Dronning Maud Meets the Little Ice Age

Guest Post by Willis Eschenbach

I have to learn to keep my blood pressure down … this new paper, “Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks“, hereinafter M2012, has me shaking my head. It has gotten favorable reports in the scientific blogs … I don’t see it at all. Anthony provides an overview of the paper here.

First, the authors say:

Here we present precisely dated records of ice-cap growth from Arctic Canada and Iceland showing that LIA summer cold and ice growth began abruptly between 1275 and 1300 AD, followed by a substantial intensification 1430– 1455 AD. Intervals of sudden ice growth coincide with two of the most volcanically perturbed half centuries of the past millennium.

OK, precisely dated records show that big volcanoes equals Little Ice Ages. Peaks in ice growth coincide with volcanoes. Got it. Then in the paper they discuss the later interval of “sudden ice growth”. They start by saying …

The PDF peak [in ice growth] between 1430 and 1455 AD corresponds with a large eruption in 1452 AD …

What’s the problem with these claims? Figure 1, which is from their study with a couple of my annotations, shows the problem …

Figure 1. Original Caption Figure 2. … (b) Global stratospheric sulfate aerosol loadings [Gao et al., 2008]. (c) Ice cap expansion dates based on a composite of 94 Arctic Canada calibrated 14C PDFs (probability distribution functions). I added the vertical red line down from the top of the “D” panel that shows the full size of the sulfates from the eruption in 1258 (258 teragrams [megatonnes]). The vertical blue line, also added, indicates the timing of the following large eruption in 1455.

I get nervous when people cut off important data in a graph, it’s a bad sign regarding their transparency … but I digress …

I always look for alternative ways to verify what the authors are showing. In this case, the GAO et al 2008 aerosol loadings shown in figure 1(B) are calculated loadings using a record of the volcanoes and a climate model. Me, I always prefer actual data. Fortunately, we have very accurate data thanks to the ice core record from a place with the lovely name of Dronning Maud Land. You may not recognize it by its Norwegian name, but when I say “Queen Maud Land”, everyone knows where that is … well, everyone but me, I had to look it up …

Figure 2. Location of Dronning Maud Land, home of ice. And ice cores.

Ice cores record how much sulfate has fallen on the ice during past years. Sulfate comes from volcanoes, and is ejected high into the stratosphere. From there it is mixed worldwide, and eventually it settles out on the ice. The sulfate record from two different ice cores in Dronning Maud Land agree to within a couple of years, so we can have confidence that they are accurate.

Next, before I go further, what is the “probability density function (PDF)” that the paper uses? It is a function that gives the probability of an event occurring in a certain year. For example, carbon-14 dating of some dead moss might give the date it died as say 1135. Are we sure it died in exactly 1135? No way, that’s just the most probable value. It might have died in 1134, or 1136. It might also have died in 1130 or 1140, but the probability of it being either of those years is much lower than the probability that the date is actually 1135. The probability density function is the function that gives us the probability of the event actually occurring in each years. Typically it looks like the famous “bell curve” or Gaussian curve, peaked in the middle and fading to zero on either side. It may be asymmetrical, with different probabilities that the event is before or after the most probable date. It is a good way to aggregate data

With that as prologue, here is the overview of the two records. One is the ice expansion record from the M2012 paper. The other is the volcanic sulfate record from the Maud Dronning Land ice cores.

Figure 3. Volcanic sulfate records from Maud Dronning Land (blue and green) and the ice cap expansion records from Baffin Island (purple line). The PDF values are the probability percentages multiplied by 100, so for example if the scale reads “400” that means 40% (0.40).

Right away you can see some curious things. There is a large expansion of the ice cap (increasing purple line) in the century from 900 to 1000, but nary a volcano in sight. They say in the paper that “cold summers can be maintained by sea-ice/ocean feedbacks long after volcanic aerosols are removed …”, but what started and maintained the cold summers from 900 to 1000?

