.g. exponential or multiexponential decay to the new “equilibrium”.
This means that you can only really object to two things in the definition. One is the assumption of linearity in the shift, even for small shifts. Remember, this works both ways — it is equivalent to asking “Suppose the Earth were suddenly and uniformly heated by 1 C above its current instantaneous perfect radiative balance temperature. How would TOA forcing change?” Most people would say that it becomes net positive to lose the extra heat, by an amount proportional to the 1 C change relative to the base temperature, pure Taylor series. This is unsurprisingly exactly what you get from a Taylor series of SB around some initial equilibrium temperature, of course. The other is that the constant of proportionality is a constant of proportionality.
Of the two, personally I think the second is a worse assumption than the first, because the first is just math and a very reasonable way to define a linear response. The second, however, is obviously incorrect — the “sensitivity” is not a constant in space or in time. It isn’t even clear that its average is constant (assuming one figures out a clever way of defining the average of a moving target). We know this because we know that the mean temperature of the Earth is not a constant even when we don’t change the state of the sun. The Earth is clearly capable of making changes to its own “forcing”, because if one plots any of the temperature anomalies, they are not smooth curves but rather bounce up and down.
Which brings me back to fluctuation-dissipation, of course. Every time temperature changes, so does the forcing. Every time the forcing changes, so does the temperature. The way it responds in time both ways is a critical clue to how it loses the energy, but the only way I know of to ascertain a detailed knowledge of the dissipative modes that control the forcing is from TOA measurements of the specific spectral components that control net forcing.
Of course it would also be lovely to know how internal energy is moved around internal to the system, but it is simply impossible to measure that, and difficult even to meaningfully sample it, and trying to predict it involves solving the Navier-Stokes equations from the unknown initial conditions subject to equally unknown future conditions.
So if you want to assert that $\Delta T = \lambda \Delta F$ makes no sense at all from the tail chasing point of view where forcing both leads and follows temperature change as need be, I’m not sure I agree. But if you want to assert that in this expression, $\lambda(t,T,C_{co2},I...)$ (for a rather long list of variables, many of which are internal state variables, some of them integrated over past times) is not constant and not reducible to a single number that does not change independent of the concentration of CO2 or aerosols or temperature or humidity or orbital state or solar state or ocean state or…
You’ll get no argument from me. It isn’t clear that it can even be meaningfully averaged to make it into a pretend constant, or an effective constant. Because the climate isn’t stationary with or without any overt parametric shifts. It is a nonlinear, chaotic, turbulent, non-Markovian system, that is very likely highly multistable, with a different $\lambda$ associated with each climate attractor and a near-continuum of attractors (in a very high dimensional space). But hey, we’re still going to present it that way because yeah, the Earth still has to satisfy the first law and the zeroth law (or microscopic definitions of “temperature”).
rgb

Willis Eschenbach

Thanks for that, Robert, your contributions are always appreciated.
It’s not a question of the tail chasing the dog. It’s that in a system that has a thermostat, as it appears the earth does, there is no relationship between input and output.
Take a car under cruise control as a familiar example. What is the relationship between fuel consumption and speed? Well, in general there isn’t one … or as you put it much more clearly, I would agree with you that lambda, the climate sensitivity, is both :

“is not constant and not reducible to a single number that does not change independent of the concentration of CO2 or aerosols or temperature or humidity or orbital state or solar state or ocean state or …”

Gotta run, more interesting issues raised in your comment but I’m heading out soon …
More later,
w.

Rob Morrow

RGB,
“Remember, if you define forcing in terms of TOA radiation imbalance, a nonzero forcing must drive an internal energy change or the gods of energy conservation become angry.”
Willis’ article is suggesting that the duration of said TOA energy imbalance is shorter than the current paradigm suggests. During that shorter period of imbalance there is still an increase in energy storage. That smaller stored heat will still dance with the radiative imbalance until a new transient equilibrium is reached. I think if that dance is just one song instead of a marathon, it plays well for:
“Change in temperature equals climate sensitivity times change in total forcing.
Me, I think that’s simplistic nonsense”
Rob

Rob Morrow

Thinking now that I misunderstood and you are really just objecting to the often equivocal use of the word “forcing”.

rgbatduke

Oops, sorry about the accidental shouting
[Fixed, I think … w.]

