Get Laki, Get Unlaki

Guest Post by Willis Eschenbach

Well, we haven’t had a game of “Spot The Volcano” in a while, so I thought I’d take a look at what is likely the earliest volcanic eruption for which we have actual temperature records. This was the eruption of the Icelandic volcano Laki in June of 1783. It is claimed to have caused a very cold winter in 1783-1784. A study of the effects (see end notes) says:

… the 1783-1784 winter was extremely cold and snowy around the circum-North Atlantic. European temperatures were ~2°C below average for the late 1700s, and it was among the coldest winters in Central England …

Well dang … that sounds pretty scary. However, being a naturally suspicious fellow, I thought I’d take a look and see just what the temperatures actually said. I found eight records in the Berkeley Earth Surface Temperature dataset that went back that far, there may be others, but these cover a wide area of Europe. Here’s your puzzle:


spot the laki eruptionFigure 1. Eight long-term temperature records from Europe. All of them are aligned to start and end on the same date, but the dates have been removed

So … is the year of the “extremely cold and snowy winter” location number 1, 2, 3, or 4?

While you consider that question, let me point out that despite frequent claims of “unusual” or “extremely” or “unprecedented” and the like, I’ve shown in the past even very large volcanic eruptions cause little in the way of temperature changes (see end notes). The Laki volcano is in Iceland, so you’d think that the signal from it would be strong in Europe. And indeed, as the quote above shows, this is the common wisdom.

But as the temperature graphs show, the actual eruption makes little difference to the temperatures. The winter following the eruption of Laki is actually at location number 3, so there is some effect from it visible in all of the records. Looks like it is the one winter that was unusually cold in every one of the eight records.

But even then, it’s not that large and … and … oops … hang on a minute, sorry ’bout that. I got the numbers wrong. Here’s the actual situation regarding the winter of 1783-1784:


spot the laki eruption 2Figure 2. As in Figure 1, but including the dates.

As you can see, the winter following the Laki eruption is not the one marked with the red “3”. Actually it’s the one marked by the red “2” … and it is pretty unremarkable. In general it is NOT “~2°C below average for the late 1700s” as the quoted study says, that’s simply untrue. And in several of the datasets, it’s no colder than normal.

We do have one other dataset going back that far, the Central England temperature dataset. Here’s that data:


monthly cet lakiFigure 3. Central England Temperature (CET), late 1700’s.

Remembering that the study claimed that this was “among the coldest winters in Central England”, which winter looks like the big winner here?

In fact, far from being among the coldest all-time winters, the winter of 1783-1784 was not even in the top three for the quarter century 1775-1800 …


monthly cet laki plus datesFigure 4. CET including the dates.

My point is simple. We have been told a story all of our lives about how volcanic eruptions have large, widespread, and long-lasting effects on the global weather. It turns out that this was a scientific urban legend. In fact, the effects are small, localized, and short-lived.

UPDATE: For those who like averages, here are the averages of the eight station records.

average temperature anomaly 8 european locations laki

Regards to everyone,


AS ALWAYS: If you disagree with someone, please QUOTE THE EXACT WORDS YOU DISAGREE WITH, so we can all understand the substance and nature of your objections.

FURTHER READING: I’ve analyzed the effects of a number of large volcanic eruptions. In all cases, their effects have been small. See:

Overshoot and Undershoot

Prediction is hard, especially of the future.

Volcanic Disruptions

Dronning Maud Meets the Little Ice Age

Missing the Missing Summer

New Data, Old Claims About Volcanoes

BEST, Volcanoes and Climate Sensitivity

Volcanic Corroboration

Volcanoes: Active, Inactive, and Retroactive

Stacked Volcanoes Falsify Models

The Eruption Over the IPCC AR5

Volcanoes Erupt Again

Eruptions and Ocean Heat Content

DATA: Monthly mean HadCET data

Berkeley Earth Surface Temperature data

Laki Winter study quoted above


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Curious George

Just curious .. BEST does adjustments (maybe not that far back). Did you use raw data or adjusted data?


C’mon. Everyone knows (at least 97%) you use adjusted data for peer reviewed stuff. Only Koch backed shamans use raw data.

That was surprising. I would not have even thought to question that assertion.
So, now I’m wondering if climate modellers have any real grasp of the effect of aerosols on surface temperatures. Not that climate modellers necessarily understand anything else.

Willis Eschenbach

Karim, the models generally way overestimate the effect of the volcanoes.


Sort of makes sense, since the high volcano sensitivity will allow high CO2 sensitivity

Morley Sutter

Thank you Willis. You demonstrate that data is all important in science. Models, conclusions, opinions etc. without data simply are dross.


What is interesting is the range of from summer to winter during “the event”. It seems to get a couple of degrees warmer in the summer of 1783(?) but not significant. Winter has no significance what so ever.

Willis Eschenbach

intrepid_wanders November 18, 2014 at 8:16 pm

What is interesting is the range of from summer to winter during “the event”.

The problem with that is that the range from summer to winter is even larger in 1788-1789 and in 1794-1795. Which means that the swing during “the event” is not distinguishable from natural swings. Here’s the average anomaly of the eight stations:


Did I read that right? Did they use tree rings for their temp reconstructions?

If so, that could explain a lot. Tree rings resopond to many things other than temperature. CO2 in the air, and available sunlight I am sure would produce greater veriance in tree rings than temperature does.

Jeff Mitchell

Nah, they used volcano rings…

Richard G

Looking at the graph it looks like the following summer was the coldest in that record. Could it be the aerosols block some of the incoming IR?


Purely anecdotal: in 1992 the summer after pinatubo I was on a 650 mile canoe trip in the NWT of Canada and it was darn cold. We dragged across ice on most of the lakes and I doubt the ice fully went out on Dubawnt lake that year.

Richard G

I would think it would take some time for the aerosols to reach high altitude and disperse over a wider area. While in the CET graph presented here the summer of the eruption was the warmest and the summer after was the coolest, the average of the 8 locations shows that each of the summers after the eruption were cooler than the one preceding it.

Willis Eschenbach

Again, the problem is that those summers are not historically unusual in any way. So we can’t conclude much from them.

Richard G

Agreed Willis and thank you for adding the graph of location averages for it depicts the problem of attributing temperatures to volcanic eruptions.
In the averaged graph it shows the 3 following summers each cooler than the one before, but you would expect the opposite to happen. Each summer that passes you would expect the cooling effect from aerosols to decrease, not increase.

Jeff Alberts

And again, averaging those disparate stations into one gives you nothing physically meaningful.


Is BarryW right? Is this tree ring data?
If so, do modern era temperature reconstructions after local volcanic cooling events correlate well with actual temperature data?

Willis Eschenbach

JDN, Barry is referring to the study linked to at the end of the head post. They use tree ring data … me, I think that’s nonsense.

That’s why I mentioned it. They trusted proxy data and anecdotes but didn’t seem to verify their reconstruction against actual temps whereas you used actual temps. They got the answer they were looking for so a reality check didn’t seem to enter into their minds.

John F. Hultquist

I have no idea if this is relevant or not.
Volcanoes are not all the same. The characteristics of the eruptions differ as do the particles and gases. This site
. . . states that the eruption lasted eight months. Claims are made for an eastern USA temperature drop of 4.8 C degrees and a 1 C degree drop for the Northern Hemisphere. But I digress.
Did the sulfuric acid aerosol (80 X more than Mt. St. Helens – it says) emerge uniformly over the 8 months? How much of the gas from Mt. St. Helens came in one day with the early morning blast? How high into the atmosphere does material go for different eruptions? Mt. St. Helens is a subduction zone volcano. The Icelandic region is a spreading center.
All I’m saying is that the signatures of all volcanoes are likely not the same.

Willis Eschenbach

Thanks, John. Regardless of how uniformly the SO2 came out, my point remains. The variations in temperature from the Laki eruption were nothing like what has been claimed in the anecdotes and studies.