Then there’s the claim that the intervals of sudden ice growth in 1280 and 1435 occur during “two of the most volcanically perturbed half centuries of the past millennium” … I’ll buy that for the year 1280, but 1435? One lousy volcano in the half century around 1435, it wasn’t even as “volcanically perturbed” as the last half of the 20th century or the first half of the 19th century.

Intrigued by these problems with their claims, I looked closer. Figure 4 shows a closeup of the time in question:

Figure 4. As in Figure 3, volcanic sulfate records from Maud Dronning Land (blue and green) and the ice cap expansion records from Baffin Island (purple line).

More oddities. First, the expansion of the ice cap started in 1215, about 45 years before the eruption in 1258. Then in 1250, the rate of ice cap expansion increased, almost a decade before the eruption. And while you would expect an immediate increase in the rate of ice cap expansion, the increase doesn’t begin until about [1470].

But that’s nothing compared to the other end of the period. The peak ice cap expansion occurs in 1435, a full two decades before the eruption in [1455]. Nor does the eruption speed up the ice cap expansion. In fact, the expansion slows markedly after the 1455 eruption.

Now, you may recall that I quoted the start of a sentence above, which said:

The PDF peak between 1430 and 1455 AD corresponds with a large eruption in 1452 AD …

Um … well … they are being most expansive with their claim that the 1435 peak and the eruption “correspond”. The volcano is well after the expansion in ice area. How do they explain this?

Well, the sentence goes on to say:

… although the ages of the three largest 5-year bins appear to precede the eruption date. In contrast to the earlier 13th Century peak, the second PDF peak occurs at the end of a 150-year interval of variable but falling snowline (Figure 2c), raising the possibility that the PDF peak plausibly reflects a brief natural episode of summer cold that preceded the large 1452 AD eruption. Alternatively, the apparent lead of kill dates with respect to the 1452 eruption may be a consequence of combined measurement and calibration uncertainties.

To me, that’s special pleading. Not only that, but it destroys their entire case. Here’s why:

If the 1435 peak “plausibly reflects a brief natural episode”, then why should we believe the much smaller 1280 peak is not just another “brief natural episode”?

Alternatively, if the timing of their “precisely dated” 1435 record is really off by twenty years due to “combined measurement and calibration uncertainties”, then why on earth should we believe the timing of the “precisely dated” 1280 peak?

I’m sorry, but I just don’t see the evidence that volcanoes had anything to do with the changes in the Baffin Island ice cap. And their whole sea/ice feedback claim? I note that the claim is supported by … well … I fear all it is supported by is models all the way down.

w.

PS—An oddity. The 1258 volcanic eruption was the largest in the last 2,000 years … and as far as I can determine, nobody knows where it occurred.

DATA: All data used in this post is available here as a comma-separated (CSV) file.

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Sera

Um … well … they are being most expansive with their claim that the 1435 peak and the eruption “correspond”. The volcano is well after the eruption. How do they explain this?
Typo: The volcano is well after the eruption?
[Reply] Thanks, fixed. -w.]

Sera

Could it have been this eruption in China @ 1200?
http://www.springerlink.com/content/4745p18767535574/

Ed Fix

In otherwords, they present two ice growth spurts that don’t quite line up with volcanic events, and they invent two ad hoc explanations to shoehorn the data into their hypothesis. Unconvincing at best.

Nylo

Excellent as usual, Willis.

