Wondering Willis Eschenbach makes more mischief with volcanoes

Wondering Willis Eschenbach has a well-earned reputation for wandering off on a tangent and avoiding scientific research. He's done the same today at WUWT (archived here, latest here). He decided that two recent papers relating to volcanic forcing are "wrong". Not because he took any notice of the content of the papers - he didn't. Not because he took any notice of the observations reported. He didn't. He decided to reject the months of hard work by multiple scientists, on the basis of his own five minutes of "research".

Climate models and volcanic forcing

The two papers found evidence of volcanic forcing, coming from two different perspectives:

• Observed increase in Stratospheric Aerosol Optical Depth (SAOD) since 2005 (Ridley14)
• Multiple signals of volcanic forcing in sea surface temperature, atmospheric water vapour,  net clear-sky short-wave radiation, and elsewhere (Santer14)

One of the main points the scientists emphasised was that the CMIP5 models mostly assumed there was zero change in stratospheric volcanic forcing after 2000. They show that this assumption is not valid. Since 2005 in particular, there has been significant volcanic forcing, based on observations.

Significant increase in SAOD since 2005 (Ridley14)

This short section from the introduction of Ridley14 puts the findings and the implications for researchers in context:

It has often been assumed that only very explosive volcanic eruptions have pronounced effects on Stratospheric Aerosol Optical Depth (SAOD), and that since Mount Pinatubo in 1991, no eruptions have contributed noticeably to stratospheric aerosol content. However, observations since about 2005 revealed significant increases in SAOD [Stratospheric Aerosol Optical Depth] linked to a series of smaller eruptions [Vernier et al., 2011; Bourassa et al., 2012], with potentially important cooling effects on global climate [Solomon et al., 2011; Fyfe et al., 2013; Haywood et al., 2014].

Ridley14 found that, contrary to commonly held assumptions, it's been observed that there have been significant increases in SAOD since 2005. (The Stratospheric Aerosol Optical Depth (SAOD) indicates how transparent the stratosphere is. Aerosols can reflect sunlight, so they will limit the amount of solar energy getting to the surface.)

Volcanic signatures are apparent in multiple independently measured climate variables (Santer14)

Santer14 complements the Ridley paper in that it found multiple signals of volcanic forcing. What they did was remove the ENSO signal so they could look at various parts of the system. Signals of volcanic forcing were detectable in near-global averages of rainfall. The signals were "statistically discernible" in:

• spatial averages of tropical and near-global SST, 
• tropospheric temperature, 
• net clear-sky short-wave radiation, and 
• atmospheric water vapor. 

The press release explains what Ben Santer and his colleagues found:

The second Livermore-led study shows that the signals of these late 20th and early 21st eruptions can be positively identified in atmospheric temperature, moisture and the reflected solar radiation at the top of the atmosphere. A vital step in detecting these volcanic signals is the removal of the “climate noise” caused by El Niños and La Niñas.  

“The fact that these volcanic signatures are apparent in multiple independently measured climate variables really supports the idea that they are influencing climate in spite of their moderate size,” said Mark Zelinka, another Livermore author. “If we wish to accurately simulate recent climate change in models, we cannot neglect the ability of these smaller eruptions to reflect sunlight away from Earth.” 

WUWT protests and denier "claims" 

Ridley14 was published in late November. I've written about this already. The Santer paper was posted online on 29 December. The latest press release from the Lawrence Livermore National Laboratory. discusses the Ridley paper as well as the new paper by Ben Santer et al.

WUWT has had at least three protests about the observed recent volcanic forcing now. Two that were just a copy and paste of press releases under a "claim" headline. Plus now a protest from Willis Eschenbach, disputing the findings - except that he didn't. Instead he disputed something that the papers didn't claim.

So what was Willis disputing and what did the papers report?

Willis was disputing any increase in volcanoes. That's not what the papers reported. What the scientists reported was a measurable radiative forcing from volcanoes, and a "significant" increase in SAOD since 2005. These are not the same thing.

Perturbed solar radiation and global surface temperature

Willis likes to sound all sciency. This time he wrote:

Now, it is certainly possible that “small-magnitude volcanic eruptions substantially perturb incoming solar radiation”. There are lots of things that perturb incoming solar radiation, with clouds heading the list. Whether small volcano emissions in turn perturb the global surface temperature is a separate question.

