Dr. Roger Pielke Sr. writes on his blog today:
Every once in a while. a nugget of new research insight appears that adds to our understanding of the climate system, and its complexity. One article of this type has appeared.
Miller, G. H., et al. (2012), Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks, Geophys. Res. Lett.,39,L02708,doi:10.1029/2011GL050168
The Miller et al article is also at Physics Today, and is paywalled, but with an interesting title:
The triggering and persistence of the Little Ice Age with this even more interesting subtitle:
“A mere half century of volcanism seems to have initiated a chill lasting half a millennium”.
The key points from GRL are:
- Little Ice Age began abruptly in two steps
- Decadally paced explosive volcanism can explain the onset
- A sea-ice/ocean feedback can sustain the abrupt cooling
Abstract:
Northern Hemisphere summer temperatures over the past 8000 years have been paced by the slow decrease in summer insolation resulting from the precession of the equinoxes. However, the causes of superposed century-scale cold summer anomalies, of which the Little Ice Age (LIA) is the most extreme, remain debated, largely because the natural forcings are either weak or, in the case of volcanism, short lived. 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. A transient climate model simulation shows that explosive volcanism produces abrupt summer cooling at these times, and that cold summers can be maintained by sea-ice/ocean feedbacks long after volcanic aerosols are removed.
Our results suggest that the onset of the LIA can be linked to an unusual 50-year-long episode with four large sulfur-rich explosive eruptions, each with global sulfate loading >60 Tg. The persistence of cold summers is best explained by consequent sea-ice/ocean feedbacks during a hemispheric summer insolation minimum; large changes in solar irradiance are not required.
Here’s one of the figures via GRL:
h/t to Bill Yarber
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It’s a model, one that raises more questions than it answers.
Yes this paper was disccused on WUWT last January and as “Schroder” points out via his link http://www.wired.com/wiredscience/2012/01/volcanoes-and-the-little-ice-age-not-the-smoking-gun/
Miller et al have cooked the books in what amounts to a pathetic display of pal review by the so called reviewers.
This paper should be exposed as a sham supporting AWG and not a reliable scientific document. Miller has used the world sulfur dioxide record instead of the northern hemisphere record to support his views. If the southern hemisphere volcanoes do not show up in the northern hemishere record how can they affect moss growth?? When looking at the northern hemisphere record in isolation the Miller et al claims look very weak.
Why wasnt this picked up in peer review?
OT…is anyone else using modzilla and XP having trouble with the comment window in wordpress blogs? I have to press enter to display the full size text box and the spell checker has gone.
In chrome. I’m getting similar problems with the comment text box full size. Have been for about a week.
rgb.
Robert, a few conversations I had with the late Jan Pompe centred around the possibility that there might be a correlation between low Solar activity and volcanism. We never reached a conclusion unfortunately.
Sea Ice. Jan and I also discussed this. I posited here a few years back that a reduction in sea ice would be a negative feedback. My posit then and now is that due to the low incidence at minimum, the albedo change would be minimal. The loss of energy from open water would be huge.
Now a rant obout terminology. People talk about precession when what they really mean is nutation. Do your gyroscopic physics folks!
Incidentally. When nutation becomes too large, A gyro will topple, wonder if that has ever happened before!
DaveE.
OT…is anyone else using modzilla and XP having trouble with the comment window in wordpress blogs? I have to press enter to display the full size text box and the spell checker has gone.
^^^ Yes, but it seems fine with Moz+Ubuntu. Weird.
Joe Zarg says:
April 12, 2012 at 1:01 pm
“Northern Hemisphere summer temperatures over the past 8000 years have been paced by the slow decrease in summer insolation resulting from the precession of the equinoxes.”
Can somebody explain that, because it doesn’t make sense to me…..
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Try this website with good animation illustrating Obliquity, Eccentricity, and Precession: http://www.sciencecourseware.org/eec/GlobalWarming/Tutorials/Milankovitch/
or this for a written explanation: http://www.indiana.edu/~geol105/images/gaia_chapter_4/milankovitch.htm
Further reading: (New info) http://motls.blogspot.com/2010/07/in-defense-of-milankovitch-by-gerard.html
Aha! I knew the Earth’s temperature was self-regulating, since we now know (hey I read it in The Telegraph) that climate change causes volcanoes to erupts.
http://www.telegraph.co.uk/earth/environment/climatechange/7604188/Volcanic-ash-cloud-Global-warming-may-trigger-more-volcanoes.html
See? Warming = volcanoes = cooling…now we just have to wait.