Mike Jowsey

Hi Willis – thanks for another logical evisceration of dodgy science. I noted a few typos – hate to be the pedant, but here goes…
And while you would expect an immediate increase in the rate of ice cap expansion, the increase doesn’t begin until about 1670.
The date 1670 should be 1270?
The volcano is well after the eruption.
The peak is well after the eruption?
The peak ice cap expansion occurs in 1435, a full two decades before the eruption in 1655.
1655 s/b 1455?
Cheers

braddles

What are these references to the 1600s? Perhaps you need a proofreader.

sophocles

Couldn’t possibly have been the sun—with the Wolf minimum from 1280 to1350, the Sporer Minimum from 1460 to 1550 and the Maunder Minimum from 1645 to 1715. The sun may have taken 2 sunspot cycles to slide into the minimum much as it seems to be doing at present, which could explain the early rise in sea ice.
Seems a better fit than volcanoes. The geo-chemical record should show the GCR flux by-products.
Although what happened with the ice during the Maunder minimum? History records European mountain glacier growth with several rapid increases during those times right up to 1730.

bernie1815

Willis:
Outstanding. Assuming the dating of the QML ice cores is reliable, this paper is thoroughly debunked. Surely the reviewers should have caught this? Have you sent your critique to the authors?

Allan MacRae

Thank you Willis.
But why use real data when you can assume fabricated data?
You can “prove” anything you want with fabricated data, and never have a failed hypothesis, and always get published in the “top” journals, in this brave new world of science.
The warmist approach could also apply to engineering: “Assume a bridge. Now drive over it.”
OK – this is nonsense – but it’s already being done in Western Europe and Ontario, where subsidized wind and solar power are damaging electrical grid security and supply.
It really IS that absurd.
“Stupid is as stupid does.”
– Forrest Gump

Jim Melton

Well spotted Willis,
It’s all (post)normal;
Coincidence = Causation
Cherry picked data = Global truth
Agenda driven science = Anything to prop-up ‘the cause’
ps I think you have a couple of typos of dates under the last graph.

Paul Mackey

There are a few numerical typo in here, eg
“occurs in 1435, a full two decades before the eruption in 1655”

Bob Shapiro

And, why was it that the eruption just after 1800 didn’t cause ice eruption?

Bob Shapiro

I mean ice expansion.

richardscourtney

Willis:
Brilliant again! Thankyou.
Sadly, I think we can expect much more of such trash as Rio+20 nears. Two such papers this week and many more to come (sigh).
Richard

Oldjim

Out of interest – since I don’t know – would the fact that the sulphate records are from the antarctic and the paper is based upon the arctic be of any relevance. I wonder about the movement of sulphates between the two hemispheres – rate and uniformity

D Nash

Hey Willis,
Had the same thoughts myself. Couple of typos:
The peak ice cap expansion occurs in 1435, a full two decades before the eruption in 1655 (should be 1455).
The volcano is well after the eruption – assuming that the eruption is well after the peak.

Gail Combs

The Mysterious Missing Eruption of 1258 A.D. by Erik Klemetti, assistant professor of Geosciences at Denison University.
A closer look at that missing eruption.

Willis…I am really glad that you make time for this kind of detailed critical review…I fear no one of those scientists who publish in the literature will do so (there is little motivation when most will readily accept it – otherwise they have to look more closely at the natural warming and cooling events). The pity is that there is then no record of criticism in the published literature and this bad science is all that students will have to refer to…unless science institutions embrace blogging realities! If you had time for a little note to the journal….

John S

“The peak ice cap expansion occurs in 1435, a full two decades before the eruption in 1655.”
Typo?

JCWToronto

In para after figure 4 “the increase doesn’t begin until about 1670.” Imagine should read 1270. Similarly next para “1435, a full two decades before the eruption in 1655” must be 1255.

Bill Marsh

Willis,
It seems to me that there is a trend emerging with the last few papers is to attempt to disregard or downplay the use of Antarctic ice cores as a temperature proxy and/or atmospheric content measure. I’m not sure, but I suspect, that is because the ice cores aren’t telling the story ‘The team’ wants to hear. I find that more disturbing than selective omission of data because it is inconvenient to your proposed findings.

gator69

This would not have passed a fifth grade peer review. Slight correlation now proves causation?

Anopheles

I am shocked that no-one can see how ice causes volcanoes from this data.

