Guest essay by Neil Catto
In view of the possible reasons for the 17-20 year global temperature plateau and further to Willis’ post a couple of weeks ago “Volcanoes Erupt Again”, I have been working on the same subject from a different angle.
I used volcano data from the Smithsonian Institute; http://www.volcano.si.edu/
As volcanic eruption particulates (aerosols) are said to affect global temperatures, it would suggest there must be a signature of this within the long term temperature record of the Central England Temperature (CET) http://www.metoffice.gov.uk/hadobs/hadcet/index.html
Volcanic activity is measured using a scale called the Volcanic Explosivity Index (VEI). This is a logarithmic scale between 0 and 8 although in modern times (~2000 years) there has been none over a 7.
Fig 1 significant volcanic activity (VEI 5-7) since 1 AD
Figure 1 shows significant volcanic eruptions occur regularly. However, as the scale is logarithmic (x10 after VEI 2) the impact of the major eruptions should be shown as VEI km^3, the volume of ejected particulates. A VEI of 0 is a non explosive eruption emitting <10,000m^3 or <0.0001 km^3 whereas a VEI of 7 emits 100 km^3.
Fig 2 significant volcanic activity (VEI km^3) since 1 AD
In figure 2 using km^3 shows the far larger impact of aerosol emissions from VEI 7 volcanic eruptions.
Fig 3 volcanic activity between 1659 and 2013 (CET timeline)
The scale of figure 3 was produced to show how large the Tambora eruption of 1812 was, but hides most of the lesser activity (VEI 0-5).
We must also remember for each year it is the total number of volcanic eruptions within that year shown as km^3.
Fig 4 volcanic activity, CET 1659-2013
In figure 4 the enormous explosivity of Tambora in 1812 is cut off, but the VEI 6 and VEI 5 can be observed. I highlighted Tarumae 1739 because in my research of the CET record it appeared a major influence on the temperature record falling from 9.2 Deg C to 6.84 Deg C between 1739 and 1740 and recovery to 9.3 in 1741.
Apart from Tarumae, my observations of figure 4 do not clearly indicate the relationship between volcanic eruptions and changes in temperature. As such I isolated the six major eruptions of VEI 6 or 7 (10-100 km^3) during the 1659-2013 period.
In the following six figures I have analysed the temperatures, a year prior to the eruption, the eruption year, and the years after the eruption until the temperature recovery date (=/> the previous year temperature).
I have also taken into consideration and highlighted the locations of the eruptions, either as Northern Hemisphere (NH) or Southern Hemisphere (SH).
Fig 5 Temperature recovery Long Island
Fig 6 Temperature recovery Tambora
Fig 7 Temperature recovery Krakatau
Fig 8 Temperature recovery Santa Maria
Fig 9 Temperature recovery Novarupta
Fig 10 Temperature recovery Pinatubo/Hudson
|
Volcano |
VEI |
Year |
Hemisphere |
Temperature Diff ° C Eruption-1yr |
Recovery Years (-1+x yrs) |
|
Long Island |
6 |
1660 |
SH |
+0.25 |
0 |
|
Tambora |
7 |
1812 |
SH |
-1.56 |
6 |
|
Krakatau |
6 |
1883 |
SH |
-0.43 |
1 |
|
Santa Maria |
6 |
1902 |
NH |
-0.28 |
1 |
|
Novarupta |
6 |
1912 |
NH |
-0.69 |
9 |
|
Pinatubo |
6 |
1991 |
NH |
-1.11 |
8 |
Table 1 summary of major volcanic eruptions temperature recovery:
Long Island (SH) shows no effect on a global scale.
Tambora (SH) could be said to have impacted global temperatures by a decrease of -1.56 Deg C, however within the recover period there was also a decrease between 1995/96 of -1.32 Deg C with no major volcanic activity above VEI 3.
Krakatau (SH) appears to have little effect on global temperatures, showing minor decrease of -0.43 Deg C and a recovery in a year. The temperature between 1884/85 fell by -1.26 Deg C with no greater than VEI 3.
Santa Maria (NH) again shows little impact on a global scale, even within the same hemisphere, with a drop of only -0.28 Deg C and a year to recover. The temperature dropped between 1903/04 by -0.32 Deg C with only one eruption of VEI 4.
