Paleao Glacial Confusion

  • Thread starter Andre
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  • #1
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Main Question or Discussion Point

In another thread there is a rant going on about the thrustworthiness of the experts about global warming. Let's investigate one of those unrefuted pillars, the ice age, to be more precieze, the termination of the last glaciation and the Younger Dryas.

Then what is the http://encyclopedia.lockergnome.com/s/b/Younger_Dryas [Broken]

The Younger Dryas stadial, named after the alpine / tundra wildflower Dryas octopetala, and also referred to as the Big Freeze, was a brief cold climate period following the Bölling/Allerød interstadial at the end of the Pleistocene, and preceding the Preboreal of the early Holocene.

The Younger Dryas saw a rapid return to glacial conditions in the higher latitudes of the Northern Hemisphere between 12,900 – 11,500 years before present (BP) in sharp contrast to the warming of the preceding interstadial deglaciation. Thermally fractionated nitrogen and argon isotope data from Greenland ice core GISP2 indicates that the summit of Greenland was ~15ºC colder than today during the Younger Dryas. In the UK, coleopteran (fossil beetle) evidence suggests mean annual temperature dropped to approximately -5ºC, and periglacial conditions prevailed in lowland areas, while icefields and glaciers formed in upland areas. Nothing of the size, extent, or rapidity of this period of abrupt climate change has been experienced since.
The discovery of the younger dryas in the GISP ice cores of Greenland was a major contributor to the global warming notion.

I intend to show in a fallacy free way just by combining other peer reviewed information -not even making conclusions - just showing the evidence- that the Younger Dryas was something completely different despite this broad general consensus and that it has nothing to do with global warming - greenhouse effect.
 
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Answers and Replies

  • #2
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Here is the first little crack that happened to trigger a chain reaction:

COMPLEX TIMING AND PATTERNS OF GLACIATION IN THE AMERICAN CORDILLERA DURING TERMINATION 1
CLARK, Douglas H., Geology Dept, Western Washington Univ, 516 High St, Bellingham, WA 98225-9080, dhclark@cc.wwu.edu.

Evidence from alpine glacial deposits in the American Cordillera suggest that glacier fluctuations, and therefore the climatic conditions that caused them, during the late-glacial were spatially and temporally complex.

In the Sierra Nevada, LGM glaciers retreated gradually between 17,000 and ~15,000 14C yr BP (~20,000-18,000 cal yr B.P.) and subsequently stagnated between ~14,000 and 15,000 14C yr B.P. (~16,800-18,000 cal yr BP). By ~13,100 14C yr BP (~15,500 cal yr. BP), ice had largely or entirely disappeared from even the highest cirques. Cirques remained essentially ice-free between 13,100 and 12,200 14C yr BP (15,500-14,200 cal yr. BP), after which glaciers reformed and readvanced a short distance during the Recess Peak event. The Recess Peak glaciers lasted about 1000 yrs, disappearing by ll,200 14C yr BP (~13,100 cal yr. BP). The Sierra Nevada remained largely or entirely free of glacier ice for the next ~9000 cal yr, including during the Younger Dryas (YD) chronozone.

Glacier deposits indicate a mixed record in the North Cascades; alpine deglaciation began by ~17,000 36Cl yr BP, with two late-glacial readvances (~14,000 and 13,000 36Cl yr BP; Swanson and Porter, 1997) in the eastern Cascades, but only one (ending by ~13,200 cal yr BP) in the western Cascades near Mt. Rainier (Heine, 1998). During the YD, glaciers appear to have retreated at Mt. Rainier while simultaneously advancing further north in the Enchantment Lakes Basin. Proposed YD alpine glacier advances to near sea-level in the northernmost Cascades (Kovanen and Easterbrook, 2002) remain controversial, and may instead have been substantially smaller (Burrows, 2000).