Greg

People gave me money to do a study to prove something. My study failed utterly. I would never receive money to do anything again any time soon, therefore I wrote up a paper anyway. The new science.

I looked at this last night and wasn’t convinced
http://www.vukcevic.talktalk.net/volcano-LIA.htm
but than I am biased, since for period where there are the actual data available and not based on proxies I have different idea why the Northern Hemisphere came out of the Little Ice Age and the subsequent warming
http://www.vukcevic.talktalk.net/GTCa.htm
and therefore it is possible to speculate that reason for going into the LIA is reversed, and it is not the volcanic sulfate.

nice discussion of the missing eruption here
http://www.wired.com/wiredscience/2012/02/the-mysterious-missing-eruption-of-1258-a-d/
it even quotes a Mannian paper (2012)

I noticed that as well. Cause has to precede effect, not that such pesky details seem to bother climate science.
One issue here is, how good a proxy for the climate effects of volcanoes is SO2? An SO2 spike in the core is a sure sign a volcanic eruption occured but the climate effect is largely extrapolation from 2 recent eruptions (Pinatuba and El Chico) or if you prefer guesswork. We really don’t know if climate effect is proportional to SO2 content.

ferdberple

If anything, the data shows that ice causes volcanoes.
It has been observed that volcanoes and earthquakes increase at times of planetary alignment. Clearly the earth’s climate regulates the orbit of the planets.

ferdberple

Why should cause and effect be a problem in climate science? Gore didn’t let the lag between temperature and CO2 influence his results. He and the IPCC got the Nobel for proving that temperature causes CO2.

Rob Crawford

When did science overturn causality?

J.Hansford

Typos… 1655 and 1670…. Should be 1455 and 1470.
[Fixed. Thank you, and the others who helped proof this. Robt]

David in Georgia

Wait a minute! How many times has a Climate Scientist (TM) or a Global Warming advocate told us that the Little Ice Age was purely a regional thing and did not reflet a global change in temperature? Now that they have a partial explanation for it volcanoes caused measurable ice cap expansion affecting at least half of the globe?
If volcanoes caused a decrease in temperature enough to cause dozens of decades of ice growth, then it would follow that before that ice growth (and before the volcanoes) the temperature had to be higher that after the volcanoes. Therefore, the temperature during the LIA was cooler than the previous temperatures, enough to cause rapid growth of ice.
So, once the effects of that cooling have subsided enough, melting of that ice is natural, and not due to CO2. If this paper has any validity at all, it can be used to show that our current warming is not only natural, but merely a return to pre-LIA temperatures.

ferdberple

It has been observed that volcanic hotspots often occur in antipodal pairs, suggesting that oceanic meteor impacts are one possible cause. A novel mechanism by which orbital mechanics influences climate?
http://www.sciencedirect.com/science/article/pii/S0012821X05001226

ferdberple

Rob Crawford says:
April 13, 2012 at 6:07 am
When did science overturn causality?
When it conflicts with Political Correctness. Science that shows politically incorrect conclusions is heavily censored and de-funded.

Colin Porter

I know that we have crossed swords in the past Willis, but I too am very much with you on this one and likewise I am trying to control my blood pressure.
Your analysis concentrated mainly on the first part of the argument regarding correlation of LIA to volcanism. As with other areas of climate science, they seem to require a heavy dose of positive feedback in order to justify their theories. In this case, volcanic activity by itself can only perturb the climate for a small number of years and to justify extending it for the duration of the LIA, which incidentally did not exist anyway because I know a Mann who says so, the concept of a large positive feedback must be invoked via increased albido from more extensive sea ice cover. But is this really possible? After all, this sea ice albido is patently incapable of supporting the existing sea ice through the summer months as it looses 50% or more of its area/extent in summer. And if the sea ice does extend initially due to volcanic aerosol activity, then the increased sea ice is going to be moderated by virtue of the fact that the lower latitudinal ice will be much more susceptible to disappearing from a higher insolation of the sun and from warmer oceans at that latitude. i.e. yet again negative feedback moderating climate.
Perhaps you may like to find time in the future to lay the ghost of the overstated influence of high latitude ice on albedo.