The perturbation that Willis is talking about is the reflection of incoming solar radiation back to space by volcanic aerosols in the atmosphere. Willis is arguing that if there is less solar radiation reaching the surface, then it doesn't follow that there'll be a negative effect on global surface temperatures.  In essence Willis is proposing there is no link between incoming solar radiation and global surface temperature, which seems odd, particularly for a climate science denier. (One common meme of deniers is that "it's the sun" (not greenhouse gases).

The authors didn't count volcanoes

Willis then writes:

But for eruptions to be an explanation for the current plateau in global warming, the authors would have to show a significant increase in volcanic eruptions in the 21st century. And unfortunately (but predictably) I see no sign in either paper that they have even tried to do that.

He's wrong. The authors don't need to show an increase in volcanic eruptions. They only need to show an increase in forcing, which is what they showed. They showed an observed increase in stratospheric aerosol optical depth as well as volcanic forcing signals in multiple independently-measured climate variables.

There doesn't have to have been a significant increase in volcanic eruptions in the 21st century for whatever volcanoes were erupting to have had an impact on global surface temperature.  The impact depends on two main things - the composition and volume of volcanic aerosol ejected in a volcanic eruption, and where those aerosols are distributed in the atmosphere. The latter point depends a lot on where the volcano is located (material from equatorial volcanoes generally get dispersed more broadly around earth than do high latitude volcanoes).

As for what the scientists "even tried to do", well one of the papers, Ridley14, did list some of the potentially important eruptions. These included eruptions at the equator and at mid-to-high latitude - Ulawun, Shiveluch, Ruang, Reventador, Manam, Soufrière Hills, Tavurvur, Kasatochi, Sarychev, Eyjafjallajökull, and Nabro.

The Santer paper also looked at specific volcanic eruptions, contrary to what Willis claimed. For example, here are two extracts - of several (added a bit later by Sou):

Consider next the impact of the Tavurvur and Nabro eruptions. We obtain large negative values of r_i{S,X} during 60-month periods which sample the effects of these volcanic events (Figs. 2A, B). In tropical averages of the Vernier et al. SAOD data, the peak values for Tavurvur and Nabro are in November 2006 and September 2011, respectively. In the near-global SAOD averages, the corresponding peak values are slightly time-shifted, and occur in December 2006 and August 2011....

...During the period influenced by the eruptions of Soufrière Hills, Tavurvur, and Nabro, the peak values of V_RAW exceed 30% for near-global averages of SST (Fig. 4B). Clearly, the amplitude of these recent volcanic cooling signals is not negligible. The largest post-Pinatubo cooling signals are preferentially distributed in the final third of the "warming hiatus" period, and must therefore contribute to the hiatus.

Willis, in true fake sceptic fashion, decided to ignore the evidence provided. It would have demolished his story. Instead he went to the Smithsonian Institution's Global Volcanism Program to get data on volcanic eruptions. Which is fine. It was what he did with the data that was irrelevant, as far as these two research papers go. He didn't look at where the volcanoes erupted. He wouldn't have been able to tell how much impact any had on SAOD just by looking at the database. What he did was:

• count the total numbers of eruptions by year
• compute the average strength of all the volcanic eruptions combined
• count the small pre- and post-2000 eruptions (VEI<3)

By the way, in regard to the last dot point, the particular volcanoes listed in Ridley14 as potentially important, are mostly VEI4 not VEI <3. I checked.

Anyway, Willis noticed little change in any of these and declared:

Well, the papers may be correct in their claim that the effect of eruptions on the clarity of the atmosphere may have been underestimated.

But they are absolutely not correct in the claim that this underestimation reveals the cause of the recent 18+ year plateau in temperatures as being eruptions. There is almost no post-2000 change in either the number of eruptions, the strength of eruptions, or the number of small eruptions.

All Willis did was confirm what Ridley14 stated was the basis of the commonly held assumption: the incorrect assumption that there has been zero change in stratospheric volcanic forcing in recent years. What he didn't do was look at the data for SAOD itself. I'd say he didn't bother reading the paper (or the press release) properly, he was so intent on trying to make out that scientists don't know nuffin' and that he, a wondering Willis from WUWT, knew more than all the world's experts.