Novarupta shows a fall of -0.69 Deg C, however within the recovery time there were falls of -0.67 Deg C between 1916/17 with one VEI5 (1916) and one VEI 4 (1917) and -1.03 Deg C between 1918/19 with only one VEI 4 (1918) and two VEI 4 (1919).
Pinatubo shows a fall of -1.11 Deg C, within the recovery time the temperature fell -1.32 Deg C between 1995/96 with no more than VEI 3 eruptions.
Discussion:
The effect of aerosol emissions on global temperatures from volcanic eruptions appears very small and may not be discernable from natural variation.
Steven Mosher says:
March 11, 2014 at 9:18 am
Egads, Mosh, you are easily discouraged. When a scientist says something is possible, I usually believe them. But when a scientist says something is not possible … well, I reserve judgement.
In any case, your claim seems to be that the volcano effect is so tiny that it is lost in the noise. Which is certainly true, and that is the main point of this post as well as many of my own posts … but we have methods to deal with that.
An obvious method is to “stack” the records of the various volcanoes to average out the noise. I’ve done that exercise, as did Greg Goodman above. We came to the same conclusion—the effect of eruptions on global temperature is measurable but very small …
Another method is that we have long-term records of volcanic sulfates in the ice cores. This allows us to investigate longer-term interactions of volcanoes and temperature. I discuss this type of volcano/temperature analysis in Dronning Maud Meets the Little Ice Age.
So while the signal is indeed small as you point out, do not lose all hope … ve haff vays …
w.
Sorry, confusion of figure assignments. It is not your Figure 1 but Willis’ Figure 2 in your reference that the description in my comment refers to. Comes from jumping around too much. Along this line, your Figure 4 also shows absence of tropospheric cooling in CET beyond random variations, even for huge eruptions like Tambora. I had been wondering about that one and now I see that it fits in with rest.
Paul Homewood says onMarch 11, 2014 at 10:04 am:
“Hansen did an exercise on Pinatubo, which suggested maybe a global cooling of up to 0.3C for the first two years, then gradually tailing off over the next two or three.”
Paul – Hansen is ignorant of many things, one of which is volcanic cooling. That is not the worst mistake he made. His worst is the claim to the Senate in 1988 that he had discovered greenhouse warming. He discovered no such thing. What he did is to show a rising temperature graph that started in 1880 and peaked in May 1988. That was the highest temperature peak in 100 years, he said. According to him, there was only a one percent chance that this could happen by chance alone. Hence, it followed from this that greenhouse warming had arrived. But if you check existing temperature records you find no hundred year peak there because May 1988 is part of an El Nino peak. There are five El Nino peaks in a row in the eighties and nineties and his is the middle one of the five. You don’t have to be a rocket scientist to understand that calling an El Nino peak the culmination of a hundred years of warming makes no sense if there is a new El Nino formed every five years.
To Neil: The problem is that the VEI is not enough to describe volcanic activity. There are two more important features (1) was is a stratospheric eruption yes/no and (2) the crater diameters. Please take them into account. There are Holocene craters of 20 km diameter, which do show a significant temp drop. If you fiddle with the small stuff only, you get the small stuff temp drop only…But your conclusions are wrong concerning the big stuff, which you left out on purpose….Cheers. JS
climatereason says:
March 11, 2014 at 8:52 am
Tony, thanks much for this reply. It will shed light not just on your contributions but on those of several others who also favor the CET record.
“Submarine eruptions are a type of volcanic eruption that occurs underwater. An estimated 75% of the total volcanic eruptive volume is generated by submarine eruptions near mid ocean ridges alone, however because of the problems associated with detecting deep sea volcanics, they remained virtually unknown until advances in the 1990s made it possible to observe them.”
From Wikipedia
a b Chadwick, Bill (10 January 2006). “Recent Submarine Volcanic Eruptions”
The term “observe” is used lightly here as the supposed obsevations are accoustical in nature and rely upon related earthquake activity which may or may not accompany these eruptions. These would seem to be a very large part of the volcanic ball game which is not included in any of the statistical over massage of volcanic data I have seen on either side of the climate wars.
