Since I discussed the presumed Eemian mosses being exposed on Baffin Island discovered by Miller et al (2013) and the clueless response from WUWT, I’ve seen that others are discussing this paper, including Steve McIntyre, Judith Curry, and Jim Bouldin.
Curry’s contribution can be summed up as
The reasoning behind the Miller et al. conclusions is rather complex, with a number of assumptions, I’m not sure what to make of their arguments.
Both Bouldin and McIntyre comment that at some of the icecaps’ margins, the moss appearing from under the melting ice is mid-late Holocene, at others it is >~40,000 years old, presumably Eemian. For example, from McIntyre,
A question: How does one reconcile the supposed in situ continuity of the little “ice cap” in the vicinity of sample M10-B231v (1395 m) since 44000 BP with recession in the vicinity of nearby higher M10-B226v (1438 m)?
Let’s get the virtual crayons out to try to explain what is happening.
Eemian. Live mosses (green) on the mountain top.
The Eemian (strictly some time prior to ~40,000 years ago) was warmer than the Holocene because the Earth’s orbit was different leading to higher solar insolation during summer. Mosses and lichens grew across the mountain top.
Last Glacial Maximum. Dead mosses (brown) under Pleistocene Ice (thick blue line)
Following the Eemian, the Earth’s orbit changes, summer insolation decreases, the climate cooled and an icecap developed on the mountain top, preserving the mosses beneath it. Because of the shape of the mountain top, the maximum thickness of ice that can accumulate is ~70m (any more and the ice flows over the edge of the summit plateau).
Early Holocene. Live moss (green) and dead Eemian moss (brown) under Pleistocene ice.
During the Early Holocene, much of the icecap melts under the high insolation at the time (but not as high as in the Eemian). Eemian moss remains preserved under the icecap, Early Holocene mosses grow around it.
Late Holocene. Dead Eemian (brown) and Holocene (orange) moss under Pleistocene (thick line) or Holocene (thin line) ice.
The climate cools in the late Holocene as summer insolation deceases in the Arctic. The icecap grows again. Eemian mosses remain preserved under the centre of the icecap under ice from the last glaciation. Holocene mosses are preserved nearer the periphery under late Holocene ice. The Holocene mosses are not those that grew at the thermal maximum, but the last ones to grow before the icecap overwhelmed them.
20th Century. Live moss (green) with some dead moss of Eemian (brown) or Holocene (orange) age being exposed by melting ice.
The 5,000 year long cooling trend is reversed in the 20th Century under the influence of anthropogenic forcings. At some parts of the ice margin, Eemian mosses are exposed, at others mid-late Holocene mosses are exposed. This is what concerns Bouldin and McIntyre.
First, it should be noted that the inner-most mid Holocene moss will be very close, perhaps less than a metre, away from the outermost, Eemian moss. So unless ice accumulation and melting occurred in a perfectly symmetrical pattern, it is expected that as the first Eemian mosses are being exposed from under one margin of the icecap, mid-Holocene or later mosses are being exposed from under another. In reality, ice accumulation and melting will be far from symmetrical on these icecaps: both will depend on the slope, aspect and situation. Snow and ice accumulation will be fastest on the lee side of the icecaps, where there is some slight protection from the prevailing wind; melting will be fastest on south and south-west slopes that receive the most solar insolation. So some areas will have accumulated much ice during the late Holocene, other areas rather little. It is implausible that 20th Century melt would perfectly compensate for this, melting the high accumulation areas faster so that Eemian moss is exposed simultaneously in all areas. Of course, one could do a couple of PhD’s worth of research to explain the fine details of the ice accumulation and melt on Baffin Island’s ice caps so we perfectly understand why some ice margins are exposing Eemian mosses, other late Holocene mosses. Another few years delay wouldn’t do any harm would it?
It is also worth noting that the icecaps are far from equilibrium with climate – they are, or at least were in the period 2000-2005, melting 0.5m/year. Such rapid melting implies that the icecap will shrink further should the climate remain warm, potentially melting all the ice.
One potential confounding factor, not covered by any discussion I have seen about this paper, is the role of black carbon changing the albedo and hence melt rate of the ice. However McConnell et al (2007) show from ice core records, that black carbon deposition on Greenland peaked between 1900 and 1950, before declining substantially, so this is probably a relatively minor issue.