Sturgis Hooper

In the post by Mike?

rgb,
Can’t see your original post. Did you use a naughty word like d*n*er and get sent to moderation? Looking forward to it when it shows up.
pbh

Sturgis Hooper

Or in comments to another post?

george e. smith

Where shouting ???
g

Greg in Houston

A bit off topic, but what this also seems to show is that the idea that “deadly” CFCs migrate to the southern hemisphere to affect the ozone layer.

Or maybe it’s the phytoplankton 😉
I suspect the CFC’s migrate south with the other snowbirds.
(Some great posts recently that require re-reads and note taking. Thanks to the writers.)

TImo Soren

For clarity: Willis is the ‘reaction of the system’ to the eruption solely the the cloud mechanism OR are you saying ‘I know the system reacts’ and I am looking for how my hypothesis: ‘that there is a reaction’ versus the Sato’s model and demonstrate my hypothesis ‘fits the data’ better than Sato’s?
The reason I ask, is I am not a big fan of the ‘my model fits the data better than yours’ but I am a big fan of the data imply some underlying concept that is evident in the analysis.
It seems to me that you are arguing that ‘the data supports a reactive self-adjusting system’ rather than the Sato model. Hence, we should investigate the fundmentals of what they ,say cumulus reaction to cooling in the tropics, are really doing what the set of reactions are.

ToA is 340 W/m2 +/- maybe 10. According to IPCC AR5 the additional RF due to the 120 ppm of CO2 added between 1750 and 2011 is about 2 W/m^2. The four models use 2.6, 4.5, 6.0 and 8.5 W/m^2 as the RF due to corresponding ppm of CO2. Trivial in comparison to 340.
The notion is that this additional RF is trapped in the atmosphere under a blanket, another half baked analogy as incomplete as the GHE. Both ignore the role of water/water vapor as master thermostat.
The RF of CO2 is lost in the ebb and flow, uncertainty and rounding errors of the total global power (watt is power, not energy) balance.
Geothermal heat flux through the ocean floor is a huge uncertainty.

george e. smith

TOA is 1362 Wm^-2 give or take maybe 4 Well that is average for the whole solar orbit period, and it has that value pretty much 24 hours a day. But it only illuminates a bit more than half te planet ata time.
At 340 Wm^-2, even continuously, even a perfect black body cannot reach a Temperature of 288 K, which is earth average, let alone reach 333K or more which some tropical desert surfaces reach or exceed every day in northern summers.
Earth is not a perfectly thermally conducting isothermal black, or even gray body, which it would have to be to be 59 deg. F everywhere at all times, in the Kevin Trenberth et al climate model .

The interesting aspect and semi-proof of Willis’ point is that Pinatubo, for example, had “forcing” of -4.0 W/m2 while the most temperature dropped was about -0.35C.
That forcing is almost as large as doubled CO2/GHGs yet the surface temperature barely moved. It is, in fact, hard to pick out from the normal internal variability.
So why does doubled CO2 produce 3.0C yet an equivalent change from a volcano produce -0.35C. It could be magic although I’m sure the climate change prophesy has an excuse/explanation.

Sturgis Hooper

As nearly as I can divine from the incantations of Warmunistas, they might murmur something about water vapor feedback. But even without that supposition, the assumed effect of CO2 alone is around one degree C, which still looks too high. This suggests net negative feedbacks, as in fact observed with volcanoes.

.35c is significant, no matter what time period it covers and that is just from one isolated volcanic eruption.
In addition it only had an explosive index level 6. Much less significant then say a 7 or 8.
What would happen if Yellowstone erupted for example?
According to Willis ,and his line of reasoning hardly anything.

the central paradigm of modern climate science is wrong—temperature does not slavishly follow the forcings.
================
Climate science ignores the most fundamental of principles. When subjected to a change, systems react to counter the change.