In southern Idaho, glaciers retreated to the cirques by 13,000 14C yr BP (~15,400 cal yr BP), but experienced a minor readvance between ~12,800 – 11,000 14C yr BP (~15,100-13,000 cal yr BP); no YD advance is apparent. In the Rockies, small alpine moraines record one or two late-glacial advances, an earlier one that predates YD and a later that is synchronous with it (e.g., Menounos and Reasoner, 1997). These inconsistent results suggest either that current age constraints are in error, or more likely, that the American Cordillera experienced rapid yet localized variations in temperature and moisture delivery, possibly related to an unstable Pacific storm track.
Now what to do with this rebellion? See it as a local anomaly and continue business as usual? or do a little survey about:

The Younger Dryas saw a rapid return to glacial conditions in the higher latitudes of the Northern Hemisphere between 12,900 – 11,500 years before present (BP)
 
  • #3
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I guess it's useless you people want to be mislead,

[deleting physicsforums from "favorites"]

Good bye
 
  • #4
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I hope you don't leave the forums. Different points of view are important. I enjoy reading new lines of thought and studies.
New research is always hard to impress on people. Please don't take it personally, that people don't embrace it.
 
  • #5
matthyaouw
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I agree with hypatia. I enjoy reading your contributions to the forum.
 
  • #6
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Okay, It may be still pointless then but then again, at least I know I have tried and stop the mammoth tanker of the global warming political demagogic campaign.

Again, lets return to the younger dryas. The first person here: http://www.npr.org/templates/story/story.php?storyId=1893089 shows why the ice cores heavily fueled the global warming hype. This is his explanation.

DISCUSSION:
This figure, adapted from the NRC (2002) report Abrupt Climate Change: Inevitable Surprises, comes from data in Alley (2000) and Cuffey and Clow (1997). It shows the clear, abrupt increases in temperature in the Greenland Ice Sheet Project 2 (GISP2) record at the end of the last glacial period and at the end of the Younger Dryas. The cooling as temperatures returned to the glacial conditions of the Younger Dryas takes place over a longer period in a step-wise fashion.
You see: Younger Dryas is a return to glacial conditions. Moreover the methane (CH4) concentration closely follows the "temperature" proxie, that is actually isotopes with a very crude addition of borehole temperatures. So it basically boils down to: methane is greenhouse gas, greenhouse gas is causing climate change (hence global warming). Bingo crusade again greenhouse gas emission.

We shall tear down the myth of the extreme Younger Dryas temperature changes in the next posts, using as tool:

Hughen, K.A., J.T. Overpeck, S.J. Lehman, M. Kashgarian, L.C. Peterson, and R. Alley. 1998. Deglacial 14C calibration, activity and climate from a marine varve record. Nature 391: 65-68.

See the last author? The same. So he could have known.

and remember:
"Non calor, sed umor".
 
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  • #7
matthyaouw
Gold Member
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I'm glad you are back.

I'm slowly sifting through all these sources, though some seem a bit complex to me. One thing in particular stood out as I read it:

Measurements of oxygen isotopes from the GISP2 ice core suggest the ending of the Younger Dryas took place over just 40 - 50 years in three discrete steps, each lasting five years. Other proxy data, such as dust concentration, and snow accumulation, suggest an even more rapid transition, requiring a ~7ºC warming in just a few years
from- http://encyclopedia.lockergnome.com/s/b/Younger_Dryas [Broken]

Now this doesn't seem to add up to me... The impression I'd always got from current climate change theory was that it was a gradual process, and even though any human intervention was drastically speeding this up, the change was still at a mere fraction of the rate suggested above...
I'm not sure I understand.
 
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  • #8
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Exactly, it doesn't add up and if that's the case, there is a fair chance that the interpretation of the evidence is wrong. Then it's time to start thinking out of the box, as discussed in this thread, which means back to the evidence, skip the conclusions (like temperature changes). Investigate ALL available evidence, not only ice cores or ocean floor cores.