@richardjtelford
Musings on Quantitative Palaeoecology 
Thank you for your explanation. Can one tell one type of ice from the other? That is, is there an independent check of how old the ice looks in some fashion?
Some ice caps on Baffin Island are known to contain Pleistocene ice (eg Hooke (1976) http://www.igsoc.org/journal.old/17/75/igs_journal_vol17_issue075_pg49-59.pdf)
The isotopic composition of the ice is the obvious thing to check. The Pleistocene ice should have a different composition to Holocene ice as the climate was colder (see for example any Greenland ice core). However, these melting ice caps will be suffused with melt water that refreezes in winter, this may mask the signal.
Thanks for this Richard, it’s very useful in helping visualize the process, at least for me, so this is blogging time well spent.
In thinking this whole thing through a little more, I think at this point my questions boil down to the following: For the Holocene-aged moss being uncovered at the 135 sites, the authors conclude that temperatures now are warmer than they were when those mosses were killed by the descending snow line (all < 5kya, mean of ~ 1200kya). I initially stated (in a comment on your other piece) that this must indicate that air T at that time, at those sites, must thus have been about = to the present. I now realize that was mistaken, but I nevertheless still wonder how well we really understand what the air T's were at the time. Isn't one plausible explanation that it could have been quite warm (say, about = to the present, or somewhat less) at the time, followed by a rather sudden summer cooling that dropped the snowline quickly, killing the moss, with the snowline never again rising since that point?
The other question I would have is that even though presently the summer air T's account for 90% of snowine fluctuation (according to the authors)–who is to say that winter precipitation (i.e. snow) was not a bigger factor in times past. I'm not arguing that it was–I have no idea– but I don't know how they can assume that it wasn't either.
The bottom line is I just don't understand how, for the Holocene aged samples, they can be so confident that summer air temperatures, at a time preceding the killing of the moss, was necessarily lower than it has been for the last several decades.
If it had been as warm as modern for more than a century during the Holocene, the ice entombing the Eemian moss that is now being exposed would have melted. Short hot periods are compatible with the continued preservation of Eemian moss.
The authors discount changes in precipitation by noting that the accumulation rate on Greenland (one of the few places with reliable estimates) does not vary significantly during the Holocene. This is not fully convincing as Baffin Island climate would be more affected by the early Holocene decay of the remnant Laurentide ice sheet than Greenland. However, some fairly large changes in accumulation would be required as the temperature sensitivity of glaciers is normally high (see for example figure 3 here – wanted a cold-based glacier but cannot find evidence at this time of night.)
So let me get this straight…ice from the previous GM is finally melting, and we are supposed to be alarmed?
The science (empirical evidence) presented in this whole episode is quite fascinating. The framing however, reduces it to ridicule.
The current stage of recession implies nothing about the relative magnitiude of current conditions; only that they are sufficient to melt new accumulations and some underlying ice.
A look at the CET will show the Thames closer to ice fairs than to hippos.
Let me guess – you are not a glaciologist.
I would recommend starting with something on glacial mass balance and how glaciers respond to climate.
Well I am no expert but I am familiar with glacial mechanics. It is an oversimplification to conclude that temperature alone dictates “Glacial Mass Balance.”
McIntire cites a glaciologist who studied the specific area in question as stating that precipitation is the principle driver of glaciation in this area. So one must include variability in precipitation as part of “climate”- it is not temperature alone. And claiming it proves it is currently as warm as the Eemian is just preposterous.
I am also curious as to how early Holocene conditions melted the great Laurentide while not the less extensive Baffin island ice, which the evidence does seem to imply.
BTW I do enjoy your blog, I am a long time lurker.
Richard I believe you also missed J Curry’s main point, that is the author’s extrapolating from one point to the entire Arctic and then the entire globe, is not warranted.