Willis Eschenbach

Folks, I put the further references down at the bottom of the post for a reason—to prevent having to answer questions like this one.
Eric, please read the post linked to above, Missing the Missing Summer.
Please do the reading before peppering me with questions. You get to read some interesting posts, and if you still have questions or disagreements, we can discuss them at that point.
Best regards,

Steve Keohane

Hi Willis, Thanks for looking into this. Latest Science News Nov 1, 2014 has an article siting two previously unknown documented observations indicating a large volcanic eruption by December 1808 from observation in Bogota Colombia of red, green and blue sunsets, and in Peru February of 1809 of prolonged twilight. I can’t find it on their online site. I know many have complained that Mt. Tambora eruption in 1815 was too late to cause cooling. This is interesting.

Have you cross ran the CET figures for the same time? The best data I could quickly find for max ranges during this period for CET for the decade around this event gives.
1781 … 20.9 … 01 June ……………… -2.9 … 23 Jan …………… -2.9 on 23 Jan 1781
1782 … 20.1 … 26 June ……………… -2.2 … 16 Feb ………….. -2.2 on 16 Feb 1782
1783 … 22.6 … 11 July ……………….. -7.1 … 31 Dec ………….. -4.7 on 26 Feb 1783
1784 … 20.3 … 07 July ……………….. -6.7 … 12 Feb, 11 Dec.. -7.1 on 31 Dec 1783
1785 … 19.5 … 27 June, 26 July ….. -6.6 … 20 Feb …………… -6.7 on 11 Dec 1784
1786 … 20.7 … 05 June ……………….-7.6 … 03 Jan ……………. -7.6 on 3 Jan 1786
1787 … 19.9 … 05 July ……………….. -2.2 … 28 Nov …………… -0.5 on 15 Nov 1786 & 27 Jan 1787**
1788 … 20.4 … 12 July ……………….. -5.9 … 30 Dec ………….. -2.5 on 8 March 1788
1789 … 19.2 … 05 Aug ……………….. -6.7 … 12 Jan …………… -6.7 on 12 Jan 1789
1790 … 21.8 … 22 June ……………… -0.6 … 29 Dec …………… +0.6 on 20 Jan 1790
The 1783 period does stand out and follow along impact to regional temps appears to be
Thoughts on Laki being more regional then your BEST Scatter version?

Willis Eschenbach

Jack, I don’t understand your question. Figures 3 and 4 are from the CET.

My apologies,
I was made a mistake. I scrolled past those charts, as I didn’t see any way to put them into context, example being average bars, as such I started thinking about the missing context instead of reading the actual context. My mistake.

Jerker Andersson

By just looking at the graphs it looks like the winter 1783-1784 could be about 2C colder than the average for the period of the graphs. It’s not the clodest winter, it is within the natural variation during that period but still I think the eruption helped pushing down the temperatures that winter so it bacame a bit colder than it would have been without the eruption.
In order for the winter to be exceptional due to a volcanic eruption it would require natural conditons that gives one of the coldest winters during the period. Then add some extra cooling from a volcano and it will be the coldest one. If those 2 things do not happen at the same time, the effect from an eruption is hard to notice by just looking on the temperature since the natural variations are larger than the effect from the eruption.


Benjamin Franklin had something to say about the weather/climate at the time of this eruption, as you are no doubt aware. He wasn’t one to make up stories.
Note that in several anecdotal reports, both excesses of heat and cold were reported at different times and places, so perhaps this might cancel out some of the regional averages. Also note, unusual cold was reported in the US, and perhaps they just assumed Europe was also affected. The graphs above only show European data.
It is an interesting eruption, in that both unusual heat and cold is reported, as well as widespread fog or haze. This follows up an earlier point that not all volcanic eruptions are the same, nor their effects.
I read somewhere that the closer they are to the equator, the more they effect both hemispheres, (sounds logical) and also they differ greatly in the amount of S02 produced. Pinatubo was apparently unusually high in S02 for its’ size.


You mean how anecdotal reports of last night — freezing temperatures in all fifty states, the coldest night on this date in over 100 years in NC, at least (it went down to 16F in my back yard — most of the last 30 years one would still be picking tomatoes from unfrosted vines in NC at this time of year but we had snow and/or killing frost back around Halloween) — might cancel out some of the reports that the average global temperature is supposedly 0.9C higher now than it was in 1903, the last time it got this cold this early in NC (and most of the rest of the US)? What’s one continent among friends? And not even forced by a volcano!
The problem is this, and Willis is quite right to point it out. It is pretty easy to:
a) See a volcano (or rather, know the date when some big volcano erupted), and;
b) Look at e.g HadCRUT4 and draw a line and attribute a dip right afterward as “cooling due to the volcano”.
It is not so easy to:
a) Look at e.g. HadCRUT4:
(to make it easy for you) and;
b) Guess where volcanoes happened.
In fact, it is basically impossible to do the latter, and if you include all volcanoes larger than some given size, it isn’t as easy to do the former as you might think — even largish volcanoes can have little effect. HadCRUT4 bobs up and down by as much as 0.6C over a matter of months! Indeed, it is if anything extremely surprising how much planetary spatially averaged temperatures oscillate around some sort of non-stationary temporal “mean”.
Bear in mind that nearly all of this record is seriously flawed in one important respect. Sea surface temperatures were absolutely terribly sampled and recorded for almost all of it. By “terribly” I mean using terrible methodology, using indifferent instrumentation, by people who didn’t care much about doing so, and sampling only along the “sea lanes” — and thereby excluding huge chunks of 70% of the Earth’s surface altogether.
To be specific, one thing that helped drive up this year’s supposedly impending “all time high” GISSTEMP is the transient blocking of the jet stream over a large chunk of the Pacific. SSTs skyrocketed over a part of the ocean that would have hardly been travelled in much of the 19th century. Remove the event, and global temperature estimates would be much lower. All such events are basically absent from all of the global anomalies, simply because there were huge chunks of the ocean for which no data was recorded, or for which what was recorded is not reliable.
It is amusing to look at the actual data for the PDO — the Pacific Decadal Oscillation that is probably a dominant factor in a prominent oscillation of global average temperature and a key component of the ENSO events that have easily as great or greater an impact on global temperatures than volcanoes. PDO data (which I happen to have in my possession) only goes back to 1900! Before that, no doubt the PDO happened, but we have no records from which it can be reliably extracted or observed. Half of the Pacific could have gotten as hot as it did last summer in (say) 1878-1880, when HadCRUT4 had an enormous and unexplained spike that very likely had little to do with CO_2. We have similar issues all over the globe — kriging data over sparsely sampled areas by its nature eliminates extremes in the interpolated areas. At best it presents a “relaxed” version of the interpolated temperature field, at worst it is just plain wrong, and either way the error estimates have to be much larger to accommodate either one.
It is interesting to contemplate how much of the assumed global warming anomaly is due to temperatures that we attribute to regions using models for which we simply lacked data in 1900, compared to data from the present that is computed using actual measurements for those areas.
The other thing that is interesting to contemplate is:
This is atmospheric transmission of direct solar radiation as measured at Mauna Loa, that is, above most of the troposphere and on “clear mornings”. Volcanic events are in fact easily visible in this record on top of Mauna Loa. I can direct you to numerous articles that “prove” that this directly observable clear signal drop in global insolation caused a temperature drop of 0.3 to 0.5C, e.g.
But if you plot:
then a) it looks nothing like this and b) you are right back up against Willis’ argument. This is just 20 years of HadCRUT4. Somewhere in there is Pinatubo. We know from having just looked at Mauna Loa that it caused a huge dip in insolation that lasted from 1991 through 1994 if not 1995, but to me it looks basically flat from maybe 1887 through 1996. To put it another way, a “dip” relative to what, exactly? The peak in 1991? The ten year mean? The twenty year mean? The linear trend:
? No matter how you slice it is unremarkable, and there are plenty of oscillations both up and down that are not related to volcanoes but which appear to be just as large. Well, it’s “remarkable” if you count the dip from the 1990 peak but really? Shall we then play the “let’s count the remarkable dips” game on the entire stretch, or on all of HadCRUT4?
Again, give the Mauna Loa observations or prior knowledge of when volcanoes happened, we can identify a possible dip after the fact, but we can’t do much better than a probability that any given dip in the record is associated with a volcano, and we absolutely cannot predict either the amplitude of the dip or its duration, partly because dips and rises of identical amplitude and duration are occurring without volcanic help at all, and such an “effect” takes place against the background of these natural oscillations and simply activate the same negative feedbacks and internal dynamics that give rise to the natural oscillations so that they are nearly indistinguishable.
This is in sharp contrast, BTW, to the effects of ENSO events. Interestingly, volcanos appear to produce highly transient cooling of the same order as natural fluctuations but don’t appear to “stick”. ENSO events appear to have some real staying power — they can actually shift the entire strange attractor, as it were, where volcanoes just cause a discrete jump on the same attractor. Or this might be one possible interpretation of what is, no doubt, a very, very complicated dynamic that is not well suited to this sort of projective linearized decomposition.
The one thing that we can instantly get from the Mauna Loa top of atmosphere insolation is this. It basically hasn’t changed from 1959 to the present. It is remarkably unremarkable. Yes, there are a few odd spikes and dips but it has stayed pretty much the same within around 1% except for volcanoes. This also emphasizes an extremely important point made a couple of posts below (as pointed out by Lindzen). The climate appears to be remarkably insensitive to direct variation of its atmospheric forcing. Let me repeat that. We can see variations in forcing by as much as 10% lasting years in the Mauna Loa data, but they produced almost no response at all in the climate — a response literally indistinguishable from natural variations of at most a couple of tenths of a degree, not sustained.
I’m sure that the fluctuation-dissipation theorem has a lot to say about this in a more quantitative way — if one simply inputs the 10% fluctuation in TOT insolation and does autocorrelation, I’m guessing it will tell us that a) the atmosphere cancels nearly all of the changing in forcing; and b) that it responds almost instantly and tracks the event decay tightly. So at the same time, the climate is never substantially disequilibrated with its inputs and yet its internal dynamics produces truly substantial variation all by itself.
Precisely as one might expect for a nonlinear chaotic complex open system in an open non-stationary equilibrium.


