Guest Post by Willis Eschenbach
I was out trolling for science the other day at the AGW Observer site. It’s a great place, they list lots and lots of science including the good, the bad, and the ugly, like for example all the references from the UN IPCC AR5. The beauty part is that the ones which are publicly available are marked “FULL TEXT”, so you can just search for that and step from study to study knowing that they’re not paywalled. So as I said, I was trolling through the full text links and I ran across an interesting study entitled Global Decadal Upper-Ocean Heat Content as Viewed in Nine Analyses by Carton and Santorelli, hereinafter C&S2008. Here’s their money graph, Figure 1:
Figure 1. Nine different estimates of the change on oceanic heat content, including one model and eight observational estimates. When comparing to other analyses, note that this analysis has oceanic heat content (OHC) expressed in units of 10^8 joules per square metre, and not the more usual global total OHC which typically is measured in units of 10^22 joules. The conversion is described in the last sentence of the caption. (Actually, I think that the caption to Figure 1 in their paper was from another context and wasn’t updated … but the meaning is clear).
I was hooked when I read the abstract, with its mention of the volcanic analysis, viz:
ABSTRACT
This paper examines nine analyses of global ocean 0-/700-m temperature and heat content during the 43-yr period of warming, 1960–2002. Among the analyses are two that are independent of any numerical model, six that rely on sequential data assimilation, including an ocean general circulation model, and one that uses four-dimensional variational data assimilation (4DVAR), including an ocean general circulation model and its adjoint. Most analyses show gradual warming of the global ocean with an ensemble trend of 0.77 x 10^8 J m-2 (10 yr)-1 (=0.24 W m-2) as the result of rapid warming in the early 1970s and again beginning around 1990. One proposed explanation for these variations is the effect of volcanic eruptions in 1963 and 1982. Examination of this hypothesis suggests that while there is an oceanic signal, it is insufficient to explain the observed heat content variations.
So what did I learn from this paper? To start with, I was totally unaware that there were nine different estimates of the changes in ocean heat content, so I learned that. And quite a bit more … including being reminded that this kind of “spaghetti graph” without error estimates is useless.
So the first thing that I did was to go get the error estimates on the Levitus data shown in Figure 1 (dashed purple line) and add it to the graph so I could see what was going on:
Figure 2. Same as Figure 1, but I have highlighted the Levitus data and added the vertical red lines showing the error of the Levitus data.
Now, I have long held that the error estimates in Levitus were underestimated … I would say that this graph agrees.
I also have to note in passing that I was unable to replicate their Figure 1 regarding the Levitus results. Using the data downloaded from the above link, here is what the Levitus analysis currently shows:
Figure 3. Figure 1 from C&S2008, overlaid with current Levitus results shown in red.
As you can see, there is good overall agreement with their data with the exception of the period from 1969 to 1984 … I have no explanation for this.
However, that’s not what I was interested in. I wanted to know about the volcanoes. For some time, I have argued in a variety of posts that the effects of volcanoes on the planet’s temperature were overestimated, and sometimes greatly so. So I was surprised to see their results for the eruption of El Chichón in Mexico. They took an interesting tack in their analysis. For each area of the ocean, they compared the average ocean heat content during the four years before the eruption, with the average heat content in the four years following the eruption. That seemed like a reasonable metric to me, and a good way to go about it. Figure 4 shows their results of the 9 analyses regarding the eruption of the El Chichón volcano in 1982:
Figure 4. Ocean heat content (OHC) net change from the four years before the eruption of El Chichón, Mexico, to the four years after the eruption. Upper 8 panels show the 8 observational datasets, and bottom panel shows the model. Note the different scales … presumably used because the changes in the model results are only about 2/3 the size of the observations. ORIGINAL CAPTION: FIG. 3. Change in 4-yr average heat content spanning the eruption of Mount Agung (1963). Prior to computing the heat content change a regression analysis is used to remove the effects of ENSO and a linear warming trend (see Fig. 2). … Changes exceeding ± 5 x 10^8 J m-2 are shaded. Lowest panels show the change in heat content from a five-member ensemble of the GFDL coupled simulation CM2.1 with complete aerosol forcing. Changes exceeding ± 3 x 10^8 J m-32 are shaded.
Now at first sight, all of that looks like confirmation that the volcano caused actual cooling and that my hypothesis of minimal volcanic cooling was wrong.
However, if the cooling is from the eruption, then why are there areas of warming? Why is the cooling localized in the region just below the equator in the Pacific, when the volcanic aerosols are initially from above the equator and then spread widely around the planet? And why is there not increased cooling in the region around the eruption site in Mexico?
The answer, as usual, lies in more observations. Figure 5 shows the corresponding 4-year averages for Pinatubo …
Figure 5. As in Figure 4, but for the eruption of Mt. Pinatubo in the Philippines.