John M says:
April 12, 2012 at 6:28 pm
Aha! I knew the Earth’s temperature was self-regulating, since we now know (hey I read it in The Telegraph) that climate change causes volcanoes to erupts.
http://www.telegraph.co.uk/earth/environment/climatechange/7604188/Volcanic-ash-cloud-Global-warming-may-trigger-more-volcanoes.html
See? Warming = volcanoes = cooling…now we just have to wait.
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But maybe not for long….
However it has been quiet recently: http://en.vedur.is/earthquakes-and-volcanism/earthquakes/
The Little Ice Age did indeed begin suddenly, but it had multiple phases (at least 5). All of these phases seem to be related to the same causal mechanism and correlate exactly with solar events (Sporer Minimum, Maunder Minimum, Dalton Minimum, 1880-1915 Minimum, 1945-1977 minimum). One episode of volcanism doesn’t prove anything–explosive volcanic eruptions are common occurences and most are associated with only a year or two of cooling. Hence, volcanic eruptions are not likely suspects for prolonged or repeated cooling. All 5 of the cold phases of the Little Ice Age are not related to unusual volcanic activity. Correlating some volcanic eruptions with cooling doesn’t prove the cooling was caused by the volcanic activity. If you like correlations, the excellent correlation of cooling with solar events is a much better match. Sorry–volcanism won’t do the job.
Obvious question, I suppose, but are the 4 eruptions identified in the paper & are they independently confirmed by other studies ???
Don Easterbrook cites real world empirical data to support a robust explanation of the cause of the LIA. In contrast, Pielke Snr cites a study that uses a model that proposes a different causal explanation – one that Don points-out actually doesn’t fit with historical pattern of the LIA.
This might be an opportunity for readers to self-assess whether they might be prone to inexplicable outbursts of politically-motivated alarmism.
Q. Which of the following do you consider is likely to provide a better causal explanation of an observed phenomenon in the real physical world:
a) a model of reality which doesn’t correspond with the observed pattern of the phenomenon in question?
or
b) data from the real physical world which does correlate with the observed pattern of the phenomenon in question?
Geoff Sharp (April 12, 2012 at 5:14 pm) asked:
“Why wasnt this picked up in peer review?”
You have faith in peer review?
By nature it’s socially corrupt.
When no one’s qualified to supervise:
http://en.wikipedia.org/wiki/Peter_Principle
Don Easterbrook (April 12, 2012 at 7:17 pm) concisely asserted:
“Sorry–volcanism won’t do the job.”
Agree (but the baseball bat will convince many to “see” otherwise).
robert barclay says:
April 12, 2012 at 8:49 am
The ocean ignores the second law of thermodynamics.
Don’t be silly.
The key thing with snow-ice cover will be how long it lasts into the summer. The albedo effect can only be strong for as long as the snow-ice remains.
If big volcanoes produce ‘summers without summers’ (1816 apparently did), then the argument is logical.
Does scientific archaelogy yet have the ability to identify cooler summers without necessarily having colder winters? That might be a key thing to investigate…….
Jeff L says:
April 12, 2012 at 8:16 pm
Obvious question, I suppose, but are the 4 eruptions identified in the paper & are they independently confirmed by other studies ???
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An Article about this paper discusses that issue. Volcanoes and the Little Ice Age: Not the Smoking Gun? by EriK Klemetti.
“Erik Klemetti is an assistant professor of Geosciences at Denison University. His passion in geology is volcanoes, and he has studied them all over the world.”
The most powerful physical process which controls global climate is overturning ocean circulation, because it works like heat pump cooling the ocean and heating atmosphere. And intensity of this circulation is critically controlled by sinking of warm salty waters at the rim of marine ice near Greenland. Forming of near-bottom return current depends on details of sea bottom topography at sinking site, so the position of this rim is of primary importance for intensity of overturning circulation and heat balance between ocean and atmosphere. This establishes a positive feedback loop: slowing down of overturning circulation cools Arctic basin first and leads to sea ice expansion which slows down the circulation even more. All other forcings – cloud cover, orbital wobbling, snow-ice cover or volcanism – work only through this amplification mechanism, which, being based on positive feedback, provides also natural oscillatory behavior at different time scales, that is, auto-oscillations which can be phase-locked with external periodical forcings. Many different forcing mechanisms can be involved, but it always necessary to remember that they apply to a system which is inherently unstable and can powerfully amplify their effects by natural predilection for oscillations.
Geoff Sharp (April 12, 2012 at 5:14 pm) asked:
“Why wasnt this picked up in peer review?”
___________________
Paul Vaughan says: @ur momisugly April 12, 2012 at 10:10 pm
You have faith in peer review?
By nature it’s socially corrupt.
When no one’s qualified to supervise:
http://en.wikipedia.org/wiki/Peter_Principle
_____________________________
Here is an even better example of the problem.