Thank you for a very interesting research on temperatures and the related phantom volcano signatures.
As you’ve mentioned before Earth has it own temperature modulation process for when temperatures spike. Perhaps there is a modulation process that handles transient drops in insolation. Substantial lengthy periods of lower insolation slowly cause lower temperatures, much like higher levels of insolation didn’t cause Dante’s Inferno on Earth the next day or even the next year.
Small changes in insolation = small changes in temperature over time? Enso as a modulator?
Dr. Brown:
Thank you for the additional research and emphasis on research requires analysis of observations.

Ulric Lyons

November 18, 2014 at 10:48 pm
“Also note, unusual cold was reported in the US,”
That is common for the US interior when there is a positive NAO in summer. Check, the US had a hot summer in 2012:

Willis– Dr. Richard Lindzen often uses climate’s quick recovery from large volcanic eruptions as an argument against the notion of climate being an overly sensitive system.
Here is a lecture by Dr. Lindzen explaining how volcanoes show climate seems to be much less sensitive than CAGW assumes.
(This is discussed at about the 31:00 minute mark of the following lecture):


A very lovely talk. His remarks on volcanoes are dead on the money. As I (also, independently) noted above, if the climate were highly sensitive, volcanoes would produce persistent and unmistakable changes in the climate that are simply not visible. Indeed, the order of the effects that are ex post facto visible (only) suggest a low climate sensitivity, not even an intermediate one, as a conclusion that can be drawn independent of assertions about natural or anthropogenic aerosols or water vapor feedbacks. It is again a case of the null hypothesis. One observes little difference in the kind or scale of response of temperature to volcanic events across all of HadCRUT4, which suggests that independent of any changes in aerosols due to humans and independent of any changes in water vapor feedback, the climate is basically not very sensitive to forcings and varies more on its own locally for reasons other than changes in forcing than it does in response to even very large changes in forcing.
And (woo-woo!) he actually cites me on one of his transparencies. That was a surprise!
I’m still working on a “paper” I plan to publish as a WUWT top post that goes into the GHG, total climate sensitivity, and carbon dioxide, although I keep encountering new ideas that it might be worth including and (since I decided to use R and do proper nonlinear least square fits) tweaking to fit the paper narrative. I’m curious, for example, whether inputting the Mauna Loa top of troposphere insolation as an additional modulator would alter the best fit or lead to anything like an improved fit.
NEXT up is going to be to put some actual numbers to the very observation he cites in the talk. What if we didn’t present spaghetti and/or multimodel ensemble means as if they had meaning? What if we directly compared each model in CMIP5, one at a time, to the actual climate? Where I’m perfectly happy to compare both the individual model runs (one run at a time) to the climate and the perturbed parameter ensemble mean for the individual model (one model at a time) to the climate, as I’m certain both will be instructive.
The goal will be to see if there is one single model in CMIP5 that can beat my two parameter, best fit of the actual physical model of CO2-driven warming to HadCRUT4 from 1850 to the present. I’m betting that the answer is not only no, but no in the profound don’t make me laugh out loud sense of no, they cannot, simply because not one strand of spaghetti in figure 9.8a of AR5 comes close to doing so, and those spaghetti strands are presumably PPE means per model, meaning that they will do even worse per run. But we’ll see. Sadly, that means I may have to use the world’s most annoying data retrieval system in order to get individual model runs (if I can figure out how to do so at all, as it was designed by somebody that wanted to make it as difficult as humanly possible instead of, say, simply creating a tree structure of the data in a straightforward common format and letting people browse the tree).
P.S. But Dr. Lindzen gets my name slightly wrong — I’m Rob, not Bob, to my friends and relatives and so on, and I would be honored indeed to be considered a friend…;-)

Bill Illis

Lindzen notes (which Wills is also noting here in a different way) that the climate impacts of volcanoes are way smaller than is expected and more likely indicates a very low climate sensitivity to “pertubation” as Lindzen likes to say but is more often called “forcing”.
The world climate should just cool off way more from the amount of sunlight reflected back to space by sulphate aerosols from volcanoes than actually occurs.
The surface impact that is.
Because as Greg notes below, we really do see a large volcanic signal in the stratosphere temperatures. We see a big spike in temperatures (just days after a major stratospheric eruption) and then a longer-term, long-lasting decline in the average temperatures in the stratosphere, a -0.5C step-change (most likely due to Ozone destruction).
So we have a minimal if not Zero impact on the surface, but a very large temporary increase, but also a large long-lasting decline in the stratosphere.
Maybe the CO2 forcing is similar. It has a large impact on some layers of the atmosphere, but a much lower impact on the surface.
We are also seeing larger impacts on water vapor levels in different layers of the atmosphere. The surface/very low level water vapor levels are going up fast but the higher layers are going down. That was not the prediction.
Is there a major re-write necessary in the theory based on these empirical results.
Climate science has basically 4 different layers of impact (the deep ocean, the surface, the tropopause, and the stratosphere). But they have gotten all of the impacts in these layers wrong. By a mile in some cases.
The stratosphere is losing water vapor but seems to be impacted more by volcanoes by a mile than by CO2. Volcanoes could explain 100% of the changes observed. The tropopause is not warming anywhere near projected, and the water vapor is declining, opposite to the big increase that was predicted, especially in the tropics. The surface is warming slower than expected but water vapor is close to predictions. The deep ocean is only absorbing about one-third of the joules that were predicted.
They need to start over. Maybe rgtbatduke or Willis could think about the above.

don penman

There seems to be a problem with acid rain from this eruption which would have made the drop in temperature seem more severe .