That brings us to the carbon dating platform problems first.

more later
 
  • #9
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In this thread we have discussed the problems (and solutions) of Carbon Dating. Especialy this part is essential:

Don't underestimate the accuracy of the mass spectrometer. It registers basically each atom and after the different processes a "BP" date will normally have a 2-rho certainty range of about 2-5%. The problems come however when converting to "Cal BP". Of course there is a repeatedly cross-checked and very accurate converting table but at moments when the atmosphere gets an spike injection of carbon dioxide of different sources with different isotope "signatures" even tables don't help very much. The current injection of fossil fuels is free of 14C and hence the d14C is also dropping independant of the time. This means that objects of an ancienity between now and 1700 AD have about the same "BP" dating. Other of those "Platforms" have been identified around 9000 "BP" is for instance about 9200-11,000 "Cal BP" years, 11,000 BP is something like 13,000 - 14,500 Cal years BP. Here are a few calibration tables.

http://www.rlaha.ox.ac.uk/orau/typical_cal.html
Now recheck my second post and notice that this abstract uses both original carbon BP dates as well as the calibrated dates to calendar years "between 17,000 and ~15,000 14C yr BP (~20,000-18,000 cal yr B.P."

However when you read abstracts it turns out that this is quite uncommon. Several branches in earth science are not modern enough to convert "BP" to "Cal BP". Given the large range of calibration differences compared to the short duration of the Younger Dryas you may talk about completely different timing. That gave me the idea to "audit" several older and modern publications that talked about unusual glacial readvances at the end of the last ice age to see if the calibrated dating of those readvances would coincide with the calibrated dating of the Younger Dryas.

Guess what.
 
  • #10
Monique
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I don't quite follow the following:
Andre said:
You see: Younger Dryas is a return to glacial conditions. Moreover the methane (CH4) concentration closely follows the "temperature" proxie, that is actually isotopes with a very crude addition of borehole temperatures. So it basically boils down to: methane is greenhouse gas, greenhouse gas is causing climate change (hence global warming). Bingo crusade again greenhouse gas emission.
How does it follows from the above arguments that it is a crusade against greenhouse gas emission?
We shall tear down the myth of the extreme Younger Dryas temperature changes in the next posts, using as tool:
So are you suggesting that there were no extreme temperature changes during the Younger Dryas?
 
  • #11
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Thanks for the feedback Monique

How does it follows from the above arguments that it is a crusade against greenhouse gas emission?
Richard Alley will explain:

The ice core showed that at one point, in as little as 10 years, the global climate had drastically changed. Soon after that discovery, climate change became a personal crusade for Alley.
Note: that point being the end of the Younger Dryas with an alleged warming of some 10 degrees far more than can be attributed to pure basic greenhouse gas effect of some 0,7 degrees per doubling of CO2. So at this point the positive feedback factors were invented that would allegedly make the climate very unstable. But that's off topic at the moment.

...there were no extreme temperature changes during the Younger Dryas?
Indeed, I know that this is one of the most basic paradigms of palaeo climate. Nevertheless, it's the intention here of combining the data of all proxies to show - proof- explain the fundamentals of: "non calor sed umor"
 
  • #12
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http://home.wanadoo.nl/bijkerk/c14yd1.GIF [Broken] is our working sheet. Advise to view on 1:1 size. The year scale on the Y axis the upper right site is carbon years BP while the X-axis is Calender years BP. The line of numerous open and closed dots triangles and diamonds are calibration points of several proxies. The annual layers of trees (dendrochronology), lake sediments (varves) etc are both counted and carbon dated and the results are shown. Note that the several proxies are in good agreement. To the bottom I computed the annual precipitiation in the Greenland ice cores (Alley et 2004). Note the boundaries of the Younger Dryas shrink considerably on the y-axis of the carbon dating, roughly from 10,100 to 10,600 14C years BP.

The next idea is to google up all papers with carbon dated glacial readvances in those periods and plot them in on the Y-axis on the BP scale and converting them to the Cal BP scale and see how many fall in the Younger Dryas period.

Questions so far? Do I get help? I found some 25 papers so far.
 
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  • #13
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The first I heard of this was in 1995, and I half to admit I was sceptical. But by 2001 I was convinced that a highly variable climate system was indeed viable.
Things like tree rings and Ice/bog cores don't lie.
 
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  • #14
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Right, and after this, one tends to philosophize about the scientific method like somewhere else in these forums. Anyway, I jotted down the dating results
http://home.wanadoo.nl/bijkerk/YOUNGER%20DRYAS%20GLACIATION1.GIF [Broken]

Again, strongly advise to view it on a 1:1 scale.