Nice refutation and falsification of their paper Willis. Keep up with your explosive slicing and dicing. You’re the paper shredder! [;)]

Kasuha

Erm… that PDF thingy… it seems to be labeled “KILL RATE (arbitrary units)” in very similar graph in Roger Pielke’s Sr.’s post from a few days ago. And it is connected somehow to land ice extent, measuring how much of vegetation died at that period. And there’s another graph showing sea ice (with another arbitrary units) which has very different peaks, which somehow seem to follow both eruptions quite nicely with a little delay.
http://pielkeclimatesci.wordpress.com/2012/04/12/new-physics-today-article-the-triggering-and-persistence-of-the-little-ice-age-by-bertram-m-schwarzschild/
Now, vegetation death rate changes may have many reasons, and speed of land ice growth may be just one of them. Personally I wouldn’t take either of the two peaks as too important as it’s the area below the curve which tells us total amount of deaths and here the area between the two peaks is much more important than the peaks themselves. And after the second peak, the death rate likely diminished because there was too little to die left.
The graph basically tells us that at about 1280 the land ice started to grow until about 1435 when all of the examined land was already covered by ice. The temperature graph corresponds to that, too.

John Blake

Anyone citing “models” –the more, the faster, and the worse– is ipso facto guilty of circular reasoning, false pleading via argumentum ad verecundiam.
Refutation at length and in detail is good to put on-record, but
let’s face it: Whater their mutual-admiration credentialism, such ad hoc vs. empirical exegeses are not just academically misleading but worthless on their face.
Better to simply construct a checklist of standard fallacies and rate these endlessly repetitive exercises in grant-esque futility on a 10-point scale accordingly.

oMan

Willis: thanks, another tight grouping in the ten-ring. In light of your analysis, their argument reads like a “just so” bedtime tale.

Pamela Gray

They make the same mistake all wriggle matchers do. No plausable mechanism regardless of what came first, the chicken or the egg. I swear, if I really worked at it and got me some of that algore funding, I could convince learn-ed Ph.D. types of folk that my never-fail rising at 5:00 AM MUST be the cause of day. Won’t go into the cause of night.

oMan

Folks: may I offer a suggestion as to one reason why the warmist arguments have so much power? The Mercator projection combined with sparse sampling in high (especially northern) latitudes combined further with fancy interpolation. The result is that a few “hot” numbers from 85 degrees north becomes a proxy for the whole Arctic, and then shown in blazing red on a graphic which assigns far too much psychological weight to the vanishingly-small regions of the globe. We are wired to pay attention to that color and that visual overemphasis. And these people keep playing us with it. Can we try to correct for that, with different projections? With a 90 degree rotation of the lat/long grid just to show the viewer what that does to all the red versus green and blue on the fright maps?

MarciaF

“Abrupt onset of volcanism triggered by the Little Ice Age.”
There, I fixed it.

Bill Illis

The GISP2 Greenland ice core volcanic sulfates goes back 110,000 years so we can check to see if big volcanoes always result in Little Ice Ages.
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/chem/volcano.txt
The Holocene and the transition out of the last Ice Age had many very large volcanoes. Many are twice as large as the 1258 event or four times Tambora. Not much of an impact against the trends.
http://img526.imageshack.us/img526/8149/transliavolcanoes.png

jayhd

Did these researchers use Mr. Peabody’s Way-Back machine to “precisely” date the records of ice cap growth?
Jay Davis

Thanks Willis, good article.

Doug Proctor

Is it possible that the internet, blogging and, for the first time, a large number of non-academic, but technically proficient readers, are revealing how much shoddy scientific work has always been published?
I’m suspicious that the pressure to publish (justification for grants in our policy-pertinent period) is just making obvious what few knew all along.