Willis wrote:
In general it is NOT “~2°C below average for the late 1700s” as the quoted study says, that’s simply untrue. And in several of the datasets, it’s no colder than normal.
Willis, while I agree with you that the effects were not that great and that natural variability can do that and more without volcanoes taking part on it, the claim that you quote seems true to me, not untrue. I didn’t check the specific data, I’m just eyeballing your plots of it, but looking at the average of those 8 stations, I do see that that winter was roughly 2C below the average for the late 1700s. And some others were 3 and 4 degrees lower as well. But still that was a cold winter, at aprox -13.5ºC for the minimum when about half of the rest of the years seem to be above -10ºC, and with three full months being lower than the minimum temperature of any month in about the 25% warmest years.

Willis Eschenbach

Sorry for the lack of clarity, Nylo. I was speaking of the individual records, not of the overall average (which I hadn’t calculated when I wrote the article).
So yes, it was a cold winter … but hardly unusually cold.

Please define “unusual”.
The winter most affected by Laki was the second most severe in the CET for the 18th century, except for one at the end of the Maunder and one early in the Dalton Minimum.
Here are all the winters rated “Severe” in the CET for that century (with ratings for the whole period):
1708/09 – 3.5c…SEVERE (tie, #4, Maunder)
1715/16 – 2.5c…SEVERE (#3, Maunder)
1739/40 – -1.2c…VERY SEVERE (#1)
1765/66 – 4.1c…SEVERE (tie, #6)
1779/80 – 4.3c…SEVERE (#8)
1783/84 – 3.5c…SEVERE (tie, #4)
1784/85 – 4.1c…SEVERE (tie, #6)
1794/95 – 1.4c…SEVERE (#2, Dalton)
For outside of solar minima:
1739/40 – -1.2c…VERY SEVERE (#1)
1765/66 – 4.1c…SEVERE (tie, #3)
1779/80 – 4.3c…SEVERE (#5)
1783/84 – 3.5c…SEVERE (#2)
1784/85 – 4.1c…SEVERE (tie, #3)
The winter of 1708/9 was the coldest of the past 500 years in Europe. It affected history by, among other ways, helping to destroy in the Ukraine the Swedish army of Charles XII, defeated at Poltava in 1709 by Peter the Great.
The exceptional winter of 1739/40 was caused by another blocking high, bringing in east winds and clear skies.

don penman

Thinking about it a little bit more we are being asked to pick out this event from a graph of data which may not be very accurate,only the people living through that event would really have known how severe the effects were.The world temperature graph is not a reality but it is constantly being presented to us as a such,you present these graphs in the same way..

Willis Eschenbach

Not true, Don. These are actual records from actual thermometers. So yes, the graph does in fact reflect the reality. As you point out, a world temperature average graph is just that, an average.
But these are actual observations.


Not true Willis, These are averages, not actual records. They appear to be a mixture of monthly, quarterly and annual averages. Averaging can hide all sorts of information.

Willis Eschenbach

At first you were opposed to the “world temperature graph” because it is “not a reality”.
Now you object because you observe (correctly) that I’m using monthly average of daily observations … but if you refuse to use monthly averages of meteorological data, at that point, you might as well just throw up your hands and quit, because generally that’s what we’ve got to work with. If we don’t use them we’re left with nothing … so if that’s your position, you might as well take up another line of interest rather than climate science, because generally that’s what we have.

Claude Harvey

Volcanoes eruptions are like tree rings. You got your temperature trees and you got your liar trees. You just picked one of those liar volcanoes, Willis.

B. Baak

Willis, Historical observations are also data. Why leaving those data out? With only temperature records you cannot get the whole picture. It will be interesting to see what the weather historian Jan Buisman will say in his upcoming book 7.

In the novel Lorna Doone, by Richard? Blackmoor, the great winter described therein, is said to be a description of the 1784 winter – if so, it was certainly a very severe winter in SW England.

Willis Eschenbach

Not sure what you mean. The hard winter in the book was set in the year 1683, and the author was born in 1825, so he didn’t see the 1783/4 winter … what is your reference for your claim?

Poor memory Willis – yes, 1684, sorry. I need another coffee.

Willis Eschenbach

Thanks, B. Yes, historical observations are also data. However, they are generally qualitative rather than quantitative, and they suffer from our all-too-human tendency to declare that something is the hottest in memory, or the coldest in memory, or the like.
For example, as quoted in the study I referenced above, Ben Franklin said:

…hence perhaps the winter of 1783-4 was more severe than any that had happened for many years …

Now, Franklin went to Paris in the winter of 1776, so he’d only been there seven years. So if he’s claiming that the winter is “more severe than any that had happened for many years”, he’s NOT talking from his own experience. He’s reporting someone else’s ideas about the history of Paris winters.
So what weight can we put on Ben’s repeating another unknown person’s historical observation? In my opinion, the record of one thermometer over that period is worth about ten of Ben Franklin’s retelling of someone else’s opinions …
Here’s another one from the same source …

George Washington complained of being stuck in Mount Vernon due to snow and ice conditions between Christmas Eve and early March …

Absent any other information about Mount Vernon, the roads, and how Washington travelled them, what can we conclude from Big George’s statement? Damn near nothing, I say.

Mike the Morlock

Hi Willis, sigh, I don’t dispute anything you say its just with Big George. He took a rage tag army across a river in the dead of winter on X-mas eve 1776. And then fought a battle with some of the best troops from Europe at Trenton. If he could not leave Mount Vernon it was ether he didn’t want to or it was not possible to do so, roads not with standing. Oh and for the record, the war ended in 1783. So maybe the snow was an excuse to take a well deserved rest.
And yes I thought volcanoes caused cooling. Now I have some reading to do.
Sigh, just had to burst my bubble.


Hi Willis, I always love playing spot the volcano.
Here’s one for you.
Some exlanation of how it affects surface temps is in the associated article:

My point is simple. We have been told a story all of our lives about how volcanic eruptions have large, widespread, and long-lasting effects on the global weather. It turns out that this was a scientific urban legend. In fact, the effects are small, localized, and short-lived.

Maybe you need a citation to back up the “long lasting” part. From what I’ve read the effects don’t seem to go beyond the initial distruption to atmospheric optical depth ( AOD). As can be seen above that is demonstrably wrong.
The “myth” if you like is that the effect of volcanoes ends when AOD settles and worse the sense of the long lasting effect the polar opposite of what is usually attributed to volcanoes and what most climatologists get by naive, simplistic regression analysis.
The late 20th c. warming was in large part due to volcanic induces changes in the stratosphere.


Once the true nature of the effects of volcanoes has been identified by clearly identifiable pattern in the stratosphere, the similarity to changes in the surface record can be seen:
Southern hemisphere SST:
GISS LOTI global land and sea average.

M Courtney

OK. So why did the idea that volcanoes lead to cold winters come about? I suggest it’s because winters feel colder after a large volcano.
We don’t just feel the temperature – humidity affects how we feel. A wet cold and a dry cold feel different. Do volcanoes (and their particulates) cause a change on precipitation that makes the cold feel unusual?
Just speculation but worth considering in my opinion.


Hi Willis
A couple of years ago I visited the archives of Exeter Cathedral looking for references to severe weather events. I found these for the 18th century;
1703 trees blown down in Cathedral Close by storm –December
1740 January ‘£23 to be given to poor in consideration of the severity of the season.’
1783 ‘Extra poor relief in extreme cold’ (due to Iceland volcano?)
1740 was a humdinger of a winter and brought to an end a decade of notable warmth which caused Phil Jones to investigate the 1730 decade in 2005 and admit that natural variability was much greater than he had hitherto realised.
As regards Laki, I have also said numerous times that the observational records do not illustrate any long term effects from large volcanos, even the super one of 1287 that Michael Mann got so excited about.
But undoubtedly the winter of 1783 was cold, although the effects do not seem to be long lasting.