Here is one unpaywalled paper supporting both earlier warmer temps in Baffin, and the importance of precipitation in local glacial conditions:
http://onlinelibrary.wiley.com/doi/10.1002/jqs.1286/abstract
Abstract
With accelerated melting of alpine glaciers, understanding the future state of the cryosphere is critical. Because the observational record of glacier response to climate change is short, palaeo-records of glacier change are needed. Using proglacial lake sediments, which contain continuous and datable records of past glacier activity, we investigate Holocene glacier fluctuations on northeastern Baffin Island….glaciers may have persisted in proglacial lake catchments ….The finding that glaciers likely persisted through the Holocene is surprising, given that regional proxy records reveal summer temperatures several degrees warmer than today, and may be due to shorter ablation seasons and greater accumulation-season precipitation.
The paper does not extrapolate to the whole Arctic. From the conclusions:
Even the press release is clear on this:
I don’t think that Curry is accusing the authors of claiming that the results can be extrapolated.
Baffin Island was certainly warmer during the early Holocene. Pollen data suggests ~1-2°C. The paper you cite claims up to 5°C based in part on chironomid data. I find this unlikely, as 1) few places were that much warmer in the early Holocene, 2) Baffin Island was affected by the remnant Laurentide Ice Sheet so is not the place likely to have had the most warming, and 3) chironomids are not the most reliable temperature proxy (see Velle et al 2010). If, as is likely, the temperature was not as extreme as Thomas et al suggest, then there is little need to invoke precipitation changes to explain the survival of ice on Baffin Island.
phodges said
Your reasoning here seems to be one of argument by authority.
Which study from which glaciologist does McIntire mention exactly, and what exactly does that glaciologist say ?
To play devil’s advocate : between 15 kya and 8 kya, most of the Laurentide ice sheet ice sheet melted away, causing sea levels to rise by 100 meters. Is McIntire or this glaciologist claiming that this was also due to precipitation changes as “the principle driver of glaciation in this area” ? Or may temperature increase due to increased solar irradiance have something to do with it ?
The abstract says Arctic air temperatures have increased and recent Arctic warming in the first two sentences. The authors conclude an anthropogenic forcing for the cause, I would call that a global extrapolation.
While your objections to Thomas, E. K., Szymanski, J. and Briner, J. P. 2010 raise questions about their specific conclusions, there are lots more papers out there with similar claims. I linked only one.
The mass of evidence and publications demonstrate that the Arctic in general was warmer even in the 30’s than now, never mind the Medieval and Holocene Optimums. Just one source:
http://m.earthobservatory.nasa.gov/Features/ArcticIce/arctic_ice3.php
And Rob, my argument by authority cites ultimately, another paper by Miller himself:
Click to access andrews1972.pdf
I just think in this moss paper the authors have made overly broad and specious conclusions. I could list a litany of counter arguments. I mean I literally laughed when I saw the headlines.
Arctic air temperatures have increased recently. This is a statement of fact not a conclusion drawn from their work. In the absence of any other forcing factor that could explain the recession of the icecaps, it is not unreasonable to blame greenhouse gases.
That the early Holocene was warmer than the late Holocene at high latitudes is not the issue. The thermal Holocene thermal maximum is supported by hundreds of papers, some of which I have co-authored, and the cause, orbital forcing is well known. What is at issue is how precipitation has changed over Baffin Island over the Holocene. Andrews et al needs to be treated with care because of its age. The data are fine, but the interpretation needs to be read in view of the state of the science at the time. 1972 was at a time when Milankovitch forcing was much less well understood (and not fully accepted) and before records of the glacial-interglacial CO2 concentration were available.
I look forward to reading your litany of counter arguments.
I look forward to reading your litany of counter arguments.
LOL, thanks for the invitation Richard. I’ll try to stick to what we have so far, especially considering most of our differences are likely A Priori. I have repeated my main objection…that the authors draw overly broad conclusions from the evidence. That said, I am behind a computer now rather than my phone I apologise ahead of time 😉
Arctic air temperatures have increased recently.
A far more cautious statement than “as warm as the Eemian” The authors refer to a century scale, obscuring that the bulk of the warming occurred from 1900-1930, and it was warmer in the 30’s than the more recent peak. This also seems to refute an anthropogenic attribution, as anthropogenic forcing is generally accepted as starting only in the late 70’s
In the absence of any other forcing factor that could explain the recession of the icecaps, it is not unreasonable to blame greenhouse gases.
Natural Variability. Underrated and apparently little understood. What caused the swings between previous optimums, and the LIA? Various GISP cores show very wide swings in temperature. I would also suggest that blaming greenhouse gas is assuming the consequent.
