Rapid climate changes in the younger Dryas, but with a 120 year time lag

From GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre

Regional climate changes can be very rapid. A German-British team of geoscientists now reports that such a rapid climate change occurred in different regions with a time difference of 120 years. Investigation in the west German Eifel region and in southern Norway demonstrated that at the end of the last glaciation about 12,240 years before present climate became warmer, first recognised in the Eifel region and 120 years later in southern Norway. Nonetheless, the warming was equally rapid in both regions.

The team around Christine Lane (Oxford University) and Achim Brauer from the GFZ German Research Centre for Geosciences reports in the latest volume of “Geology” (vol 41, no 12, p. 1251) that within the younger Dryas, the last about 1100-year long cold phase at the end of the last ice age, a rapid warming first was measured in the Eifel region. Sediment cores from the Meerfelder Maar lake depict a typical deposition pattern, which was also found in the sediments of Lake Krakenes in southern Norway, but with a time lag of 120 years.  

But how did the researcher revealed such a accurate time marking? “12 140 years ago a major eruption of the Katla volcano occurred on Iceland” explains Achim Brauer. “The volcanic ash was distributed by strong winds over large parts of northern and central Europe and we can find them with new technologies as tine ash particles in the sediment deposits of lakes. Through counting of annual bands in these sediments we could precisely determine the age of this volcanic ash.” Therefore, this ash material reflects a distinct time marker in the sediments of the lakes in the Eifel and in Norway.

Furthermore, lake sediments are very accurate climate archives, especially when they contain seasonal bands similar like tree rings. “It is a diligent piece of work to count and analyse thousands of these thin layers under the microscope to reconstruct climate year-by-year far back in time”, illustrates Brauer.

The ash of the Katla volcanic eruption thus was deposited at the same time in the Eifel and in Norway. The sediments of the Eifel maar lake depict the rapid warming 100 years before the volcanic ash, while it is seen in the southern Norwegian lake sediment 20 years after the volcanic eruption. The same warming, but with a 120 difference in timing between the about 1200 km distant locations? Achim Brauer:

“We can explain this difference with the shift of hemispheric wind systems. Climate changed in both regions very rapid, but the polar front, that is the atmospheric boundary layer between cold polar air and the warmer air of the mid-latitudes, required more than 100 years to retreat from its glacial position at about the location of the Eifel at 50° N to its southern Norwegian position at 62° N.”

Hence, the study provides evidence for a rapid change that slowly moved northwards. The result of this study has some implications on the understanding of both past and future climate change. The assumption of an everywhere and always synchronously changing climate must be questioned and climate models have to better consider such regional aspects.

###

C.S. Lane, A. Brauer, S.P.E. Blockley, P. Dulski: “Volcanic ash reveals a time-transgressive abrupt climate change during the Younger Dryas”, Geology v. 41, no. 12, p. 1251 December 2013; doi:10.1130/G34867.1

Photos of the Meerfelder Maar and of lake drilling can be found here: http://www.gfz-potsdam.de/medien-kommunikation/bildarchiv/klimaforschung/warvenchronologie/

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timetochooseagain
December 4, 2013 9:55 am

There’s a low frequency “stadium wave” for you.

DHR
December 4, 2013 10:04 am

There must have been a large temperature gradient along that 1,200 Km span leading to some very violent weather.

Bruce Cobb
December 4, 2013 10:08 am

Nothing new, except maybe a new straw for them to clutch at in an attempt to save their failed models.

Mike Bromley the Kurd
December 4, 2013 10:10 am

DHR says:
December 4, 2013 at 10:04 am
There must have been a large temperature gradient along that 1,200 Km span leading to some very violent weather.
Superstorm CroMagnon must have been a bugger on the Stonehenge waterfront.

Jquip
December 4, 2013 10:17 am

I have a feeling that it will get lost in the noise: But what they’re stating is that ‘rapid’ climate change is dependent on the atmospheric convection cells. (Polar/Ferrel/Hadley.) eg. Following the CAGW hypo, then at what ppm of CO2 will we find the widths of each cell doing what?
Hint: The models don’t deal with convection in any reasonable manner.