Willis Eschenbach

Thanks, Tony. Yes, the winter of 1783 was cold … but according to the CET, it didn’t even make the top three in the quarter century 1775-1800. Hardly impressive.

You are mistaken about the CET record. Only one winter in the period you cite was more severe, and it occurred during the Dalton Minimum.
The second and third coldest CET winters during that quarter century were back to back after Laki:
1783/84 – 3.5c…SEVERE
1784/85 – 4.1c…SEVERE
Only 1794/5 was worse.
1794/95 – 1.4c…SEVERE


Wrong Willis ….. It is/was the coldest winter in the CET (1659 to present)…..
The DJF mean temp was -1.2C
The next coldest was 1740 at -0.4C


Also from the UKMO for stronger confirmation …..


Also the study you quote from does not say that the Laki eruption caused the 1683/84 winter … on the contrary (from abstract)…
“Data sources and model simulations support our hypothesis that a combined negative NAO‐ENSO warm phase was the dominant cause of the anomalous winter of 1783–1784, and that these events likely resulted from natural variability unconnected to Laki. “


Tony, the effects of the late 20th c. ones were not long lasting either. I do not know whether conditions would have been the same in pre-industrial period or not since it is possible part of what caused an increase in optical transparency of the stratosphere in my graphs above may has been removal of industrial aerosol pollution: “global dimming”.
In any case, it seems that changes in ozone are a significant part of the storey and that probably would have applied back then too.

4th coldest from 25 qualifies as amongst the coldest.
All that is proposed is that it was colder than it otherwise would have been due to the eruption which seems fair enough to me.

Willis Eschenbach

The claim was not that it was “among the coldest” in a quarter century. It’s that it was among the coldest in the entire record. It’s the fifteenth coldest winter in the CET record, which I would not call “among the coldest”. This is particularly true since it occurred in the earlier (colder) part of the record, where winters were generally colder.
Stephen, the claim is that the years following eruptions are unusual, that they are “years without a summer” that they are significantly colder than the rest. In that context, the fifteenth coldest winter is not unusual at all.


I had a similar question to that of EW about a “year without a summer” and followed your recommended further reading and ( to cut the waffle) that led me to your “thermostatic mechanisms”, the post of 2009 :
and the enormous no of responses that that generated .
Clearly the idea that , without human interference via CO2 ( if that is actual) there is a stable climate (dependent on continent geometry) to which the temperature relaxes, is a very powerful one .
However the date of that post and the references contained therein was 2009 . Have you revisited the thermostatic mechanism in similar detail more recently? . Because since 2009 the differences between GCMs and real world data have become even more obvious without provoking any change in attitude amongst the climate science community or their paymasters .
More intense publicly funded research on the thermostatic mechanisms might be sensible to establish the base on which any CO2 forcing is imposed as a second order effect.

It was the second coldest among the 25, not just among them, and it occurred during the warmer part of that quarter century, the latter part of which included the onset of the Dalton Minimum.
In the entire 18th century, only three winters were more severe and one tied it. All but one of those winters occurred during the Maunder or Dalton Minima. The exception was the famous winter of 1739/40.
I didn’t check the 17th or 19th centuries. The 17th of course included most of the Maunder, so contained a lot of severe winters. If you want to do a meaningful analysis, compare how 1783/4 did with winters during warm cycles of the LIA, not with its depths during solar minima.

Laki June 1783
Here are the record coldest months from CET back to 1659 around that period;
jan 1740 4th
feb 1740 4th
april 1770 6th
may 1740 2nd
Oct 1740 1st
nov 1740 8th
jan 1776 7th
jan 1776 7th
nov 1782 1st
april 1782 3rd
may 1782 12th
dec 1783 4th
mar 1784 12th
mar 1785 2nd
feb 1785 12th
march 1786 7th
nov 1786 10th
I think it is reasonable to say that SOME of the months following the Laki eruption of June 1783 were notably cold. However, it appears the cold had started the previous year in 1782 and in that context the following years were a continuation, perhaps tweaked by the volcano perhaps not, bearing in mind the other cold months/.years in the record, which is by no means exhaustive.
Any volcanos in 1740?

Richard Barraclough

Yes, indeed. There’s strong speculation, though no hard evidence, that the spectacular cold of 1740 was caused by the eruption of Mount Ichinsky, in the Kamchatka peninsula. This was by far the coldest year in the CET rercord (6.83 deg C), and was all the more remarkable in that it followed the benign decade of the 1730’s (decadal average 9.86 deg C). Winter 1740 was almost 6 degrees C colder than winter 1739.
For those who suspect the accuracy of 18th century thermometers, about 15% of the population of Ireland died as a result of the harsh weather. (OK, I know it’s not Central England, but it’s not far away, and I have the figures to hand!)
Getting back to 1784, the graphs presented in the article show monthly temperatures. Oon the scale used, this effectively hide the seasonal temperatures, which are the subject of the discussion. It’s not surprising that a few other years had a single month which was colder than 1784’s coldest month.
However, if we look at seasonal and annual temperatures, the winter (Dec, Jan, Feb) of 1783-84 was the coldest (1.16 C) since the aforementioned 1740, and the summer was also the coldest since 1740. Similarly, the annual temperature of 7.83 C was the coldest since 1740.
The only colder years in the whole CET record were 1692,94,95,98 (what was going on then?), 1740, 1814 and 1879.
It’s not surprising that 1784 was seen as an unusually cold year in England, and the spiky graph in Figure 4 hides this.

Richard Barraclough

Apologies for a couple of typos

I have looked at the data for the volcano you cite
Yes its last eruption was in 1740 but it doesn’t seem to be of much consequence. Phil Jones seemed uninterested in it in 2005 as a cause for the extreme 1740 winter, instead citing unexpected levels of natural variability

Robert W Turner

“The only colder years in the whole CET record were 1692,94,95,98”
Maunder Minimum, although the sun has nothing to do with these very minor temperature fluctuations we’re talking about. /s

Willis Eschenbach

Thanks, Richard. Here are the winters (DJF) of the CET:

Yes, the Laki winter was cold … but as the graph shows, it was far from unique or unusual.

December 1783 being 4th coldest in the entire CET record seems good enough to justify the original study. It is just that the other winter months brought it back up to 15th overall.
Willis is right though in suggesting that it is a short term effect from volcanoes with very variable regional effects.
Interestingly,the 2010 eruptions of Eyjafjallajökull in Iceland was followed by the coldest December in England since the national series began in 2010

The Ghost Of Big Jim Cooley

I first started getting interested in ‘global warming’ in 2003. I used to argue on the old BBC website then. My very first point was that the actual ‘proper’ thermometer wasn’t invented until 1714. Even then, we have no right to think that early measurements were very accurate. Old records simply aren’t good enough – about as good as taking the sea temperature from a bucket of water dragged by a ship!
We don’t know what to think. Even today, surface temps are taken by rotten location…and then adjusted! The temps in the atmosphere (UAH and RSS) are not actual temperature recordings. It’s all a joke. If any other ‘science’ used such practices, they would be akin to alchemy. The idea that we can measure differences of tenths of a degree between past times and now is amazingly laughable. We might use tree ring data from one tree, or a core of ice from one location…and infer that we ‘know’ what the temperature was. Climate ‘science’ is bringing all of science down. I predicted that back in 2003. As an atheist, I laugh at religion (with its books written by subjective believers, its 20th-hand accounts, and of course its total lack of any evidence at all). But science has been a love of mine since my college days in 1975. I am SO disappointed that this charade, this nonsense, this puerility of climate ‘science’ is allowed to get away with fooling the public that it is anything near accurate, and that it WILL damage ‘science’ itself. Climate ‘science’ is no better than religion – it really isn’t! And any scientist reading this should be shouting it at his/her colleagues.