Volcanoes are important for replenishing atmospheric CO2 via subducted limestone (mostly) and fossil fuels. The current CO2 crash would have lasted for millions of years without Man burning fossil fuels. We would have had to wait for a period of massive volcanism and an end to the current ice age with the melting of Greenland and Antarctica (releasing CO2 from the oceans). That’s how the Carboniferous CO2 collapse ended, the only other time in earth’s history when CO2 levels have been so low.

rogerknights

‘The word “forcing” “farcing” is what is called a “term of art” in climate science.’

george e. smith

AKA as “jargon”.
g

Craig Loehle

Years ago I had a long-running debate with a colleague in Ecology who insisted that interactions in ecosystems were linear. He liked linear equations because then complex analyses of the whole system could be done, such as tracing dependencies and impacts. He wanted analytical expressions and because he wanted this he insisted that the real world had to match what he needed. I never made any headway even though we remained friendly. This situation is the same, the assumption that responses to forcings are a simple multiplicative relationship is to deny that negative feedbacks can exist. In science such an important thing should be determined empirically and rigorously and not just because it is a convenient simplification. Kudos to Willis for keeping on pushing his (correct IMO) theory.

Willis Eschenbach: “The increase in available energy will be of the same order of magnitude as the corresponding decrease due to volcanic aerosols.”
Nice work, Willis. That is precisely what explains the absence of volcanic cooling. They are all imaginary but are shown on various temperature curves. I demonstrated (“What Warmomhg?” pages 17-21) that all these so-called “volcanic cooling” incidents are nothing more than misidentified La Nina valleys. ENSO and the occurrence of volcanoes are not in phase. If by chance an eruption coincides with an El Nino peak it will be followed by a La Nina valley which invariably is named as this volcano’s cooling. An example is Pinatubo. You find it marked even on monthly satellite temperature charts. On the other hand, if the eruption coincides with a La Nina valley it will be followed by an El Nino peak and that volcano will not get any cooling to call its own. An example is El Chichon. Intermediate cases of various degrees of reduced cooling also exist because of the various possible mismatches between eruptions and ENSO phases. I have had it out for five years now but the climate “scientists” who control temperature records are still ignorant of this.

ulriclyons

How about large eruptions cause El Nino conditions/episodes,

feed·back ˈfēdˌbak/ noun
1. information about reactions to a product, a person’s performance of a task, etc., used as a basis for improvement.
synonyms: response, reaction, comments, criticism; More
2. the modification or control of a process or system by its results or effects, e.g., in a biochemical pathway or behavioral response.
Therein lies the problem. Most folks confuse reactionary forces as feedback. It’s not.
Real feedback examples: Engine governors (e.g. steam engines going “balls out”); Op-amps — feeding the output of an amplifier back into the grid.
Back EMF, for example (the phenomena wherein a DC motor acts as a reactive generator as rotational speed increases) is a reactive force and not “feedback”

Here is Willis with his same old wrong reasoning. Willis how do you explain all the abrupt past climatic changes based on your reasoning? How do you reconcile it?
The reason why you do not respond is because you have no answers.
In addition the data shows clearly that many volcanic eruptions have major climatic effects although they are short lived.
Willis conclusion.
Conclusions: The main conclusion that I draw from this is that the central paradigm of modern climate science is wrong—temperature does not slavishly follow the forcings.

LT

Makes sense, I think the fact that Earth exists in this magical state where water is balanced in a strange state where it can exist in 4 molecular configurations, solid, liquid, gas and clouds, creates a very complicated feedback system that is not easily understood. All of the various transfers of energies associated with convection, conduction, evaporation, condensation and precipitation are all made possible because 70% of the surface is covered in liquid water.