NZ Willy
December 4, 2013 10:17 am

So they’re using the Katla eruption as a chronological synchronizer, but the 120yr discrepancy raises the idea that there may have been another eruption 120yr later — maybe even from the same volcano. Prevailing wind patterns could have blown the ash of one eruption in one direction, and of the other eruption in the other direction. Check your assumptions, I say to them.

tumpy
December 4, 2013 10:31 am

What if one area was still glaciated at the time of the eruption and it then took much longer for the sediment to enter the lake? Sure they cant be accounting for everything!

Owen in GA
December 4, 2013 10:32 am

I wonder if they cross checked the ash assumption with carbon dating of any pollen in the layers immediately above and below the ash layer?

John, UK
December 4, 2013 10:37 am

Perhaps there is a chemical signature in individual eruptions from the same volcano that enables them to state the material is definitely from the same eruption? I don’t know if this is possible or not.

Jim Clarke
December 4, 2013 10:39 am

NZ Willy’s explanation of two separate eruptions sounds much more plausible. Atmospheric patterns are just not that rigid. I am guessing that none of the authors are forecasting meteorologists…who would know better.

Rob Dawg
December 4, 2013 10:46 am

The very assertion that lake bed deposits arriving from hundreds of miles away over whatever time period it takes for erosion, glacial melting, whatever can be assigned a year is unsupportable. Okay, the volcano erupted 12,140 BCE (BP?) but lake deposits can only be younger than that.

December 4, 2013 11:24 am

The ash of the Katla volcanic eruption thus was deposited at the same time in the Eifel and in Norway.
I doubt the accuracy of the 120 year delay between Germany and Norway.
The ash deposits may be from two rather than a single Katla’s eruption; these are relatively frequent, on average every 50 years during the last 500 years (1999, 1955, 1918, 1860, 1823, 1755-56, 1721, 1660-61, 1625, 1612).

Duster
December 4, 2013 11:32 am

Owen in GA says:
December 4, 2013 at 10:32 am
I wonder if they cross checked the ash assumption with carbon dating of any pollen in the layers immediately above and below the ash layer?

Radio carbon is a bit of a rubber ruler. It can place you in the right ball park, but leave unclear where the seats really are. The Younger Dryas is particularly problematic, and, while there’s considerable debate about this, it seems fairly clear that a large C-14 anomaly (ca. 1,000 years worth) may mark the YD. If so, any C-14 measurement from that period will yield anomalously young dates. Varve counting will usually to be far more reliable, provided the counts are being double checked. Optically stimulated luminescence dating which ought to be somewhat less subject to the environmental vagueries that cause secular variation in geochronological dates is also a possibility. The “gotcha” here is that you and others have been pointing out, these changes are accompanying an abrupt change. Ice sheets are melting, winds are rearranging their delivery routes, etc,

December 4, 2013 11:34 am

In short, all change occurs at the margin, and the margin can move.

TomRude
December 4, 2013 11:36 am

Polar front? Tri cellular model of circulation?
That these authors are still talking of polar front is truly sad. Any observation of atmospheric circulation on satellite imagery over a few days shows that the polar front is a fantasy as cold air masses can penetrate deep toward the equator and even reach it. There is no front stopping them. Thus the meteorological explanation brought up by these author is obsolete and likely wrong. In particular, both cooling and warming can happen at the same time in different palces (even close ones) depending on the trajectories followed by MPHs. It is known that during the onset of the last glaciation, the Svalbard islands were first experiencing warming (likely as a result of being on the path of renewed advection of warm air from colder, higher pressure MPHs that reached farther southward, a warming not dissimilar to Eastern Greenland’s now) until the glaciation progressed to the point of invading these islands.
So the study points toward a shift in circulation yet to be described in detail (likely evolution of the preferred trajectories of MPHs, under what influence?) but it does not unequivocally support their lag time conclusions. A little observation of atmospheric workings from these authors would have gone a long way to offer reality based suggestions in their closing remarks.