The numbers are according the ref list below. Whenever a BP date was given it's on the upper right scale. Sometimes Cal BP dates were given and put in in the middle x-axes. Scroll down to the bottom to see all dates converted to calender years. We see numerous glacial advances outside the Younger Dryas (blue), several with ambigeous datings, crossing borders between the BA - YD and BP (violet) and only an odd glacial readvance within the Younger Drays. I know the method is not perfect but what does that say about this?:

The Younger Dryas saw a rapid return to glacial conditions in the higher latitudes of the Northern Hemisphere between 12,900 – 11,500 years before present (BP) in sharp contrast to the warming of the preceding interstadial deglaciation.
I don't think so. Maximum Palaeo Glacial Confusion.

The refs (I'll elaborate whenever challenged):
1 - Thompson et al 1997
2. - Shanahan et al 2000
3 – Denton et al 1994
4 – Teller et al 2005
5 – Denton et al 1973
6 - Ten Brink et al 1974
7 – Davis et al 1975
8 - Porter 1978
9 - Futyma et al 1981
10 - Sutherland et al 1984
11 - Wright, et al 1989
12 - Benson,et al 1992
13 – Fall et al 1995
14 - Kovanen, 2002a.
15 – Larsen 2001
16 – Thompson 2001
17 – Clark 2001
18 – Bond et al 1997
19 - Benedicta J.B 1973
20 – Lowell et al 1999
21 – Brown 1990
22 – Easterbrook 2002
23 – Bondevik 2002

Not depicted are: Benn et al 1997 Clapperton et al 1997 Chinzei 1987 et al due to ambigious dating: “between 10,000 and 11,500 BP”, as well as Kovanen et al 2002b
“between 10,900 and 10,200 BP”: Kovanen, 2002c.“between 11,000 and 9700 B.P”. Benson et al 1992, and Briner et al 2001 "12.4 and 11.0 ka" Cal(?) 10be26al(?) or 14C(?)
Note the correlation between glacial readvances and precipitation rates in the Greenland Ice core GISPII. In other words "Non calor sed umor".
 
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  • #15
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Now let me try to explain what I tried to explain in this thread:

The current paradigm is that the Younger Dryas was a brief period of intense cold accompagnied by massive glacial readvance. But we are well underway to show that this is a very spurious idea of the Younger Dryas. Instead it was a dry event with no reason to assume that the period was colder than either the previous Bolling Allerod "interstadial" or the following Pre Boreal period.

We have shown that the vast majority of (global) glacier readvance actually occured outside the Younger Dryas with peaks just prior and after this event.

The reason of the widespread misconception is probably related to the problems with carbon dating. Early pollen records showed an explosion of the tundra flower Dryas octopetala pollen that could be dated between 10,000 and 11,000 BP (carbon years), moreover the total number of pollen was highly decreased in this period. Next, there were many glacier readvances datable "between" 10,000 and 11,000 carbon years "within the Younger Dryas" (but actually AT both 10,000 BP and 11,000 BP - not in between and consequently outside the Younger Dryas). So from this, the hypothesis of the cold Younger Dryas with glacier readvances was formulated and later that hypothesis was "confirmed" by the stable isotope (d18O, dD) behavior of the Greenland ice cores GRIP and GISP2. On the other hand, the cold "Younger Dryas" confirmed that the isotope behavior was temperature related. So due to this beautiful circular reasoning - begging the question, the cold Younger Dryas is now one of the most deeply rooted errors in paleao climate.

The problems related to carbon dating are the highly variable delta 14C around the end of the Pleistocene. This caused a distinct "carbon dating platform" or a relatively small change in carbon dating was in reality a large change in actual calendar dating. So the only thing what we did is calibrating all known glacier readvance carbon dates to real calendar dates. The result is that almost all readvances occured outside the Younger Dryas in the alleged "warm" Bolling Allerod and Holocene. Also the massive glacial retreats are dated around 17-13,000 carbon years or between 21 and 15,000 calendar years ago, well before the alleged warm Bolling Allerod. The interruption of the glacial retreat and some glacier readvance happened shortly after 13000 carbon years or 15,000 real years ago or at the onset of the alleged warm Bolling Allerod. So if the slight warming of nowadays (~0,6C) causes large scale glacial retreat then how can the distinct warming of the Bolling Allerod (5-7C) cause a glacial readvance?