I’d guess (without much evidence) that a tropical volcano, like Pinatubo, might have quite different climate impact from an (almost) arctic one like Laki. Any evidence for this?

Mike McMillan

Looks to me as though CET had a very warm summer then a cold winter, followed by a cool summer. The big drop from summer to winter would leave the impression that the winter was colder in absolute terms, while only very cold relatively. The subsequent cool summer only cemented the deal.

Pete in Cumbria UK

Having witnessed through the media and via conversations with peeps with a keen interest in weather, would the ‘cold summer’ just be a result of social interaction between people.
My example would be the recent floods in the South West of England. OK, maybe some places got a lot of rain but it was in a place and time that historically spent all winter underwater anyway. The landscape was man-made and then neglected through lack of maintenance, the switching off of drainage pumps and failed forecasts.
But it was what ensued after a Met Office muppet jumped up on TV. He solemnly declared, repeatedly, and then copied onto the main news headlines, that a tin-pot little village, somewhere no-one had ever heard about, cared about nor ever will very much (unless they actually lived there of course) had had TWICE AS MUCH RAIN as it normally got in a year.
Before you knew it, EVERYwhere in England had had twice as much rain. Everyone was talking about it and it was repeatedly reinforced by the lame stream media. Actual weather station data was simply ignored, nobody checked the reality. For a population permanently muddled headed, soporific and chronically depressed by a diet of starch and alcohol, exchanging tales of woe and hardship is second nature – reinforced ever more by the dirge of soap operas that are de-riguer viewing on early evening British TV. The pluvial downpour, well within the bounds of natural variability, that engulfed Lower Middle Nowheresville (Pop. 45) became the national standard.
Did something similar happen after Laki, a small isolated event (a low temperature reading somewhere) get magnified by confirmation bias and social interaction. Possibly the only situation involving real positive feedback in the whole climate system?
Would it be an idea (not really but ykwim) for Lunadonkey and his side kick John Crook to devote some of their energies to analysing this, instead of spending their days (and my money) slagging off skeptics as they do.


The Winter of 1783/84 was exceedingly cold in the American Southeast, both for its long continuance, extremely heavy snowstorms and freeze severity. Feb 1784 and Feb 1899 contain the
only two instances of ice flows passing out of the mouth of the Mississippi River at 29 degrees N
and being meet by ships in the open Gulf of Mexico at 28 degrees N.
Reference David Ludlum-“Early American Winters 1604-1820”.


Pete in Cumbria UK makes an astute observation about perception especially when it comes to weather.
In our area where harsh winters are the norm, the winter of 11/12 was soft and mild and everyone was noting how easy the winter was. I was speaking with a clerk and we were talking about the weather and I said ‘thank heavens the winter is more humane than last year’.
I’ll never forget her response. She looked at me with complete puzzlement and stated that global warming was making all the winters mild. She had completely forgotten the brutal winter we had just endured the previous year.

Reblogged this on gottadobetterthanthis and commented:

The only point, volcanoes are not nearly as important as we assume them to be.


The winter after the Laki eruption was colder than the previous 9 winters. Could it be that the other dips in the record indicate volcanic eruptions in other places that the europeans were unaware of?

Thanks Willis. This certainly again throws a wrench in our intuitive sense a volcano’s ash and sulfur must cause cooling.
I actually think it does cause cooling, but the cooling doesn’t manifest in the way our minds look for. Rather it manifests by shifting the jet stream. (I think it was Dr. Tim Ball who started my thinking down these lines, by suggesting a “zonal” jet stream would often become “meridianal” after a major eruption.)
What really messes with our minds is that volcanoes mess with the timing of ordinary shifts in the AMO and PDO which cause ordinary shifts in the jet stream from flat (“zonal”) to loopy (“meridianal.”)
Sometimes I mess with children’s minds to make them laugh, by pretending I don’t know how to push them on a swing. To push them correctly I would, of course, push them from the rear, and time my pushes correctly. Instead I pretend I don’t have a clue, and push from the side, or push at just the wrong time, which stops them dead rather than increasing their swings. The children delight in telling me what a fool I am, and lecturing me about when and where to push.
Some people seem to be inadvertently giving volcanoes similar lectures, by expecting the same result from every volcano, irregardless of the situation created by the AMO, PDO and jet stream as a starting point. Volcanoes don’t heed us, and push whenever they please wherever they please.
What I surmise Tamboro did in 1815 was to push just when the jet stream was in a loopy phase, thus creating a jet stream that was a super duper looper. Where 2007 pushed a lot of ice down through Fram Strait, after 1815 the entire, cotton-pocking icecap got discharged into the North Atlantic. If this occurred again it might please Alarmists, “Look how little ice is at the Pole! It must be warmer” until the North Atlantic being turned into ice-water gave Europe a modern “Year With No Summer.”
What I’m suggesting is that the effect of volcanoes is much more complex than merely the air being cooled.

The real effect of volcanoes on climate is if they inject a lot of debris, including SO2 into the stratosphere, but even that is not lasting long: a few months for the heavy particles and 2-3 years for SOx-water drops for the Pinatubo which was a one-in-a-century VEI 6 event. Most eruptions are a lot less explosive and don’t even reach the stratosphere. The VEI index is a logarithmic scale with a factor 10 of debris ejected for each point on the scale.
Eruptions of the Laki and currently the Bárðarbunga eject a lot of mass, but mostly low in the atmosphere, which has far less climate impact. Besides that, the emissions of SO2 and especially HF (hydrogen fluoride), where the latter is very toxic for sheep and cows, killed about halve of all animals on Iceland and a quarter of the population as result of hunger at the time of the Laki eruption. See the many references at Wiki:
They also mention a lot of haze over Iceland and Europe. If that is true, that may not show up in winter temperatures (heat retainment), and reflects sunlight in spring…
For those who haven’t been in Iceland: here a picture from the top of the main Laki volcano (40 km inland from the main circle road, extremely bad road, several rivers to cross!) towards the long fissure: over 100 smaller volcanoes were formed at that time:

So basically there may be an effect for a particular type of volcano in a specfic location that projects a great deal of the appropriate material high into the stratosphere, but basically these are very rare and have a short term effect, if at all?
So the LIA is unlikely to have been caused by the 1257 eruption and a couple a few decades later?

Hi Tony,
Some -long- time ago we have met…
Indeed, most of the heavy debris of the Pinatubo did drop out in a few months. Only SO2 remained in the stratosphere, was oxidized to SO3 by ozone and attracted water to slowly form drop large enough to reflect/deflect sunlight. As I remember well from some work, the deflection caused more photosynthesis, because more leaves which were part of the day in the shadow of other leaves received more of the scattered sunlight which caused more CO2 uptake. That is visible in the minimum CO2 increase in the year(s) after the eruption.
SO2 emissions in the lower troposphere in general drop out as dry deposit within a few days, with rain even faster, so their climate impact in general is minimal.
I had a few good references some years ago which did show the aerosol impact of explosive volcanoes, but as usual they are gone now…

Correct, as usual.
There is no significant difference between volcanism during the LIA and during the Medieval Warm Period preceding it or the Modern Warm Period following it. Indeed, so far the Modern WP has seen big eruptions at a higher pace than the average across the LIA.
OTOH, the LIA is associated with an unusual number and magnitude of solar minima.

Willis your data is wrong major volcanic eruptions have been shown time and time again to have major climatic impacts. They may be short lived but they are major.