tty
December 4, 2013 11:48 am

Answers to a number or questions raised:
The ash is presumably the well-documented and very widespread Vedde ash which occurs all the way from Switzerland and Great Britain to Carelia. This was an exceptionally heavy and widespread ashfall that occurred in mid-Dryas 3. The date for the end of the Dryas would have been determined by counting annual varves after the ashfall. This is a very well established dating technique in northern Europe that allowed the end of the ice-age to be dated at about ten thousand years ago as early as 1912.
So they’re using the Katla eruption as a chronological synchronizer, but the 120yr discrepancy raises the idea that there may have been another eruption 120yr later — maybe even from the same volcano. Prevailing wind patterns could have blown the ash of one eruption in one direction, and of the other eruption in the other direction. Check your assumptions, I say to them.
The Vedde ash is unique in that time-range and no trace of a second similar ashfall has ever been found anywhere. If two huge ashfalls had occurred during Dryas you would expect that both would be present somewhere in the huge area where the Vedde ash occurs. However a negative can never be conclusively proven.
” I wonder if they cross checked the ash assumption with carbon dating of any pollen in the layers immediately above and below the ash layer?”
Not practicable. The abrupt changes in the carbon flux at the end of the ice age means that there is a “C-14 plateau” about a thousand years long at that time, so events during Dryas 3 cannot be reliably separated by radiocarbon dating.
“Perhaps there is a chemical signature in individual eruptions from the same volcano that enables them to state the material is definitely from the same eruption? I don’t know if this is possible or not.”
It is often (not always) possible to identify which volcano or volcanic province an ash layer comes from, and in this case the chemical composition makes it virtually certain that the Vedde ash came from Iceland and very likely that it came from Katla/Eldgja.
“What if one area was still glaciated at the time of the eruption and it then took much longer for the sediment to enter the lake? Sure they cant be accounting for everything!”
No problem. The Dryas End Moraines are very conspicuous in Scandinavia. We know exactly which lakes were glaciated and which were not.
”There must have been a large temperature gradient along that 1,200 Km span leading to some very violent weather.
Very likely. The heaviest hurricane ever to hit Bermuda occurred about 100,000 years age during MIS 5c, an interval when tropical and subtropical areas were about as warm as now, but when there was already considerable glaciation in Siberia and Scandinavia.
The Younger Dryas was certainly a very bad period almost everywhere in the northern hemisphere. The forest trees, humans and most large animals that had colonized Southern Scandinavia either went extinct or emigrated while the cold and dry conditions in the Middle East may have been an determining factor in the development of the first primitive agriculture at this time.
“The very assertion that lake bed deposits arriving from hundreds of miles away over whatever time period it takes for erosion, glacial melting, whatever can be assigned a year is unsupportable. Okay, the volcano erupted 12,140 BCE (BP?) but lake deposits can only be younger than that.”
Its BP, and no, loose volcanic ash doesn’t stay around long before it is overgrown or washed away. Some of the ash will land right in the lake to start with and almost all of it will arrive within a year or two. The lowest annual layer to contain the ash will be either the year of eruption, or the year after if the ashfall was in early winter. Did you visit the Pacific Northwest in the 1980’s? If so how long did it take until the ash from Mount St Helens had disappeared?

tty
December 4, 2013 12:03 pm

The ash deposits may be from two rather than a single Katla’s eruption; these are relatively frequent, on average every 50 years during the last 500 years (1999, 1955, 1918, 1860, 1823, 1755-56, 1721, 1660-61, 1625, 1612).”
Yes but how many of them covered most of northern Europe with ash? None. By the way the 1955 amd 1999 mini-eruptions did not even penetrate the icecap on top of Katla.

Billy Liar
December 4, 2013 12:07 pm

This study is ridiculous. As the ice melted, Northern Germany became ice free because it is relatively low lying and flat. Southern Norway however, still has glaciers, Folgefonna and Hardanger and plenty of mountains (6,000 ft) in the Telemark.
At the same time that Northern Germany became ice free there would have been much larger versions of the current Southern Norway glaciers close by and even the Telemark would probably have been under a glacier. Are we to suppose that Southern Norway, glaciers close by, would have the same weather as Northern Germany, no glaciers and 800 miles further south?

Billy Liar
December 4, 2013 12:11 pm

PS rapid climate change occurs when the permanent ice in your locality finally all melts.

Barry Cullen
December 4, 2013 12:35 pm

NZ Willy says:
December 4, 2013 at 10:17 am
—-
Just as plausible, the ash from the same source could have collected on ice remaining at the Norway site and when it melted 120 yrs later it collected at the bottom of the lake.