The study I have sent below has it spot on and is what most people subscribe to when it comes to volcanic effects versus the climate. It says everything I could possibly say about this subject. Just an excellent study and evaluation of how volcanos interact with the climate.
Look at table 3 of this report. I think they have it about right.
http://climate.envsci.rutgers.edu/pdf/ROG2000.pdf

If I understand the ramifications of Mr. Eschenbach’s “equilibrium response” of climate correctly – then the (few) documented historical instances of large volcanic eruptions causing crop failures is more likely a case of a systemic climate outlier reinforced by the eruption – as opposed to the eruption itself being the primary driver. Kind of like nitrous in a combustion engine vs. the engine’s fuel: the eruption (nitrous) makes the fuel derived engine power greater, but doesn’t offset the fuel type (wood vs. natural gas vs. gasoline).
I had wondered about this because my own personal examination of Pinatubo showed that the actual world climate response seemed so much lower than “expected” – which seemed discordant vs. many documented examples of poor weather due to Tambora.
But then I saw where an article where a historian went back and correlated written documentation of weather related events – primarily agriculture related – and showed a correlation with Tambora, but also with another unknown “super” eruption in 1807 (5 years before Tambora).
Now, the possibility of a completely unknown super eruption on a similar scale to Tambora within just 5 years – with no historical record other than crop failures – is certainly possible. But then again, a simpler explanation might just be that the 1807 to 1814 era was just a particularly cold and bad decade, kind of like the 1970s.

Dawtgtomis

Don’t forget that Tambora took place at the time the Dalton minimum was well underway, after most of the cooling had occurred. Same with the 1811-1812 extreme tectonic event of the new madrid fault. This correlation could suggest a relationship (or not) between those events and solar influences. Possibly the failed crops after Tambora were more the result of the solar influence and the subsequent climate changes of a solar grand minimum.
http://climexp.knmi.nl/data/it2m_land_best_1800:1820_13month_low-pass_loess1a.png

Dawtgtomis

Could it be that Pinatubo erupted during a time of lower cosmic radiation to the atmosphere (due to higher heliospheric density) and less of it’s aerosol emissions were energized to form clouds which cause cooling? Could the lower heliospheric density during the Dalton minimum be part of the difference?

gbaikie

I think it’s only the bigger eruption like Tambora which have much cooling effect.
So anything which has ejecta of over 20 cubic km of rock into stratosphere.
A cubic km of water is 1 billion tonnes, cubic km of rock is over 2 billion tons.
So if had say 5.1 billion tonne of rock put into higher atmosphere and earth has 510 million square
km, on average it’s 10 tons of powdered rock per square km. Or .01 kg per square meter.
Which should begin to effect the clarity of the open oceans. And while it’s in the atmosphere it also has an effect..

I hate the word forciing . Just give me differential equations .
Thanks for dissing this jargon papering over a lack of solid applied math education .

Dawtgtomis

Willis, if you’re still watching this thread, I am curious if this theory also would apply to nuclear explosions or impacts with asteroids, etc.?

Finally Willis is treating all volcanic activity as if each eruption was exactly the same. What could one say. I guess. I throw my hands up when I hear these blanket statements being addressed to the climatic system which is dynamic, chaotic, random ,non linear which means given forcing applied to it is going to give different results, no matter what the source of the forcing, volcanic eruptions included.
This one cause climate effect reasoning with the climate result line is really getting old. I will oppose this because it is plain old wrong.
Not accounting for the location of the eruption, the explosive index of the eruption, the amounts of SO2 from the eruption, how isolated or not the eruption was, the Initial State of the Climate at the time of the eruption for example the Ice Dynamic, all of which make the neat conclusions presented here to be nothing more then some norm with out regard to the specific dynamics of the volcanic eruption itself and the Initial State Of The Climate which are not going to give the same outcomes he wrongly keeps suggesting.
While I am at it your line of reasoning just does not reconcile with what the historical climatic record shows, as produced for Ice Cores. This thermoregulation theory you try to present is proven wrong time and time again by the historical climatic record.
It is time to think again.
http://wattsupwiththat.com/2013/06/02/multiple-intense-abrupt-late-pleisitocene-warming-and-cooling-implications-for-understanding-the-cause-of-global-climate-change/

Douglass and Knox published on this a little over ten years ago (http://onlinelibrary.wiley.com/doi/10.1029/2004GL022119/full). They used a linear systems feedback model and concluded. Their conclusion: “results are contrary to a paradigm that involves long response times and positive feedback”.