What is at issue is how precipitation has changed over Baffin Island over the Holocene.
Well the paper I referred to in my previous post also emphasized precipitation as a primary factor in local ice equilibrium…and there are many more that could be cited.
Giff Miller has graciously responded over at Climate Etc, here was my take:
We never claim that our data demonstrates Arctic-wide unprecedented warming…. Of the primary factors determining the planetary energy balance, GHG remain by far the most likely term to explain such unusual summer warmth.
You are indeed generalizing from increased summer temperatures in the study zone to a global phenomena. Or is anthropogenic co2 raising the temperature only in the “Eastern Canadian Arctic?”
A priori objections are boring. You could recite these without reading the paper. A posteriori objections are more interesting.
Nobody who understood this paper could claim that it showed that it is now “as warm as the Eemian”.
Anthropogenic forcing began in the 1970s? Generally accepted by who? Were CO2 emissions prior to 1970 radiatively transparent? Did the early 20th century peak in carbon black do nothing?
phodges said :
while in fact the paper internet entity “phodges” apparently refers to (Thomas et al 2009) states :
When one understands that early Holocene Arctic winters were longer (and milder) and summers (and warmer) were shorter, Thomas et al’s remarks make perfect sense.
Which tells more than enough about the hyperbolic deductions internet entity ‘phodges’ apparently is capable of.
Nuf said.
Wow. Just wow.
Nobody who understood this paper could claim that it showed that it is now “as warm as the Eemian”.
…with average summer temperatures of the last ~100 years now higher than during any century in more than 44,000 years — from the Abstract
“Unprecedented recent warmth in Arctic Canada” —-the Title.
Unprecedented since when???
Why do you insult me Mr. Deker? By your own statements, you agree with me-
To summarize my point, the claim that 10 samples of mosses and lichens from one area on Baffin Island are enough to claim that temperatures in the Eastern Canadian Arctic are higher now than they were for 120,000 years
Which EXACTLY what I have been saying.
I also fail to understand how “The finding that glaciers likely persisted through the Holocene is surprising, … and may be due to shorter ablation seasons and greater accumulation-season precipitation” refutes my contention that Miller et al cherry picked their assumption excluding precipitation as an equilibrium factor…granting I should have said “a main driver” rather than “the main driver”.
And Rob, the paper from which you continue to accuse me of arguing from authority is Andrews et al 1972, co-authored by Miller. Not Thomas et al 2009. Again, why the insulting attitude?
There a many many papers covering the issue of precipitation as a factor in Western Greenland and the Baffin/Ellesmere area glacial stability. I.E.:
Box finds decadal variations ranging from -25% to +16% since 1840, in Greenland Ice Sheet Mass Balance Reconstruction. Part I: Net Snow Accumulation (1600–2009). J. Climate, 26, 3919–3934. http://dx.doi.org/10.1175/JCLI-D-12-00373.1
Drinkwater finds recent variations in accumulation rates and also in the regional circulation patterns that may affect Baffin Bay-
Drinkwater, M.R et al. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. D24, PAGES 33,935–33,950, DECEMBER 27, 2001
“Results of applying the simple empirical relation yield accumulation differences that indicate changes in the spatial patterns of Greenland snow accumulation and melting during the intervals 1978–1996 and 1997–2000. Observed changes are interpreted as a recent large-scale reversal in the net accumulation trends along large parts of the northwestern flank of Greenland that indicate more frequent cyclonic activity in Baffin Bay and in turn more frequent negative phases of the NAO.”
Even the Koerner paper cited in Miller 2013 contradicts much of what Miller has cherry-picked from it. While I think this is in fact fine – evidence is evidence – it just needs to be acknowledged that this is what he has done. Even in his response over at J Curry’s blog he did not address this issue.
And while Millers citations of Koerner may be relevant to the study cite, that is a far cry from supporting “Unprecedented recent warmth in Arctic Canada” and “warmest century in 44,000 years”.
Oh dear.
The Eemian was 130-115 thousand years ago.
That Baffin Island is now warmer than it has been, on a century scale, in 44,000 years does is not an argument that it is now as warm as the Eemian. That Baffin Island is now warmer than any time since the Eemian is not an argument that it is now as warm as the Eemian.