Rob Dawg
December 4, 2013 12:44 pm

Barry Cullen says: “Just as plausible, the ash from the same source could have collected on ice remaining at the Norway site and when it melted 120 yrs later it collected at the bottom of the lake.”
No, no, no! Authority “tty” states above that it is all washed away in one to two years. Never mind the US Army Corps of Engineers 33 years after still excavating dozens of feet of ash from navigable rivers near Mt St Helens.

tty
December 4, 2013 2:02 pm

“No, no, no! Authority “tty” states above that it is all washed away in one to two years. Never mind the US Army Corps of Engineers 33 years after still excavating dozens of feet of ash from navigable rivers near Mt St Helens.”
Yes indeed. But neither Norway nor German is “near” Katla. There isn’t a lot of Mt St Helen ash being excavated in Montana or Texas is there (those are at about the right distance) ? Incidentally I know that there was noticeable amounts of Mt St Helen ash in Montana, since I happened to be there about a week after the eruption.
Just as plausible, the ash from the same source could have collected on ice remaining at the Norway site and when it melted 120 yrs later it collected at the bottom of the lake.
Nonsense. Kråkenesvatnet lies on the outer coast, far outside the Dryas 3 end moraines (“raerne” in Norwegian) so there wasn’t any ice in the area at the time, also given the topography, any water from the remaining icecap would have to run uphill across a couple of mountain chains to reach the lake.
This study is ridiculous. As the ice melted, Northern Germany became ice free because it is relatively low lying and flat. Southern Norway however, still has glaciers, Folgefonna and Hardanger and plenty of mountains (6,000 ft) in the Telemark.
At the same time that Northern Germany became ice free there would have been much larger versions of the current Southern Norway glaciers close by and even the Telemark would probably have been under a glacier. Are we to suppose that Southern Norway, glaciers close by, would have the same weather as Northern Germany, no glaciers and 800 miles further south?

Yes, Telemarken was still mostly ice-covered at the time. However Kråkenesvatnet is on the outer coast, at an altitude of about 40 meters, so it is actually a lot lower than Meerfelder Maar at 335 masl (and the difference would have been rather larger at the time because of glacioisostatic effects). However this paper is not about relative climates, but about abrupt climate shifts, such as the end of the Dryas 3 stadial, which is known to have been extremely abrupt everywhere where it has been thoroughly studied.
However it is strange nobody seems to have noticed the real weakness of the paper. As far as I can judge from the press release and the abstract, the event they are referring to is not the end of Dryas 3, but rather the shift from the very cold early part of the stadial to the not quite as cold later part. At least in Scandinavia this was a much less dramatic shift, though it is probably the reason that there are two Dryas end moraines in many areas, and at Kråkenes lake there is about 60 cm of Dryas sediments above this level.

tty
December 4, 2013 2:15 pm

Billy Liar says:
PS rapid climate change occurs when the permanent ice in your locality finally all melts.
Sorry but no. The rapid climate change comes first. By the time the last ice in Scandinavia melted the climate was already a lot warmer than now. In central Sweden pine forest was growing at the top of Mount Åreskutan (1400 meters, way higher than the current treeline) while the valleys below were still ice-covered.

Duster
December 4, 2013 2:45 pm

Steve McIntyre has been discussing the uses and misuses of varve thickness and varve counting here: http://climateaudit.org/2013/12/04/more-on-hvitarvatn-varves/
It is worth reading, especially since it touches upon issues being brought up here. Well worth reading.

Bill Illis
December 4, 2013 4:02 pm

At the Younger Dryas, wasn’t Norway still completely glaciated. I don’t think there were any lakes in Norway at this time that can accumulate varve sediments.

Dr Burns
December 4, 2013 5:51 pm

From what I can see the rapid warming was about 11 deg C in about 200 years. Any better figures ? Makes the [modern] warming look feeble.

Jim G
December 4, 2013 6:39 pm

tty says:
“However it is strange nobody seems to have noticed the real weakness of the paper. As far as I can judge from the press release and the abstract, the event they are referring to is not the end of Dryas 3, but rather the shift from the very cold early part of the stadial to the not quite as cold later part. At least in Scandinavia this was a much less dramatic shift, though it is probably the reason that there are two Dryas end moraines in many areas, and at Kråkenes lake there is about 60 cm of Dryas sediments above this level.”
Would this still not lead you to a very similar conclusion, for whatever reasons, regarding regional climate changes?