Dr. Spencer agrees with most of us who think volcanic activity does indeed have a cooling effect. I would say over 99% of the scientific community has reached those conclusions.
Dr. Roy Spencer, Ph. D. says:
November 16, 2014 at 8:36 AM
It is a visible reflector, but also an IR absorber. The Earth Radiation Budget Satellite (ERBS) measured a 2%-4% increased reflection by the sulfate aerosols after the 1991 eruption of Pinatubo, but it also measured the decreased IR emission because the aerosol layer in the lower stratosphere was blocking the warmer IR emission from below. The solar reflection effect dominates, which is why volcanoes cool.
The increased IR absorption by the aerosol layer leads to a dramatic warming in the lower stratosphere after a major eruption.

Willis Eschenbach

Salvatore, I agree that “volanic activity does indeed have a cooling effect”, as you say … in fact I said in the head post that it does. The question is, how much does it cool, over what area, and for how long? As I said in the head post:

We have been told a story all of our lives about how volcanic eruptions have large, widespread, and long-lasting effects on the global weather. It turns out that this was a scientific urban legend. In fact, the effects are small, localized, and short-lived.

You’ve provided nothing to change my mind, and once again you’ve ignored my request to QUOTE THE WORDS YOU DISAGREE WITH. For example, you say “Willis, your data is wrong” … but you don’t say which data.
Sadly typical of your bluster,
In agreement with this and all the other thousands of studies which reach essentially similar conclusions.
One last post here, but this one is very enlightening and full of information on solar/volcanic relationships and how they due indeed effect the climate.

The effect of volcanoes has been well studied. Willis would benefit from reading the research. Many such studies have been linked on this blog in the past.
The effect of volcanic eruptions on weather depends on a number of factors besides their magnitude. An important one is where the volcano is located. Tropical eruptions affect global weather differently from higher latitude eruptions. Pinatubo displayed the effect of a large tropical eruption well.
On average, the effects on weather of an eruption big enough to matter is short term cooling followed by longer term warming, but neither persists for sufficient time to affect climate, although a prolonged period of increased volcanism might.

Irish chronicle shows cooling effect of volcanoes:

Effect on CCNs and creation of vog:
Naturally the USGS had to throw in “climate”, although single volcanic effects rarely last long enough to affect climate.


Thanks Willis, interesting as usual.
Could you clarify the scale of the last (updated) graph. It says ‘anomaly’, but that looks like a large anomaly differential to me (+12 to -12 ºc). But if they are actual temperatures -12ºc looks much too cold for an average European winter.
A quick explanation?
Thanks, R.

Willis Eschenbach

An “anomaly” is just the variation of the temperature around a certain arbitrary level. In this case the level is the mean of the data. I’ve subtracted the mean from each dataset so they could be compared.

Frank de Jong

After having a look at the data, like yourself, I found the data unconvincing of an effect.
However, when you look at the prevailing winds, Icelandic volcanic aerosols would be blown mostly southwesterly towards Newfoundland, and somewhat northeasterly towards Norway. Therefore, looking at Prague, Geneva and Milan doesn’t prove much at all either way. Looking at Trondheim seems to be the most relevant… and then maybe CET or Stockholm. But even there, the winter of 1783/1784 doesn’t seem “unprecedented”.
The historic reports of very cold winters might be related to the fact that 1783 seems to have had quite a warm summer. Maybe that had an influence on the amount of snow or humidity? As you will know, there’s a difference between absolute temperature and “perceived” temperature.


Its possible the CET is not a very good indicator of climate, at least what humans experience. Take for instance 1816 the year without a summer, caused by Tambora:
“Cool temperatures and heavy rains resulted in failed harvests in Britain and Ireland. Families in Wales travelled long distances as refugees, begging for food. Famine was prevalent in north and southwest Ireland, following the failure of wheat, oats, and potato harvests. In Germany, the crisis was severe; food prices rose sharply. With the cause of the problems unknown, people demonstrated in front of grain markets and bakeries, and later riots, arson, and looting took place in many European cities. It was the worst famine of 19th-century Europe.[9][15]”
Nothing impressive shows up during 1816 on the CET, even though history clearly documents it as a major disruption of climate and significant hardship for humanity globally.

The winter of 1815/16 was cold but not severe in the CET.
This is not surprising, since big tropical eruptions affect various parts of the globe differently. Tropical Asian Tambora’s effect on NW Europe was less than Laki’s, which went off in its own neighborhood. Tambora hammered NE North America worse than NW Europe because its effect on the Gulf Stream was less downstream than upstream, and Central England lies at higher latitude than New England, for instance.

Willis Eschenbach

I’ve come across a very interesting and very detailed account of the actual effects of the volcano. The main effect seems to have been an acidic fog. Inter alia they show this graph of the temperatures from 29 stations:

Note that the summer was slightly warmer, but the winter and the annual data was not unusual in any way.

You must have missed this part of the abstract:
“The summer of 1783 was characterized by extreme and unusual weather, including an unusually hot July in western Europe, most likely caused by perseverance of southerly air currents. The following winter was one of
the most severe winters on record in Europe and North America. In these regions, the annual mean surface cooling that followed the Laki eruption was about “1.3!C and lasted for 2–3 years. We propose that the upper troposphere/lower stratosphere aerosols from Laki disrupted the thermal balance of the Arctic regions for two summers and were the main mechanism for the associated climate perturbations.”
I’ve linked to another paper by Self above, on the effect of large eruptions.

In the same comment, a Hawaiian volcano observatory paper discusses vog.

you dont measure the effect by asking whether it was UNUSUAL in any way. wrong headed approach.
this isnt an abduction problem.
The problem is pretty simple.
X is the temperature that WOULD HAVE BEEN but for the volcano
Y is the temperature that was actually recorded.
The effect of volcanos is X-Y. simple.
But we dont have X. we will never have X. we could model X, but that’s not data its an estimate of what would have been.
Or If you do a simple regression you can see that the years with volcanos are, in general, colder than one would expect. the residuals can show that to you. Or you can stack the volcano epoche’s.. or detrend and stack
Which ever method you use ( physical modelling of X or statistically trying to separate out the additional cooling), one thing remains clear. We don’t have X. we will never have X and so any statements we make are going to be heavily caveated.

richard verney

Since you do not know X for any year when there was a volcano, one can never say “that the years with volcanos are, in general, colder than one would expect.”,

The Laki eruption lasted eight months during which time about 14 cubic km of basaltic lava and some tephra were erupted. Haze from the eruption was reported from Iceland to Syria. In Iceland, the haze lead to the loss of most of the island’s livestock (by eating fluorine contaminated grass), crop failure (by acid rain), and the death of one-quarter of the human residents (by famine). Ben Franklin noted the atmospheric effects of the eruption (Wood, 1992).
It is estimated that 80 Mt of sulfuric acid aerosol was released by the eruption (4 times more than El Chichon and 80 times more than Mount St. Helens).
The climatic effects of the Laki eruption are impressive. In the eastern United States, the winter average temperature was 4.8 degrees C below the 225 year average. The estimate for the temperature decrease of the entire Northern Hemisphere is about 1 degree C. The The top graph shows change in acidity in micro equivalents H+ per kg in the Greenland icecap. The bottom graph represents the winter temperature records in the eastern United States. From Sigurdsson (1982).