Joachim says:
March 11, 2014 at 11:56 am
Oh, don’t be a tease. Either give us the exact dates of the volcanoes you are talking about and the temperature dataset that shows a “significant temperature drop” from their eruptions, or go home.
“Cheers”? You accuse Neal of scientific malfeasance without a scrap of evidence to back up your nasty accusations, and you close with “Cheers”?
On second though … just go home …. Cheers,
w.
Arno Arrak says:
March 11, 2014 at 10:45 am
Sure ‘nuf … here’s my analysis of Hansen’s claims …
w.
The Economist magazine has (finally) acknowledged a ‘pause’ in global warming.
http://www.economist.com/news/science-and-technology/21598610-slowdown-rising-temperatures-over-past-15-years-goes-being
It ascribes the pause to aerosols, the solar cycle, and by ocean winds and currents.
“Gavin Schmidt and two colleagues at NASA’s Goddard Institute quantify the effects of these trends in Nature Geoscience. They argue that climate models underplay the delayed and subdued solar cycle. They think the models do not fully account for the effects of pollution (specifically, nitrate pollution and indirect effects like interactions between aerosols and clouds). And they claim that the impact of volcanic activity since 2000 has been greater than previously thought.”
Steven Mosher says:
March 11, 2014 at 9:18 am
You wrote in part and briefly: “. . . unless you have a large sample the noise on either side of the eruption [this] will make a good estimate hard to come by.” ( [this] inserted )
I believe the rest of your comment is consistent with that. If not, please, correct me.
This means, as far as I can tell, the signature of volcanic eruptions is too small to be easily distinguished from the surrounding noise. Or, putting it another way, the volcanic signature is necessarily minor. This, of course, is the thrust of the post.
Am I wrong?
Would it not be possible to overlay multiple events properly scaled to extract the volcanic signal more accurately?
Thanks for continuing to comment and taking the time to actually say something.
I am as always a confirmed skeptic on CAGW from the time of the previous horrible coming ice age.
I was studying graduate units regarding Thera and Pompeii. Thera erupted around 1600 BC – 1300 BC (there’s disagreements between archaeologists) and did change the climate for a number of years. So did Vesuvius in 1600 BC. Mount Ararat too. One Chinese chronicle reports seven years of drought, frost in summer, and the sun was obliterated for years. So a huge Volcanic eruption like Thera can affect the climate for a number of years and cause great movements of people seeking a living from other peoples resources, like the sea people. I can not understand why people still live in Naples and near Mt Vesuvius, because when it eventually goes up, those not able to evacuate will be covered like the Pompeiians.
One might conclude from the two really heroic eruptions in figure 2 that the first ushered in the medieval warm period, and the second the modern warm period.
Maybe the particulates are just a short term effect (there may be meaning in the simple vs. multi phase recoveries). Maybe the real dude is the water, by far the largest volcanic ejecta, and just plain ol’ mass.
Don’t get me started on the correlation between Large Igneous Provinces and temperature…
The CET does not respond much to anything, just like most things from England.
“… indeed temperatures had dropped sharply several years before 1257 and recovered very quickly afterwards.”
Ed Caryl (http://notrickszone.com/2013/12/22/disappearing-excuses-aerosols-likely-not-behind-the-warming-pause/) : “… El Chichon and Mt. Pinatubo pre-1995 resulted in warming …”
Why “… very quickly afterwards.”, “… El Chichon and Mt. Pinatubo pre-1995 resulted in warming …”?
Climate response to volcanic eruptions is very diverse (I recommend the book: Climate and ecosystems, D. Schimel, 2013).