Steve Garcia
December 4, 2013 8:57 pm

@NZ Willy December 4, 2013 at 10:17 am
“So they’re using the Katla eruption as a chronological synchronizer, but the 120yr discrepancy raises the idea that there may have been another eruption 120yr later — maybe even from the same volcano. Prevailing wind patterns could have blown the ash of one eruption in one direction, and of the other eruption in the other direction. Check your assumptions, I say to them.”
, UK 10:37 am:
“Perhaps there is a chemical signature in individual eruptions from the same volcano that enables them to state the material is definitely from the same eruption? I don’t know if this is possible or not.”
tty blew this question off, saying, “It is often (not always) possible to identify which volcano or volcanic province an ash layer comes from, and in this case the chemical composition makes it virtually certain that the Vedde ash came from Iceland and very likely that it came from Katla/Eldgja.” As I said, tty blew this off.
Clarke at 10:39 am:
“NZ Willy’s explanation of two separate eruptions sounds much more plausible. ”
See the list of recent dates for eruptions. A volcano that erupts every 95 years or so has ash blow to two different places 120 years apart. This is news?
@NZ Willy at 10:17 am:
“Just as plausible, the ash from the same source could have collected on ice remaining at the Norway site and when it melted 120 yrs later it collected at the bottom of the lake.”
Barry Cullen says:
December 4, 2013 at 12:35 pm
[to NZ Willy] “Just as plausible, the ash from the same source could have collected on ice remaining at the Norway site and when it melted 120 yrs later it collected at the bottom of the lake.”
This lake is on a narrow peninsula, near its end and only 0.25 km from the ocean in both directions. And it ALSO lies on the very top of a rounded hump about 75 feet high. It is a strange location for as many studies as were done of it. Ice would flow away from this location, in all directions – except the very last of the ice, which would settle into the lake. A VERY strange lake location.
@vukcevic at 11:24 am:
“I doubt the accuracy of the 120 year delay between Germany and Norway.
The ash deposits may be from two rather than a single Katla’s eruption; these are relatively frequent, on average every 50 years during the last 500 years (1999, 1955, 1918, 1860, 1823, 1755-56, 1721, 1660-61, 1625, 1612).”
Yes, uniformitarianism would dictate that what happens in the present must also be what happened in the past – unless evidence shows otherwise.
tty did not address the chemistry of different eruptions from the same source, so we can’t rule that out. Not so far.
My take:
I think the researchers have some assumptions that are not valid, and some questions they didn’t ask.
The same eruption affecting two places about 32 degrees apart (based on the volcano’s location), but 120 years separated in time?

[Wiki]
Katla is a large volcano in southern Iceland. It is very active; twenty eruptions have been documented between 930 and 1918, at intervals of 13–95 years. It has not erupted violently for 95 years, although there may have been small eruptions that did not break the ice cover, including ones in 1955 and 1999.
Prehistoric activity
It is thought that Katla is the source of Vedde Ash, more than 6 to 7 cubic kilometers (1.4 to 1.7 cu mi) of tephra dated to 10,600 years BP[1][6][7][8] found at a number of sites including Vedde in Denmark, Norway, Scotland and North Atlantic cores.
Historic activity[edit]
Sixteen eruptions have been recorded for Katla since 930. The last major eruption started on 12 October 1918 and lasted for 24 days.[9] It was likely a VEI-5 level eruption. The 1918 eruption resulted in extending the southern coast by 5 km due to laharic flood deposits. Its present dormancy is among the longest in known history.[10]
Major eruptions occurred in :
2011 – VEI-1?
1918 – VEI-4 or VEI-5; about 0.7 cubic km ejected material
1860 – VEI-4
1823 – VEI-3
1755 – VEI-5; 1.5 cubic km ejected material. Flood discharge 200,000–400,000 m³/s
1721 – VEI-5
1660 – VEI-4
1625 – VEI-5
1612 – VEI-4
1580 – VEI-4
934 – VEI-5 or VEI-6, 5 cubic km of tephra and 18 cubic km of lava