As the paper itself says …
For Mount Pinatubo most analyses show general warming except in the western equatorial [South] Pacific.
General warming of the ocean after the largest volcanic eruption in modern times? Sure seems like that supports my claims … to me, the only conclusion that we can draw from these observations of the two volcanic eruptions is that we’re looking at normal variations in OHC, and that whatever the effects are, they are pretty dang small.
Close inspection reveals a final and very strong indication that the changes shown in Figures 4 and 5 are NOT from the two eruptions, but are natural variations of unknown origin.
The indication is that the shape of the cooling does not have the form that the modelers predicted. As the models show, if forcing ruled temperature the largest effect would be expected to be immediately downwind of the eruption site. Note in Figure 5 that of all of the nine results (8 from observations, 1 from the model), the only one showing North Pacific cooling downwind from Pinatubo was the model. You can see it in the model results, the blue area like an arrow pointing at the northern Philippines, with the tail streaming straight downwind in the north Pacific … but none of the observational datasets show that pattern of cooling downwind from Pinatubo.
Not only that, but look back at Figure 4. Care to guess which of the nine analyses claimed that there would be cooling downwind from the eruption in Mexico, in the area of the Caribbean and across the top of South America? Yeah … the model was the only one … and it didn’t happen. So even in the areas right downwind from the eruptions, we don’t find the expected heat content changes from the change in solar forcing.
The volcanoes pose a huge problem for the commonly held view that the changes in global average temperature are a linear function of the changes in forcing. The climate models are nothing but a mechanistic implementation of that circumscribed and simplistic hypothesis.
Now, we know for a fact that the solar forcing after Pinatubo underwent a large and fairly lengthy drop … but we don’t find either the amount or the pattern of cooling predicted by the models. Heck, not only that, but the predominate pattern after Pinatubo was warming, not cooling … once again, the only tenable conclusions are:
1) Whatever the volcanoes might be doing, they’re not doing what the model says or what conventional climate theory predicts, and
2) Whatever the volcanoes might be doing, they are not doing enough of it to even rise above the noise.
To me, this is simply more evidence that the underlying climate paradigm, the idea that changes in temperatures are a linear function of changes in forcing, is simply not correct. If it were correct, the eruptions would show it … but they simply don’t.
That’s why I describe myself as a climate heretic rather than a skeptic—I think that the most fundamental paradigm of how the climate works is wrong. The temperature changes are NOT a linear function of forcing changes as conventional climate theory holds.
As usual, my best wishes to you all,
w.
PS—Also as usual, please quote whatever you disagree with when you comment on it. That way we can all be clear just what you are referring to.
Effects of sun and eruptions: http://www.sciencedaily.com/releases/2014/03/140331114502.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily%2Ftop_news%2Ftop_science+%28ScienceDaily%3A+Top+Science+News%29
Volcanic eruptions produce lots of dust.
That dust is a fertilizer.
If you drop fertilizer in the ocean you will get blooms
I agree completely that current ‘models’ show no useful understanding of how the climate works. If CO2 caused warming and also warming caused CO2 to boil out of the oceans (as one can show), then millions of years ago, there would have been a catastrophic temperature rise problem. There wasn’t, as we know and thus this model is wrong. The real mechanism is some sort of complex interconnected labyrinth of causes, counter-causes, emergent phenomena and feedbacks. There is plenty of work yet to be done on this, more than enough than that which is required to re-employ unemployed CAGW scientists
Willis
Having looked at the historic record now back to 1000AD there is no doubt that the very large eruptions CAN have an impact on humanity, but the effect is generally much shorter than is claimed, and the scale of the impact is highly dependent on the volcanos location.
For example Dr Mann bemoans the fact that the 1257/8 super volcano does not show up in tree rings.
This eruption had a devastating impact in Britain, but the impact lasted around a season or two. The following year was a good one with no trace of the claimed effect lasting 5 or 6 years. Similarly we see this with Laki, whereby the church records show relief given to the poor because of the dire weather and thereafter things quickly reverted to ‘normal’ (whatever that means )
Things are further complicated that some studies seem to show that eruptions/emissions cause winter warming. They also do not show context, in as much for example the 1257/8 volcano impact was the culmination of a number of increasingly bad years that preceded it, so whether the volcano tipped things over briefly or the weather in that year was the culmination of some other natural process is difficult to determine.
Whatever the ins and outs, according to the volcano location, if the eruption is large enough it may have a short term impact, but as for the optical density of continual emissions from smaller volcanoes being a major cause of the slide into the LIA around 1250-1280 (as both Mann and Miller maintain) and this effect continued until around 1850…well this doesn’t show up in the historic record at all.