Peak Eemian temperatures in high latitudes were several degrees warmer than Holocene temperatures. The icecaps on Baffin Island were likely all melted away. It is not that warm. Not yet anyway.
That Baffin Island is now warmer than any time since the Eemian is not an argument that it is now as warm as the Eemian.
Aha. You are making a claim distinct, or more precise anyway, from the authors. As you noted yourself, can there by any wonder at the hoopla when such ambigous, almost meaningless claims are made:
“with average summer temperatures of the last ~100 years now higher than during any century in more than 44,000 years” — from the Abstract
“Unprecedented recent warmth in Arctic Canada”- the title
Warmer than the Holocene implies as warm as the Eemian…as you note, warmer than the middle of a glacial is completely moot.
Had the authors rather more accurately said “Recent Temperatures on Eastern Baffin Island Equivalent to or Higher than Holocene Optimum” they would have robbed us of all this entertaining blogging.
Regardless, the paper is still a tangled web of contentious assumptions used to pyramid tenuous conclusions. Much of which has been noted and addressed here, Climateaudit, and Climateetc.
Nonsense.
phodges said
I’m not insulting you phodges. I’m pointing out that your statement that
is not sustained by evidence. Not even by the two papers that you quote.
And by the way, the name is Dekker. Not Deker.
And what is your name ?
Hi Richard,
I arrived here via a reference by Neven at the ASI blog.
Thank you for your comprehensive explanation of what may have been going on with these ice caps during the early Holocene, and how mosses may be distributed underneath the remaining ice.
My question is about the fraction of Eemian versus (late) Holocene samples that now appears from underneath these ice caps.
If we are indeed now close to melting into the pre-Holocene ice cap cover, then, assuming accumulation and melting probably occurred in an a-symmetrical way, then should we statistically speaking not expect to see about 50% Eemian and about 50% Holocene samples appear ?
Instead, it seems that 93 % of Miller’s 145 samples dated to less than 5000 years old, and only 10 samples were Eemian.
Isn’t that suggesting that still the vast majority of soil appearing from underneath the receding ice caps on Baffin Island were ice free during the mid Holocene ?
I understand your point about climate currently not being in equilibrium, but it seems to me that unless we will start finding increasingly larger fractions of carbon-dead samples in future exploration, the conclusion that it’s now warmer on Baffin Island than any time during the Holocene may be a bit pre-mature ?
The proportion of Holocene and Eemian moss will change with time. Initially only Holocene moss will be exposed. Then mostly Holocene moss (the current situation), then, if the icecap is still not in equilibrium, more of the Holocene ice will be lost and the moss will be 50% Eemian, then ~100% Eemian. Finally, if it continues to warm so that equilibrium line altitude is higher than the mountain top, the icecaps will disappear.
The icecaps on Baffin Island (and elsewhere throughout the Northern Hemisphere) grew substantially in the late Holocene as a response to declining summer insolation (giving both cooler temperatures and less short wave radiation) as the Earth’s orbit changed. Miller et al report that the regional snowline fell by 650m in the late Holocene, so it is expected that most of the ground appearing from under the ice was exposed during the mid Holocene.
I’ve not seen anybody suggest a credible alternative explanation for the Eemian mosses melting out, so the preliminary conclusion has to be that it is now warmer. Remember there is now less 5% less shortwave radiation than in the mid-Holocene at this latitude because of orbital changes, so it is now harder to melt the ice than it was. This makes the melt all the more exceptional.
Thanks for your reply, Richard.
The scenario of melt progression you present may very well be correct, but the questions that remain seem to be twofold :
– Where are we now, when considering the evidence from Miller et al 2013, and
– How fast will be progress to the future states that you present.
Regarding the first question, please note that the data that Miller et al 2013 presents shows that some 60 % of the samples that are currently emerging from beneath the Baffin Island ice caps is younger than 1500 years.
Thus, in my view, they are making a strong case that current climate is unprecedented over the past 1500 years, which incidentally, matches with the findings about Arctic sea ice from Kinnard et al 2011
But it seems to me that with a-symmetric melting at the edges of these ice caps, the 10 samples that dated carbon dead are not statistically significant enough to validate a conclusion that at this point the temperatures around Baffin Island (let alone the entire Arctic) are higher than during the entire Holocene.