Typo. Talking about the rate of ice cap expansion around the 1258 eruption Willis writes: “And while you would expect an immediate increase in the rate of ice cap expansion, the increase doesn’t begin until about [1470].”
Seems that should be 1270.

You can’t “precisely date” ice cores. Tree rings are annual rings, ice core rings are not. It snows all year round in the Arctic and Antarctic.

John

Willis, this was excellent. You can’t claim causality if the cooling precedes the volcano.
One thing though, about strength of volcanos. The last half of the 20th C, if my calculations are correct, was pretty low, relative to the 13th and 15th C, in terms of Tg of sulfur emitted. I calculate that Pinatubo released about 9 Tg of sulfur (20 million tons of SO2). On Fig. 1 above, Krakatoa looks to be around 20 Tg of sulfur (1883), about twice Pinatubo in the same graphic, and the earlier, larger Tambora (1815) looks to have emitted about 120 Tg of sulfur. Tambora is the volcano that created the Year without a Summer in New England, which caused the migration from New England to the Ohio valley. The Year without a Summer also caused considerable starvation in Europe. Pinatubo appears to be the largest emitter of sulfur in the 20th C, so the 20th C is pretty low in vulcanism, using SO2 (sulfur) as the metric of measurement, relative to most centuries in the millenium.
The 1280 volcano emitted 258 Tg of sulfur, over ten times what Krakatoa emitted, and just over double what Tambora emitted. Just that one volcano appears to make the 13th C more volcanic than any of the other centuries on the chart. The 1435 volcano emitted about 150 Tg of sulfur, but that one volcano doesn’t seem to be enough to make the 15th C more volcanic than the 19th, but it is still quite large by historical standards, about 15 times more SO2 emissions than Pinatubo.
What does this mean? I like the interpretation found in the Wikipedia entry for the Year without a Summer. Causality for the crop-killing freezing temps in both Europe and New England is jointly attributed to both very low solar activity (Daulton minimum) and the cooling effects of Tambora.
Similarly, didn’t we also have a cooling sun after circa 1300, leading down to the Maunder Minimum? It seems to me that volcanism of this magnitude (258 and 150 Tg sulfur, vs. about 9 for Pinatubo) could add to a cooling process already underway, as Tambora appears to have done.
In other words, the actual story (as posited herein) was that natural forces were already producing cooling, and volcanism added to that. But this story wasn’t good enough, you had to get rid of natural forces producing cooling (just as David Deming relates that an IPCC person in the mid 1990s told he that they had to get rid of the Medieval Warm period.) So the authors morphed interesting science (really big volcanos enhanced cooling process already underway) to a more politically correct but scientifically wrong story, e.g. that volcanos CAUSED the cooling. Once again, science is twisted to serve politics.
At least they’ll get their grants the next few years!

Arno Arrak

If this proves anything it is that volcanic eruptions just don’t measure up to their reputation. I have come to the conclusion that volcanic cooling that is supposed to follow an eruption and have an influence on climate simply does not exist. Part of it is due to ignorance of the fact that all climate graphs at all times are full of El Nino peaks and La Nina valleys in between. Those are the spikes they try to eliminate by their running averages. It so happens that when a volcano erupts when an El Nino has just peaked and a La Nina valley is beginning to form that La Nina valley is recruited as an example of volcanic cooling happening. Two examples of this are Mount Pinatubo and Gunung Agung. On the other hand, when the eruption takes place when the La Nina has bottomed out and the next El Nino is just beginning the expected cooling is simply absent and nobody has any idea where it went. El Chichon in Mexico is an example of that. Whether a cooling can be observed after any particular eruption thus depends upon the timing of the eruption with respect to the location of neighboring El Nino and LacNina phases of ENSO. This of course is contrary to claims that volcanic cooling can ovecome El Nino warming as so-called “experts” have been telling us. For more info read pages 17-21 in “What Warming?”