Willis Eschenbach

Thanks, Thomas. I had a distant memory of that but I haven’t read it. I’ll have to get a copy and get back to you. I do note that there were two comments, here and here, that claimed that D&K were wrong. These analyses are interesting in themselves. Santer et al. argue that D&K ignored the deep ocean … I’m not sure how much difference that would make. Robock argues that the Santer conclusions are correct, and that there is no negative feedback shown.
Without reading the paper, I’d have to agree with the D&K conclusion that there is what they call “negative feedback” … with reservations. The effect of the complex thermoregulatory system is to maintain the temperature in a fairly narrow range (e.g. ± 0.3°C over the 20th century). As such, whether the disturbance is too much forcing or too little forcing, the system acts in a proportional “Le Chatelier” manner to move the system back towards the status quo ante.
If you wish to analyze that as a simple feedback with a single feedback factor tau, you’ve only done half a job. Oh, you’ll get an answer, but it needs to be placed in the Le Chatelier context to make any sense.
The answer you get from a Le Chatelier analysis is the strength of the restoring force. Note that the strength of this restoring force has nothing to do with the current forcing of the system. Let me give you an example.
On a cool day, the cumulus cloud field in the tropics develops later in the day, letting in more sunshine. And if the next day is warmer, the clouds respond to the increased warmth and moisture by forming earlier and cutting out some of the sunshine. This simple system has kept the tropical temperatures relatively stable for billions of years.
Now, the variations in the ground-level tropical sunshine is what I’ve called the “restoring force” above. It acts to keep the temperature within some narrow range. Note that on a cool day this cloud system turns up the heat, and on a warm day it turns down the heat … but the incoming top-of-atmosphere (TOA) solar forcing is the same in both cases. So clearly, the temperature control system acts independently of the total incoming TOA forcing. The clouds form based on temperature, not basedn on the strength of the sun, not based on the volcanic aerosols, not based on the CO2 levels. The clouds form later when the temperature is cooler, and they form earlier when it is warmer, and they pay no attention to the forcing levels.
This shows that temperature is NOT a function of the TOA forcings such as solar or volcanic forcings, neither a simple feedback formula nor otherwise. Instead, a powerful active system, with tropical cumulus as only one component, acts constantly to keep the global surface temperatures from varying more than the above-mentioned ± 0.3°C per century.
And that is the ultimate reason why it is wrong to conceive of what is going on as being a simple feedback of the input forcings of the type used by Douglass and Knox in their analysis … because ultimately, global surface temperature is NOT a function of TOA forcing, and the “feedback” concept implicitly and incorrectly assumes that temperature IS a function of TOA forcing, just one with feedback.
Best regards,
w.

Mike M. (period)

Willis,
Interesting, but I do not find this convincing. My problem is that you do not seem to have investigated the question of whether the data are sufficient to see the effect you look for. The available solar energy data are clearly quite noisy. They are also likely to be affected by El Nino (I think there was one in 91-92) and La Nina events. So your failure to detect an appropriate signal due to the eruption could be, as you suppose, that the signal is not there or it could just be that the signal is lost in the noise. Without addressing the latter, your case for the former is unconvincing.

Willis Eschenbach

Thanks, Mike. That’s why I did the hemispheric analysis. If “the signal is lost in the noise” then we would not see a larger, quicker effect in the northern hemisphere observations than in the southern. But we do see that, in both the absorption and the albedo data, and exactly as theory suggests. This greatly increases the odds that it is a real signal.
w.

Mike M. (period)

Willis,
“This greatly increases the odds that it is a real signal.”
Maybe by a factor of two. Seems to me like there is a 50-50 chance of having the noise respond in one hemisphere ahead of the other.
It is oh so easy to see what you want when you have autocorrelated noise. I tend to be skeptical whether it is what I want to see, or not.

ulriclyons

More likely the eruptions cause El Nino.