Regarding the second question, with GHG emissions still increasing, I share your concern about the scenario of continued melting you present, but I think the timeframe under which that would happen remains to be debated and should be sustained by evidence.
For example, even theoretically speaking, the 5 % increased solar irradiance during the early Holocene you mention is some 67 W/m^2 solar irradiance difference. Expressed in radiative forcing that is still some 17 W/m^2. With a doubling in CO2 causing increase in radiative forcing of only 3.7 W/m^2, could you please give us your perspective on the theoretical time frame over which you think the Baffin Island ice caps will seriously start melting into pre-Holocene ice (if there was much of that ice to begin with) ?
If the mean melt rate of 0.5m/yr continues we won’t have long to wait before the thin (<70m) icecaps are gone.
The Kinnard et al reconstruction is only 1450 years long, so cannot evidence the early Holocene conditions.
It is a mistake to consider the moss to come from a single population. There are multiple populations, some Holocene, some pre-Holocene. A single rooted pre-Holocene moss (abet with multiple dates to check for instrumental failure) would be enough to prove that Pleistocene ice is melting. Ice that didn't melt through out the early Holocene.
Richard said :
Kinnard et al had quite a bit of data dating more than 1500 years ago, but they decided that this data was not statistically significant enough to be included.
After all, a few proxies from one place do not validate any conclusions for a larger temporal or spacial area.
and related :
You are right. For these particular 10 local spots where these pre-Holocene samples were found.
But these few samples do not give you the statistical right to validate a conclusion about temperatures over the wider Baffin Island area (let alone the East Canadian Arctic as Miller et al 2013 concludes), nor over the wider temporal “pre-Holocene” time period.
Sorry Richard. Forgot to insert a / in that closing HTML tag.
To summarize my point, the claim that 10 samples of mosses and lichens from one area on Baffin Island are enough to claim that temperatures in the Eastern Canadian Arctic are higher now than they were for 120,000 years, while 93 % of the samples are younger than 5000 years, are statistically speaking even worse than the (bogus) claims that global warming stopped in 1998.
The distribution of ages is exactly what is expected when the remnant Pleistocene ice begins to melt. Repeat the analysis after ten more years and the ratio will probably change in favour of the Eemian mosses.
If you are interested in the mean, then focusing on the extreme values is an error. Nobody is interested in the mean age of ice melting: the ice caps are not in equilibrium with climate.
Richard, your article does not respond to my question, which was : “How does one reconcile the supposed in situ continuity of the little “ice cap” in the vicinity of sample M10-B231v (1395 m) since 44000 BP with recession in the vicinity of nearby higher M10-B226v (1438 m)?”
It’s a different question than that asked by others and your response seems almost intentionally obtuse. About 1 km from B231v is a similar icecap at higher elevation where receding ice has merely exposed Holocene moss. The seemingly inconsistent information from the two sites was not reconciled in the article or in your non-response.
From Miller et al, the lapse rate is 4.9 +/- 0.4 °C/km. So a 43 m difference in altitude should give a 0.2°C difference in temperature. Is it really so hard to consider that differences in slope, aspect and situation could not change the accumulate and ablation patterns enough to overcome this small difference in temperature?
Then the converse also applies, that it is the lower site is the exception. Not the more numerous higher sites!
Hi Steve,
There is an internet entity here by the name of ‘phodges’, who claims that :
Never mind the mis-quote of your name, he did the same with mine.
But could you please shed some light on which study from which glaciologist you mentioned exactly, and what exactly you said that this glaciologist said ?
And feel free to comment if you think that ‘phodges’ is spreading myths under your name.
Rob,
Steve McIntyre writes as the last paragraph of his post (added as an update to the original post)
How relevant is this comment from 1972 to this discussion is one question. Equally significant is the observation that the present authors are surely well aware of their early work, and that they comment on the potential role of durable changes in precipitation in their new paper.
Pekka said
Thanks for the quote to what Steve put on his blog.
I agree that the relevance of a single comment in a 41 year old paper may require some discussion before it is presented.
Did McIntyre do that ? Or did you only put out the comment itself, mentioning only the authors and no discussion, nor context on how the climate at Baffin Island has changed over the past 40 years ?