I. CLAW hypothesis.
Initially, volcanic dust fertilize the ocean = increase amount of aerosols = increase cloud cover. Volcanoes destroy stratospheric ozone, however. Ozone in the stratosphere long after the eruption remains at a low level (his amount increasing very slowly). Few stratospheric ozone – effect: an increase (even double) ULV in the troposphere. ULV destroys phytoplankton = cloud cover decreases …
Craig Idso (http://ourchangingclimate.wordpress.com/tag/craig-idso/) says it’s a very risky hypothesis, but …
Ozone depletion: ultraviolet radiation and phytoplankton biology in antarctic waters, Smith RC, Prézelin BB, Baker KS, Bidigare RR, Boucher NP, Coley T, Karentz D, MacIntyre S, Matlick HA, Menzies D, et al., 2009. (http://www.ciesin.org/docs/011-450/011-450.html) “A minimum 6 to 12 percent reduction in primary production associated with O3 depletion was estimated …”
(http://www.antarctica.gov.au/__data/assets/pdf_file/0016/22453/ml_390854214351852_00620phytoplankton_krill.pdf): “New research suggests that the growth of phytoplankton is reduced by 56% when stratospheric ozone drops below 17% …”
(http://media.tumblr.com/b3343931a391a8b77f6eb25aa926babd/tumblr_inline_muiwu6tBH71ro0ix8.jpg) – here we see, that the increase in phytoplankton most often precedes the decrease in temperature.
II. El Nino. Jochum et al, 2010. (Quantification of the Feedback between Phytoplankton and ENSO in the Community Climate System Model http://journals.ametsoc.org/doi/abs/10.1175/2010JCLI3254.1) shows that ENSO significantly influenced on phytoplankton, and phytoplankton also significantly affects on ENSO …
III. Stratospheric ozone also affects the content of water vapor in the stratosphere – cloud cover (…).
Conclusion: volcanic eruptions cools and maybe also warms the troposphere. The balance depends on many factors and, unfortunately, is not known.
Interesting. I’m not sure how valid the data from ancient history is, but, it confirms what many of us have found, already. For those who may be curious, I recently plotted all of last century’s VEI 5s and 6s against HadCrut3. There’s no distinguishable difference after the eruptions and the normal noise that we have. Sure, locally significant, but, very transient, but, on a global scale, one can’t see where it does anything. You can see the plot here, http://suyts.wordpress.com/2014/02/24/good-greif-time-for-another-volcano-post/ In it, there’s a link to some close up time scale snap shots I did earlier. IDK, I can’t see any definitive drop in temps pattern from the eruptions. Sure, there are some, but, there are also temp increases immediately following some. It’s just not there.
Neil
CET is the temperature of the Midlands region of England. It’s 11,000 sq. mi. That’s 0.006% of earth surface area. Not representative of global temperature. But assuming it is representative, your data show volcanic eruptions have big impact on global temperature. The average decrease in global temperature for one-year periods since 1950 is -0.09 C. Krakatau is over 4x larger and Pinatubo is over 11x larger based on your data.
Dr. Strangelove says:
March 12, 2014 at 6:57 pm
Actually, it is positively correlated with global temperature, and the correlation isn’t all that bad …
w.
Willis
If we can substitute CET for global temperature, that would be great! We don’t need thousands of weather stations around the world. No need to worry about UHI and improper siting of stations. And it shows volcanic eruptions have big cooling effect on the short term.
Dr. Strangelove says:
March 13, 2014 at 12:56 am
Well way back when, CET is about all you got so I guess for log history stuff you don’t have much of a choice. Bring in the time machine that will allow us to go back and place some more stations and this would all get a lot easier.
I suppose you could try and link Mount Etna, Italy—1669, one of the 10 largest volcanos in history (http://www.randomhistory.com/history-of-volcanoes.html) with a downturn in the CET
http://climatedatablog.wordpress.com/cet/
but unfortunately the temps were already on their way down so, unless they just knew what was about to happen, that seems unlikely.
The other ones that occurred in the more recent history do not seem to match either.
Richard
Just because you don’t have a time machine is no excuse to do lousy science. I would rather say I don’t know than pretend I know. Anyway in this case the result is as expected – cooling – but that could be just due to chance.
Dr. Strangelove says:
March 13, 2014 at 6:20 pm
http://climatedatablog.wordpress.com/cet/
is some cooling! It’s starting to look lie a set of bookends and with no volcanos that can be easily attributed to either end.
CET has always been considered to be a fairly good proxy for the rest of Europe given its position to the West, i.e. at the windward end. That is not a given but it has held quite well in the past.
Clearly, volcanic aerosols intercept and store up solar radiant heat and release it afterwards, increasing the net temperature. Eruptions are good for you!