FerdinandAkin

I can’t wait for Willis to start including data from NASA’s OCO-2 satellite in his analysis.

Dawtgtomis

Access to that data appears to be forbidden to all except the ‘science elite’.

Rob Morrow

Excellent post Willis! How does the response from El Chichon, or other major eruptions, look when analysed using the same method?

Rob Morrow

Pamela Gray

I am less titillated by smaller volcanic events (that I think the global weather pattern system recovers from within a season or two) than I am larger catastrophic events and their interactions with ENSO timing and memory mechanisms. It is now generally accepted that under normal conditions ENSO processes have memories related to the normal delayed oscillating La Nina to neutral processes that are somewhat randomly interrupted by El Nino events, especially if La Nina conditions hang around too long. The results of this overall process and its many different short and long term pattern variations are then echoed significantly throughout the globe through its many oceanic/atmospheric teleconnections. It is also generally accepted that they do NOT cancel out over long term time scales but instead of short, long, and very long patterns of variation. For further information the following webpage is a good place to gather educational understandings of ENSO processes http://faculty.washington.edu/kessler/.
Now add a catastrophic blow that pumps out copious amounts of sulfuric acid into the stratosphere along with near continuous pulses after the initial event. And place this catastrophic blow directly in the path of ENSO processes that depend on clear sky solar insolation to replenish copious amounts of energy lost during El Nino events. For me, that is where the money is in terms of discussing sudden and severe global cold periods that result in multiple years of flora and fauna death. And because ENSO processes are interacting with this disruptive catastrophic event, the resultant ENSO disruption echoes across the global weather pattern oceanic/atmospheric systems in a variety of ways and timing. These effects, once set in motion in terms of a less than normally recharged ocean, continue in spite of the eventual clearing of stratospheric veiling and may take decades to fully recover from.
Unfortunately, the last catastrophic event (1257) does not have the fine scale of sensor data to inform us as to the accuracy of its echoed effects on global climate processes. So at this point, it remains a conjecture, but one that is spurring a debate that is heating up http://www.pnas.org/content/111/28/10077.full.

Pam your line of reasoning is correct

Pamela Gray

Typo: “It is also generally accepted that they do NOT cancel out over long term time scales but instead [have] short, long, and very long patterns of variation.”

Sturgis Hooper

How does it feel to be in bed with Michael Mann of the Inappropriate Tree Rings?
The Warmunista phony paper you cite is is pure, unadulterated garbage.
In fact, the period 1250 to 1300 was one of the peaks of warmth during the MWP, as you’ve repeatedly been shown.
Volcanoes have no climatic effect, only on weather for much less than ten years. Even tropical VEI7 eruptions.

Sturgis Hooper

PS
The coldest 40 years of the LIA were during the Maunder Minimum, not the Dalton, even with the boost downward of Tambora.

Pamela Gray

Sturgis, you fail to understand the significant difference in calibration between Mann’s malpractice attempt at temperature reconstructions and the significant work done by the authors of the paper I linked to. You also fail to understand Earth’s teleconnected system and it’s lagged temperature response to catastrophic atmospheric disruptions. Under normal conditions, the world’s temperature producing systems do not turn on a dime when it comes to its cycles (the Arctic and Antarctic cycle being a good example) and tend towards having a fading memory with various responses on a regional basis of its regimes. Evidence is mounting that catastrophic atmospheric events can indeed cause a regime shift that stays around awhile.

Sturgis Hooper

Pamela,
I’m pretty sure I understand the climate system better than your presumed expertise, not that anyone knows much about it.
But, if I may take their names in vain, Willis, Dr. Brown, Bob Tisdale, Bill Illis, Tony and other regular commenters here can explain to you at least as well as I why a volcano in 1257 wasn’t responsible for the LIA, as you and Mann presume. In fact I’m closer to your position than any of those esteemed commenters, since I allow for WX effects for years, just not for climatic effects for centuries, as you so unjustifiably imagine.
But then you could be much smarter and better informed than all of us. It’s possible.
Tree rings are not thermometers, period. Unless you have an ax to grind, like Mann and yourself.