It can be concluded that the Bolling-Allerod event as well as the onset of the Holocene (Pre Boreal) were not warm at all. It was very wet instead and furthermore that the Younger Dryas was a dry event, not necesarely colder, hence: non calor sed umor.

Another consequence is that the stable isotope behavior in the ice cores are not primarily temperature related but moisture related. But this error is the base of the global warming idea, assuming an unstable global climate with large positive feedback factors, causing a strongly increased greenhouse gas effect after a small increase of CO2 in the atmosphere. This was ultimately the reason for some people to crusade against global warming. Too bad. So, sloppy science without correcting for the well known carbon dating error is going to cost the world dearly by aiming the corrective measures to the wrong cause.
 
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  • #16
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So that all basically implies that the current understanding of the ice age can be trashed and this is normal, not exception:

Björk S, et al. (2002) Anomalously mild Younger Dryas summer conditions in southern Greenland, Geology; May; v. 30; no. 5; p. 427–430;

ABSTRACT
The first late-glacial lake sediments found in Greenland were analyzed with respect to
a variety of environmental variables. The analyzed sequence covers the time span between 14 400 and 10 500 calendar yr B.P., and the data imply that the conditions in southernmost Greenland during the Younger Dryas stadial, 12 800–11 550 calendar yr B.P., were characterized by an arid climate with cold winters and mild summers, preceded by humid conditions with cooler summers.
Emphasis mine

Remember that thats exactly the same area with the claim:

Grachev AM, Severinghaus JP, (2005) A revised +10±4 °C magnitude of the abrupt change in Greenland temperature at the Younger Dryas termination using published GISP2 gas isotope data and air thermal diffusion constants. Quaternary Science Reviews Volume 24, Issues 5-6 , March 2005, Pages 513-519

Abstract
We revisit the portion of (Nature 391 (1998) 141) devoted to the abrupt temperature increase reconstruction at the Younger Dryas/Preboreal transition. The original estimate of +5 to +10 °C abrupt warming is revised to +10±4 °C. The gas isotope data from the original work were employed, combined with recently measured precise air thermal diffusion constants (Geochim. Cosmochim. Acta 67 (2003a) 345; J. Phys. Chem. 23A (2003b) 4636). The new constants allow a robust interpretation of the gas isotope signal in terms of temperature change.
Good for the trashcan from the onset. That's what happens when you specialize and fixate on one item only.
 
  • #17
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according to your rapid polar wander theory, ice ages did not happen. hence net volume of ice on earth does not vary significantly through time.however how would you then explain the large variations in sea level that were experianced throughout the holoscene epoch?
 
  • #18
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Hi Sage,

Consider this, there is an ice age hypothesis with waxing and waning ice sheets. This requires an sea level yoyo. So we go to Barbados, (nice place) and investigate. And what do you know, the sealevel behaves nicely according to that yoyo. So we try other places, and then some nasty things happen. We sea all around the South Chinese sea holocene sea level lowering hapening. The same around St-America and regarding Beijing, that was also sea bottom less than 80,000 years ago (Wuchang Wei 2002). Fortunately, Australia is behaving nicely again. So if you read publications about the sea level behavior and ice ages, plot the areas that are refered to. You will see that it concentrates in two areas, the Carribean and Australia / Indonesia

So we appeared to have a problem for a moment but we have two places now that sustain the sea level yoyo. So we write that triumphantely in the IPCC reports, a sea level rise of 126 meters murmering something about some local regions that abbarate due to local tectonic conditions. However 5 cm/year in the beginning of the Holocene for the South Chinese sea is way over the estimated maximum (15mm) tectonic uplift rate.

So, you see that the sea level change idea is much more complicated. And of course, the Canadian Laurentide and European Weicheselian ice sheets did disappear after the Last Glacial Maximum and would have been good for some 50 meters of sea level rise. For that 126 meters we would have needed a considerable Siberian ice sheet, but any ice in Siberia melted 60,000 years ago already, long before the Last Glacial Maximum.

All in all, the erratic sea level changes seem to have more to do with tectonics and guess what caused all those severe tectonic movements concentrated around the Pleistocene-Holocene boundary?
 

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