So, my take is that supervolcanos- according to location-CAN have a short term impact , but that their long lasting effect is exaggerated.
tonyb
I remember flying over the Pacific not long after the eruption of Pinatubo. We were flying from Taiwan to San Francisco in a 747 and the pilot came on the speaker and said that he was going to take the plane up to maximum altitude (41,000 feet at that time) in order to get above the ash cloud.
I was in a window seat and the cloud was clearly visible as a dispersed yellowish tinge to the atmosphere that we were barely above. We flew like that for hours.
What interests me, in light of your post is this. Whenever you look at the output of solar panels, anything that blocks the sun, be it high clouds, low clouds, dust, or whatever, the result is a decrease in the output of the panels, inferring a decrease in solar radiation reaching the surface. However, for clouds, which are very white, the result is a diffuse upward radiation, but not absorption from the clouds (you can easily see this in infrared satellite images where cloud tops equal the temperature at their altitude).
For volcanic gasses, diffuse dust, this is more than likely different with a lot of absorption. If there is a lot of absorption, there is a lot of emission, resulting in a temperature rise due to the increased thermal velocity of the dust particles in between absorption and emission time.
Willis this would give you your temperature rise. You should be able to see this in even modest volcanic eruptions in high resolution infrared satellite data. This could then be extrapolated as desired for larger eruptions.
Your milage may vary but it is easily testable from high resolution IR satellite data. There should be a clear difference in the temperature between the volcanic plumes and adjacent clouds.
There is good historical evidence that the immediate effect in downwind areas of the great Laki eruption in 1783 was an unusually hot and dry summer. Now Laki was exceptional since it was the only major fissure eruption to occur in historical times. Such eruptions are characterized by large “fountains” of lava along the fissures that discharge very large volumes both of lava, gases and particulates in a short time and close to the ground. These caused a widespread “volcanic fog” that apparently absorbed sunlight strongly and caused an unusual warming of the lower troposphere. In Iceland this haze was dense enough to stunt grass growth and cause widespread fluorine poisoning of livestock, which caused an extreme famine which is still remembered as “modhuhardhindin” (the haze famine). The haze was apparently still dense enough when it reached mainland Europe to cause significant mortality due to respiratory problems.
The subsequent cold winter of 1783-84 was presumably due to the relatively small proportion of SO2 that reached the stratosphere.
One can’t help wondering what the effects might have been from the really big fissure eruptions of the past, particularly the vast “Siberian Trap” eruptions at the end of the Permian which released at least a million times as much lava as Laki over a geologically very brief interval.
Willis: With respect to the Levitus data, I suspect Carton and Santorelli (2008) were using the older version (2005) of the Levitus (NODC) data, the version with the inconvenient 1970s to 1980s hump. And you’re using the recent version, which excludes the inconvenient hump.
With respect to the impacts of volcanic aerosols on OHC, the vast majority of sunlight is absorbed in the top 10 meters or so of the oceans, so it makes little sense that volcanic aerosols would have a noticeable impact on OHC for the top 700 meters. I suspect the volcanos show up in the models and reanalyses (like ORA-S4, used by Balmaseda and Trenberth) because they’ve had to tweak the ocean heat uptake in the models to get them to warm. But now the South Atlantic and Indian Oceans are the only oceans showing any warming…even to depths of 2000 meters.
Regards
volcanic gases when released into the atmosphere are just one more pertrubation into a robustly compensated (I.e. neg feedback) system. That system has a tremendous amount of thermal inertia stored in the oceans. No one minor event, like 92 Pinatubo, is going to cause a long term new equlibrium set point once the transient signal decays.
” The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible.”
I think the IPCC said that somewhere. Once upon a time.
I was out trolling for science
Trawling would be more appropriate 🙂
As soon as I became interested in climate science I looked at the models needed with their hundreds of inter-dependent variables and hundreds of possible tipping point mechanisms and chaotic behaviour on all scales and I said to myself, “I reckon I will look for a linear model…”
😉
Willis, Its not just the aerial volcanics, its also the major escalation in estimates of the number of submarine vents and all those parts of the mid atlantic ridge and the Pacific ring of fire that are under water. http://wattsupwiththat.com/2013/11/16/another-known-unknown-volcanic-outgassing-of-co2/ If there is a lot of CO2 being expelled it will be very hot CO2 you can be sure. I did ask Ian Plimer to check me out, but he is busy at the moment .
What I find really amazing about these climastrologists is the way they treat error bars.
For example, as BobT points out above it seems likely that the two graphs show different versions of the Levitus data, and hence the disagreement.
But isn’t it glaringly obvious to Levitus et al. that if they have two versions with non-overlapping error bars that they have almost certianly got it wrong? Narrowing an error bar with subsequent data and/or refinement is fine – but producing new non-overlapping results implies very strongly that both sets are wrong!