An Article on scientist falsifying data in Scientific American declaring there is no real problem acording to a “study” done by the vice provost of Caltech.
So how does this hand wavy “Study” published in Scientific American stack up against actual surveys?
Of course the Climategate e-mails and the experiences of scientists show journals now run according to “Pal-Review”
EXAMPLES:
2003: Michael Mann on what “the community” should do to punish a journal that dared to print dissenting views on the climate hoax and
2007 Mann email to Phil Jones: “I have a top lawyer already representing me…Wei Chyung needs to sue them, or at the least threaten a lawsuit…The threat of a lawsuit alone my prevent them from publishing this paper, so time is of the essence” There is lots more interesting stuff at Over 250 noteworthy Climategate 2.0 emails
It is not a case of either/or. Solar forcings do exist, and sulfates in the atmosphere (or lack of them) can be effected by the solar forcings.
We need to think about both sunbeams and volcanoes, and likely other factors as well, including the small influence of CO2.
Furthermore, we need to play about with the simple fact each action creates a reaction. Think of it in terms of water sloshing in a bathtub. As a small child, I could irritate my parents by timing the movement of my butt in such a manner as to generate a super-slosh. In the same manner, two large volcanoes five years apart might have a very different effect from two volcanoes of the exact same size seven years apart.
Great science is done in bathtubs, you know.
Dr. Iben Browning wrote and lectured on volcanoes and climate for decades. He made the Little Ice Age connection years ago. His daughter now has a newletter on the subject. He gave very interesting lectures. His book is called “Climate and the Affairs of Men.”
@Sergey (April 13, 2012 at 1:52 am)
Wind’s more primal.
It’s role in evaporation and mixing can’t be ignored.
It’s driven by temperature _gradients_.
Sensible climate narratives must be consistent with Earth Orientation Parameter (EOP) records.
—
Climatologists NEED to VERY CAREFULLY learn how to use EOP to trim by orders of magnitude the set of permissible model states.
robert barclay says: April 12, 2012 at 8:49 am
“Surface tension blocks heat and is the key to the climate on this planet. The only energy that goes into the ocean goes in via the sun’s rays. The ocean ignores the second law of thermodynamics.”
Robert, this makes no sense, particularly the last statement.
Yeah, I already pointed this out in another thread — it almost looks like he’s cut and pasting a paragraph from a third place. The ocean, like everything else, obeys all of the laws of thermodynamics and surface tension has virtually no effect on heat transmission and is utterly irrelevant to the Earth’s climate. It is true that most of the heat that goes into the upper ocean goes in via the Sun’s rays, although I’m certain that there is a steady outflow from the Earth’s interior at the bottom that is low in intensity (power per unit area) but high in aggregate power and at least a moderate amount of heat exchange at the surface from conduction and infalling latent heat, e.g. a warm rain on a colder sea.
But asserting that anything violates the second law just makes it instantly clear that the speaker or writer is a nut. It gives climate skeptics in general a bad name, even though most of us are actually sane and know better.
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Try this website with good animation illustrating Obliquity, Eccentricity, and Precession: http://www.sciencecourseware.org/eec/GlobalWarming/Tutorials/Milankovitch/
Although I’m already familiar with the idea, I visited this to see if something had changed. It hadn’t. To be honest, the correlation of any subset of precession, obliquity, and orbital resonance with climate sucks. The best that can be said of it is that orbital resonance kind of works for the last 600,000 years (but utterly fails for earlier periods) and some combination of obliquity and precession sort of works before that for a while (but utterly fails now or still earlier) and that before that, there isn’t any correlation at all between these cycles and either the general depression of the global mean temperature that started some 5 million years ago or the “fluctuation noise” around this mean temperature.
Yes, there are probably some resonant amplifications in the fourier spectrum of the noise associated with the period. No, they do not appear to make a particularly good explanation of why the Earth was 2 K warmer 5 million years ago than it is in the present, why that temperature at first gradually, then much more rapidly decreased by some 8 K, then stabilized some 6K cooler than the present but with geologically brief excursions up 6 K (to the present warm interglacial temperatures) and nearly catastrophically deadly and equally brief excursions down by up to 4K (to where atmospheric CO_2 comes very close to reaching the lower boundary of sustaining plant life outside of the ocean).
At least I have yet to see it. Personally, I think this explanation sucks. The best it can do is suggest that Milankovitch is capable of acting as a resonant trigger between states that are stabilized by something else, with the mean temperature in the cold phase in particular having nothing to do with orbital resonances, precessions, or obliquity per se.
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So, are you going to change your tag to “Archimedes”?
😉
/9-p