Sturgis Hooper

PS
It’s not just the tree ring circus, but the fact that in order to get rid of the Medieval Warm Period, Mann et al also sink to citing volcanoes to explain the LIA.
Nothing could be further from the truth. Both the LIA and MWP are natural fluctuations, just like those which preceded them in the Holocene and in all previous interglacials. And glacials for that matter, but deeper.

ulriclyons

“randomly interrupted by El Nino events”
Not random but an amplified negative feedback to weak solar wind conditions, and volcanic aerosol cooling.

LT

It is just as likely that the stratospheric conversion of SO2 to H2SO4 from El-Chichon and Pinatubo had a long term warming effect that we are still experiencing because the conversion process altered the water vapor content and or ozone levels within the Stratosphere in a cascaded manner which would alter the radiative properties in the stratosphere in a stepped function that is seen in the RSS and UAH datasets.

Willis Eschenbach

LT July 30, 2015 at 9:19 pm

It is just as likely that the stratospheric conversion of SO2 to H2SO4 from El-Chichon and Pinatubo had a long term warming effect that we are still experiencing …

Thanks, LT. If you gave us some data to support your hypothesis of long-term warming having a stratospheric origin we could discuss its likelihood … but as it stands, it’s just another of the thousands of hypotheses about climate without factual support.
As such, I fear we cannot tell whether it is “just as likely” as anything else we might hypothesize, or not.
w.

LT

LT July 30, 2015 at 9:19 pm says:
“…It is just as likely that the stratospheric conversion of SO2 to H2SO4 from El-Chichon and Pinatubo had a long term warming effect that we are still experiencing because the conversion process altered the water vapor content and or ozone levels within the Stratosphere in a cascaded manner which would alter the radiative properties in the stratosphere in a stepped function that is seen in the RSS and UAH datasets.”
Nonsense. It has nothing to do with conversion of SO2 to H2SO4. There is no such thing as a stepped function in the satellite data. What is there is a an ENSO wave train that you obviously cannot recognize in your poor quality graph. It precedes the super El Nino and comprises five El Nino peaks with La Nina valleys in between. Look at figure 15 in my book and follow up the explanation.

LT

Arno, there is most certainly a stepped function that occurred in the stratospheric temperature record in which the stratosphere cooled in a steeped function after the effects of El-Chichon and Pinatubo that altered the radiative properties of the stratosphere.
http://wattsupwiththat.com/2015/07/29/why-volcanoes-dont-matter-much/#comment-1996836

LT

Unless your book can explain why the stratosphere dropped from a minimum of 212.5K to 212K after El-Chichon and remained at or above that temperature until after the effects of Pinatubo in which it dropped to 211.5 K and has remained at roughly that temperature since 1995.

Interesting Willis. There are other areas where this hypothesis might be explored such as the supposed climate disruption caused by impact events. I’ve personally thought that so far the effect has been exaggerated on mostly an almost anecdotal basis…”everybody knows” the great dinosaur extinction was “caused” by the climate changes associated with an asteroid impact.

This student has studied the entire Article by Willis and all the comments that followed. I conclude that volcanoes do have a significant impact in the hemisphere in which they are located but only for around a year. Then the pattern and trend of temperatures continues where it left off. I have long felt that forcing is a misnomer.

Pamela Gray

But that would not make sense in an oceanic/teleconnected system that when disrupted in any one of the major connections, would tend to echo that disruption, and if a major disruption, would put the system out of balance for quite some time and like ripples in a pond, continue to echo the memory of that event. It is also possible that the disrupted system could lead to a rebound greater than its initial state.

Dr. Spencer’s Conclusions. Again correct. We have the data.
The eruption of Mt. Pinatubo in the Philippines on June 15, 1991 provided a natural test of the climate system to radiative forcing by producing substantial cooling of global average temperatures over a period of 1 to 2 years