P is for Peter. I apologize for misspelling your and Steve’s names, my excuse is I am hastily throwing these together between other tasks and fail to proofread and double check everything. The earlier posts were typed on my phone.
Yes, I was wrong to write “the principle” rather than “a principle”. One paper I cited says precipitation is the principle driver, one paper implies precipitation and temperature are both important. If you look through the literature, you will find many more disputing that temperature alone is the main driver. Why is that so hard to understand??
My opinion is that the Miller et al 2013 made a choice that temperature is the principle driver, which is a contestable assumption. Especially considering the other information in the Koerner paper he cites as supporting his assumption. After using this assumption to infer higher than insolation forced temperatures, he uses this local result to then argue for global CAGW forcing. This requires another whole host of arbitrary assumptions.
Here is one more paper regarding the region (Western Greenland), which more soberly addresses these issues:
1)Early Holocene temperatures only 2-3c warmer than present 2) Climate variability exceeds insolation forcing
Click to access AxfordY_HoloceneTemperatureHistory_2013.pdf
From the abstract:
Gradual, insolation-driven millennial-scale temperature trends in the study area were punctuated by several abrupt climate changes, including a major transient event recorded in all five lakes between 4.3 and 3.2 ka, which overlaps in timing with abrupt climate changes previously documented around the North
Atlantic region and farther afield at w4.2 ka.
Discussion:
The onset of this transient event in West Greenland overlaps with the timing of abrupt climate shifts documented at many sites far from West Greenland w4.2 ka, including evidence for drought in central North America (Booth et al., 2005), glacier advance in western North America (Menounos et al., 2008), increased wetness and cooler conditions in northern Britain (Langdon et al., 2004; Langdon and Barber, 2005), and hydrologic changes implicated in cultural upheavals in the Middle East and south Asia (deMenocal, 2001; Staubwasser et al., 2003). More locally, Moros et al. (2006) record substantial environmental changes in Disko Bugt sediments at w4 ka based on diatoms and sediment physical proxies.
Masson-Delmotte et al. (2005) highlight an abrupt drop in GRIP deuterium excess at 4.5 ka, and suggest that this change in isotopes of precipitation over central Greenland may have recorded a shift in regional hydroclimate.
The conclusion:
The occurrence of abrupt climate shifts in West Greenland during the Holocene reinforces the notion that Holocene climate, which at high northern latitudes was primarily driven by gradual changes in summer insolation, exhibited non-linear sensitivities that may hold clues to the potential for abrupt future changes in climate.
————————
From this cspg.org/documents/Technical/Webcasts/webcast%20slides/2012/Miller%20pdf.pdf you can indeed see that Miller directly implies recent temperatures as high as the Eemian:
Greenland ice cores provide context for when Earth might have been last even warmer than the early Holocene
Accompanied by a graph with a line drawn straight across from the Holocene to the Eemian. Which seems to be the whole point of the paper, and the ambiguous language used in the title and abstract.
Please tell me Richard, what do think “unprecedented”, “higher than… in 44,000 years”, and “even warmer than the early Holocene” are supposed to mean?
phodges said :
Thank you. You are making progress.
Peter said :
Peter, I’m not sure why you are apologizing.
The Andrews et al 1972 paper clearly states :
which is what you had been saying all along.
The question is : Why did you not quote this sentence from Andrews et al 1972 right from the start ?
Why first mention McIntyre as an authority, then hand wave at Curry’s blog and Thomas et al 2009, questioning it’s conclusions and accusing me of having objections to that paper, even though I did not even say a single word about that paper, then hand wave at the 30’s as being warmer , before finally even mentioning Andrews et al 1972, albeit that you still refrain from quoting the only sentence in that paper that sustained your argument. Pekka finally did that for you.
And then you are so secretive about your own name, while misspelling others’.
Why the evasive tactics and the Gish Gallops Peter ? Why so unscientific ?
Why not just state :
My name is Peter Hodges, and I object to the Miller et al 2013 paper, since the main control on glacierization in eastern Baffin Island is snowfall, not temperature, just as Miller stated in his 1972 paper here (give the ref).
That would be such a relief, and would save everyone’s time.
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