Willis' strawman

Now Willis reckons the papers claim something that neither paper claims. Nor is it mentioned in the press release. Willis wrote (my bold) "...the claim that this underestimation reveals the cause of the recent 18+ year plateau in temperatures as being eruptions." But they didn't make that claim. The Ridley paper made no claim that the entire cause of the "recent plateau" was volcanoes. Nor did it talk about any so-called 18+ year pause. What it did mention was that globally averaged surface temperatures have "increased more slowly" over the past 15 years (not 18+ years) than during the previous two decades. The main focus of the papers was on the CMIP climate models not providing for recent increases in volcanic forcing. Ridley14 listed suggested mechanisms that could have contributed to the observed slowdown in globally averaged surface temperature, including but not limited to:

• increased heat uptake by the oceans, 
• reduced solar output, and 
• recent volcanic eruptions.

The Santer paper also refers to the above, and adds [added a bit later by Sou]:

Uncertainties remain, however, and other modeling work suggests that key seasonal features of the "hiatus" are primarily attributable to changes in the Pacific Decadal Oscillation [Trenberth et al.]. Reliable quantitative partitioning of different external and internal contributions to the "hiatus" is still urgently required.

Willis completely ignores the data

Willis ignored the data and observations reported in the papers. He didn't attempt to explain the observed increase in SAOD as indicated in Figure 1 from Ridley14 (below).  Nor did he make specific mention of the volcanoes shown in the top chart (a), which are listed in the caption. Click to enlarge:

Fig. 1 (a) The SAOD time series for the period 1995 – 2013 for satellite data from Vernier et al. (blue), Sato et al. (orange), AERONET mean, averaged from 30-45°N, (white) with 25th to 75th percentile uncertainty (grey shading), Tsukuba lidar retrievals (36.1°N, 140.1°E) above the tropopause (thick black line) and 15 km (thin black line), and aerosol sonde measurements at Laramie (41°N) above the tropopause (red dots) and 15 km (red crosses). Potentially important equatorial (solid lines) and mid-to-high latitude (dashed lines) volcanic eruptions are shown for Ulawun (Ul), Shiveluch (Sh), Ruang (Ru), Reventador (Re), Manam (Ma), Soufrière Hills (So), Tavurvur (Ta), Kasatochi (Ka), Sarychev (Sa), Eyjafjallajökull (Ey), and Nabro (Na). (b) Ratio of integrated optical depth above the tropopause to that above 15 km from three different lidars and from the in situ observations. The inset contains the same data on a log scale to indicate the ratios greater than 5 that are cropped for clarity on Fig. 1 (a). Source: Ridley14

Ridley14 was based on observational data. That's right. It's not pie in the sky stuff (instead it's aerosols in the sky stuff). The paper states the sources:

Based on observations from lidar retrievals, balloon-borne aerosol sondes, ground-based AERONET sun photometers, and satellite data, we estimate increases in global total SAOD since 2000, together with associated uncertainties.

Willis based his surmises on a primitive count of volcanoes, without regard for where those volcanoes were located, and without explaining the increase in SAOD since 2005 as reported in Ridley14. And without explaining the signals detected in multiple independently measured climate variables, as reported in the Santer paper.

Deniers have no uncertainty!

Not surprisingly, Wondering Willis was much more emphatic in his claim that the scientists are wrong, and much more certain in his statements than the scientists are. Ridley14 states at one point:

Figure 3 suggests a larger volcanic contribution to recent global temperature changes than has been inferred from previous work. Clearly, it is desirable to obtain a more reliable quantification of the contribution of this and other forcings (such as changes in solar activity) to the hiatus [Schmidt et al., 2014], and to reduce uncertainties in observational estimates of the decadal rate of change of global mean temperature [Cowtan and Way, 2014].

Here's Figure 3, showing the estimated actual forcing compared to the zero change in stratospheric volcanic forcing input into "many climate models to date" after 2000:

Fig. 3 - (a) Estimated global mean radiative forcing is shown for datasets from Sato et al. (orange), Vernier et al. (blue) and AERONET mean (black) with 25th to 75th percentile range (grey). The dotted line indicates the baseline model used in many climate model studies to date, which includes no stratospheric aerosol changes after 2000.
 (b) The temperature anomaly, relative to the baseline model, including the AERONET mean (black), median (white), and 25th to 75th percentile range (grey), Vernier et al. (blue), and Sato et al. (orange) forcing computed for each dataset
(c) the total global temperature change predicted by the Bern 2.5cc EMIC in response to combined anthropogenic and natural forcing, including the reduced warming when considering the stratospheric aerosol forcing from the three datasets.
Source: Ridley14

The point is that most models had zero change in stratospheric aerosol forcing from volcanic activity. The Ridley team showed that there has been some significant forcing in recent years.