So here is a volcano that for the last 1100 years erupts every century or so. Then they look at two ash deposits 1200 km apart that appear to have happened 120 years apart, and somehow they assume the ash in both places came from ONE eruption, not two eruptions 120 years apart.
They base it on identifying the ash as coming from Katla. Unless there is evidence that Katla has different chemistry with each eruption, there is not reason whatsoever to label these two ash depositions to be from the same eruption.
THEY MAY NOT EVEN BE CONSECUTIVE ERUPTIONS, SINCE 60 YEARS IS NOT AN UNCOMMON INTERVAL.

Steve Garcia
December 4, 2013 9:01 pm

Illis 4:02 pm:
“At the Younger Dryas, wasn’t Norway still completely glaciated. I don’t think there were any lakes in Norway at this time that can accumulate varve sediments.”
Bill, this lake is only 1/4 km from the ocean and near the end of a narrow peninsula. One would think it would be one of the first places to deglaciate in its region.
From a quick reading of the literature, this specific lake was one of the very sources of the name “Younger Dryas.” That is kind of cool, actually.

RACookPE1978
Editor
December 4, 2013 9:13 pm

Steve Garcia says:
December 4, 2013 at 8:57 pm
Somewhat related to your long but excellent answer above, but very relevant to the “theoretical” affect of volcanic eruptions on atmosphere clarity and short-term vs long-term atmospheric temperatures.
Two very large, very specific volcanic eruptions are visible on WUWT’s “solar page” graph of atmospheric clarity vs time since between 1960 and today (late 2013).
http://www.esrl.noaa.gov/gmd/webdata/grad/mloapt/mlo_transmission.gif
One smaller but long-lived impact is visible early on [Mount Agung or Gunung Agung is a mountain in Bali, Indonesia, erupting 1963-1964].
But what eruption caused the very sharp decline is clarity in December 2009 through January 2010? Iceland’s eruption did not occur until April 2010! Surely no one is trying to claim an april volcano caused atmospheric interference in January. 8<)

December 4, 2013 10:23 pm

As I believe Fred Berle said well, “our ignorance is staring us in the face”. There is good documentation of ridiculous rates of climate change in Greenland and the Antarctic peninsula. For some reason the high rates always seem to apply to the warming phase (the natural state of the planet?). The glacial/interglacial oscillations are always characterized by grudging descent and ebullient recovery. I suspect life is the skewing factor.

Steve Garcia
December 4, 2013 10:39 pm

:
“As I believe Fred Berle said well, “our ignorance is staring us in the face”.”
ALWAYS.
Standing at the beginning of a puzzler, we all grope blindly. I liken it to going on a hike, and standing on one crest overlooking a heavily wooded valley, with a destination break in the trees clearly visible across the valley, the path to get to the other valley. Several paths lead down into the woods. Which one to take?
“There is good documentation of ridiculous rates of climate change in Greenland and the Antarctic peninsula. For some reason the high rates always seem to apply to the warming phase (the natural state of the planet?). The glacial/interglacial oscillations are always characterized by grudging descent and ebullient recovery.”
Not so, not at all. I am heavily into the Younger Dryas impact event hypothesis, and I assure you that there was NOTHING slow about the descent into the YD. I’ve seen it shortened to as little as ten years. When gradualists say ten years, since they will NEVER say instantaneous, “ten years” is the same as saying exactly that. See http://www.cosmictusk.com for all the instant YD onset as you can devour. We catastrophists think it was a comet hitting the southern edge of the Laurentide ice sheet in the Great Lakes region. It was perhaps as large as the largest fragment of Shoemaker-Levy 9 comet that hit Jupiter 19 years ago. Maybe larger. There is a lot of work to be done before it is accepted. Or maybe we are wrong. It fits many pieces of evidence, much of it of the forensic type, and it is a simple and elegant solution. But no clear evidence of a crater has been found. We have one good suspect, though. Note that with Alvarez’s dinosaur killer took over ten years to find a crater, and that was serendipity – an oil geologist had done work in that area of Mexico and had all the evidence at hand already.
…In addition, look at the GISP2 Greenland ice cores. There are MANY sudden and BIG shifts in the O18, indicating dozens of sharp drops and as many sharp rises. The YD onset and end (into warm part of the Holocene in which we find ourselves) are just two of them.