The ocean heat data is only for 0-700m depth so if there is some kind of deep water exchange or deep ocean overturning ? the Levitus data might still be in the ballpark but with little net warming of the oceans. I’m not sure how the PDO works, whether its an oscillation that involves oceanic stratification /deep current overturning or something else.
Volcanoes wouldn’t have much effect down to 700m, only near surface, its too short term.
“Prior to computing the heat content change a regression analysis is used to remove the effects of ENSO and a linear warming trend ”
So having removed a linear increase they find some cooling. An amazing result. Like all good climatology, they start with the ASSUMPTION that any long term rise is totally attributable to AGW and then look at what remains.
Here’s plot I just did inspired by Bob’s last thread. It looks at the W.Pacific bit
http://climategrog.wordpress.com/?attachment_id=912
It agrees with Willis’ observation that whatever volcanoes do seems hidden in the noise. A lot of what gets attributed to volcanism is spurious correlation with other non volcanic variability. This has been the main IPCC gig since mid 1990s. Spurious correlation to 2 or 3 bumps in late 20th c.
My volcano stack analysis also used the 4 years prior to eruption as the reference period. It shows tropics are almost totally immune to changes in radiative forcing and ex-tropics take a hit total energy regain previous SST after about 4 years ( in these accumulative plots a flat sections indicates SST is the same as the reference period).
http://climategrog.wordpress.com/?attachment_id=285
The implication would be some loss in OHC in extra-tropical regions after 4 years, non in tropics.
One important thing to note in OHC and SST is that the drops begin in 1980 well before the March 1982 eruption. More spurious correlation if that is attributed to El Chichon.
The way climate sensitivity is assessed by IPCC is by which models best reproduce the arbitrarily chose test period 1960-1990. They fiddle with params, do lots of runs of lots of models and rate the results by how well they reproduce the test period.
This could not be cruder and provided absolutely no checks for spurious correlation.
Anybody ever find a study dealing with UV radiation at the Earth’s surface in the years after these large eruptions.
We know that Ozone is depleted by meaningful amounts and the stratosphere temperatures exhibit a downward step change after the eruptions. This means that less solar radiation is then intercepted in this layer after an eruption than before.
In my mind, after the initial (far less than expected) downdip in temperatures after an eruption, there could actually be warming in the medium-term because more solar radiation is reaching the surface.
How about volcanic eruptions underwater. Is there enough heat to cause a change in the ocean temp? Also…..The lava that is produced….does it displace enough water to cause any rise in the ocean? I’m just curious.
Looking at the literature on volcanic forcing I found Lacis et al 1992, of which Hansen was co-author. They estimate the radiative effect of volcanic aerosols from direct physics ( scatter properties as function of droplet size etc. ) and from observations. They suggest 30 W/m^2 times the optical density. Then, in attempts to make GCM model output fit the data, instead of changing the model to make it work, the changes the INPUT DATA by lowering the correctly calculated value of 30 to 21.
The reason they need to do that is they will not use “parameters” aka fudge-factors, that result in negative feedback. Now if you won’t accept that climate compensates, you have to reduce the input. Which is what they did.
In fact there may be ground to go the other side of the Lacis et al value which IIRC was stated as +/-25%. Even with a value of 30 the net TOA reacts BEFORE the volcanic aerosol data rises.
If the volcanic forcing is set to AOD*40, then two do rise quite well together, however, this implies a very strong negative tropical feedback, and that is NOT open for discussion.
http://climategrog.wordpress.com/?attachment_id=913
I’m not sure how strong the case is for 40 , this initial months reaction may not be best be tackled by such a trival model but the current value is certainly a gross underestimation of the true forcing that has been rigged to make the models work (roughly) without the need for a strong negative feedback.
Bill Illis says: “In my mind, after the initial (far less than expected) downdip in temperatures after an eruption, there could actually be warming in the medium-term because more solar radiation is reaching the surface.”
I seem to recall making the very same point here in the last day or two, glad you found it convincing. 😉
http://climategrog.wordpress.com/?attachment_id=902
Now if volcanoes end up producing a durable warming effect, that’s really going to throw a amongst the pidgeons.
I seem to recall Bill Illis linking to the troposphere and stratosphere temperatures a few weeks ago. http://s22.postimg.org/d2tpesoo1/Daily_UAH_LT_LS_Volcs_Feb14.png
From Bill Illis march 11 2014 at 7:47am
In his recent post Bob Tisdale showed about two thirds of this troposphere temperature change in the SST. http://bobtisdale.files.wordpress.com/2014/04/figure-4.png
Obviously by including the top 700m of ocean (cf the top 10 metres) it is easy to make the signal disappear below the noise.
I have a question about underseas eruptions and geysers, do they not add heat to the ocean?
Just want to say thank you for this article, very interesting indeed!
K.R. Frank