Besides devastating Iceland, Laki caused widespread famine in Egypt (1784), Tunisia (1784–85) and probably India (1783–84):
You probably won’t like the tree ring data or the modeling to explain the effects of the eruption on Egypt, but there are plenty of other data.
The Tunisian famine killed up to one-fifth of all Tunisians.
India had already suffered a famine in the prior year, probably resulting from El Nino-related drought, but the follow on might well have been worsened by the effects of Laki. Together the two famines killed about 11 million people there:


These posted above in a reply to Willis (in case overlooked)
Wrong Willis ….. It is/was the coldest winter in the CET (1659 to present)…..
The DJF mean temp was -1.2C
The next coldest was 1740 at -0.4C
Also from the UKMO for stronger confirmation …..
Also the study you quote from does not say that the Laki eruption caused the 1683/84 winter … on the contrary (from abstract)…
“Data sources and model simulations support our hypothesis that a combined negative NAO‐ENSO warm phase was the dominant cause of the anomalous winter of 1783–1784, and that these events likely resulted from natural variability unconnected to Laki. “


Late comer here, I have only scanned the comments above and may have overlooked the following topic. Back in the cold war days, the concept of a “nuclear winter” existed. Forecasts based on a program TTAPSS (sp?) predicted severe consequences resulting from nuclear explosions producing great quantities of atmospheric debris. The concept was “tested” when the Iraqi’s blew up the Kuwait oil fields. Memory serves me less well now days, but I seem to recall there was NO detectable effect on global temps. Does anyone have a better memory?

Your memory is basically correct:
The astronomical Dr. Sagan and his usual suspect cronies Dr. Ehrlich and Dr. Schneider were climastrologists then, as Dr. Ehrlich remains. Dr. Sagan died before being able to jump on the Watermelon climate bandwagon, but Dr. Schneider of course did before his demise.

The point is that to have a large but short (2-3 years) effect on climate, the emissions must reach the stratosphere, which was the case for the Pinatubo and a few other eruptions in the recent past and in part for the Laki, and are certain in the case of nuclear explosions, but not for the Kuwait oil fires. After a few days, the smoke/particulates of the fires rain out are dispose off on land or oceans…

Nuclear winter is as big a crock as man-made climate change, and based upon equally execrable models and false assumptions. Schneider at NCAR did at least have the integrity to lower the doomsday level in his later modeling after consideration of better soot data, to “Nuclear Autumn”.
Besides which nuclear war now would not produce the needed firestorms. First because “countervalue” targeting (bombing cities) by the superpowers is at best highly unlikely, as opposed to attacking military targets. Second because modern cities just don’t burn as easily as did Hamburg and Hiroshima, both of which cases required exceptional meteorological conditions. No firestorm occurred over Nagasaki.

In 1988 Russell Seitz of the Harvard University Center for International Affairs said that the models’ assumptions produced the results that researchers wanted to achieve and were an instance of “worst-case analysis run amok”.
Sound familiar?
Marxist academics happily abuse their positions of trust and will stop at nothing to further their ideological agendas.

Willis Eschenbach

Toneb November 19, 2014 at 12:34 pm

Wrong Willis ….. It is/was the coldest winter in the CET (1659 to present)…..
The DJF mean temp was -1.2C
The next coldest was 1740 at -0.4C

Gosh, Tone, you mean this quotation from your citation?

Period Record Year
Year 6.84 °C (44.31 °F) 1740
Spring (March–May) 5.64 °C (42.15 °F) 1837
Summer (June–August) 13.10 °C (55.58 °F) 1725
Autumn (September–November) 7.49 °C (45.48 °F) 1676
Winter (December–February) −1.17 °C (29.89 °F) 1683/1684

Learn to read before you go all snarky and start accusing me of being wrong, son. That says the coldest winter was 1683, not 1783 … see my graph above, which agrees with Wikipedia about 1683 …


My apologies … i was a century out.
However your article is based on a false premise.
The quoted study was not claiming that Laki was responsible for the winter of 1783/84 … son.

Willis Eschenbach

It appears that not only are you so careless that your claims are 100 years wrong, now you’ve proven that either you can’t read or your don’t care about clarity. So let me remind you of my saying the following:

If you disagree with someone, please QUOTE THE EXACT WORDS YOU DISAGREE WITH, so we can all understand the substance and nature of your objections.

It appears that you think I said that the quoted study claimed that Laki was responsible for the winter of 1783/84 … I quoted exactly what the study said about the temperatures of the winter. I said nothing about whether the study said Laki was responsible or not.
In fact, they said Laki was NOT responsible, which is very unusual among such studies. Most of them claim that Laki was the sole and only cause of the effects on the weather. I assumed that the readers were capable of reading the study and drawing their own conclusions.
Read what I said again, Tone. I never made the claim you think I made.

Bill McCarter

Willis, can you integrate those graphs. It may be that it was colder by number of degree days, not by absolute or average temps. Thx. As always I am pleased by what you do.

Ulric Lyons

Willis said:
“Remembering that the study claimed that this was “among the coldest winters in Central England”, which winter looks like the big winner here?
In fact, far from being among the coldest all-time winters, the winter of 1783-1784 was not even in the top three for the quarter century 1775-1800 …”
As you saying coldest winters and not coldest months, the usual practice is give the average for December, January and February, you should find that it is the second coldest in that 26yrs.
While there are known astronomical causes for the winter of 1783/84, the effects of aerosols and ash from Laki, being low altitude, had the effect of exacerbating the high temperatures through the summer months when they engulfed the UK.

You are right and Willis dead wrong, for whatever reason. I already pointed this out to Willis, but as per usual, he hasn’t bothered to respond.
For the 50 years 1741 to 1790 (onset of the Dalton Minimum), 1783/84 was the coldest three months. And the following winter tied the next coldest of that half century, 1764/65.
Here again is what I wrote above, typically ignored by Willis:
You are mistaken about the CET record. Only one winter in the period you cite was more severe, and it occurred during the Dalton Minimum.
The second and third coldest CET winters during that quarter century were back to back after Laki:
1783/84 – 3.5c…SEVERE
1784/85 – 4.1c…SEVERE
Only 1794/5 was worse.
1794/95 – 1.4c…SEVERE

Willis Eschenbach

Thanks, Ulric. I’ve posted the graph of the winter (DJF) CET upthread.

Again, what counts as “unusual”?
It was the lowest in an ~55 year period, followed by the next lowest winter. The lower winter T of 1704/95, as repeatedly noted, fell during the Dalton Minimum and except for 1739/40, the other two lows were during the Maunder Minimum.
IMO the lowest temperature in a period longer than half a century, followed by another unusually low T winter, is more than “unusual”. Especially when going back another 25 years (1715-39) gets you only one winter colder.
You would benefit from looking at the actual numbers I linked for your benefit, rather than at a graph.
You should also acknowledge that your statement “the winter of 1783 was cold … but according to the CET, it didn’t even make the top three in the quarter century 1775-1800. Hardly impressive” was wrong. As noted over and over again, it was the coldest in that period but one during the Dalton, and it was followed by another which tied for third.

Catherine Ronconi

Sadly, Willis is a recidivist, serial ignorer, as of the hundreds of papers showing the influence of solar activity on climatic phenomena. Going “La-la-la, I can’t read you!” is the anti-scientific method.
As one can see the volcanic eruption DID have a BIG effect on temperatures, although not long in duration.

Catherine Ronconi

Now there’s an instructive graphic.

The chart above and the following below are from Joe D’Aleo of Weatherbell, the best I have ever come across when it comes to climate and why/how it may change..
In North America, the winter of 1784 was the longest and one of the coldest on record. It was the longest period of below-zero temperatures in New England, the largest accumulation of snow in New Jersey, and the longest freezing over of the Chesapeake Bay. There was ice skating in Charleston Harbor, a huge snowstorm hit the south, the Mississippi River froze at New Orleans, and there was ice in the Gulf of Mexico.
The Laki eruption illustrates that low energy, large volume, long duration basaltic eruptions can have climatic impacts greater than large volume explosive silica-rich eruptions. The sulfur contents of basaltic magmas are 10-100 times higher than silica-rich magmas (Palais and Sigurdsson, 1989). The sulfur dioxide is what forms the sulfate aerosols which reflect radiation.
How does sun play a role? I believe the sun drives the oceanic cycles which drive the weather. See the details of how here. Volcanism is the wildcard amplifier. See how the TSI as compiled by Hoyt/Schatten/Willson matches the ocean cycles and temperatures.