tty
December 5, 2013 2:05 am

Bill Illis says:
“At the Younger Dryas, wasn’t Norway still completely glaciated. I don’t think there were any lakes in Norway at this time that can accumulate varve sediments.”
The coastal areas were ice-free and had been so for quite a long time in some cases. Here is a recent summary:
http://meetingorganizer.copernicus.org/EGU2013/EGU2013-13564.pdf
and here is a longer paper (with a map of the Dryas end moraines on p. 14)
http://www.folk.uib.no/ngljm/PDF_files/Mangerud-2003-in-Ehlers.pdf

December 5, 2013 2:22 am

@ Steve Garcia
I tend to agree, except I think the impact was a bit further north at Hudson Bay area (Nastapoka arc). The impact from an ice comet on a thick ice would not leave a crater or any debris but elasticity of the ground ice would result in a shallow indentation; the effects of the impact currently still active.
http://www.vukcevic.talktalk.net/NArc.htm

tty
December 5, 2013 4:51 am

As for the Vedde ash being caused by two different eruptions, it seems extremely unlikely. The ash has now been identified from nearly a hundred sites, including Greenland Ice Cores, deep sea deposits and lake deposits. All these would have continuous deposition and nowhere is there more than a single ash layer during the Dryas interval. The probabilty of two eruptions both having very large, but mutually exclusive, fallout distributions is very low.
However there are other older and younger ash layers that are probably also from the Katla/Eldgja system. The Dimna ash for example..

phlogiston
December 5, 2013 7:10 am

But hang on – AGW orthodoxy is that the Arctic warms FIRST, the “canary in the cage”, and warming moves equatorwards. Now we are told the Arctic warms LAST? WUWT? The Arctic is usually at the top of the list of all the places which are “fastest warming on earth”.

December 5, 2013 7:17 am

Sorry for maybe not on topic, but the other thread was closed.
“ Claim: El Nino events get more extreme as globe warms
…our synthesis of the 14 predefined ENSO reconstructions (Table 1), along with the analysis of 21 single-station proxy records (Table 3), suggests that the observed variance of ENSO over the period 1979–2009 was larger than the variance in any 30 yr window from the preceding 600 yr.“
“Our research suggests in a warming world we are likely to see more extreme El Niño and La Nina events, which over the past decade in Australia have been related to extreme flooding, persistent droughts and dangerous fire seasons,” said lead author Dr Shayne McGregor from UNSW. “Importantly, this study not only tells us how ENSO activity has behaved in the past in relation to global average temperature, it also opens the window for climate models to be able to estimate more accurately how this activity will change in the future.” “By applying these observations and finding which climate models reproduce past changes, we will have a better idea of which climate models are more likely to reproduce the ENSO response to climate change in the future,” said co-author Prof Matt England from the ARC Centre of Excellence for Climate System Science. While the research shows how external warming factors have impacted ENSO cycles, one important question remains. “We still don’t know why. Understanding this relationship will be vital to help us get a clear idea of the future changes to global climate,” said Dr McGregor.

The answers are simple. The ENSO phenomena is locked in general in the amplitude to the heat power from the Sun, still, because the ENSO phenomena is a passive complex impedance from the oscillating Earth axis interference frequency of 1/6.325 y^-1 from the chandler frequency and the Earth frequency. If the amplitude of the heat power from the Sun has an increasing trend over decades, the amplitude of the ENSO index must follow. This can be shown in principle in this graph:
http://www.volker-doormann.org/images/enso_plot2.gif
But to get an idea of the future changes to global climate it needs mainly three more points. The first point is to solve the ENSO oscillators in time and phase. The second point is to separate the ENSO from the heat power from the Sun, and the third point is an unknown, it is the date of time of an effect of the dust of the volcanoes.
The first point can be solved by multiple time intervals of the interference frequency of 1/6.325 y^-1. So after four times of this time interval, after 25.3 years, the main peaks o the ENSO do repeat.
http://www.volker-doormann.org/images/ensoshift1.gif
Because there is a time constant between the ENSO phase and the global temperature of 0.44 years it is easy to show that after a subtraction of a time shifted ENSO function of 0.44 years from the global temperature there remains still a complex global temperature function. But this function can simple be calculated from the solar tide functions generated by planetary couples.
http://www.volker-doormann.org/images/rss_minus_enso34.gif
For the third point it can help to take the well known drop function in global temperature from older volcano effects, when there is a new event of a big volcano outbreak.
Thank you.
V.