The climate model simulations evaluated in the IPCC fifth assessment report [Stocker et al., 2013] generally assumed zero stratospheric aerosol after about 2000, and hence neglect any cooling effect of recent volcanoes (see Figure 3 of Solomon et al., 2011). We find that satellite-based SAOD datasets generally agree well with SAOD inferred from lidar measurements above 15 km; however, they do not capture the full magnitude of the SAOD signal above the tropopause.

A bunch of deniers vs an interdisciplinary team of experts

Another point, as the press release stated:

The Livermore-led research involved a large interdisciplinary team of researchers with expertise in climate modeling, satellite data, stratospheric dynamics, volcanic effects on climate, model evaluation, statistics and computer science. 

Willis says:

Now, Willis’s Rule of Author Count says that the quality of any study is inversely proportional to the square of the number of listed authors.  

If Willis had a grasp of climate modeling, satellite data, stratospheric dynamics, volcanic effects on climate, model evaluation, statistics and computer science then his word might have meant something. Since the only accreditation the mob of WUWT deniers have is membership of the Scientific Illiterati Society, I propose to give their opinion the weight it deserves - which is zero. A stratospheric fail!

Based on my observations of WUWT, the more significant a scientific paper in denierland, the bigger the challenge to denialist memes, the more dumb protest articles there are on denier blogs. These papers aren't nearly as significant to deniers as Marcott13 or Recursive Fury or Cook13, for example.

From the WUWT comments

Curt asks a question:

January 9, 2015 at 7:12 pm
My understanding is that conventional wisdom says that “small” volcanic eruptions have less than proportional effect because their ejections don’t get that high in the atmosphere and are quickly rained out. Is this being challenged? 

The two papers don't challenge that. What they showed was that some of the material from moderate volcanoes does get up in the stratosphere, and the part that wasn't being picked up was in the stratosphere below 15km.

motogeek rather rudely says he prefers pseudo-science to science though not in so many words:

January 9, 2015 at 7:21 pm
*sigh* Most of the warmista’s won’t even admit there is a pause *at all* when you try to discuss the pause with them. I do see that articles like this have their place (getting them to admit there is a pause at all). How much can people have their heads shoved up their asses?

latecommer2014 is an ignorant climate conspiracy theorist. The type of person that forms the core target market of Anthony Watts:

January 9, 2015 at 9:19 pm
Why do we even consider these frauds. They are political scientist working at the bid of their controllers and contemptible 

bones is so relieved. He's found someone to tell him that all the scientific experts are wrong. More proof that Anthony Watts is attracting the people he wants.

January 9, 2015 at 7:39 pm
Willis, Excellent. Thanks for your effort. My gut feeling was that the studies were nonsense, but your finding and analyzing the relevant data took all of the guesswork right out of it. Thanks, much appreciated!

Jeff L  didn't read either paper, so doesn't know (or care) that Willis is wide of the mark. It's sufficient for him that a crank like Willis Eschenbach claims he is right and all the experts are wrong:

January 9, 2015 at 9:11 pm
Beautiful data Willis – I love it when alarmist arguments can be quickly dismissed with a little basic research & data. Exposes them for the political agenda driven bunch they are versus the science driven bunch skeptics are.
Well done!

Steven Mosher tried to set Willis straight, though he, too, misses the point that the authors weren't claiming that the slowdown was all down to volcanic aerosols - Ridley estimated volcanoes shaved 0.05 to 0.12 °C off the global surface temperature:

January 9, 2015 at 9:16 pm
“But for eruptions to be an explanation for the current plateau in global warming, the authors would have to show a significant increase in volcanic eruptions in the 21st century. ”
No. they would not have to show this.
Showing it would help, but its not necessary.
What’s important is total forcing. 

I see that later on, Willis Eschenbach doubles down on his denial and refusal to consider the evidence, and responds to Steven Mosher with:

January 9, 2015 at 11:22 pm (extract)
...No. they would not have to show this.
Showing it would help, but its not necessary.
What’s important is total forcing.
Say what? Given that as I have shown, there is no difference in the volcanic eruptions during the time of increasing temperatures and the time of the plateau in warming, then how on earth can the eruptions be the reason for the pause?
You’ll have to explain that claim a whole lot better than you’ve done so far, Mosh.
w. 

rishrac, I think, is trying for sarcasm. When it comes from a Dunning Kruger candidate it's not effective. They just look foolish.