Gary Pearse
December 5, 2013 8:27 am

100% confidence that this 120 yr difference in major climate change between Norway and Germany 1000km apart (!) is total bunk. This distance wouldn’t quite get you half way across Ontario! Such a conclusion wouldn’t even have been conceivable in North America. North Americans would almost certainly have been seeking alternative explanations or be laughed out of the hemisphere. Europeans probaby have a much more restricted image of distances considering that they would all fit inside Quebec. I just know someone is going to redo this and come up with one of the sensible explanations offered in the many posts above. It seems that 100% of the commenters here hit on this ridiculous conclusion. 120 yrs diff in 12,450 hrs – less than 1% of the total time elapsed. Oxford and the neutered Potsdamers. We desperately need a “Save the Rhodes Scholars” program if this is where Oxford has deteriorated to.

December 5, 2013 8:57 am

Gary Pearse says: December 5, 2013 at 8:27 am
………………..
An average tortoises could traverse the distance in about 6 months, while a snail would take up to 5 years.

tty
December 5, 2013 11:12 am

mGary Pearse says:
“100% confidence that this 120 yr difference in major climate change between Norway and Germany 1000km apart (!) is total bunk. This distance wouldn’t quite get you half way across Ontario!”
Its actually about 1350 kilometers, which would e. g. get you from Vancouver Island to Fresno, which is a rather more relevant comparison in terms of climate and conditions. Personally I don’t rule out that their hypothesis is correct, since there is evidence that some other Pleistocene climate changes were time transgressive, e. g. it is pretty well established that the last interglacial lasted a couple of thousand years longer in the Mediterranean area than in Northern Europe.
“Europeans probaby have a much more restricted image of distances considering that they would all fit inside Quebec.”
Europe is about 7.5 times larger than Quebec and slightly larger than Canada (or the USA for that matter). IEurope is the second smallest continent after Australia, but since it is much less compact than North America distancea aren’t that different. For example the distance from Portugal to the Urals is about the same as from southern California to New Foundland.

M E Wood
December 5, 2013 12:22 pm

Geologists rely on stratigraphy and like archaeologists rejoice when they get firm dating.
These investigators have good reason to think their results are firmly dated. This technique of varve analysis is an old one and shows successive events very well.
An assumption I am making myself is that winters were longer in more the northerly latitudes and with difference in surface topography could easily, I conjecture, result in later melting of what ever bodies of ice were contiguous to the lakes where the layers were laid down.
The idea that there was one sheet of ice which melted at a steady rate does not seem likely to me. or the idea that ice sheets melted at the same time in different continents. But what would I know?

December 5, 2013 6:09 pm

Vostok shows a pair of warm pulses around 12,240 and 12,120 BP:
http://www.palisad.com/co2/slides/img7.gif

Gary Pearse
December 6, 2013 7:44 am

“Europe is about 7.5 times larger than Quebec and slightly larger than Canada (or the USA for that matter). IEurope is the second smallest continent after Australia, but since it is much less compact than North America distancea aren’t that different. For example the distance from Portugal to the Urals is about the same as from southern California to New Foundland.”
I guess I missed the takeover of Russia (or was it only half of it), although I do recall seeing an article that the Tour de France is going to be extended to Vladivostok next year. Perhaps you also know that the distance from Wawa, Ontario to Moscow is about the same as that from Moscow to Vladivostok. Probably the Younger Dryas was roughly the same across these distances.
Oh and I was 350km out in my estimate. Well then it would be more than halfway across Ontario. Man, the hunger to believe even the most preposterous theory. Did you try to imagine what it was like 200, 500, 1000 km north of the Eifel region? Or did you imagine a 120 year blocking high with a jump in temps across a few kilometres?

phlogiston
December 6, 2013 1:06 pm

@Volcker Doorman
ENSO is not passive.