January 9, 2015 at 9:53 pm
So does that mean the heat is still hiding in the oceans? Skeptics are not the intended audience for the “it’s the volcanoes” line. Why would they think someone wouldn’t look at the number and size? Oh.. I know, the truly faithful. It has to be co2!!! It’s a villain just lurking around the shadows, just waiting. That tipping point must be around here somewhere. 

I don't know what is going on in the head of TimTheToolMan - he doesn't understand the terms he's using is my guess. He's not making sense:

January 9, 2015 at 10:05 pm
Willis writes “Well, the papers may be correct in their claim that the effect of eruptions on the clarity of the atmosphere may have been underestimated.”
Only with the assumption of a very high sensitivity…and there’s not a lot of evidence for that.
Its another case of “making stuff up” to suit their message. 

There have been a lot more comments since I wrote this article. In particular there was a good comment from Frank who wrote that there has been an increase in VEI4 volcanoes:

January 10, 2015 at 12:33 am
Willis: The total number of eruptions is not important. Neither is the log mean annual VEI or the number of volcanoes with VEI <3. These are all straw men. The important factor is the number eruptions capable of transferring a significant amount of aerosol above the tropopause (where it will persist). The authors claim to have measured an increase in total aerosol since 2000 and claim it comes from volcanos weaker than the VEI 5 and 6 volcanoes that have traditionally been associated with cooling. That means you should have concentrated your analysis on volcanoes with VEI = 4. There were 14 volcanos with VEI = 4 between 2002 and 2011 and one with VEI = 5. Between 1900 and 1999, there were only 52 volcanoes with VEI = 4, 10 with VEI = 5 and three with VEI = 6. There clearly have been an unusually large number of VEI = 4 volcanoes during the hiatus than in earlier decades.

The key question is whether these previously ignored volcanoes resulted in higher levels of stratospheric aerosol than during earlier decades when VEI = 4 volcanoes were ignored. Most of the measurement techniques used during the hiatus were not available in earlier years. When the first paper was not behind a pay-wall, I thought that the methods that were used both before and during the hiatus gave contradictory results before the hiatus and therefore an ambiguous increase during the hiatus. The uncertainty in increase in aerosol forcing was about 50% of the total increase and this may have been a 25%-75% confidence interval.

A on-paywalled paper on this subject is available here: http://onlinelibrary.wiley.com/store/10.1029/2011GL047563/asset/grl28118.pdf

Wondering Willis was determined not to believe it.

There were also lots of people who believe the libel against scientists they've read on disinformation blogs, and were determined to spread it further. They fell for the Serengeti Strategy and, being fake sceptics, are satisfied with any lie as long as it supports what they want to believe.

You can see the latest archive here.

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Related HotWhopper articles

• Smaller volcanic eruptions helped slow warming, but deniers at WUWT don't believe it
• Wondering Willis Eschenbach has gone nuts about volcanoes at WUWT
• Wondering Willis, Volcanoes and the Dunning-Kruger Effect

References

Ridley, D. A., Susan Solomon, J. E. Barnes, V. D. Burlakov, T. Deshler, S. I. Dolgii, Andreas B. Herber, T. Nagai, R. R. Neely III, A. V. Nevzorov, C. Ritter, T. Sakai, B. D. Santer, M. Sato, A. Schmidt, O. Uchino and J. P. Vernier. "Total volcanic stratospheric aerosol optical depths and implications for global climate change." Geophysical Research Letters 41, no. 22 (2014): 7763-7769.  DOI: 10.1002/2014GL061541 (Subs req'd)

Santer, Benjamin D., Susan Solomon, Céline Bonfils, Mark D. Zelinka, Jeffrey F. Painter, Francisco Beltran, John C. Fyfe, Gardar Johannesson, Carl Mears, David A. Ridley, Jean-Paul Vernier and Frank J. Wentz. "Observed multi‐variable signals of late 20th and early 21st century volcanic activity." Geophysical Research Letters (2014). DOI: 10.1002/2014GL062366 (Subs req'd)